244 files changed, 8815 insertions, 8083 deletions

diff --git a/Cargo.lock b/Cargo.lock
index e47b87964..238c21f52 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -37,9 +37,9 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.40"
+version = "1.0.41"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "28b2cd92db5cbd74e8e5028f7e27dd7aa3090e89e4f2a197cc7c8dfb69c7063b"
+checksum = "15af2628f6890fe2609a3b91bef4c83450512802e59489f9c1cb1fa5df064a61"
 
 [[package]]
 name = "anymap"
@@ -49,9 +49,9 @@ checksum = "33954243bd79057c2de7338850b85983a44588021f8a5fee574a8888c6de4344"
 
 [[package]]
 name = "arrayvec"
-version = "0.7.0"
+version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5a2f58b0bb10c380af2b26e57212856b8c9a59e0925b4c20f4a174a49734eaf7"
+checksum = "be4dc07131ffa69b8072d35f5007352af944213cde02545e2103680baed38fcd"
 
 [[package]]
 name = "atty"
@@ -216,20 +216,6 @@ dependencies = [
  "petgraph",
  "rustc-hash",
  "tracing",
- "tracing-subscriber",
- "tracing-tree",
-]
-
-[[package]]
-name = "chrono"
-version = "0.4.19"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "670ad68c9088c2a963aaa298cb369688cf3f9465ce5e2d4ca10e6e0098a1ce73"
-dependencies = [
- "libc",
- "num-integer",
- "num-traits",
- "winapi",
 ]
 
 [[package]]
@@ -347,9 +333,9 @@ dependencies = [
 
 [[package]]
 name = "env_logger"
-version = "0.8.3"
+version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "17392a012ea30ef05a610aa97dfb49496e71c9f676b27879922ea5bdf60d9d3f"
+checksum = "a19187fea3ac7e84da7dacf48de0c45d63c6a76f9490dae389aead16c243fce3"
 dependencies = [
  "log",
 ]
@@ -435,9 +421,9 @@ dependencies = [
 
 [[package]]
 name = "fst"
-version = "0.4.6"
+version = "0.4.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e398fae362f4124bbe630d99519fb2d68a03e2e3a23b441028cdcdc4f4895687"
+checksum = "7ab85b9b05e3978cc9a9cf8fea7f01b494e1a09ed3037e16ba39edc7a29eb61a"
 
 [[package]]
 name = "gimli"
@@ -591,6 +577,7 @@ dependencies = [
  "ide_assists",
  "ide_completion",
  "ide_db",
+ "ide_diagnostics",
  "ide_ssr",
  "indexmap",
  "itertools",
@@ -669,6 +656,25 @@ dependencies = [
 ]
 
 [[package]]
+name = "ide_diagnostics"
+version = "0.0.0"
+dependencies = [
+ "cfg",
+ "cov-mark",
+ "either",
+ "expect-test",
+ "hir",
+ "ide_db",
+ "itertools",
+ "profile",
+ "rustc-hash",
+ "stdx",
+ "syntax",
+ "test_utils",
+ "text_edit",
+]
+
+[[package]]
 name = "ide_ssr"
 version = "0.0.0"
 dependencies = [
@@ -735,9 +741,9 @@ dependencies = [
 
 [[package]]
 name = "itertools"
-version = "0.10.0"
+version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "37d572918e350e82412fe766d24b15e6682fb2ed2bbe018280caa810397cb319"
+checksum = "69ddb889f9d0d08a67338271fa9b62996bc788c7796a5c18cf057420aaed5eaf"
 dependencies = [
  "either",
 ]
@@ -782,9 +788,9 @@ dependencies = [
 
 [[package]]
 name = "libmimalloc-sys"
-version = "0.1.21"
+version = "0.1.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2396cf99d2f58611cd69f0efeee4af3d2e2c7b61bed433515029163aa567e65c"
+checksum = "1d1b8479c593dba88c2741fc50b92e13dbabbbe0bd504d979f244ccc1a5b1c01"
 dependencies = [
  "cc",
 ]
@@ -821,9 +827,9 @@ dependencies = [
 
 [[package]]
 name = "lsp-types"
-version = "0.89.1"
+version = "0.89.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "48b8a871b0a450bcec0e26d74a59583c8173cb9fb7d7f98889e18abb84838e0f"
+checksum = "852e0dedfd52cc32325598b2631e0eba31b7b708959676a9f837042f276b09a2"
 dependencies = [
  "bitflags",
  "serde",
@@ -889,9 +895,9 @@ dependencies = [
 
 [[package]]
 name = "mimalloc"
-version = "0.1.25"
+version = "0.1.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e7c6b11afd1e5e689ac96b6d18b1fc763398fe3d7eed99e8773426bc2033dfb"
+checksum = "fb74897ce508e6c49156fd1476fc5922cbc6e75183c65e399c765a09122e5130"
 dependencies = [
  "libmimalloc-sys",
 ]
@@ -955,25 +961,6 @@ dependencies = [
 ]
 
 [[package]]
-name = "num-integer"
-version = "0.1.44"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d2cc698a63b549a70bc047073d2949cce27cd1c7b0a4a862d08a8031bc2801db"
-dependencies = [
- "autocfg",
- "num-traits",
-]
-
-[[package]]
-name = "num-traits"
-version = "0.2.14"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9a64b1ec5cda2586e284722486d802acf1f7dbdc623e2bfc57e65ca1cd099290"
-dependencies = [
- "autocfg",
-]
-
-[[package]]
 name = "num_cpus"
 version = "1.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -991,9 +978,9 @@ checksum = "1a5b3dd1c072ee7963717671d1ca129f1048fda25edea6b752bfc71ac8854170"
 
 [[package]]
 name = "once_cell"
-version = "1.7.2"
+version = "1.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "af8b08b04175473088b46763e51ee54da5f9a164bc162f615b91bc179dbf15a3"
+checksum = "692fcb63b64b1758029e0a96ee63e049ce8c5948587f2f7208df04625e5f6b56"
 
 [[package]]
 name = "oorandom"
@@ -1217,9 +1204,9 @@ dependencies = [
 
 [[package]]
 name = "pulldown-cmark-to-cmark"
-version = "6.0.0"
+version = "6.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e8f2b9878102358ec65434fdd1a9a161f8648bb2f531acc9260e4d094c96de23"
+checksum = "6a95f396125c68d833fc40cca35532c49ab7394382f7b0e46144a4761896ce80"
 dependencies = [
  "pulldown-cmark",
 ]
@@ -1742,35 +1729,18 @@ dependencies = [
 ]
 
 [[package]]
-name = "tracing-serde"
-version = "0.1.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fb65ea441fbb84f9f6748fd496cf7f63ec9af5bca94dd86456978d055e8eb28b"
-dependencies = [
- "serde",
- "tracing-core",
-]
-
-[[package]]
 name = "tracing-subscriber"
 version = "0.2.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "aa5553bf0883ba7c9cbe493b085c29926bd41b66afc31ff72cf17ff4fb60dcd5"
 dependencies = [
- "ansi_term",
- "chrono",
  "lazy_static",
  "matchers",
  "regex",
- "serde",
- "serde_json",
  "sharded-slab",
- "smallvec",
  "thread_local",
  "tracing",
  "tracing-core",
- "tracing-log",
- "tracing-serde",
 ]
 
 [[package]]
@@ -1939,18 +1909,18 @@ checksum = "06069a848f95fceae3e5e03c0ddc8cb78452b56654ee0c8e68f938cf790fb9e3"
 
 [[package]]
 name = "xflags"
-version = "0.2.1"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "59ad6ce6a0b7224130015b4ebac796478ac04e0079f5d222a690efea06a9208a"
+checksum = "a25b85ca0fcf2d003f2b0cfdce73897c54ec3d793dfe008a64de5040209363c9"
 dependencies = [
  "xflags-macros",
 ]
 
 [[package]]
 name = "xflags-macros"
-version = "0.2.1"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c8037d3ca14996158b03c0fa905d0834906ef0fc7044df72c1f5ff690e5e62c9"
+checksum = "00055208d8839f11689012fecb42bbc024e25bf3af91b3b9879739d3cda65bf0"
 dependencies = [
  "proc-macro2",
 ]
diff --git a/PRIVACY.md b/PRIVACY.md
index 27e39ca60..718fbed12 100644
--- a/PRIVACY.md
+++ b/PRIVACY.md
@@ -1,17 +1 @@
-# Privacy Notes
-
-## LSP server binary
-
-The LSP server performs no network access in itself, but runs `cargo metadata` which will update or download the crate registry and the source code of the project dependencies.
-
-## Visual Studio Code extension
-
-The Code extension connects to GitHub to download updated LSP binaries and, if the nightly channel is selected, to perform update checks.
-
-## Other editor plugins
-
-Any other editor plugins that integrate with `rust-analyzer` are not under the control of the `rust-analyzer` developers. For any privacy concerns, you should check with their respective developers.
-
-## Others
-
-If `cargo check` is enabled (the default), any build scripts or procedural macros used by the project or its dependencies will be executed. This is also the case when `cargo check` is disabled, but build script or procedural macro support is enabled in `rust-analyzer` (on by default).
+See the [Privacy](https://rust-analyzer.github.io/manual.html#security) section of the user manual.
diff --git a/README.md b/README.md
index 5fbc03964..e01542416 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,10 @@ If you want to **use** rust-analyzer's language server with your editor of
 choice, check [the manual](https://rust-analyzer.github.io/manual.html) folder.
 It also contains some tips & tricks to help you be more productive when using rust-analyzer.
 
+## Security and Privacy
+
+See the corresponding sections of [the manual](https://rust-analyzer.github.io/manual.html#security).
+
 ## Communication
 
 For usage and troubleshooting requests, please use "IDEs and Editors" category of the Rust forum:
diff --git a/crates/base_db/src/fixture.rs b/crates/base_db/src/fixture.rs
index da4afb5eb..6ce377710 100644
--- a/crates/base_db/src/fixture.rs
+++ b/crates/base_db/src/fixture.rs
@@ -9,8 +9,8 @@ use test_utils::{
 use vfs::{file_set::FileSet, VfsPath};
 
 use crate::{
-    input::CrateName, Change, CrateGraph, CrateId, Edition, Env, FileId, FilePosition, FileRange,
-    SourceDatabaseExt, SourceRoot, SourceRootId,
+    input::CrateName, Change, CrateDisplayName, CrateGraph, CrateId, Edition, Env, FileId,
+    FilePosition, FileRange, SourceDatabaseExt, SourceRoot, SourceRootId,
 };
 
 pub const WORKSPACE: SourceRootId = SourceRootId(0);
@@ -24,6 +24,14 @@ pub trait WithFixture: Default + SourceDatabaseExt + 'static {
         (db, fixture.files[0])
     }
 
+    fn with_many_files(ra_fixture: &str) -> (Self, Vec<FileId>) {
+        let fixture = ChangeFixture::parse(ra_fixture);
+        let mut db = Self::default();
+        fixture.change.apply(&mut db);
+        assert!(fixture.file_position.is_none());
+        (db, fixture.files)
+    }
+
     fn with_files(ra_fixture: &str) -> Self {
         let fixture = ChangeFixture::parse(ra_fixture);
         let mut db = Self::default();
@@ -73,7 +81,7 @@ pub struct ChangeFixture {
 
 impl ChangeFixture {
     pub fn parse(ra_fixture: &str) -> ChangeFixture {
-        let fixture = Fixture::parse(ra_fixture);
+        let (mini_core, fixture) = Fixture::parse(ra_fixture);
         let mut change = Change::new();
 
         let mut files = Vec::new();
@@ -98,7 +106,7 @@ impl ChangeFixture {
                     let (range_or_offset, text) = extract_range_or_offset(&entry.text);
                     assert!(file_position.is_none());
                     file_position = Some((file_id, range_or_offset));
-                    text.to_string()
+                    text
                 }
             } else {
                 entry.text.clone()
@@ -106,6 +114,9 @@ impl ChangeFixture {
 
             let meta = FileMeta::from(entry);
             assert!(meta.path.starts_with(&source_root_prefix));
+            if !meta.deps.is_empty() {
+                assert!(meta.krate.is_some(), "can't specify deps without naming the crate")
+            }
 
             if meta.introduce_new_source_root {
                 roots.push(SourceRoot::new_local(mem::take(&mut file_set)));
@@ -158,6 +169,31 @@ impl ChangeFixture {
             }
         }
 
+        if let Some(mini_core) = mini_core {
+            let core_file = file_id;
+            file_id.0 += 1;
+
+            let mut fs = FileSet::default();
+            fs.insert(core_file, VfsPath::new_virtual_path("/sysroot/core/lib.rs".to_string()));
+            roots.push(SourceRoot::new_library(fs));
+
+            change.change_file(core_file, Some(Arc::new(mini_core.source_code())));
+
+            let all_crates = crate_graph.crates_in_topological_order();
+
+            let core_crate = crate_graph.add_crate_root(
+                core_file,
+                Edition::Edition2021,
+                Some(CrateDisplayName::from_canonical_name("core".to_string())),
+                CfgOptions::default(),
+                Env::default(),
+                Vec::new(),
+            );
+
+            for krate in all_crates {
+                crate_graph.add_dep(krate, CrateName::new("core").unwrap(), core_crate).unwrap();
+            }
+        }
         roots.push(SourceRoot::new_local(mem::take(&mut file_set)));
         change.set_roots(roots);
         change.set_crate_graph(crate_graph);
@@ -166,6 +202,7 @@ impl ChangeFixture {
     }
 }
 
+#[derive(Debug)]
 struct FileMeta {
     path: String,
     krate: Option<String>,
diff --git a/crates/cfg/src/lib.rs b/crates/cfg/src/lib.rs
index 03b8dd767..916d39a0b 100644
--- a/crates/cfg/src/lib.rs
+++ b/crates/cfg/src/lib.rs
@@ -1,4 +1,4 @@
-//! cfg defines conditional compiling options, `cfg` attibute parser and evaluator
+//! cfg defines conditional compiling options, `cfg` attribute parser and evaluator
 
 mod cfg_expr;
 mod dnf;
@@ -52,6 +52,7 @@ impl CfgOptions {
     }
 }
 
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct CfgDiff {
     // Invariants: No duplicates, no atom that's both in `enable` and `disable`.
     enable: Vec<CfgAtom>,
@@ -59,6 +60,20 @@ pub struct CfgDiff {
 }
 
 impl CfgDiff {
+    /// Create a new CfgDiff. Will return None if the same item appears more than once in the set
+    /// of both.
+    pub fn new(enable: Vec<CfgAtom>, disable: Vec<CfgAtom>) -> Option<CfgDiff> {
+        let mut occupied = FxHashSet::default();
+        for item in enable.iter().chain(disable.iter()) {
+            if !occupied.insert(item) {
+                // was present
+                return None;
+            }
+        }
+
+        Some(CfgDiff { enable, disable })
+    }
+
     /// Returns the total number of atoms changed by this diff.
     pub fn len(&self) -> usize {
         self.enable.len() + self.disable.len()
diff --git a/crates/hir/src/has_source.rs b/crates/hir/src/has_source.rs
index dc10a4d0f..197149c5e 100644
--- a/crates/hir/src/has_source.rs
+++ b/crates/hir/src/has_source.rs
@@ -127,7 +127,7 @@ impl HasSource for Impl {
 }
 
 impl HasSource for TypeParam {
-    type Ast = Either<ast::Trait, ast::TypeParam>;
+    type Ast = Either<ast::TypeParam, ast::Trait>;
     fn source(self, db: &dyn HirDatabase) -> Option<InFile<Self::Ast>> {
         let child_source = self.id.parent.child_source(db.upcast());
         Some(child_source.map(|it| it[self.id.local_id].clone()))
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 5bc0b2338..b7eabaabb 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -2688,18 +2688,6 @@ impl ScopeDef {
 
         items
     }
-
-    pub fn is_value_def(&self) -> bool {
-        matches!(
-            self,
-            ScopeDef::ModuleDef(ModuleDef::Function(_))
-                | ScopeDef::ModuleDef(ModuleDef::Variant(_))
-                | ScopeDef::ModuleDef(ModuleDef::Const(_))
-                | ScopeDef::ModuleDef(ModuleDef::Static(_))
-                | ScopeDef::GenericParam(GenericParam::ConstParam(_))
-                | ScopeDef::Local(_)
-        )
-    }
 }
 
 impl From<ItemInNs> for ScopeDef {
diff --git a/crates/hir/src/semantics.rs b/crates/hir/src/semantics.rs
index 613266e07..43162797e 100644
--- a/crates/hir/src/semantics.rs
+++ b/crates/hir/src/semantics.rs
@@ -51,12 +51,14 @@ impl PathResolution {
             PathResolution::Def(ModuleDef::BuiltinType(builtin)) => {
                 Some(TypeNs::BuiltinType((*builtin).into()))
             }
-            PathResolution::Def(ModuleDef::Const(_))
-            | PathResolution::Def(ModuleDef::Variant(_))
-            | PathResolution::Def(ModuleDef::Function(_))
-            | PathResolution::Def(ModuleDef::Module(_))
-            | PathResolution::Def(ModuleDef::Static(_))
-            | PathResolution::Def(ModuleDef::Trait(_)) => None,
+            PathResolution::Def(
+                ModuleDef::Const(_)
+                | ModuleDef::Variant(_)
+                | ModuleDef::Function(_)
+                | ModuleDef::Module(_)
+                | ModuleDef::Static(_)
+                | ModuleDef::Trait(_),
+            ) => None,
             PathResolution::Def(ModuleDef::TypeAlias(alias)) => {
                 Some(TypeNs::TypeAliasId((*alias).into()))
             }
@@ -65,8 +67,7 @@ impl PathResolution {
             }
             PathResolution::TypeParam(param) => Some(TypeNs::GenericParam((*param).into())),
             PathResolution::SelfType(impl_def) => Some(TypeNs::SelfType((*impl_def).into())),
-            PathResolution::AssocItem(AssocItem::Const(_))
-            | PathResolution::AssocItem(AssocItem::Function(_)) => None,
+            PathResolution::AssocItem(AssocItem::Const(_) | AssocItem::Function(_)) => None,
             PathResolution::AssocItem(AssocItem::TypeAlias(alias)) => {
                 Some(TypeNs::TypeAliasId((*alias).into()))
             }
diff --git a/crates/hir_def/src/generics.rs b/crates/hir_def/src/generics.rs
index 6933f6e3c..0f04b2bae 100644
--- a/crates/hir_def/src/generics.rs
+++ b/crates/hir_def/src/generics.rs
@@ -92,7 +92,7 @@ pub enum WherePredicateTypeTarget {
 
 #[derive(Default)]
 pub(crate) struct SourceMap {
-    pub(crate) type_params: ArenaMap<LocalTypeParamId, Either<ast::Trait, ast::TypeParam>>,
+    pub(crate) type_params: ArenaMap<LocalTypeParamId, Either<ast::TypeParam, ast::Trait>>,
     lifetime_params: ArenaMap<LocalLifetimeParamId, ast::LifetimeParam>,
     const_params: ArenaMap<LocalConstParamId, ast::ConstParam>,
 }
@@ -199,7 +199,7 @@ impl GenericParams {
                     default: None,
                     provenance: TypeParamProvenance::TraitSelf,
                 });
-                sm.type_params.insert(self_param_id, Either::Left(src.value.clone()));
+                sm.type_params.insert(self_param_id, Either::Right(src.value.clone()));
                 // add super traits as bounds on Self
                 // i.e., trait Foo: Bar is equivalent to trait Foo where Self: Bar
                 let self_param = TypeRef::Path(name![Self].into());
@@ -277,7 +277,7 @@ impl GenericParams {
                 provenance: TypeParamProvenance::TypeParamList,
             };
             let param_id = self.types.alloc(param);
-            sm.type_params.insert(param_id, Either::Right(type_param.clone()));
+            sm.type_params.insert(param_id, Either::Left(type_param.clone()));
 
             let type_ref = TypeRef::Path(name.into());
             self.fill_bounds(lower_ctx, &type_param, Either::Left(type_ref));
@@ -413,7 +413,7 @@ impl GenericParams {
 }
 
 impl HasChildSource<LocalTypeParamId> for GenericDefId {
-    type Value = Either<ast::Trait, ast::TypeParam>;
+    type Value = Either<ast::TypeParam, ast::Trait>;
     fn child_source(
         &self,
         db: &dyn DefDatabase,
@@ -449,7 +449,7 @@ impl ChildBySource for GenericDefId {
         let sm = sm.as_ref();
         for (local_id, src) in sm.value.type_params.iter() {
             let id = TypeParamId { parent: *self, local_id };
-            if let Either::Right(type_param) = src {
+            if let Either::Left(type_param) = src {
                 res[keys::TYPE_PARAM].insert(sm.with_value(type_param.clone()), id)
             }
         }
diff --git a/crates/hir_def/src/item_tree/lower.rs b/crates/hir_def/src/item_tree/lower.rs
index 3f90bda74..5b1386406 100644
--- a/crates/hir_def/src/item_tree/lower.rs
+++ b/crates/hir_def/src/item_tree/lower.rs
@@ -674,7 +674,7 @@ impl<'a> Ctx<'a> {
                     default: None,
                     provenance: TypeParamProvenance::TraitSelf,
                 });
-                sm.type_params.insert(self_param_id, Either::Left(trait_def.clone()));
+                sm.type_params.insert(self_param_id, Either::Right(trait_def.clone()));
                 // add super traits as bounds on Self
                 // i.e., trait Foo: Bar is equivalent to trait Foo where Self: Bar
                 let self_param = TypeRef::Path(name![Self].into());
diff --git a/crates/hir_def/src/item_tree/pretty.rs b/crates/hir_def/src/item_tree/pretty.rs
index b1e1b70d0..e63bc8232 100644
--- a/crates/hir_def/src/item_tree/pretty.rs
+++ b/crates/hir_def/src/item_tree/pretty.rs
@@ -63,7 +63,7 @@ impl<'a> Printer<'a> {
     fn blank(&mut self) {
         let mut iter = self.buf.chars().rev().fuse();
         match (iter.next(), iter.next()) {
-            (Some('\n'), Some('\n')) | (Some('\n'), None) | (None, None) => {}
+            (Some('\n'), Some('\n') | None) | (None, None) => {}
             (Some('\n'), Some(_)) => {
                 self.buf.push('\n');
             }
@@ -77,7 +77,7 @@ impl<'a> Printer<'a> {
 
     fn whitespace(&mut self) {
         match self.buf.chars().next_back() {
-            None | Some('\n') | Some(' ') => {}
+            None | Some('\n' | ' ') => {}
             _ => self.buf.push(' '),
         }
     }
diff --git a/crates/hir_def/src/nameres/collector.rs b/crates/hir_def/src/nameres/collector.rs
index 6fab58f15..927a7b6e8 100644
--- a/crates/hir_def/src/nameres/collector.rs
+++ b/crates/hir_def/src/nameres/collector.rs
@@ -1260,7 +1260,7 @@ impl DefCollector<'_> {
         for directive in &self.unresolved_imports {
             if let ImportSource::Import { id: import, use_tree } = &directive.import.source {
                 match (directive.import.path.segments().first(), &directive.import.path.kind) {
-                    (Some(krate), PathKind::Plain) | (Some(krate), PathKind::Abs) => {
+                    (Some(krate), PathKind::Plain | PathKind::Abs) => {
                         if diagnosed_extern_crates.contains(krate) {
                             continue;
                         }
@@ -1992,8 +1992,8 @@ mod tests {
         collector.def_map
     }
 
-    fn do_resolve(code: &str) -> DefMap {
-        let (db, _file_id) = TestDB::with_single_file(code);
+    fn do_resolve(not_ra_fixture: &str) -> DefMap {
+        let (db, _file_id) = TestDB::with_single_file(not_ra_fixture);
         let krate = db.test_crate();
 
         let edition = db.crate_graph()[krate].edition;
@@ -2005,24 +2005,37 @@ mod tests {
     fn test_macro_expand_will_stop_1() {
         do_resolve(
             r#"
-        macro_rules! foo {
-            ($($ty:ty)*) => { foo!($($ty)*); }
-        }
-        foo!(KABOOM);
-        "#,
+macro_rules! foo {
+    ($($ty:ty)*) => { foo!($($ty)*); }
+}
+foo!(KABOOM);
+"#,
+        );
+        do_resolve(
+            r#"
+macro_rules! foo {
+    ($($ty:ty)*) => { foo!(() $($ty)*); }
+}
+foo!(KABOOM);
+"#,
         );
     }
 
-    #[ignore] // this test does succeed, but takes quite a while :/
+    #[ignore]
     #[test]
     fn test_macro_expand_will_stop_2() {
+        // FIXME: this test does succeed, but takes quite a while: 90 seconds in
+        // the release mode. That's why the argument is not an ra_fixture --
+        // otherwise injection highlighting gets stuck.
+        //
+        // We need to find a way to fail this faster.
         do_resolve(
             r#"
-        macro_rules! foo {
-            ($($ty:ty)*) => { foo!($($ty)* $($ty)*); }
-        }
-        foo!(KABOOM);
-        "#,
+macro_rules! foo {
+    ($($ty:ty)*) => { foo!($($ty)* $($ty)*); }
+}
+foo!(KABOOM);
+"#,
         );
     }
 }
diff --git a/crates/hir_def/src/resolver.rs b/crates/hir_def/src/resolver.rs
index d4681fa3e..49c573087 100644
--- a/crates/hir_def/src/resolver.rs
+++ b/crates/hir_def/src/resolver.rs
@@ -605,8 +605,7 @@ fn to_value_ns(per_ns: PerNs) -> Option<ValueNs> {
         ModuleDefId::ConstId(it) => ValueNs::ConstId(it),
         ModuleDefId::StaticId(it) => ValueNs::StaticId(it),
 
-        ModuleDefId::AdtId(AdtId::EnumId(_))
-        | ModuleDefId::AdtId(AdtId::UnionId(_))
+        ModuleDefId::AdtId(AdtId::EnumId(_) | AdtId::UnionId(_))
         | ModuleDefId::TraitId(_)
         | ModuleDefId::TypeAliasId(_)
         | ModuleDefId::BuiltinType(_)
@@ -641,8 +640,7 @@ pub trait HasResolver: Copy {
 impl HasResolver for ModuleId {
     fn resolver(self, db: &dyn DefDatabase) -> Resolver {
         let mut def_map = self.def_map(db);
-        let mut modules = Vec::new();
-        modules.push((def_map.clone(), self.local_id));
+        let mut modules = vec![(def_map.clone(), self.local_id)];
         while let Some(parent) = def_map.parent() {
             def_map = parent.def_map(db);
             modules.push((def_map.clone(), parent.local_id));
diff --git a/crates/hir_def/src/visibility.rs b/crates/hir_def/src/visibility.rs
index 83500f54e..aeb1e7726 100644
--- a/crates/hir_def/src/visibility.rs
+++ b/crates/hir_def/src/visibility.rs
@@ -172,9 +172,8 @@ impl Visibility {
     /// visible in unrelated modules).
     pub(crate) fn max(self, other: Visibility, def_map: &DefMap) -> Option<Visibility> {
         match (self, other) {
-            (Visibility::Module(_), Visibility::Public)
-            | (Visibility::Public, Visibility::Module(_))
-            | (Visibility::Public, Visibility::Public) => Some(Visibility::Public),
+            (Visibility::Module(_) | Visibility::Public, Visibility::Public)
+            | (Visibility::Public, Visibility::Module(_)) => Some(Visibility::Public),
             (Visibility::Module(mod_a), Visibility::Module(mod_b)) => {
                 if mod_a.krate != mod_b.krate {
                     return None;
diff --git a/crates/hir_expand/src/builtin_macro.rs b/crates/hir_expand/src/builtin_macro.rs
index f24d1d919..4c83a2efe 100644
--- a/crates/hir_expand/src/builtin_macro.rs
+++ b/crates/hir_expand/src/builtin_macro.rs
@@ -202,7 +202,7 @@ fn assert_expand(
 
     let arg_tts = args.into_iter().flat_map(|arg| {
         quote! { &(#arg), }
-    }.token_trees).collect::<Vec<_>>();
+    }.token_trees);
 
     let expanded = quote! {
         { { (##arg_tts); } }
@@ -254,7 +254,7 @@ fn format_args_expand(
     let _format_string = args.remove(0);
     let arg_tts = args.into_iter().flat_map(|arg| {
         quote! { std::fmt::ArgumentV1::new(&(#arg), std::fmt::Display::fmt), }
-    }.token_trees).collect::<Vec<_>>();
+    }.token_trees);
     let expanded = quote! {
         std::fmt::Arguments::new_v1(&[], &[##arg_tts])
     };
diff --git a/crates/hir_expand/src/hygiene.rs b/crates/hir_expand/src/hygiene.rs
index 05c6c3fb1..848522411 100644
--- a/crates/hir_expand/src/hygiene.rs
+++ b/crates/hir_expand/src/hygiene.rs
@@ -146,10 +146,11 @@ impl HygieneInfo {
                 (&self.macro_arg.1, InFile::new(loc.kind.file_id(), arg_start))
             }
             mbe::Origin::Def => match (&*self.macro_def, self.def_start) {
-                (TokenExpander::MacroDef { def_site_token_map, .. }, Some(tt))
-                | (TokenExpander::MacroRules { def_site_token_map, .. }, Some(tt)) => {
-                    (def_site_token_map, tt)
-                }
+                (
+                    TokenExpander::MacroDef { def_site_token_map, .. }
+                    | TokenExpander::MacroRules { def_site_token_map, .. },
+                    Some(tt),
+                ) => (def_site_token_map, tt),
                 _ => panic!("`Origin::Def` used with non-`macro_rules!` macro"),
             },
         };
diff --git a/crates/hir_expand/src/lib.rs b/crates/hir_expand/src/lib.rs
index 33107aa24..c31426d7c 100644
--- a/crates/hir_expand/src/lib.rs
+++ b/crates/hir_expand/src/lib.rs
@@ -368,10 +368,11 @@ impl ExpansionInfo {
         let (token_map, tt) = match origin {
             mbe::Origin::Call => (&self.macro_arg.1, self.arg.clone()),
             mbe::Origin::Def => match (&*self.macro_def, self.def.as_ref()) {
-                (db::TokenExpander::MacroRules { def_site_token_map, .. }, Some(tt))
-                | (db::TokenExpander::MacroDef { def_site_token_map, .. }, Some(tt)) => {
-                    (def_site_token_map, tt.as_ref().map(|tt| tt.syntax().clone()))
-                }
+                (
+                    db::TokenExpander::MacroRules { def_site_token_map, .. }
+                    | db::TokenExpander::MacroDef { def_site_token_map, .. },
+                    Some(tt),
+                ) => (def_site_token_map, tt.as_ref().map(|tt| tt.syntax().clone())),
                 _ => panic!("`Origin::Def` used with non-`macro_rules!` macro"),
             },
         };
diff --git a/crates/hir_ty/Cargo.toml b/crates/hir_ty/Cargo.toml
index a1894e8d8..74129eb21 100644
--- a/crates/hir_ty/Cargo.toml
+++ b/crates/hir_ty/Cargo.toml
@@ -20,7 +20,7 @@ rustc-hash = "1.1.0"
 scoped-tls = "1"
 chalk-solve = { version = "0.68", default-features = false }
 chalk-ir = "0.68"
-chalk-recursive = "0.68"
+chalk-recursive = { version = "0.68", default-features = false }
 la-arena = { version = "0.2.0", path = "../../lib/arena" }
 once_cell = { version = "1.5.0" }
 
diff --git a/crates/hir_ty/src/chalk_db.rs b/crates/hir_ty/src/chalk_db.rs
index a4c09c742..a55b99de0 100644
--- a/crates/hir_ty/src/chalk_db.rs
+++ b/crates/hir_ty/src/chalk_db.rs
@@ -2,6 +2,7 @@
 //! about the code that Chalk needs.
 use std::sync::Arc;
 
+use cov_mark::hit;
 use log::debug;
 
 use chalk_ir::{cast::Cast, fold::shift::Shift, CanonicalVarKinds};
@@ -106,7 +107,9 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
         };
 
         fn local_impls(db: &dyn HirDatabase, module: ModuleId) -> Option<Arc<TraitImpls>> {
-            db.trait_impls_in_block(module.containing_block()?)
+            let block = module.containing_block()?;
+            hit!(block_local_impls);
+            db.trait_impls_in_block(block)
         }
 
         // Note: Since we're using impls_for_trait, only impls where the trait
diff --git a/crates/hir_ty/src/consteval.rs b/crates/hir_ty/src/consteval.rs
index 6f0bf8f8c..ab1afce08 100644
--- a/crates/hir_ty/src/consteval.rs
+++ b/crates/hir_ty/src/consteval.rs
@@ -38,8 +38,7 @@ impl ConstExt for Const {
 // FIXME: support more than just evaluating literals
 pub fn eval_usize(expr: &Expr) -> Option<u64> {
     match expr {
-        Expr::Literal(Literal::Uint(v, None))
-        | Expr::Literal(Literal::Uint(v, Some(BuiltinUint::Usize))) => (*v).try_into().ok(),
+        Expr::Literal(Literal::Uint(v, None | Some(BuiltinUint::Usize))) => (*v).try_into().ok(),
         _ => None,
     }
 }
diff --git a/crates/hir_ty/src/diagnostics/expr.rs b/crates/hir_ty/src/diagnostics/expr.rs
index b809b96a0..dc8f20138 100644
--- a/crates/hir_ty/src/diagnostics/expr.rs
+++ b/crates/hir_ty/src/diagnostics/expr.rs
@@ -56,7 +56,7 @@ impl BodyValidationDiagnostic {
     pub fn collect(db: &dyn HirDatabase, owner: DefWithBodyId) -> Vec<BodyValidationDiagnostic> {
         let _p = profile::span("BodyValidationDiagnostic::collect");
         let infer = db.infer(owner);
-        let mut validator = ExprValidator::new(owner, infer.clone());
+        let mut validator = ExprValidator::new(owner, infer);
         validator.validate_body(db);
         validator.diagnostics
     }
diff --git a/crates/hir_ty/src/diagnostics/match_check/deconstruct_pat.rs b/crates/hir_ty/src/diagnostics/match_check/deconstruct_pat.rs
index 471cd4921..e3d640a79 100644
--- a/crates/hir_ty/src/diagnostics/match_check/deconstruct_pat.rs
+++ b/crates/hir_ty/src/diagnostics/match_check/deconstruct_pat.rs
@@ -84,10 +84,7 @@ impl IntRange {
     #[inline]
     fn is_integral(ty: &Ty) -> bool {
         match ty.kind(&Interner) {
-            TyKind::Scalar(Scalar::Char)
-            | TyKind::Scalar(Scalar::Int(_))
-            | TyKind::Scalar(Scalar::Uint(_))
-            | TyKind::Scalar(Scalar::Bool) => true,
+            TyKind::Scalar(Scalar::Char | Scalar::Int(_) | Scalar::Uint(_) | Scalar::Bool) => true,
             _ => false,
         }
     }
@@ -381,7 +378,7 @@ impl Constructor {
             // Wildcards cover anything
             (_, Wildcard) => true,
             // The missing ctors are not covered by anything in the matrix except wildcards.
-            (Missing, _) | (Wildcard, _) => false,
+            (Missing | Wildcard, _) => false,
 
             (Single, Single) => true,
             (Variant(self_id), Variant(other_id)) => self_id == other_id,
@@ -523,7 +520,7 @@ impl SplitWildcard {
                 }
             }
             TyKind::Scalar(Scalar::Char) => unhandled(),
-            TyKind::Scalar(Scalar::Int(..)) | TyKind::Scalar(Scalar::Uint(..)) => unhandled(),
+            TyKind::Scalar(Scalar::Int(..) | Scalar::Uint(..)) => unhandled(),
             TyKind::Never if !cx.feature_exhaustive_patterns() && !pcx.is_top_level => {
                 smallvec![NonExhaustive]
             }
diff --git a/crates/hir_ty/src/infer/coerce.rs b/crates/hir_ty/src/infer/coerce.rs
index 4b7f31521..7be914451 100644
--- a/crates/hir_ty/src/infer/coerce.rs
+++ b/crates/hir_ty/src/infer/coerce.rs
@@ -47,10 +47,7 @@ impl<'a> InferenceContext<'a> {
         // pointers to have a chance at getting a match. See
         // https://github.com/rust-lang/rust/blob/7b805396bf46dce972692a6846ce2ad8481c5f85/src/librustc_typeck/check/coercion.rs#L877-L916
         let sig = match (ty1.kind(&Interner), ty2.kind(&Interner)) {
-            (TyKind::FnDef(..), TyKind::FnDef(..))
-            | (TyKind::Closure(..), TyKind::FnDef(..))
-            | (TyKind::FnDef(..), TyKind::Closure(..))
-            | (TyKind::Closure(..), TyKind::Closure(..)) => {
+            (TyKind::FnDef(..) | TyKind::Closure(..), TyKind::FnDef(..) | TyKind::Closure(..)) => {
                 // FIXME: we're ignoring safety here. To be more correct, if we have one FnDef and one Closure,
                 // we should be coercing the closure to a fn pointer of the safety of the FnDef
                 cov_mark::hit!(coerce_fn_reification);
@@ -448,8 +445,7 @@ fn safe_to_unsafe_fn_ty(fn_ty: FnPointer) -> FnPointer {
 
 fn coerce_mutabilities(from: Mutability, to: Mutability) -> Result<(), TypeError> {
     match (from, to) {
-        (Mutability::Mut, Mutability::Mut)
-        | (Mutability::Mut, Mutability::Not)
+        (Mutability::Mut, Mutability::Mut | Mutability::Not)
         | (Mutability::Not, Mutability::Not) => Ok(()),
         (Mutability::Not, Mutability::Mut) => Err(TypeError),
     }
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index 5ea2e5934..c3a5b979f 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -367,7 +367,7 @@ impl<'a> InferenceContext<'a> {
             Expr::Path(p) => {
                 // FIXME this could be more efficient...
                 let resolver = resolver_for_expr(self.db.upcast(), self.owner, tgt_expr);
-                self.infer_path(&resolver, p, tgt_expr.into()).unwrap_or(self.err_ty())
+                self.infer_path(&resolver, p, tgt_expr.into()).unwrap_or_else(|| self.err_ty())
             }
             Expr::Continue { .. } => TyKind::Never.intern(&Interner),
             Expr::Break { expr, label } => {
@@ -511,7 +511,7 @@ impl<'a> InferenceContext<'a> {
                         _ => None,
                     }
                 })
-                .unwrap_or(self.err_ty());
+                .unwrap_or_else(|| self.err_ty());
                 let ty = self.insert_type_vars(ty);
                 self.normalize_associated_types_in(ty)
             }
@@ -593,11 +593,11 @@ impl<'a> InferenceContext<'a> {
                     UnaryOp::Neg => {
                         match inner_ty.kind(&Interner) {
                             // Fast path for builtins
-                            TyKind::Scalar(Scalar::Int(_))
-                            | TyKind::Scalar(Scalar::Uint(_))
-                            | TyKind::Scalar(Scalar::Float(_))
-                            | TyKind::InferenceVar(_, TyVariableKind::Integer)
-                            | TyKind::InferenceVar(_, TyVariableKind::Float) => inner_ty,
+                            TyKind::Scalar(Scalar::Int(_) | Scalar::Uint(_) | Scalar::Float(_))
+                            | TyKind::InferenceVar(
+                                _,
+                                TyVariableKind::Integer | TyVariableKind::Float,
+                            ) => inner_ty,
                             // Otherwise we resolve via the std::ops::Neg trait
                             _ => self
                                 .resolve_associated_type(inner_ty, self.resolve_ops_neg_output()),
@@ -606,9 +606,7 @@ impl<'a> InferenceContext<'a> {
                     UnaryOp::Not => {
                         match inner_ty.kind(&Interner) {
                             // Fast path for builtins
-                            TyKind::Scalar(Scalar::Bool)
-                            | TyKind::Scalar(Scalar::Int(_))
-                            | TyKind::Scalar(Scalar::Uint(_))
+                            TyKind::Scalar(Scalar::Bool | Scalar::Int(_) | Scalar::Uint(_))
                             | TyKind::InferenceVar(_, TyVariableKind::Integer) => inner_ty,
                             // Otherwise we resolve via the std::ops::Not trait
                             _ => self
@@ -735,7 +733,7 @@ impl<'a> InferenceContext<'a> {
             Expr::Array(array) => {
                 let elem_ty =
                     match expected.to_option(&mut self.table).as_ref().map(|t| t.kind(&Interner)) {
-                        Some(TyKind::Array(st, _)) | Some(TyKind::Slice(st)) => st.clone(),
+                        Some(TyKind::Array(st, _) | TyKind::Slice(st)) => st.clone(),
                         _ => self.table.new_type_var(),
                     };
 
@@ -820,8 +818,10 @@ impl<'a> InferenceContext<'a> {
         for stmt in statements {
             match stmt {
                 Statement::Let { pat, type_ref, initializer } => {
-                    let decl_ty =
-                        type_ref.as_ref().map(|tr| self.make_ty(tr)).unwrap_or(self.err_ty());
+                    let decl_ty = type_ref
+                        .as_ref()
+                        .map(|tr| self.make_ty(tr))
+                        .unwrap_or_else(|| self.err_ty());
 
                     // Always use the declared type when specified
                     let mut ty = decl_ty.clone();
diff --git a/crates/hir_ty/src/infer/pat.rs b/crates/hir_ty/src/infer/pat.rs
index 035f4ded6..c79ed91ea 100644
--- a/crates/hir_ty/src/infer/pat.rs
+++ b/crates/hir_ty/src/infer/pat.rs
@@ -192,7 +192,7 @@ impl<'a> InferenceContext<'a> {
             Pat::Path(path) => {
                 // FIXME use correct resolver for the surrounding expression
                 let resolver = self.resolver.clone();
-                self.infer_path(&resolver, path, pat.into()).unwrap_or(self.err_ty())
+                self.infer_path(&resolver, path, pat.into()).unwrap_or_else(|| self.err_ty())
             }
             Pat::Bind { mode, name: _, subpat } => {
                 let mode = if mode == &BindingAnnotation::Unannotated {
@@ -297,10 +297,11 @@ fn is_non_ref_pat(body: &hir_def::body::Body, pat: PatId) -> bool {
             Expr::Literal(Literal::String(..)) => false,
             _ => true,
         },
-        Pat::Bind { mode: BindingAnnotation::Mutable, subpat: Some(subpat), .. }
-        | Pat::Bind { mode: BindingAnnotation::Unannotated, subpat: Some(subpat), .. } => {
-            is_non_ref_pat(body, *subpat)
-        }
+        Pat::Bind {
+            mode: BindingAnnotation::Mutable | BindingAnnotation::Unannotated,
+            subpat: Some(subpat),
+            ..
+        } => is_non_ref_pat(body, *subpat),
         Pat::Wild | Pat::Bind { .. } | Pat::Ref { .. } | Pat::Box { .. } | Pat::Missing => false,
     }
 }
diff --git a/crates/hir_ty/src/lower.rs b/crates/hir_ty/src/lower.rs
index 817a65c20..ea03b6a6c 100644
--- a/crates/hir_ty/src/lower.rs
+++ b/crates/hir_ty/src/lower.rs
@@ -562,7 +562,7 @@ impl<'a> TyLoweringContext<'a> {
                 },
             );
 
-            ty.unwrap_or(TyKind::Error.intern(&Interner))
+            ty.unwrap_or_else(|| TyKind::Error.intern(&Interner))
         } else {
             TyKind::Error.intern(&Interner)
         }
diff --git a/crates/hir_ty/src/op.rs b/crates/hir_ty/src/op.rs
index 0222de2bc..5ef6342d5 100644
--- a/crates/hir_ty/src/op.rs
+++ b/crates/hir_ty/src/op.rs
@@ -8,17 +8,15 @@ pub(super) fn binary_op_return_ty(op: BinaryOp, lhs_ty: Ty, rhs_ty: Ty) -> Ty {
     match op {
         BinaryOp::LogicOp(_) | BinaryOp::CmpOp(_) => TyKind::Scalar(Scalar::Bool).intern(&Interner),
         BinaryOp::Assignment { .. } => TyBuilder::unit(),
-        BinaryOp::ArithOp(ArithOp::Shl) | BinaryOp::ArithOp(ArithOp::Shr) => {
+        BinaryOp::ArithOp(ArithOp::Shl | ArithOp::Shr) => {
             // all integer combinations are valid here
             if matches!(
                 lhs_ty.kind(&Interner),
-                TyKind::Scalar(Scalar::Int(_))
-                    | TyKind::Scalar(Scalar::Uint(_))
+                TyKind::Scalar(Scalar::Int(_) | Scalar::Uint(_))
                     | TyKind::InferenceVar(_, TyVariableKind::Integer)
             ) && matches!(
                 rhs_ty.kind(&Interner),
-                TyKind::Scalar(Scalar::Int(_))
-                    | TyKind::Scalar(Scalar::Uint(_))
+                TyKind::Scalar(Scalar::Int(_) | Scalar::Uint(_))
                     | TyKind::InferenceVar(_, TyVariableKind::Integer)
             ) {
                 lhs_ty
@@ -32,15 +30,15 @@ pub(super) fn binary_op_return_ty(op: BinaryOp, lhs_ty: Ty, rhs_ty: Ty) -> Ty {
             | (TyKind::Scalar(Scalar::Uint(_)), TyKind::Scalar(Scalar::Uint(_)))
             | (TyKind::Scalar(Scalar::Float(_)), TyKind::Scalar(Scalar::Float(_))) => rhs_ty,
             // ({int}, int) | ({int}, uint)
-            (TyKind::InferenceVar(_, TyVariableKind::Integer), TyKind::Scalar(Scalar::Int(_)))
-            | (TyKind::InferenceVar(_, TyVariableKind::Integer), TyKind::Scalar(Scalar::Uint(_))) => {
-                rhs_ty
-            }
+            (
+                TyKind::InferenceVar(_, TyVariableKind::Integer),
+                TyKind::Scalar(Scalar::Int(_) | Scalar::Uint(_)),
+            ) => rhs_ty,
             // (int, {int}) | (uint, {int})
-            (TyKind::Scalar(Scalar::Int(_)), TyKind::InferenceVar(_, TyVariableKind::Integer))
-            | (TyKind::Scalar(Scalar::Uint(_)), TyKind::InferenceVar(_, TyVariableKind::Integer)) => {
-                lhs_ty
-            }
+            (
+                TyKind::Scalar(Scalar::Int(_) | Scalar::Uint(_)),
+                TyKind::InferenceVar(_, TyVariableKind::Integer),
+            ) => lhs_ty,
             // ({float} | float)
             (TyKind::InferenceVar(_, TyVariableKind::Float), TyKind::Scalar(Scalar::Float(_))) => {
                 rhs_ty
@@ -69,21 +67,15 @@ pub(super) fn binary_op_rhs_expectation(op: BinaryOp, lhs_ty: Ty) -> Ty {
         BinaryOp::Assignment { op: None } => lhs_ty,
         BinaryOp::CmpOp(CmpOp::Eq { .. }) => match lhs_ty.kind(&Interner) {
             TyKind::Scalar(_) | TyKind::Str => lhs_ty,
-            TyKind::InferenceVar(_, TyVariableKind::Integer)
-            | TyKind::InferenceVar(_, TyVariableKind::Float) => lhs_ty,
+            TyKind::InferenceVar(_, TyVariableKind::Integer | TyVariableKind::Float) => lhs_ty,
             _ => TyKind::Error.intern(&Interner),
         },
-        BinaryOp::ArithOp(ArithOp::Shl) | BinaryOp::ArithOp(ArithOp::Shr) => {
-            TyKind::Error.intern(&Interner)
-        }
+        BinaryOp::ArithOp(ArithOp::Shl | ArithOp::Shr) => TyKind::Error.intern(&Interner),
         BinaryOp::CmpOp(CmpOp::Ord { .. })
         | BinaryOp::Assignment { op: Some(_) }
         | BinaryOp::ArithOp(_) => match lhs_ty.kind(&Interner) {
-            TyKind::Scalar(Scalar::Int(_))
-            | TyKind::Scalar(Scalar::Uint(_))
-            | TyKind::Scalar(Scalar::Float(_)) => lhs_ty,
-            TyKind::InferenceVar(_, TyVariableKind::Integer)
-            | TyKind::InferenceVar(_, TyVariableKind::Float) => lhs_ty,
+            TyKind::Scalar(Scalar::Int(_) | Scalar::Uint(_) | Scalar::Float(_)) => lhs_ty,
+            TyKind::InferenceVar(_, TyVariableKind::Integer | TyVariableKind::Float) => lhs_ty,
             _ => TyKind::Error.intern(&Interner),
         },
     }
diff --git a/crates/hir_ty/src/test_db.rs b/crates/hir_ty/src/test_db.rs
index 4640ea821..b99a03492 100644
--- a/crates/hir_ty/src/test_db.rs
+++ b/crates/hir_ty/src/test_db.rs
@@ -86,16 +86,20 @@ impl FileLoader for TestDB {
 }
 
 impl TestDB {
-    pub(crate) fn module_for_file(&self, file_id: FileId) -> ModuleId {
+    pub(crate) fn module_for_file_opt(&self, file_id: FileId) -> Option<ModuleId> {
         for &krate in self.relevant_crates(file_id).iter() {
             let crate_def_map = self.crate_def_map(krate);
             for (local_id, data) in crate_def_map.modules() {
                 if data.origin.file_id() == Some(file_id) {
-                    return crate_def_map.module_id(local_id);
+                    return Some(crate_def_map.module_id(local_id));
                 }
             }
         }
-        panic!("Can't find module for file")
+        None
+    }
+
+    pub(crate) fn module_for_file(&self, file_id: FileId) -> ModuleId {
+        self.module_for_file_opt(file_id).unwrap()
     }
 
     pub(crate) fn extract_annotations(&self) -> FxHashMap<FileId, Vec<(TextRange, String)>> {
diff --git a/crates/hir_ty/src/tests.rs b/crates/hir_ty/src/tests.rs
index b873585c4..0651f34ae 100644
--- a/crates/hir_ty/src/tests.rs
+++ b/crates/hir_ty/src/tests.rs
@@ -11,23 +11,21 @@ mod incremental;
 
 use std::{collections::HashMap, env, sync::Arc};
 
-use base_db::{fixture::WithFixture, FileRange, SourceDatabase, SourceDatabaseExt};
+use base_db::{fixture::WithFixture, FileRange, SourceDatabaseExt};
 use expect_test::Expect;
 use hir_def::{
     body::{Body, BodySourceMap, SyntheticSyntax},
-    child_by_source::ChildBySource,
     db::DefDatabase,
+    expr::{ExprId, PatId},
     item_scope::ItemScope,
-    keys,
     nameres::DefMap,
     src::HasSource,
-    AssocItemId, DefWithBodyId, LocalModuleId, Lookup, ModuleDefId,
+    AssocItemId, DefWithBodyId, HasModule, LocalModuleId, Lookup, ModuleDefId,
 };
 use hir_expand::{db::AstDatabase, InFile};
 use once_cell::race::OnceBool;
 use stdx::format_to;
 use syntax::{
-    algo,
     ast::{self, AstNode, NameOwner},
     SyntaxNode,
 };
@@ -59,51 +57,55 @@ fn setup_tracing() -> Option<tracing::subscriber::DefaultGuard> {
 }
 
 fn check_types(ra_fixture: &str) {
-    check_types_impl(ra_fixture, false)
+    check_impl(ra_fixture, false, true, false)
 }
 
 fn check_types_source_code(ra_fixture: &str) {
-    check_types_impl(ra_fixture, true)
-}
-
-fn check_types_impl(ra_fixture: &str, display_source: bool) {
-    let _tracing = setup_tracing();
-    let db = TestDB::with_files(ra_fixture);
-    let mut checked_one = false;
-    for (file_id, annotations) in db.extract_annotations() {
-        for (range, expected) in annotations {
-            let ty = type_at_range(&db, FileRange { file_id, range });
-            let actual = if display_source {
-                let module = db.module_for_file(file_id);
-                ty.display_source_code(&db, module).unwrap()
-            } else {
-                ty.display_test(&db).to_string()
-            };
-            assert_eq!(expected, actual);
-            checked_one = true;
-        }
-    }
-
-    assert!(checked_one, "no `//^` annotations found");
+    check_impl(ra_fixture, false, true, true)
 }
 
 fn check_no_mismatches(ra_fixture: &str) {
-    check_mismatches_impl(ra_fixture, true)
+    check_impl(ra_fixture, true, false, false)
 }
 
-#[allow(unused)]
-fn check_mismatches(ra_fixture: &str) {
-    check_mismatches_impl(ra_fixture, false)
+fn check(ra_fixture: &str) {
+    check_impl(ra_fixture, false, false, false)
 }
 
-fn check_mismatches_impl(ra_fixture: &str, allow_none: bool) {
+fn check_impl(ra_fixture: &str, allow_none: bool, only_types: bool, display_source: bool) {
     let _tracing = setup_tracing();
-    let (db, file_id) = TestDB::with_single_file(ra_fixture);
-    let module = db.module_for_file(file_id);
-    let def_map = module.def_map(&db);
+    let (db, files) = TestDB::with_many_files(ra_fixture);
+
+    let mut had_annotations = false;
+    let mut mismatches = HashMap::new();
+    let mut types = HashMap::new();
+    for (file_id, annotations) in db.extract_annotations() {
+        for (range, expected) in annotations {
+            let file_range = FileRange { file_id, range };
+            if only_types {
+                types.insert(file_range, expected);
+            } else if expected.starts_with("type: ") {
+                types.insert(file_range, expected.trim_start_matches("type: ").to_string());
+            } else if expected.starts_with("expected") {
+                mismatches.insert(file_range, expected);
+            } else {
+                panic!("unexpected annotation: {}", expected);
+            }
+            had_annotations = true;
+        }
+    }
+    assert!(had_annotations || allow_none, "no `//^` annotations found");
 
     let mut defs: Vec<DefWithBodyId> = Vec::new();
-    visit_module(&db, &def_map, module.local_id, &mut |it| defs.push(it));
+    for file_id in files {
+        let module = db.module_for_file_opt(file_id);
+        let module = match module {
+            Some(m) => m,
+            None => continue,
+        };
+        let def_map = module.def_map(&db);
+        visit_module(&db, &def_map, module.local_id, &mut |it| defs.push(it));
+    }
     defs.sort_by_key(|def| match def {
         DefWithBodyId::FunctionId(it) => {
             let loc = it.lookup(&db);
@@ -118,37 +120,59 @@ fn check_mismatches_impl(ra_fixture: &str, allow_none: bool) {
             loc.source(&db).value.syntax().text_range().start()
         }
     });
-    let mut mismatches = HashMap::new();
-    let mut push_mismatch = |src_ptr: InFile<SyntaxNode>, mismatch: TypeMismatch| {
-        let range = src_ptr.value.text_range();
-        if src_ptr.file_id.call_node(&db).is_some() {
-            panic!("type mismatch in macro expansion");
-        }
-        let file_range = FileRange { file_id: src_ptr.file_id.original_file(&db), range };
-        let actual = format!(
-            "expected {}, got {}",
-            mismatch.expected.display_test(&db),
-            mismatch.actual.display_test(&db)
-        );
-        mismatches.insert(file_range, actual);
-    };
+    let mut unexpected_type_mismatches = String::new();
     for def in defs {
         let (_body, body_source_map) = db.body_with_source_map(def);
         let inference_result = db.infer(def);
+
+        for (pat, ty) in inference_result.type_of_pat.iter() {
+            let node = match pat_node(&body_source_map, pat, &db) {
+                Some(value) => value,
+                None => continue,
+            };
+            let range = node.as_ref().original_file_range(&db);
+            if let Some(expected) = types.remove(&range) {
+                let actual = if display_source {
+                    ty.display_source_code(&db, def.module(&db)).unwrap()
+                } else {
+                    ty.display_test(&db).to_string()
+                };
+                assert_eq!(actual, expected);
+            }
+        }
+
+        for (expr, ty) in inference_result.type_of_expr.iter() {
+            let node = match expr_node(&body_source_map, expr, &db) {
+                Some(value) => value,
+                None => continue,
+            };
+            let range = node.as_ref().original_file_range(&db);
+            if let Some(expected) = types.remove(&range) {
+                let actual = if display_source {
+                    ty.display_source_code(&db, def.module(&db)).unwrap()
+                } else {
+                    ty.display_test(&db).to_string()
+                };
+                assert_eq!(actual, expected);
+            }
+        }
+
         for (pat, mismatch) in inference_result.pat_type_mismatches() {
-            let syntax_ptr = match body_source_map.pat_syntax(pat) {
-                Ok(sp) => {
-                    let root = db.parse_or_expand(sp.file_id).unwrap();
-                    sp.map(|ptr| {
-                        ptr.either(
-                            |it| it.to_node(&root).syntax().clone(),
-                            |it| it.to_node(&root).syntax().clone(),
-                        )
-                    })
-                }
-                Err(SyntheticSyntax) => continue,
+            let node = match pat_node(&body_source_map, pat, &db) {
+                Some(value) => value,
+                None => continue,
             };
-            push_mismatch(syntax_ptr, mismatch.clone());
+            let range = node.as_ref().original_file_range(&db);
+            let actual = format!(
+                "expected {}, got {}",
+                mismatch.expected.display_test(&db),
+                mismatch.actual.display_test(&db)
+            );
+            if let Some(annotation) = mismatches.remove(&range) {
+                assert_eq!(actual, annotation);
+            } else {
+                format_to!(unexpected_type_mismatches, "{:?}: {}\n", range.range, actual);
+            }
         }
         for (expr, mismatch) in inference_result.expr_type_mismatches() {
             let node = match body_source_map.expr_syntax(expr) {
@@ -158,45 +182,70 @@ fn check_mismatches_impl(ra_fixture: &str, allow_none: bool) {
                 }
                 Err(SyntheticSyntax) => continue,
             };
-            push_mismatch(node, mismatch.clone());
-        }
-    }
-    let mut checked_one = false;
-    for (file_id, annotations) in db.extract_annotations() {
-        for (range, expected) in annotations {
-            let file_range = FileRange { file_id, range };
-            if let Some(mismatch) = mismatches.remove(&file_range) {
-                assert_eq!(mismatch, expected);
+            let range = node.as_ref().original_file_range(&db);
+            let actual = format!(
+                "expected {}, got {}",
+                mismatch.expected.display_test(&db),
+                mismatch.actual.display_test(&db)
+            );
+            if let Some(annotation) = mismatches.remove(&range) {
+                assert_eq!(actual, annotation);
             } else {
-                assert!(false, "Expected mismatch not encountered: {}\n", expected);
+                format_to!(unexpected_type_mismatches, "{:?}: {}\n", range.range, actual);
             }
-            checked_one = true;
         }
     }
+
     let mut buf = String::new();
-    for (range, mismatch) in mismatches {
-        format_to!(buf, "{:?}: {}\n", range.range, mismatch,);
+    if !unexpected_type_mismatches.is_empty() {
+        format_to!(buf, "Unexpected type mismatches:\n{}", unexpected_type_mismatches);
+    }
+    if !mismatches.is_empty() {
+        format_to!(buf, "Unchecked mismatch annotations:\n");
+        for m in mismatches {
+            format_to!(buf, "{:?}: {}\n", m.0.range, m.1);
+        }
     }
-    assert!(buf.is_empty(), "Unexpected type mismatches:\n{}", buf);
+    if !types.is_empty() {
+        format_to!(buf, "Unchecked type annotations:\n");
+        for t in types {
+            format_to!(buf, "{:?}: type {}\n", t.0.range, t.1);
+        }
+    }
+    assert!(buf.is_empty(), "{}", buf);
+}
 
-    assert!(checked_one || allow_none, "no `//^` annotations found");
+fn expr_node(
+    body_source_map: &BodySourceMap,
+    expr: ExprId,
+    db: &TestDB,
+) -> Option<InFile<SyntaxNode>> {
+    Some(match body_source_map.expr_syntax(expr) {
+        Ok(sp) => {
+            let root = db.parse_or_expand(sp.file_id).unwrap();
+            sp.map(|ptr| ptr.to_node(&root).syntax().clone())
+        }
+        Err(SyntheticSyntax) => return None,
+    })
 }
 
-fn type_at_range(db: &TestDB, pos: FileRange) -> Ty {
-    let file = db.parse(pos.file_id).ok().unwrap();
-    let expr = algo::find_node_at_range::<ast::Expr>(file.syntax(), pos.range).unwrap();
-    let fn_def = expr.syntax().ancestors().find_map(ast::Fn::cast).unwrap();
-    let module = db.module_for_file(pos.file_id);
-    let func = *module.child_by_source(db)[keys::FUNCTION]
-        .get(&InFile::new(pos.file_id.into(), fn_def))
-        .unwrap();
-
-    let (_body, source_map) = db.body_with_source_map(func.into());
-    if let Some(expr_id) = source_map.node_expr(InFile::new(pos.file_id.into(), &expr)) {
-        let infer = db.infer(func.into());
-        return infer[expr_id].clone();
-    }
-    panic!("Can't find expression")
+fn pat_node(
+    body_source_map: &BodySourceMap,
+    pat: PatId,
+    db: &TestDB,
+) -> Option<InFile<SyntaxNode>> {
+    Some(match body_source_map.pat_syntax(pat) {
+        Ok(sp) => {
+            let root = db.parse_or_expand(sp.file_id).unwrap();
+            sp.map(|ptr| {
+                ptr.either(
+                    |it| it.to_node(&root).syntax().clone(),
+                    |it| it.to_node(&root).syntax().clone(),
+                )
+            })
+        }
+        Err(SyntheticSyntax) => return None,
+    })
 }
 
 fn infer(ra_fixture: &str) -> String {
diff --git a/crates/hir_ty/src/tests/coercion.rs b/crates/hir_ty/src/tests/coercion.rs
index 71047703d..87089f09d 100644
--- a/crates/hir_ty/src/tests/coercion.rs
+++ b/crates/hir_ty/src/tests/coercion.rs
@@ -1,380 +1,157 @@
-use expect_test::expect;
-
-use super::{check_infer, check_infer_with_mismatches, check_no_mismatches, check_types};
+use super::{check, check_no_mismatches, check_types};
 
 #[test]
-fn infer_block_expr_type_mismatch() {
-    check_infer(
+fn block_expr_type_mismatch() {
+    // FIXME fix double type mismatch
+    check(
         r"
-        fn test() {
-            let a: i32 = { 1i64 };
-        }
+fn test() {
+    let a: i32 = { 1i64 };
+              // ^^^^^^^^ expected i32, got i64
+                // ^^^^ expected i32, got i64
+}
         ",
-        expect![[r"
-            10..40 '{     ...4 }; }': ()
-            20..21 'a': i32
-            29..37 '{ 1i64 }': i64
-            31..35 '1i64': i64
-        "]],
     );
 }
 
 #[test]
 fn coerce_places() {
-    check_infer(
+    check_no_mismatches(
         r#"
-        struct S<T> { a: T }
+//- minicore: coerce_unsized
+struct S<T> { a: T }
 
-        fn f<T>(_: &[T]) -> T { loop {} }
-        fn g<T>(_: S<&[T]>) -> T { loop {} }
+fn f<T>(_: &[T]) -> T { loop {} }
+fn g<T>(_: S<&[T]>) -> T { loop {} }
 
-        fn gen<T>() -> *mut [T; 2] { loop {} }
-        fn test1<U>() -> *mut [U] {
-            gen()
-        }
-
-        fn test2() {
-            let arr: &[u8; 1] = &[1];
-
-            let a: &[_] = arr;
-            let b = f(arr);
-            let c: &[_] = { arr };
-            let d = g(S { a: arr });
-            let e: [&[_]; 1] = [arr];
-            let f: [&[_]; 2] = [arr; 2];
-            let g: (&[_], &[_]) = (arr, arr);
-        }
+fn gen<T>() -> *mut [T; 2] { loop {} }
+fn test1<U>() -> *mut [U] {
+    gen()
+}
 
-        #[lang = "sized"]
-        pub trait Sized {}
-        #[lang = "unsize"]
-        pub trait Unsize<T: ?Sized> {}
-        #[lang = "coerce_unsized"]
-        pub trait CoerceUnsized<T> {}
+fn test2() {
+    let arr: &[u8; 1] = &[1];
 
-        impl<'a, 'b: 'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<&'a U> for &'b T {}
-        impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*mut U> for *mut T {}
-        "#,
-        expect![[r#"
-            30..31 '_': &[T]
-            44..55 '{ loop {} }': T
-            46..53 'loop {}': !
-            51..53 '{}': ()
-            64..65 '_': S<&[T]>
-            81..92 '{ loop {} }': T
-            83..90 'loop {}': !
-            88..90 '{}': ()
-            121..132 '{ loop {} }': *mut [T; 2]
-            123..130 'loop {}': !
-            128..130 '{}': ()
-            159..172 '{     gen() }': *mut [U]
-            165..168 'gen': fn gen<U>() -> *mut [U; 2]
-            165..170 'gen()': *mut [U; 2]
-            185..419 '{     ...rr); }': ()
-            195..198 'arr': &[u8; 1]
-            211..215 '&[1]': &[u8; 1]
-            212..215 '[1]': [u8; 1]
-            213..214 '1': u8
-            226..227 'a': &[u8]
-            236..239 'arr': &[u8; 1]
-            249..250 'b': u8
-            253..254 'f': fn f<u8>(&[u8]) -> u8
-            253..259 'f(arr)': u8
-            255..258 'arr': &[u8; 1]
-            269..270 'c': &[u8]
-            279..286 '{ arr }': &[u8]
-            281..284 'arr': &[u8; 1]
-            296..297 'd': u8
-            300..301 'g': fn g<u8>(S<&[u8]>) -> u8
-            300..315 'g(S { a: arr })': u8
-            302..314 'S { a: arr }': S<&[u8]>
-            309..312 'arr': &[u8; 1]
-            325..326 'e': [&[u8]; 1]
-            340..345 '[arr]': [&[u8]; 1]
-            341..344 'arr': &[u8; 1]
-            355..356 'f': [&[u8]; 2]
-            370..378 '[arr; 2]': [&[u8]; 2]
-            371..374 'arr': &[u8; 1]
-            376..377 '2': usize
-            388..389 'g': (&[u8], &[u8])
-            406..416 '(arr, arr)': (&[u8], &[u8])
-            407..410 'arr': &[u8; 1]
-            412..415 'arr': &[u8; 1]
-        "#]],
+    let a: &[_] = arr;
+    let b = f(arr);
+    let c: &[_] = { arr };
+    let d = g(S { a: arr });
+    let e: [&[_]; 1] = [arr];
+    let f: [&[_]; 2] = [arr; 2];
+    let g: (&[_], &[_]) = (arr, arr);
+}
+"#,
     );
 }
 
 #[test]
-fn infer_let_stmt_coerce() {
-    check_infer(
+fn let_stmt_coerce() {
+    check_no_mismatches(
         r"
-        fn test() {
-            let x: &[isize] = &[1];
-            let x: *const [isize] = &[1];
-        }
-        ",
-        expect![[r#"
-            10..75 '{     ...[1]; }': ()
-            20..21 'x': &[isize]
-            34..38 '&[1]': &[isize; 1]
-            35..38 '[1]': [isize; 1]
-            36..37 '1': isize
-            48..49 'x': *const [isize]
-            68..72 '&[1]': &[isize; 1]
-            69..72 '[1]': [isize; 1]
-            70..71 '1': isize
-        "#]],
+//- minicore: coerce_unsized
+fn test() {
+    let x: &[isize] = &[1];
+    let x: *const [isize] = &[1];
+}
+",
     );
 }
 
 #[test]
-fn infer_custom_coerce_unsized() {
-    check_infer(
+fn custom_coerce_unsized() {
+    check(
         r#"
-        struct A<T: ?Sized>(*const T);
-        struct B<T: ?Sized>(*const T);
-        struct C<T: ?Sized> { inner: *const T }
+//- minicore: coerce_unsized
+use core::{marker::Unsize, ops::CoerceUnsized};
 
-        impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<B<U>> for B<T> {}
-        impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<C<U>> for C<T> {}
+struct A<T: ?Sized>(*const T);
+struct B<T: ?Sized>(*const T);
+struct C<T: ?Sized> { inner: *const T }
 
-        fn foo1<T>(x: A<[T]>) -> A<[T]> { x }
-        fn foo2<T>(x: B<[T]>) -> B<[T]> { x }
-        fn foo3<T>(x: C<[T]>) -> C<[T]> { x }
+impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<B<U>> for B<T> {}
+impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<C<U>> for C<T> {}
 
-        fn test(a: A<[u8; 2]>, b: B<[u8; 2]>, c: C<[u8; 2]>) {
-            let d = foo1(a);
-            let e = foo2(b);
-            let f = foo3(c);
-        }
+fn foo1<T>(x: A<[T]>) -> A<[T]> { x }
+fn foo2<T>(x: B<[T]>) -> B<[T]> { x }
+fn foo3<T>(x: C<[T]>) -> C<[T]> { x }
 
-
-        #[lang = "sized"]
-        pub trait Sized {}
-        #[lang = "unsize"]
-        pub trait Unsize<T: ?Sized> {}
-        #[lang = "coerce_unsized"]
-        pub trait CoerceUnsized<T> {}
-
-        impl<'a, 'b: 'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<&'a U> for &'b T {}
-        impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*mut U> for *mut T {}
-        "#,
-        expect![[r#"
-            257..258 'x': A<[T]>
-            278..283 '{ x }': A<[T]>
-            280..281 'x': A<[T]>
-            295..296 'x': B<[T]>
-            316..321 '{ x }': B<[T]>
-            318..319 'x': B<[T]>
-            333..334 'x': C<[T]>
-            354..359 '{ x }': C<[T]>
-            356..357 'x': C<[T]>
-            369..370 'a': A<[u8; 2]>
-            384..385 'b': B<[u8; 2]>
-            399..400 'c': C<[u8; 2]>
-            414..480 '{     ...(c); }': ()
-            424..425 'd': A<[{unknown}]>
-            428..432 'foo1': fn foo1<{unknown}>(A<[{unknown}]>) -> A<[{unknown}]>
-            428..435 'foo1(a)': A<[{unknown}]>
-            433..434 'a': A<[u8; 2]>
-            445..446 'e': B<[u8]>
-            449..453 'foo2': fn foo2<u8>(B<[u8]>) -> B<[u8]>
-            449..456 'foo2(b)': B<[u8]>
-            454..455 'b': B<[u8; 2]>
-            466..467 'f': C<[u8]>
-            470..474 'foo3': fn foo3<u8>(C<[u8]>) -> C<[u8]>
-            470..477 'foo3(c)': C<[u8]>
-            475..476 'c': C<[u8; 2]>
-        "#]],
+fn test(a: A<[u8; 2]>, b: B<[u8; 2]>, c: C<[u8; 2]>) {
+    let d = foo1(a);
+              // ^ expected A<[{unknown}]>, got A<[u8; 2]>
+    let e = foo2(b);
+     // ^ type: B<[u8]>
+    let f = foo3(c);
+     // ^ type: C<[u8]>
+}
+"#,
     );
 }
 
 #[test]
-fn infer_if_coerce() {
-    check_infer(
+fn if_coerce() {
+    check_no_mismatches(
         r#"
-        fn foo<T>(x: &[T]) -> &[T] { loop {} }
-        fn test() {
-            let x = if true {
-                foo(&[1])
-            } else {
-                &[1]
-            };
-        }
-
-
-        #[lang = "sized"]
-        pub trait Sized {}
-        #[lang = "unsize"]
-        pub trait Unsize<T: ?Sized> {}
-        "#,
-        expect![[r#"
-            10..11 'x': &[T]
-            27..38 '{ loop {} }': &[T]
-            29..36 'loop {}': !
-            34..36 '{}': ()
-            49..125 '{     ...  }; }': ()
-            59..60 'x': &[i32]
-            63..122 'if tru...     }': &[i32]
-            66..70 'true': bool
-            71..96 '{     ...     }': &[i32]
-            81..84 'foo': fn foo<i32>(&[i32]) -> &[i32]
-            81..90 'foo(&[1])': &[i32]
-            85..89 '&[1]': &[i32; 1]
-            86..89 '[1]': [i32; 1]
-            87..88 '1': i32
-            102..122 '{     ...     }': &[i32; 1]
-            112..116 '&[1]': &[i32; 1]
-            113..116 '[1]': [i32; 1]
-            114..115 '1': i32
-        "#]],
+//- minicore: coerce_unsized
+fn foo<T>(x: &[T]) -> &[T] { x }
+fn test() {
+    let x = if true {
+        foo(&[1])
+    } else {
+        &[1]
+    };
+}
+"#,
     );
 }
 
 #[test]
-fn infer_if_else_coerce() {
-    check_infer(
+fn if_else_coerce() {
+    check_no_mismatches(
         r#"
-        fn foo<T>(x: &[T]) -> &[T] { loop {} }
-        fn test() {
-            let x = if true {
-                &[1]
-            } else {
-                foo(&[1])
-            };
-        }
-
-        #[lang = "sized"]
-        pub trait Sized {}
-        #[lang = "unsize"]
-        pub trait Unsize<T: ?Sized> {}
-        #[lang = "coerce_unsized"]
-        pub trait CoerceUnsized<T> {}
-
-        impl<'a, 'b: 'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<&'a U> for &'b T {}
-        impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*mut U> for *mut T {}
-        "#,
-        expect![[r#"
-            10..11 'x': &[T]
-            27..38 '{ loop {} }': &[T]
-            29..36 'loop {}': !
-            34..36 '{}': ()
-            49..125 '{     ...  }; }': ()
-            59..60 'x': &[i32]
-            63..122 'if tru...     }': &[i32]
-            66..70 'true': bool
-            71..91 '{     ...     }': &[i32; 1]
-            81..85 '&[1]': &[i32; 1]
-            82..85 '[1]': [i32; 1]
-            83..84 '1': i32
-            97..122 '{     ...     }': &[i32]
-            107..110 'foo': fn foo<i32>(&[i32]) -> &[i32]
-            107..116 'foo(&[1])': &[i32]
-            111..115 '&[1]': &[i32; 1]
-            112..115 '[1]': [i32; 1]
-            113..114 '1': i32
-        "#]],
+//- minicore: coerce_unsized
+fn foo<T>(x: &[T]) -> &[T] { x }
+fn test() {
+    let x = if true {
+        &[1]
+    } else {
+        foo(&[1])
+    };
+}
+"#,
     )
 }
 
 #[test]
-fn infer_match_first_coerce() {
-    check_infer(
+fn match_first_coerce() {
+    check_no_mismatches(
         r#"
-        fn foo<T>(x: &[T]) -> &[T] { loop {} }
-        fn test(i: i32) {
-            let x = match i {
-                2 => foo(&[2]),
-                1 => &[1],
-                _ => &[3],
-            };
-        }
-
-        #[lang = "sized"]
-        pub trait Sized {}
-        #[lang = "unsize"]
-        pub trait Unsize<T: ?Sized> {}
-        "#,
-        expect![[r#"
-            10..11 'x': &[T]
-            27..38 '{ loop {} }': &[T]
-            29..36 'loop {}': !
-            34..36 '{}': ()
-            47..48 'i': i32
-            55..149 '{     ...  }; }': ()
-            65..66 'x': &[i32]
-            69..146 'match ...     }': &[i32]
-            75..76 'i': i32
-            87..88 '2': i32
-            87..88 '2': i32
-            92..95 'foo': fn foo<i32>(&[i32]) -> &[i32]
-            92..101 'foo(&[2])': &[i32]
-            96..100 '&[2]': &[i32; 1]
-            97..100 '[2]': [i32; 1]
-            98..99 '2': i32
-            111..112 '1': i32
-            111..112 '1': i32
-            116..120 '&[1]': &[i32; 1]
-            117..120 '[1]': [i32; 1]
-            118..119 '1': i32
-            130..131 '_': i32
-            135..139 '&[3]': &[i32; 1]
-            136..139 '[3]': [i32; 1]
-            137..138 '3': i32
-        "#]],
+//- minicore: coerce_unsized
+fn foo<T>(x: &[T]) -> &[T] { x }
+fn test(i: i32) {
+    let x = match i {
+        2 => foo(&[2]),
+        1 => &[1],
+        _ => &[3],
+    };
+}
+"#,
     );
 }
 
 #[test]
-fn infer_match_second_coerce() {
-    check_infer(
+fn match_second_coerce() {
+    check_no_mismatches(
         r#"
-        fn foo<T>(x: &[T]) -> &[T] { loop {} }
-        fn test(i: i32) {
-            let x = match i {
-                1 => &[1],
-                2 => foo(&[2]),
-                _ => &[3],
-            };
-        }
-
-        #[lang = "sized"]
-        pub trait Sized {}
-        #[lang = "unsize"]
-        pub trait Unsize<T: ?Sized> {}
-        #[lang = "coerce_unsized"]
-        pub trait CoerceUnsized<T> {}
-
-        impl<'a, 'b: 'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<&'a U> for &'b T {}
-        impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*mut U> for *mut T {}
-        "#,
-        expect![[r#"
-            10..11 'x': &[T]
-            27..38 '{ loop {} }': &[T]
-            29..36 'loop {}': !
-            34..36 '{}': ()
-            47..48 'i': i32
-            55..149 '{     ...  }; }': ()
-            65..66 'x': &[i32]
-            69..146 'match ...     }': &[i32]
-            75..76 'i': i32
-            87..88 '1': i32
-            87..88 '1': i32
-            92..96 '&[1]': &[i32; 1]
-            93..96 '[1]': [i32; 1]
-            94..95 '1': i32
-            106..107 '2': i32
-            106..107 '2': i32
-            111..114 'foo': fn foo<i32>(&[i32]) -> &[i32]
-            111..120 'foo(&[2])': &[i32]
-            115..119 '&[2]': &[i32; 1]
-            116..119 '[2]': [i32; 1]
-            117..118 '2': i32
-            130..131 '_': i32
-            135..139 '&[3]': &[i32; 1]
-            136..139 '[3]': [i32; 1]
-            137..138 '3': i32
-        "#]],
+//- minicore: coerce_unsized
+fn foo<T>(x: &[T]) -> &[T] { loop {} }
+fn test(i: i32) {
+    let x = match i {
+        1 => &[1],
+        2 => foo(&[2]),
+        _ => &[3],
+    };
+}
+"#,
     );
 }
 
@@ -382,207 +159,103 @@ fn infer_match_second_coerce() {
 fn coerce_merge_one_by_one1() {
     cov_mark::check!(coerce_merge_fail_fallback);
 
-    check_infer(
+    check(
         r"
-        fn test() {
-            let t = &mut 1;
-            let x = match 1 {
-                1 => t as *mut i32,
-                2 => t as &i32,
-                _ => t as *const i32,
-            };
-        }
+fn test() {
+    let t = &mut 1;
+    let x = match 1 {
+        1 => t as *mut i32,
+        2 => t as &i32,
+           //^^^^^^^^^ expected *mut i32, got &i32
+        _ => t as *const i32,
+    };
+    x;
+  //^ type: *const i32
+}
         ",
-        expect![[r"
-            10..144 '{     ...  }; }': ()
-            20..21 't': &mut i32
-            24..30 '&mut 1': &mut i32
-            29..30 '1': i32
-            40..41 'x': *const i32
-            44..141 'match ...     }': *const i32
-            50..51 '1': i32
-            62..63 '1': i32
-            62..63 '1': i32
-            67..68 't': &mut i32
-            67..80 't as *mut i32': *mut i32
-            90..91 '2': i32
-            90..91 '2': i32
-            95..96 't': &mut i32
-            95..104 't as &i32': &i32
-            114..115 '_': i32
-            119..120 't': &mut i32
-            119..134 't as *const i32': *const i32
-    "]],
     );
 }
 
 #[test]
 fn return_coerce_unknown() {
-    check_infer_with_mismatches(
+    check_types(
         r"
-        fn foo() -> u32 {
-            return unknown;
-        }
+fn foo() -> u32 {
+    return unknown;
+         //^^^^^^^ u32
+}
         ",
-        expect![[r"
-            16..39 '{     ...own; }': u32
-            22..36 'return unknown': !
-            29..36 'unknown': u32
-        "]],
     );
 }
 
 #[test]
 fn coerce_autoderef() {
-    check_infer_with_mismatches(
+    check_no_mismatches(
         r"
-        struct Foo;
-        fn takes_ref_foo(x: &Foo) {}
-        fn test() {
-            takes_ref_foo(&Foo);
-            takes_ref_foo(&&Foo);
-            takes_ref_foo(&&&Foo);
-        }
-        ",
-        expect![[r"
-            29..30 'x': &Foo
-            38..40 '{}': ()
-            51..132 '{     ...oo); }': ()
-            57..70 'takes_ref_foo': fn takes_ref_foo(&Foo)
-            57..76 'takes_...(&Foo)': ()
-            71..75 '&Foo': &Foo
-            72..75 'Foo': Foo
-            82..95 'takes_ref_foo': fn takes_ref_foo(&Foo)
-            82..102 'takes_...&&Foo)': ()
-            96..101 '&&Foo': &&Foo
-            97..101 '&Foo': &Foo
-            98..101 'Foo': Foo
-            108..121 'takes_ref_foo': fn takes_ref_foo(&Foo)
-            108..129 'takes_...&&Foo)': ()
-            122..128 '&&&Foo': &&&Foo
-            123..128 '&&Foo': &&Foo
-            124..128 '&Foo': &Foo
-            125..128 'Foo': Foo
-        "]],
+struct Foo;
+fn takes_ref_foo(x: &Foo) {}
+fn test() {
+    takes_ref_foo(&Foo);
+    takes_ref_foo(&&Foo);
+    takes_ref_foo(&&&Foo);
+}",
     );
 }
 
 #[test]
 fn coerce_autoderef_generic() {
-    check_infer_with_mismatches(
-        r"
-        struct Foo;
-        fn takes_ref<T>(x: &T) -> T { *x }
-        fn test() {
-            takes_ref(&Foo);
-            takes_ref(&&Foo);
-            takes_ref(&&&Foo);
-        }
-        ",
-        expect![[r"
-            28..29 'x': &T
-            40..46 '{ *x }': T
-            42..44 '*x': T
-            43..44 'x': &T
-            57..126 '{     ...oo); }': ()
-            63..72 'takes_ref': fn takes_ref<Foo>(&Foo) -> Foo
-            63..78 'takes_ref(&Foo)': Foo
-            73..77 '&Foo': &Foo
-            74..77 'Foo': Foo
-            84..93 'takes_ref': fn takes_ref<&Foo>(&&Foo) -> &Foo
-            84..100 'takes_...&&Foo)': &Foo
-            94..99 '&&Foo': &&Foo
-            95..99 '&Foo': &Foo
-            96..99 'Foo': Foo
-            106..115 'takes_ref': fn takes_ref<&&Foo>(&&&Foo) -> &&Foo
-            106..123 'takes_...&&Foo)': &&Foo
-            116..122 '&&&Foo': &&&Foo
-            117..122 '&&Foo': &&Foo
-            118..122 '&Foo': &Foo
-            119..122 'Foo': Foo
-        "]],
+    check_no_mismatches(
+        r#"
+struct Foo;
+fn takes_ref<T>(x: &T) -> T { *x }
+fn test() {
+    takes_ref(&Foo);
+    takes_ref(&&Foo);
+    takes_ref(&&&Foo);
+}
+"#,
     );
 }
 
 #[test]
 fn coerce_autoderef_block() {
-    check_infer_with_mismatches(
+    check_no_mismatches(
         r#"
-        struct String {}
-        #[lang = "deref"]
-        trait Deref { type Target; }
-        impl Deref for String { type Target = str; }
-        fn takes_ref_str(x: &str) {}
-        fn returns_string() -> String { loop {} }
-        fn test() {
-            takes_ref_str(&{ returns_string() });
-        }
-        "#,
-        expect![[r"
-            126..127 'x': &str
-            135..137 '{}': ()
-            168..179 '{ loop {} }': String
-            170..177 'loop {}': !
-            175..177 '{}': ()
-            190..235 '{     ... }); }': ()
-            196..209 'takes_ref_str': fn takes_ref_str(&str)
-            196..232 'takes_...g() })': ()
-            210..231 '&{ ret...ng() }': &String
-            211..231 '{ retu...ng() }': String
-            213..227 'returns_string': fn returns_string() -> String
-            213..229 'return...ring()': String
-        "]],
+//- minicore: deref
+struct String {}
+impl core::ops::Deref for String { type Target = str; }
+fn takes_ref_str(x: &str) {}
+fn returns_string() -> String { loop {} }
+fn test() {
+    takes_ref_str(&{ returns_string() });
+}
+"#,
     );
 }
 
 #[test]
 fn closure_return_coerce() {
-    check_infer_with_mismatches(
+    check_no_mismatches(
         r"
-        fn foo() {
-            let x = || {
-                if true {
-                    return &1u32;
-                }
-                &&1u32
-            };
+fn foo() {
+    let x = || {
+        if true {
+            return &1u32;
         }
-        ",
-        expect![[r"
-            9..105 '{     ...  }; }': ()
-            19..20 'x': || -> &u32
-            23..102 '|| {  ...     }': || -> &u32
-            26..102 '{     ...     }': &u32
-            36..81 'if tru...     }': ()
-            39..43 'true': bool
-            44..81 '{     ...     }': ()
-            58..70 'return &1u32': !
-            65..70 '&1u32': &u32
-            66..70 '1u32': u32
-            90..96 '&&1u32': &&u32
-            91..96 '&1u32': &u32
-            92..96 '1u32': u32
-        "]],
+        &&1u32
+    };
+}",
     );
 }
 
 #[test]
 fn coerce_fn_item_to_fn_ptr() {
-    check_infer_with_mismatches(
+    check_no_mismatches(
         r"
-        fn foo(x: u32) -> isize { 1 }
-        fn test() {
-            let f: fn(u32) -> isize = foo;
-        }
-        ",
-        expect![[r"
-            7..8 'x': u32
-            24..29 '{ 1 }': isize
-            26..27 '1': isize
-            40..78 '{     ...foo; }': ()
-            50..51 'f': fn(u32) -> isize
-            72..75 'foo': fn foo(u32) -> isize
-        "]],
+fn foo(x: u32) -> isize { 1 }
+fn test() {
+    let f: fn(u32) -> isize = foo;
+}",
     );
 }
 
@@ -590,340 +263,160 @@ fn coerce_fn_item_to_fn_ptr() {
 fn coerce_fn_items_in_match_arms() {
     cov_mark::check!(coerce_fn_reification);
 
-    check_infer_with_mismatches(
+    check_types(
         r"
-        fn foo1(x: u32) -> isize { 1 }
-        fn foo2(x: u32) -> isize { 2 }
-        fn foo3(x: u32) -> isize { 3 }
-        fn test() {
-            let x = match 1 {
-                1 => foo1,
-                2 => foo2,
-                _ => foo3,
-            };
-        }
-        ",
-        expect![[r"
-            8..9 'x': u32
-            25..30 '{ 1 }': isize
-            27..28 '1': isize
-            39..40 'x': u32
-            56..61 '{ 2 }': isize
-            58..59 '2': isize
-            70..71 'x': u32
-            87..92 '{ 3 }': isize
-            89..90 '3': isize
-            103..192 '{     ...  }; }': ()
-            113..114 'x': fn(u32) -> isize
-            117..189 'match ...     }': fn(u32) -> isize
-            123..124 '1': i32
-            135..136 '1': i32
-            135..136 '1': i32
-            140..144 'foo1': fn foo1(u32) -> isize
-            154..155 '2': i32
-            154..155 '2': i32
-            159..163 'foo2': fn foo2(u32) -> isize
-            173..174 '_': i32
-            178..182 'foo3': fn foo3(u32) -> isize
-        "]],
+fn foo1(x: u32) -> isize { 1 }
+fn foo2(x: u32) -> isize { 2 }
+fn foo3(x: u32) -> isize { 3 }
+fn test() {
+    let x = match 1 {
+        1 => foo1,
+        2 => foo2,
+        _ => foo3,
+    };
+    x;
+  //^ fn(u32) -> isize
+}",
     );
 }
 
 #[test]
 fn coerce_closure_to_fn_ptr() {
-    check_infer_with_mismatches(
+    check_no_mismatches(
         r"
-        fn test() {
-            let f: fn(u32) -> isize = |x| { 1 };
-        }
-        ",
-        expect![[r"
-            10..54 '{     ...1 }; }': ()
-            20..21 'f': fn(u32) -> isize
-            42..51 '|x| { 1 }': |u32| -> isize
-            43..44 'x': u32
-            46..51 '{ 1 }': isize
-            48..49 '1': isize
-        "]],
+fn test() {
+    let f: fn(u32) -> isize = |x| { 1 };
+}",
     );
 }
 
 #[test]
 fn coerce_placeholder_ref() {
     // placeholders should unify, even behind references
-    check_infer_with_mismatches(
+    check_no_mismatches(
         r"
-        struct S<T> { t: T }
-        impl<TT> S<TT> {
-            fn get(&self) -> &TT {
-                &self.t
-            }
-        }
-        ",
-        expect![[r"
-            50..54 'self': &S<TT>
-            63..86 '{     ...     }': &TT
-            73..80 '&self.t': &TT
-            74..78 'self': &S<TT>
-            74..80 'self.t': TT
-        "]],
+struct S<T> { t: T }
+impl<TT> S<TT> {
+    fn get(&self) -> &TT {
+        &self.t
+    }
+}",
     );
 }
 
 #[test]
 fn coerce_unsize_array() {
-    check_infer_with_mismatches(
+    check_types(
         r#"
-        #[lang = "unsize"]
-        pub trait Unsize<T> {}
-        #[lang = "coerce_unsized"]
-        pub trait CoerceUnsized<T> {}
-
-        impl<T: Unsize<U>, U> CoerceUnsized<&U> for &T {}
-
-        fn test() {
-            let f: &[usize] = &[1, 2, 3];
-        }
-        "#,
-        expect![[r#"
-            161..198 '{     ... 3]; }': ()
-            171..172 'f': &[usize]
-            185..195 '&[1, 2, 3]': &[usize; 3]
-            186..195 '[1, 2, 3]': [usize; 3]
-            187..188 '1': usize
-            190..191 '2': usize
-            193..194 '3': usize
-        "#]],
+//- minicore: coerce_unsized
+fn test() {
+    let f: &[usize] = &[1, 2, 3];
+                      //^ usize
+}"#,
     );
 }
 
 #[test]
 fn coerce_unsize_trait_object_simple() {
-    check_infer_with_mismatches(
-        r#"
-        #[lang = "sized"]
-        pub trait Sized {}
-        #[lang = "unsize"]
-        pub trait Unsize<T> {}
-        #[lang = "coerce_unsized"]
-        pub trait CoerceUnsized<T> {}
-
-        impl<T: Unsize<U>, U> CoerceUnsized<&U> for &T {}
-
-        trait Foo<T, U> {}
-        trait Bar<U, T, X>: Foo<T, U> {}
-        trait Baz<T, X>: Bar<usize, T, X> {}
-
-        struct S<T, X>;
-        impl<T, X> Foo<T, usize> for S<T, X> {}
-        impl<T, X> Bar<usize, T, X> for S<T, X> {}
-        impl<T, X> Baz<T, X> for S<T, X> {}
-
-        fn test() {
-            let obj: &dyn Baz<i8, i16> = &S;
-            let obj: &dyn Bar<_, i8, i16> = &S;
-            let obj: &dyn Foo<i8, _> = &S;
-        }
-        "#,
-        expect![[r"
-            424..539 '{     ... &S; }': ()
-            434..437 'obj': &dyn Baz<i8, i16>
-            459..461 '&S': &S<i8, i16>
-            460..461 'S': S<i8, i16>
-            471..474 'obj': &dyn Bar<usize, i8, i16>
-            499..501 '&S': &S<i8, i16>
-            500..501 'S': S<i8, i16>
-            511..514 'obj': &dyn Foo<i8, usize>
-            534..536 '&S': &S<i8, {unknown}>
-            535..536 'S': S<i8, {unknown}>
-        "]],
-    );
-}
-
-#[test]
-// The rust reference says this should be possible, but rustc doesn't implement
-// it. We used to support it, but Chalk doesn't.
-#[ignore]
-fn coerce_unsize_trait_object_to_trait_object() {
-    check_infer_with_mismatches(
+    check_types(
         r#"
-        #[lang = "sized"]
-        pub trait Sized {}
-        #[lang = "unsize"]
-        pub trait Unsize<T> {}
-        #[lang = "coerce_unsized"]
-        pub trait CoerceUnsized<T> {}
-
-        impl<T: Unsize<U>, U> CoerceUnsized<&U> for &T {}
-
-        trait Foo<T, U> {}
-        trait Bar<U, T, X>: Foo<T, U> {}
-        trait Baz<T, X>: Bar<usize, T, X> {}
-
-        struct S<T, X>;
-        impl<T, X> Foo<T, usize> for S<T, X> {}
-        impl<T, X> Bar<usize, T, X> for S<T, X> {}
-        impl<T, X> Baz<T, X> for S<T, X> {}
-
-        fn test() {
-            let obj: &dyn Baz<i8, i16> = &S;
-            let obj: &dyn Bar<_, _, _> = obj;
-            let obj: &dyn Foo<_, _> = obj;
-            let obj2: &dyn Baz<i8, i16> = &S;
-            let _: &dyn Foo<_, _> = obj2;
-        }
-        "#,
-        expect![[r"
-            424..609 '{     ...bj2; }': ()
-            434..437 'obj': &dyn Baz<i8, i16>
-            459..461 '&S': &S<i8, i16>
-            460..461 'S': S<i8, i16>
-            471..474 'obj': &dyn Bar<usize, i8, i16>
-            496..499 'obj': &dyn Baz<i8, i16>
-            509..512 'obj': &dyn Foo<i8, usize>
-            531..534 'obj': &dyn Bar<usize, i8, i16>
-            544..548 'obj2': &dyn Baz<i8, i16>
-            570..572 '&S': &S<i8, i16>
-            571..572 'S': S<i8, i16>
-            582..583 '_': &dyn Foo<i8, usize>
-            602..606 'obj2': &dyn Baz<i8, i16>
-        "]],
+//- minicore: coerce_unsized
+trait Foo<T, U> {}
+trait Bar<U, T, X>: Foo<T, U> {}
+trait Baz<T, X>: Bar<usize, T, X> {}
+
+struct S<T, X>;
+impl<T, X> Foo<T, usize> for S<T, X> {}
+impl<T, X> Bar<usize, T, X> for S<T, X> {}
+impl<T, X> Baz<T, X> for S<T, X> {}
+
+fn test() {
+    let obj: &dyn Baz<i8, i16> = &S;
+                                //^ S<i8, i16>
+    let obj: &dyn Bar<_, i8, i16> = &S;
+                                   //^ S<i8, i16>
+    let obj: &dyn Foo<i8, _> = &S;
+                              //^ S<i8, {unknown}>
+}"#,
     );
 }
 
 #[test]
 fn coerce_unsize_super_trait_cycle() {
-    check_infer_with_mismatches(
+    check_no_mismatches(
         r#"
-        #[lang = "sized"]
-        pub trait Sized {}
-        #[lang = "unsize"]
-        pub trait Unsize<T> {}
-        #[lang = "coerce_unsized"]
-        pub trait CoerceUnsized<T> {}
-
-        impl<T: Unsize<U>, U> CoerceUnsized<&U> for &T {}
-
-        trait A {}
-        trait B: C + A {}
-        trait C: B {}
-        trait D: C
-
-        struct S;
-        impl A for S {}
-        impl B for S {}
-        impl C for S {}
-        impl D for S {}
-
-        fn test() {
-            let obj: &dyn D = &S;
-            let obj: &dyn A = &S;
-        }
-        "#,
-        expect![[r"
-            328..383 '{     ... &S; }': ()
-            338..341 'obj': &dyn D
-            352..354 '&S': &S
-            353..354 'S': S
-            364..367 'obj': &dyn A
-            378..380 '&S': &S
-            379..380 'S': S
-        "]],
+//- minicore: coerce_unsized
+trait A {}
+trait B: C + A {}
+trait C: B {}
+trait D: C
+
+struct S;
+impl A for S {}
+impl B for S {}
+impl C for S {}
+impl D for S {}
+
+fn test() {
+    let obj: &dyn D = &S;
+    let obj: &dyn A = &S;
+}
+"#,
     );
 }
 
 #[test]
 fn coerce_unsize_generic() {
     // FIXME: fix the type mismatches here
-    check_infer_with_mismatches(
+    check(
         r#"
-        #[lang = "unsize"]
-        pub trait Unsize<T> {}
-        #[lang = "coerce_unsized"]
-        pub trait CoerceUnsized<T> {}
-
-        impl<T: Unsize<U>, U> CoerceUnsized<&U> for &T {}
-
-        struct Foo<T> { t: T };
-        struct Bar<T>(Foo<T>);
+//- minicore: coerce_unsized
+struct Foo<T> { t: T };
+struct Bar<T>(Foo<T>);
 
-        fn test() {
-            let _: &Foo<[usize]> = &Foo { t: [1, 2, 3] };
-            let _: &Bar<[usize]> = &Bar(Foo { t: [1, 2, 3] });
-        }
-        "#,
-        expect![[r#"
-            209..317 '{     ... }); }': ()
-            219..220 '_': &Foo<[usize]>
-            238..259 '&Foo {..., 3] }': &Foo<[usize]>
-            239..259 'Foo { ..., 3] }': Foo<[usize]>
-            248..257 '[1, 2, 3]': [usize; 3]
-            249..250 '1': usize
-            252..253 '2': usize
-            255..256 '3': usize
-            269..270 '_': &Bar<[usize]>
-            288..314 '&Bar(F... 3] })': &Bar<[i32; 3]>
-            289..292 'Bar': Bar<[i32; 3]>(Foo<[i32; 3]>) -> Bar<[i32; 3]>
-            289..314 'Bar(Fo... 3] })': Bar<[i32; 3]>
-            293..313 'Foo { ..., 3] }': Foo<[i32; 3]>
-            302..311 '[1, 2, 3]': [i32; 3]
-            303..304 '1': i32
-            306..307 '2': i32
-            309..310 '3': i32
-            248..257: expected [usize], got [usize; 3]
-            288..314: expected &Bar<[usize]>, got &Bar<[i32; 3]>
-        "#]],
+fn test() {
+    let _: &Foo<[usize]> = &Foo { t: [1, 2, 3] };
+                                   //^^^^^^^^^ expected [usize], got [usize; 3]
+    let _: &Bar<[usize]> = &Bar(Foo { t: [1, 2, 3] });
+                         //^^^^^^^^^^^^^^^^^^^^^^^^^^ expected &Bar<[usize]>, got &Bar<[i32; 3]>
+}
+"#,
     );
 }
 
 #[test]
 fn coerce_unsize_apit() {
     // FIXME: #8984
-    check_infer_with_mismatches(
+    check(
         r#"
-#[lang = "sized"]
-pub trait Sized {}
-#[lang = "unsize"]
-pub trait Unsize<T> {}
-#[lang = "coerce_unsized"]
-pub trait CoerceUnsized<T> {}
-
-impl<T: Unsize<U>, U> CoerceUnsized<&U> for &T {}
-
+//- minicore: coerce_unsized
 trait Foo {}
 
 fn test(f: impl Foo) {
     let _: &dyn Foo = &f;
+                    //^^ expected &dyn Foo, got &impl Foo
 }
         "#,
-        expect![[r#"
-            210..211 'f': impl Foo
-            223..252 '{     ... &f; }': ()
-            233..234 '_': &dyn Foo
-            247..249 '&f': &impl Foo
-            248..249 'f': impl Foo
-            247..249: expected &dyn Foo, got &impl Foo
-        "#]],
     );
 }
 
 #[test]
-fn infer_two_closures_lub() {
+fn two_closures_lub() {
     check_types(
         r#"
 fn foo(c: i32) {
     let add = |a: i32, b: i32| a + b;
     let sub = |a, b| a - b;
-            //^ |i32, i32| -> i32
+            //^^^^^^^^^^^^ |i32, i32| -> i32
     if c > 42 { add } else { sub };
-  //^ fn(i32, i32) -> i32
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ fn(i32, i32) -> i32
 }
         "#,
     )
 }
 
 #[test]
-fn infer_match_diverging_branch_1() {
+fn match_diverging_branch_1() {
     check_types(
         r#"
 enum Result<T> { Ok(T), Err }
@@ -942,7 +435,7 @@ fn test() -> i32 {
 }
 
 #[test]
-fn infer_match_diverging_branch_2() {
+fn match_diverging_branch_2() {
     // same as 1 except for order of branches
     check_types(
         r#"
@@ -998,15 +491,7 @@ fn main() {
 fn coerce_unsize_expected_type() {
     check_no_mismatches(
         r#"
-#[lang = "sized"]
-pub trait Sized {}
-#[lang = "unsize"]
-pub trait Unsize<T> {}
-#[lang = "coerce_unsized"]
-pub trait CoerceUnsized<T> {}
-
-impl<T: Unsize<U>, U> CoerceUnsized<&U> for &T {}
-
+//- minicore: coerce_unsized
 fn main() {
     let foo: &[u32] = &[1, 2];
     let foo: &[u32] = match true {
diff --git a/crates/hir_ty/src/tests/display_source_code.rs b/crates/hir_ty/src/tests/display_source_code.rs
index 3d29021aa..058cd02d7 100644
--- a/crates/hir_ty/src/tests/display_source_code.rs
+++ b/crates/hir_ty/src/tests/display_source_code.rs
@@ -10,8 +10,8 @@ mod foo {
 
 fn bar() {
     let foo: foo::Foo = foo::Foo;
-    foo
-}  //^ foo::Foo
+    foo;
+} //^^^ foo::Foo
 
 "#,
     );
@@ -25,7 +25,7 @@ struct Foo<T = u8> { t: T }
 fn main() {
     let foo = Foo { t: 5u8 };
     foo;
-}  //^ Foo
+} //^^^ Foo
 "#,
     );
 
@@ -35,7 +35,7 @@ struct Foo<K, T = u8> { k: K, t: T }
 fn main() {
     let foo = Foo { k: 400, t: 5u8 };
     foo;
-}   //^ Foo<i32>
+} //^^^ Foo<i32>
 "#,
     );
 }
@@ -50,7 +50,7 @@ fn foo() -> *const (impl Unpin + Sized) { loop {} }
 fn main() {
     let foo = foo();
     foo;
-}   //^ *const (impl Unpin + Sized)
+} //^^^ *const (impl Unpin + Sized)
 "#,
     );
 }
diff --git a/crates/hir_ty/src/tests/macros.rs b/crates/hir_ty/src/tests/macros.rs
index d14103aab..2cf41e49e 100644
--- a/crates/hir_ty/src/tests/macros.rs
+++ b/crates/hir_ty/src/tests/macros.rs
@@ -435,11 +435,11 @@ fn processes_impls_generated_by_macros() {
 macro_rules! m {
     ($ident:ident) => (impl Trait for $ident {})
 }
-trait Trait { fn foo(self) -> u128 {} }
+trait Trait { fn foo(self) -> u128 { 0 } }
 struct S;
 m!(S);
 fn test() { S.foo(); }
-                //^ u128
+          //^^^^^^^ u128
 "#,
     );
 }
@@ -457,7 +457,7 @@ impl S {
 }
 
 fn test() { S.foo(); }
-                //^ u128
+          //^^^^^^^ u128
 "#,
     );
 }
@@ -479,7 +479,7 @@ impl S {
 }
 
 fn test() { S.foo(); }
-                //^ u128
+          //^^^^^^^ u128
 "#,
     );
 }
@@ -743,7 +743,7 @@ include!("foo.rs");
 
 fn main() {
     bar();
-}     //^ u32
+} //^^^^^ u32
 
 //- /foo.rs
 fn bar() -> u32 {0}
@@ -781,7 +781,7 @@ include!("f/foo.rs");
 
 fn main() {
     bar::bar();
-}          //^ u32
+} //^^^^^^^^^^ u32
 
 //- /f/foo.rs
 pub mod bar;
@@ -853,7 +853,7 @@ include!("foo.rs");
 
 fn main() {
     RegisterBlock { };
-                  //^ RegisterBlock
+  //^^^^^^^^^^^^^^^^^ RegisterBlock
 }
     "#;
     let fixture = format!("{}\n//- /foo.rs\n{}", fixture, data);
@@ -879,7 +879,7 @@ include!(concat!("f", "oo.rs"));
 
 fn main() {
     bar();
-}     //^ u32
+} //^^^^^ u32
 
 //- /foo.rs
 fn bar() -> u32 {0}
@@ -905,7 +905,7 @@ include!(concat!(env!("OUT_DIR"), "/foo.rs"));
 
 fn main() {
     bar();
-}     //^ {unknown}
+} //^^^^^ {unknown}
 
 //- /foo.rs
 fn bar() -> u32 {0}
@@ -923,7 +923,7 @@ macro_rules! include {() => {}}
 include!("main.rs");
 
 fn main() {
-            0
+    0;
 } //^ i32
 "#,
     );
@@ -979,7 +979,7 @@ fn infer_derive_clone_simple() {
 struct S;
 fn test() {
     S.clone();
-}         //^ S
+} //^^^^^^^^^ S
 
 //- /lib.rs crate:core
 pub mod prelude {
@@ -1028,7 +1028,7 @@ pub struct S;
 use core::S;
 fn test() {
     S.clone();
-}         //^ S
+} //^^^^^^^^^ S
 "#,
     );
 }
@@ -1044,7 +1044,8 @@ struct S;
 struct Wrapper<T>(T);
 struct NonClone;
 fn test() {
-    (Wrapper(S).clone(), Wrapper(NonClone).clone());
+    let x = (Wrapper(S).clone(), Wrapper(NonClone).clone());
+    x;
   //^ (Wrapper<S>, {unknown})
 }
 
@@ -1079,7 +1080,7 @@ struct S{}
 
 fn test() {
     S{};
-}   //^ S
+} //^^^ S
 "#,
     );
 }
diff --git a/crates/hir_ty/src/tests/method_resolution.rs b/crates/hir_ty/src/tests/method_resolution.rs
index f26b2c8a7..3f7a37295 100644
--- a/crates/hir_ty/src/tests/method_resolution.rs
+++ b/crates/hir_ty/src/tests/method_resolution.rs
@@ -257,7 +257,7 @@ fn test() {
 mod foo {
     struct S;
     impl S {
-        fn thing() -> i128 {}
+        fn thing() -> i128 { 0 }
     }
 }
 "#,
@@ -267,164 +267,128 @@ mod foo {
 #[test]
 fn infer_trait_method_simple() {
     // the trait implementation is intentionally incomplete -- it shouldn't matter
-    check_infer(
+    check_types(
         r#"
-        trait Trait1 {
-            fn method(&self) -> u32;
-        }
-        struct S1;
-        impl Trait1 for S1 {}
-        trait Trait2 {
-            fn method(&self) -> i128;
-        }
-        struct S2;
-        impl Trait2 for S2 {}
-        fn test() {
-            S1.method(); // -> u32
-            S2.method(); // -> i128
-        }
+trait Trait1 {
+    fn method(&self) -> u32;
+}
+struct S1;
+impl Trait1 for S1 {}
+trait Trait2 {
+    fn method(&self) -> i128;
+}
+struct S2;
+impl Trait2 for S2 {}
+fn test() {
+    S1.method();
+  //^^^^^^^^^^^ u32
+    S2.method(); // -> i128
+  //^^^^^^^^^^^ i128
+}
         "#,
-        expect![[r#"
-            30..34 'self': &Self
-            109..113 'self': &Self
-            169..227 '{     ...i128 }': ()
-            175..177 'S1': S1
-            175..186 'S1.method()': u32
-            202..204 'S2': S2
-            202..213 'S2.method()': i128
-        "#]],
     );
 }
 
 #[test]
 fn infer_trait_method_scoped() {
     // the trait implementation is intentionally incomplete -- it shouldn't matter
-    check_infer(
+    check_types(
         r#"
-        struct S;
-        mod foo {
-            pub trait Trait1 {
-                fn method(&self) -> u32;
-            }
-            impl Trait1 for super::S {}
-        }
-        mod bar {
-            pub trait Trait2 {
-                fn method(&self) -> i128;
-            }
-            impl Trait2 for super::S {}
-        }
+struct S;
+mod foo {
+    pub trait Trait1 {
+        fn method(&self) -> u32;
+    }
+    impl Trait1 for super::S {}
+}
+mod bar {
+    pub trait Trait2 {
+        fn method(&self) -> i128;
+    }
+    impl Trait2 for super::S {}
+}
 
-        mod foo_test {
-            use super::S;
-            use super::foo::Trait1;
-            fn test() {
-                S.method(); // -> u32
-            }
-        }
+mod foo_test {
+    use super::S;
+    use super::foo::Trait1;
+    fn test() {
+        S.method();
+      //^^^^^^^^^^ u32
+    }
+}
 
-        mod bar_test {
-            use super::S;
-            use super::bar::Trait2;
-            fn test() {
-                S.method(); // -> i128
-            }
-        }
+mod bar_test {
+    use super::S;
+    use super::bar::Trait2;
+    fn test() {
+        S.method();
+      //^^^^^^^^^^ i128
+    }
+}
         "#,
-        expect![[r#"
-            62..66 'self': &Self
-            168..172 'self': &Self
-            299..336 '{     ...     }': ()
-            309..310 'S': S
-            309..319 'S.method()': u32
-            415..453 '{     ...     }': ()
-            425..426 'S': S
-            425..435 'S.method()': i128
-        "#]],
     );
 }
 
 #[test]
 fn infer_trait_method_generic_1() {
     // the trait implementation is intentionally incomplete -- it shouldn't matter
-    check_infer(
+    check_types(
         r#"
-        trait Trait<T> {
-            fn method(&self) -> T;
-        }
-        struct S;
-        impl Trait<u32> for S {}
-        fn test() {
-            S.method();
-        }
+trait Trait<T> {
+    fn method(&self) -> T;
+}
+struct S;
+impl Trait<u32> for S {}
+fn test() {
+    S.method();
+  //^^^^^^^^^^ u32
+}
         "#,
-        expect![[r#"
-            32..36 'self': &Self
-            91..110 '{     ...d(); }': ()
-            97..98 'S': S
-            97..107 'S.method()': u32
-        "#]],
     );
 }
 
 #[test]
 fn infer_trait_method_generic_more_params() {
     // the trait implementation is intentionally incomplete -- it shouldn't matter
-    check_infer(
+    check_types(
         r#"
-        trait Trait<T1, T2, T3> {
-            fn method1(&self) -> (T1, T2, T3);
-            fn method2(&self) -> (T3, T2, T1);
-        }
-        struct S1;
-        impl Trait<u8, u16, u32> for S1 {}
-        struct S2;
-        impl<T> Trait<i8, i16, T> for S2 {}
-        fn test() {
-            S1.method1(); // u8, u16, u32
-            S1.method2(); // u32, u16, u8
-            S2.method1(); // i8, i16, {unknown}
-            S2.method2(); // {unknown}, i16, i8
-        }
+trait Trait<T1, T2, T3> {
+    fn method1(&self) -> (T1, T2, T3);
+    fn method2(&self) -> (T3, T2, T1);
+}
+struct S1;
+impl Trait<u8, u16, u32> for S1 {}
+struct S2;
+impl<T> Trait<i8, i16, T> for S2 {}
+fn test() {
+    S1.method1();
+  //^^^^^^^^^^^^ (u8, u16, u32)
+    S1.method2();
+  //^^^^^^^^^^^^ (u32, u16, u8)
+    S2.method1();
+  //^^^^^^^^^^^^ (i8, i16, {unknown})
+    S2.method2();
+  //^^^^^^^^^^^^ ({unknown}, i16, i8)
+}
         "#,
-        expect![[r#"
-            42..46 'self': &Self
-            81..85 'self': &Self
-            209..360 '{     ..., i8 }': ()
-            215..217 'S1': S1
-            215..227 'S1.method1()': (u8, u16, u32)
-            249..251 'S1': S1
-            249..261 'S1.method2()': (u32, u16, u8)
-            283..285 'S2': S2
-            283..295 'S2.method1()': (i8, i16, {unknown})
-            323..325 'S2': S2
-            323..335 'S2.method2()': ({unknown}, i16, i8)
-        "#]],
     );
 }
 
 #[test]
 fn infer_trait_method_generic_2() {
     // the trait implementation is intentionally incomplete -- it shouldn't matter
-    check_infer(
+    check_types(
         r#"
-        trait Trait<T> {
-            fn method(&self) -> T;
-        }
-        struct S<T>(T);
-        impl<U> Trait<U> for S<U> {}
-        fn test() {
-            S(1u32).method();
-        }
+trait Trait<T> {
+    fn method(&self) -> T;
+}
+struct S<T>(T);
+impl<U> Trait<U> for S<U> {}
+fn test() {
+    S(1u32).method();
+  //^^^^^^^^^^^^^^^^ u32
+}
         "#,
-        expect![[r#"
-            32..36 'self': &Self
-            101..126 '{     ...d(); }': ()
-            107..108 'S': S<u32>(u32) -> S<u32>
-            107..114 'S(1u32)': S<u32>
-            107..123 'S(1u32...thod()': u32
-            109..113 '1u32': u32
-        "#]],
     );
 }
 
@@ -685,10 +649,10 @@ fn method_resolution_unify_impl_self_type() {
     check_types(
         r#"
 struct S<T>;
-impl S<u32> { fn foo(&self) -> u8 {} }
-impl S<i32> { fn foo(&self) -> i8 {} }
+impl S<u32> { fn foo(&self) -> u8 { 0 } }
+impl S<i32> { fn foo(&self) -> i8 { 0 } }
 fn test() { (S::<u32>.foo(), S::<i32>.foo()); }
-          //^ (u8, i8)
+          //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ (u8, i8)
 "#,
     );
 }
@@ -702,7 +666,7 @@ struct S;
 impl S { fn foo(&self) -> i8 { 0 } }
 impl Trait for S { fn foo(self) -> u128 { 0 } }
 fn test() { S.foo(); }
-                //^ u128
+          //^^^^^^^ u128
 "#,
     );
 }
@@ -716,7 +680,7 @@ struct S;
 impl Clone for S {}
 impl Clone for &S {}
 fn test() { (S.clone(), (&S).clone(), (&&S).clone()); }
-          //^ (S, S, &S)
+          //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ (S, S, &S)
 "#,
     );
 }
@@ -730,7 +694,7 @@ struct S;
 impl S { fn foo(self) -> i8 { 0 } }
 impl Trait for &S { fn foo(self) -> u128 { 0 } }
 fn test() { (&S).foo(); }
-                   //^ u128
+          //^^^^^^^^^^ u128
 "#,
     );
 }
@@ -744,7 +708,7 @@ struct S;
 impl S { fn foo(self) -> i8 { 0 } }
 impl Trait for S { fn foo(self) -> u128 { 0 } }
 fn test() { S.foo(); }
-                //^ i8
+          //^^^^^^^ i8
 "#,
     );
 }
@@ -758,7 +722,7 @@ struct S;
 impl S { fn foo(&self) -> i8 { 0 } }
 impl Trait for &S { fn foo(self) -> u128 { 0 } }
 fn test() { S.foo(); }
-                //^ i8
+          //^^^^^^^ i8
 "#,
     );
 }
@@ -771,7 +735,7 @@ trait Trait { fn foo(self) -> u128; }
 struct S;
 impl Trait for S { fn foo(self) -> u128 { 0 } }
 fn test() { (&S).foo(); }
-                   //^ u128
+          //^^^^^^^^^^ u128
 "#,
     );
 }
@@ -780,14 +744,11 @@ fn test() { (&S).foo(); }
 fn method_resolution_unsize_array() {
     check_types(
         r#"
-#[lang = "slice"]
-impl<T> [T] {
-    fn len(&self) -> usize { loop {} }
-}
+//- minicore: slice
 fn test() {
     let a = [1, 2, 3];
     a.len();
-}       //^ usize
+} //^^^^^^^ usize
 "#,
     );
 }
@@ -802,7 +763,7 @@ impl Clone for S {}
 
 fn test() {
     S.clone();
-          //^ S
+  //^^^^^^^^^ S
 }
 
 //- /lib.rs crate:core
@@ -826,7 +787,7 @@ trait Trait { fn foo(self) -> u128; }
 struct S;
 impl<T> Trait for T where T: UnknownTrait {}
 fn test() { (&S).foo(); }
-                   //^ u128
+          //^^^^^^^^^^ u128
 "#,
     );
 }
@@ -844,7 +805,7 @@ trait Trait { fn foo(self) -> u128; }
 struct S;
 impl<T> Trait for T where T: Clone {}
 fn test() { (&S).foo(); }
-                   //^ {unknown}
+          //^^^^^^^^^^ {unknown}
 "#,
     );
 }
@@ -859,7 +820,7 @@ trait Trait { fn foo(self) -> u128; }
 struct S;
 impl<T: Clone> Trait for T {}
 fn test() { (&S).foo(); }
-                   //^ {unknown}
+          //^^^^^^^^^^ {unknown}
 "#,
     );
 }
@@ -874,7 +835,7 @@ struct S;
 impl Clone for S {}
 impl<T> Trait for T where T: Clone {}
 fn test() { S.foo(); }
-                //^ u128
+          //^^^^^^^ u128
 "#,
     );
 }
@@ -890,7 +851,7 @@ struct S2;
 impl From<S2> for S1 {}
 impl<T, U> Into<U> for T where U: From<T> {}
 fn test() { S2.into(); }
-                  //^ {unknown}
+          //^^^^^^^^^ {unknown}
 "#,
     );
 }
@@ -906,7 +867,7 @@ struct S2;
 impl From<S2> for S1 {}
 impl<T, U: From<T>> Into<U> for T {}
 fn test() { S2.into(); }
-                  //^ {unknown}
+          //^^^^^^^^^ {unknown}
 "#,
     );
 }
@@ -936,7 +897,7 @@ fn main() {
     let a = Wrapper::<Foo<f32>>::new(1.0);
     let b = Wrapper::<Bar<f32>>::new(1.0);
     (a, b);
-  //^ (Wrapper<Foo<f32>>, Wrapper<Bar<f32>>)
+  //^^^^^^ (Wrapper<Foo<f32>>, Wrapper<Bar<f32>>)
 }
 "#,
     );
@@ -950,7 +911,7 @@ fn method_resolution_encountering_fn_type() {
 fn foo() {}
 trait FnOnce { fn call(self); }
 fn test() { foo.call(); }
-                   //^ {unknown}
+          //^^^^^^^^^^ {unknown}
 "#,
     );
 }
@@ -1016,7 +977,7 @@ where
     Wrapper<T>: a::Foo,
 {
     t.foo();
-}       //^ {unknown}
+} //^^^^^^^ {unknown}
 "#,
     );
 }
@@ -1033,7 +994,7 @@ impl A<i32> {
 
 fn main() {
     A::from(3);
-}          //^ A<i32>
+} //^^^^^^^^^^ A<i32>
 "#,
     );
 }
@@ -1061,7 +1022,7 @@ trait FnX {}
 impl<B, C> Trait for S<B, C> where C: FnX, B: SendX {}
 
 fn test() { (S {}).method(); }
-                        //^ ()
+          //^^^^^^^^^^^^^^^ ()
 "#,
     );
 }
@@ -1146,8 +1107,8 @@ impl<T> Slice<T> {
 
 fn main() {
     let foo: Slice<u32>;
-    (foo.into_vec()); // we don't actually support arbitrary self types, but we shouldn't crash at least
-} //^ {unknown}
+    foo.into_vec(); // we shouldn't crash on this at least
+} //^^^^^^^^^^^^^^ {unknown}
 "#,
     );
 }
@@ -1168,7 +1129,7 @@ impl dyn Foo + '_ {
 fn main() {
     let f = &42u32 as &dyn Foo;
     f.dyn_foo();
-  // ^u32
+ // ^^^^^^^^^^^ u32
 }
 "#,
     );
@@ -1178,11 +1139,7 @@ fn main() {
 fn autoderef_visibility_field() {
     check_infer(
         r#"
-#[lang = "deref"]
-pub trait Deref {
-    type Target;
-    fn deref(&self) -> &Self::Target;
-}
+//- minicore: deref
 mod a {
     pub struct Foo(pub char);
     pub struct Bar(i32);
@@ -1191,7 +1148,7 @@ mod a {
             Self(0)
         }
     }
-    impl super::Deref for Bar {
+    impl core::ops::Deref for Bar {
         type Target = Foo;
         fn deref(&self) -> &Foo {
             &Foo('z')
@@ -1205,22 +1162,21 @@ mod b {
 }
         "#,
         expect![[r#"
-            67..71 'self': &Self
-            200..231 '{     ...     }': Bar
-            214..218 'Self': Bar(i32) -> Bar
-            214..221 'Self(0)': Bar
-            219..220 '0': i32
-            315..319 'self': &Bar
-            329..362 '{     ...     }': &Foo
-            343..352 '&Foo('z')': &Foo
-            344..347 'Foo': Foo(char) -> Foo
-            344..352 'Foo('z')': Foo
-            348..351 ''z'': char
-            392..439 '{     ...     }': ()
-            406..407 'x': char
-            410..428 'super:...r::new': fn new() -> Bar
-            410..430 'super:...:new()': Bar
-            410..432 'super:...ew().0': char
+            107..138 '{     ...     }': Bar
+            121..125 'Self': Bar(i32) -> Bar
+            121..128 'Self(0)': Bar
+            126..127 '0': i32
+            226..230 'self': &Bar
+            240..273 '{     ...     }': &Foo
+            254..263 '&Foo('z')': &Foo
+            255..258 'Foo': Foo(char) -> Foo
+            255..263 'Foo('z')': Foo
+            259..262 ''z'': char
+            303..350 '{     ...     }': ()
+            317..318 'x': char
+            321..339 'super:...r::new': fn new() -> Bar
+            321..341 'super:...:new()': Bar
+            321..343 'super:...ew().0': char
         "#]],
     )
 }
@@ -1230,11 +1186,7 @@ fn autoderef_visibility_method() {
     cov_mark::check!(autoderef_candidate_not_visible);
     check_infer(
         r#"
-#[lang = "deref"]
-pub trait Deref {
-    type Target;
-    fn deref(&self) -> &Self::Target;
-}
+//- minicore: deref
 mod a {
     pub struct Foo(pub char);
     impl Foo {
@@ -1251,7 +1203,7 @@ mod a {
             self.0
         }
     }
-    impl super::Deref for Bar {
+    impl core::ops::Deref for Bar {
         type Target = Foo;
         fn deref(&self) -> &Foo {
             &Foo('z')
@@ -1265,30 +1217,29 @@ mod b {
 }
         "#,
         expect![[r#"
-            67..71 'self': &Self
-            168..172 'self': &Foo
-            182..212 '{     ...     }': char
-            196..200 'self': &Foo
-            196..202 'self.0': char
-            288..319 '{     ...     }': Bar
-            302..306 'Self': Bar(i32) -> Bar
-            302..309 'Self(0)': Bar
-            307..308 '0': i32
-            338..342 'self': &Bar
-            351..381 '{     ...     }': i32
-            365..369 'self': &Bar
-            365..371 'self.0': i32
-            465..469 'self': &Bar
-            479..512 '{     ...     }': &Foo
-            493..502 '&Foo('z')': &Foo
-            494..497 'Foo': Foo(char) -> Foo
-            494..502 'Foo('z')': Foo
-            498..501 ''z'': char
-            542..595 '{     ...     }': ()
-            556..557 'x': char
-            560..578 'super:...r::new': fn new() -> Bar
-            560..580 'super:...:new()': Bar
-            560..588 'super:...ango()': char
+            75..79 'self': &Foo
+            89..119 '{     ...     }': char
+            103..107 'self': &Foo
+            103..109 'self.0': char
+            195..226 '{     ...     }': Bar
+            209..213 'Self': Bar(i32) -> Bar
+            209..216 'Self(0)': Bar
+            214..215 '0': i32
+            245..249 'self': &Bar
+            258..288 '{     ...     }': i32
+            272..276 'self': &Bar
+            272..278 'self.0': i32
+            376..380 'self': &Bar
+            390..423 '{     ...     }': &Foo
+            404..413 '&Foo('z')': &Foo
+            405..408 'Foo': Foo(char) -> Foo
+            405..413 'Foo('z')': Foo
+            409..412 ''z'': char
+            453..506 '{     ...     }': ()
+            467..468 'x': char
+            471..489 'super:...r::new': fn new() -> Bar
+            471..491 'super:...:new()': Bar
+            471..499 'super:...ango()': char
         "#]],
     )
 }
@@ -1389,11 +1340,11 @@ pub trait IntoIterator {
 
 impl<T> IntoIterator for [T; 1] {
     type Out = T;
-    fn into_iter(self) -> Self::Out {}
+    fn into_iter(self) -> Self::Out { loop {} }
 }
 impl<'a, T> IntoIterator for &'a [T] {
     type Out = &'a T;
-    fn into_iter(self) -> Self::Out {}
+    fn into_iter(self) -> Self::Out { loop {} }
 }
     "#,
     );
diff --git a/crates/hir_ty/src/tests/patterns.rs b/crates/hir_ty/src/tests/patterns.rs
index aa513c56d..47aa30d2e 100644
--- a/crates/hir_ty/src/tests/patterns.rs
+++ b/crates/hir_ty/src/tests/patterns.rs
@@ -1,6 +1,6 @@
 use expect_test::expect;
 
-use super::{check_infer, check_infer_with_mismatches, check_mismatches, check_types};
+use super::{check, check_infer, check_infer_with_mismatches, check_types};
 
 #[test]
 fn infer_pattern() {
@@ -518,7 +518,7 @@ fn infer_generics_in_patterns() {
 
 #[test]
 fn infer_const_pattern() {
-    check_mismatches(
+    check(
         r#"
 enum Option<T> { None }
 use Option::None;
@@ -571,48 +571,44 @@ fn main() {
 fn match_ergonomics_in_closure_params() {
     check_infer(
         r#"
-        #[lang = "fn_once"]
-        trait FnOnce<Args> {
-            type Output;
-        }
-
-        fn foo<T, U, F: FnOnce(T) -> U>(t: T, f: F) -> U { loop {} }
+//- minicore: fn
+fn foo<T, U, F: FnOnce(T) -> U>(t: T, f: F) -> U { loop {} }
 
-        fn test() {
-            foo(&(1, "a"), |&(x, y)| x); // normal, no match ergonomics
-            foo(&(1, "a"), |(x, y)| x);
-        }
-        "#,
+fn test() {
+    foo(&(1, "a"), |&(x, y)| x); // normal, no match ergonomics
+    foo(&(1, "a"), |(x, y)| x);
+}
+"#,
         expect![[r#"
-            93..94 't': T
-            99..100 'f': F
-            110..121 '{ loop {} }': U
-            112..119 'loop {}': !
-            117..119 '{}': ()
-            133..232 '{     ... x); }': ()
-            139..142 'foo': fn foo<&(i32, &str), i32, |&(i32, &str)| -> i32>(&(i32, &str), |&(i32, &str)| -> i32) -> i32
-            139..166 'foo(&(...y)| x)': i32
-            143..152 '&(1, "a")': &(i32, &str)
-            144..152 '(1, "a")': (i32, &str)
-            145..146 '1': i32
-            148..151 '"a"': &str
-            154..165 '|&(x, y)| x': |&(i32, &str)| -> i32
-            155..162 '&(x, y)': &(i32, &str)
-            156..162 '(x, y)': (i32, &str)
-            157..158 'x': i32
-            160..161 'y': &str
-            164..165 'x': i32
-            203..206 'foo': fn foo<&(i32, &str), &i32, |&(i32, &str)| -> &i32>(&(i32, &str), |&(i32, &str)| -> &i32) -> &i32
-            203..229 'foo(&(...y)| x)': &i32
-            207..216 '&(1, "a")': &(i32, &str)
-            208..216 '(1, "a")': (i32, &str)
-            209..210 '1': i32
-            212..215 '"a"': &str
-            218..228 '|(x, y)| x': |&(i32, &str)| -> &i32
-            219..225 '(x, y)': (i32, &str)
-            220..221 'x': &i32
-            223..224 'y': &&str
-            227..228 'x': &i32
+            32..33 't': T
+            38..39 'f': F
+            49..60 '{ loop {} }': U
+            51..58 'loop {}': !
+            56..58 '{}': ()
+            72..171 '{     ... x); }': ()
+            78..81 'foo': fn foo<&(i32, &str), i32, |&(i32, &str)| -> i32>(&(i32, &str), |&(i32, &str)| -> i32) -> i32
+            78..105 'foo(&(...y)| x)': i32
+            82..91 '&(1, "a")': &(i32, &str)
+            83..91 '(1, "a")': (i32, &str)
+            84..85 '1': i32
+            87..90 '"a"': &str
+            93..104 '|&(x, y)| x': |&(i32, &str)| -> i32
+            94..101 '&(x, y)': &(i32, &str)
+            95..101 '(x, y)': (i32, &str)
+            96..97 'x': i32
+            99..100 'y': &str
+            103..104 'x': i32
+            142..145 'foo': fn foo<&(i32, &str), &i32, |&(i32, &str)| -> &i32>(&(i32, &str), |&(i32, &str)| -> &i32) -> &i32
+            142..168 'foo(&(...y)| x)': &i32
+            146..155 '&(1, "a")': &(i32, &str)
+            147..155 '(1, "a")': (i32, &str)
+            148..149 '1': i32
+            151..154 '"a"': &str
+            157..167 '|(x, y)| x': |&(i32, &str)| -> &i32
+            158..164 '(x, y)': (i32, &str)
+            159..160 'x': &i32
+            162..163 'y': &&str
+            166..167 'x': &i32
         "#]],
     );
 }
diff --git a/crates/hir_ty/src/tests/regression.rs b/crates/hir_ty/src/tests/regression.rs
index 1019e783b..8c5e8954c 100644
--- a/crates/hir_ty/src/tests/regression.rs
+++ b/crates/hir_ty/src/tests/regression.rs
@@ -1,6 +1,6 @@
 use expect_test::expect;
 
-use super::{check_infer, check_types};
+use super::{check_infer, check_no_mismatches, check_types};
 
 #[test]
 fn bug_484() {
@@ -418,55 +418,24 @@ fn issue_2705() {
 fn issue_2683_chars_impl() {
     check_types(
         r#"
-//- /main.rs crate:main deps:std
-fn test() {
-    let chars: std::str::Chars<'_>;
-    (chars.next(), chars.nth(1));
-} //^ (Option<char>, Option<char>)
-
-//- /std.rs crate:std
-#[prelude_import]
-use self::prelude::rust_2018::*;
-pub mod prelude {
-    pub mod rust_2018 {
-        pub use crate::iter::Iterator;
-        pub use crate::option::Option;
-    }
+//- minicore: iterator
+pub struct Chars<'a> {}
+impl<'a> Iterator for Chars<'a> {
+    type Item = char;
+    fn next(&mut self) -> Option<char> { loop {} }
 }
 
-pub mod iter {
-    pub use self::traits::Iterator;
-    pub mod traits {
-        pub use self::iterator::Iterator;
-
-        pub mod iterator {
-            pub trait Iterator {
-                type Item;
-                fn next(&mut self) -> Option<Self::Item>;
-                fn nth(&mut self, n: usize) -> Option<Self::Item> {}
-            }
-        }
-    }
-}
-
-pub mod option {
-    pub enum Option<T> {}
-}
-
-pub mod str {
-    pub struct Chars<'a> {}
-    impl<'a> Iterator for Chars<'a> {
-        type Item = char;
-        fn next(&mut self) -> Option<char> {}
-    }
-}
+fn test() {
+    let chars: Chars<'_>;
+    (chars.next(), chars.nth(1));
+} //^^^^^^^^^^^^^^^^^^^^^^^^^^^^ (Option<char>, Option<char>)
 "#,
     );
 }
 
 #[test]
 fn issue_3642_bad_macro_stackover() {
-    check_types(
+    check_no_mismatches(
         r#"
 #[macro_export]
 macro_rules! match_ast {
@@ -483,7 +452,6 @@ macro_rules! match_ast {
 
 fn main() {
     let anchor = match_ast! {
-       //^ ()
         match parent {
             as => {},
             _ => return None
@@ -736,12 +704,8 @@ fn issue_4931() {
 fn issue_4885() {
     check_infer(
         r#"
-        #[lang = "coerce_unsized"]
-        pub trait CoerceUnsized<T> {}
-
-        trait Future {
-            type Output;
-        }
+        //- minicore: coerce_unsized, future
+        use core::future::Future;
         trait Foo<R> {
             type Bar;
         }
@@ -758,13 +722,13 @@ fn issue_4885() {
         }
         "#,
         expect![[r#"
-            136..139 'key': &K
-            198..214 '{     ...key) }': impl Future<Output = <K as Foo<R>>::Bar>
-            204..207 'bar': fn bar<R, K>(&K) -> impl Future<Output = <K as Foo<R>>::Bar>
-            204..212 'bar(key)': impl Future<Output = <K as Foo<R>>::Bar>
-            208..211 'key': &K
-            228..231 'key': &K
-            290..293 '{ }': ()
+            70..73 'key': &K
+            132..148 '{     ...key) }': impl Future<Output = <K as Foo<R>>::Bar>
+            138..141 'bar': fn bar<R, K>(&K) -> impl Future<Output = <K as Foo<R>>::Bar>
+            138..146 'bar(key)': impl Future<Output = <K as Foo<R>>::Bar>
+            142..145 'key': &K
+            162..165 'key': &K
+            224..227 '{ }': ()
         "#]],
     );
 }
@@ -827,6 +791,7 @@ fn issue_4800() {
 fn issue_4966() {
     check_infer(
         r#"
+        //- minicore: deref
         pub trait IntoIterator {
             type Item;
         }
@@ -837,12 +802,7 @@ fn issue_4966() {
 
         struct Vec<T> {}
 
-        #[lang = "deref"]
-        pub trait Deref {
-            type Target;
-        }
-
-        impl<T> Deref for Vec<T> {
+        impl<T> core::ops::Deref for Vec<T> {
             type Target = [T];
         }
 
@@ -859,23 +819,23 @@ fn issue_4966() {
         }
         "#,
         expect![[r#"
-            270..274 'iter': T
-            289..291 '{}': ()
-            303..447 '{     ...r(); }': ()
-            313..318 'inner': Map<|&f64| -> f64>
-            321..345 'Map { ... 0.0 }': Map<|&f64| -> f64>
-            330..343 '|_: &f64| 0.0': |&f64| -> f64
-            331..332 '_': &f64
-            340..343 '0.0': f64
-            356..362 'repeat': Repeat<Map<|&f64| -> f64>>
-            365..390 'Repeat...nner }': Repeat<Map<|&f64| -> f64>>
-            383..388 'inner': Map<|&f64| -> f64>
-            401..404 'vec': Vec<IntoIterator::Item<Repeat<Map<|&f64| -> f64>>>>
-            407..416 'from_iter': fn from_iter<IntoIterator::Item<Repeat<Map<|&f64| -> f64>>>, Repeat<Map<|&f64| -> f64>>>(Repeat<Map<|&f64| -> f64>>) -> Vec<IntoIterator::Item<Repeat<Map<|&f64| -> f64>>>>
-            407..424 'from_i...epeat)': Vec<IntoIterator::Item<Repeat<Map<|&f64| -> f64>>>>
-            417..423 'repeat': Repeat<Map<|&f64| -> f64>>
-            431..434 'vec': Vec<IntoIterator::Item<Repeat<Map<|&f64| -> f64>>>>
-            431..444 'vec.foo_bar()': {unknown}
+            225..229 'iter': T
+            244..246 '{}': ()
+            258..402 '{     ...r(); }': ()
+            268..273 'inner': Map<|&f64| -> f64>
+            276..300 'Map { ... 0.0 }': Map<|&f64| -> f64>
+            285..298 '|_: &f64| 0.0': |&f64| -> f64
+            286..287 '_': &f64
+            295..298 '0.0': f64
+            311..317 'repeat': Repeat<Map<|&f64| -> f64>>
+            320..345 'Repeat...nner }': Repeat<Map<|&f64| -> f64>>
+            338..343 'inner': Map<|&f64| -> f64>
+            356..359 'vec': Vec<IntoIterator::Item<Repeat<Map<|&f64| -> f64>>>>
+            362..371 'from_iter': fn from_iter<IntoIterator::Item<Repeat<Map<|&f64| -> f64>>>, Repeat<Map<|&f64| -> f64>>>(Repeat<Map<|&f64| -> f64>>) -> Vec<IntoIterator::Item<Repeat<Map<|&f64| -> f64>>>>
+            362..379 'from_i...epeat)': Vec<IntoIterator::Item<Repeat<Map<|&f64| -> f64>>>>
+            372..378 'repeat': Repeat<Map<|&f64| -> f64>>
+            386..389 'vec': Vec<IntoIterator::Item<Repeat<Map<|&f64| -> f64>>>>
+            386..399 'vec.foo_bar()': {unknown}
         "#]],
     );
 }
@@ -884,41 +844,37 @@ fn issue_4966() {
 fn issue_6628() {
     check_infer(
         r#"
-        #[lang = "fn_once"]
-        pub trait FnOnce<Args> {
-            type Output;
-        }
-
-        struct S<T>();
-        impl<T> S<T> {
-            fn f(&self, _t: T) {}
-            fn g<F: FnOnce(&T)>(&self, _f: F) {}
-        }
-        fn main() {
-            let s = S();
-            s.g(|_x| {});
-            s.f(10);
-        }
-        "#,
+//- minicore: fn
+struct S<T>();
+impl<T> S<T> {
+    fn f(&self, _t: T) {}
+    fn g<F: FnOnce(&T)>(&self, _f: F) {}
+}
+fn main() {
+    let s = S();
+    s.g(|_x| {});
+    s.f(10);
+}
+"#,
         expect![[r#"
-            105..109 'self': &S<T>
-            111..113 '_t': T
-            118..120 '{}': ()
-            146..150 'self': &S<T>
-            152..154 '_f': F
-            159..161 '{}': ()
-            174..225 '{     ...10); }': ()
-            184..185 's': S<i32>
-            188..189 'S': S<i32>() -> S<i32>
-            188..191 'S()': S<i32>
-            197..198 's': S<i32>
-            197..209 's.g(|_x| {})': ()
-            201..208 '|_x| {}': |&i32| -> ()
-            202..204 '_x': &i32
-            206..208 '{}': ()
-            215..216 's': S<i32>
-            215..222 's.f(10)': ()
-            219..221 '10': i32
+            40..44 'self': &S<T>
+            46..48 '_t': T
+            53..55 '{}': ()
+            81..85 'self': &S<T>
+            87..89 '_f': F
+            94..96 '{}': ()
+            109..160 '{     ...10); }': ()
+            119..120 's': S<i32>
+            123..124 'S': S<i32>() -> S<i32>
+            123..126 'S()': S<i32>
+            132..133 's': S<i32>
+            132..144 's.g(|_x| {})': ()
+            136..143 '|_x| {}': |&i32| -> ()
+            137..139 '_x': &i32
+            141..143 '{}': ()
+            150..151 's': S<i32>
+            150..157 's.f(10)': ()
+            154..156 '10': i32
         "#]],
     );
 }
@@ -927,35 +883,33 @@ fn issue_6628() {
 fn issue_6852() {
     check_infer(
         r#"
-        #[lang = "deref"]
-        pub trait Deref {
-            type Target;
-        }
+//- minicore: deref
+use core::ops::Deref;
 
-        struct BufWriter {}
+struct BufWriter {}
 
-        struct Mutex<T> {}
-        struct MutexGuard<'a, T> {}
-        impl<T> Mutex<T> {
-            fn lock(&self) -> MutexGuard<'_, T> {}
-        }
-        impl<'a, T: 'a> Deref for MutexGuard<'a, T> {
-            type Target = T;
-        }
-        fn flush(&self) {
-            let w: &Mutex<BufWriter>;
-            *(w.lock());
-        }
-        "#,
+struct Mutex<T> {}
+struct MutexGuard<'a, T> {}
+impl<T> Mutex<T> {
+    fn lock(&self) -> MutexGuard<'_, T> {}
+}
+impl<'a, T: 'a> Deref for MutexGuard<'a, T> {
+    type Target = T;
+}
+fn flush(&self) {
+    let w: &Mutex<BufWriter>;
+    *(w.lock());
+}
+"#,
         expect![[r#"
-            156..160 'self': &Mutex<T>
-            183..185 '{}': ()
-            267..271 'self': &{unknown}
-            273..323 '{     ...()); }': ()
-            283..284 'w': &Mutex<BufWriter>
-            309..320 '*(w.lock())': BufWriter
-            311..312 'w': &Mutex<BufWriter>
-            311..319 'w.lock()': MutexGuard<BufWriter>
+            123..127 'self': &Mutex<T>
+            150..152 '{}': ()
+            234..238 'self': &{unknown}
+            240..290 '{     ...()); }': ()
+            250..251 'w': &Mutex<BufWriter>
+            276..287 '*(w.lock())': BufWriter
+            278..279 'w': &Mutex<BufWriter>
+            278..286 'w.lock()': MutexGuard<BufWriter>
         "#]],
     );
 }
@@ -977,37 +931,33 @@ fn param_overrides_fn() {
 fn lifetime_from_chalk_during_deref() {
     check_types(
         r#"
-        #[lang = "deref"]
-        pub trait Deref {
-            type Target;
-        }
-
-        struct Box<T: ?Sized> {}
-        impl<T> Deref for Box<T> {
-            type Target = T;
+//- minicore: deref
+struct Box<T: ?Sized> {}
+impl<T> core::ops::Deref for Box<T> {
+    type Target = T;
 
-            fn deref(&self) -> &Self::Target {
-                loop {}
-            }
-        }
+    fn deref(&self) -> &Self::Target {
+        loop {}
+    }
+}
 
-        trait Iterator {
-            type Item;
-        }
+trait Iterator {
+    type Item;
+}
 
-        pub struct Iter<'a, T: 'a> {
-            inner: Box<dyn IterTrait<'a, T, Item = &'a T> + 'a>,
-        }
+pub struct Iter<'a, T: 'a> {
+    inner: Box<dyn IterTrait<'a, T, Item = &'a T> + 'a>,
+}
 
-        trait IterTrait<'a, T: 'a>: Iterator<Item = &'a T> {
-            fn clone_box(&self);
-        }
+trait IterTrait<'a, T: 'a>: Iterator<Item = &'a T> {
+    fn clone_box(&self);
+}
 
-        fn clone_iter<T>(s: Iter<T>) {
-            s.inner.clone_box();
-          //^^^^^^^^^^^^^^^^^^^ ()
-        }
-        "#,
+fn clone_iter<T>(s: Iter<T>) {
+    s.inner.clone_box();
+  //^^^^^^^^^^^^^^^^^^^ ()
+}
+"#,
     )
 }
 
diff --git a/crates/hir_ty/src/tests/simple.rs b/crates/hir_ty/src/tests/simple.rs
index 3418ed21e..b4bcc6d95 100644
--- a/crates/hir_ty/src/tests/simple.rs
+++ b/crates/hir_ty/src/tests/simple.rs
@@ -60,7 +60,7 @@ enum Nat { Succ(Self), Demo(Nat), Zero }
 fn test() {
     let foo: Nat = Nat::Zero;
     if let Nat::Succ(x) = foo {
-        x
+        x;
     } //^ Nat
 }
 "#,
@@ -113,7 +113,7 @@ fn type_alias_in_struct_lit() {
 fn infer_ranges() {
     check_types(
         r#"
-//- /main.rs crate:main deps:core
+//- minicore: range
 fn test() {
     let a = ..;
     let b = 1..;
@@ -125,32 +125,6 @@ fn test() {
     let t = (a, b, c, d, e, f);
     t;
 } //^ (RangeFull, RangeFrom<i32>, RangeTo<u32>, Range<usize>, RangeToInclusive<i32>, RangeInclusive<char>)
-
-//- /core.rs crate:core
-#[prelude_import] use prelude::*;
-mod prelude {}
-
-pub mod ops {
-    pub struct Range<Idx> {
-        pub start: Idx,
-        pub end: Idx,
-    }
-    pub struct RangeFrom<Idx> {
-        pub start: Idx,
-    }
-    struct RangeFull;
-    pub struct RangeInclusive<Idx> {
-        start: Idx,
-        end: Idx,
-        is_empty: u8,
-    }
-    pub struct RangeTo<Idx> {
-        pub end: Idx,
-    }
-    pub struct RangeToInclusive<Idx> {
-        pub end: Idx,
-    }
-}
 "#,
     );
 }
@@ -164,7 +138,7 @@ enum Option<T> { Some(T), None }
 fn test() {
     let foo: Option<f32> = None;
     while let Option::Some(x) = foo {
-        x
+        x;
     } //^ f32
 }
 "#,
@@ -175,16 +149,17 @@ fn test() {
 fn infer_basics() {
     check_infer(
         r#"
-        fn test(a: u32, b: isize, c: !, d: &str) {
-            a;
-            b;
-            c;
-            d;
-            1usize;
-            1isize;
-            "test";
-            1.0f32;
-        }"#,
+fn test(a: u32, b: isize, c: !, d: &str) {
+    a;
+    b;
+    c;
+    d;
+    1usize;
+    1isize;
+    "test";
+    1.0f32;
+}
+"#,
         expect![[r#"
             8..9 'a': u32
             16..17 'b': isize
@@ -207,15 +182,15 @@ fn infer_basics() {
 fn infer_let() {
     check_infer(
         r#"
-        fn test() {
-            let a = 1isize;
-            let b: usize = 1;
-            let c = b;
-            let d: u32;
-            let e;
-            let f: i32 = e;
-        }
-        "#,
+fn test() {
+    let a = 1isize;
+    let b: usize = 1;
+    let c = b;
+    let d: u32;
+    let e;
+    let f: i32 = e;
+}
+"#,
         expect![[r#"
             10..117 '{     ...= e; }': ()
             20..21 'a': isize
@@ -236,17 +211,17 @@ fn infer_let() {
 fn infer_paths() {
     check_infer(
         r#"
-        fn a() -> u32 { 1 }
+fn a() -> u32 { 1 }
 
-        mod b {
-            fn c() -> u32 { 1 }
-        }
+mod b {
+    fn c() -> u32 { 1 }
+}
 
-        fn test() {
-            a();
-            b::c();
-        }
-        "#,
+fn test() {
+    a();
+    b::c();
+}
+"#,
         expect![[r#"
             14..19 '{ 1 }': u32
             16..17 '1': u32
@@ -265,17 +240,17 @@ fn infer_paths() {
 fn infer_path_type() {
     check_infer(
         r#"
-        struct S;
+struct S;
 
-        impl S {
-            fn foo() -> i32 { 1 }
-        }
+impl S {
+    fn foo() -> i32 { 1 }
+}
 
-        fn test() {
-            S::foo();
-            <S>::foo();
-        }
-        "#,
+fn test() {
+    S::foo();
+    <S>::foo();
+}
+"#,
         expect![[r#"
             40..45 '{ 1 }': i32
             42..43 '1': i32
@@ -292,21 +267,21 @@ fn infer_path_type() {
 fn infer_struct() {
     check_infer(
         r#"
-        struct A {
-            b: B,
-            c: C,
-        }
-        struct B;
-        struct C(usize);
+struct A {
+    b: B,
+    c: C,
+}
+struct B;
+struct C(usize);
 
-        fn test() {
-            let c = C(1);
-            B;
-            let a: A = A { b: B, c: C(1) };
-            a.b;
-            a.c;
-        }
-        "#,
+fn test() {
+    let c = C(1);
+    B;
+    let a: A = A { b: B, c: C(1) };
+    a.b;
+    a.c;
+}
+"#,
         expect![[r#"
             71..153 '{     ...a.c; }': ()
             81..82 'c': C
@@ -332,14 +307,15 @@ fn infer_struct() {
 fn infer_enum() {
     check_infer(
         r#"
-        enum E {
-            V1 { field: u32 },
-            V2
-        }
-        fn test() {
-            E::V1 { field: 1 };
-            E::V2;
-        }"#,
+enum E {
+    V1 { field: u32 },
+    V2
+}
+fn test() {
+    E::V1 { field: 1 };
+    E::V2;
+}
+"#,
         expect![[r#"
             51..89 '{     ...:V2; }': ()
             57..75 'E::V1 ...d: 1 }': E
@@ -353,23 +329,23 @@ fn infer_enum() {
 fn infer_union() {
     check_infer(
         r#"
-        union MyUnion {
-            foo: u32,
-            bar: f32,
-        }
+union MyUnion {
+    foo: u32,
+    bar: f32,
+}
 
-        fn test() {
-            let u = MyUnion { foo: 0 };
-            unsafe { baz(u); }
-            let u = MyUnion { bar: 0.0 };
-            unsafe { baz(u); }
-        }
+fn test() {
+    let u = MyUnion { foo: 0 };
+    unsafe { baz(u); }
+    let u = MyUnion { bar: 0.0 };
+    unsafe { baz(u); }
+}
 
-        unsafe fn baz(u: MyUnion) {
-            let inner = u.foo;
-            let inner = u.bar;
-        }
-        "#,
+unsafe fn baz(u: MyUnion) {
+    let inner = u.foo;
+    let inner = u.bar;
+}
+"#,
         expect![[r#"
             57..172 '{     ...); } }': ()
             67..68 'u': MyUnion
@@ -404,19 +380,19 @@ fn infer_union() {
 fn infer_refs() {
     check_infer(
         r#"
-        fn test(a: &u32, b: &mut u32, c: *const u32, d: *mut u32) {
-            a;
-            *a;
-            &a;
-            &mut a;
-            b;
-            *b;
-            &b;
-            c;
-            *c;
-            d;
-            *d;
-        }
+fn test(a: &u32, b: &mut u32, c: *const u32, d: *mut u32) {
+    a;
+    *a;
+    &a;
+    &mut a;
+    b;
+    *b;
+    &b;
+    c;
+    *c;
+    d;
+    *d;
+}
         "#,
         expect![[r#"
             8..9 'a': &u32
@@ -450,11 +426,11 @@ fn infer_refs() {
 fn infer_raw_ref() {
     check_infer(
         r#"
-        fn test(a: i32) {
-            &raw mut a;
-            &raw const a;
-        }
-        "#,
+fn test(a: i32) {
+    &raw mut a;
+    &raw const a;
+}
+"#,
         expect![[r#"
             8..9 'a': i32
             16..53 '{     ...t a; }': ()
@@ -524,26 +500,26 @@ h";
 fn infer_unary_op() {
     check_infer(
         r#"
-        enum SomeType {}
-
-        fn test(x: SomeType) {
-            let b = false;
-            let c = !b;
-            let a = 100;
-            let d: i128 = -a;
-            let e = -100;
-            let f = !!!true;
-            let g = !42;
-            let h = !10u32;
-            let j = !a;
-            -3.14;
-            !3;
-            -x;
-            !x;
-            -"hello";
-            !"hello";
-        }
-        "#,
+enum SomeType {}
+
+fn test(x: SomeType) {
+    let b = false;
+    let c = !b;
+    let a = 100;
+    let d: i128 = -a;
+    let e = -100;
+    let f = !!!true;
+    let g = !42;
+    let h = !10u32;
+    let j = !a;
+    -3.14;
+    !3;
+    -x;
+    !x;
+    -"hello";
+    !"hello";
+}
+"#,
         expect![[r#"
             26..27 'x': SomeType
             39..271 '{     ...lo"; }': ()
@@ -594,19 +570,19 @@ fn infer_unary_op() {
 fn infer_backwards() {
     check_infer(
         r#"
-        fn takes_u32(x: u32) {}
+fn takes_u32(x: u32) {}
 
-        struct S { i32_field: i32 }
+struct S { i32_field: i32 }
 
-        fn test() -> &mut &f64 {
-            let a = unknown_function();
-            takes_u32(a);
-            let b = unknown_function();
-            S { i32_field: b };
-            let c = unknown_function();
-            &mut &c
-        }
-        "#,
+fn test() -> &mut &f64 {
+    let a = unknown_function();
+    takes_u32(a);
+    let b = unknown_function();
+    S { i32_field: b };
+    let c = unknown_function();
+    &mut &c
+}
+"#,
         expect![[r#"
             13..14 'x': u32
             21..23 '{}': ()
@@ -636,23 +612,23 @@ fn infer_backwards() {
 fn infer_self() {
     check_infer(
         r#"
-        struct S;
+struct S;
 
-        impl S {
-            fn test(&self) {
-                self;
-            }
-            fn test2(self: &Self) {
-                self;
-            }
-            fn test3() -> Self {
-                S {}
-            }
-            fn test4() -> Self {
-                Self {}
-            }
-        }
-        "#,
+impl S {
+    fn test(&self) {
+        self;
+    }
+    fn test2(self: &Self) {
+        self;
+    }
+    fn test3() -> Self {
+        S {}
+    }
+    fn test4() -> Self {
+        Self {}
+    }
+}
+"#,
         expect![[r#"
             33..37 'self': &S
             39..60 '{     ...     }': ()
@@ -672,30 +648,30 @@ fn infer_self() {
 fn infer_self_as_path() {
     check_infer(
         r#"
-        struct S1;
-        struct S2(isize);
-        enum E {
-            V1,
-            V2(u32),
-        }
+struct S1;
+struct S2(isize);
+enum E {
+    V1,
+    V2(u32),
+}
 
-        impl S1 {
-            fn test() {
-                Self;
-            }
-        }
-        impl S2 {
-            fn test() {
-                Self(1);
-            }
-        }
-        impl E {
-            fn test() {
-                Self::V1;
-                Self::V2(1);
-            }
-        }
-        "#,
+impl S1 {
+    fn test() {
+        Self;
+    }
+}
+impl S2 {
+    fn test() {
+        Self(1);
+    }
+}
+impl E {
+    fn test() {
+        Self::V1;
+        Self::V2(1);
+    }
+}
+"#,
         expect![[r#"
             86..107 '{     ...     }': ()
             96..100 'Self': S1
@@ -716,26 +692,26 @@ fn infer_self_as_path() {
 fn infer_binary_op() {
     check_infer(
         r#"
-        fn f(x: bool) -> i32 {
-            0i32
-        }
+fn f(x: bool) -> i32 {
+    0i32
+}
 
-        fn test() -> bool {
-            let x = a && b;
-            let y = true || false;
-            let z = x == y;
-            let t = x != y;
-            let minus_forty: isize = -40isize;
-            let h = minus_forty <= CONST_2;
-            let c = f(z || y) + 5;
-            let d = b;
-            let g = minus_forty ^= i;
-            let ten: usize = 10;
-            let ten_is_eleven = ten == some_num;
-
-            ten < 3
-        }
-        "#,
+fn test() -> bool {
+    let x = a && b;
+    let y = true || false;
+    let z = x == y;
+    let t = x != y;
+    let minus_forty: isize = -40isize;
+    let h = minus_forty <= CONST_2;
+    let c = f(z || y) + 5;
+    let d = b;
+    let g = minus_forty ^= i;
+    let ten: usize = 10;
+    let ten_is_eleven = ten == some_num;
+
+    ten < 3
+}
+"#,
         expect![[r#"
             5..6 'x': bool
             21..33 '{     0i32 }': i32
@@ -795,11 +771,11 @@ fn infer_binary_op() {
 fn infer_shift_op() {
     check_infer(
         r#"
-        fn test() {
-            1u32 << 5u8;
-            1u32 >> 5u8;
-        }
-        "#,
+fn test() {
+    1u32 << 5u8;
+    1u32 >> 5u8;
+}
+"#,
         expect![[r#"
             10..47 '{     ...5u8; }': ()
             16..20 '1u32': u32
@@ -816,29 +792,29 @@ fn infer_shift_op() {
 fn infer_field_autoderef() {
     check_infer(
         r#"
-        struct A {
-            b: B,
-        }
-        struct B;
-
-        fn test1(a: A) {
-            let a1 = a;
-            a1.b;
-            let a2 = &a;
-            a2.b;
-            let a3 = &mut a;
-            a3.b;
-            let a4 = &&&&&&&a;
-            a4.b;
-            let a5 = &mut &&mut &&mut a;
-            a5.b;
-        }
+struct A {
+    b: B,
+}
+struct B;
 
-        fn test2(a1: *const A, a2: *mut A) {
-            a1.b;
-            a2.b;
-        }
-        "#,
+fn test1(a: A) {
+    let a1 = a;
+    a1.b;
+    let a2 = &a;
+    a2.b;
+    let a3 = &mut a;
+    a3.b;
+    let a4 = &&&&&&&a;
+    a4.b;
+    let a5 = &mut &&mut &&mut a;
+    a5.b;
+}
+
+fn test2(a1: *const A, a2: *mut A) {
+    a1.b;
+    a2.b;
+}
+"#,
         expect![[r#"
             43..44 'a': A
             49..212 '{     ...5.b; }': ()
@@ -891,58 +867,53 @@ fn infer_field_autoderef() {
 fn infer_argument_autoderef() {
     check_infer(
         r#"
-        #[lang = "deref"]
-        pub trait Deref {
-            type Target;
-            fn deref(&self) -> &Self::Target;
-        }
+//- minicore: deref
+use core::ops::Deref;
+struct A<T>(T);
 
-        struct A<T>(T);
-
-        impl<T> A<T> {
-            fn foo(&self) -> &T {
-                &self.0
-            }
-        }
+impl<T> A<T> {
+    fn foo(&self) -> &T {
+        &self.0
+    }
+}
 
-        struct B<T>(T);
+struct B<T>(T);
 
-        impl<T> Deref for B<T> {
-            type Target = T;
-            fn deref(&self) -> &Self::Target {
-                &self.0
-            }
-        }
+impl<T> Deref for B<T> {
+    type Target = T;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
 
-        fn test() {
-            let t = A::foo(&&B(B(A(42))));
-        }
-        "#,
+fn test() {
+    let t = A::foo(&&B(B(A(42))));
+}
+"#,
         expect![[r#"
-            67..71 'self': &Self
-            138..142 'self': &A<T>
-            150..173 '{     ...     }': &T
-            160..167 '&self.0': &T
-            161..165 'self': &A<T>
-            161..167 'self.0': T
-            254..258 'self': &B<T>
-            277..300 '{     ...     }': &T
-            287..294 '&self.0': &T
-            288..292 'self': &B<T>
-            288..294 'self.0': T
-            314..352 '{     ...))); }': ()
-            324..325 't': &i32
-            328..334 'A::foo': fn foo<i32>(&A<i32>) -> &i32
-            328..349 'A::foo...42))))': &i32
-            335..348 '&&B(B(A(42)))': &&B<B<A<i32>>>
-            336..348 '&B(B(A(42)))': &B<B<A<i32>>>
-            337..338 'B': B<B<A<i32>>>(B<A<i32>>) -> B<B<A<i32>>>
-            337..348 'B(B(A(42)))': B<B<A<i32>>>
-            339..340 'B': B<A<i32>>(A<i32>) -> B<A<i32>>
-            339..347 'B(A(42))': B<A<i32>>
-            341..342 'A': A<i32>(i32) -> A<i32>
-            341..346 'A(42)': A<i32>
-            343..345 '42': i32
+            66..70 'self': &A<T>
+            78..101 '{     ...     }': &T
+            88..95 '&self.0': &T
+            89..93 'self': &A<T>
+            89..95 'self.0': T
+            182..186 'self': &B<T>
+            205..228 '{     ...     }': &T
+            215..222 '&self.0': &T
+            216..220 'self': &B<T>
+            216..222 'self.0': T
+            242..280 '{     ...))); }': ()
+            252..253 't': &i32
+            256..262 'A::foo': fn foo<i32>(&A<i32>) -> &i32
+            256..277 'A::foo...42))))': &i32
+            263..276 '&&B(B(A(42)))': &&B<B<A<i32>>>
+            264..276 '&B(B(A(42)))': &B<B<A<i32>>>
+            265..266 'B': B<B<A<i32>>>(B<A<i32>>) -> B<B<A<i32>>>
+            265..276 'B(B(A(42)))': B<B<A<i32>>>
+            267..268 'B': B<A<i32>>(A<i32>) -> B<A<i32>>
+            267..275 'B(A(42))': B<A<i32>>
+            269..270 'A': A<i32>(i32) -> A<i32>
+            269..274 'A(42)': A<i32>
+            271..273 '42': i32
         "#]],
     );
 }
@@ -951,62 +922,57 @@ fn infer_argument_autoderef() {
 fn infer_method_argument_autoderef() {
     check_infer(
         r#"
-        #[lang = "deref"]
-        pub trait Deref {
-            type Target;
-            fn deref(&self) -> &Self::Target;
-        }
+//- minicore: deref
+use core::ops::Deref;
+struct A<T>(*mut T);
 
-        struct A<T>(*mut T);
-
-        impl<T> A<T> {
-            fn foo(&self, x: &A<T>) -> &T {
-                &*x.0
-            }
-        }
+impl<T> A<T> {
+    fn foo(&self, x: &A<T>) -> &T {
+        &*x.0
+    }
+}
 
-        struct B<T>(T);
+struct B<T>(T);
 
-        impl<T> Deref for B<T> {
-            type Target = T;
-            fn deref(&self) -> &Self::Target {
-                &self.0
-            }
-        }
+impl<T> Deref for B<T> {
+    type Target = T;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
 
-        fn test(a: A<i32>) {
-            let t = A(0 as *mut _).foo(&&B(B(a)));
-        }
-        "#,
+fn test(a: A<i32>) {
+    let t = A(0 as *mut _).foo(&&B(B(a)));
+}
+"#,
         expect![[r#"
-            67..71 'self': &Self
-            143..147 'self': &A<T>
-            149..150 'x': &A<T>
-            165..186 '{     ...     }': &T
-            175..180 '&*x.0': &T
-            176..180 '*x.0': T
-            177..178 'x': &A<T>
-            177..180 'x.0': *mut T
-            267..271 'self': &B<T>
-            290..313 '{     ...     }': &T
-            300..307 '&self.0': &T
-            301..305 'self': &B<T>
-            301..307 'self.0': T
-            325..326 'a': A<i32>
-            336..382 '{     ...))); }': ()
-            346..347 't': &i32
-            350..351 'A': A<i32>(*mut i32) -> A<i32>
-            350..364 'A(0 as *mut _)': A<i32>
-            350..379 'A(0 as...B(a)))': &i32
-            352..353 '0': i32
-            352..363 '0 as *mut _': *mut i32
-            369..378 '&&B(B(a))': &&B<B<A<i32>>>
-            370..378 '&B(B(a))': &B<B<A<i32>>>
-            371..372 'B': B<B<A<i32>>>(B<A<i32>>) -> B<B<A<i32>>>
-            371..378 'B(B(a))': B<B<A<i32>>>
-            373..374 'B': B<A<i32>>(A<i32>) -> B<A<i32>>
-            373..377 'B(a)': B<A<i32>>
-            375..376 'a': A<i32>
+            71..75 'self': &A<T>
+            77..78 'x': &A<T>
+            93..114 '{     ...     }': &T
+            103..108 '&*x.0': &T
+            104..108 '*x.0': T
+            105..106 'x': &A<T>
+            105..108 'x.0': *mut T
+            195..199 'self': &B<T>
+            218..241 '{     ...     }': &T
+            228..235 '&self.0': &T
+            229..233 'self': &B<T>
+            229..235 'self.0': T
+            253..254 'a': A<i32>
+            264..310 '{     ...))); }': ()
+            274..275 't': &i32
+            278..279 'A': A<i32>(*mut i32) -> A<i32>
+            278..292 'A(0 as *mut _)': A<i32>
+            278..307 'A(0 as...B(a)))': &i32
+            280..281 '0': i32
+            280..291 '0 as *mut _': *mut i32
+            297..306 '&&B(B(a))': &&B<B<A<i32>>>
+            298..306 '&B(B(a))': &B<B<A<i32>>>
+            299..300 'B': B<B<A<i32>>>(B<A<i32>>) -> B<B<A<i32>>>
+            299..306 'B(B(a))': B<B<A<i32>>>
+            301..302 'B': B<A<i32>>(A<i32>) -> B<A<i32>>
+            301..305 'B(a)': B<A<i32>>
+            303..304 'a': A<i32>
         "#]],
     );
 }
@@ -1015,15 +981,15 @@ fn infer_method_argument_autoderef() {
 fn infer_in_elseif() {
     check_infer(
         r#"
-        struct Foo { field: i32 }
-        fn main(foo: Foo) {
-            if true {
+struct Foo { field: i32 }
+fn main(foo: Foo) {
+    if true {
 
-            } else if false {
-                foo.field
-            }
-        }
-        "#,
+    } else if false {
+        foo.field
+    }
+}
+"#,
         expect![[r#"
             34..37 'foo': Foo
             44..108 '{     ...   } }': ()
@@ -1043,28 +1009,29 @@ fn infer_in_elseif() {
 fn infer_if_match_with_return() {
     check_infer(
         r#"
-        fn foo() {
-            let _x1 = if true {
-                1
-            } else {
-                return;
-            };
-            let _x2 = if true {
-                2
-            } else {
-                return
-            };
-            let _x3 = match true {
-                true => 3,
-                _ => {
-                    return;
-                }
-            };
-            let _x4 = match true {
-                true => 4,
-                _ => return
-            };
-        }"#,
+fn foo() {
+    let _x1 = if true {
+        1
+    } else {
+        return;
+    };
+    let _x2 = if true {
+        2
+    } else {
+        return
+    };
+    let _x3 = match true {
+        true => 3,
+        _ => {
+            return;
+        }
+    };
+    let _x4 = match true {
+        true => 4,
+        _ => return
+    };
+}
+"#,
         expect![[r#"
             9..322 '{     ...  }; }': ()
             19..22 '_x1': i32
@@ -1778,7 +1745,7 @@ impl i32 { fn foo(&self) -> Foo { Foo } }
 fn main() {
     let x: i32 = i32;
     x.foo();
-        //^ Foo
+  //^^^^^^^ Foo
 }"#,
     );
 }
@@ -1796,7 +1763,7 @@ fn main() {
     fn inner() {}
     let x: i32 = i32;
     x.foo();
-        //^ Foo
+  //^^^^^^^ Foo
 }"#,
     );
 }
@@ -1814,7 +1781,7 @@ fn foo() -> &'static str { "" }
 
 fn main() {
     foo();
-      //^ &str
+  //^^^^^ &str
 }"#,
     );
 }
@@ -1832,7 +1799,7 @@ fn foo() -> &'static str { "" }
 
 fn main() {
     str::foo();
-           //^ u32
+  //^^^^^^^^^^ u32
 }"#,
     );
 }
@@ -1858,9 +1825,9 @@ mod d {
 
 fn main() {
     d::foo();
-         //^ u8
+  //^^^^^^^^ u8
     d::foo{a:0};
-           //^ u8
+  //^^^^^^^^^^^ foo
 }"#,
     );
 }
@@ -1950,6 +1917,7 @@ fn fn_pointer_return() {
 fn effects_smoke_test() {
     check_infer(
         r#"
+        //- minicore: future
         async fn main() {
             let x = unsafe { 92 };
             let y = async { async { () }.await };
@@ -1957,13 +1925,6 @@ fn effects_smoke_test() {
             let w = const { 92 };
             let t = 'a: { 92 };
         }
-
-        #[prelude_import] use future::*;
-
-        mod future {
-            #[lang = "future_trait"]
-            pub trait Future { type Output; }
-        }
         "#,
         expect![[r#"
             16..162 '{     ...2 }; }': ()
@@ -2639,11 +2600,8 @@ fn f() {
 fn infer_boxed_self_receiver() {
     check_infer(
         r#"
-#[lang = "deref"]
-pub trait Deref {
-    type Target;
-    fn deref(&self) -> &Self::Target;
-}
+//- minicore: deref
+use core::ops::Deref;
 
 struct Box<T>(T);
 
@@ -2675,40 +2633,39 @@ fn main() {
 }
         "#,
         expect![[r#"
-            67..71 'self': &Self
-            175..179 'self': &Box<T>
-            259..263 'self': &Box<Foo<T>>
-            289..291 '{}': ()
-            313..317 'self': &Box<Foo<T>>
-            346..348 '{}': ()
-            368..372 'self': Box<Foo<T>>
-            393..395 '{}': ()
-            409..630 '{     ...r(); }': ()
-            419..424 'boxed': Box<Foo<i32>>
-            427..430 'Box': Box<Foo<i32>>(Foo<i32>) -> Box<Foo<i32>>
-            427..442 'Box(Foo(0_i32))': Box<Foo<i32>>
-            431..434 'Foo': Foo<i32>(i32) -> Foo<i32>
-            431..441 'Foo(0_i32)': Foo<i32>
-            435..440 '0_i32': i32
-            453..457 'bad1': &i32
-            460..465 'boxed': Box<Foo<i32>>
-            460..477 'boxed....nner()': &i32
-            487..492 'good1': &i32
-            495..509 'Foo::get_inner': fn get_inner<i32>(&Box<Foo<i32>>) -> &i32
-            495..517 'Foo::g...boxed)': &i32
-            510..516 '&boxed': &Box<Foo<i32>>
-            511..516 'boxed': Box<Foo<i32>>
-            528..532 'bad2': &Foo<i32>
-            535..540 'boxed': Box<Foo<i32>>
-            535..551 'boxed....self()': &Foo<i32>
-            561..566 'good2': &Foo<i32>
-            569..582 'Foo::get_self': fn get_self<i32>(&Box<Foo<i32>>) -> &Foo<i32>
-            569..590 'Foo::g...boxed)': &Foo<i32>
-            583..589 '&boxed': &Box<Foo<i32>>
-            584..589 'boxed': Box<Foo<i32>>
-            601..606 'inner': Foo<i32>
-            609..614 'boxed': Box<Foo<i32>>
-            609..627 'boxed....nner()': Foo<i32>
+            104..108 'self': &Box<T>
+            188..192 'self': &Box<Foo<T>>
+            218..220 '{}': ()
+            242..246 'self': &Box<Foo<T>>
+            275..277 '{}': ()
+            297..301 'self': Box<Foo<T>>
+            322..324 '{}': ()
+            338..559 '{     ...r(); }': ()
+            348..353 'boxed': Box<Foo<i32>>
+            356..359 'Box': Box<Foo<i32>>(Foo<i32>) -> Box<Foo<i32>>
+            356..371 'Box(Foo(0_i32))': Box<Foo<i32>>
+            360..363 'Foo': Foo<i32>(i32) -> Foo<i32>
+            360..370 'Foo(0_i32)': Foo<i32>
+            364..369 '0_i32': i32
+            382..386 'bad1': &i32
+            389..394 'boxed': Box<Foo<i32>>
+            389..406 'boxed....nner()': &i32
+            416..421 'good1': &i32
+            424..438 'Foo::get_inner': fn get_inner<i32>(&Box<Foo<i32>>) -> &i32
+            424..446 'Foo::g...boxed)': &i32
+            439..445 '&boxed': &Box<Foo<i32>>
+            440..445 'boxed': Box<Foo<i32>>
+            457..461 'bad2': &Foo<i32>
+            464..469 'boxed': Box<Foo<i32>>
+            464..480 'boxed....self()': &Foo<i32>
+            490..495 'good2': &Foo<i32>
+            498..511 'Foo::get_self': fn get_self<i32>(&Box<Foo<i32>>) -> &Foo<i32>
+            498..519 'Foo::g...boxed)': &Foo<i32>
+            512..518 '&boxed': &Box<Foo<i32>>
+            513..518 'boxed': Box<Foo<i32>>
+            530..535 'inner': Foo<i32>
+            538..543 'boxed': Box<Foo<i32>>
+            538..556 'boxed....nner()': Foo<i32>
         "#]],
     );
 }
@@ -2720,7 +2677,7 @@ fn prelude_2015() {
 //- /main.rs edition:2015 crate:main deps:core
 fn f() {
     Rust;
-     //^ Rust
+  //^^^^ Rust
 }
 
 //- /core.rs crate:core
diff --git a/crates/hir_ty/src/tests/traits.rs b/crates/hir_ty/src/tests/traits.rs
index 6bcede4c4..a0ddad570 100644
--- a/crates/hir_ty/src/tests/traits.rs
+++ b/crates/hir_ty/src/tests/traits.rs
@@ -1,15 +1,16 @@
+use cov_mark::check;
 use expect_test::expect;
 
-use super::{check_infer, check_infer_with_mismatches, check_types};
+use super::{check, check_infer, check_infer_with_mismatches, check_types};
 
 #[test]
 fn infer_await() {
     check_types(
         r#"
-//- /main.rs crate:main deps:core
+//- minicore: future
 struct IntFuture;
 
-impl Future for IntFuture {
+impl core::future::Future for IntFuture {
     type Output = u64;
 }
 
@@ -18,16 +19,6 @@ fn test() {
     let v = r.await;
     v;
 } //^ u64
-
-//- /core.rs crate:core
-pub mod prelude {
-    pub mod rust_2018 {
-        #[lang = "future_trait"]
-        pub trait Future {
-            type Output;
-        }
-    }
-}
 "#,
     );
 }
@@ -36,25 +27,14 @@ pub mod prelude {
 fn infer_async() {
     check_types(
         r#"
-//- /main.rs crate:main deps:core
-async fn foo() -> u64 {
-            128
-}
+//- minicore: future
+async fn foo() -> u64 { 128 }
 
 fn test() {
     let r = foo();
     let v = r.await;
     v;
 } //^ u64
-
-//- /core.rs crate:core
-#[prelude_import] use future::*;
-mod future {
-    #[lang = "future_trait"]
-    trait Future {
-        type Output;
-    }
-}
 "#,
     );
 }
@@ -63,24 +43,13 @@ mod future {
 fn infer_desugar_async() {
     check_types(
         r#"
-//- /main.rs crate:main deps:core
-async fn foo() -> u64 {
-            128
-}
+//- minicore: future
+async fn foo() -> u64 { 128 }
 
 fn test() {
     let r = foo();
     r;
 } //^ impl Future<Output = u64>
-
-//- /core.rs crate:core
-#[prelude_import] use future::*;
-mod future {
-    trait Future {
-        type Output;
-    }
-}
-
 "#,
     );
 }
@@ -89,7 +58,7 @@ mod future {
 fn infer_async_block() {
     check_types(
         r#"
-//- /main.rs crate:main deps:core
+//- minicore: future, option
 async fn test() {
     let a = async { 42 };
     a;
@@ -101,7 +70,7 @@ async fn test() {
     b;
 //  ^ ()
     let c = async {
-        let y = Option::None;
+        let y = None;
         y
     //  ^ Option<u64>
     };
@@ -109,18 +78,6 @@ async fn test() {
     c;
 //  ^ impl Future<Output = Option<u64>>
 }
-
-enum Option<T> { None, Some(T) }
-
-//- /core.rs crate:core
-#[prelude_import] use future::*;
-mod future {
-    #[lang = "future_trait"]
-    trait Future {
-        type Output;
-    }
-}
-
 "#,
     );
 }
@@ -329,7 +286,7 @@ mod ops {
 
 #[test]
 fn infer_from_bound_1() {
-    check_infer(
+    check_types(
         r#"
 trait Trait<T> {}
 struct S<T>(T);
@@ -337,99 +294,62 @@ impl<U> Trait<U> for S<U> {}
 fn foo<T: Trait<u32>>(t: T) {}
 fn test() {
     let s = S(unknown);
+           // ^^^^^^^ u32
     foo(s);
 }"#,
-        expect![[r#"
-            85..86 't': T
-            91..93 '{}': ()
-            104..143 '{     ...(s); }': ()
-            114..115 's': S<u32>
-            118..119 'S': S<u32>(u32) -> S<u32>
-            118..128 'S(unknown)': S<u32>
-            120..127 'unknown': u32
-            134..137 'foo': fn foo<S<u32>>(S<u32>)
-            134..140 'foo(s)': ()
-            138..139 's': S<u32>
-        "#]],
     );
 }
 
 #[test]
 fn infer_from_bound_2() {
-    check_infer(
+    check_types(
         r#"
 trait Trait<T> {}
 struct S<T>(T);
 impl<U> Trait<U> for S<U> {}
-fn foo<U, T: Trait<U>>(t: T) -> U {}
+fn foo<U, T: Trait<U>>(t: T) -> U { loop {} }
 fn test() {
     let s = S(unknown);
+           // ^^^^^^^ u32
     let x: u32 = foo(s);
 }"#,
-        expect![[r#"
-            86..87 't': T
-            97..99 '{}': ()
-            110..162 '{     ...(s); }': ()
-            120..121 's': S<u32>
-            124..125 'S': S<u32>(u32) -> S<u32>
-            124..134 'S(unknown)': S<u32>
-            126..133 'unknown': u32
-            144..145 'x': u32
-            153..156 'foo': fn foo<u32, S<u32>>(S<u32>) -> u32
-            153..159 'foo(s)': u32
-            157..158 's': S<u32>
-        "#]],
     );
 }
 
 #[test]
 fn trait_default_method_self_bound_implements_trait() {
     cov_mark::check!(trait_self_implements_self);
-    check_infer(
+    check(
         r#"
 trait Trait {
     fn foo(&self) -> i64;
-    fn bar(&self) -> {
-        let x = self.foo();
+    fn bar(&self) -> () {
+        self.foo();
+     // ^^^^^^^^^^ type: i64
     }
 }"#,
-        expect![[r#"
-            26..30 'self': &Self
-            52..56 'self': &Self
-            61..96 '{     ...     }': ()
-            75..76 'x': i64
-            79..83 'self': &Self
-            79..89 'self.foo()': i64
-        "#]],
     );
 }
 
 #[test]
 fn trait_default_method_self_bound_implements_super_trait() {
-    check_infer(
+    check(
         r#"
 trait SuperTrait {
     fn foo(&self) -> i64;
 }
 trait Trait: SuperTrait {
-    fn bar(&self) -> {
-        let x = self.foo();
+    fn bar(&self) -> () {
+        self.foo();
+     // ^^^^^^^^^^ type: i64
     }
 }"#,
-        expect![[r#"
-            31..35 'self': &Self
-            85..89 'self': &Self
-            94..129 '{     ...     }': ()
-            108..109 'x': i64
-            112..116 'self': &Self
-            112..122 'self.foo()': i64
-        "#]],
     );
 }
 
 #[test]
 fn infer_project_associated_type() {
-    check_infer(
+    check_types(
         r#"
 trait Iterable {
     type Item;
@@ -438,89 +358,62 @@ struct S;
 impl Iterable for S { type Item = u32; }
 fn test<T: Iterable>() {
     let x: <S as Iterable>::Item = 1;
-    let y: <T as Iterable>::Item = no_matter;
-    let z: T::Item = no_matter;
-    let a: <T>::Item = no_matter;
+                                // ^ u32
+    let y: <T as Iterable>::Item = u;
+                                // ^ Iterable::Item<T>
+    let z: T::Item = u;
+                  // ^ Iterable::Item<T>
+    let a: <T>::Item = u;
+                    // ^ Iterable::Item<T>
 }"#,
-        expect![[r#"
-            108..261 '{     ...ter; }': ()
-            118..119 'x': u32
-            145..146 '1': u32
-            156..157 'y': Iterable::Item<T>
-            183..192 'no_matter': Iterable::Item<T>
-            202..203 'z': Iterable::Item<T>
-            215..224 'no_matter': Iterable::Item<T>
-            234..235 'a': Iterable::Item<T>
-            249..258 'no_matter': Iterable::Item<T>
-        "#]],
     );
 }
 
 #[test]
 fn infer_return_associated_type() {
-    check_infer(
+    check_types(
         r#"
 trait Iterable {
     type Item;
 }
 struct S;
 impl Iterable for S { type Item = u32; }
-fn foo1<T: Iterable>(t: T) -> T::Item {}
-fn foo2<T: Iterable>(t: T) -> <T as Iterable>::Item {}
-fn foo3<T: Iterable>(t: T) -> <T>::Item {}
+fn foo1<T: Iterable>(t: T) -> T::Item { loop {} }
+fn foo2<T: Iterable>(t: T) -> <T as Iterable>::Item { loop {} }
+fn foo3<T: Iterable>(t: T) -> <T>::Item { loop {} }
 fn test() {
-    let x = foo1(S);
-    let y = foo2(S);
-    let z = foo3(S);
+    foo1(S);
+ // ^^^^^^^ u32
+    foo2(S);
+ // ^^^^^^^ u32
+    foo3(S);
+ // ^^^^^^^ u32
 }"#,
-        expect![[r#"
-            106..107 't': T
-            123..125 '{}': ()
-            147..148 't': T
-            178..180 '{}': ()
-            202..203 't': T
-            221..223 '{}': ()
-            234..300 '{     ...(S); }': ()
-            244..245 'x': u32
-            248..252 'foo1': fn foo1<S>(S) -> <S as Iterable>::Item
-            248..255 'foo1(S)': u32
-            253..254 'S': S
-            265..266 'y': u32
-            269..273 'foo2': fn foo2<S>(S) -> <S as Iterable>::Item
-            269..276 'foo2(S)': u32
-            274..275 'S': S
-            286..287 'z': u32
-            290..294 'foo3': fn foo3<S>(S) -> <S as Iterable>::Item
-            290..297 'foo3(S)': u32
-            295..296 'S': S
-        "#]],
     );
 }
 
 #[test]
 fn infer_associated_type_bound() {
-    check_infer(
+    check_types(
         r#"
 trait Iterable {
     type Item;
 }
 fn test<T: Iterable<Item=u32>>() {
     let y: T::Item = unknown;
+                  // ^^^^^^^ u32
 }"#,
-        expect![[r#"
-            67..100 '{     ...own; }': ()
-            77..78 'y': u32
-            90..97 'unknown': u32
-        "#]],
     );
 }
 
 #[test]
 fn infer_const_body() {
+    // FIXME make check_types work with other bodies
     check_infer(
         r#"
 const A: u32 = 1 + 1;
-static B: u64 = { let x = 1; x };"#,
+static B: u64 = { let x = 1; x };
+"#,
         expect![[r#"
             15..16 '1': u32
             15..20 '1 + 1': u32
@@ -611,11 +504,11 @@ fn indexing_arrays() {
 fn infer_ops_index() {
     check_types(
         r#"
-//- /main.rs crate:main deps:std
+//- minicore: index
 struct Bar;
 struct Foo;
 
-impl std::ops::Index<u32> for Bar {
+impl core::ops::Index<u32> for Bar {
     type Output = Foo;
 }
 
@@ -624,15 +517,6 @@ fn test() {
     let b = a[1u32];
     b;
 } //^ Foo
-
-//- /std.rs crate:std
-#[prelude_import] use ops::*;
-mod ops {
-    #[lang = "index"]
-    pub trait Index<Idx> {
-        type Output;
-    }
-}
 "#,
     );
 }
@@ -641,16 +525,16 @@ mod ops {
 fn infer_ops_index_int() {
     check_types(
         r#"
-//- /main.rs crate:main deps:std
+//- minicore: index
 struct Bar;
 struct Foo;
 
-impl std::ops::Index<u32> for Bar {
+impl core::ops::Index<u32> for Bar {
     type Output = Foo;
 }
 
 struct Range;
-impl std::ops::Index<Range> for Bar {
+impl core::ops::Index<Range> for Bar {
     type Output = Bar;
 }
 
@@ -660,15 +544,6 @@ fn test() {
     b;
   //^ Foo
 }
-
-//- /std.rs crate:std
-#[prelude_import] use ops::*;
-mod ops {
-    #[lang = "index"]
-    pub trait Index<Idx> {
-        type Output;
-    }
-}
 "#,
     );
 }
@@ -677,25 +552,12 @@ mod ops {
 fn infer_ops_index_autoderef() {
     check_types(
         r#"
-//- /main.rs crate:main deps:std
+//- minicore: index, slice
 fn test() {
     let a = &[1u32, 2, 3];
-    let b = a[1u32];
+    let b = a[1];
     b;
 } //^ u32
-
-//- /std.rs crate:std
-impl<T> ops::Index<u32> for [T] {
-    type Output = T;
-}
-
-#[prelude_import] use ops::*;
-mod ops {
-    #[lang = "index"]
-    pub trait Index<Idx> {
-        type Output;
-    }
-}
 "#,
     );
 }
@@ -704,25 +566,20 @@ mod ops {
 fn deref_trait() {
     check_types(
         r#"
-#[lang = "deref"]
-trait Deref {
-    type Target;
-    fn deref(&self) -> &Self::Target;
-}
-
+//- minicore: deref
 struct Arc<T>;
-impl<T> Deref for Arc<T> {
+impl<T> core::ops::Deref for Arc<T> {
     type Target = T;
 }
 
 struct S;
 impl S {
-    fn foo(&self) -> u128 {}
+    fn foo(&self) -> u128 { 0 }
 }
 
 fn test(s: Arc<S>) {
     (*s, s.foo());
-} //^ (S, u128)
+} //^^^^^^^^^^^^^ (S, u128)
 "#,
     );
 }
@@ -731,16 +588,10 @@ fn test(s: Arc<S>) {
 fn deref_trait_with_inference_var() {
     check_types(
         r#"
-//- /main.rs
-#[lang = "deref"]
-trait Deref {
-    type Target;
-    fn deref(&self) -> &Self::Target;
-}
-
+//- minicore: deref
 struct Arc<T>;
-fn new_arc<T>() -> Arc<T> {}
-impl<T> Deref for Arc<T> {
+fn new_arc<T>() -> Arc<T> { Arc }
+impl<T> core::ops::Deref for Arc<T> {
     type Target = T;
 }
 
@@ -749,8 +600,8 @@ fn foo(a: Arc<S>) {}
 
 fn test() {
     let a = new_arc();
-    let b = (*a);
-          //^ S
+    let b = *a;
+          //^^ S
     foo(a);
 }
 "#,
@@ -761,21 +612,16 @@ fn test() {
 fn deref_trait_infinite_recursion() {
     check_types(
         r#"
-#[lang = "deref"]
-trait Deref {
-    type Target;
-    fn deref(&self) -> &Self::Target;
-}
-
+//- minicore: deref
 struct S;
 
-impl Deref for S {
+impl core::ops::Deref for S {
     type Target = S;
 }
 
 fn test(s: S) {
     s.foo();
-}       //^ {unknown}
+} //^^^^^^^ {unknown}
 "#,
     );
 }
@@ -784,25 +630,20 @@ fn test(s: S) {
 fn deref_trait_with_question_mark_size() {
     check_types(
         r#"
-#[lang = "deref"]
-trait Deref {
-    type Target;
-    fn deref(&self) -> &Self::Target;
-}
-
+//- minicore: deref
 struct Arc<T>;
-impl<T> Deref for Arc<T> {
+impl<T: ?Sized> core::ops::Deref for Arc<T> {
     type Target = T;
 }
 
 struct S;
 impl S {
-    fn foo(&self) -> u128 {}
+    fn foo(&self) -> u128 { 0 }
 }
 
 fn test(s: Arc<S>) {
     (*s, s.foo());
-} //^ (S, u128)
+} //^^^^^^^^^^^^^ (S, u128)
 "#,
     );
 }
@@ -816,11 +657,11 @@ struct S;
 trait Trait<T> {}
 impl Trait<u32> for S {}
 
-fn foo<T: Trait<U>, U>(t: T) -> U {}
+fn foo<T: Trait<U>, U>(t: T) -> U { loop {} }
 
 fn test(s: S) {
-    (foo(s));
-} //^ u32
+    foo(s);
+} //^^^^^^ u32
 "#,
     );
 }
@@ -837,12 +678,12 @@ impl Trait<isize> for S {}
 
 struct O;
 impl O {
-    fn foo<T: Trait<U>, U>(&self, t: T) -> U {}
+    fn foo<T: Trait<U>, U>(&self, t: T) -> U { loop {} }
 }
 
 fn test() {
     O.foo(S);
-}      //^ isize
+} //^^^^^^^^ isize
 "#,
     );
 }
@@ -857,12 +698,12 @@ trait Trait<T> {}
 impl Trait<i64> for S {}
 
 impl S {
-    fn foo<U>(&self) -> U where Self: Trait<U> {}
+    fn foo<U>(&self) -> U where Self: Trait<U> { loop {} }
 }
 
 fn test() {
     S.foo();
-}       //^ i64
+} //^^^^^^^ i64
 "#,
     );
 }
@@ -878,12 +719,12 @@ impl Trait<&str> for S {}
 
 struct O<T>;
 impl<U, T: Trait<U>> O<T> {
-    fn foo(&self) -> U {}
+    fn foo(&self) -> U { loop {} }
 }
 
 fn test(o: O<S>) {
     o.foo();
-}       //^ &str
+} //^^^^^^^ &str
 "#,
     );
 }
@@ -898,7 +739,7 @@ struct S;
 impl Clone for S {}
 impl<T> Trait for T where T: Clone {}
 fn test<T: Clone>(t: T) { t.foo(); }
-                             //^ u128
+                        //^^^^^^^ u128
 "#,
     );
 }
@@ -914,7 +755,7 @@ struct S;
 impl Clone for S {}
 impl<T> Trait for T where T: Clone {}
 fn test<T>(t: T) { t.foo(); }
-                       //^ {unknown}
+                 //^^^^^^^ {unknown}
 "#,
     );
 }
@@ -927,7 +768,7 @@ trait Trait { fn foo(self) -> u128; }
 struct S;
 impl Trait for S {}
 fn test<T: Trait>(t: T) { t.foo(); }
-                              //^ u128
+                        //^^^^^^^ u128
 "#,
     );
 }
@@ -940,7 +781,7 @@ trait Trait { fn foo(self) -> u128; }
 struct S;
 impl Trait for S {}
 fn test<T>(t: T) { t.foo(); }
-                       //^ {unknown}
+                 //^^^^^^^ {unknown}
 "#,
     );
 }
@@ -949,16 +790,13 @@ fn test<T>(t: T) { t.foo(); }
 fn generic_param_env_deref() {
     check_types(
         r#"
-#[lang = "deref"]
-trait Deref {
-    type Target;
-}
+//- minicore: deref
 trait Trait {}
-impl<T> Deref for T where T: Trait {
+impl<T> core::ops::Deref for T where T: Trait {
     type Target = i128;
 }
-fn test<T: Trait>(t: T) { (*t); }
-                        //^ i128
+fn test<T: Trait>(t: T) { *t; }
+                        //^^ i128
 "#,
     );
 }
@@ -1475,17 +1313,16 @@ fn test(
 }
 
 #[test]
-#[ignore]
 fn error_bound_chalk() {
     check_types(
         r#"
 trait Trait {
-    fn foo(&self) -> u32 {}
+    fn foo(&self) -> u32 { 0 }
 }
 
 fn test(x: (impl Trait + UnknownTrait)) {
     x.foo();
-}       //^ u32
+} //^^^^^^^ u32
 "#,
     );
 }
@@ -1558,7 +1395,7 @@ fn test<T: Trait<Type = u32>>(x: T, y: impl Trait<Type = i64>) {
 fn impl_trait_assoc_binding_projection_bug() {
     check_types(
         r#"
-//- /main.rs crate:main deps:std
+//- minicore: iterator
 pub trait Language {
     type Kind;
 }
@@ -1576,21 +1413,7 @@ trait Clone {
 fn api_walkthrough() {
     for node in foo() {
         node.clone();
-    }            //^ {unknown}
-}
-
-//- /std.rs crate:std
-#[prelude_import] use iter::*;
-mod iter {
-    trait IntoIterator {
-        type Item;
-    }
-    trait Iterator {
-        type Item;
-    }
-    impl<T: Iterator> IntoIterator for T {
-        type Item = <T as Iterator>::Item;
-    }
+    } //^^^^^^^^^^^^ {unknown}
 }
 "#,
     );
@@ -1627,13 +1450,13 @@ fn where_clause_trait_in_scope_for_method_resolution() {
         r#"
 mod foo {
     trait Trait {
-        fn foo(&self) -> u32 {}
+        fn foo(&self) -> u32 { 0 }
     }
 }
 
 fn test<T: foo::Trait>(x: T) {
     x.foo();
-}      //^ u32
+} //^^^^^^^ u32
 "#,
     );
 }
@@ -1838,20 +1661,7 @@ fn test() {
 fn fn_trait_deref_with_ty_default() {
     check_infer(
         r#"
-#[lang = "deref"]
-trait Deref {
-    type Target;
-
-    fn deref(&self) -> &Self::Target;
-}
-
-#[lang="fn_once"]
-trait FnOnce<Args> {
-    type Output;
-
-    fn call_once(self, args: Args) -> Self::Output;
-}
-
+//- minicore: deref, fn
 struct Foo;
 
 impl Foo {
@@ -1864,7 +1674,7 @@ impl<T, F> Lazy<T, F> {
     pub fn new(f: F) -> Lazy<T, F> {}
 }
 
-impl<T, F: FnOnce() -> T> Deref for Lazy<T, F> {
+impl<T, F: FnOnce() -> T> core::ops::Deref for Lazy<T, F> {
     type Target = T;
 }
 
@@ -1878,32 +1688,29 @@ fn test() {
     let r2 = lazy2.foo();
 }"#,
         expect![[r#"
-            64..68 'self': &Self
-            165..169 'self': Self
-            171..175 'args': Args
-            239..243 'self': &Foo
-            254..256 '{}': ()
-            334..335 'f': F
-            354..356 '{}': ()
-            443..689 '{     ...o(); }': ()
-            453..458 'lazy1': Lazy<Foo, || -> Foo>
-            475..484 'Lazy::new': fn new<Foo, || -> Foo>(|| -> Foo) -> Lazy<Foo, || -> Foo>
-            475..492 'Lazy::...| Foo)': Lazy<Foo, || -> Foo>
-            485..491 '|| Foo': || -> Foo
-            488..491 'Foo': Foo
-            502..504 'r1': usize
-            507..512 'lazy1': Lazy<Foo, || -> Foo>
-            507..518 'lazy1.foo()': usize
-            560..575 'make_foo_fn_ptr': fn() -> Foo
-            591..602 'make_foo_fn': fn make_foo_fn() -> Foo
-            612..617 'lazy2': Lazy<Foo, fn() -> Foo>
-            634..643 'Lazy::new': fn new<Foo, fn() -> Foo>(fn() -> Foo) -> Lazy<Foo, fn() -> Foo>
-            634..660 'Lazy::...n_ptr)': Lazy<Foo, fn() -> Foo>
-            644..659 'make_foo_fn_ptr': fn() -> Foo
-            670..672 'r2': usize
-            675..680 'lazy2': Lazy<Foo, fn() -> Foo>
-            675..686 'lazy2.foo()': usize
-            549..551 '{}': ()
+            36..40 'self': &Foo
+            51..53 '{}': ()
+            131..132 'f': F
+            151..153 '{}': ()
+            251..497 '{     ...o(); }': ()
+            261..266 'lazy1': Lazy<Foo, || -> Foo>
+            283..292 'Lazy::new': fn new<Foo, || -> Foo>(|| -> Foo) -> Lazy<Foo, || -> Foo>
+            283..300 'Lazy::...| Foo)': Lazy<Foo, || -> Foo>
+            293..299 '|| Foo': || -> Foo
+            296..299 'Foo': Foo
+            310..312 'r1': usize
+            315..320 'lazy1': Lazy<Foo, || -> Foo>
+            315..326 'lazy1.foo()': usize
+            368..383 'make_foo_fn_ptr': fn() -> Foo
+            399..410 'make_foo_fn': fn make_foo_fn() -> Foo
+            420..425 'lazy2': Lazy<Foo, fn() -> Foo>
+            442..451 'Lazy::new': fn new<Foo, fn() -> Foo>(fn() -> Foo) -> Lazy<Foo, fn() -> Foo>
+            442..468 'Lazy::...n_ptr)': Lazy<Foo, fn() -> Foo>
+            452..467 'make_foo_fn_ptr': fn() -> Foo
+            478..480 'r2': usize
+            483..488 'lazy2': Lazy<Foo, fn() -> Foo>
+            483..494 'lazy2.foo()': usize
+            357..359 '{}': ()
         "#]],
     );
 }
@@ -1912,11 +1719,7 @@ fn test() {
 fn closure_1() {
     check_infer_with_mismatches(
         r#"
-#[lang = "fn_once"]
-trait FnOnce<Args> {
-    type Output;
-}
-
+//- minicore: fn
 enum Option<T> { Some(T), None }
 impl<T> Option<T> {
     fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Option<U> { loop {} }
@@ -1929,34 +1732,34 @@ fn test() {
     let y: Option<i64> = x.map(|_v| 1);
 }"#,
         expect![[r#"
-            147..151 'self': Option<T>
-            153..154 'f': F
-            172..183 '{ loop {} }': Option<U>
-            174..181 'loop {}': !
-            179..181 '{}': ()
-            197..316 '{     ... 1); }': ()
-            207..208 'x': Option<u32>
-            211..223 'Option::Some': Some<u32>(u32) -> Option<u32>
-            211..229 'Option...(1u32)': Option<u32>
-            224..228 '1u32': u32
-            235..236 'x': Option<u32>
-            235..251 'x.map(...v + 1)': Option<u32>
-            241..250 '|v| v + 1': |u32| -> u32
-            242..243 'v': u32
-            245..246 'v': u32
-            245..250 'v + 1': u32
-            249..250 '1': u32
-            257..258 'x': Option<u32>
-            257..273 'x.map(... 1u64)': Option<u64>
-            263..272 '|_v| 1u64': |u32| -> u64
-            264..266 '_v': u32
-            268..272 '1u64': u64
-            283..284 'y': Option<i64>
-            300..301 'x': Option<u32>
-            300..313 'x.map(|_v| 1)': Option<i64>
-            306..312 '|_v| 1': |u32| -> i64
-            307..309 '_v': u32
-            311..312 '1': i64
+            86..90 'self': Option<T>
+            92..93 'f': F
+            111..122 '{ loop {} }': Option<U>
+            113..120 'loop {}': !
+            118..120 '{}': ()
+            136..255 '{     ... 1); }': ()
+            146..147 'x': Option<u32>
+            150..162 'Option::Some': Some<u32>(u32) -> Option<u32>
+            150..168 'Option...(1u32)': Option<u32>
+            163..167 '1u32': u32
+            174..175 'x': Option<u32>
+            174..190 'x.map(...v + 1)': Option<u32>
+            180..189 '|v| v + 1': |u32| -> u32
+            181..182 'v': u32
+            184..185 'v': u32
+            184..189 'v + 1': u32
+            188..189 '1': u32
+            196..197 'x': Option<u32>
+            196..212 'x.map(... 1u64)': Option<u64>
+            202..211 '|_v| 1u64': |u32| -> u64
+            203..205 '_v': u32
+            207..211 '1u64': u64
+            222..223 'y': Option<i64>
+            239..240 'x': Option<u32>
+            239..252 'x.map(|_v| 1)': Option<i64>
+            245..251 '|_v| 1': |u32| -> i64
+            246..248 '_v': u32
+            250..251 '1': i64
         "#]],
     );
 }
@@ -2030,11 +1833,7 @@ fn test<F: FnOnce(u32) -> u64>(f: F) {
 fn closure_as_argument_inference_order() {
     check_infer_with_mismatches(
         r#"
-#[lang = "fn_once"]
-trait FnOnce<Args> {
-    type Output;
-}
-
+//- minicore: fn
 fn foo1<T, U, F: FnOnce(T) -> U>(x: T, f: F) -> U { loop {} }
 fn foo2<T, U, F: FnOnce(T) -> U>(f: F, x: T) -> U { loop {} }
 
@@ -2053,62 +1852,62 @@ fn test() {
     let x4 = S.foo2(|s| s.method(), S);
 }"#,
         expect![[r#"
-            94..95 'x': T
-            100..101 'f': F
-            111..122 '{ loop {} }': U
-            113..120 'loop {}': !
-            118..120 '{}': ()
-            156..157 'f': F
-            162..163 'x': T
-            173..184 '{ loop {} }': U
-            175..182 'loop {}': !
-            180..182 '{}': ()
-            219..223 'self': S
-            271..275 'self': S
-            277..278 'x': T
-            283..284 'f': F
-            294..305 '{ loop {} }': U
-            296..303 'loop {}': !
-            301..303 '{}': ()
-            343..347 'self': S
-            349..350 'f': F
-            355..356 'x': T
-            366..377 '{ loop {} }': U
-            368..375 'loop {}': !
-            373..375 '{}': ()
-            391..550 '{     ... S); }': ()
-            401..403 'x1': u64
-            406..410 'foo1': fn foo1<S, u64, |S| -> u64>(S, |S| -> u64) -> u64
-            406..429 'foo1(S...hod())': u64
-            411..412 'S': S
-            414..428 '|s| s.method()': |S| -> u64
-            415..416 's': S
-            418..419 's': S
-            418..428 's.method()': u64
-            439..441 'x2': u64
-            444..448 'foo2': fn foo2<S, u64, |S| -> u64>(|S| -> u64, S) -> u64
-            444..467 'foo2(|...(), S)': u64
-            449..463 '|s| s.method()': |S| -> u64
-            450..451 's': S
-            453..454 's': S
-            453..463 's.method()': u64
-            465..466 'S': S
-            477..479 'x3': u64
-            482..483 'S': S
-            482..507 'S.foo1...hod())': u64
-            489..490 'S': S
-            492..506 '|s| s.method()': |S| -> u64
-            493..494 's': S
-            496..497 's': S
-            496..506 's.method()': u64
-            517..519 'x4': u64
-            522..523 'S': S
-            522..547 'S.foo2...(), S)': u64
-            529..543 '|s| s.method()': |S| -> u64
-            530..531 's': S
-            533..534 's': S
-            533..543 's.method()': u64
-            545..546 'S': S
+            33..34 'x': T
+            39..40 'f': F
+            50..61 '{ loop {} }': U
+            52..59 'loop {}': !
+            57..59 '{}': ()
+            95..96 'f': F
+            101..102 'x': T
+            112..123 '{ loop {} }': U
+            114..121 'loop {}': !
+            119..121 '{}': ()
+            158..162 'self': S
+            210..214 'self': S
+            216..217 'x': T
+            222..223 'f': F
+            233..244 '{ loop {} }': U
+            235..242 'loop {}': !
+            240..242 '{}': ()
+            282..286 'self': S
+            288..289 'f': F
+            294..295 'x': T
+            305..316 '{ loop {} }': U
+            307..314 'loop {}': !
+            312..314 '{}': ()
+            330..489 '{     ... S); }': ()
+            340..342 'x1': u64
+            345..349 'foo1': fn foo1<S, u64, |S| -> u64>(S, |S| -> u64) -> u64
+            345..368 'foo1(S...hod())': u64
+            350..351 'S': S
+            353..367 '|s| s.method()': |S| -> u64
+            354..355 's': S
+            357..358 's': S
+            357..367 's.method()': u64
+            378..380 'x2': u64
+            383..387 'foo2': fn foo2<S, u64, |S| -> u64>(|S| -> u64, S) -> u64
+            383..406 'foo2(|...(), S)': u64
+            388..402 '|s| s.method()': |S| -> u64
+            389..390 's': S
+            392..393 's': S
+            392..402 's.method()': u64
+            404..405 'S': S
+            416..418 'x3': u64
+            421..422 'S': S
+            421..446 'S.foo1...hod())': u64
+            428..429 'S': S
+            431..445 '|s| s.method()': |S| -> u64
+            432..433 's': S
+            435..436 's': S
+            435..445 's.method()': u64
+            456..458 'x4': u64
+            461..462 'S': S
+            461..486 'S.foo2...(), S)': u64
+            468..482 '|s| s.method()': |S| -> u64
+            469..470 's': S
+            472..473 's': S
+            472..482 's.method()': u64
+            484..485 'S': S
         "#]],
     );
 }
@@ -2117,14 +1916,10 @@ fn test() {
 fn fn_item_fn_trait() {
     check_types(
         r#"
-#[lang = "fn_once"]
-trait FnOnce<Args> {
-    type Output;
-}
-
+//- minicore: fn
 struct S;
 
-fn foo() -> S {}
+fn foo() -> S { S }
 
 fn takes_closure<U, F: FnOnce() -> U>(f: F) -> U { f() }
 
@@ -2151,7 +1946,7 @@ trait Trait2 {
 fn test<T: Trait>() where T::Item: Trait2 {
     let x: T::Item = no_matter;
     x.foo();
-}       //^ u32
+} //^^^^^^^ u32
 "#,
     );
 }
@@ -2171,7 +1966,7 @@ trait Trait2 {
 fn test<T, U>() where T::Item: Trait2, T: Trait<U::Item>, U: Trait<()> {
     let x: T::Item = no_matter;
     x.foo();
-}       //^ u32
+} //^^^^^^^ u32
 "#,
     );
 }
@@ -2234,7 +2029,7 @@ impl Trait for S {
 
 fn test() {
     S.f();
-}     //^ u32
+} //^^^^^ u32
 "#,
     );
 }
@@ -2262,7 +2057,7 @@ where
 
 fn foo<I: Interner>(interner: &I, t: Ty<I>) {
     fold(interner, t);
-}     //^ Ty<I>
+} //^^^^^^^^^^^^^^^^^ Ty<I>
 "#,
     );
 }
@@ -2281,7 +2076,7 @@ impl Trait<Self> for S {}
 
 fn test() {
     S.foo();
-}       //^ ()
+} //^^^^^^^ ()
 "#,
     );
 }
@@ -2300,7 +2095,7 @@ impl Trait for S<Self> {}
 
 fn test() {
     S.foo();
-}       //^ {unknown}
+} //^^^^^^^ {unknown}
 "#,
     );
 }
@@ -2318,7 +2113,7 @@ trait Trait2<T> {}
 
 fn test<T: Trait>() where T: Trait2<T::Item> {
     let x: T::Item = no_matter;
-}                       //^ {unknown}
+}                  //^^^^^^^^^ {unknown}
 "#,
     );
 }
@@ -2335,7 +2130,7 @@ trait Trait<T> {
 
 fn test<T, U>() where T: Trait<U::Item>, U: Trait<T::Item> {
     let x: T::Item = no_matter;
-}                   //^ {unknown}
+}                  //^^^^^^^^^ {unknown}
 "#,
     );
 }
@@ -2353,7 +2148,7 @@ trait Trait {
 
 fn test<T>() where T: Trait<OtherItem = T::Item> {
     let x: T::Item = no_matter;
-}                   //^ Trait::Item<T>
+}                  //^^^^^^^^^ Trait::Item<T>
 "#,
     );
 }
@@ -2385,7 +2180,7 @@ fn test<T>(t: T) where T: UnificationStoreMut {
     t.push(x);
     let y: Key<T>;
     (x, y);
-}      //^ (UnificationStoreBase::Key<T>, UnificationStoreBase::Key<T>)
+} //^^^^^^ (UnificationStoreBase::Key<T>, UnificationStoreBase::Key<T>)
 "#,
     );
 }
@@ -2410,7 +2205,7 @@ impl<T: Iterator> Iterator for S<T> {
 fn test<I: Iterator<Item: OtherTrait<u32>>>() {
     let x: <S<I> as Iterator>::Item;
     x.foo();
-}       //^ u32
+} //^^^^^^^ u32
 "#,
     );
 }
@@ -2560,12 +2355,7 @@ fn test() -> impl Trait<i32> {
 fn assoc_types_from_bounds() {
     check_infer(
         r#"
-//- /main.rs
-#[lang = "fn_once"]
-trait FnOnce<Args> {
-    type Output;
-}
-
+//- minicore: fn
 trait T {
     type O;
 }
@@ -2584,15 +2374,15 @@ fn main() {
     f::<(), _>(|z| { z; });
 }"#,
         expect![[r#"
-            133..135 '_v': F
-            178..181 '{ }': ()
-            193..224 '{     ... }); }': ()
-            199..209 'f::<(), _>': fn f<(), |&()| -> ()>(|&()| -> ())
-            199..221 'f::<()... z; })': ()
-            210..220 '|z| { z; }': |&()| -> ()
-            211..212 'z': &()
-            214..220 '{ z; }': ()
-            216..217 'z': &()
+            72..74 '_v': F
+            117..120 '{ }': ()
+            132..163 '{     ... }); }': ()
+            138..148 'f::<(), _>': fn f<(), |&()| -> ()>(|&()| -> ())
+            138..160 'f::<()... z; })': ()
+            149..159 '|z| { z; }': |&()| -> ()
+            150..151 'z': &()
+            153..159 '{ z; }': ()
+            155..156 'z': &()
         "#]],
     );
 }
@@ -2617,7 +2407,7 @@ impl<T: Trait> Trait for S<T> {
 fn test<T: Trait>() {
     let y: <S<T> as Trait>::Item = no_matter;
     y.foo();
-}       //^ u32
+} //^^^^^^^ u32
 "#,
     );
 }
@@ -2626,12 +2416,9 @@ fn test<T: Trait>() {
 fn dyn_trait_through_chalk() {
     check_types(
         r#"
+//- minicore: deref
 struct Box<T> {}
-#[lang = "deref"]
-trait Deref {
-    type Target;
-}
-impl<T> Deref for Box<T> {
+impl<T> core::ops::Deref for Box<T> {
     type Target = T;
 }
 trait Trait {
@@ -2640,7 +2427,7 @@ trait Trait {
 
 fn test(x: Box<dyn Trait>) {
     x.foo();
-}       //^ ()
+} //^^^^^^^ ()
 "#,
     );
 }
@@ -2659,7 +2446,7 @@ impl ToOwned for str {
 }
 fn test() {
     "foo".to_owned();
-}               //^ String
+} //^^^^^^^^^^^^^^^^ String
 "#,
     );
 }
@@ -2668,17 +2455,7 @@ fn test() {
 fn iterator_chain() {
     check_infer_with_mismatches(
         r#"
-//- /main.rs
-#[lang = "fn_once"]
-trait FnOnce<Args> {
-    type Output;
-}
-#[lang = "fn_mut"]
-trait FnMut<Args>: FnOnce<Args> { }
-
-enum Option<T> { Some(T), None }
-use Option::*;
-
+//- minicore: fn, option
 pub trait Iterator {
     type Item;
 
@@ -2738,46 +2515,46 @@ fn main() {
     .for_each(|y| { y; });
 }"#,
         expect![[r#"
-            226..230 'self': Self
-            232..233 'f': F
-            317..328 '{ loop {} }': FilterMap<Self, F>
-            319..326 'loop {}': !
-            324..326 '{}': ()
-            349..353 'self': Self
-            355..356 'f': F
-            405..416 '{ loop {} }': ()
-            407..414 'loop {}': !
-            412..414 '{}': ()
-            525..529 'self': Self
-            854..858 'self': I
-            865..885 '{     ...     }': I
-            875..879 'self': I
-            944..955 '{ loop {} }': Vec<T>
-            946..953 'loop {}': !
-            951..953 '{}': ()
-            1142..1269 '{     ... }); }': ()
-            1148..1163 'Vec::<i32>::new': fn new<i32>() -> Vec<i32>
-            1148..1165 'Vec::<...:new()': Vec<i32>
-            1148..1177 'Vec::<...iter()': IntoIter<i32>
-            1148..1240 'Vec::<...one })': FilterMap<IntoIter<i32>, |i32| -> Option<u32>>
-            1148..1266 'Vec::<... y; })': ()
-            1194..1239 '|x| if...None }': |i32| -> Option<u32>
-            1195..1196 'x': i32
-            1198..1239 'if x >...None }': Option<u32>
-            1201..1202 'x': i32
-            1201..1206 'x > 0': bool
-            1205..1206 '0': i32
-            1207..1225 '{ Some...u32) }': Option<u32>
-            1209..1213 'Some': Some<u32>(u32) -> Option<u32>
-            1209..1223 'Some(x as u32)': Option<u32>
-            1214..1215 'x': i32
-            1214..1222 'x as u32': u32
-            1231..1239 '{ None }': Option<u32>
-            1233..1237 'None': Option<u32>
-            1255..1265 '|y| { y; }': |u32| -> ()
-            1256..1257 'y': u32
-            1259..1265 '{ y; }': ()
-            1261..1262 'y': u32
+            61..65 'self': Self
+            67..68 'f': F
+            152..163 '{ loop {} }': FilterMap<Self, F>
+            154..161 'loop {}': !
+            159..161 '{}': ()
+            184..188 'self': Self
+            190..191 'f': F
+            240..251 '{ loop {} }': ()
+            242..249 'loop {}': !
+            247..249 '{}': ()
+            360..364 'self': Self
+            689..693 'self': I
+            700..720 '{     ...     }': I
+            710..714 'self': I
+            779..790 '{ loop {} }': Vec<T>
+            781..788 'loop {}': !
+            786..788 '{}': ()
+            977..1104 '{     ... }); }': ()
+            983..998 'Vec::<i32>::new': fn new<i32>() -> Vec<i32>
+            983..1000 'Vec::<...:new()': Vec<i32>
+            983..1012 'Vec::<...iter()': IntoIter<i32>
+            983..1075 'Vec::<...one })': FilterMap<IntoIter<i32>, |i32| -> Option<u32>>
+            983..1101 'Vec::<... y; })': ()
+            1029..1074 '|x| if...None }': |i32| -> Option<u32>
+            1030..1031 'x': i32
+            1033..1074 'if x >...None }': Option<u32>
+            1036..1037 'x': i32
+            1036..1041 'x > 0': bool
+            1040..1041 '0': i32
+            1042..1060 '{ Some...u32) }': Option<u32>
+            1044..1048 'Some': Some<u32>(u32) -> Option<u32>
+            1044..1058 'Some(x as u32)': Option<u32>
+            1049..1050 'x': i32
+            1049..1057 'x as u32': u32
+            1066..1074 '{ None }': Option<u32>
+            1068..1072 'None': Option<u32>
+            1090..1100 '|y| { y; }': |u32| -> ()
+            1091..1092 'y': u32
+            1094..1100 '{ y; }': ()
+            1096..1097 'y': u32
         "#]],
     );
 }
@@ -2809,7 +2586,7 @@ impl<T:A> B for T {
 
 fn main() {
     Bar::foo();
-}          //^ Foo
+} //^^^^^^^^^^ Foo
 "#,
     );
 }
@@ -2841,9 +2618,7 @@ fn test(x: &dyn Foo) {
 fn builtin_copy() {
     check_infer_with_mismatches(
         r#"
-#[lang = "copy"]
-trait Copy {}
-
+//- minicore: copy
 struct IsCopy;
 impl Copy for IsCopy {}
 struct NotCopy;
@@ -2858,20 +2633,20 @@ fn test() {
     (IsCopy, NotCopy).test();
 }"#,
         expect![[r#"
-            110..114 'self': &Self
-            166..267 '{     ...t(); }': ()
-            172..178 'IsCopy': IsCopy
-            172..185 'IsCopy.test()': bool
-            191..198 'NotCopy': NotCopy
-            191..205 'NotCopy.test()': {unknown}
-            211..227 '(IsCop...sCopy)': (IsCopy, IsCopy)
-            211..234 '(IsCop...test()': bool
-            212..218 'IsCopy': IsCopy
-            220..226 'IsCopy': IsCopy
-            240..257 '(IsCop...tCopy)': (IsCopy, NotCopy)
-            240..264 '(IsCop...test()': {unknown}
-            241..247 'IsCopy': IsCopy
-            249..256 'NotCopy': NotCopy
+            78..82 'self': &Self
+            134..235 '{     ...t(); }': ()
+            140..146 'IsCopy': IsCopy
+            140..153 'IsCopy.test()': bool
+            159..166 'NotCopy': NotCopy
+            159..173 'NotCopy.test()': {unknown}
+            179..195 '(IsCop...sCopy)': (IsCopy, IsCopy)
+            179..202 '(IsCop...test()': bool
+            180..186 'IsCopy': IsCopy
+            188..194 'IsCopy': IsCopy
+            208..225 '(IsCop...tCopy)': (IsCopy, NotCopy)
+            208..232 '(IsCop...test()': {unknown}
+            209..215 'IsCopy': IsCopy
+            217..224 'NotCopy': NotCopy
         "#]],
     );
 }
@@ -2880,9 +2655,7 @@ fn test() {
 fn builtin_fn_def_copy() {
     check_infer_with_mismatches(
         r#"
-#[lang = "copy"]
-trait Copy {}
-
+//- minicore: copy
 fn foo() {}
 fn bar<T: Copy>(T) -> T {}
 struct Struct(usize);
@@ -2898,20 +2671,20 @@ fn test() {
     Enum::Variant.test();
 }"#,
         expect![[r#"
-            41..43 '{}': ()
-            60..61 'T': {unknown}
-            68..70 '{}': ()
-            68..70: expected T, got ()
-            145..149 'self': &Self
-            201..281 '{     ...t(); }': ()
-            207..210 'foo': fn foo()
-            207..217 'foo.test()': bool
-            223..226 'bar': fn bar<{unknown}>({unknown}) -> {unknown}
-            223..233 'bar.test()': bool
-            239..245 'Struct': Struct(usize) -> Struct
-            239..252 'Struct.test()': bool
-            258..271 'Enum::Variant': Variant(usize) -> Enum
-            258..278 'Enum::...test()': bool
+            9..11 '{}': ()
+            28..29 'T': {unknown}
+            36..38 '{}': ()
+            36..38: expected T, got ()
+            113..117 'self': &Self
+            169..249 '{     ...t(); }': ()
+            175..178 'foo': fn foo()
+            175..185 'foo.test()': bool
+            191..194 'bar': fn bar<{unknown}>({unknown}) -> {unknown}
+            191..201 'bar.test()': bool
+            207..213 'Struct': Struct(usize) -> Struct
+            207..220 'Struct.test()': bool
+            226..239 'Enum::Variant': Variant(usize) -> Enum
+            226..246 'Enum::...test()': bool
         "#]],
     );
 }
@@ -2920,9 +2693,7 @@ fn test() {
 fn builtin_fn_ptr_copy() {
     check_infer_with_mismatches(
         r#"
-#[lang = "copy"]
-trait Copy {}
-
+//- minicore: copy
 trait Test { fn test(&self) -> bool; }
 impl<T: Copy> Test for T {}
 
@@ -2932,17 +2703,17 @@ fn test(f1: fn(), f2: fn(usize) -> u8, f3: fn(u8, u8) -> &u8) {
     f3.test();
 }"#,
         expect![[r#"
-            54..58 'self': &Self
-            108..110 'f1': fn()
-            118..120 'f2': fn(usize) -> u8
-            139..141 'f3': fn(u8, u8) -> &u8
-            162..210 '{     ...t(); }': ()
-            168..170 'f1': fn()
-            168..177 'f1.test()': bool
-            183..185 'f2': fn(usize) -> u8
-            183..192 'f2.test()': bool
-            198..200 'f3': fn(u8, u8) -> &u8
-            198..207 'f3.test()': bool
+            22..26 'self': &Self
+            76..78 'f1': fn()
+            86..88 'f2': fn(usize) -> u8
+            107..109 'f3': fn(u8, u8) -> &u8
+            130..178 '{     ...t(); }': ()
+            136..138 'f1': fn()
+            136..145 'f1.test()': bool
+            151..153 'f2': fn(usize) -> u8
+            151..160 'f2.test()': bool
+            166..168 'f3': fn(u8, u8) -> &u8
+            166..175 'f3.test()': bool
         "#]],
     );
 }
@@ -2951,9 +2722,7 @@ fn test(f1: fn(), f2: fn(usize) -> u8, f3: fn(u8, u8) -> &u8) {
 fn builtin_sized() {
     check_infer_with_mismatches(
         r#"
-#[lang = "sized"]
-trait Sized {}
-
+//- minicore: sized
 trait Test { fn test(&self) -> bool; }
 impl<T: Sized> Test for T {}
 
@@ -2964,22 +2733,22 @@ fn test() {
     (1u8, *"foo").test(); // not Sized
 }"#,
         expect![[r#"
-            56..60 'self': &Self
-            113..228 '{     ...ized }': ()
-            119..122 '1u8': u8
-            119..129 '1u8.test()': bool
-            135..150 '(*"foo").test()': {unknown}
-            136..142 '*"foo"': str
-            137..142 '"foo"': &str
-            169..179 '(1u8, 1u8)': (u8, u8)
-            169..186 '(1u8, ...test()': bool
-            170..173 '1u8': u8
-            175..178 '1u8': u8
-            192..205 '(1u8, *"foo")': (u8, str)
-            192..212 '(1u8, ...test()': {unknown}
-            193..196 '1u8': u8
-            198..204 '*"foo"': str
-            199..204 '"foo"': &str
+            22..26 'self': &Self
+            79..194 '{     ...ized }': ()
+            85..88 '1u8': u8
+            85..95 '1u8.test()': bool
+            101..116 '(*"foo").test()': {unknown}
+            102..108 '*"foo"': str
+            103..108 '"foo"': &str
+            135..145 '(1u8, 1u8)': (u8, u8)
+            135..152 '(1u8, ...test()': bool
+            136..139 '1u8': u8
+            141..144 '1u8': u8
+            158..171 '(1u8, *"foo")': (u8, str)
+            158..178 '(1u8, ...test()': {unknown}
+            159..162 '1u8': u8
+            164..170 '*"foo"': str
+            165..170 '"foo"': &str
         "#]],
     );
 }
@@ -3064,45 +2833,23 @@ fn foo() {
 fn infer_fn_trait_arg() {
     check_infer_with_mismatches(
         r#"
-        //- /lib.rs deps:std
-
-        #[lang = "fn_once"]
-        pub trait FnOnce<Args> {
-            type Output;
-
-            extern "rust-call" fn call_once(&self, args: Args) -> Self::Output;
-        }
-
-        #[lang = "fn"]
-        pub trait Fn<Args>:FnOnce<Args> {
-            extern "rust-call" fn call(&self, args: Args) -> Self::Output;
-        }
-
-        enum Option<T> {
-            None,
-            Some(T)
-        }
-
-        fn foo<F, T>(f: F) -> T
-        where
-            F: Fn(Option<i32>) -> T,
-        {
-            let s = None;
-            f(s)
-        }
-        "#,
+//- minicore: fn, option
+fn foo<F, T>(f: F) -> T
+where
+    F: Fn(Option<i32>) -> T,
+{
+    let s = None;
+    f(s)
+}
+"#,
         expect![[r#"
-            101..105 'self': &Self
-            107..111 'args': Args
-            220..224 'self': &Self
-            226..230 'args': Args
-            313..314 'f': F
-            359..389 '{     ...f(s) }': T
-            369..370 's': Option<i32>
-            373..377 'None': Option<i32>
-            383..384 'f': F
-            383..387 'f(s)': T
-            385..386 's': Option<i32>
+            13..14 'f': F
+            59..89 '{     ...f(s) }': T
+            69..70 's': Option<i32>
+            73..77 'None': Option<i32>
+            83..84 'f': F
+            83..87 'f(s)': T
+            85..86 's': Option<i32>
         "#]],
     );
 }
@@ -3112,28 +2859,13 @@ fn infer_box_fn_arg() {
     // The type mismatch is because we don't define Unsize and CoerceUnsized
     check_infer_with_mismatches(
         r#"
-//- /lib.rs deps:std
-
-#[lang = "fn_once"]
-pub trait FnOnce<Args> {
-    type Output;
-
-    extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-}
-
-#[lang = "deref"]
-pub trait Deref {
-    type Target: ?Sized;
-
-    fn deref(&self) -> &Self::Target;
-}
-
+//- minicore: fn, deref, option
 #[lang = "owned_box"]
 pub struct Box<T: ?Sized> {
     inner: *mut T,
 }
 
-impl<T: ?Sized> Deref for Box<T> {
+impl<T: ?Sized> core::ops::Deref for Box<T> {
     type Target = T;
 
     fn deref(&self) -> &T {
@@ -3141,38 +2873,30 @@ impl<T: ?Sized> Deref for Box<T> {
     }
 }
 
-enum Option<T> {
-    None,
-    Some(T)
-}
-
 fn foo() {
-    let s = Option::None;
+    let s = None;
     let f: Box<dyn FnOnce(&Option<i32>)> = box (|ps| {});
     f(&s);
 }"#,
         expect![[r#"
-            100..104 'self': Self
-            106..110 'args': Args
-            214..218 'self': &Self
-            384..388 'self': &Box<T>
-            396..423 '{     ...     }': &T
-            406..417 '&self.inner': &*mut T
-            407..411 'self': &Box<T>
-            407..417 'self.inner': *mut T
-            478..576 '{     ...&s); }': ()
-            488..489 's': Option<i32>
-            492..504 'Option::None': Option<i32>
-            514..515 'f': Box<dyn FnOnce(&Option<i32>)>
-            549..562 'box (|ps| {})': Box<|{unknown}| -> ()>
-            554..561 '|ps| {}': |{unknown}| -> ()
-            555..557 'ps': {unknown}
-            559..561 '{}': ()
-            568..569 'f': Box<dyn FnOnce(&Option<i32>)>
-            568..573 'f(&s)': ()
-            570..572 '&s': &Option<i32>
-            571..572 's': Option<i32>
-            549..562: expected Box<dyn FnOnce(&Option<i32>)>, got Box<|{unknown}| -> ()>
+            154..158 'self': &Box<T>
+            166..193 '{     ...     }': &T
+            176..187 '&self.inner': &*mut T
+            177..181 'self': &Box<T>
+            177..187 'self.inner': *mut T
+            206..296 '{     ...&s); }': ()
+            216..217 's': Option<i32>
+            220..224 'None': Option<i32>
+            234..235 'f': Box<dyn FnOnce(&Option<i32>)>
+            269..282 'box (|ps| {})': Box<|{unknown}| -> ()>
+            274..281 '|ps| {}': |{unknown}| -> ()
+            275..277 'ps': {unknown}
+            279..281 '{}': ()
+            288..289 'f': Box<dyn FnOnce(&Option<i32>)>
+            288..293 'f(&s)': ()
+            290..292 '&s': &Option<i32>
+            291..292 's': Option<i32>
+            269..282: expected Box<dyn FnOnce(&Option<i32>)>, got Box<|{unknown}| -> ()>
         "#]],
     );
 }
@@ -3181,17 +2905,7 @@ fn foo() {
 fn infer_dyn_fn_output() {
     check_types(
         r#"
-#[lang = "fn_once"]
-pub trait FnOnce<Args> {
-    type Output;
-    extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-}
-
-#[lang = "fn"]
-pub trait Fn<Args>: FnOnce<Args> {
-    extern "rust-call" fn call(&self, args: Args) -> Self::Output;
-}
-
+//- minicore: fn
 fn foo() {
     let f: &dyn Fn() -> i32;
     f();
@@ -3204,12 +2918,7 @@ fn foo() {
 fn infer_dyn_fn_once_output() {
     check_types(
         r#"
-#[lang = "fn_once"]
-pub trait FnOnce<Args> {
-    type Output;
-    extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-}
-
+//- minicore: fn
 fn foo() {
     let f: dyn FnOnce() -> i32;
     f();
@@ -3230,7 +2939,7 @@ fn test() {
     S.get(1);
   //^^^^^^^^ u128
     S.get(1.);
-  //^^^^^^^^ f32
+  //^^^^^^^^^ f32
 }
         "#,
     );
@@ -3644,20 +3353,16 @@ fn main() {
 fn fn_returning_unit() {
     check_infer_with_mismatches(
         r#"
-#[lang = "fn_once"]
-trait FnOnce<Args> {
-    type Output;
-}
-
+//- minicore: fn
 fn test<F: FnOnce()>(f: F) {
     let _: () = f();
 }"#,
         expect![[r#"
-            82..83 'f': F
-            88..112 '{     ...f(); }': ()
-            98..99 '_': ()
-            106..107 'f': F
-            106..109 'f()': ()
+            21..22 'f': F
+            27..51 '{     ...f(); }': ()
+            37..38 '_': ()
+            45..46 'f': F
+            45..48 'f()': ()
         "#]],
     );
 }
@@ -3696,16 +3401,7 @@ impl foo::Foo for u32 {
 fn infer_async_ret_type() {
     check_types(
         r#"
-//- /main.rs crate:main deps:core
-
-enum Result<T, E> {
-    Ok(T),
-    Err(E),
-}
-
-use Result::*;
-
-
+//- minicore: future, result
 struct Fooey;
 
 impl Fooey {
@@ -3718,31 +3414,21 @@ trait Convert {
     fn new() -> Self;
 }
 impl Convert for u32 {
-    fn new() -> Self {
-        0
-    }
+    fn new() -> Self { 0 }
 }
 
 async fn get_accounts() -> Result<u32, ()> {
     let ret = Fooey.collect();
-    //                      ^ u32
+    //        ^^^^^^^^^^^^^^^ u32
     Ok(ret)
 }
-
-//- /core.rs crate:core
-#[prelude_import] use future::*;
-mod future {
-    #[lang = "future_trait"]
-    trait Future {
-        type Output;
-    }
-}
 "#,
     );
 }
 
 #[test]
 fn local_impl_1() {
+    check!(block_local_impls);
     check_types(
         r#"
 trait Trait<T> {
@@ -3752,7 +3438,7 @@ trait Trait<T> {
 fn test() {
     struct S;
     impl Trait<u32> for S {
-        fn foo(&self) { 0 }
+        fn foo(&self) -> u32 { 0 }
     }
 
     S.foo();
@@ -3764,6 +3450,7 @@ fn test() {
 
 #[test]
 fn local_impl_2() {
+    check!(block_local_impls);
     check_types(
         r#"
 struct S;
@@ -3773,7 +3460,7 @@ fn test() {
         fn foo(&self) -> T;
     }
     impl Trait<u32> for S {
-        fn foo(&self) { 0 }
+        fn foo(&self) -> u32 { 0 }
     }
 
     S.foo();
@@ -3785,6 +3472,7 @@ fn test() {
 
 #[test]
 fn local_impl_3() {
+    check!(block_local_impls);
     check_types(
         r#"
 trait Trait<T> {
@@ -3797,7 +3485,7 @@ fn test() {
         struct S2;
 
         impl Trait<S1> for S2 {
-            fn foo(&self) { S1 }
+            fn foo(&self) -> S1 { S1 }
         }
 
         S2.foo();
diff --git a/crates/ide/Cargo.toml b/crates/ide/Cargo.toml
index f12928225..0e8447394 100644
--- a/crates/ide/Cargo.toml
+++ b/crates/ide/Cargo.toml
@@ -29,6 +29,7 @@ ide_db = { path = "../ide_db", version = "0.0.0" }
 cfg = { path = "../cfg", version = "0.0.0" }
 profile = { path = "../profile", version = "0.0.0" }
 ide_assists = { path = "../ide_assists", version = "0.0.0" }
+ide_diagnostics = { path = "../ide_diagnostics", version = "0.0.0" }
 ide_ssr = { path = "../ide_ssr", version = "0.0.0" }
 ide_completion = { path = "../ide_completion", version = "0.0.0" }
 
diff --git a/crates/ide/src/diagnostics.rs b/crates/ide/src/diagnostics.rs
deleted file mode 100644
index 815a633e5..000000000
--- a/crates/ide/src/diagnostics.rs
+++ /dev/null
@@ -1,498 +0,0 @@
-//! Collects diagnostics & fixits  for a single file.
-//!
-//! The tricky bit here is that diagnostics are produced by hir in terms of
-//! macro-expanded files, but we need to present them to the users in terms of
-//! original files. So we need to map the ranges.
-
-mod break_outside_of_loop;
-mod inactive_code;
-mod incorrect_case;
-mod macro_error;
-mod mismatched_arg_count;
-mod missing_fields;
-mod missing_match_arms;
-mod missing_ok_or_some_in_tail_expr;
-mod missing_unsafe;
-mod no_such_field;
-mod remove_this_semicolon;
-mod replace_filter_map_next_with_find_map;
-mod unimplemented_builtin_macro;
-mod unlinked_file;
-mod unresolved_extern_crate;
-mod unresolved_import;
-mod unresolved_macro_call;
-mod unresolved_module;
-mod unresolved_proc_macro;
-
-mod field_shorthand;
-
-use hir::{diagnostics::AnyDiagnostic, Semantics};
-use ide_assists::AssistResolveStrategy;
-use ide_db::{base_db::SourceDatabase, RootDatabase};
-use itertools::Itertools;
-use rustc_hash::FxHashSet;
-use syntax::{
-    ast::{self, AstNode},
-    SyntaxNode, TextRange,
-};
-use text_edit::TextEdit;
-use unlinked_file::UnlinkedFile;
-
-use crate::{Assist, AssistId, AssistKind, FileId, Label, SourceChange};
-
-#[derive(Copy, Clone, Debug, PartialEq)]
-pub struct DiagnosticCode(pub &'static str);
-
-impl DiagnosticCode {
-    pub fn as_str(&self) -> &str {
-        self.0
-    }
-}
-
-#[derive(Debug)]
-pub struct Diagnostic {
-    pub code: DiagnosticCode,
-    pub message: String,
-    pub range: TextRange,
-    pub severity: Severity,
-    pub unused: bool,
-    pub experimental: bool,
-    pub fixes: Option<Vec<Assist>>,
-}
-
-impl Diagnostic {
-    fn new(code: &'static str, message: impl Into<String>, range: TextRange) -> Diagnostic {
-        let message = message.into();
-        Diagnostic {
-            code: DiagnosticCode(code),
-            message,
-            range,
-            severity: Severity::Error,
-            unused: false,
-            experimental: false,
-            fixes: None,
-        }
-    }
-
-    fn experimental(mut self) -> Diagnostic {
-        self.experimental = true;
-        self
-    }
-
-    fn severity(mut self, severity: Severity) -> Diagnostic {
-        self.severity = severity;
-        self
-    }
-
-    fn with_fixes(mut self, fixes: Option<Vec<Assist>>) -> Diagnostic {
-        self.fixes = fixes;
-        self
-    }
-
-    fn with_unused(mut self, unused: bool) -> Diagnostic {
-        self.unused = unused;
-        self
-    }
-}
-
-#[derive(Debug, Copy, Clone)]
-pub enum Severity {
-    Error,
-    WeakWarning,
-}
-
-#[derive(Default, Debug, Clone)]
-pub struct DiagnosticsConfig {
-    pub disable_experimental: bool,
-    pub disabled: FxHashSet<String>,
-}
-
-struct DiagnosticsContext<'a> {
-    config: &'a DiagnosticsConfig,
-    sema: Semantics<'a, RootDatabase>,
-    resolve: &'a AssistResolveStrategy,
-}
-
-pub(crate) fn diagnostics(
-    db: &RootDatabase,
-    config: &DiagnosticsConfig,
-    resolve: &AssistResolveStrategy,
-    file_id: FileId,
-) -> Vec<Diagnostic> {
-    let _p = profile::span("diagnostics");
-    let sema = Semantics::new(db);
-    let parse = db.parse(file_id);
-    let mut res = Vec::new();
-
-    // [#34344] Only take first 128 errors to prevent slowing down editor/ide, the number 128 is chosen arbitrarily.
-    res.extend(
-        parse.errors().iter().take(128).map(|err| {
-            Diagnostic::new("syntax-error", format!("Syntax Error: {}", err), err.range())
-        }),
-    );
-
-    for node in parse.tree().syntax().descendants() {
-        check_unnecessary_braces_in_use_statement(&mut res, file_id, &node);
-        field_shorthand::check(&mut res, file_id, &node);
-    }
-
-    let mut diags = Vec::new();
-    let module = sema.to_module_def(file_id);
-    if let Some(m) = module {
-        m.diagnostics(db, &mut diags)
-    }
-
-    let ctx = DiagnosticsContext { config, sema, resolve };
-    if module.is_none() {
-        let d = UnlinkedFile { file: file_id };
-        let d = unlinked_file::unlinked_file(&ctx, &d);
-        res.push(d)
-    }
-
-    for diag in diags {
-        #[rustfmt::skip]
-        let d = match diag {
-            AnyDiagnostic::BreakOutsideOfLoop(d) => break_outside_of_loop::break_outside_of_loop(&ctx, &d),
-            AnyDiagnostic::IncorrectCase(d) => incorrect_case::incorrect_case(&ctx, &d),
-            AnyDiagnostic::MacroError(d) => macro_error::macro_error(&ctx, &d),
-            AnyDiagnostic::MismatchedArgCount(d) => mismatched_arg_count::mismatched_arg_count(&ctx, &d),
-            AnyDiagnostic::MissingFields(d) => missing_fields::missing_fields(&ctx, &d),
-            AnyDiagnostic::MissingMatchArms(d) => missing_match_arms::missing_match_arms(&ctx, &d),
-            AnyDiagnostic::MissingOkOrSomeInTailExpr(d) => missing_ok_or_some_in_tail_expr::missing_ok_or_some_in_tail_expr(&ctx, &d),
-            AnyDiagnostic::MissingUnsafe(d) => missing_unsafe::missing_unsafe(&ctx, &d),
-            AnyDiagnostic::NoSuchField(d) => no_such_field::no_such_field(&ctx, &d),
-            AnyDiagnostic::RemoveThisSemicolon(d) => remove_this_semicolon::remove_this_semicolon(&ctx, &d),
-            AnyDiagnostic::ReplaceFilterMapNextWithFindMap(d) => replace_filter_map_next_with_find_map::replace_filter_map_next_with_find_map(&ctx, &d),
-            AnyDiagnostic::UnimplementedBuiltinMacro(d) => unimplemented_builtin_macro::unimplemented_builtin_macro(&ctx, &d),
-            AnyDiagnostic::UnresolvedExternCrate(d) => unresolved_extern_crate::unresolved_extern_crate(&ctx, &d),
-            AnyDiagnostic::UnresolvedImport(d) => unresolved_import::unresolved_import(&ctx, &d),
-            AnyDiagnostic::UnresolvedMacroCall(d) => unresolved_macro_call::unresolved_macro_call(&ctx, &d),
-            AnyDiagnostic::UnresolvedModule(d) => unresolved_module::unresolved_module(&ctx, &d),
-            AnyDiagnostic::UnresolvedProcMacro(d) => unresolved_proc_macro::unresolved_proc_macro(&ctx, &d),
-
-            AnyDiagnostic::InactiveCode(d) => match inactive_code::inactive_code(&ctx, &d) {
-                Some(it) => it,
-                None => continue,
-            }
-        };
-        res.push(d)
-    }
-
-    res.retain(|d| {
-        !ctx.config.disabled.contains(d.code.as_str())
-            && !(ctx.config.disable_experimental && d.experimental)
-    });
-
-    res
-}
-
-fn check_unnecessary_braces_in_use_statement(
-    acc: &mut Vec<Diagnostic>,
-    file_id: FileId,
-    node: &SyntaxNode,
-) -> Option<()> {
-    let use_tree_list = ast::UseTreeList::cast(node.clone())?;
-    if let Some((single_use_tree,)) = use_tree_list.use_trees().collect_tuple() {
-        // If there is a comment inside the bracketed `use`,
-        // assume it is a commented out module path and don't show diagnostic.
-        if use_tree_list.has_inner_comment() {
-            return Some(());
-        }
-
-        let use_range = use_tree_list.syntax().text_range();
-        let edit =
-            text_edit_for_remove_unnecessary_braces_with_self_in_use_statement(&single_use_tree)
-                .unwrap_or_else(|| {
-                    let to_replace = single_use_tree.syntax().text().to_string();
-                    let mut edit_builder = TextEdit::builder();
-                    edit_builder.delete(use_range);
-                    edit_builder.insert(use_range.start(), to_replace);
-                    edit_builder.finish()
-                });
-
-        acc.push(
-            Diagnostic::new(
-                "unnecessary-braces",
-                "Unnecessary braces in use statement".to_string(),
-                use_range,
-            )
-            .severity(Severity::WeakWarning)
-            .with_fixes(Some(vec![fix(
-                "remove_braces",
-                "Remove unnecessary braces",
-                SourceChange::from_text_edit(file_id, edit),
-                use_range,
-            )])),
-        );
-    }
-
-    Some(())
-}
-
-fn text_edit_for_remove_unnecessary_braces_with_self_in_use_statement(
-    single_use_tree: &ast::UseTree,
-) -> Option<TextEdit> {
-    let use_tree_list_node = single_use_tree.syntax().parent()?;
-    if single_use_tree.path()?.segment()?.self_token().is_some() {
-        let start = use_tree_list_node.prev_sibling_or_token()?.text_range().start();
-        let end = use_tree_list_node.text_range().end();
-        return Some(TextEdit::delete(TextRange::new(start, end)));
-    }
-    None
-}
-
-fn fix(id: &'static str, label: &str, source_change: SourceChange, target: TextRange) -> Assist {
-    let mut res = unresolved_fix(id, label, target);
-    res.source_change = Some(source_change);
-    res
-}
-
-fn unresolved_fix(id: &'static str, label: &str, target: TextRange) -> Assist {
-    assert!(!id.contains(' '));
-    Assist {
-        id: AssistId(id, AssistKind::QuickFix),
-        label: Label::new(label),
-        group: None,
-        target,
-        source_change: None,
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use expect_test::Expect;
-    use ide_assists::AssistResolveStrategy;
-    use stdx::trim_indent;
-    use test_utils::{assert_eq_text, extract_annotations};
-
-    use crate::{fixture, DiagnosticsConfig};
-
-    /// Takes a multi-file input fixture with annotated cursor positions,
-    /// and checks that:
-    ///  * a diagnostic is produced
-    ///  * the first diagnostic fix trigger range touches the input cursor position
-    ///  * that the contents of the file containing the cursor match `after` after the diagnostic fix is applied
-    #[track_caller]
-    pub(crate) fn check_fix(ra_fixture_before: &str, ra_fixture_after: &str) {
-        check_nth_fix(0, ra_fixture_before, ra_fixture_after);
-    }
-    /// Takes a multi-file input fixture with annotated cursor positions,
-    /// and checks that:
-    ///  * a diagnostic is produced
-    ///  * every diagnostic fixes trigger range touches the input cursor position
-    ///  * that the contents of the file containing the cursor match `after` after each diagnostic fix is applied
-    pub(crate) fn check_fixes(ra_fixture_before: &str, ra_fixtures_after: Vec<&str>) {
-        for (i, ra_fixture_after) in ra_fixtures_after.iter().enumerate() {
-            check_nth_fix(i, ra_fixture_before, ra_fixture_after)
-        }
-    }
-
-    #[track_caller]
-    fn check_nth_fix(nth: usize, ra_fixture_before: &str, ra_fixture_after: &str) {
-        let after = trim_indent(ra_fixture_after);
-
-        let (analysis, file_position) = fixture::position(ra_fixture_before);
-        let diagnostic = analysis
-            .diagnostics(
-                &DiagnosticsConfig::default(),
-                AssistResolveStrategy::All,
-                file_position.file_id,
-            )
-            .unwrap()
-            .pop()
-            .expect("no diagnostics");
-        let fix = &diagnostic.fixes.expect("diagnostic misses fixes")[nth];
-        let actual = {
-            let source_change = fix.source_change.as_ref().unwrap();
-            let file_id = *source_change.source_file_edits.keys().next().unwrap();
-            let mut actual = analysis.file_text(file_id).unwrap().to_string();
-
-            for edit in source_change.source_file_edits.values() {
-                edit.apply(&mut actual);
-            }
-            actual
-        };
-
-        assert_eq_text!(&after, &actual);
-        assert!(
-            fix.target.contains_inclusive(file_position.offset),
-            "diagnostic fix range {:?} does not touch cursor position {:?}",
-            fix.target,
-            file_position.offset
-        );
-    }
-
-    /// Checks that there's a diagnostic *without* fix at `$0`.
-    pub(crate) fn check_no_fix(ra_fixture: &str) {
-        let (analysis, file_position) = fixture::position(ra_fixture);
-        let diagnostic = analysis
-            .diagnostics(
-                &DiagnosticsConfig::default(),
-                AssistResolveStrategy::All,
-                file_position.file_id,
-            )
-            .unwrap()
-            .pop()
-            .unwrap();
-        assert!(diagnostic.fixes.is_none(), "got a fix when none was expected: {:?}", diagnostic);
-    }
-
-    pub(crate) fn check_expect(ra_fixture: &str, expect: Expect) {
-        let (analysis, file_id) = fixture::file(ra_fixture);
-        let diagnostics = analysis
-            .diagnostics(&DiagnosticsConfig::default(), AssistResolveStrategy::All, file_id)
-            .unwrap();
-        expect.assert_debug_eq(&diagnostics)
-    }
-
-    #[track_caller]
-    pub(crate) fn check_diagnostics(ra_fixture: &str) {
-        let mut config = DiagnosticsConfig::default();
-        config.disabled.insert("inactive-code".to_string());
-        check_diagnostics_with_config(config, ra_fixture)
-    }
-
-    #[track_caller]
-    pub(crate) fn check_diagnostics_with_config(config: DiagnosticsConfig, ra_fixture: &str) {
-        let (analysis, files) = fixture::files(ra_fixture);
-        for file_id in files {
-            let diagnostics =
-                analysis.diagnostics(&config, AssistResolveStrategy::All, file_id).unwrap();
-
-            let expected = extract_annotations(&*analysis.file_text(file_id).unwrap());
-            let mut actual =
-                diagnostics.into_iter().map(|d| (d.range, d.message)).collect::<Vec<_>>();
-            actual.sort_by_key(|(range, _)| range.start());
-            assert_eq!(expected, actual);
-        }
-    }
-
-    #[test]
-    fn test_check_unnecessary_braces_in_use_statement() {
-        check_diagnostics(
-            r#"
-use a;
-use a::{c, d::e};
-
-mod a {
-    mod c {}
-    mod d {
-        mod e {}
-    }
-}
-"#,
-        );
-        check_diagnostics(
-            r#"
-use a;
-use a::{
-    c,
-    // d::e
-};
-
-mod a {
-    mod c {}
-    mod d {
-        mod e {}
-    }
-}
-"#,
-        );
-        check_fix(
-            r"
-            mod b {}
-            use {$0b};
-            ",
-            r"
-            mod b {}
-            use b;
-            ",
-        );
-        check_fix(
-            r"
-            mod b {}
-            use {b$0};
-            ",
-            r"
-            mod b {}
-            use b;
-            ",
-        );
-        check_fix(
-            r"
-            mod a { mod c {} }
-            use a::{c$0};
-            ",
-            r"
-            mod a { mod c {} }
-            use a::c;
-            ",
-        );
-        check_fix(
-            r"
-            mod a {}
-            use a::{self$0};
-            ",
-            r"
-            mod a {}
-            use a;
-            ",
-        );
-        check_fix(
-            r"
-            mod a { mod c {} mod d { mod e {} } }
-            use a::{c, d::{e$0}};
-            ",
-            r"
-            mod a { mod c {} mod d { mod e {} } }
-            use a::{c, d::e};
-            ",
-        );
-    }
-
-    #[test]
-    fn test_disabled_diagnostics() {
-        let mut config = DiagnosticsConfig::default();
-        config.disabled.insert("unresolved-module".into());
-
-        let (analysis, file_id) = fixture::file(r#"mod foo;"#);
-
-        let diagnostics =
-            analysis.diagnostics(&config, AssistResolveStrategy::All, file_id).unwrap();
-        assert!(diagnostics.is_empty());
-
-        let diagnostics = analysis
-            .diagnostics(&DiagnosticsConfig::default(), AssistResolveStrategy::All, file_id)
-            .unwrap();
-        assert!(!diagnostics.is_empty());
-    }
-
-    #[test]
-    fn import_extern_crate_clash_with_inner_item() {
-        // This is more of a resolver test, but doesn't really work with the hir_def testsuite.
-
-        check_diagnostics(
-            r#"
-//- /lib.rs crate:lib deps:jwt
-mod permissions;
-
-use permissions::jwt;
-
-fn f() {
-    fn inner() {}
-    jwt::Claims {}; // should resolve to the local one with 0 fields, and not get a diagnostic
-}
-
-//- /permissions.rs
-pub mod jwt  {
-    pub struct Claims {}
-}
-
-//- /jwt/lib.rs crate:jwt
-pub struct Claims {
-    field: u8,
-}
-        "#,
-        );
-    }
-}
diff --git a/crates/ide/src/display/navigation_target.rs b/crates/ide/src/display/navigation_target.rs
index b75ec411c..455b32456 100644
--- a/crates/ide/src/display/navigation_target.rs
+++ b/crates/ide/src/display/navigation_target.rs
@@ -442,10 +442,10 @@ impl TryToNav for hir::TypeParam {
     fn try_to_nav(&self, db: &RootDatabase) -> Option<NavigationTarget> {
         let src = self.source(db)?;
         let full_range = match &src.value {
-            Either::Left(it) => it
+            Either::Left(type_param) => type_param.syntax().text_range(),
+            Either::Right(trait_) => trait_
                 .name()
-                .map_or_else(|| it.syntax().text_range(), |name| name.syntax().text_range()),
-            Either::Right(it) => it.syntax().text_range(),
+                .map_or_else(|| trait_.syntax().text_range(), |name| name.syntax().text_range()),
         };
         let focus_range = match &src.value {
             Either::Left(it) => it.name(),
diff --git a/crates/ide/src/doc_links.rs b/crates/ide/src/doc_links.rs
index 57ae9455b..7ac0118fe 100644
--- a/crates/ide/src/doc_links.rs
+++ b/crates/ide/src/doc_links.rs
@@ -241,6 +241,10 @@ fn get_doc_link(db: &RootDatabase, definition: Definition) -> Option<String> {
         Definition::ModuleDef(ModuleDef::Module(module)) => module.krate(),
         _ => definition.module(db)?.krate(),
     };
+    // FIXME: using import map doesn't make sense here. What we want here is
+    // canonical path. What import map returns is the shortest path suitable for
+    // import. See this test:
+    cov_mark::hit!(test_reexport_order);
     let import_map = db.import_map(krate.into());
 
     let mut base = krate.display_name(db)?.to_string();
@@ -642,13 +646,15 @@ pub mod foo {
         )
     }
 
-    // FIXME: ImportMap will return re-export paths instead of public module
-    // paths. The correct path to documentation will never be a re-export.
-    // This problem stops us from resolving stdlib items included in the prelude
-    // such as `Option::Some` correctly.
-    #[ignore = "ImportMap may return re-exports"]
     #[test]
     fn test_reexport_order() {
+        cov_mark::check!(test_reexport_order);
+        // FIXME: This should return
+        //
+        //    https://docs.rs/test/*/test/wrapper/modulestruct.Item.html
+        //
+        // That is, we should point inside the module, rather than at the
+        // re-export.
         check(
             r#"
 pub mod wrapper {
@@ -663,7 +669,7 @@ fn foo() {
     let bar: wrapper::It$0em;
 }
         "#,
-            expect![[r#"https://docs.rs/test/*/test/wrapper/module/struct.Item.html"#]],
+            expect![[r#"https://docs.rs/test/*/test/wrapper/struct.Item.html"#]],
         )
     }
 }
diff --git a/crates/ide/src/fixture.rs b/crates/ide/src/fixture.rs
index 38e2e866b..cf679edd3 100644
--- a/crates/ide/src/fixture.rs
+++ b/crates/ide/src/fixture.rs
@@ -12,14 +12,6 @@ pub(crate) fn file(ra_fixture: &str) -> (Analysis, FileId) {
     (host.analysis(), change_fixture.files[0])
 }
 
-/// Creates analysis for many files.
-pub(crate) fn files(ra_fixture: &str) -> (Analysis, Vec<FileId>) {
-    let mut host = AnalysisHost::default();
-    let change_fixture = ChangeFixture::parse(ra_fixture);
-    host.db.apply_change(change_fixture.change);
-    (host.analysis(), change_fixture.files)
-}
-
 /// Creates analysis from a multi-file fixture, returns positions marked with $0.
 pub(crate) fn position(ra_fixture: &str) -> (Analysis, FilePosition) {
     let mut host = AnalysisHost::default();
diff --git a/crates/ide/src/goto_definition.rs b/crates/ide/src/goto_definition.rs
index 8dd643a0f..d8e0dc4d5 100644
--- a/crates/ide/src/goto_definition.rs
+++ b/crates/ide/src/goto_definition.rs
@@ -1130,15 +1130,15 @@ fn foo<'foobar>(_: &'foobar ()) {
     }
 
     #[test]
-    #[ignore] // requires the HIR to somehow track these hrtb lifetimes
     fn goto_lifetime_hrtb() {
-        check(
+        // FIXME: requires the HIR to somehow track these hrtb lifetimes
+        check_unresolved(
             r#"trait Foo<T> {}
 fn foo<T>() where for<'a> T: Foo<&'a$0 (u8, u16)>, {}
                     //^^
 "#,
         );
-        check(
+        check_unresolved(
             r#"trait Foo<T> {}
 fn foo<T>() where for<'a$0> T: Foo<&'a (u8, u16)>, {}
                     //^^
@@ -1147,9 +1147,9 @@ fn foo<T>() where for<'a$0> T: Foo<&'a (u8, u16)>, {}
     }
 
     #[test]
-    #[ignore] // requires ForTypes to be implemented
     fn goto_lifetime_hrtb_for_type() {
-        check(
+        // FIXME: requires ForTypes to be implemented
+        check_unresolved(
             r#"trait Foo<T> {}
 fn foo<T>() where T: for<'a> Foo<&'a$0 (u8, u16)>, {}
                        //^^
diff --git a/crates/ide/src/goto_implementation.rs b/crates/ide/src/goto_implementation.rs
index 0013820b4..07686017d 100644
--- a/crates/ide/src/goto_implementation.rs
+++ b/crates/ide/src/goto_implementation.rs
@@ -236,15 +236,10 @@ impl T for &Foo {}
     fn goto_implementation_to_builtin_derive() {
         check(
             r#"
+//- minicore: copy, derive
   #[derive(Copy)]
 //^^^^^^^^^^^^^^^
 struct Foo$0;
-
-mod marker {
-    trait Copy {}
-}
-#[rustc_builtin_macro]
-macro Copy {}
 "#,
         );
     }
diff --git a/crates/ide/src/goto_type_definition.rs b/crates/ide/src/goto_type_definition.rs
index 004d9cb68..43cffefe5 100644
--- a/crates/ide/src/goto_type_definition.rs
+++ b/crates/ide/src/goto_type_definition.rs
@@ -33,13 +33,23 @@ pub(crate) fn goto_type_definition(
                 ast::SelfParam(it) => sema.type_of_self(&it)?,
                 ast::Type(it) => sema.resolve_type(&it)?,
                 ast::RecordField(it) => sema.to_def(&it).map(|d| d.ty(db.upcast()))?,
+                ast::RecordField(it) => sema.to_def(&it).map(|d| d.ty(db.upcast()))?,
+                // can't match on RecordExprField directly as `ast::Expr` will match an iteration too early otherwise
+                ast::NameRef(it) => {
+                    if let Some(record_field) = ast::RecordExprField::for_name_ref(&it) {
+                        let (_, _, ty) = sema.resolve_record_field(&record_field)?;
+                        ty
+                    } else {
+                        let record_field = ast::RecordPatField::for_field_name_ref(&it)?;
+                        sema.resolve_record_pat_field(&record_field)?.ty(db)
+                    }
+                },
                 _ => return None,
             }
         };
 
         Some((ty, node))
     })?;
-
     let adt_def = ty.autoderef(db).filter_map(|ty| ty.as_adt()).last()?;
 
     let nav = adt_def.try_to_nav(db)?;
@@ -88,6 +98,54 @@ fn foo() {
     }
 
     #[test]
+    fn goto_type_definition_record_expr_field() {
+        check(
+            r#"
+struct Bar;
+    // ^^^
+struct Foo { foo: Bar }
+fn foo() {
+    Foo { foo$0 }
+}
+"#,
+        );
+        check(
+            r#"
+struct Bar;
+    // ^^^
+struct Foo { foo: Bar }
+fn foo() {
+    Foo { foo$0: Bar }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn goto_type_definition_record_pat_field() {
+        check(
+            r#"
+struct Bar;
+    // ^^^
+struct Foo { foo: Bar }
+fn foo() {
+    let Foo { foo$0 };
+}
+"#,
+        );
+        check(
+            r#"
+struct Bar;
+    // ^^^
+struct Foo { foo: Bar }
+fn foo() {
+    let Foo { foo$0: bar };
+}
+"#,
+        );
+    }
+
+    #[test]
     fn goto_type_definition_works_simple_ref() {
         check(
             r#"
diff --git a/crates/ide/src/hover.rs b/crates/ide/src/hover.rs
index 4e1ab534b..0c1da8774 100644
--- a/crates/ide/src/hover.rs
+++ b/crates/ide/src/hover.rs
@@ -563,8 +563,6 @@ mod tests {
 
     use crate::fixture;
 
-    use super::*;
-
     fn check_hover_no_result(ra_fixture: &str) {
         let (analysis, position) = fixture::position(ra_fixture);
         assert!(analysis.hover(position, true, true, true).unwrap().is_none());
@@ -1816,9 +1814,10 @@ pub struct B$0ar
         );
     }
 
-    #[ignore = "path based links currently only support documentation on ModuleDef items"]
     #[test]
     fn test_hover_path_link_field() {
+        // FIXME: Should be
+        //  [Foo](https://docs.rs/test/*/test/struct.Foo.html)
         check(
             r#"
 pub struct Foo;
@@ -1840,7 +1839,7 @@ pub struct Bar {
 
                 ---
 
-                [Foo](https://docs.rs/test/*/test/struct.Foo.html)
+                [Foo](struct.Foo.html)
             "#]],
         );
     }
@@ -2254,7 +2253,7 @@ pub fn fo$0o() {}
                 case 13. collapsed link: foo
                 case 14. shortcut link: foo
                 case 15. inline without URL: foo
-                case 16. just escaped text: \[foo]
+                case 16. just escaped text: \[foo\]
                 case 17. inline link: Foo
 
                 [^example]: https://www.example.com/
@@ -2994,29 +2993,24 @@ fn foo(ar$0g: &impl Foo + Bar<S>) {}
     fn test_hover_async_block_impl_trait_has_goto_type_action() {
         check_actions(
             r#"
+//- minicore: future
 struct S;
 fn foo() {
     let fo$0o = async { S };
 }
-
-#[prelude_import] use future::*;
-mod future {
-    #[lang = "future_trait"]
-    pub trait Future { type Output; }
-}
 "#,
             expect![[r#"
                 [
                     GoToType(
                         [
                             HoverGotoTypeData {
-                                mod_path: "test::future::Future",
+                                mod_path: "core::future::Future",
                                 nav: NavigationTarget {
                                     file_id: FileId(
-                                        0,
+                                        1,
                                     ),
-                                    full_range: 101..163,
-                                    focus_range: 140..146,
+                                    full_range: 251..433,
+                                    focus_range: 290..296,
                                     name: "Future",
                                     kind: Trait,
                                     description: "pub trait Future",
@@ -3812,11 +3806,14 @@ use foo::bar::{self$0};
 
     #[test]
     fn hover_keyword() {
-        let ra_fixture = r#"//- /main.rs crate:main deps:std
-fn f() { retur$0n; }"#;
-        let fixture = format!("{}\n{}", ra_fixture, FamousDefs::FIXTURE);
         check(
-            &fixture,
+            r#"
+//- /main.rs crate:main deps:std
+fn f() { retur$0n; }
+//- /libstd.rs crate:std
+/// Docs for return_keyword
+mod return_keyword {}
+"#,
             expect![[r#"
                 *return*
 
@@ -3833,11 +3830,15 @@ fn f() { retur$0n; }"#;
 
     #[test]
     fn hover_builtin() {
-        let ra_fixture = r#"//- /main.rs crate:main deps:std
-cosnt _: &str$0 = ""; }"#;
-        let fixture = format!("{}\n{}", ra_fixture, FamousDefs::FIXTURE);
         check(
-            &fixture,
+            r#"
+//- /main.rs crate:main deps:std
+cosnt _: &str$0 = ""; }
+
+//- /libstd.rs crate:std
+/// Docs for prim_str
+mod prim_str {}
+"#,
             expect![[r#"
                 *str*
 
diff --git a/crates/ide/src/inlay_hints.rs b/crates/ide/src/inlay_hints.rs
index 9cd33d0e4..95f9edce4 100644
--- a/crates/ide/src/inlay_hints.rs
+++ b/crates/ide/src/inlay_hints.rs
@@ -434,7 +434,6 @@ fn get_callable(
 #[cfg(test)]
 mod tests {
     use expect_test::{expect, Expect};
-    use ide_db::helpers::FamousDefs;
     use test_utils::extract_annotations;
 
     use crate::{fixture, inlay_hints::InlayHintsConfig};
@@ -487,8 +486,6 @@ mod tests {
     }
 
     fn check_with_config(config: InlayHintsConfig, ra_fixture: &str) {
-        let ra_fixture =
-            format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
         let (analysis, file_id) = fixture::file(&ra_fixture);
         let expected = extract_annotations(&*analysis.file_text(file_id).unwrap());
         let inlay_hints = analysis.inlay_hints(file_id, &config).unwrap();
@@ -498,8 +495,6 @@ mod tests {
     }
 
     fn check_expect(config: InlayHintsConfig, ra_fixture: &str, expect: Expect) {
-        let ra_fixture =
-            format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
         let (analysis, file_id) = fixture::file(&ra_fixture);
         let inlay_hints = analysis.inlay_hints(file_id, &config).unwrap();
         expect.assert_debug_eq(&inlay_hints)
@@ -666,9 +661,7 @@ fn main() {
     fn function_call_parameter_hint() {
         check_params(
             r#"
-enum Option<T> { None, Some(T) }
-use Option::*;
-
+//- minicore: option
 struct FileId {}
 struct SmolStr {}
 
@@ -823,6 +816,7 @@ fn main() {
     fn shorten_iterators_in_associated_params() {
         check_types(
             r#"
+//- minicore: iterators
 use core::iter;
 
 pub struct SomeIter<T> {}
@@ -875,8 +869,7 @@ fn main() {
     fn fn_hints() {
         check_types(
             r#"
-trait Sized {}
-
+//- minicore: fn, sized
 fn foo() -> impl Fn() { loop {} }
 fn foo1() -> impl Fn(f64) { loop {} }
 fn foo2() -> impl Fn(f64, f64) { loop {} }
@@ -912,9 +905,7 @@ fn main() {
     fn unit_structs_have_no_type_hints() {
         check_types(
             r#"
-enum Result<T, E> { Ok(T), Err(E) }
-use Result::*;
-
+//- minicore: result
 struct SyntheticSyntax;
 
 fn main() {
@@ -966,9 +957,7 @@ fn main() {
     fn if_expr() {
         check_types(
             r#"
-enum Option<T> { None, Some(T) }
-use Option::*;
-
+//- minicore: option
 struct Test { a: Option<u32>, b: u8 }
 
 fn main() {
@@ -998,9 +987,7 @@ fn main() {
     fn while_expr() {
         check_types(
             r#"
-enum Option<T> { None, Some(T) }
-use Option::*;
-
+//- minicore: option
 struct Test { a: Option<u32>, b: u8 }
 
 fn main() {
@@ -1016,9 +1003,7 @@ fn main() {
     fn match_arm_list() {
         check_types(
             r#"
-enum Option<T> { None, Some(T) }
-use Option::*;
-
+//- minicore: option
 struct Test { a: Option<u32>, b: u8 }
 
 fn main() {
@@ -1073,6 +1058,7 @@ fn main() {
     fn complete_for_hint() {
         check_types(
             r#"
+//- minicore: iterator
 pub struct Vec<T> {}
 
 impl<T> Vec<T> {
@@ -1129,6 +1115,7 @@ fn main() {
     fn shorten_iterator_hints() {
         check_types(
             r#"
+//- minicore: iterators
 use core::iter;
 
 struct MyIter;
@@ -1230,12 +1217,12 @@ fn main() {
             expect![[r#"
                 [
                     InlayHint {
-                        range: 148..173,
+                        range: 147..172,
                         kind: ChainingHint,
                         label: "B",
                     },
                     InlayHint {
-                        range: 148..155,
+                        range: 147..154,
                         kind: ChainingHint,
                         label: "A",
                     },
@@ -1290,12 +1277,12 @@ fn main() {
             expect![[r#"
                 [
                     InlayHint {
-                        range: 144..191,
+                        range: 143..190,
                         kind: ChainingHint,
                         label: "C",
                     },
                     InlayHint {
-                        range: 144..180,
+                        range: 143..179,
                         kind: ChainingHint,
                         label: "B",
                     },
@@ -1335,12 +1322,12 @@ fn main() {
             expect![[r#"
                 [
                     InlayHint {
-                        range: 247..284,
+                        range: 246..283,
                         kind: ChainingHint,
                         label: "B<X<i32, bool>>",
                     },
                     InlayHint {
-                        range: 247..266,
+                        range: 246..265,
                         kind: ChainingHint,
                         label: "A<X<i32, bool>>",
                     },
@@ -1359,6 +1346,7 @@ fn main() {
                 max_length: None,
             },
             r#"
+//- minicore: iterators
 use core::iter;
 
 struct MyIter;
@@ -1381,22 +1369,22 @@ fn main() {
             expect![[r#"
                 [
                     InlayHint {
-                        range: 175..242,
+                        range: 174..241,
                         kind: ChainingHint,
                         label: "impl Iterator<Item = ()>",
                     },
                     InlayHint {
-                        range: 175..225,
+                        range: 174..224,
                         kind: ChainingHint,
                         label: "impl Iterator<Item = ()>",
                     },
                     InlayHint {
-                        range: 175..207,
+                        range: 174..206,
                         kind: ChainingHint,
                         label: "impl Iterator<Item = ()>",
                     },
                     InlayHint {
-                        range: 175..190,
+                        range: 174..189,
                         kind: ChainingHint,
                         label: "&mut MyIter",
                     },
diff --git a/crates/ide/src/join_lines.rs b/crates/ide/src/join_lines.rs
index 93d3760bf..ffa8bd182 100644
--- a/crates/ide/src/join_lines.rs
+++ b/crates/ide/src/join_lines.rs
@@ -197,7 +197,7 @@ fn join_single_use_tree(edit: &mut TextEditBuilder, token: &SyntaxToken) -> Opti
 }
 
 fn is_trailing_comma(left: SyntaxKind, right: SyntaxKind) -> bool {
-    matches!((left, right), (T![,], T![')']) | (T![,], T![']']))
+    matches!((left, right), (T![,], T![')'] | T![']']))
 }
 
 fn compute_ws(left: SyntaxKind, right: SyntaxKind) -> &'static str {
diff --git a/crates/ide/src/lib.rs b/crates/ide/src/lib.rs
index 8d0270319..3798f32cc 100644
--- a/crates/ide/src/lib.rs
+++ b/crates/ide/src/lib.rs
@@ -24,7 +24,6 @@ mod display;
 
 mod annotations;
 mod call_hierarchy;
-mod diagnostics;
 mod expand_macro;
 mod extend_selection;
 mod file_structure;
@@ -40,6 +39,7 @@ mod matching_brace;
 mod move_item;
 mod parent_module;
 mod references;
+mod rename;
 mod fn_references;
 mod runnables;
 mod ssr;
@@ -71,7 +71,6 @@ use crate::display::ToNav;
 pub use crate::{
     annotations::{Annotation, AnnotationConfig, AnnotationKind},
     call_hierarchy::CallItem,
-    diagnostics::{Diagnostic, DiagnosticsConfig, Severity},
     display::navigation_target::NavigationTarget,
     expand_macro::ExpandedMacro,
     file_structure::{StructureNode, StructureNodeKind},
@@ -81,7 +80,8 @@ pub use crate::{
     markup::Markup,
     move_item::Direction,
     prime_caches::PrimeCachesProgress,
-    references::{rename::RenameError, ReferenceSearchResult},
+    references::ReferenceSearchResult,
+    rename::RenameError,
     runnables::{Runnable, RunnableKind, TestId},
     syntax_highlighting::{
         tags::{Highlight, HlMod, HlMods, HlOperator, HlPunct, HlTag},
@@ -109,6 +109,7 @@ pub use ide_db::{
     symbol_index::Query,
     RootDatabase, SymbolKind,
 };
+pub use ide_diagnostics::{Diagnostic, DiagnosticsConfig, Severity};
 pub use ide_ssr::SsrError;
 pub use syntax::{TextRange, TextSize};
 pub use text_edit::{Indel, TextEdit};
@@ -537,7 +538,7 @@ impl Analysis {
     ) -> Cancellable<Vec<Assist>> {
         self.with_db(|db| {
             let ssr_assists = ssr::ssr_assists(db, &resolve, frange);
-            let mut acc = Assist::get(db, config, resolve, frange);
+            let mut acc = ide_assists::assists(db, config, resolve, frange);
             acc.extend(ssr_assists.into_iter());
             acc
         })
@@ -550,7 +551,7 @@ impl Analysis {
         resolve: AssistResolveStrategy,
         file_id: FileId,
     ) -> Cancellable<Vec<Diagnostic>> {
-        self.with_db(|db| diagnostics::diagnostics(db, config, &resolve, file_id))
+        self.with_db(|db| ide_diagnostics::diagnostics(db, config, &resolve, file_id))
     }
 
     /// Convenience function to return assists + quick fixes for diagnostics
@@ -567,9 +568,8 @@ impl Analysis {
         };
 
         self.with_db(|db| {
-            let ssr_assists = ssr::ssr_assists(db, &resolve, frange);
             let diagnostic_assists = if include_fixes {
-                diagnostics::diagnostics(db, diagnostics_config, &resolve, frange.file_id)
+                ide_diagnostics::diagnostics(db, diagnostics_config, &resolve, frange.file_id)
                     .into_iter()
                     .flat_map(|it| it.fixes.unwrap_or_default())
                     .filter(|it| it.target.intersect(frange.range).is_some())
@@ -577,10 +577,12 @@ impl Analysis {
             } else {
                 Vec::new()
             };
+            let ssr_assists = ssr::ssr_assists(db, &resolve, frange);
+            let assists = ide_assists::assists(db, assist_config, resolve, frange);
 
-            let mut res = Assist::get(db, assist_config, resolve, frange);
+            let mut res = diagnostic_assists;
             res.extend(ssr_assists.into_iter());
-            res.extend(diagnostic_assists.into_iter());
+            res.extend(assists.into_iter());
 
             res
         })
@@ -593,14 +595,14 @@ impl Analysis {
         position: FilePosition,
         new_name: &str,
     ) -> Cancellable<Result<SourceChange, RenameError>> {
-        self.with_db(|db| references::rename::rename(db, position, new_name))
+        self.with_db(|db| rename::rename(db, position, new_name))
     }
 
     pub fn prepare_rename(
         &self,
         position: FilePosition,
     ) -> Cancellable<Result<RangeInfo<()>, RenameError>> {
-        self.with_db(|db| references::rename::prepare_rename(db, position))
+        self.with_db(|db| rename::prepare_rename(db, position))
     }
 
     pub fn will_rename_file(
@@ -608,7 +610,7 @@ impl Analysis {
         file_id: FileId,
         new_name_stem: &str,
     ) -> Cancellable<Option<SourceChange>> {
-        self.with_db(|db| references::rename::will_rename_file(db, file_id, new_name_stem))
+        self.with_db(|db| rename::will_rename_file(db, file_id, new_name_stem))
     }
 
     pub fn structural_search_replace(
diff --git a/crates/ide/src/references.rs b/crates/ide/src/references.rs
index a0fdead2c..5808562a7 100644
--- a/crates/ide/src/references.rs
+++ b/crates/ide/src/references.rs
@@ -9,8 +9,6 @@
 //! at the index that the match starts at and its tree parent is
 //! resolved to the search element definition, we get a reference.
 
-pub(crate) mod rename;
-
 use hir::{PathResolution, Semantics};
 use ide_db::{
     base_db::FileId,
@@ -81,8 +79,7 @@ pub(crate) fn find_all_refs(
                 });
                 usages.references.retain(|_, it| !it.is_empty());
             }
-            Definition::ModuleDef(hir::ModuleDef::Adt(_))
-            | Definition::ModuleDef(hir::ModuleDef::Variant(_)) => {
+            Definition::ModuleDef(hir::ModuleDef::Adt(_) | hir::ModuleDef::Variant(_)) => {
                 refs.for_each(|it| {
                     it.retain(|reference| {
                         reference.name.as_name_ref().map_or(false, is_lit_name_ref)
diff --git a/crates/ide/src/references/rename.rs b/crates/ide/src/rename.rs
index 50cc1f963..96bd07708 100644
--- a/crates/ide/src/references/rename.rs
+++ b/crates/ide/src/rename.rs
@@ -1,45 +1,25 @@
-//! Renaming functionality
+//! Renaming functionality.
 //!
-//! All reference and file rename requests go through here where the corresponding [`SourceChange`]s
-//! will be calculated.
-use std::fmt::{self, Display};
-
-use either::Either;
-use hir::{AsAssocItem, InFile, Module, ModuleDef, ModuleSource, Semantics};
+//! This is mostly front-end for [`ide_db::rename`], but it also includes the
+//! tests. This module also implements a couple of magic tricks, like renaming
+//! `self` and to `self` (to switch between associated function and method).
+use hir::{AsAssocItem, InFile, Semantics};
 use ide_db::{
-    base_db::{AnchoredPathBuf, FileId},
+    base_db::FileId,
     defs::{Definition, NameClass, NameRefClass},
-    search::FileReference,
+    rename::{bail, format_err, source_edit_from_references, IdentifierKind},
     RootDatabase,
 };
-use stdx::never;
-use syntax::{
-    ast::{self, NameOwner},
-    lex_single_syntax_kind, AstNode, SyntaxKind, SyntaxNode, T,
-};
+use stdx::{always, never};
+use syntax::{ast, AstNode, SyntaxNode};
 
 use text_edit::TextEdit;
 
-use crate::{display::TryToNav, FilePosition, FileSystemEdit, RangeInfo, SourceChange, TextRange};
+use crate::{FilePosition, RangeInfo, SourceChange};
 
-type RenameResult<T> = Result<T, RenameError>;
-#[derive(Debug)]
-pub struct RenameError(String);
+pub use ide_db::rename::RenameError;
 
-impl fmt::Display for RenameError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        Display::fmt(&self.0, f)
-    }
-}
-
-macro_rules! format_err {
-    ($fmt:expr) => {RenameError(format!($fmt))};
-    ($fmt:expr, $($arg:tt)+) => {RenameError(format!($fmt, $($arg)+))}
-}
-
-macro_rules! bail {
-    ($($tokens:tt)*) => {return Err(format_err!($($tokens)*))}
-}
+type RenameResult<T> = Result<T, RenameError>;
 
 /// Prepares a rename. The sole job of this function is to return the TextRange of the thing that is
 /// being targeted for a rename.
@@ -51,27 +31,14 @@ pub(crate) fn prepare_rename(
     let source_file = sema.parse(position.file_id);
     let syntax = source_file.syntax();
 
-    let def = find_definition(&sema, syntax, position)?;
-    match def {
-        Definition::SelfType(_) => bail!("Cannot rename `Self`"),
-        Definition::ModuleDef(ModuleDef::BuiltinType(_)) => bail!("Cannot rename builtin type"),
-        Definition::ModuleDef(ModuleDef::Module(_)) => (),
-        _ => {
-            let nav = def
-                .try_to_nav(sema.db)
-                .ok_or_else(|| format_err!("No references found at position"))?;
-            nav.focus_range.ok_or_else(|| format_err!("No identifier available to rename"))?;
-        }
-    };
-    let name_like = sema
-        .find_node_at_offset_with_descend(syntax, position.offset)
-        .ok_or_else(|| format_err!("No references found at position"))?;
-    let node = match &name_like {
-        ast::NameLike::Name(it) => it.syntax(),
-        ast::NameLike::NameRef(it) => it.syntax(),
-        ast::NameLike::Lifetime(it) => it.syntax(),
-    };
-    Ok(RangeInfo::new(sema.original_range(node).range, ()))
+    let (name_like, def) = find_definition(&sema, syntax, position)?;
+    if def.range_for_rename(&sema).is_none() {
+        bail!("No references found at position")
+    }
+
+    let frange = sema.original_range(name_like.syntax());
+    always!(frange.range.contains_inclusive(position.offset) && frange.file_id == position.file_id);
+    Ok(RangeInfo::new(frange.range, ()))
 }
 
 // Feature: Rename
@@ -91,24 +58,23 @@ pub(crate) fn rename(
     new_name: &str,
 ) -> RenameResult<SourceChange> {
     let sema = Semantics::new(db);
-    rename_with_semantics(&sema, position, new_name)
-}
-
-pub(crate) fn rename_with_semantics(
-    sema: &Semantics<RootDatabase>,
-    position: FilePosition,
-    new_name: &str,
-) -> RenameResult<SourceChange> {
     let source_file = sema.parse(position.file_id);
     let syntax = source_file.syntax();
 
-    let def = find_definition(sema, syntax, position)?;
-    match def {
-        Definition::ModuleDef(ModuleDef::Module(module)) => rename_mod(sema, module, new_name),
-        Definition::SelfType(_) => bail!("Cannot rename `Self`"),
-        Definition::ModuleDef(ModuleDef::BuiltinType(_)) => bail!("Cannot rename builtin type"),
-        def => rename_reference(sema, def, new_name),
+    let (_name_like, def) = find_definition(&sema, syntax, position)?;
+
+    if let Definition::Local(local) = def {
+        if let Some(self_param) = local.as_self_param(sema.db) {
+            cov_mark::hit!(rename_self_to_param);
+            return rename_self_to_param(&sema, local, self_param, new_name);
+        }
+        if new_name == "self" {
+            cov_mark::hit!(rename_to_self);
+            return rename_to_self(&sema, local);
+        }
     }
+
+    def.rename(&sema, new_name)
 }
 
 /// Called by the client when it is about to rename a file.
@@ -119,47 +85,22 @@ pub(crate) fn will_rename_file(
 ) -> Option<SourceChange> {
     let sema = Semantics::new(db);
     let module = sema.to_module_def(file_id)?;
-    let mut change = rename_mod(&sema, module, new_name_stem).ok()?;
+    let def = Definition::ModuleDef(module.into());
+    let mut change = def.rename(&sema, new_name_stem).ok()?;
     change.file_system_edits.clear();
     Some(change)
 }
 
-#[derive(Copy, Clone, Debug, PartialEq)]
-enum IdentifierKind {
-    Ident,
-    Lifetime,
-    ToSelf,
-    Underscore,
-}
-
-fn check_identifier(new_name: &str) -> RenameResult<IdentifierKind> {
-    match lex_single_syntax_kind(new_name) {
-        Some(res) => match res {
-            (SyntaxKind::IDENT, _) => Ok(IdentifierKind::Ident),
-            (T![_], _) => Ok(IdentifierKind::Underscore),
-            (T![self], _) => Ok(IdentifierKind::ToSelf),
-            (SyntaxKind::LIFETIME_IDENT, _) if new_name != "'static" && new_name != "'_" => {
-                Ok(IdentifierKind::Lifetime)
-            }
-            (SyntaxKind::LIFETIME_IDENT, _) => {
-                bail!("Invalid name `{}`: not a lifetime identifier", new_name)
-            }
-            (_, Some(syntax_error)) => bail!("Invalid name `{}`: {}", new_name, syntax_error),
-            (_, None) => bail!("Invalid name `{}`: not an identifier", new_name),
-        },
-        None => bail!("Invalid name `{}`: not an identifier", new_name),
-    }
-}
-
 fn find_definition(
     sema: &Semantics<RootDatabase>,
     syntax: &SyntaxNode,
     position: FilePosition,
-) -> RenameResult<Definition> {
-    match sema
-        .find_node_at_offset_with_descend(syntax, position.offset)
-        .ok_or_else(|| format_err!("No references found at position"))?
-    {
+) -> RenameResult<(ast::NameLike, Definition)> {
+    let name_like = sema
+        .find_node_at_offset_with_descend::<ast::NameLike>(syntax, position.offset)
+        .ok_or_else(|| format_err!("No references found at position"))?;
+
+    let def = match &name_like {
         // renaming aliases would rename the item being aliased as the HIR doesn't track aliases yet
         ast::NameLike::Name(name)
             if name.syntax().parent().map_or(false, |it| ast::Rename::can_cast(it.kind())) =>
@@ -189,146 +130,9 @@ fn find_definition(
                     .map(|it| it.referenced_or_defined(sema.db))
             }),
     }
-    .ok_or_else(|| format_err!("No references found at position"))
-}
-
-fn rename_mod(
-    sema: &Semantics<RootDatabase>,
-    module: Module,
-    new_name: &str,
-) -> RenameResult<SourceChange> {
-    if IdentifierKind::Ident != check_identifier(new_name)? {
-        bail!("Invalid name `{0}`: cannot rename module to {0}", new_name);
-    }
-
-    let mut source_change = SourceChange::default();
-
-    let InFile { file_id, value: def_source } = module.definition_source(sema.db);
-    let file_id = file_id.original_file(sema.db);
-    if let ModuleSource::SourceFile(..) = def_source {
-        // mod is defined in path/to/dir/mod.rs
-        let path = if module.is_mod_rs(sema.db) {
-            format!("../{}/mod.rs", new_name)
-        } else {
-            format!("{}.rs", new_name)
-        };
-        let dst = AnchoredPathBuf { anchor: file_id, path };
-        let move_file = FileSystemEdit::MoveFile { src: file_id, dst };
-        source_change.push_file_system_edit(move_file);
-    }
-
-    if let Some(InFile { file_id, value: decl_source }) = module.declaration_source(sema.db) {
-        let file_id = file_id.original_file(sema.db);
-        match decl_source.name() {
-            Some(name) => source_change.insert_source_edit(
-                file_id,
-                TextEdit::replace(name.syntax().text_range(), new_name.to_string()),
-            ),
-            _ => never!("Module source node is missing a name"),
-        }
-    }
-    let def = Definition::ModuleDef(ModuleDef::Module(module));
-    let usages = def.usages(sema).all();
-    let ref_edits = usages.iter().map(|(&file_id, references)| {
-        (file_id, source_edit_from_references(references, def, new_name))
-    });
-    source_change.extend(ref_edits);
+    .ok_or_else(|| format_err!("No references found at position"))?;
 
-    Ok(source_change)
-}
-
-fn rename_reference(
-    sema: &Semantics<RootDatabase>,
-    mut def: Definition,
-    new_name: &str,
-) -> RenameResult<SourceChange> {
-    let ident_kind = check_identifier(new_name)?;
-
-    if matches!(
-        def, // is target a lifetime?
-        Definition::GenericParam(hir::GenericParam::LifetimeParam(_)) | Definition::Label(_)
-    ) {
-        match ident_kind {
-            IdentifierKind::Ident | IdentifierKind::ToSelf | IdentifierKind::Underscore => {
-                cov_mark::hit!(rename_not_a_lifetime_ident_ref);
-                bail!("Invalid name `{}`: not a lifetime identifier", new_name);
-            }
-            IdentifierKind::Lifetime => cov_mark::hit!(rename_lifetime),
-        }
-    } else {
-        match (ident_kind, def) {
-            (IdentifierKind::Lifetime, _) => {
-                cov_mark::hit!(rename_not_an_ident_ref);
-                bail!("Invalid name `{}`: not an identifier", new_name);
-            }
-            (IdentifierKind::ToSelf, Definition::Local(local)) => {
-                if local.is_self(sema.db) {
-                    // no-op
-                    cov_mark::hit!(rename_self_to_self);
-                    return Ok(SourceChange::default());
-                } else {
-                    cov_mark::hit!(rename_to_self);
-                    return rename_to_self(sema, local);
-                }
-            }
-            (ident_kind, Definition::Local(local)) => {
-                if let Some(self_param) = local.as_self_param(sema.db) {
-                    cov_mark::hit!(rename_self_to_param);
-                    return rename_self_to_param(sema, local, self_param, new_name, ident_kind);
-                } else {
-                    cov_mark::hit!(rename_local);
-                }
-            }
-            (IdentifierKind::ToSelf, _) => bail!("Invalid name `{}`: not an identifier", new_name),
-            (IdentifierKind::Ident, _) => cov_mark::hit!(rename_non_local),
-            (IdentifierKind::Underscore, _) => (),
-        }
-    }
-
-    def = match def {
-        // HACK: resolve trait impl items to the item def of the trait definition
-        // so that we properly resolve all trait item references
-        Definition::ModuleDef(mod_def) => mod_def
-            .as_assoc_item(sema.db)
-            .and_then(|it| it.containing_trait_impl(sema.db))
-            .and_then(|it| {
-                it.items(sema.db).into_iter().find_map(|it| match (it, mod_def) {
-                    (hir::AssocItem::Function(trait_func), ModuleDef::Function(func))
-                        if trait_func.name(sema.db) == func.name(sema.db) =>
-                    {
-                        Some(Definition::ModuleDef(ModuleDef::Function(trait_func)))
-                    }
-                    (hir::AssocItem::Const(trait_konst), ModuleDef::Const(konst))
-                        if trait_konst.name(sema.db) == konst.name(sema.db) =>
-                    {
-                        Some(Definition::ModuleDef(ModuleDef::Const(trait_konst)))
-                    }
-                    (
-                        hir::AssocItem::TypeAlias(trait_type_alias),
-                        ModuleDef::TypeAlias(type_alias),
-                    ) if trait_type_alias.name(sema.db) == type_alias.name(sema.db) => {
-                        Some(Definition::ModuleDef(ModuleDef::TypeAlias(trait_type_alias)))
-                    }
-                    _ => None,
-                })
-            })
-            .unwrap_or(def),
-        _ => def,
-    };
-    let usages = def.usages(sema).all();
-
-    if !usages.is_empty() && ident_kind == IdentifierKind::Underscore {
-        cov_mark::hit!(rename_underscore_multiple);
-        bail!("Cannot rename reference to `_` as it is being referenced multiple times");
-    }
-    let mut source_change = SourceChange::default();
-    source_change.extend(usages.iter().map(|(&file_id, references)| {
-        (file_id, source_edit_from_references(references, def, new_name))
-    }));
-
-    let (file_id, edit) = source_edit_from_def(sema, def, new_name)?;
-    source_change.insert_source_edit(file_id, edit);
-    Ok(source_change)
+    Ok((name_like, def))
 }
 
 fn rename_to_self(sema: &Semantics<RootDatabase>, local: hir::Local) -> RenameResult<SourceChange> {
@@ -398,8 +202,15 @@ fn rename_self_to_param(
     local: hir::Local,
     self_param: hir::SelfParam,
     new_name: &str,
-    identifier_kind: IdentifierKind,
 ) -> RenameResult<SourceChange> {
+    if new_name == "self" {
+        // Let's do nothing rather than complain.
+        cov_mark::hit!(rename_self_to_self);
+        return Ok(SourceChange::default());
+    }
+
+    let identifier_kind = IdentifierKind::classify(new_name)?;
+
     let InFile { file_id, value: self_param } =
         self_param.source(sema.db).ok_or_else(|| format_err!("cannot find function source"))?;
 
@@ -441,150 +252,6 @@ fn text_edit_from_self_param(self_param: &ast::SelfParam, new_name: &str) -> Opt
     Some(TextEdit::replace(self_param.syntax().text_range(), replacement_text))
 }
 
-fn source_edit_from_references(
-    references: &[FileReference],
-    def: Definition,
-    new_name: &str,
-) -> TextEdit {
-    let mut edit = TextEdit::builder();
-    for reference in references {
-        let (range, replacement) = match &reference.name {
-            // if the ranges differ then the node is inside a macro call, we can't really attempt
-            // to make special rewrites like shorthand syntax and such, so just rename the node in
-            // the macro input
-            ast::NameLike::NameRef(name_ref)
-                if name_ref.syntax().text_range() == reference.range =>
-            {
-                source_edit_from_name_ref(name_ref, new_name, def)
-            }
-            ast::NameLike::Name(name) if name.syntax().text_range() == reference.range => {
-                source_edit_from_name(name, new_name)
-            }
-            _ => None,
-        }
-        .unwrap_or_else(|| (reference.range, new_name.to_string()));
-        edit.replace(range, replacement);
-    }
-    edit.finish()
-}
-
-fn source_edit_from_name(name: &ast::Name, new_name: &str) -> Option<(TextRange, String)> {
-    if let Some(_) = ast::RecordPatField::for_field_name(name) {
-        if let Some(ident_pat) = name.syntax().parent().and_then(ast::IdentPat::cast) {
-            return Some((
-                TextRange::empty(ident_pat.syntax().text_range().start()),
-                [new_name, ": "].concat(),
-            ));
-        }
-    }
-    None
-}
-
-fn source_edit_from_name_ref(
-    name_ref: &ast::NameRef,
-    new_name: &str,
-    def: Definition,
-) -> Option<(TextRange, String)> {
-    if let Some(record_field) = ast::RecordExprField::for_name_ref(name_ref) {
-        let rcf_name_ref = record_field.name_ref();
-        let rcf_expr = record_field.expr();
-        match (rcf_name_ref, rcf_expr.and_then(|it| it.name_ref())) {
-            // field: init-expr, check if we can use a field init shorthand
-            (Some(field_name), Some(init)) => {
-                if field_name == *name_ref {
-                    if init.text() == new_name {
-                        cov_mark::hit!(test_rename_field_put_init_shorthand);
-                        // same names, we can use a shorthand here instead.
-                        // we do not want to erase attributes hence this range start
-                        let s = field_name.syntax().text_range().start();
-                        let e = record_field.syntax().text_range().end();
-                        return Some((TextRange::new(s, e), new_name.to_owned()));
-                    }
-                } else if init == *name_ref {
-                    if field_name.text() == new_name {
-                        cov_mark::hit!(test_rename_local_put_init_shorthand);
-                        // same names, we can use a shorthand here instead.
-                        // we do not want to erase attributes hence this range start
-                        let s = field_name.syntax().text_range().start();
-                        let e = record_field.syntax().text_range().end();
-                        return Some((TextRange::new(s, e), new_name.to_owned()));
-                    }
-                }
-                None
-            }
-            // init shorthand
-            // FIXME: instead of splitting the shorthand, recursively trigger a rename of the
-            // other name https://github.com/rust-analyzer/rust-analyzer/issues/6547
-            (None, Some(_)) if matches!(def, Definition::Field(_)) => {
-                cov_mark::hit!(test_rename_field_in_field_shorthand);
-                let s = name_ref.syntax().text_range().start();
-                Some((TextRange::empty(s), format!("{}: ", new_name)))
-            }
-            (None, Some(_)) if matches!(def, Definition::Local(_)) => {
-                cov_mark::hit!(test_rename_local_in_field_shorthand);
-                let s = name_ref.syntax().text_range().end();
-                Some((TextRange::empty(s), format!(": {}", new_name)))
-            }
-            _ => None,
-        }
-    } else if let Some(record_field) = ast::RecordPatField::for_field_name_ref(name_ref) {
-        let rcf_name_ref = record_field.name_ref();
-        let rcf_pat = record_field.pat();
-        match (rcf_name_ref, rcf_pat) {
-            // field: rename
-            (Some(field_name), Some(ast::Pat::IdentPat(pat))) if field_name == *name_ref => {
-                // field name is being renamed
-                if pat.name().map_or(false, |it| it.text() == new_name) {
-                    cov_mark::hit!(test_rename_field_put_init_shorthand_pat);
-                    // same names, we can use a shorthand here instead/
-                    // we do not want to erase attributes hence this range start
-                    let s = field_name.syntax().text_range().start();
-                    let e = record_field.syntax().text_range().end();
-                    Some((TextRange::new(s, e), pat.to_string()))
-                } else {
-                    None
-                }
-            }
-            _ => None,
-        }
-    } else {
-        None
-    }
-}
-
-fn source_edit_from_def(
-    sema: &Semantics<RootDatabase>,
-    def: Definition,
-    new_name: &str,
-) -> RenameResult<(FileId, TextEdit)> {
-    let nav =
-        def.try_to_nav(sema.db).ok_or_else(|| format_err!("No references found at position"))?;
-
-    let mut replacement_text = String::new();
-    let mut repl_range =
-        nav.focus_range.ok_or_else(|| format_err!("No identifier available to rename"))?;
-    if let Definition::Local(local) = def {
-        if let Either::Left(pat) = local.source(sema.db).value {
-            if matches!(
-                pat.syntax().parent().and_then(ast::RecordPatField::cast),
-                Some(pat_field) if pat_field.name_ref().is_none()
-            ) {
-                replacement_text.push_str(": ");
-                replacement_text.push_str(new_name);
-                repl_range = TextRange::new(
-                    pat.syntax().text_range().end(),
-                    pat.syntax().text_range().end(),
-                );
-            }
-        }
-    }
-    if replacement_text.is_empty() {
-        replacement_text.push_str(new_name);
-    }
-    let edit = TextEdit::replace(repl_range, replacement_text);
-    Ok((nav.file_id, edit))
-}
-
 #[cfg(test)]
 mod tests {
     use expect_test::{expect, Expect};
@@ -691,7 +358,7 @@ fn baz() {
     x.0$0 = 5;
 }
 "#,
-            expect![[r#"No identifier available to rename"#]],
+            expect![[r#"No references found at position"#]],
         );
     }
 
@@ -703,7 +370,7 @@ fn foo() {
     let x: i32$0 = 0;
 }
 "#,
-            expect![[r#"Cannot rename builtin type"#]],
+            expect![[r#"No references found at position"#]],
         );
     }
 
@@ -719,7 +386,7 @@ impl Foo {
     }
 }
 "#,
-            expect![[r#"Cannot rename `Self`"#]],
+            expect![[r#"No references found at position"#]],
         );
     }
 
@@ -801,7 +468,6 @@ impl Foo {
 
     #[test]
     fn test_rename_for_local() {
-        cov_mark::check!(rename_local);
         check(
             "k",
             r#"
@@ -2101,4 +1767,22 @@ fn f() { <()>::BAR$0; }"#,
             res,
         );
     }
+
+    #[test]
+    fn macros_are_broken_lol() {
+        cov_mark::check!(macros_are_broken_lol);
+        check(
+            "lol",
+            r#"
+macro_rules! m { () => { fn f() {} } }
+m!();
+fn main() { f$0()  }
+"#,
+            r#"
+macro_rules! m { () => { fn f() {} } }
+lol
+fn main() { lol()  }
+"#,
+        )
+    }
 }
diff --git a/crates/ide/src/syntax_highlighting.rs b/crates/ide/src/syntax_highlighting.rs
index e186b82b7..d44a1b45f 100644
--- a/crates/ide/src/syntax_highlighting.rs
+++ b/crates/ide/src/syntax_highlighting.rs
@@ -294,7 +294,7 @@ fn traverse(
                 Some(parent) => {
                     // We only care Name and Name_ref
                     match (token.kind(), parent.kind()) {
-                        (IDENT, NAME) | (IDENT, NAME_REF) => parent.into(),
+                        (IDENT, NAME | NAME_REF) => parent.into(),
                         _ => token.into(),
                     }
                 }
@@ -310,7 +310,7 @@ fn traverse(
                 Some(parent) => {
                     // We only care Name and Name_ref
                     match (token.kind(), parent.kind()) {
-                        (IDENT, NAME) | (IDENT, NAME_REF) => parent.into(),
+                        (IDENT, NAME | NAME_REF) => parent.into(),
                         _ => token.into(),
                     }
                 }
diff --git a/crates/ide/src/syntax_highlighting/highlight.rs b/crates/ide/src/syntax_highlighting/highlight.rs
index 7a53268e8..6834fe11a 100644
--- a/crates/ide/src/syntax_highlighting/highlight.rs
+++ b/crates/ide/src/syntax_highlighting/highlight.rs
@@ -48,7 +48,13 @@ pub(super) fn element(
             match name_kind {
                 Some(NameClass::ExternCrate(_)) => SymbolKind::Module.into(),
                 Some(NameClass::Definition(def)) => {
-                    highlight_def(db, krate, def) | HlMod::Definition
+                    let mut h = highlight_def(db, krate, def) | HlMod::Definition;
+                    if let Definition::ModuleDef(hir::ModuleDef::Trait(trait_)) = &def {
+                        if trait_.is_unsafe(db) {
+                            h |= HlMod::Unsafe;
+                        }
+                    }
+                    h
                 }
                 Some(NameClass::ConstReference(def)) => highlight_def(db, krate, def),
                 Some(NameClass::PatFieldShorthand { field_ref, .. }) => {
@@ -87,20 +93,34 @@ pub(super) fn element(
 
                             let mut h = highlight_def(db, krate, def);
 
-                            if let Definition::Local(local) = &def {
-                                if is_consumed_lvalue(name_ref.syntax().clone().into(), local, db) {
+                            match def {
+                                Definition::Local(local)
+                                    if is_consumed_lvalue(
+                                        name_ref.syntax().clone().into(),
+                                        &local,
+                                        db,
+                                    ) =>
+                                {
                                     h |= HlMod::Consuming;
                                 }
-                            }
-
-                            if let Some(parent) = name_ref.syntax().parent() {
-                                if matches!(parent.kind(), FIELD_EXPR | RECORD_PAT_FIELD) {
-                                    if let Definition::Field(field) = def {
-                                        if let hir::VariantDef::Union(_) = field.parent_def(db) {
-                                            h |= HlMod::Unsafe;
+                                Definition::ModuleDef(hir::ModuleDef::Trait(trait_))
+                                    if trait_.is_unsafe(db) =>
+                                {
+                                    if ast::Impl::for_trait_name_ref(&name_ref).is_some() {
+                                        h |= HlMod::Unsafe;
+                                    }
+                                }
+                                Definition::Field(field) => {
+                                    if let Some(parent) = name_ref.syntax().parent() {
+                                        if matches!(parent.kind(), FIELD_EXPR | RECORD_PAT_FIELD) {
+                                            if let hir::VariantDef::Union(_) = field.parent_def(db)
+                                            {
+                                                h |= HlMod::Unsafe;
+                                            }
                                         }
                                     }
                                 }
+                                _ => (),
                             }
 
                             h
@@ -354,15 +374,7 @@ fn highlight_def(db: &RootDatabase, krate: Option<hir::Crate>, def: Definition)
 
                 h
             }
-            hir::ModuleDef::Trait(trait_) => {
-                let mut h = Highlight::new(HlTag::Symbol(SymbolKind::Trait));
-
-                if trait_.is_unsafe(db) {
-                    h |= HlMod::Unsafe;
-                }
-
-                h
-            }
+            hir::ModuleDef::Trait(_) => Highlight::new(HlTag::Symbol(SymbolKind::Trait)),
             hir::ModuleDef::TypeAlias(type_) => {
                 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::TypeAlias));
 
diff --git a/crates/ide/src/syntax_highlighting/html.rs b/crates/ide/src/syntax_highlighting/html.rs
index 478facfee..21376a7ae 100644
--- a/crates/ide/src/syntax_highlighting/html.rs
+++ b/crates/ide/src/syntax_highlighting/html.rs
@@ -67,6 +67,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .field              { color: #94BFF3; }
 .function           { color: #93E0E3; }
 .function.unsafe    { color: #BC8383; }
+.trait.unsafe       { color: #BC8383; }
 .operator.unsafe    { color: #BC8383; }
 .parameter          { color: #94BFF3; }
 .text               { color: #DCDCCC; }
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_assoc_functions.html b/crates/ide/src/syntax_highlighting/test_data/highlight_assoc_functions.html
index a0ea1db34..4e85f7c0b 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_assoc_functions.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_assoc_functions.html
@@ -15,6 +15,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .field              { color: #94BFF3; }
 .function           { color: #93E0E3; }
 .function.unsafe    { color: #BC8383; }
+.trait.unsafe       { color: #BC8383; }
 .operator.unsafe    { color: #BC8383; }
 .parameter          { color: #94BFF3; }
 .text               { color: #DCDCCC; }
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html b/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html
index 921a956e6..79a285107 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html
@@ -15,6 +15,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .field              { color: #94BFF3; }
 .function           { color: #93E0E3; }
 .function.unsafe    { color: #BC8383; }
+.trait.unsafe       { color: #BC8383; }
 .operator.unsafe    { color: #BC8383; }
 .parameter          { color: #94BFF3; }
 .text               { color: #DCDCCC; }
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_extern_crate.html b/crates/ide/src/syntax_highlighting/test_data/highlight_extern_crate.html
index ca9bb1e7d..13f589cc0 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_extern_crate.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_extern_crate.html
@@ -15,6 +15,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .field              { color: #94BFF3; }
 .function           { color: #93E0E3; }
 .function.unsafe    { color: #BC8383; }
+.trait.unsafe       { color: #BC8383; }
 .operator.unsafe    { color: #BC8383; }
 .parameter          { color: #94BFF3; }
 .text               { color: #DCDCCC; }
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_injection.html b/crates/ide/src/syntax_highlighting/test_data/highlight_injection.html
index 6202a03ce..50df376ae 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_injection.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_injection.html
@@ -15,6 +15,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .field              { color: #94BFF3; }
 .function           { color: #93E0E3; }
 .function.unsafe    { color: #BC8383; }
+.trait.unsafe       { color: #BC8383; }
 .operator.unsafe    { color: #BC8383; }
 .parameter          { color: #94BFF3; }
 .text               { color: #DCDCCC; }
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_strings.html b/crates/ide/src/syntax_highlighting/test_data/highlight_strings.html
index e860d713e..96cb09642 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_strings.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_strings.html
@@ -15,6 +15,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .field              { color: #94BFF3; }
 .function           { color: #93E0E3; }
 .function.unsafe    { color: #BC8383; }
+.trait.unsafe       { color: #BC8383; }
 .operator.unsafe    { color: #BC8383; }
 .parameter          { color: #94BFF3; }
 .text               { color: #DCDCCC; }
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_unsafe.html b/crates/ide/src/syntax_highlighting/test_data/highlight_unsafe.html
index 68165bdbf..55453468b 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_unsafe.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_unsafe.html
@@ -15,6 +15,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .field              { color: #94BFF3; }
 .function           { color: #93E0E3; }
 .function.unsafe    { color: #BC8383; }
+.trait.unsafe       { color: #BC8383; }
 .operator.unsafe    { color: #BC8383; }
 .parameter          { color: #94BFF3; }
 .text               { color: #DCDCCC; }
@@ -61,6 +62,11 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
     <span class="field declaration">a</span><span class="colon">:</span> <span class="builtin_type">u16</span><span class="comma">,</span>
 <span class="brace">}</span>
 
+<span class="keyword unsafe">unsafe</span> <span class="keyword">trait</span> <span class="trait declaration unsafe">UnsafeTrait</span> <span class="brace">{</span><span class="brace">}</span>
+<span class="keyword unsafe">unsafe</span> <span class="keyword">impl</span> <span class="trait unsafe">UnsafeTrait</span> <span class="keyword">for</span> <span class="struct">Packed</span> <span class="brace">{</span><span class="brace">}</span>
+
+<span class="keyword">fn</span> <span class="function declaration">require_unsafe_trait</span><span class="angle">&lt;</span><span class="type_param declaration">T</span><span class="colon">:</span> <span class="trait">UnsafeTrait</span><span class="angle">&gt;</span><span class="parenthesis">(</span><span class="punctuation">_</span><span class="colon">:</span> <span class="type_param">T</span><span class="parenthesis">)</span> <span class="brace">{</span><span class="brace">}</span>
+
 <span class="keyword">trait</span> <span class="trait declaration">DoTheAutoref</span> <span class="brace">{</span>
     <span class="keyword">fn</span> <span class="function associated declaration trait">calls_autoref</span><span class="parenthesis">(</span><span class="operator">&</span><span class="self_keyword declaration">self</span><span class="parenthesis">)</span><span class="semicolon">;</span>
 <span class="brace">}</span>
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlighting.html b/crates/ide/src/syntax_highlighting/test_data/highlighting.html
index 59f1e8e4c..9232cf905 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlighting.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlighting.html
@@ -15,6 +15,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .field              { color: #94BFF3; }
 .function           { color: #93E0E3; }
 .function.unsafe    { color: #BC8383; }
+.trait.unsafe       { color: #BC8383; }
 .operator.unsafe    { color: #BC8383; }
 .parameter          { color: #94BFF3; }
 .text               { color: #DCDCCC; }
diff --git a/crates/ide/src/syntax_highlighting/test_data/injection.html b/crates/ide/src/syntax_highlighting/test_data/injection.html
index 9ab46d05c..082837328 100644
--- a/crates/ide/src/syntax_highlighting/test_data/injection.html
+++ b/crates/ide/src/syntax_highlighting/test_data/injection.html
@@ -15,6 +15,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .field              { color: #94BFF3; }
 .function           { color: #93E0E3; }
 .function.unsafe    { color: #BC8383; }
+.trait.unsafe       { color: #BC8383; }
 .operator.unsafe    { color: #BC8383; }
 .parameter          { color: #94BFF3; }
 .text               { color: #DCDCCC; }
diff --git a/crates/ide/src/syntax_highlighting/test_data/rainbow_highlighting.html b/crates/ide/src/syntax_highlighting/test_data/rainbow_highlighting.html
index 666b0b228..763917714 100644
--- a/crates/ide/src/syntax_highlighting/test_data/rainbow_highlighting.html
+++ b/crates/ide/src/syntax_highlighting/test_data/rainbow_highlighting.html
@@ -15,6 +15,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .field              { color: #94BFF3; }
 .function           { color: #93E0E3; }
 .function.unsafe    { color: #BC8383; }
+.trait.unsafe       { color: #BC8383; }
 .operator.unsafe    { color: #BC8383; }
 .parameter          { color: #94BFF3; }
 .text               { color: #DCDCCC; }
diff --git a/crates/ide/src/syntax_highlighting/tests.rs b/crates/ide/src/syntax_highlighting/tests.rs
index f7d8334a0..4f0b1ce85 100644
--- a/crates/ide/src/syntax_highlighting/tests.rs
+++ b/crates/ide/src/syntax_highlighting/tests.rs
@@ -527,6 +527,11 @@ struct Packed {
     a: u16,
 }
 
+unsafe trait UnsafeTrait {}
+unsafe impl UnsafeTrait for Packed {}
+
+fn require_unsafe_trait<T: UnsafeTrait>(_: T) {}
+
 trait DoTheAutoref {
     fn calls_autoref(&self);
 }
diff --git a/crates/ide/src/typing.rs b/crates/ide/src/typing.rs
index 4ad49eca0..37ae92350 100644
--- a/crates/ide/src/typing.rs
+++ b/crates/ide/src/typing.rs
@@ -23,7 +23,7 @@ use syntax::{
     algo::find_node_at_offset,
     ast::{self, edit::IndentLevel, AstToken},
     AstNode, Parse, SourceFile,
-    SyntaxKind::{FIELD_EXPR, METHOD_CALL_EXPR},
+    SyntaxKind::{self, FIELD_EXPR, METHOD_CALL_EXPR},
     TextRange, TextSize,
 };
 
@@ -95,9 +95,16 @@ fn on_opening_brace_typed(file: &Parse<SourceFile>, offset: TextSize) -> Option<
     }
 
     let brace_token = file.tree().syntax().token_at_offset(offset).right_biased()?;
+    if brace_token.kind() != SyntaxKind::L_CURLY {
+        return None;
+    }
 
-    // Remove the `{` to get a better parse tree, and reparse
-    let file = file.reparse(&Indel::delete(brace_token.text_range()));
+    // Remove the `{` to get a better parse tree, and reparse.
+    let range = brace_token.text_range();
+    if !stdx::always!(range.len() == TextSize::of('{')) {
+        return None;
+    }
+    let file = file.reparse(&Indel::delete(range));
 
     if let Some(edit) = brace_expr(&file.tree(), offset) {
         return Some(edit);
@@ -550,6 +557,29 @@ fn f() {
     }
 
     #[test]
+    fn noop_in_string_literal() {
+        // Regression test for #9351
+        type_char_noop(
+            '{',
+            r##"
+fn check_with(ra_fixture: &str, expect: Expect) {
+    let base = r#"
+enum E { T(), R$0, C }
+use self::E::X;
+const Z: E = E::C;
+mod m {}
+asdasdasdasdasdasda
+sdasdasdasdasdasda
+sdasdasdasdasd
+"#;
+    let actual = completion_list(&format!("{}\n{}", base, ra_fixture));
+    expect.assert_eq(&actual)
+}
+            "##,
+        );
+    }
+
+    #[test]
     fn adds_closing_brace_for_use_tree() {
         type_char(
             '{',
diff --git a/crates/ide_assists/src/handlers/apply_demorgan.rs b/crates/ide_assists/src/handlers/apply_demorgan.rs
index c93959e66..e2bd6e456 100644
--- a/crates/ide_assists/src/handlers/apply_demorgan.rs
+++ b/crates/ide_assists/src/handlers/apply_demorgan.rs
@@ -147,74 +147,92 @@ fn opposite_logic_op(kind: ast::BinOp) -> Option<&'static str> {
 
 #[cfg(test)]
 mod tests {
-    use ide_db::helpers::FamousDefs;
-
-    use super::*;
-
     use crate::tests::{check_assist, check_assist_not_applicable};
 
-    const ORDABLE_FIXTURE: &'static str = r"
-//- /lib.rs deps:core crate:ordable
-struct NonOrderable;
-struct Orderable;
-impl core::cmp::Ord for Orderable {}
-";
-
-    fn check(ra_fixture_before: &str, ra_fixture_after: &str) {
-        let before = &format!(
-            "//- /main.rs crate:main deps:core,ordable\n{}\n{}{}",
-            ra_fixture_before,
-            FamousDefs::FIXTURE,
-            ORDABLE_FIXTURE
-        );
-        check_assist(apply_demorgan, before, &format!("{}\n", ra_fixture_after));
-    }
+    use super::*;
 
     #[test]
     fn demorgan_handles_leq() {
-        check(
-            r"use ordable::Orderable;
+        check_assist(
+            apply_demorgan,
+            r#"
+//- minicore: ord, derive
+#[derive(PartialEq, Eq, PartialOrd, Ord)]
+struct S;
+
 fn f() {
-    Orderable < Orderable &&$0 Orderable <= Orderable
-}",
-            r"use ordable::Orderable;
+    S < S &&$0 S <= S
+}
+"#,
+            r#"
+#[derive(PartialEq, Eq, PartialOrd, Ord)]
+struct S;
+
 fn f() {
-    !(Orderable >= Orderable || Orderable > Orderable)
-}",
+    !(S >= S || S > S)
+}
+"#,
         );
-        check(
-            r"use ordable::NonOrderable;
+
+        check_assist(
+            apply_demorgan,
+            r#"
+//- minicore: ord, derive
+struct S;
+
 fn f() {
-    NonOrderable < NonOrderable &&$0 NonOrderable <= NonOrderable
-}",
-            r"use ordable::NonOrderable;
+    S < S &&$0 S <= S
+}
+"#,
+            r#"
+struct S;
+
 fn f() {
-    !(!(NonOrderable < NonOrderable) || !(NonOrderable <= NonOrderable))
-}",
+    !(!(S < S) || !(S <= S))
+}
+"#,
         );
     }
 
     #[test]
     fn demorgan_handles_geq() {
-        check(
-            r"use ordable::Orderable;
+        check_assist(
+            apply_demorgan,
+            r#"
+//- minicore: ord, derive
+#[derive(PartialEq, Eq, PartialOrd, Ord)]
+struct S;
+
 fn f() {
-    Orderable > Orderable &&$0 Orderable >= Orderable
-}",
-            r"use ordable::Orderable;
+    S > S &&$0 S >= S
+}
+"#,
+            r#"
+#[derive(PartialEq, Eq, PartialOrd, Ord)]
+struct S;
+
 fn f() {
-    !(Orderable <= Orderable || Orderable < Orderable)
-}",
+    !(S <= S || S < S)
+}
+"#,
         );
-        check(
-            r"use ordable::NonOrderable;
+        check_assist(
+            apply_demorgan,
+            r#"
+//- minicore: ord, derive
+struct S;
+
 fn f() {
-    Orderable > Orderable &&$0 Orderable >= Orderable
-}",
-            r"use ordable::NonOrderable;
+    S > S &&$0 S >= S
+}
+"#,
+            r#"
+struct S;
+
 fn f() {
-    !(!(Orderable > Orderable) || !(Orderable >= Orderable))
-}",
+    !(!(S > S) || !(S >= S))
+}
+"#,
         );
     }
 
diff --git a/crates/ide_assists/src/handlers/auto_import.rs b/crates/ide_assists/src/handlers/auto_import.rs
index d4748ef3a..accc345fc 100644
--- a/crates/ide_assists/src/handlers/auto_import.rs
+++ b/crates/ide_assists/src/handlers/auto_import.rs
@@ -103,8 +103,9 @@ pub(crate) fn auto_import(acc: &mut Assists, ctx: &AssistContext) -> Option<()>
                 let scope = match scope.clone() {
                     ImportScope::File(it) => ImportScope::File(builder.make_mut(it)),
                     ImportScope::Module(it) => ImportScope::Module(builder.make_mut(it)),
+                    ImportScope::Block(it) => ImportScope::Block(builder.make_mut(it)),
                 };
-                insert_use(&scope, mod_path_to_ast(&import.import_path), ctx.config.insert_use);
+                insert_use(&scope, mod_path_to_ast(&import.import_path), &ctx.config.insert_use);
             },
         );
     }
diff --git a/crates/ide_assists/src/handlers/convert_into_to_from.rs b/crates/ide_assists/src/handlers/convert_into_to_from.rs
index 199e1ad5c..2d8b936cd 100644
--- a/crates/ide_assists/src/handlers/convert_into_to_from.rs
+++ b/crates/ide_assists/src/handlers/convert_into_to_from.rs
@@ -6,15 +6,14 @@ use syntax::ast::{self, AstNode, NameOwner};
 
 use crate::{AssistContext, AssistId, AssistKind, Assists};
 
+// FIXME: this should be a diagnostic
+
 // Assist: convert_into_to_from
 //
 // Converts an Into impl to an equivalent From impl.
 //
 // ```
-// # //- /lib.rs crate:core
-// # pub mod convert { pub trait Into<T> { pub fn into(self) -> T; } }
-// # //- /lib.rs crate:main deps:core
-// # use core::convert::Into;
+// # //- minicore: from
 // impl $0Into<Thing> for usize {
 //     fn into(self) -> Thing {
 //         Thing {
@@ -26,7 +25,6 @@ use crate::{AssistContext, AssistId, AssistKind, Assists};
 // ```
 // ->
 // ```
-// # use core::convert::Into;
 // impl From<usize> for Thing {
 //     fn from(val: usize) -> Self {
 //         Thing {
@@ -114,12 +112,14 @@ pub(crate) fn convert_into_to_from(acc: &mut Assists, ctx: &AssistContext) -> Op
 mod tests {
     use super::*;
 
-    use crate::tests::check_assist;
+    use crate::tests::{check_assist, check_assist_not_applicable};
 
     #[test]
     fn convert_into_to_from_converts_a_struct() {
-        check_convert_into_to_from(
+        check_assist(
+            convert_into_to_from,
             r#"
+//- minicore: from
 struct Thing {
     a: String,
     b: usize
@@ -154,8 +154,10 @@ impl From<usize> for Thing {
 
     #[test]
     fn convert_into_to_from_converts_enums() {
-        check_convert_into_to_from(
+        check_assist(
+            convert_into_to_from,
             r#"
+//- minicore: from
 enum Thing {
     Foo(String),
     Bar(String)
@@ -190,8 +192,10 @@ impl From<Thing> for String {
 
     #[test]
     fn convert_into_to_from_on_enum_with_lifetimes() {
-        check_convert_into_to_from(
+        check_assist(
+            convert_into_to_from,
             r#"
+//- minicore: from
 enum Thing<'a> {
     Foo(&'a str),
     Bar(&'a str)
@@ -226,8 +230,10 @@ impl<'a> From<Thing<'a>> for &'a str {
 
     #[test]
     fn convert_into_to_from_works_on_references() {
-        check_convert_into_to_from(
+        check_assist(
+            convert_into_to_from,
             r#"
+//- minicore: from
 struct Thing(String);
 
 impl $0core::convert::Into<String> for &Thing {
@@ -250,8 +256,10 @@ impl From<&Thing> for String {
 
     #[test]
     fn convert_into_to_from_works_on_qualified_structs() {
-        check_convert_into_to_from(
+        check_assist(
+            convert_into_to_from,
             r#"
+//- minicore: from
 mod things {
     pub struct Thing(String);
     pub struct BetterThing(String);
@@ -280,8 +288,10 @@ impl From<&things::Thing> for things::BetterThing {
 
     #[test]
     fn convert_into_to_from_works_on_qualified_enums() {
-        check_convert_into_to_from(
+        check_assist(
+            convert_into_to_from,
             r#"
+//- minicore: from
 mod things {
     pub enum Thing {
         A(String)
@@ -323,10 +333,12 @@ impl From<&things::Thing> for things::BetterThing {
     #[test]
     fn convert_into_to_from_not_applicable_on_any_trait_named_into() {
         check_assist_not_applicable(
+            convert_into_to_from,
             r#"
-pub trait Into<T> {{
+//- minicore: from
+pub trait Into<T> {
     pub fn into(self) -> T;
-}}
+}
 
 struct Thing {
     a: String,
@@ -342,14 +354,4 @@ impl $0Into<Thing> for String {
 "#,
         );
     }
-
-    fn check_convert_into_to_from(before: &str, after: &str) {
-        let before = &format!("//- /main.rs crate:main deps:core{}{}", before, FamousDefs::FIXTURE);
-        check_assist(convert_into_to_from, before, after);
-    }
-
-    fn check_assist_not_applicable(before: &str) {
-        let before = &format!("//- /main.rs crate:main deps:core{}{}", before, FamousDefs::FIXTURE);
-        crate::tests::check_assist_not_applicable(convert_into_to_from, before);
-    }
 }
diff --git a/crates/ide_assists/src/handlers/convert_iter_for_each_to_for.rs b/crates/ide_assists/src/handlers/convert_iter_for_each_to_for.rs
index 4e75a7b14..70754adf9 100644
--- a/crates/ide_assists/src/handlers/convert_iter_for_each_to_for.rs
+++ b/crates/ide_assists/src/handlers/convert_iter_for_each_to_for.rs
@@ -11,14 +11,10 @@ use crate::{AssistContext, AssistId, AssistKind, Assists};
 // Converts an Iterator::for_each function into a for loop.
 //
 // ```
-// # //- /lib.rs crate:core
-// # pub mod iter { pub mod traits { pub mod iterator { pub trait Iterator {} } } }
-// # pub struct SomeIter;
-// # impl self::iter::traits::iterator::Iterator for SomeIter {}
-// # //- /lib.rs crate:main deps:core
-// # use core::SomeIter;
+// # //- minicore: iterators
+// # use core::iter;
 // fn main() {
-//     let iter = SomeIter;
+//     let iter = iter::repeat((9, 2));
 //     iter.for_each$0(|(x, y)| {
 //         println!("x: {}, y: {}", x, y);
 //     });
@@ -26,9 +22,9 @@ use crate::{AssistContext, AssistId, AssistKind, Assists};
 // ```
 // ->
 // ```
-// # use core::SomeIter;
+// # use core::iter;
 // fn main() {
-//     let iter = SomeIter;
+//     let iter = iter::repeat((9, 2));
 //     for (x, y) in iter {
 //         println!("x: {}, y: {}", x, y);
 //     }
@@ -77,9 +73,11 @@ fn validate_method_call_expr(
     expr: ast::MethodCallExpr,
 ) -> Option<(ast::Expr, ast::Expr)> {
     let name_ref = expr.name_ref()?;
-    if name_ref.syntax().text_range().intersect(ctx.frange.range).is_none()
-        || name_ref.text() != "for_each"
-    {
+    if name_ref.syntax().text_range().intersect(ctx.frange.range).is_none() {
+        cov_mark::hit!(test_for_each_not_applicable_invalid_cursor_pos);
+        return None;
+    }
+    if name_ref.text() != "for_each" {
         return None;
     }
 
@@ -98,59 +96,27 @@ fn validate_method_call_expr(
 
 #[cfg(test)]
 mod tests {
-    use crate::tests::{self, check_assist};
+    use crate::tests::{check_assist, check_assist_not_applicable};
 
     use super::*;
 
-    const EMPTY_ITER_FIXTURE: &'static str = r"
-//- /lib.rs deps:core crate:empty_iter
-pub struct EmptyIter;
-impl Iterator for EmptyIter {
-    type Item = usize;
-    fn next(&mut self) -> Option<Self::Item> { None }
-}
-pub struct Empty;
-impl Empty {
-    pub fn iter(&self) -> EmptyIter { EmptyIter }
-}
-";
-
-    fn check_assist_with_fixtures(before: &str, after: &str) {
-        let before = &format!(
-            "//- /main.rs crate:main deps:core,empty_iter{}{}{}",
-            before,
-            EMPTY_ITER_FIXTURE,
-            FamousDefs::FIXTURE,
-        );
-        check_assist(convert_iter_for_each_to_for, before, after);
-    }
-
-    fn check_assist_not_applicable(before: &str) {
-        let before = &format!(
-            "//- /main.rs crate:main deps:core,empty_iter{}{}{}",
-            before,
-            EMPTY_ITER_FIXTURE,
-            FamousDefs::FIXTURE,
-        );
-        tests::check_assist_not_applicable(convert_iter_for_each_to_for, before);
-    }
-
     #[test]
     fn test_for_each_in_method_stmt() {
-        check_assist_with_fixtures(
+        check_assist(
+            convert_iter_for_each_to_for,
             r#"
-use empty_iter::*;
+//- minicore: iterators
 fn main() {
-    let x = Empty;
-    x.iter().$0for_each(|(x, y)| {
+    let it = core::iter::repeat(92);
+    it.$0for_each(|(x, y)| {
         println!("x: {}, y: {}", x, y);
     });
-}"#,
+}
+"#,
             r#"
-use empty_iter::*;
 fn main() {
-    let x = Empty;
-    for (x, y) in x.iter() {
+    let it = core::iter::repeat(92);
+    for (x, y) in it {
         println!("x: {}, y: {}", x, y);
     }
 }
@@ -160,43 +126,21 @@ fn main() {
 
     #[test]
     fn test_for_each_in_method() {
-        check_assist_with_fixtures(
+        check_assist(
+            convert_iter_for_each_to_for,
             r#"
-use empty_iter::*;
+//- minicore: iterators
 fn main() {
-    let x = Empty;
-    x.iter().$0for_each(|(x, y)| {
+    let it = core::iter::repeat(92);
+    it.$0for_each(|(x, y)| {
         println!("x: {}, y: {}", x, y);
     })
-}"#,
-            r#"
-use empty_iter::*;
-fn main() {
-    let x = Empty;
-    for (x, y) in x.iter() {
-        println!("x: {}, y: {}", x, y);
-    }
 }
 "#,
-        )
-    }
-
-    #[test]
-    fn test_for_each_in_iter_stmt() {
-        check_assist_with_fixtures(
-            r#"
-use empty_iter::*;
-fn main() {
-    let x = Empty.iter();
-    x.$0for_each(|(x, y)| {
-        println!("x: {}, y: {}", x, y);
-    });
-}"#,
             r#"
-use empty_iter::*;
 fn main() {
-    let x = Empty.iter();
-    for (x, y) in x {
+    let it = core::iter::repeat(92);
+    for (x, y) in it {
         println!("x: {}, y: {}", x, y);
     }
 }
@@ -206,18 +150,19 @@ fn main() {
 
     #[test]
     fn test_for_each_without_braces_stmt() {
-        check_assist_with_fixtures(
+        check_assist(
+            convert_iter_for_each_to_for,
             r#"
-use empty_iter::*;
+//- minicore: iterators
 fn main() {
-    let x = Empty;
-    x.iter().$0for_each(|(x, y)| println!("x: {}, y: {}", x, y));
-}"#,
+    let it = core::iter::repeat(92);
+    it.$0for_each(|(x, y)| println!("x: {}, y: {}", x, y));
+}
+"#,
             r#"
-use empty_iter::*;
 fn main() {
-    let x = Empty;
-    for (x, y) in x.iter() {
+    let it = core::iter::repeat(92);
+    for (x, y) in it {
         println!("x: {}, y: {}", x, y)
     }
 }
@@ -228,7 +173,9 @@ fn main() {
     #[test]
     fn test_for_each_not_applicable() {
         check_assist_not_applicable(
+            convert_iter_for_each_to_for,
             r#"
+//- minicore: iterators
 fn main() {
     ().$0for_each(|x| println!("{}", x));
 }"#,
@@ -237,11 +184,13 @@ fn main() {
 
     #[test]
     fn test_for_each_not_applicable_invalid_cursor_pos() {
+        cov_mark::check!(test_for_each_not_applicable_invalid_cursor_pos);
         check_assist_not_applicable(
+            convert_iter_for_each_to_for,
             r#"
-use empty_iter::*;
+//- minicore: iterators
 fn main() {
-    Empty.iter().for_each(|(x, y)| $0println!("x: {}, y: {}", x, y));
+    core::iter::repeat(92).for_each(|(x, y)| $0println!("x: {}, y: {}", x, y));
 }"#,
         )
     }
diff --git a/crates/ide_assists/src/handlers/extract_function.rs b/crates/ide_assists/src/handlers/extract_function.rs
index f2be091f4..870d4f665 100644
--- a/crates/ide_assists/src/handlers/extract_function.rs
+++ b/crates/ide_assists/src/handlers/extract_function.rs
@@ -109,10 +109,15 @@ pub(crate) fn extract_function(acc: &mut Assists, ctx: &AssistContext) -> Option
 
             let new_indent = IndentLevel::from_node(&insert_after);
             let old_indent = fun.body.indent_level();
+            let body_contains_await = body_contains_await(&fun.body);
 
-            builder.replace(target_range, format_replacement(ctx, &fun, old_indent));
+            builder.replace(
+                target_range,
+                format_replacement(ctx, &fun, old_indent, body_contains_await),
+            );
 
-            let fn_def = format_function(ctx, module, &fun, old_indent, new_indent);
+            let fn_def =
+                format_function(ctx, module, &fun, old_indent, new_indent, body_contains_await);
             let insert_offset = insert_after.text_range().end();
             match ctx.config.snippet_cap {
                 Some(cap) => builder.insert_snippet(cap, insert_offset, fn_def),
@@ -954,7 +959,12 @@ fn scope_for_fn_insertion_node(node: &SyntaxNode, anchor: Anchor) -> Option<Synt
     last_ancestor
 }
 
-fn format_replacement(ctx: &AssistContext, fun: &Function, indent: IndentLevel) -> String {
+fn format_replacement(
+    ctx: &AssistContext,
+    fun: &Function,
+    indent: IndentLevel,
+    body_contains_await: bool,
+) -> String {
     let ret_ty = fun.return_type(ctx);
 
     let args = fun.params.iter().map(|param| param.to_arg(ctx));
@@ -994,6 +1004,9 @@ fn format_replacement(ctx: &AssistContext, fun: &Function, indent: IndentLevel)
         }
     }
     format_to!(buf, "{}", expr);
+    if body_contains_await {
+        buf.push_str(".await");
+    }
     if fun.ret_ty.is_unit()
         && (!fun.vars_defined_in_body_and_outlive.is_empty() || !expr.is_block_like())
     {
@@ -1122,12 +1135,13 @@ fn format_function(
     fun: &Function,
     old_indent: IndentLevel,
     new_indent: IndentLevel,
+    body_contains_await: bool,
 ) -> String {
     let mut fn_def = String::new();
     let params = make_param_list(ctx, module, fun);
     let ret_ty = make_ret_ty(ctx, module, fun);
     let body = make_body(ctx, old_indent, new_indent, fun);
-    let async_kw = if body_contains_await(&fun.body) { "async " } else { "" };
+    let async_kw = if body_contains_await { "async " } else { "" };
     match ctx.config.snippet_cap {
         Some(_) => format_to!(fn_def, "\n\n{}{}fn $0{}{}", new_indent, async_kw, fun.name, params),
         None => format_to!(fn_def, "\n\n{}{}fn {}{}", new_indent, async_kw, fun.name, params),
@@ -1384,7 +1398,7 @@ fn fix_param_usages(ctx: &AssistContext, params: &[Param], syntax: &SyntaxNode)
     for (param, usages) in usages_for_param {
         for usage in usages {
             match usage.syntax().ancestors().skip(1).find_map(ast::Expr::cast) {
-                Some(ast::Expr::MethodCallExpr(_)) | Some(ast::Expr::FieldExpr(_)) => {
+                Some(ast::Expr::MethodCallExpr(_) | ast::Expr::FieldExpr(_)) => {
                     // do nothing
                 }
                 Some(ast::Expr::RefExpr(node))
@@ -1501,7 +1515,8 @@ mod tests {
             r#"
 fn foo() {
     foo($01 + 1$0);
-}"#,
+}
+"#,
             r#"
 fn foo() {
     foo(fun_name());
@@ -1509,7 +1524,8 @@ fn foo() {
 
 fn $0fun_name() -> i32 {
     1 + 1
-}"#,
+}
+"#,
         );
     }
 
@@ -1522,7 +1538,8 @@ mod bar {
     fn foo() {
         foo($01 + 1$0);
     }
-}"#,
+}
+"#,
             r#"
 mod bar {
     fn foo() {
@@ -1532,7 +1549,8 @@ mod bar {
     fn $0fun_name() -> i32 {
         1 + 1
     }
-}"#,
+}
+"#,
         );
     }
 
@@ -1543,7 +1561,8 @@ mod bar {
             r#"
 fn foo() {
     $0{ 1 + 1 }$0;
-}"#,
+}
+"#,
             r#"
 fn foo() {
     fun_name();
@@ -1551,7 +1570,8 @@ fn foo() {
 
 fn $0fun_name() -> i32 {
     1 + 1
-}"#,
+}
+"#,
         );
     }
 
@@ -1564,7 +1584,8 @@ fn foo() -> i32 {
     let k = 1;
     $0let m = 1;
     m + 1$0
-}"#,
+}
+"#,
             r#"
 fn foo() -> i32 {
     let k = 1;
@@ -1574,7 +1595,8 @@ fn foo() -> i32 {
 fn $0fun_name() -> i32 {
     let m = 1;
     m + 1
-}"#,
+}
+"#,
         );
     }
 
@@ -1588,7 +1610,8 @@ fn foo() {
     $0let m = 1;
     let n = m + 1;$0
     let g = 5;
-}"#,
+}
+"#,
             r#"
 fn foo() {
     let k = 3;
@@ -1599,7 +1622,8 @@ fn foo() {
 fn $0fun_name() {
     let m = 1;
     let n = m + 1;
-}"#,
+}
+"#,
         );
     }
 
@@ -1610,7 +1634,8 @@ fn $0fun_name() {
             r#"
 fn foo() {
     $0if true { }$0
-}"#,
+}
+"#,
             r#"
 fn foo() {
     fun_name();
@@ -1618,7 +1643,8 @@ fn foo() {
 
 fn $0fun_name() {
     if true { }
-}"#,
+}
+"#,
         );
     }
 
@@ -1629,7 +1655,8 @@ fn $0fun_name() {
             r#"
 fn foo() -> i32 {
     $0if true { 1 } else { 2 }$0
-}"#,
+}
+"#,
             r#"
 fn foo() -> i32 {
     fun_name()
@@ -1637,7 +1664,8 @@ fn foo() -> i32 {
 
 fn $0fun_name() -> i32 {
     if true { 1 } else { 2 }
-}"#,
+}
+"#,
         );
     }
 
@@ -1648,7 +1676,8 @@ fn $0fun_name() -> i32 {
             r#"
 fn foo() -> i32 {
     $0if let true = false { 1 } else { 2 }$0
-}"#,
+}
+"#,
             r#"
 fn foo() -> i32 {
     fun_name()
@@ -1656,7 +1685,8 @@ fn foo() -> i32 {
 
 fn $0fun_name() -> i32 {
     if let true = false { 1 } else { 2 }
-}"#,
+}
+"#,
         );
     }
 
@@ -1670,7 +1700,8 @@ fn foo() -> i32 {
         true => 1,
         false => 2,
     }$0
-}"#,
+}
+"#,
             r#"
 fn foo() -> i32 {
     fun_name()
@@ -1681,7 +1712,8 @@ fn $0fun_name() -> i32 {
         true => 1,
         false => 2,
     }
-}"#,
+}
+"#,
         );
     }
 
@@ -1692,7 +1724,8 @@ fn $0fun_name() -> i32 {
             r#"
 fn foo() {
     $0while true { }$0
-}"#,
+}
+"#,
             r#"
 fn foo() {
     fun_name();
@@ -1700,7 +1733,8 @@ fn foo() {
 
 fn $0fun_name() {
     while true { }
-}"#,
+}
+"#,
         );
     }
 
@@ -1711,7 +1745,8 @@ fn $0fun_name() {
             r#"
 fn foo() {
     $0for v in &[0, 1] { }$0
-}"#,
+}
+"#,
             r#"
 fn foo() {
     fun_name();
@@ -1719,7 +1754,8 @@ fn foo() {
 
 fn $0fun_name() {
     for v in &[0, 1] { }
-}"#,
+}
+"#,
         );
     }
 
@@ -1732,7 +1768,8 @@ fn foo() {
     $0loop {
         let m = 1;
     }$0
-}"#,
+}
+"#,
             r#"
 fn foo() {
     fun_name()
@@ -1742,7 +1779,8 @@ fn $0fun_name() -> ! {
     loop {
         let m = 1;
     }
-}"#,
+}
+"#,
         );
     }
 
@@ -1756,7 +1794,8 @@ fn foo() {
         let m = 1;
         break m;
     }$0;
-}"#,
+}
+"#,
             r#"
 fn foo() {
     let v = fun_name();
@@ -1767,7 +1806,8 @@ fn $0fun_name() -> i32 {
         let m = 1;
         break m;
     }
-}"#,
+}
+"#,
         );
     }
 
@@ -1781,7 +1821,8 @@ fn foo() {
         Some(x) => x,
         None => 0,
     }$0;
-}"#,
+}
+"#,
             r#"
 fn foo() {
     let v: i32 = fun_name();
@@ -1792,7 +1833,8 @@ fn $0fun_name() -> i32 {
         Some(x) => x,
         None => 0,
     }
-}"#,
+}
+"#,
         );
     }
 
@@ -1805,7 +1847,8 @@ fn foo() {
     let n = 1;
     let mut v = $0n * n;$0
     v += 1;
-}"#,
+}
+"#,
             r#"
 fn foo() {
     let n = 1;
@@ -1816,7 +1859,8 @@ fn foo() {
 fn $0fun_name(n: i32) -> i32 {
     let mut v = n * n;
     v
-}"#,
+}
+"#,
         );
     }
 
@@ -1832,7 +1876,8 @@ fn foo() {
     let mut w = 3;$0
     v += 1;
     w += 1;
-}"#,
+}
+"#,
             r#"
 fn foo() {
     let m = 2;
@@ -1846,7 +1891,8 @@ fn $0fun_name(m: i32, n: i32) -> (i32, i32) {
     let mut v = m * n;
     let mut w = 3;
     (v, w)
-}"#,
+}
+"#,
         );
     }
 
@@ -1854,12 +1900,13 @@ fn $0fun_name(m: i32, n: i32) -> (i32, i32) {
     fn argument_form_expr() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn foo() -> u32 {
     let n = 2;
     $0n+2$0
-}",
-            r"
+}
+"#,
+            r#"
 fn foo() -> u32 {
     let n = 2;
     fun_name(n)
@@ -1867,7 +1914,8 @@ fn foo() -> u32 {
 
 fn $0fun_name(n: u32) -> u32 {
     n+2
-}",
+}
+"#,
         )
     }
 
@@ -1875,12 +1923,13 @@ fn $0fun_name(n: u32) -> u32 {
     fn argument_used_twice_form_expr() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn foo() -> u32 {
     let n = 2;
     $0n+n$0
-}",
-            r"
+}
+"#,
+            r#"
 fn foo() -> u32 {
     let n = 2;
     fun_name(n)
@@ -1888,7 +1937,8 @@ fn foo() -> u32 {
 
 fn $0fun_name(n: u32) -> u32 {
     n+n
-}",
+}
+"#,
         )
     }
 
@@ -1896,13 +1946,14 @@ fn $0fun_name(n: u32) -> u32 {
     fn two_arguments_form_expr() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn foo() -> u32 {
     let n = 2;
     let m = 3;
     $0n+n*m$0
-}",
-            r"
+}
+"#,
+            r#"
 fn foo() -> u32 {
     let n = 2;
     let m = 3;
@@ -1911,7 +1962,8 @@ fn foo() -> u32 {
 
 fn $0fun_name(n: u32, m: u32) -> u32 {
     n+n*m
-}",
+}
+"#,
         )
     }
 
@@ -1919,13 +1971,14 @@ fn $0fun_name(n: u32, m: u32) -> u32 {
     fn argument_and_locals() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn foo() -> u32 {
     let n = 2;
     $0let m = 1;
     n + m$0
-}",
-            r"
+}
+"#,
+            r#"
 fn foo() -> u32 {
     let n = 2;
     fun_name(n)
@@ -1934,7 +1987,8 @@ fn foo() -> u32 {
 fn $0fun_name(n: u32) -> u32 {
     let m = 1;
     n + m
-}",
+}
+"#,
         )
     }
 
@@ -1948,18 +2002,20 @@ fn $0fun_name(n: u32) -> u32 {
     fn part_of_expr_stmt() {
         check_assist(
             extract_function,
-            "
+            r#"
 fn foo() {
     $01$0 + 1;
-}",
-            "
+}
+"#,
+            r#"
 fn foo() {
     fun_name() + 1;
 }
 
 fn $0fun_name() -> i32 {
     1
-}",
+}
+"#,
         );
     }
 
@@ -1970,7 +2026,8 @@ fn $0fun_name() -> i32 {
             r#"
 fn foo() {
     $0bar(1 + 1)$0
-}"#,
+}
+"#,
             r#"
 fn foo() {
     fun_name();
@@ -1978,7 +2035,8 @@ fn foo() {
 
 fn $0fun_name() {
     bar(1 + 1)
-}"#,
+}
+"#,
         )
     }
 
@@ -1986,15 +2044,16 @@ fn $0fun_name() {
     fn extract_from_nested() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn main() {
     let x = true;
     let tuple = match x {
         true => ($02 + 2$0, true)
         _ => (0, false)
     };
-}",
-            r"
+}
+"#,
+            r#"
 fn main() {
     let x = true;
     let tuple = match x {
@@ -2005,7 +2064,8 @@ fn main() {
 
 fn $0fun_name() -> i32 {
     2 + 2
-}",
+}
+"#,
         );
     }
 
@@ -2013,18 +2073,20 @@ fn $0fun_name() -> i32 {
     fn param_from_closure() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn main() {
     let lambda = |x: u32| $0x * 2$0;
-}",
-            r"
+}
+"#,
+            r#"
 fn main() {
     let lambda = |x: u32| fun_name(x);
 }
 
 fn $0fun_name(x: u32) -> u32 {
     x * 2
-}",
+}
+"#,
         );
     }
 
@@ -2032,18 +2094,20 @@ fn $0fun_name(x: u32) -> u32 {
     fn extract_return_stmt() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn foo() -> u32 {
     $0return 2 + 2$0;
-}",
-            r"
+}
+"#,
+            r#"
 fn foo() -> u32 {
     return fun_name();
 }
 
 fn $0fun_name() -> u32 {
     2 + 2
-}",
+}
+"#,
         );
     }
 
@@ -2051,13 +2115,14 @@ fn $0fun_name() -> u32 {
     fn does_not_add_extra_whitespace() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn foo() -> u32 {
 
 
     $0return 2 + 2$0;
-}",
-            r"
+}
+"#,
+            r#"
 fn foo() -> u32 {
 
 
@@ -2066,7 +2131,8 @@ fn foo() -> u32 {
 
 fn $0fun_name() -> u32 {
     2 + 2
-}",
+}
+"#,
         );
     }
 
@@ -2074,13 +2140,14 @@ fn $0fun_name() -> u32 {
     fn break_stmt() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn main() {
     let result = loop {
         $0break 2 + 2$0;
     };
-}",
-            r"
+}
+"#,
+            r#"
 fn main() {
     let result = loop {
         break fun_name();
@@ -2089,7 +2156,8 @@ fn main() {
 
 fn $0fun_name() -> i32 {
     2 + 2
-}",
+}
+"#,
         );
     }
 
@@ -2097,18 +2165,20 @@ fn $0fun_name() -> i32 {
     fn extract_cast() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn main() {
     let v = $00f32 as u32$0;
-}",
-            r"
+}
+"#,
+            r#"
 fn main() {
     let v = fun_name();
 }
 
 fn $0fun_name() -> u32 {
     0f32 as u32
-}",
+}
+"#,
         );
     }
 
@@ -2121,15 +2191,16 @@ fn $0fun_name() -> u32 {
     fn method_to_freestanding() {
         check_assist(
             extract_function,
-            r"
+            r#"
 struct S;
 
 impl S {
     fn foo(&self) -> i32 {
         $01+1$0
     }
-}",
-            r"
+}
+"#,
+            r#"
 struct S;
 
 impl S {
@@ -2140,7 +2211,8 @@ impl S {
 
 fn $0fun_name() -> i32 {
     1+1
-}",
+}
+"#,
         );
     }
 
@@ -2148,15 +2220,16 @@ fn $0fun_name() -> i32 {
     fn method_with_reference() {
         check_assist(
             extract_function,
-            r"
+            r#"
 struct S { f: i32 };
 
 impl S {
     fn foo(&self) -> i32 {
         $01+self.f$0
     }
-}",
-            r"
+}
+"#,
+            r#"
 struct S { f: i32 };
 
 impl S {
@@ -2167,7 +2240,8 @@ impl S {
     fn $0fun_name(&self) -> i32 {
         1+self.f
     }
-}",
+}
+"#,
         );
     }
 
@@ -2175,15 +2249,16 @@ impl S {
     fn method_with_mut() {
         check_assist(
             extract_function,
-            r"
+            r#"
 struct S { f: i32 };
 
 impl S {
     fn foo(&mut self) {
         $0self.f += 1;$0
     }
-}",
-            r"
+}
+"#,
+            r#"
 struct S { f: i32 };
 
 impl S {
@@ -2194,7 +2269,8 @@ impl S {
     fn $0fun_name(&mut self) {
         self.f += 1;
     }
-}",
+}
+"#,
         );
     }
 
@@ -2202,13 +2278,14 @@ impl S {
     fn variable_defined_inside_and_used_after_no_ret() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn foo() {
     let n = 1;
     $0let k = n * n;$0
     let m = k + 1;
-}",
-            r"
+}
+"#,
+            r#"
 fn foo() {
     let n = 1;
     let k = fun_name(n);
@@ -2218,7 +2295,8 @@ fn foo() {
 fn $0fun_name(n: i32) -> i32 {
     let k = n * n;
     k
-}",
+}
+"#,
         );
     }
 
@@ -2226,13 +2304,14 @@ fn $0fun_name(n: i32) -> i32 {
     fn variable_defined_inside_and_used_after_mutably_no_ret() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn foo() {
     let n = 1;
     $0let mut k = n * n;$0
     k += 1;
-}",
-            r"
+}
+"#,
+            r#"
 fn foo() {
     let n = 1;
     let mut k = fun_name(n);
@@ -2242,7 +2321,8 @@ fn foo() {
 fn $0fun_name(n: i32) -> i32 {
     let mut k = n * n;
     k
-}",
+}
+"#,
         );
     }
 
@@ -2250,14 +2330,15 @@ fn $0fun_name(n: i32) -> i32 {
     fn two_variables_defined_inside_and_used_after_no_ret() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn foo() {
     let n = 1;
     $0let k = n * n;
     let m = k + 2;$0
     let h = k + m;
-}",
-            r"
+}
+"#,
+            r#"
 fn foo() {
     let n = 1;
     let (k, m) = fun_name(n);
@@ -2268,7 +2349,8 @@ fn $0fun_name(n: i32) -> (i32, i32) {
     let k = n * n;
     let m = k + 2;
     (k, m)
-}",
+}
+"#,
         );
     }
 
@@ -2276,7 +2358,7 @@ fn $0fun_name(n: i32) -> (i32, i32) {
     fn multi_variables_defined_inside_and_used_after_mutably_no_ret() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn foo() {
     let n = 1;
     $0let mut k = n * n;
@@ -2285,8 +2367,9 @@ fn foo() {
     o += 1;$0
     k += o;
     m = 1;
-}",
-            r"
+}
+"#,
+            r#"
 fn foo() {
     let n = 1;
     let (mut k, mut m, o) = fun_name(n);
@@ -2300,7 +2383,8 @@ fn $0fun_name(n: i32) -> (i32, i32, i32) {
     let mut o = m + 3;
     o += 1;
     (k, m, o)
-}",
+}
+"#,
         );
     }
 
@@ -2308,13 +2392,14 @@ fn $0fun_name(n: i32) -> (i32, i32, i32) {
     fn nontrivial_patterns_define_variables() {
         check_assist(
             extract_function,
-            r"
+            r#"
 struct Counter(i32);
 fn foo() {
     $0let Counter(n) = Counter(0);$0
     let m = n;
-}",
-            r"
+}
+"#,
+            r#"
 struct Counter(i32);
 fn foo() {
     let n = fun_name();
@@ -2324,7 +2409,8 @@ fn foo() {
 fn $0fun_name() -> i32 {
     let Counter(n) = Counter(0);
     n
-}",
+}
+"#,
         );
     }
 
@@ -2332,13 +2418,14 @@ fn $0fun_name() -> i32 {
     fn struct_with_two_fields_pattern_define_variables() {
         check_assist(
             extract_function,
-            r"
+            r#"
 struct Counter { n: i32, m: i32 };
 fn foo() {
     $0let Counter { n, m: k } = Counter { n: 1, m: 2 };$0
     let h = n + k;
-}",
-            r"
+}
+"#,
+            r#"
 struct Counter { n: i32, m: i32 };
 fn foo() {
     let (n, k) = fun_name();
@@ -2348,7 +2435,8 @@ fn foo() {
 fn $0fun_name() -> (i32, i32) {
     let Counter { n, m: k } = Counter { n: 1, m: 2 };
     (n, k)
-}",
+}
+"#,
         );
     }
 
@@ -2356,13 +2444,14 @@ fn $0fun_name() -> (i32, i32) {
     fn mut_var_from_outer_scope() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn foo() {
     let mut n = 1;
     $0n += 1;$0
     let m = n + 1;
-}",
-            r"
+}
+"#,
+            r#"
 fn foo() {
     let mut n = 1;
     fun_name(&mut n);
@@ -2371,7 +2460,8 @@ fn foo() {
 
 fn $0fun_name(n: &mut i32) {
     *n += 1;
-}",
+}
+"#,
         );
     }
 
@@ -2379,14 +2469,15 @@ fn $0fun_name(n: &mut i32) {
     fn mut_field_from_outer_scope() {
         check_assist(
             extract_function,
-            r"
+            r#"
 struct C { n: i32 }
 fn foo() {
     let mut c = C { n: 0 };
     $0c.n += 1;$0
     let m = c.n + 1;
-}",
-            r"
+}
+"#,
+            r#"
 struct C { n: i32 }
 fn foo() {
     let mut c = C { n: 0 };
@@ -2396,7 +2487,8 @@ fn foo() {
 
 fn $0fun_name(c: &mut C) {
     c.n += 1;
-}",
+}
+"#,
         );
     }
 
@@ -2404,7 +2496,7 @@ fn $0fun_name(c: &mut C) {
     fn mut_nested_field_from_outer_scope() {
         check_assist(
             extract_function,
-            r"
+            r#"
 struct P { n: i32}
 struct C { p: P }
 fn foo() {
@@ -2414,8 +2506,9 @@ fn foo() {
     $0c.p.n += u.p.n;
     let r = &mut v.p.n;$0
     let m = c.p.n + v.p.n + u.p.n;
-}",
-            r"
+}
+"#,
+            r#"
 struct P { n: i32}
 struct C { p: P }
 fn foo() {
@@ -2429,7 +2522,8 @@ fn foo() {
 fn $0fun_name(c: &mut C, u: &C, v: &mut C) {
     c.p.n += u.p.n;
     let r = &mut v.p.n;
-}",
+}
+"#,
         );
     }
 
@@ -2437,7 +2531,7 @@ fn $0fun_name(c: &mut C, u: &C, v: &mut C) {
     fn mut_param_many_usages_stmt() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn bar(k: i32) {}
 trait I: Copy {
     fn succ(&self) -> Self;
@@ -2458,8 +2552,9 @@ fn foo() {
     *v = v.succ();
     n.succ();$0
     let m = n + 1;
-}",
-            r"
+}
+"#,
+            r#"
 fn bar(k: i32) {}
 trait I: Copy {
     fn succ(&self) -> Self;
@@ -2484,7 +2579,8 @@ fn $0fun_name(n: &mut i32) {
     let v = n;
     *v = v.succ();
     n.succ();
-}",
+}
+"#,
         );
     }
 
@@ -2492,7 +2588,7 @@ fn $0fun_name(n: &mut i32) {
     fn mut_param_many_usages_expr() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn bar(k: i32) {}
 trait I: Copy {
     fn succ(&self) -> Self;
@@ -2515,8 +2611,9 @@ fn foo() {
         n.succ();
     }$0
     let m = n + 1;
-}",
-            r"
+}
+"#,
+            r#"
 fn bar(k: i32) {}
 trait I: Copy {
     fn succ(&self) -> Self;
@@ -2541,7 +2638,8 @@ fn $0fun_name(n: &mut i32) {
     let v = n;
     *v = v.succ();
     n.succ();
-}",
+}
+"#,
         );
     }
 
@@ -2549,11 +2647,12 @@ fn $0fun_name(n: &mut i32) {
     fn mut_param_by_value() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn foo() {
     let mut n = 1;
     $0n += 1;$0
-}",
+}
+"#,
             r"
 fn foo() {
     let mut n = 1;
@@ -2562,7 +2661,8 @@ fn foo() {
 
 fn $0fun_name(mut n: i32) {
     n += 1;
-}",
+}
+",
         );
     }
 
@@ -2570,14 +2670,15 @@ fn $0fun_name(mut n: i32) {
     fn mut_param_because_of_mut_ref() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn foo() {
     let mut n = 1;
     $0let v = &mut n;
     *v += 1;$0
     let k = n;
-}",
-            r"
+}
+"#,
+            r#"
 fn foo() {
     let mut n = 1;
     fun_name(&mut n);
@@ -2587,7 +2688,8 @@ fn foo() {
 fn $0fun_name(n: &mut i32) {
     let v = n;
     *v += 1;
-}",
+}
+"#,
         );
     }
 
@@ -2600,8 +2702,9 @@ fn foo() {
     let mut n = 1;
     $0let v = &mut n;
     *v += 1;$0
-}",
-            r"
+}
+",
+            r#"
 fn foo() {
     let mut n = 1;
     fun_name(n);
@@ -2610,7 +2713,8 @@ fn foo() {
 fn $0fun_name(mut n: i32) {
     let v = &mut n;
     *v += 1;
-}",
+}
+"#,
         );
     }
 
@@ -2618,7 +2722,7 @@ fn $0fun_name(mut n: i32) {
     fn mut_method_call() {
         check_assist(
             extract_function,
-            r"
+            r#"
 trait I {
     fn inc(&mut self);
 }
@@ -2628,8 +2732,9 @@ impl I for i32 {
 fn foo() {
     let mut n = 1;
     $0n.inc();$0
-}",
-            r"
+}
+"#,
+            r#"
 trait I {
     fn inc(&mut self);
 }
@@ -2643,7 +2748,8 @@ fn foo() {
 
 fn $0fun_name(mut n: i32) {
     n.inc();
-}",
+}
+"#,
         );
     }
 
@@ -2651,7 +2757,7 @@ fn $0fun_name(mut n: i32) {
     fn shared_method_call() {
         check_assist(
             extract_function,
-            r"
+            r#"
 trait I {
     fn succ(&self);
 }
@@ -2661,7 +2767,8 @@ impl I for i32 {
 fn foo() {
     let mut n = 1;
     $0n.succ();$0
-}",
+}
+"#,
             r"
 trait I {
     fn succ(&self);
@@ -2676,7 +2783,8 @@ fn foo() {
 
 fn $0fun_name(n: i32) {
     n.succ();
-}",
+}
+",
         );
     }
 
@@ -2684,7 +2792,7 @@ fn $0fun_name(n: i32) {
     fn mut_method_call_with_other_receiver() {
         check_assist(
             extract_function,
-            r"
+            r#"
 trait I {
     fn inc(&mut self, n: i32);
 }
@@ -2695,7 +2803,8 @@ fn foo() {
     let mut n = 1;
     $0let mut m = 2;
     m.inc(n);$0
-}",
+}
+"#,
             r"
 trait I {
     fn inc(&mut self, n: i32);
@@ -2711,7 +2820,8 @@ fn foo() {
 fn $0fun_name(n: i32) {
     let mut m = 2;
     m.inc(n);
-}",
+}
+",
         );
     }
 
@@ -2719,12 +2829,13 @@ fn $0fun_name(n: i32) {
     fn non_copy_without_usages_after() {
         check_assist(
             extract_function,
-            r"
+            r#"
 struct Counter(i32);
 fn foo() {
     let c = Counter(0);
     $0let n = c.0;$0
-}",
+}
+"#,
             r"
 struct Counter(i32);
 fn foo() {
@@ -2734,7 +2845,8 @@ fn foo() {
 
 fn $0fun_name(c: Counter) {
     let n = c.0;
-}",
+}
+",
         );
     }
 
@@ -2748,8 +2860,9 @@ fn foo() {
     let c = Counter(0);
     $0let n = c.0;$0
     let m = c.0;
-}",
-            r"
+}
+",
+            r#"
 struct Counter(i32);
 fn foo() {
     let c = Counter(0);
@@ -2759,7 +2872,8 @@ fn foo() {
 
 fn $0fun_name(c: &Counter) {
     let n = c.0;
-}",
+}
+"#,
         );
     }
 
@@ -2767,19 +2881,15 @@ fn $0fun_name(c: &Counter) {
     fn copy_used_after() {
         check_assist(
             extract_function,
-            r##"
-#[lang = "copy"]
-pub trait Copy {}
-impl Copy for i32 {}
+            r#"
+//- minicore: copy
 fn foo() {
     let n = 0;
     $0let m = n;$0
     let k = n;
-}"##,
-            r##"
-#[lang = "copy"]
-pub trait Copy {}
-impl Copy for i32 {}
+}
+"#,
+            r#"
 fn foo() {
     let n = 0;
     fun_name(n);
@@ -2788,7 +2898,8 @@ fn foo() {
 
 fn $0fun_name(n: i32) {
     let m = n;
-}"##,
+}
+"#,
         )
     }
 
@@ -2796,21 +2907,19 @@ fn $0fun_name(n: i32) {
     fn copy_custom_used_after() {
         check_assist(
             extract_function,
-            r##"
-#[lang = "copy"]
-pub trait Copy {}
+            r#"
+//- minicore: copy, derive
+#[derive(Clone, Copy)]
 struct Counter(i32);
-impl Copy for Counter {}
 fn foo() {
     let c = Counter(0);
     $0let n = c.0;$0
     let m = c.0;
-}"##,
-            r##"
-#[lang = "copy"]
-pub trait Copy {}
+}
+"#,
+            r#"
+#[derive(Clone, Copy)]
 struct Counter(i32);
-impl Copy for Counter {}
 fn foo() {
     let c = Counter(0);
     fun_name(c);
@@ -2819,7 +2928,8 @@ fn foo() {
 
 fn $0fun_name(c: Counter) {
     let n = c.0;
-}"##,
+}
+"#,
         );
     }
 
@@ -2827,7 +2937,7 @@ fn $0fun_name(c: Counter) {
     fn indented_stmts() {
         check_assist(
             extract_function,
-            r"
+            r#"
 fn foo() {
     if true {
         loop {
@@ -2835,8 +2945,9 @@ fn foo() {
             let m = 2;$0
         }
     }
-}",
-            r"
+}
+"#,
+            r#"
 fn foo() {
     if true {
         loop {
@@ -2848,7 +2959,8 @@ fn foo() {
 fn $0fun_name() {
     let n = 1;
     let m = 2;
-}",
+}
+"#,
         );
     }
 
@@ -2856,7 +2968,7 @@ fn $0fun_name() {
     fn indented_stmts_inside_mod() {
         check_assist(
             extract_function,
-            r"
+            r#"
 mod bar {
     fn foo() {
         if true {
@@ -2866,8 +2978,9 @@ mod bar {
             }
         }
     }
-}",
-            r"
+}
+"#,
+            r#"
 mod bar {
     fn foo() {
         if true {
@@ -2881,7 +2994,8 @@ mod bar {
         let n = 1;
         let m = 2;
     }
-}",
+}
+"#,
         );
     }
 
@@ -2889,12 +3003,8 @@ mod bar {
     fn break_loop() {
         check_assist(
             extract_function,
-            r##"
-enum Option<T> {
-    #[lang = "None"] None,
-    #[lang = "Some"] Some(T),
-}
-use Option::*;
+            r#"
+//- minicore: option
 fn foo() {
     loop {
         let n = 1;
@@ -2903,13 +3013,9 @@ fn foo() {
         let k = 2;$0
         let h = 1 + k;
     }
-}"##,
-            r##"
-enum Option<T> {
-    #[lang = "None"] None,
-    #[lang = "Some"] Some(T),
 }
-use Option::*;
+"#,
+            r#"
 fn foo() {
     loop {
         let n = 1;
@@ -2926,7 +3032,8 @@ fn $0fun_name(n: i32) -> Option<i32> {
     return None;
     let k = 2;
     Some(k)
-}"##,
+}
+"#,
         );
     }
 
@@ -2934,31 +3041,17 @@ fn $0fun_name(n: i32) -> Option<i32> {
     fn return_to_parent() {
         check_assist(
             extract_function,
-            r##"
-#[lang = "copy"]
-pub trait Copy {}
-impl Copy for i32 {}
-enum Result<T, E> {
-    #[lang = "Ok"] Ok(T),
-    #[lang = "Err"] Err(E),
-}
-use Result::*;
+            r#"
+//- minicore: copy, result
 fn foo() -> i64 {
     let n = 1;
     $0let m = n + 1;
     return 1;
     let k = 2;$0
     (n + k) as i64
-}"##,
-            r##"
-#[lang = "copy"]
-pub trait Copy {}
-impl Copy for i32 {}
-enum Result<T, E> {
-    #[lang = "Ok"] Ok(T),
-    #[lang = "Err"] Err(E),
-}
-use Result::*;
+}
+"#,
+            r#"
 fn foo() -> i64 {
     let n = 1;
     let k = match fun_name(n) {
@@ -2973,7 +3066,8 @@ fn $0fun_name(n: i32) -> Result<i32, i64> {
     return Err(1);
     let k = 2;
     Ok(k)
-}"##,
+}
+"#,
         );
     }
 
@@ -2982,7 +3076,7 @@ fn $0fun_name(n: i32) -> Result<i32, i64> {
         cov_mark::check!(external_control_flow_break_and_continue);
         check_assist_not_applicable(
             extract_function,
-            r##"
+            r#"
 fn foo() {
     loop {
         let n = 1;
@@ -2993,7 +3087,8 @@ fn foo() {
         let k = k + 1;$0
         let r = n + k;
     }
-}"##,
+}
+"#,
         );
     }
 
@@ -3002,7 +3097,7 @@ fn foo() {
         cov_mark::check!(external_control_flow_return_and_bc);
         check_assist_not_applicable(
             extract_function,
-            r##"
+            r#"
 fn foo() {
     loop {
         let n = 1;
@@ -3013,7 +3108,8 @@ fn foo() {
         let k = k + 1;$0
         let r = n + k;
     }
-}"##,
+}
+"#,
         );
     }
 
@@ -3021,7 +3117,7 @@ fn foo() {
     fn break_loop_with_if() {
         check_assist(
             extract_function,
-            r##"
+            r#"
 fn foo() {
     loop {
         let mut n = 1;
@@ -3030,8 +3126,9 @@ fn foo() {
         n += m;$0
         let h = 1 + n;
     }
-}"##,
-            r##"
+}
+"#,
+            r#"
 fn foo() {
     loop {
         let mut n = 1;
@@ -3047,7 +3144,8 @@ fn $0fun_name(n: &mut i32) -> bool {
     return true;
     *n += m;
     false
-}"##,
+}
+"#,
         );
     }
 
@@ -3055,7 +3153,7 @@ fn $0fun_name(n: &mut i32) -> bool {
     fn break_loop_nested() {
         check_assist(
             extract_function,
-            r##"
+            r#"
 fn foo() {
     loop {
         let mut n = 1;
@@ -3065,8 +3163,9 @@ fn foo() {
         }$0
         let h = 1;
     }
-}"##,
-            r##"
+}
+"#,
+            r#"
 fn foo() {
     loop {
         let mut n = 1;
@@ -3083,7 +3182,8 @@ fn $0fun_name(n: i32) -> bool {
         return true;
     }
     false
-}"##,
+}
+"#,
         );
     }
 
@@ -3091,7 +3191,7 @@ fn $0fun_name(n: i32) -> bool {
     fn return_from_nested_loop() {
         check_assist(
             extract_function,
-            r##"
+            r#"
 fn foo() {
     loop {
         let n = 1;
@@ -3103,8 +3203,9 @@ fn foo() {
         let m = k + 1;$0
         let h = 1 + m;
     }
-}"##,
-            r##"
+}
+"#,
+            r#"
 fn foo() {
     loop {
         let n = 1;
@@ -3123,7 +3224,8 @@ fn $0fun_name() -> Option<i32> {
     }
     let m = k + 1;
     Some(m)
-}"##,
+}
+"#,
         );
     }
 
@@ -3131,7 +3233,7 @@ fn $0fun_name() -> Option<i32> {
     fn break_from_nested_loop() {
         check_assist(
             extract_function,
-            r##"
+            r#"
 fn foo() {
     loop {
         let n = 1;
@@ -3142,8 +3244,9 @@ fn foo() {
         let m = k + 1;$0
         let h = 1 + m;
     }
-}"##,
-            r##"
+}
+"#,
+            r#"
 fn foo() {
     loop {
         let n = 1;
@@ -3159,7 +3262,8 @@ fn $0fun_name() -> i32 {
     }
     let m = k + 1;
     m
-}"##,
+}
+"#,
         );
     }
 
@@ -3167,7 +3271,7 @@ fn $0fun_name() -> i32 {
     fn break_from_nested_and_outer_loops() {
         check_assist(
             extract_function,
-            r##"
+            r#"
 fn foo() {
     loop {
         let n = 1;
@@ -3181,8 +3285,9 @@ fn foo() {
         let m = k + 1;$0
         let h = 1 + m;
     }
-}"##,
-            r##"
+}
+"#,
+            r#"
 fn foo() {
     loop {
         let n = 1;
@@ -3204,7 +3309,8 @@ fn $0fun_name() -> Option<i32> {
     }
     let m = k + 1;
     Some(m)
-}"##,
+}
+"#,
         );
     }
 
@@ -3212,7 +3318,7 @@ fn $0fun_name() -> Option<i32> {
     fn return_from_nested_fn() {
         check_assist(
             extract_function,
-            r##"
+            r#"
 fn foo() {
     loop {
         let n = 1;
@@ -3223,8 +3329,9 @@ fn foo() {
         let m = k + 1;$0
         let h = 1 + m;
     }
-}"##,
-            r##"
+}
+"#,
+            r#"
 fn foo() {
     loop {
         let n = 1;
@@ -3240,7 +3347,8 @@ fn $0fun_name() -> i32 {
     }
     let m = k + 1;
     m
-}"##,
+}
+"#,
         );
     }
 
@@ -3248,7 +3356,7 @@ fn $0fun_name() -> i32 {
     fn break_with_value() {
         check_assist(
             extract_function,
-            r##"
+            r#"
 fn foo() -> i32 {
     loop {
         let n = 1;
@@ -3259,8 +3367,9 @@ fn foo() -> i32 {
         let m = k + 1;$0
         let h = 1;
     }
-}"##,
-            r##"
+}
+"#,
+            r#"
 fn foo() -> i32 {
     loop {
         let n = 1;
@@ -3278,7 +3387,8 @@ fn $0fun_name() -> Option<i32> {
     }
     let m = k + 1;
     None
-}"##,
+}
+"#,
         );
     }
 
@@ -3286,7 +3396,7 @@ fn $0fun_name() -> Option<i32> {
     fn break_with_value_and_return() {
         check_assist(
             extract_function,
-            r##"
+            r#"
 fn foo() -> i64 {
     loop {
         let n = 1;
@@ -3298,8 +3408,9 @@ fn foo() -> i64 {
         let m = k + 1;$0
         let h = 1 + m;
     }
-}"##,
-            r##"
+}
+"#,
+            r#"
 fn foo() -> i64 {
     loop {
         let n = 1;
@@ -3318,7 +3429,8 @@ fn $0fun_name() -> Result<i32, i64> {
     }
     let m = k + 1;
     Ok(m)
-}"##,
+}
+"#,
         );
     }
 
@@ -3326,9 +3438,8 @@ fn $0fun_name() -> Result<i32, i64> {
     fn try_option() {
         check_assist(
             extract_function,
-            r##"
-enum Option<T> { None, Some(T), }
-use Option::*;
+            r#"
+//- minicore: option
 fn bar() -> Option<i32> { None }
 fn foo() -> Option<()> {
     let n = bar()?;
@@ -3336,10 +3447,9 @@ fn foo() -> Option<()> {
     let m = k + 1;$0
     let h = 1 + m;
     Some(())
-}"##,
-            r##"
-enum Option<T> { None, Some(T), }
-use Option::*;
+}
+"#,
+            r#"
 fn bar() -> Option<i32> { None }
 fn foo() -> Option<()> {
     let n = bar()?;
@@ -3352,7 +3462,8 @@ fn $0fun_name() -> Option<i32> {
     let k = foo()?;
     let m = k + 1;
     Some(m)
-}"##,
+}
+"#,
         );
     }
 
@@ -3360,19 +3471,17 @@ fn $0fun_name() -> Option<i32> {
     fn try_option_unit() {
         check_assist(
             extract_function,
-            r##"
-enum Option<T> { None, Some(T), }
-use Option::*;
+            r#"
+//- minicore: option
 fn foo() -> Option<()> {
     let n = 1;
     $0let k = foo()?;
     let m = k + 1;$0
     let h = 1 + n;
     Some(())
-}"##,
-            r##"
-enum Option<T> { None, Some(T), }
-use Option::*;
+}
+"#,
+            r#"
 fn foo() -> Option<()> {
     let n = 1;
     fun_name()?;
@@ -3384,7 +3493,8 @@ fn $0fun_name() -> Option<()> {
     let k = foo()?;
     let m = k + 1;
     Some(())
-}"##,
+}
+"#,
         );
     }
 
@@ -3392,19 +3502,17 @@ fn $0fun_name() -> Option<()> {
     fn try_result() {
         check_assist(
             extract_function,
-            r##"
-enum Result<T, E> { Ok(T), Err(E), }
-use Result::*;
+            r#"
+//- minicore: result
 fn foo() -> Result<(), i64> {
     let n = 1;
     $0let k = foo()?;
     let m = k + 1;$0
     let h = 1 + m;
     Ok(())
-}"##,
-            r##"
-enum Result<T, E> { Ok(T), Err(E), }
-use Result::*;
+}
+"#,
+            r#"
 fn foo() -> Result<(), i64> {
     let n = 1;
     let m = fun_name()?;
@@ -3416,7 +3524,8 @@ fn $0fun_name() -> Result<i32, i64> {
     let k = foo()?;
     let m = k + 1;
     Ok(m)
-}"##,
+}
+"#,
         );
     }
 
@@ -3424,9 +3533,8 @@ fn $0fun_name() -> Result<i32, i64> {
     fn try_option_with_return() {
         check_assist(
             extract_function,
-            r##"
-enum Option<T> { None, Some(T) }
-use Option::*;
+            r#"
+//- minicore: option
 fn foo() -> Option<()> {
     let n = 1;
     $0let k = foo()?;
@@ -3436,10 +3544,9 @@ fn foo() -> Option<()> {
     let m = k + 1;$0
     let h = 1 + m;
     Some(())
-}"##,
-            r##"
-enum Option<T> { None, Some(T) }
-use Option::*;
+}
+"#,
+            r#"
 fn foo() -> Option<()> {
     let n = 1;
     let m = fun_name()?;
@@ -3454,7 +3561,8 @@ fn $0fun_name() -> Option<i32> {
     }
     let m = k + 1;
     Some(m)
-}"##,
+}
+"#,
         );
     }
 
@@ -3462,9 +3570,8 @@ fn $0fun_name() -> Option<i32> {
     fn try_result_with_return() {
         check_assist(
             extract_function,
-            r##"
-enum Result<T, E> { Ok(T), Err(E), }
-use Result::*;
+            r#"
+//- minicore: result
 fn foo() -> Result<(), i64> {
     let n = 1;
     $0let k = foo()?;
@@ -3474,10 +3581,9 @@ fn foo() -> Result<(), i64> {
     let m = k + 1;$0
     let h = 1 + m;
     Ok(())
-}"##,
-            r##"
-enum Result<T, E> { Ok(T), Err(E), }
-use Result::*;
+}
+"#,
+            r#"
 fn foo() -> Result<(), i64> {
     let n = 1;
     let m = fun_name()?;
@@ -3492,7 +3598,8 @@ fn $0fun_name() -> Result<i32, i64> {
     }
     let m = k + 1;
     Ok(m)
-}"##,
+}
+"#,
         );
     }
 
@@ -3501,9 +3608,8 @@ fn $0fun_name() -> Result<i32, i64> {
         cov_mark::check!(external_control_flow_try_and_bc);
         check_assist_not_applicable(
             extract_function,
-            r##"
-enum Option<T> { None, Some(T) }
-use Option::*;
+            r#"
+//- minicore: option
 fn foo() -> Option<()> {
     loop {
         let n = Some(1);
@@ -3514,7 +3620,8 @@ fn foo() -> Option<()> {
         let r = n + k;
     }
     Some(())
-}"##,
+}
+"#,
         );
     }
 
@@ -3523,9 +3630,8 @@ fn foo() -> Option<()> {
         cov_mark::check!(external_control_flow_try_and_return_non_err);
         check_assist_not_applicable(
             extract_function,
-            r##"
-enum Result<T, E> { Ok(T), Err(E), }
-use Result::*;
+            r#"
+//- minicore: result
 fn foo() -> Result<(), i64> {
     let n = 1;
     $0let k = foo()?;
@@ -3535,7 +3641,8 @@ fn foo() -> Result<(), i64> {
     let m = k + 1;$0
     let h = 1 + m;
     Ok(())
-}"##,
+}
+"#,
         );
     }
 
@@ -3543,7 +3650,7 @@ fn foo() -> Result<(), i64> {
     fn param_usage_in_macro() {
         check_assist(
             extract_function,
-            r"
+            r#"
 macro_rules! m {
     ($val:expr) => { $val };
 }
@@ -3552,8 +3659,9 @@ fn foo() {
     let n = 1;
     $0let k = n * m!(n);$0
     let m = k + 1;
-}",
-            r"
+}
+"#,
+            r#"
 macro_rules! m {
     ($val:expr) => { $val };
 }
@@ -3567,7 +3675,8 @@ fn foo() {
 fn $0fun_name(n: i32) -> i32 {
     let k = n * m!(n);
     k
-}",
+}
+"#,
         );
     }
 
@@ -3575,7 +3684,8 @@ fn $0fun_name(n: i32) -> i32 {
     fn extract_with_await() {
         check_assist(
             extract_function,
-            r#"fn main() {
+            r#"
+fn main() {
     $0some_function().await;$0
 }
 
@@ -3585,7 +3695,7 @@ async fn some_function() {
 "#,
             r#"
 fn main() {
-    fun_name();
+    fun_name().await;
 }
 
 async fn $0fun_name() {
@@ -3603,7 +3713,8 @@ async fn some_function() {
     fn extract_with_await_in_args() {
         check_assist(
             extract_function,
-            r#"fn main() {
+            r#"
+fn main() {
     $0function_call("a", some_function().await);$0
 }
 
@@ -3613,7 +3724,7 @@ async fn some_function() {
 "#,
             r#"
 fn main() {
-    fun_name();
+    fun_name().await;
 }
 
 async fn $0fun_name() {
diff --git a/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs b/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs
index d3ff7b65c..430710448 100644
--- a/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs
+++ b/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs
@@ -48,6 +48,7 @@ pub(crate) fn extract_struct_from_enum_variant(
     let variant_name = variant.name()?;
     let variant_hir = ctx.sema.to_def(&variant)?;
     if existing_definition(ctx.db(), &variant_name, &variant_hir) {
+        cov_mark::hit!(test_extract_enum_not_applicable_if_struct_exists);
         return None;
     }
 
@@ -235,7 +236,7 @@ fn apply_references(
     import: Option<(ImportScope, hir::ModPath)>,
 ) {
     if let Some((scope, path)) = import {
-        insert_use(&scope, mod_path_to_ast(&path), insert_use_cfg);
+        insert_use(&scope, mod_path_to_ast(&path), &insert_use_cfg);
     }
     // deep clone to prevent cycle
     let path = make::path_from_segments(iter::once(segment.clone_subtree()), false);
@@ -300,18 +301,10 @@ fn reference_to_node(
 
 #[cfg(test)]
 mod tests {
-    use ide_db::helpers::FamousDefs;
-
     use crate::tests::{check_assist, check_assist_not_applicable};
 
     use super::*;
 
-    fn check_not_applicable(ra_fixture: &str) {
-        let fixture =
-            format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
-        check_assist_not_applicable(extract_struct_from_enum_variant, &fixture)
-    }
-
     #[test]
     fn test_extract_struct_several_fields_tuple() {
         check_assist(
@@ -699,29 +692,33 @@ fn foo() {
 
     #[test]
     fn test_extract_enum_not_applicable_for_element_with_no_fields() {
-        check_not_applicable("enum A { $0One }");
+        check_assist_not_applicable(extract_struct_from_enum_variant, r#"enum A { $0One }"#);
     }
 
     #[test]
     fn test_extract_enum_not_applicable_if_struct_exists() {
-        check_not_applicable(
-            r#"struct One;
-        enum A { $0One(u8, u32) }"#,
+        cov_mark::check!(test_extract_enum_not_applicable_if_struct_exists);
+        check_assist_not_applicable(
+            extract_struct_from_enum_variant,
+            r#"
+struct One;
+enum A { $0One(u8, u32) }
+"#,
         );
     }
 
     #[test]
     fn test_extract_not_applicable_one_field() {
-        check_not_applicable(r"enum A { $0One(u32) }");
+        check_assist_not_applicable(extract_struct_from_enum_variant, r"enum A { $0One(u32) }");
     }
 
     #[test]
     fn test_extract_not_applicable_no_field_tuple() {
-        check_not_applicable(r"enum A { $0None() }");
+        check_assist_not_applicable(extract_struct_from_enum_variant, r"enum A { $0None() }");
     }
 
     #[test]
     fn test_extract_not_applicable_no_field_named() {
-        check_not_applicable(r"enum A { $0None {} }");
+        check_assist_not_applicable(extract_struct_from_enum_variant, r"enum A { $0None {} }");
     }
 }
diff --git a/crates/ide_assists/src/handlers/fill_match_arms.rs b/crates/ide_assists/src/handlers/fill_match_arms.rs
index 5a43bdd6f..318faa0fc 100644
--- a/crates/ide_assists/src/handlers/fill_match_arms.rs
+++ b/crates/ide_assists/src/handlers/fill_match_arms.rs
@@ -278,8 +278,6 @@ fn build_pat(db: &RootDatabase, module: hir::Module, var: ExtendedVariant) -> Op
 
 #[cfg(test)]
 mod tests {
-    use ide_db::helpers::FamousDefs;
-
     use crate::tests::{
         check_assist, check_assist_not_applicable, check_assist_target, check_assist_unresolved,
     };
@@ -483,26 +481,21 @@ fn main() {
         check_assist(
             fill_match_arms,
             r#"
-enum Option<T> { Some(T), None }
-use Option::*;
-
+//- minicore: option
 fn main() {
     match None$0 {
         None => {}
     }
 }
-            "#,
+"#,
             r#"
-enum Option<T> { Some(T), None }
-use Option::*;
-
 fn main() {
     match None {
         None => {}
         Some(${0:_}) => todo!(),
     }
 }
-            "#,
+"#,
         );
     }
 
@@ -716,7 +709,10 @@ fn main() {
 
     #[test]
     fn fill_match_arms_tuple_of_enum_partial_with_wildcards() {
-        let ra_fixture = r#"
+        check_assist(
+            fill_match_arms,
+            r#"
+//- minicore: option
 fn main() {
     let a = Some(1);
     let b = Some(());
@@ -725,10 +721,7 @@ fn main() {
         (None, Some(_)) => {}
     }
 }
-"#;
-        check_assist(
-            fill_match_arms,
-            &format!("//- /main.rs crate:main deps:core{}{}", ra_fixture, FamousDefs::FIXTURE),
+"#,
             r#"
 fn main() {
     let a = Some(1);
@@ -746,17 +739,17 @@ fn main() {
     #[test]
     fn fill_match_arms_partial_with_deep_pattern() {
         // Fixme: cannot handle deep patterns
-        let ra_fixture = r#"
+        check_assist_not_applicable(
+            fill_match_arms,
+            r#"
+//- minicore: option
 fn main() {
     match $0Some(true) {
         Some(true) => {}
         None => {}
     }
 }
-"#;
-        check_assist_not_applicable(
-            fill_match_arms,
-            &format!("//- /main.rs crate:main deps:core{}{}", ra_fixture, FamousDefs::FIXTURE),
+"#,
         );
     }
 
@@ -1007,17 +1000,15 @@ fn foo(a: A) {
     #[test]
     fn option_order() {
         cov_mark::check!(option_order);
-        let before = r#"
+        check_assist(
+            fill_match_arms,
+            r#"
+//- minicore: option
 fn foo(opt: Option<i32>) {
     match opt$0 {
     }
 }
-"#;
-        let before = &format!("//- /main.rs crate:main deps:core{}{}", before, FamousDefs::FIXTURE);
-
-        check_assist(
-            fill_match_arms,
-            before,
+"#,
             r#"
 fn foo(opt: Option<i32>) {
     match opt {
diff --git a/crates/ide_assists/src/handlers/fix_visibility.rs b/crates/ide_assists/src/handlers/fix_visibility.rs
index 9b432e92f..f834bf16a 100644
--- a/crates/ide_assists/src/handlers/fix_visibility.rs
+++ b/crates/ide_assists/src/handlers/fix_visibility.rs
@@ -361,8 +361,6 @@ pub struct Foo { pub bar: () }
     }
 
     #[test]
-    #[ignore]
-    // FIXME reenable this test when `Semantics::resolve_record_field` works with union fields
     fn fix_visibility_of_union_field() {
         check_assist(
             fix_visibility,
@@ -583,25 +581,25 @@ pub struct Foo { pub(crate) bar: () }
     }
 
     #[test]
-    #[ignore]
-    // FIXME handle reexports properly
     fn fix_visibility_of_reexport() {
+        // FIXME: broken test, this should fix visibility of the re-export
+        // rather than the struct.
         check_assist(
             fix_visibility,
-            r"
-            mod foo {
-                use bar::Baz;
-                mod bar { pub(super) struct Baz; }
-            }
-            foo::Baz$0
-            ",
-            r"
-            mod foo {
-                $0pub(crate) use bar::Baz;
-                mod bar { pub(super) struct Baz; }
-            }
-            foo::Baz
-            ",
+            r#"
+mod foo {
+    use bar::Baz;
+    mod bar { pub(super) struct Baz; }
+}
+foo::Baz$0
+"#,
+            r#"
+mod foo {
+    use bar::Baz;
+    mod bar { $0pub(crate) struct Baz; }
+}
+foo::Baz
+"#,
         )
     }
 }
diff --git a/crates/ide_assists/src/handlers/generate_default_from_enum_variant.rs b/crates/ide_assists/src/handlers/generate_default_from_enum_variant.rs
index 588ee1350..e55c38502 100644
--- a/crates/ide_assists/src/handlers/generate_default_from_enum_variant.rs
+++ b/crates/ide_assists/src/handlers/generate_default_from_enum_variant.rs
@@ -1,5 +1,4 @@
-use ide_db::helpers::FamousDefs;
-use ide_db::RootDatabase;
+use ide_db::{helpers::FamousDefs, RootDatabase};
 use syntax::ast::{self, AstNode, NameOwner};
 
 use crate::{AssistContext, AssistId, AssistKind, Assists};
@@ -92,23 +91,20 @@ mod tests {
 
     use super::*;
 
-    fn check_not_applicable(ra_fixture: &str) {
-        let fixture =
-            format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
-        check_assist_not_applicable(generate_default_from_enum_variant, &fixture)
-    }
-
     #[test]
     fn test_generate_default_from_variant() {
         check_assist(
             generate_default_from_enum_variant,
             r#"
+//- minicore: default
 enum Variant {
     Undefined,
     Minor$0,
     Major,
-}"#,
-            r#"enum Variant {
+}
+"#,
+            r#"
+enum Variant {
     Undefined,
     Minor,
     Major,
@@ -118,15 +114,18 @@ impl Default for Variant {
     fn default() -> Self {
         Self::Minor
     }
-}"#,
+}
+"#,
         );
     }
 
     #[test]
     fn test_generate_default_already_implemented() {
         cov_mark::check!(test_gen_default_impl_already_exists);
-        check_not_applicable(
+        check_assist_not_applicable(
+            generate_default_from_enum_variant,
             r#"
+//- minicore: default
 enum Variant {
     Undefined,
     Minor$0,
@@ -137,20 +136,24 @@ impl Default for Variant {
     fn default() -> Self {
         Self::Minor
     }
-}"#,
+}
+"#,
         );
     }
 
     #[test]
     fn test_add_from_impl_no_element() {
         cov_mark::check!(test_gen_default_on_non_unit_variant_not_implemented);
-        check_not_applicable(
+        check_assist_not_applicable(
+            generate_default_from_enum_variant,
             r#"
+//- minicore: default
 enum Variant {
     Undefined,
     Minor(u32)$0,
     Major,
-}"#,
+}
+"#,
         );
     }
 
@@ -158,7 +161,10 @@ enum Variant {
     fn test_generate_default_from_variant_with_one_variant() {
         check_assist(
             generate_default_from_enum_variant,
-            r#"enum Variant { Undefi$0ned }"#,
+            r#"
+//- minicore: default
+enum Variant { Undefi$0ned }
+"#,
             r#"
 enum Variant { Undefined }
 
@@ -166,7 +172,8 @@ impl Default for Variant {
     fn default() -> Self {
         Self::Undefined
     }
-}"#,
+}
+"#,
         );
     }
 }
diff --git a/crates/ide_assists/src/handlers/generate_default_from_new.rs b/crates/ide_assists/src/handlers/generate_default_from_new.rs
index bad826366..b54ec59da 100644
--- a/crates/ide_assists/src/handlers/generate_default_from_new.rs
+++ b/crates/ide_assists/src/handlers/generate_default_from_new.rs
@@ -1,7 +1,3 @@
-use crate::{
-    assist_context::{AssistContext, Assists},
-    AssistId,
-};
 use ide_db::helpers::FamousDefs;
 use itertools::Itertools;
 use stdx::format_to;
@@ -10,6 +6,11 @@ use syntax::{
     AstNode,
 };
 
+use crate::{
+    assist_context::{AssistContext, Assists},
+    AssistId,
+};
+
 // Assist: generate_default_from_new
 //
 // Generates default implementation from new method.
@@ -140,16 +141,16 @@ fn is_default_implemented(ctx: &AssistContext, impl_: &Impl) -> bool {
 
 #[cfg(test)]
 mod tests {
-    use ide_db::helpers::FamousDefs;
-
     use crate::tests::{check_assist, check_assist_not_applicable};
 
     use super::*;
 
     #[test]
     fn generate_default() {
-        check_pass(
+        check_assist(
+            generate_default_from_new,
             r#"
+//- minicore: default
 struct Example { _inner: () }
 
 impl Example {
@@ -182,8 +183,10 @@ fn main() {}
 
     #[test]
     fn generate_default2() {
-        check_pass(
+        check_assist(
+            generate_default_from_new,
             r#"
+//- minicore: default
 struct Test { value: u32 }
 
 impl Test {
@@ -212,8 +215,10 @@ impl Default for Test {
 
     #[test]
     fn new_function_with_generic() {
-        check_pass(
+        check_assist(
+            generate_default_from_new,
             r#"
+//- minicore: default
 pub struct Foo<T> {
     _bar: *mut T,
 }
@@ -246,8 +251,10 @@ impl<T> Default for Foo<T> {
 
     #[test]
     fn new_function_with_generics() {
-        check_pass(
+        check_assist(
+            generate_default_from_new,
             r#"
+//- minicore: default
 pub struct Foo<T, B> {
     _tars: *mut T,
     _bar: *mut B,
@@ -282,8 +289,10 @@ impl<T, B> Default for Foo<T, B> {
 
     #[test]
     fn new_function_with_generic_and_bound() {
-        check_pass(
+        check_assist(
+            generate_default_from_new,
             r#"
+//- minicore: default
 pub struct Foo<T> {
     t: T,
 }
@@ -316,8 +325,10 @@ impl<T: From<i32>> Default for Foo<T> {
 
     #[test]
     fn new_function_with_generics_and_bounds() {
-        check_pass(
+        check_assist(
+            generate_default_from_new,
             r#"
+//- minicore: default
 pub struct Foo<T, B> {
     _tars: T,
     _bar: B,
@@ -352,8 +363,10 @@ impl<T: From<i32>, B: From<i64>> Default for Foo<T, B> {
 
     #[test]
     fn new_function_with_generic_and_where() {
-        check_pass(
+        check_assist(
+            generate_default_from_new,
             r#"
+//- minicore: default
 pub struct Foo<T> {
     t: T,
 }
@@ -395,8 +408,10 @@ where
 
     #[test]
     fn new_function_with_generics_and_wheres() {
-        check_pass(
+        check_assist(
+            generate_default_from_new,
             r#"
+//- minicore: default
 pub struct Foo<T, B> {
     _tars: T,
     _bar: B,
@@ -441,8 +456,10 @@ where
     #[test]
     fn new_function_with_parameters() {
         cov_mark::check!(new_function_with_parameters);
-        check_not_applicable(
+        check_assist_not_applicable(
+            generate_default_from_new,
             r#"
+//- minicore: default
 struct Example { _inner: () }
 
 impl Example {
@@ -457,7 +474,8 @@ impl Example {
     #[test]
     fn other_function_than_new() {
         cov_mark::check!(other_function_than_new);
-        check_not_applicable(
+        check_assist_not_applicable(
+            generate_default_from_new,
             r#"
 struct Example { _inner: () }
 
@@ -474,8 +492,10 @@ impl Example {
     #[test]
     fn default_block_is_already_present() {
         cov_mark::check!(default_block_is_already_present);
-        check_not_applicable(
+        check_assist_not_applicable(
+            generate_default_from_new,
             r#"
+//- minicore: default
 struct Example { _inner: () }
 
 impl Example {
@@ -495,7 +515,8 @@ impl Default for Example {
 
     #[test]
     fn standalone_new_function() {
-        check_not_applicable(
+        check_assist_not_applicable(
+            generate_default_from_new,
             r#"
 fn n$0ew() -> u32 {
     0
@@ -506,8 +527,10 @@ fn n$0ew() -> u32 {
 
     #[test]
     fn multiple_struct_blocks() {
-        check_pass(
+        check_assist(
+            generate_default_from_new,
             r#"
+//- minicore: default
 struct Example { _inner: () }
 struct Test { value: u32 }
 
@@ -538,8 +561,10 @@ impl Default for Example {
 
     #[test]
     fn when_struct_is_after_impl() {
-        check_pass(
+        check_assist(
+            generate_default_from_new,
             r#"
+//- minicore: default
 impl Example {
     pub fn $0new() -> Self {
         Self { _inner: () }
@@ -568,8 +593,10 @@ struct Example { _inner: () }
 
     #[test]
     fn struct_in_module() {
-        check_pass(
+        check_assist(
+            generate_default_from_new,
             r#"
+//- minicore: default
 mod test {
     struct Example { _inner: () }
 
@@ -603,8 +630,10 @@ impl Default for Example {
     #[test]
     fn struct_in_module_with_default() {
         cov_mark::check!(struct_in_module_with_default);
-        check_not_applicable(
+        check_assist_not_applicable(
+            generate_default_from_new,
             r#"
+//- minicore: default
 mod test {
     struct Example { _inner: () }
 
@@ -623,14 +652,4 @@ mod test {
 "#,
         );
     }
-
-    fn check_pass(before: &str, after: &str) {
-        let before = &format!("//- /main.rs crate:main deps:core{}{}", before, FamousDefs::FIXTURE);
-        check_assist(generate_default_from_new, before, after);
-    }
-
-    fn check_not_applicable(before: &str) {
-        let before = &format!("//- /main.rs crate:main deps:core{}{}", before, FamousDefs::FIXTURE);
-        check_assist_not_applicable(generate_default_from_new, before);
-    }
 }
diff --git a/crates/ide_assists/src/handlers/generate_deref.rs b/crates/ide_assists/src/handlers/generate_deref.rs
index 4998ff7a4..4e10fdb85 100644
--- a/crates/ide_assists/src/handlers/generate_deref.rs
+++ b/crates/ide_assists/src/handlers/generate_deref.rs
@@ -182,23 +182,17 @@ impl std::ops::Deref for B {
         );
     }
 
-    fn check_not_applicable(ra_fixture: &str) {
-        let fixture = format!(
-            "//- /main.rs crate:main deps:core,std\n{}\n{}",
-            ra_fixture,
-            FamousDefs::FIXTURE
-        );
-        check_assist_not_applicable(generate_deref, &fixture)
-    }
-
     #[test]
     fn test_generate_record_deref_not_applicable_if_already_impl() {
         cov_mark::check!(test_add_record_deref_impl_already_exists);
-        check_not_applicable(
-            r#"struct A { }
+        check_assist_not_applicable(
+            generate_deref,
+            r#"
+//- minicore: deref
+struct A { }
 struct B { $0a: A }
 
-impl std::ops::Deref for B {
+impl core::ops::Deref for B {
     type Target = A;
 
     fn deref(&self) -> &Self::Target {
@@ -211,11 +205,14 @@ impl std::ops::Deref for B {
     #[test]
     fn test_generate_field_deref_not_applicable_if_already_impl() {
         cov_mark::check!(test_add_field_deref_impl_already_exists);
-        check_not_applicable(
-            r#"struct A { }
+        check_assist_not_applicable(
+            generate_deref,
+            r#"
+//- minicore: deref
+struct A { }
 struct B($0A)
 
-impl std::ops::Deref for B {
+impl core::ops::Deref for B {
     type Target = A;
 
     fn deref(&self) -> &Self::Target {
diff --git a/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs b/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs
index ce6998d82..8727be07d 100644
--- a/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs
+++ b/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs
@@ -110,14 +110,19 @@ mod tests {
     fn test_generate_from_impl_for_enum() {
         check_assist(
             generate_from_impl_for_enum,
-            "enum A { $0One(u32) }",
-            r#"enum A { One(u32) }
+            r#"
+//- minicore: from
+enum A { $0One(u32) }
+"#,
+            r#"
+enum A { One(u32) }
 
 impl From<u32> for A {
     fn from(v: u32) -> Self {
         Self::One(v)
     }
-}"#,
+}
+"#,
         );
     }
 
@@ -125,53 +130,71 @@ impl From<u32> for A {
     fn test_generate_from_impl_for_enum_complicated_path() {
         check_assist(
             generate_from_impl_for_enum,
-            r#"enum A { $0One(foo::bar::baz::Boo) }"#,
-            r#"enum A { One(foo::bar::baz::Boo) }
+            r#"
+//- minicore: from
+enum A { $0One(foo::bar::baz::Boo) }
+"#,
+            r#"
+enum A { One(foo::bar::baz::Boo) }
 
 impl From<foo::bar::baz::Boo> for A {
     fn from(v: foo::bar::baz::Boo) -> Self {
         Self::One(v)
     }
-}"#,
+}
+"#,
         );
     }
 
-    fn check_not_applicable(ra_fixture: &str) {
-        let fixture =
-            format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
-        check_assist_not_applicable(generate_from_impl_for_enum, &fixture)
-    }
-
     #[test]
     fn test_add_from_impl_no_element() {
-        check_not_applicable("enum A { $0One }");
+        check_assist_not_applicable(
+            generate_from_impl_for_enum,
+            r#"
+//- minicore: from
+enum A { $0One }
+"#,
+        );
     }
 
     #[test]
     fn test_add_from_impl_more_than_one_element_in_tuple() {
-        check_not_applicable("enum A { $0One(u32, String) }");
+        check_assist_not_applicable(
+            generate_from_impl_for_enum,
+            r#"
+//- minicore: from
+enum A { $0One(u32, String) }
+"#,
+        );
     }
 
     #[test]
     fn test_add_from_impl_struct_variant() {
         check_assist(
             generate_from_impl_for_enum,
-            "enum A { $0One { x: u32 } }",
-            r#"enum A { One { x: u32 } }
+            r#"
+//- minicore: from
+enum A { $0One { x: u32 } }
+"#,
+            r#"
+enum A { One { x: u32 } }
 
 impl From<u32> for A {
     fn from(x: u32) -> Self {
         Self::One { x }
     }
-}"#,
+}
+"#,
         );
     }
 
     #[test]
     fn test_add_from_impl_already_exists() {
         cov_mark::check!(test_add_from_impl_already_exists);
-        check_not_applicable(
+        check_assist_not_applicable(
+            generate_from_impl_for_enum,
             r#"
+//- minicore: from
 enum A { $0One(u32), }
 
 impl From<u32> for A {
@@ -187,7 +210,9 @@ impl From<u32> for A {
     fn test_add_from_impl_different_variant_impl_exists() {
         check_assist(
             generate_from_impl_for_enum,
-            r#"enum A { $0One(u32), Two(String), }
+            r#"
+//- minicore: from
+enum A { $0One(u32), Two(String), }
 
 impl From<String> for A {
     fn from(v: String) -> Self {
@@ -197,8 +222,10 @@ impl From<String> for A {
 
 pub trait From<T> {
     fn from(T) -> Self;
-}"#,
-            r#"enum A { One(u32), Two(String), }
+}
+"#,
+            r#"
+enum A { One(u32), Two(String), }
 
 impl From<u32> for A {
     fn from(v: u32) -> Self {
@@ -214,7 +241,8 @@ impl From<String> for A {
 
 pub trait From<T> {
     fn from(T) -> Self;
-}"#,
+}
+"#,
         );
     }
 
@@ -222,14 +250,19 @@ pub trait From<T> {
     fn test_add_from_impl_static_str() {
         check_assist(
             generate_from_impl_for_enum,
-            "enum A { $0One(&'static str) }",
-            r#"enum A { One(&'static str) }
+            r#"
+//- minicore: from
+enum A { $0One(&'static str) }
+"#,
+            r#"
+enum A { One(&'static str) }
 
 impl From<&'static str> for A {
     fn from(v: &'static str) -> Self {
         Self::One(v)
     }
-}"#,
+}
+"#,
         );
     }
 
@@ -237,14 +270,19 @@ impl From<&'static str> for A {
     fn test_add_from_impl_generic_enum() {
         check_assist(
             generate_from_impl_for_enum,
-            "enum Generic<T, U: Clone> { $0One(T), Two(U) }",
-            r#"enum Generic<T, U: Clone> { One(T), Two(U) }
+            r#"
+//- minicore: from
+enum Generic<T, U: Clone> { $0One(T), Two(U) }
+"#,
+            r#"
+enum Generic<T, U: Clone> { One(T), Two(U) }
 
 impl<T, U: Clone> From<T> for Generic<T, U> {
     fn from(v: T) -> Self {
         Self::One(v)
     }
-}"#,
+}
+"#,
         );
     }
 
@@ -252,14 +290,19 @@ impl<T, U: Clone> From<T> for Generic<T, U> {
     fn test_add_from_impl_with_lifetime() {
         check_assist(
             generate_from_impl_for_enum,
-            "enum Generic<'a> { $0One(&'a i32) }",
-            r#"enum Generic<'a> { One(&'a i32) }
+            r#"
+//- minicore: from
+enum Generic<'a> { $0One(&'a i32) }
+"#,
+            r#"
+enum Generic<'a> { One(&'a i32) }
 
 impl<'a> From<&'a i32> for Generic<'a> {
     fn from(v: &'a i32) -> Self {
         Self::One(v)
     }
-}"#,
+}
+"#,
         );
     }
 }
diff --git a/crates/ide_assists/src/handlers/generate_function.rs b/crates/ide_assists/src/handlers/generate_function.rs
index 706c995ac..6a658d4cf 100644
--- a/crates/ide_assists/src/handlers/generate_function.rs
+++ b/crates/ide_assists/src/handlers/generate_function.rs
@@ -811,9 +811,8 @@ fn bar(baz: Baz::Bof) ${0:-> ()} {
     }
 
     #[test]
-    #[ignore]
-    // FIXME fix printing the generics of a `Ty` to make this test pass
     fn add_function_with_generic_arg() {
+        // FIXME: This is wrong, generated `bar` should include generic parameter.
         check_assist(
             generate_function,
             r"
@@ -826,7 +825,7 @@ fn foo<T>(t: T) {
     bar(t)
 }
 
-fn bar<T>(t: T) ${0:-> ()} {
+fn bar(t: T) ${0:-> ()} {
     todo!()
 }
 ",
@@ -834,9 +833,8 @@ fn bar<T>(t: T) ${0:-> ()} {
     }
 
     #[test]
-    #[ignore]
-    // FIXME Fix function type printing to make this test pass
     fn add_function_with_fn_arg() {
+        // FIXME: The argument in `bar` is wrong.
         check_assist(
             generate_function,
             r"
@@ -857,7 +855,7 @@ fn foo() {
     bar(Baz::new);
 }
 
-fn bar(arg: fn() -> Baz) ${0:-> ()} {
+fn bar(new: fn) ${0:-> ()} {
     todo!()
 }
 ",
@@ -865,9 +863,8 @@ fn bar(arg: fn() -> Baz) ${0:-> ()} {
     }
 
     #[test]
-    #[ignore]
-    // FIXME Fix closure type printing to make this test pass
     fn add_function_with_closure_arg() {
+        // FIXME: The argument in `bar` is wrong.
         check_assist(
             generate_function,
             r"
@@ -882,7 +879,7 @@ fn foo() {
     bar(closure)
 }
 
-fn bar(closure: impl Fn(i64) -> i64) ${0:-> ()} {
+fn bar(closure: ()) ${0:-> ()} {
     todo!()
 }
 ",
@@ -986,13 +983,10 @@ fn foo() {
     }
 
     #[test]
-    #[ignore]
-    // Ignored until local imports are supported.
-    // See https://github.com/rust-analyzer/rust-analyzer/issues/1165
     fn qualified_path_uses_correct_scope() {
         check_assist(
             generate_function,
-            "
+            r#"
 mod foo {
     pub struct Foo;
 }
@@ -1001,8 +995,8 @@ fn bar() {
     let foo = Foo;
     baz$0(foo)
 }
-",
-            "
+"#,
+            r#"
 mod foo {
     pub struct Foo;
 }
@@ -1015,7 +1009,7 @@ fn bar() {
 fn baz(foo: foo::Foo) ${0:-> ()} {
     todo!()
 }
-",
+"#,
         )
     }
 
@@ -1141,40 +1135,29 @@ fn bar() {}
             // The assist is only active if the cursor is on an unresolved path,
             // but the assist should only be offered if the path is a function call.
             generate_function,
-            r"
+            r#"
 fn foo() {
     bar(b$0az);
 }
 
 fn bar(baz: ()) {}
-",
+"#,
         )
     }
 
     #[test]
-    #[ignore]
     fn create_method_with_no_args() {
-        check_assist(
+        // FIXME: This is wrong, this should just work.
+        check_assist_not_applicable(
             generate_function,
-            r"
+            r#"
 struct Foo;
 impl Foo {
     fn foo(&self) {
         self.bar()$0;
     }
 }
-        ",
-            r"
-struct Foo;
-impl Foo {
-    fn foo(&self) {
-        self.bar();
-    }
-    fn bar(&self) {
-        todo!();
-    }
-}
-        ",
+        "#,
         )
     }
 }
diff --git a/crates/ide_assists/src/handlers/inline_local_variable.rs b/crates/ide_assists/src/handlers/inline_local_variable.rs
index 2441dbb8b..945d28650 100644
--- a/crates/ide_assists/src/handlers/inline_local_variable.rs
+++ b/crates/ide_assists/src/handlers/inline_local_variable.rs
@@ -65,32 +65,35 @@ pub(crate) fn inline_local_variable(acc: &mut Assists, ctx: &AssistContext) -> O
                         Some(u) => u,
                         None => return Some(false),
                     };
-
-                    Some(!matches!(
-                        (&initializer_expr, usage_parent),
-                        (ast::Expr::CallExpr(_), _)
-                            | (ast::Expr::IndexExpr(_), _)
-                            | (ast::Expr::MethodCallExpr(_), _)
-                            | (ast::Expr::FieldExpr(_), _)
-                            | (ast::Expr::TryExpr(_), _)
-                            | (ast::Expr::RefExpr(_), _)
-                            | (ast::Expr::Literal(_), _)
-                            | (ast::Expr::TupleExpr(_), _)
-                            | (ast::Expr::ArrayExpr(_), _)
-                            | (ast::Expr::ParenExpr(_), _)
-                            | (ast::Expr::PathExpr(_), _)
-                            | (ast::Expr::BlockExpr(_), _)
-                            | (ast::Expr::EffectExpr(_), _)
-                            | (_, ast::Expr::CallExpr(_))
-                            | (_, ast::Expr::TupleExpr(_))
-                            | (_, ast::Expr::ArrayExpr(_))
-                            | (_, ast::Expr::ParenExpr(_))
-                            | (_, ast::Expr::ForExpr(_))
-                            | (_, ast::Expr::WhileExpr(_))
-                            | (_, ast::Expr::BreakExpr(_))
-                            | (_, ast::Expr::ReturnExpr(_))
-                            | (_, ast::Expr::MatchExpr(_))
-                    ))
+                    Some(
+                        !(matches!(
+                            initializer_expr,
+                            ast::Expr::CallExpr(_)
+                                | ast::Expr::IndexExpr(_)
+                                | ast::Expr::MethodCallExpr(_)
+                                | ast::Expr::FieldExpr(_)
+                                | ast::Expr::TryExpr(_)
+                                | ast::Expr::RefExpr(_)
+                                | ast::Expr::Literal(_)
+                                | ast::Expr::TupleExpr(_)
+                                | ast::Expr::ArrayExpr(_)
+                                | ast::Expr::ParenExpr(_)
+                                | ast::Expr::PathExpr(_)
+                                | ast::Expr::BlockExpr(_)
+                                | ast::Expr::EffectExpr(_),
+                        ) || matches!(
+                            usage_parent,
+                            ast::Expr::CallExpr(_)
+                                | ast::Expr::TupleExpr(_)
+                                | ast::Expr::ArrayExpr(_)
+                                | ast::Expr::ParenExpr(_)
+                                | ast::Expr::ForExpr(_)
+                                | ast::Expr::WhileExpr(_)
+                                | ast::Expr::BreakExpr(_)
+                                | ast::Expr::ReturnExpr(_)
+                                | ast::Expr::MatchExpr(_)
+                        )),
+                    )
                 })
                 .collect::<Option<_>>()
                 .map(|b| (file_id, b))
diff --git a/crates/ide_assists/src/handlers/move_module_to_file.rs b/crates/ide_assists/src/handlers/move_module_to_file.rs
index 93f702c55..cfc54be8d 100644
--- a/crates/ide_assists/src/handlers/move_module_to_file.rs
+++ b/crates/ide_assists/src/handlers/move_module_to_file.rs
@@ -1,5 +1,8 @@
+use std::iter;
+
 use ast::edit::IndentLevel;
 use ide_db::base_db::AnchoredPathBuf;
+use itertools::Itertools;
 use stdx::format_to;
 use syntax::{
     ast::{self, edit::AstNodeEdit, NameOwner},
@@ -34,7 +37,10 @@ pub(crate) fn move_module_to_file(acc: &mut Assists, ctx: &AssistContext) -> Opt
 
     let module_name = module_ast.name()?;
 
-    let module_def = ctx.sema.to_def(&module_ast)?;
+    // get to the outermost module syntax so we can grab the module of file we are in
+    let outermost_mod_decl =
+        iter::successors(Some(module_ast.clone()), |module| module.parent()).last()?;
+    let module_def = ctx.sema.to_def(&outermost_mod_decl)?;
     let parent_module = module_def.parent(ctx.db())?;
 
     acc.add(
@@ -43,11 +49,19 @@ pub(crate) fn move_module_to_file(acc: &mut Assists, ctx: &AssistContext) -> Opt
         target,
         |builder| {
             let path = {
-                let dir = match parent_module.name(ctx.db()) {
-                    Some(name) if !parent_module.is_mod_rs(ctx.db()) => format!("{}/", name),
-                    _ => String::new(),
-                };
-                format!("./{}{}.rs", dir, module_name)
+                let mut buf = String::from("./");
+                match parent_module.name(ctx.db()) {
+                    Some(name) if !parent_module.is_mod_rs(ctx.db()) => {
+                        format_to!(buf, "{}/", name)
+                    }
+                    _ => (),
+                }
+                let segments = iter::successors(Some(module_ast.clone()), |module| module.parent())
+                    .filter_map(|it| it.name())
+                    .collect::<Vec<_>>();
+                format_to!(buf, "{}", segments.into_iter().rev().format("/"));
+                format_to!(buf, ".rs");
+                buf
             };
             let contents = {
                 let items = module_items.dedent(IndentLevel(1)).to_string();
@@ -59,14 +73,13 @@ pub(crate) fn move_module_to_file(acc: &mut Assists, ctx: &AssistContext) -> Opt
                 items
             };
 
-            let mut buf = String::new();
-            format_to!(buf, "mod {};", module_name);
+            let buf = format!("mod {};", module_name);
 
-            let replacement_start = if let Some(mod_token) = module_ast.mod_token() {
-                mod_token.text_range().start()
-            } else {
-                module_ast.syntax().text_range().start()
-            };
+            let replacement_start = match module_ast.mod_token() {
+                Some(mod_token) => mod_token.text_range(),
+                None => module_ast.syntax().text_range(),
+            }
+            .start();
 
             builder.replace(
                 TextRange::new(replacement_start, module_ast.syntax().text_range().end()),
@@ -212,4 +225,30 @@ mod tests;
 "#,
         );
     }
+
+    #[test]
+    fn extract_nested() {
+        check_assist(
+            move_module_to_file,
+            r#"
+//- /lib.rs
+mod foo;
+//- /foo.rs
+mod bar {
+    mod baz {
+        mod qux$0 {}
+    }
+}
+"#,
+            r#"
+//- /foo.rs
+mod bar {
+    mod baz {
+        mod qux;
+    }
+}
+//- /foo/bar/baz/qux.rs
+"#,
+        );
+    }
 }
diff --git a/crates/ide_assists/src/handlers/qualify_path.rs b/crates/ide_assists/src/handlers/qualify_path.rs
index f91770a76..1d7be183a 100644
--- a/crates/ide_assists/src/handlers/qualify_path.rs
+++ b/crates/ide_assists/src/handlers/qualify_path.rs
@@ -216,28 +216,28 @@ mod tests {
         cov_mark::check!(qualify_path_unqualified_name);
         check_assist(
             qualify_path,
-            r"
-            mod std {
-                pub mod fmt {
-                    pub struct Formatter;
-                }
-            }
+            r#"
+mod std {
+    pub mod fmt {
+        pub struct Formatter;
+    }
+}
 
-            use std::fmt;
+use std::fmt;
 
-            $0Formatter
-            ",
-            r"
-            mod std {
-                pub mod fmt {
-                    pub struct Formatter;
-                }
-            }
+$0Formatter
+"#,
+            r#"
+mod std {
+    pub mod fmt {
+        pub struct Formatter;
+    }
+}
 
-            use std::fmt;
+use std::fmt;
 
-            fmt::Formatter
-            ",
+fmt::Formatter
+"#,
         );
     }
 
@@ -245,20 +245,20 @@ mod tests {
     fn applicable_when_found_an_import() {
         check_assist(
             qualify_path,
-            r"
-            $0PubStruct
+            r#"
+$0PubStruct
 
-            pub mod PubMod {
-                pub struct PubStruct;
-            }
-            ",
-            r"
-            PubMod::PubStruct
+pub mod PubMod {
+    pub struct PubStruct;
+}
+"#,
+            r#"
+PubMod::PubStruct
 
-            pub mod PubMod {
-                pub struct PubStruct;
-            }
-            ",
+pub mod PubMod {
+    pub struct PubStruct;
+}
+"#,
         );
     }
 
@@ -266,26 +266,26 @@ mod tests {
     fn applicable_in_macros() {
         check_assist(
             qualify_path,
-            r"
-            macro_rules! foo {
-                ($i:ident) => { fn foo(a: $i) {} }
-            }
-            foo!(Pub$0Struct);
+            r#"
+macro_rules! foo {
+    ($i:ident) => { fn foo(a: $i) {} }
+}
+foo!(Pub$0Struct);
 
-            pub mod PubMod {
-                pub struct PubStruct;
-            }
-            ",
-            r"
-            macro_rules! foo {
-                ($i:ident) => { fn foo(a: $i) {} }
-            }
-            foo!(PubMod::PubStruct);
+pub mod PubMod {
+    pub struct PubStruct;
+}
+"#,
+            r#"
+macro_rules! foo {
+    ($i:ident) => { fn foo(a: $i) {} }
+}
+foo!(PubMod::PubStruct);
 
-            pub mod PubMod {
-                pub struct PubStruct;
-            }
-            ",
+pub mod PubMod {
+    pub struct PubStruct;
+}
+"#,
         );
     }
 
@@ -293,32 +293,32 @@ mod tests {
     fn applicable_when_found_multiple_imports() {
         check_assist(
             qualify_path,
-            r"
-            PubSt$0ruct
+            r#"
+PubSt$0ruct
 
-            pub mod PubMod1 {
-                pub struct PubStruct;
-            }
-            pub mod PubMod2 {
-                pub struct PubStruct;
-            }
-            pub mod PubMod3 {
-                pub struct PubStruct;
-            }
-            ",
-            r"
-            PubMod3::PubStruct
+pub mod PubMod1 {
+    pub struct PubStruct;
+}
+pub mod PubMod2 {
+    pub struct PubStruct;
+}
+pub mod PubMod3 {
+    pub struct PubStruct;
+}
+"#,
+            r#"
+PubMod3::PubStruct
 
-            pub mod PubMod1 {
-                pub struct PubStruct;
-            }
-            pub mod PubMod2 {
-                pub struct PubStruct;
-            }
-            pub mod PubMod3 {
-                pub struct PubStruct;
-            }
-            ",
+pub mod PubMod1 {
+    pub struct PubStruct;
+}
+pub mod PubMod2 {
+    pub struct PubStruct;
+}
+pub mod PubMod3 {
+    pub struct PubStruct;
+}
+"#,
         );
     }
 
@@ -326,15 +326,15 @@ mod tests {
     fn not_applicable_for_already_imported_types() {
         check_assist_not_applicable(
             qualify_path,
-            r"
-            use PubMod::PubStruct;
+            r#"
+use PubMod::PubStruct;
 
-            PubStruct$0
+PubStruct$0
 
-            pub mod PubMod {
-                pub struct PubStruct;
-            }
-            ",
+pub mod PubMod {
+    pub struct PubStruct;
+}
+"#,
         );
     }
 
@@ -342,35 +342,32 @@ mod tests {
     fn not_applicable_for_types_with_private_paths() {
         check_assist_not_applicable(
             qualify_path,
-            r"
-            PrivateStruct$0
+            r#"
+PrivateStruct$0
 
-            pub mod PubMod {
-                struct PrivateStruct;
-            }
-            ",
+pub mod PubMod {
+    struct PrivateStruct;
+}
+"#,
         );
     }
 
     #[test]
     fn not_applicable_when_no_imports_found() {
-        check_assist_not_applicable(
-            qualify_path,
-            "
-            PubStruct$0",
-        );
+        check_assist_not_applicable(qualify_path, r#"PubStruct$0"#);
     }
 
     #[test]
     fn not_applicable_in_import_statements() {
         check_assist_not_applicable(
             qualify_path,
-            r"
-            use PubStruct$0;
+            r#"
+use PubStruct$0;
 
-            pub mod PubMod {
-                pub struct PubStruct;
-            }",
+pub mod PubMod {
+    pub struct PubStruct;
+}
+"#,
         );
     }
 
@@ -378,20 +375,20 @@ mod tests {
     fn qualify_function() {
         check_assist(
             qualify_path,
-            r"
-            test_function$0
+            r#"
+test_function$0
 
-            pub mod PubMod {
-                pub fn test_function() {};
-            }
-            ",
-            r"
-            PubMod::test_function
+pub mod PubMod {
+    pub fn test_function() {};
+}
+"#,
+            r#"
+PubMod::test_function
 
-            pub mod PubMod {
-                pub fn test_function() {};
-            }
-            ",
+pub mod PubMod {
+    pub fn test_function() {};
+}
+"#,
         );
     }
 
@@ -399,7 +396,7 @@ mod tests {
     fn qualify_macro() {
         check_assist(
             qualify_path,
-            r"
+            r#"
 //- /lib.rs crate:crate_with_macro
 #[macro_export]
 macro_rules! foo {
@@ -410,12 +407,12 @@ macro_rules! foo {
 fn main() {
     foo$0
 }
-",
-            r"
+"#,
+            r#"
 fn main() {
     crate_with_macro::foo
 }
-",
+"#,
         );
     }
 
@@ -423,13 +420,13 @@ fn main() {
     fn qualify_path_target() {
         check_assist_target(
             qualify_path,
-            r"
-            struct AssistInfo {
-                group_label: Option<$0GroupLabel>,
-            }
+            r#"
+struct AssistInfo {
+    group_label: Option<$0GroupLabel>,
+}
 
-            mod m { pub struct GroupLabel; }
-            ",
+mod m { pub struct GroupLabel; }
+"#,
             "GroupLabel",
         )
     }
@@ -438,20 +435,20 @@ fn main() {
     fn not_applicable_when_path_start_is_imported() {
         check_assist_not_applicable(
             qualify_path,
-            r"
-            pub mod mod1 {
-                pub mod mod2 {
-                    pub mod mod3 {
-                        pub struct TestStruct;
-                    }
-                }
-            }
+            r#"
+pub mod mod1 {
+    pub mod mod2 {
+        pub mod mod3 {
+            pub struct TestStruct;
+        }
+    }
+}
 
-            use mod1::mod2;
-            fn main() {
-                mod2::mod3::TestStruct$0
-            }
-            ",
+use mod1::mod2;
+fn main() {
+    mod2::mod3::TestStruct$0
+}
+"#,
         );
     }
 
@@ -459,16 +456,16 @@ fn main() {
     fn not_applicable_for_imported_function() {
         check_assist_not_applicable(
             qualify_path,
-            r"
-            pub mod test_mod {
-                pub fn test_function() {}
-            }
+            r#"
+pub mod test_mod {
+    pub fn test_function() {}
+}
 
-            use test_mod::test_function;
-            fn main() {
-                test_function$0
-            }
-            ",
+use test_mod::test_function;
+fn main() {
+    test_function$0
+}
+"#,
         );
     }
 
@@ -476,30 +473,30 @@ fn main() {
     fn associated_struct_function() {
         check_assist(
             qualify_path,
-            r"
-            mod test_mod {
-                pub struct TestStruct {}
-                impl TestStruct {
-                    pub fn test_function() {}
-                }
-            }
+            r#"
+mod test_mod {
+    pub struct TestStruct {}
+    impl TestStruct {
+        pub fn test_function() {}
+    }
+}
 
-            fn main() {
-                TestStruct::test_function$0
-            }
-            ",
-            r"
-            mod test_mod {
-                pub struct TestStruct {}
-                impl TestStruct {
-                    pub fn test_function() {}
-                }
-            }
+fn main() {
+    TestStruct::test_function$0
+}
+"#,
+            r#"
+mod test_mod {
+    pub struct TestStruct {}
+    impl TestStruct {
+        pub fn test_function() {}
+    }
+}
 
-            fn main() {
-                test_mod::TestStruct::test_function
-            }
-            ",
+fn main() {
+    test_mod::TestStruct::test_function
+}
+"#,
         );
     }
 
@@ -508,62 +505,50 @@ fn main() {
         cov_mark::check!(qualify_path_qualifier_start);
         check_assist(
             qualify_path,
-            r"
-            mod test_mod {
-                pub struct TestStruct {}
-                impl TestStruct {
-                    const TEST_CONST: u8 = 42;
-                }
-            }
+            r#"
+mod test_mod {
+    pub struct TestStruct {}
+    impl TestStruct {
+        const TEST_CONST: u8 = 42;
+    }
+}
 
-            fn main() {
-                TestStruct::TEST_CONST$0
-            }
-            ",
-            r"
-            mod test_mod {
-                pub struct TestStruct {}
-                impl TestStruct {
-                    const TEST_CONST: u8 = 42;
-                }
-            }
+fn main() {
+    TestStruct::TEST_CONST$0
+}
+"#,
+            r#"
+mod test_mod {
+    pub struct TestStruct {}
+    impl TestStruct {
+        const TEST_CONST: u8 = 42;
+    }
+}
 
-            fn main() {
-                test_mod::TestStruct::TEST_CONST
-            }
-            ",
+fn main() {
+    test_mod::TestStruct::TEST_CONST
+}
+"#,
         );
     }
 
     #[test]
-    #[ignore = "FIXME: non-trait assoc items completion is unsupported yet, see FIXME in the import_assets.rs for more details"]
     fn associated_struct_const_unqualified() {
-        check_assist(
+        // FIXME: non-trait assoc items completion is unsupported yet, see FIXME in the import_assets.rs for more details
+        check_assist_not_applicable(
             qualify_path,
-            r"
-            mod test_mod {
-                pub struct TestStruct {}
-                impl TestStruct {
-                    const TEST_CONST: u8 = 42;
-                }
-            }
-
-            fn main() {
-                TEST_CONST$0
-            }
-            ",
-            r"
-            mod test_mod {
-                pub struct TestStruct {}
-                impl TestStruct {
-                    const TEST_CONST: u8 = 42;
-                }
-            }
+            r#"
+mod test_mod {
+    pub struct TestStruct {}
+    impl TestStruct {
+        const TEST_CONST: u8 = 42;
+    }
+}
 
-            fn main() {
-                test_mod::TestStruct::TEST_CONST
-            }
-            ",
+fn main() {
+    TEST_CONST$0
+}
+"#,
         );
     }
 
@@ -571,36 +556,36 @@ fn main() {
     fn associated_trait_function() {
         check_assist(
             qualify_path,
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    fn test_function();
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    fn test_function() {}
-                }
-            }
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        fn test_function();
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        fn test_function() {}
+    }
+}
 
-            fn main() {
-                test_mod::TestStruct::test_function$0
-            }
-            ",
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    fn test_function();
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    fn test_function() {}
-                }
-            }
+fn main() {
+    test_mod::TestStruct::test_function$0
+}
+"#,
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        fn test_function();
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        fn test_function() {}
+    }
+}
 
-            fn main() {
-                <test_mod::TestStruct as test_mod::TestTrait>::test_function
-            }
-            ",
+fn main() {
+    <test_mod::TestStruct as test_mod::TestTrait>::test_function
+}
+"#,
         );
     }
 
@@ -608,31 +593,31 @@ fn main() {
     fn not_applicable_for_imported_trait_for_function() {
         check_assist_not_applicable(
             qualify_path,
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    fn test_function();
-                }
-                pub trait TestTrait2 {
-                    fn test_function();
-                }
-                pub enum TestEnum {
-                    One,
-                    Two,
-                }
-                impl TestTrait2 for TestEnum {
-                    fn test_function() {}
-                }
-                impl TestTrait for TestEnum {
-                    fn test_function() {}
-                }
-            }
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        fn test_function();
+    }
+    pub trait TestTrait2 {
+        fn test_function();
+    }
+    pub enum TestEnum {
+        One,
+        Two,
+    }
+    impl TestTrait2 for TestEnum {
+        fn test_function() {}
+    }
+    impl TestTrait for TestEnum {
+        fn test_function() {}
+    }
+}
 
-            use test_mod::TestTrait2;
-            fn main() {
-                test_mod::TestEnum::test_function$0;
-            }
-            ",
+use test_mod::TestTrait2;
+fn main() {
+    test_mod::TestEnum::test_function$0;
+}
+"#,
         )
     }
 
@@ -641,36 +626,36 @@ fn main() {
         cov_mark::check!(qualify_path_trait_assoc_item);
         check_assist(
             qualify_path,
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    const TEST_CONST: u8;
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    const TEST_CONST: u8 = 42;
-                }
-            }
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        const TEST_CONST: u8;
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        const TEST_CONST: u8 = 42;
+    }
+}
 
-            fn main() {
-                test_mod::TestStruct::TEST_CONST$0
-            }
-            ",
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    const TEST_CONST: u8;
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    const TEST_CONST: u8 = 42;
-                }
-            }
+fn main() {
+    test_mod::TestStruct::TEST_CONST$0
+}
+"#,
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        const TEST_CONST: u8;
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        const TEST_CONST: u8 = 42;
+    }
+}
 
-            fn main() {
-                <test_mod::TestStruct as test_mod::TestTrait>::TEST_CONST
-            }
-            ",
+fn main() {
+    <test_mod::TestStruct as test_mod::TestTrait>::TEST_CONST
+}
+"#,
         );
     }
 
@@ -678,31 +663,31 @@ fn main() {
     fn not_applicable_for_imported_trait_for_const() {
         check_assist_not_applicable(
             qualify_path,
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    const TEST_CONST: u8;
-                }
-                pub trait TestTrait2 {
-                    const TEST_CONST: f64;
-                }
-                pub enum TestEnum {
-                    One,
-                    Two,
-                }
-                impl TestTrait2 for TestEnum {
-                    const TEST_CONST: f64 = 42.0;
-                }
-                impl TestTrait for TestEnum {
-                    const TEST_CONST: u8 = 42;
-                }
-            }
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        const TEST_CONST: u8;
+    }
+    pub trait TestTrait2 {
+        const TEST_CONST: f64;
+    }
+    pub enum TestEnum {
+        One,
+        Two,
+    }
+    impl TestTrait2 for TestEnum {
+        const TEST_CONST: f64 = 42.0;
+    }
+    impl TestTrait for TestEnum {
+        const TEST_CONST: u8 = 42;
+    }
+}
 
-            use test_mod::TestTrait2;
-            fn main() {
-                test_mod::TestEnum::TEST_CONST$0;
-            }
-            ",
+use test_mod::TestTrait2;
+fn main() {
+    test_mod::TestEnum::TEST_CONST$0;
+}
+"#,
         )
     }
 
@@ -711,38 +696,38 @@ fn main() {
         cov_mark::check!(qualify_path_trait_method);
         check_assist(
             qualify_path,
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    fn test_method(&self);
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    fn test_method(&self) {}
-                }
-            }
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        fn test_method(&self);
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        fn test_method(&self) {}
+    }
+}
 
-            fn main() {
-                let test_struct = test_mod::TestStruct {};
-                test_struct.test_meth$0od()
-            }
-            ",
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    fn test_method(&self);
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    fn test_method(&self) {}
-                }
-            }
+fn main() {
+    let test_struct = test_mod::TestStruct {};
+    test_struct.test_meth$0od()
+}
+"#,
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        fn test_method(&self);
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        fn test_method(&self) {}
+    }
+}
 
-            fn main() {
-                let test_struct = test_mod::TestStruct {};
-                test_mod::TestTrait::test_method(&test_struct)
-            }
-            ",
+fn main() {
+    let test_struct = test_mod::TestStruct {};
+    test_mod::TestTrait::test_method(&test_struct)
+}
+"#,
         );
     }
 
@@ -750,38 +735,38 @@ fn main() {
     fn trait_method_multi_params() {
         check_assist(
             qualify_path,
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    fn test_method(&self, test: i32);
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    fn test_method(&self, test: i32) {}
-                }
-            }
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        fn test_method(&self, test: i32);
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        fn test_method(&self, test: i32) {}
+    }
+}
 
-            fn main() {
-                let test_struct = test_mod::TestStruct {};
-                test_struct.test_meth$0od(42)
-            }
-            ",
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    fn test_method(&self, test: i32);
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    fn test_method(&self, test: i32) {}
-                }
-            }
+fn main() {
+    let test_struct = test_mod::TestStruct {};
+    test_struct.test_meth$0od(42)
+}
+"#,
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        fn test_method(&self, test: i32);
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        fn test_method(&self, test: i32) {}
+    }
+}
 
-            fn main() {
-                let test_struct = test_mod::TestStruct {};
-                test_mod::TestTrait::test_method(&test_struct, 42)
-            }
-            ",
+fn main() {
+    let test_struct = test_mod::TestStruct {};
+    test_mod::TestTrait::test_method(&test_struct, 42)
+}
+"#,
         );
     }
 
@@ -789,38 +774,38 @@ fn main() {
     fn trait_method_consume() {
         check_assist(
             qualify_path,
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    fn test_method(self);
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    fn test_method(self) {}
-                }
-            }
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        fn test_method(self);
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        fn test_method(self) {}
+    }
+}
 
-            fn main() {
-                let test_struct = test_mod::TestStruct {};
-                test_struct.test_meth$0od()
-            }
-            ",
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    fn test_method(self);
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    fn test_method(self) {}
-                }
-            }
+fn main() {
+    let test_struct = test_mod::TestStruct {};
+    test_struct.test_meth$0od()
+}
+"#,
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        fn test_method(self);
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        fn test_method(self) {}
+    }
+}
 
-            fn main() {
-                let test_struct = test_mod::TestStruct {};
-                test_mod::TestTrait::test_method(test_struct)
-            }
-            ",
+fn main() {
+    let test_struct = test_mod::TestStruct {};
+    test_mod::TestTrait::test_method(test_struct)
+}
+"#,
         );
     }
 
@@ -828,29 +813,29 @@ fn main() {
     fn trait_method_cross_crate() {
         check_assist(
             qualify_path,
-            r"
-            //- /main.rs crate:main deps:dep
-            fn main() {
-                let test_struct = dep::test_mod::TestStruct {};
-                test_struct.test_meth$0od()
-            }
-            //- /dep.rs crate:dep
-            pub mod test_mod {
-                pub trait TestTrait {
-                    fn test_method(&self);
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    fn test_method(&self) {}
-                }
-            }
-            ",
-            r"
-            fn main() {
-                let test_struct = dep::test_mod::TestStruct {};
-                dep::test_mod::TestTrait::test_method(&test_struct)
-            }
-            ",
+            r#"
+//- /main.rs crate:main deps:dep
+fn main() {
+    let test_struct = dep::test_mod::TestStruct {};
+    test_struct.test_meth$0od()
+}
+//- /dep.rs crate:dep
+pub mod test_mod {
+    pub trait TestTrait {
+        fn test_method(&self);
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        fn test_method(&self) {}
+    }
+}
+"#,
+            r#"
+fn main() {
+    let test_struct = dep::test_mod::TestStruct {};
+    dep::test_mod::TestTrait::test_method(&test_struct)
+}
+"#,
         );
     }
 
@@ -858,27 +843,27 @@ fn main() {
     fn assoc_fn_cross_crate() {
         check_assist(
             qualify_path,
-            r"
-            //- /main.rs crate:main deps:dep
-            fn main() {
-                dep::test_mod::TestStruct::test_func$0tion
-            }
-            //- /dep.rs crate:dep
-            pub mod test_mod {
-                pub trait TestTrait {
-                    fn test_function();
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    fn test_function() {}
-                }
-            }
-            ",
-            r"
-            fn main() {
-                <dep::test_mod::TestStruct as dep::test_mod::TestTrait>::test_function
-            }
-            ",
+            r#"
+//- /main.rs crate:main deps:dep
+fn main() {
+    dep::test_mod::TestStruct::test_func$0tion
+}
+//- /dep.rs crate:dep
+pub mod test_mod {
+    pub trait TestTrait {
+        fn test_function();
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        fn test_function() {}
+    }
+}
+"#,
+            r#"
+fn main() {
+    <dep::test_mod::TestStruct as dep::test_mod::TestTrait>::test_function
+}
+"#,
         );
     }
 
@@ -886,27 +871,27 @@ fn main() {
     fn assoc_const_cross_crate() {
         check_assist(
             qualify_path,
-            r"
-            //- /main.rs crate:main deps:dep
-            fn main() {
-                dep::test_mod::TestStruct::CONST$0
-            }
-            //- /dep.rs crate:dep
-            pub mod test_mod {
-                pub trait TestTrait {
-                    const CONST: bool;
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    const CONST: bool = true;
-                }
-            }
-            ",
-            r"
-            fn main() {
-                <dep::test_mod::TestStruct as dep::test_mod::TestTrait>::CONST
-            }
-            ",
+            r#"
+//- /main.rs crate:main deps:dep
+fn main() {
+    dep::test_mod::TestStruct::CONST$0
+}
+//- /dep.rs crate:dep
+pub mod test_mod {
+    pub trait TestTrait {
+        const CONST: bool;
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        const CONST: bool = true;
+    }
+}
+"#,
+            r#"
+fn main() {
+    <dep::test_mod::TestStruct as dep::test_mod::TestTrait>::CONST
+}
+"#,
         );
     }
 
@@ -914,23 +899,23 @@ fn main() {
     fn assoc_fn_as_method_cross_crate() {
         check_assist_not_applicable(
             qualify_path,
-            r"
-            //- /main.rs crate:main deps:dep
-            fn main() {
-                let test_struct = dep::test_mod::TestStruct {};
-                test_struct.test_func$0tion()
-            }
-            //- /dep.rs crate:dep
-            pub mod test_mod {
-                pub trait TestTrait {
-                    fn test_function();
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    fn test_function() {}
-                }
-            }
-            ",
+            r#"
+//- /main.rs crate:main deps:dep
+fn main() {
+    let test_struct = dep::test_mod::TestStruct {};
+    test_struct.test_func$0tion()
+}
+//- /dep.rs crate:dep
+pub mod test_mod {
+    pub trait TestTrait {
+        fn test_function();
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        fn test_function() {}
+    }
+}
+"#,
         );
     }
 
@@ -938,23 +923,23 @@ fn main() {
     fn private_trait_cross_crate() {
         check_assist_not_applicable(
             qualify_path,
-            r"
-            //- /main.rs crate:main deps:dep
-            fn main() {
-                let test_struct = dep::test_mod::TestStruct {};
-                test_struct.test_meth$0od()
-            }
-            //- /dep.rs crate:dep
-            pub mod test_mod {
-                trait TestTrait {
-                    fn test_method(&self);
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    fn test_method(&self) {}
-                }
-            }
-            ",
+            r#"
+//- /main.rs crate:main deps:dep
+fn main() {
+    let test_struct = dep::test_mod::TestStruct {};
+    test_struct.test_meth$0od()
+}
+//- /dep.rs crate:dep
+pub mod test_mod {
+    trait TestTrait {
+        fn test_method(&self);
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        fn test_method(&self) {}
+    }
+}
+"#,
         );
     }
 
@@ -962,32 +947,32 @@ fn main() {
     fn not_applicable_for_imported_trait_for_method() {
         check_assist_not_applicable(
             qualify_path,
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    fn test_method(&self);
-                }
-                pub trait TestTrait2 {
-                    fn test_method(&self);
-                }
-                pub enum TestEnum {
-                    One,
-                    Two,
-                }
-                impl TestTrait2 for TestEnum {
-                    fn test_method(&self) {}
-                }
-                impl TestTrait for TestEnum {
-                    fn test_method(&self) {}
-                }
-            }
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        fn test_method(&self);
+    }
+    pub trait TestTrait2 {
+        fn test_method(&self);
+    }
+    pub enum TestEnum {
+        One,
+        Two,
+    }
+    impl TestTrait2 for TestEnum {
+        fn test_method(&self) {}
+    }
+    impl TestTrait for TestEnum {
+        fn test_method(&self) {}
+    }
+}
 
-            use test_mod::TestTrait2;
-            fn main() {
-                let one = test_mod::TestEnum::One;
-                one.test$0_method();
-            }
-            ",
+use test_mod::TestTrait2;
+fn main() {
+    let one = test_mod::TestEnum::One;
+    one.test$0_method();
+}
+"#,
         )
     }
 
@@ -1114,7 +1099,7 @@ fn main() {}
     fn keep_generic_annotations_leading_colon() {
         check_assist(
             qualify_path,
-            r"
+            r#"
 //- /lib.rs crate:dep
 pub mod generic { pub struct Thing<'a, T>(&'a T); }
 
@@ -1122,7 +1107,7 @@ pub mod generic { pub struct Thing<'a, T>(&'a T); }
 fn foo() -> Thin$0g::<'static, ()> {}
 
 fn main() {}
-",
+"#,
             r"
 fn foo() -> dep::generic::Thing::<'static, ()> {}
 
@@ -1135,30 +1120,30 @@ fn main() {}
     fn associated_struct_const_generic() {
         check_assist(
             qualify_path,
-            r"
-            mod test_mod {
-                pub struct TestStruct<T> {}
-                impl<T> TestStruct<T> {
-                    const TEST_CONST: u8 = 42;
-                }
-            }
+            r#"
+mod test_mod {
+    pub struct TestStruct<T> {}
+    impl<T> TestStruct<T> {
+        const TEST_CONST: u8 = 42;
+    }
+}
 
-            fn main() {
-                TestStruct::<()>::TEST_CONST$0
-            }
-            ",
-            r"
-            mod test_mod {
-                pub struct TestStruct<T> {}
-                impl<T> TestStruct<T> {
-                    const TEST_CONST: u8 = 42;
-                }
-            }
+fn main() {
+    TestStruct::<()>::TEST_CONST$0
+}
+"#,
+            r#"
+mod test_mod {
+    pub struct TestStruct<T> {}
+    impl<T> TestStruct<T> {
+        const TEST_CONST: u8 = 42;
+    }
+}
 
-            fn main() {
-                test_mod::TestStruct::<()>::TEST_CONST
-            }
-            ",
+fn main() {
+    test_mod::TestStruct::<()>::TEST_CONST
+}
+"#,
         );
     }
 
@@ -1166,36 +1151,36 @@ fn main() {}
     fn associated_trait_const_generic() {
         check_assist(
             qualify_path,
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    const TEST_CONST: u8;
-                }
-                pub struct TestStruct<T> {}
-                impl<T> TestTrait for TestStruct<T> {
-                    const TEST_CONST: u8 = 42;
-                }
-            }
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        const TEST_CONST: u8;
+    }
+    pub struct TestStruct<T> {}
+    impl<T> TestTrait for TestStruct<T> {
+        const TEST_CONST: u8 = 42;
+    }
+}
 
-            fn main() {
-                test_mod::TestStruct::<()>::TEST_CONST$0
-            }
-            ",
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    const TEST_CONST: u8;
-                }
-                pub struct TestStruct<T> {}
-                impl<T> TestTrait for TestStruct<T> {
-                    const TEST_CONST: u8 = 42;
-                }
-            }
+fn main() {
+    test_mod::TestStruct::<()>::TEST_CONST$0
+}
+"#,
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        const TEST_CONST: u8;
+    }
+    pub struct TestStruct<T> {}
+    impl<T> TestTrait for TestStruct<T> {
+        const TEST_CONST: u8 = 42;
+    }
+}
 
-            fn main() {
-                <test_mod::TestStruct::<()> as test_mod::TestTrait>::TEST_CONST
-            }
-            ",
+fn main() {
+    <test_mod::TestStruct::<()> as test_mod::TestTrait>::TEST_CONST
+}
+"#,
         );
     }
 
@@ -1203,38 +1188,38 @@ fn main() {}
     fn trait_method_generic() {
         check_assist(
             qualify_path,
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    fn test_method<T>(&self);
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    fn test_method<T>(&self) {}
-                }
-            }
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        fn test_method<T>(&self);
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        fn test_method<T>(&self) {}
+    }
+}
 
-            fn main() {
-                let test_struct = test_mod::TestStruct {};
-                test_struct.test_meth$0od::<()>()
-            }
-            ",
-            r"
-            mod test_mod {
-                pub trait TestTrait {
-                    fn test_method<T>(&self);
-                }
-                pub struct TestStruct {}
-                impl TestTrait for TestStruct {
-                    fn test_method<T>(&self) {}
-                }
-            }
+fn main() {
+    let test_struct = test_mod::TestStruct {};
+    test_struct.test_meth$0od::<()>()
+}
+"#,
+            r#"
+mod test_mod {
+    pub trait TestTrait {
+        fn test_method<T>(&self);
+    }
+    pub struct TestStruct {}
+    impl TestTrait for TestStruct {
+        fn test_method<T>(&self) {}
+    }
+}
 
-            fn main() {
-                let test_struct = test_mod::TestStruct {};
-                test_mod::TestTrait::test_method::<()>(&test_struct)
-            }
-            ",
+fn main() {
+    let test_struct = test_mod::TestStruct {};
+    test_mod::TestTrait::test_method::<()>(&test_struct)
+}
+"#,
         );
     }
 }
diff --git a/crates/ide_assists/src/handlers/remove_dbg.rs b/crates/ide_assists/src/handlers/remove_dbg.rs
index b20fe992d..5866d8974 100644
--- a/crates/ide_assists/src/handlers/remove_dbg.rs
+++ b/crates/ide_assists/src/handlers/remove_dbg.rs
@@ -35,14 +35,14 @@ pub(crate) fn remove_dbg(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
                             .prev_sibling_or_token()
                             .and_then(whitespace_start)
                             .map(|start| TextRange::new(start, macro_call.syntax().text_range().end()))
-                            .unwrap_or(macro_call.syntax().text_range())
+                            .unwrap_or_else(|| macro_call.syntax().text_range())
                     },
                     ast::ExprStmt(it) => {
                         let start = it
                             .syntax()
                             .prev_sibling_or_token()
                             .and_then(whitespace_start)
-                            .unwrap_or(it.syntax().text_range().start());
+                            .unwrap_or_else(|| it.syntax().text_range().start());
                         let end = it.syntax().text_range().end();
 
                         TextRange::new(start, end)
diff --git a/crates/ide_assists/src/handlers/replace_for_loop_with_for_each.rs b/crates/ide_assists/src/handlers/replace_for_loop_with_for_each.rs
index 50b05ab0b..5f2aa016f 100644
--- a/crates/ide_assists/src/handlers/replace_for_loop_with_for_each.rs
+++ b/crates/ide_assists/src/handlers/replace_for_loop_with_for_each.rs
@@ -85,38 +85,48 @@ fn is_ref_and_impls_iter_method(
     let krate = scope.module()?.krate();
     let traits_in_scope = scope.traits_in_scope();
     let iter_trait = FamousDefs(sema, Some(krate)).core_iter_Iterator()?;
-    let has_wanted_method = typ.iterate_method_candidates(
-        sema.db,
-        krate,
-        &traits_in_scope,
-        Some(&wanted_method),
-        |_, func| {
-            if func.ret_type(sema.db).impls_trait(sema.db, iter_trait, &[]) {
-                return Some(());
-            }
-            None
-        },
-    );
-    has_wanted_method.and(Some((expr_behind_ref, wanted_method)))
+
+    let has_wanted_method = typ
+        .iterate_method_candidates(
+            sema.db,
+            krate,
+            &traits_in_scope,
+            Some(&wanted_method),
+            |_, func| {
+                if func.ret_type(sema.db).impls_trait(sema.db, iter_trait, &[]) {
+                    return Some(());
+                }
+                None
+            },
+        )
+        .is_some();
+    if !has_wanted_method {
+        return None;
+    }
+
+    Some((expr_behind_ref, wanted_method))
 }
 
 /// Whether iterable implements core::Iterator
 fn impls_core_iter(sema: &hir::Semantics<ide_db::RootDatabase>, iterable: &ast::Expr) -> bool {
-    let it_typ = if let Some(i) = sema.type_of_expr(iterable) {
-        i
-    } else {
-        return false;
+    let it_typ = match sema.type_of_expr(iterable) {
+        Some(it) => it,
+        None => return false,
     };
-    let module = if let Some(m) = sema.scope(iterable.syntax()).module() {
-        m
-    } else {
-        return false;
+
+    let module = match sema.scope(iterable.syntax()).module() {
+        Some(it) => it,
+        None => return false,
     };
+
     let krate = module.krate();
-    if let Some(iter_trait) = FamousDefs(sema, Some(krate)).core_iter_Iterator() {
-        return it_typ.impls_trait(sema.db, iter_trait, &[]);
+    match FamousDefs(sema, Some(krate)).core_iter_Iterator() {
+        Some(iter_trait) => {
+            cov_mark::hit!(test_already_impls_iterator);
+            it_typ.impls_trait(sema.db, iter_trait, &[])
+        }
+        None => false,
     }
-    false
 }
 
 #[cfg(test)]
@@ -125,33 +135,6 @@ mod tests {
 
     use super::*;
 
-    const EMPTY_ITER_FIXTURE: &'static str = r"
-//- /lib.rs deps:core crate:empty_iter
-pub struct EmptyIter;
-impl Iterator for EmptyIter {
-    type Item = usize;
-    fn next(&mut self) -> Option<Self::Item> { None }
-}
-
-pub struct Empty;
-impl Empty {
-    pub fn iter(&self) -> EmptyIter { EmptyIter }
-    pub fn iter_mut(&self) -> EmptyIter { EmptyIter }
-}
-
-pub struct NoIterMethod;
-";
-
-    fn check_assist_with_fixtures(before: &str, after: &str) {
-        let before = &format!(
-            "//- /main.rs crate:main deps:core,empty_iter{}{}{}",
-            before,
-            FamousDefs::FIXTURE,
-            EMPTY_ITER_FIXTURE
-        );
-        check_assist(replace_for_loop_with_for_each, before, after);
-    }
-
     #[test]
     fn test_not_for() {
         check_assist_not_applicable(
@@ -201,33 +184,50 @@ fn main() {
 
     #[test]
     fn test_for_borrowed() {
-        check_assist_with_fixtures(
-            r"
-use empty_iter::*;
+        check_assist(
+            replace_for_loop_with_for_each,
+            r#"
+//- minicore: iterators
+use core::iter::{Repeat, repeat};
+
+struct S;
+impl S {
+    fn iter(&self) -> Repeat<i32> { repeat(92) }
+    fn iter_mut(&mut self) -> Repeat<i32> { repeat(92) }
+}
+
 fn main() {
-    let x = Empty;
+    let x = S;
     for $0v in &x {
         let a = v * 2;
     }
 }
-",
-            r"
-use empty_iter::*;
+"#,
+            r#"
+use core::iter::{Repeat, repeat};
+
+struct S;
+impl S {
+    fn iter(&self) -> Repeat<i32> { repeat(92) }
+    fn iter_mut(&mut self) -> Repeat<i32> { repeat(92) }
+}
+
 fn main() {
-    let x = Empty;
+    let x = S;
     x.iter().for_each(|v| {
         let a = v * 2;
     });
 }
-",
+"#,
         )
     }
 
     #[test]
     fn test_for_borrowed_no_iter_method() {
-        check_assist_with_fixtures(
+        check_assist(
+            replace_for_loop_with_for_each,
             r"
-use empty_iter::*;
+struct NoIterMethod;
 fn main() {
     let x = NoIterMethod;
     for $0v in &x {
@@ -236,7 +236,7 @@ fn main() {
 }
 ",
             r"
-use empty_iter::*;
+struct NoIterMethod;
 fn main() {
     let x = NoIterMethod;
     (&x).into_iter().for_each(|v| {
@@ -249,25 +249,41 @@ fn main() {
 
     #[test]
     fn test_for_borrowed_mut() {
-        check_assist_with_fixtures(
-            r"
-use empty_iter::*;
+        check_assist(
+            replace_for_loop_with_for_each,
+            r#"
+//- minicore: iterators
+use core::iter::{Repeat, repeat};
+
+struct S;
+impl S {
+    fn iter(&self) -> Repeat<i32> { repeat(92) }
+    fn iter_mut(&mut self) -> Repeat<i32> { repeat(92) }
+}
+
 fn main() {
-    let x = Empty;
+    let x = S;
     for $0v in &mut x {
         let a = v * 2;
     }
 }
-",
-            r"
-use empty_iter::*;
+"#,
+            r#"
+use core::iter::{Repeat, repeat};
+
+struct S;
+impl S {
+    fn iter(&self) -> Repeat<i32> { repeat(92) }
+    fn iter_mut(&mut self) -> Repeat<i32> { repeat(92) }
+}
+
 fn main() {
-    let x = Empty;
+    let x = S;
     x.iter_mut().for_each(|v| {
         let a = v * 2;
     });
 }
-",
+"#,
         )
     }
 
@@ -296,21 +312,20 @@ fn main() {
 
     #[test]
     fn test_already_impls_iterator() {
-        check_assist_with_fixtures(
+        cov_mark::check!(test_already_impls_iterator);
+        check_assist(
+            replace_for_loop_with_for_each,
             r#"
-use empty_iter::*;
+//- minicore: iterators
 fn main() {
-    let x = Empty;
-    for$0 a in x.iter().take(1) {
+    for$0 a in core::iter::repeat(92).take(1) {
         println!("{}", a);
     }
 }
 "#,
             r#"
-use empty_iter::*;
 fn main() {
-    let x = Empty;
-    x.iter().take(1).for_each(|a| {
+    core::iter::repeat(92).take(1).for_each(|a| {
         println!("{}", a);
     });
 }
diff --git a/crates/ide_assists/src/handlers/replace_if_let_with_match.rs b/crates/ide_assists/src/handlers/replace_if_let_with_match.rs
index 9404aa26d..f37aa0d53 100644
--- a/crates/ide_assists/src/handlers/replace_if_let_with_match.rs
+++ b/crates/ide_assists/src/handlers/replace_if_let_with_match.rs
@@ -262,9 +262,7 @@ impl VariantData {
         check_assist(
             replace_if_let_with_match,
             r#"
-enum Option<T> { Some(T), None }
-use Option::*;
-
+//- minicore: option
 fn foo(x: Option<i32>) {
     $0if let Some(x) = x {
         println!("{}", x)
@@ -272,18 +270,15 @@ fn foo(x: Option<i32>) {
         println!("none")
     }
 }
-           "#,
+"#,
             r#"
-enum Option<T> { Some(T), None }
-use Option::*;
-
 fn foo(x: Option<i32>) {
     match x {
         Some(x) => println!("{}", x),
         None => println!("none"),
     }
 }
-           "#,
+"#,
         );
     }
 
@@ -292,9 +287,7 @@ fn foo(x: Option<i32>) {
         check_assist(
             replace_if_let_with_match,
             r#"
-enum Option<T> { Some(T), None }
-use Option::*;
-
+//- minicore: option
 fn foo(x: Option<i32>) {
     $0if let None = x {
         println!("none")
@@ -302,18 +295,15 @@ fn foo(x: Option<i32>) {
         println!("some")
     }
 }
-           "#,
+"#,
             r#"
-enum Option<T> { Some(T), None }
-use Option::*;
-
 fn foo(x: Option<i32>) {
     match x {
         None => println!("none"),
         Some(_) => println!("some"),
     }
 }
-           "#,
+"#,
         );
     }
 
@@ -322,9 +312,7 @@ fn foo(x: Option<i32>) {
         check_assist(
             replace_if_let_with_match,
             r#"
-enum Result<T, E> { Ok(T), Err(E) }
-use Result::*;
-
+//- minicore: result
 fn foo(x: Result<i32, ()>) {
     $0if let Ok(x) = x {
         println!("{}", x)
@@ -332,18 +320,15 @@ fn foo(x: Result<i32, ()>) {
         println!("none")
     }
 }
-           "#,
+"#,
             r#"
-enum Result<T, E> { Ok(T), Err(E) }
-use Result::*;
-
 fn foo(x: Result<i32, ()>) {
     match x {
         Ok(x) => println!("{}", x),
         Err(_) => println!("none"),
     }
 }
-           "#,
+"#,
         );
     }
 
@@ -352,9 +337,7 @@ fn foo(x: Result<i32, ()>) {
         check_assist(
             replace_if_let_with_match,
             r#"
-enum Result<T, E> { Ok(T), Err(E) }
-use Result::*;
-
+//- minicore: result
 fn foo(x: Result<i32, ()>) {
     $0if let Err(x) = x {
         println!("{}", x)
@@ -362,18 +345,15 @@ fn foo(x: Result<i32, ()>) {
         println!("ok")
     }
 }
-           "#,
+"#,
             r#"
-enum Result<T, E> { Ok(T), Err(E) }
-use Result::*;
-
 fn foo(x: Result<i32, ()>) {
     match x {
         Err(x) => println!("{}", x),
         Ok(_) => println!("ok"),
     }
 }
-           "#,
+"#,
         );
     }
 
@@ -488,20 +468,15 @@ impl VariantData {
         check_assist(
             replace_match_with_if_let,
             r#"
-enum Option<T> { Some(T), None }
-use Option::*;
-
+//- minicore: option
 fn foo(x: Option<i32>) {
     $0match x {
         Some(x) => println!("{}", x),
         None => println!("none"),
     }
 }
-           "#,
+"#,
             r#"
-enum Option<T> { Some(T), None }
-use Option::*;
-
 fn foo(x: Option<i32>) {
     if let Some(x) = x {
         println!("{}", x)
@@ -509,7 +484,7 @@ fn foo(x: Option<i32>) {
         println!("none")
     }
 }
-           "#,
+"#,
         );
     }
 
@@ -518,20 +493,15 @@ fn foo(x: Option<i32>) {
         check_assist(
             replace_match_with_if_let,
             r#"
-enum Result<T, E> { Ok(T), Err(E) }
-use Result::*;
-
+//- minicore: result
 fn foo(x: Result<i32, ()>) {
     $0match x {
         Ok(x) => println!("{}", x),
         Err(_) => println!("none"),
     }
 }
-           "#,
+"#,
             r#"
-enum Result<T, E> { Ok(T), Err(E) }
-use Result::*;
-
 fn foo(x: Result<i32, ()>) {
     if let Ok(x) = x {
         println!("{}", x)
@@ -539,7 +509,7 @@ fn foo(x: Result<i32, ()>) {
         println!("none")
     }
 }
-           "#,
+"#,
         );
     }
 
diff --git a/crates/ide_assists/src/handlers/replace_impl_trait_with_generic.rs b/crates/ide_assists/src/handlers/replace_impl_trait_with_generic.rs
index 540a905cc..a2af2035f 100644
--- a/crates/ide_assists/src/handlers/replace_impl_trait_with_generic.rs
+++ b/crates/ide_assists/src/handlers/replace_impl_trait_with_generic.rs
@@ -105,12 +105,13 @@ fn foo<B: Bar
     }
 
     #[test]
-    #[ignore = "This case is very rare but there is no simple solutions to fix it."]
     fn replace_impl_trait_with_exist_generic_letter() {
+        // FIXME: This is wrong, we should pick a different name if the one we
+        // want is already bound.
         check_assist(
             replace_impl_trait_with_generic,
             r#"fn foo<B>(bar: $0impl Bar) {}"#,
-            r#"fn foo<B, C: Bar>(bar: C) {}"#,
+            r#"fn foo<B, B: Bar>(bar: B) {}"#,
         );
     }
 
diff --git a/crates/ide_assists/src/handlers/replace_qualified_name_with_use.rs b/crates/ide_assists/src/handlers/replace_qualified_name_with_use.rs
index 39f5eb4ff..26778ee74 100644
--- a/crates/ide_assists/src/handlers/replace_qualified_name_with_use.rs
+++ b/crates/ide_assists/src/handlers/replace_qualified_name_with_use.rs
@@ -32,7 +32,6 @@ pub(crate) fn replace_qualified_name_with_use(
 
     let target = path.syntax().text_range();
     let scope = ImportScope::find_insert_use_container_with_macros(path.syntax(), &ctx.sema)?;
-    let syntax = scope.as_syntax_node();
     acc.add(
         AssistId("replace_qualified_name_with_use", AssistKind::RefactorRewrite),
         "Replace qualified path with use",
@@ -40,11 +39,13 @@ pub(crate) fn replace_qualified_name_with_use(
         |builder| {
             // Now that we've brought the name into scope, re-qualify all paths that could be
             // affected (that is, all paths inside the node we added the `use` to).
-            let syntax = builder.make_syntax_mut(syntax.clone());
-            if let Some(ref import_scope) = ImportScope::from(syntax.clone()) {
-                shorten_paths(&syntax, &path.clone_for_update());
-                insert_use(import_scope, path, ctx.config.insert_use);
-            }
+            let scope = match scope {
+                ImportScope::File(it) => ImportScope::File(builder.make_mut(it)),
+                ImportScope::Module(it) => ImportScope::Module(builder.make_mut(it)),
+                ImportScope::Block(it) => ImportScope::Block(builder.make_mut(it)),
+            };
+            shorten_paths(scope.as_syntax_node(), &path.clone_for_update());
+            insert_use(&scope, path, &ctx.config.insert_use);
         },
     )
 }
diff --git a/crates/ide_assists/src/handlers/replace_unwrap_with_match.rs b/crates/ide_assists/src/handlers/replace_unwrap_with_match.rs
index a3bfa221c..f39c48d8f 100644
--- a/crates/ide_assists/src/handlers/replace_unwrap_with_match.rs
+++ b/crates/ide_assists/src/handlers/replace_unwrap_with_match.rs
@@ -20,17 +20,16 @@ use ide_db::ty_filter::TryEnum;
 // Replaces `unwrap` with a `match` expression. Works for Result and Option.
 //
 // ```
-// enum Result<T, E> { Ok(T), Err(E) }
+// # //- minicore: result
 // fn main() {
-//     let x: Result<i32, i32> = Result::Ok(92);
+//     let x: Result<i32, i32> = Ok(92);
 //     let y = x.$0unwrap();
 // }
 // ```
 // ->
 // ```
-// enum Result<T, E> { Ok(T), Err(E) }
 // fn main() {
-//     let x: Result<i32, i32> = Result::Ok(92);
+//     let x: Result<i32, i32> = Ok(92);
 //     let y = match x {
 //         Ok(it) => it,
 //         $0_ => unreachable!(),
@@ -97,25 +96,24 @@ mod tests {
     fn test_replace_result_unwrap_with_match() {
         check_assist(
             replace_unwrap_with_match,
-            r"
-enum Result<T, E> { Ok(T), Err(E) }
+            r#"
+//- minicore: result
 fn i<T>(a: T) -> T { a }
 fn main() {
-    let x: Result<i32, i32> = Result::Ok(92);
+    let x: Result<i32, i32> = Ok(92);
     let y = i(x).$0unwrap();
 }
-            ",
-            r"
-enum Result<T, E> { Ok(T), Err(E) }
+"#,
+            r#"
 fn i<T>(a: T) -> T { a }
 fn main() {
-    let x: Result<i32, i32> = Result::Ok(92);
+    let x: Result<i32, i32> = Ok(92);
     let y = match i(x) {
         Ok(it) => it,
         $0_ => unreachable!(),
     };
 }
-            ",
+"#,
         )
     }
 
@@ -123,25 +121,24 @@ fn main() {
     fn test_replace_option_unwrap_with_match() {
         check_assist(
             replace_unwrap_with_match,
-            r"
-enum Option<T> { Some(T), None }
+            r#"
+//- minicore: option
 fn i<T>(a: T) -> T { a }
 fn main() {
-    let x = Option::Some(92);
+    let x = Some(92);
     let y = i(x).$0unwrap();
 }
-            ",
-            r"
-enum Option<T> { Some(T), None }
+"#,
+            r#"
 fn i<T>(a: T) -> T { a }
 fn main() {
-    let x = Option::Some(92);
+    let x = Some(92);
     let y = match i(x) {
         Some(it) => it,
         $0_ => unreachable!(),
     };
 }
-            ",
+"#,
         );
     }
 
@@ -149,25 +146,24 @@ fn main() {
     fn test_replace_result_unwrap_with_match_chaining() {
         check_assist(
             replace_unwrap_with_match,
-            r"
-enum Result<T, E> { Ok(T), Err(E) }
+            r#"
+//- minicore: result
 fn i<T>(a: T) -> T { a }
 fn main() {
-    let x: Result<i32, i32> = Result::Ok(92);
+    let x: Result<i32, i32> = Ok(92);
     let y = i(x).$0unwrap().count_zeroes();
 }
-            ",
-            r"
-enum Result<T, E> { Ok(T), Err(E) }
+"#,
+            r#"
 fn i<T>(a: T) -> T { a }
 fn main() {
-    let x: Result<i32, i32> = Result::Ok(92);
+    let x: Result<i32, i32> = Ok(92);
     let y = match i(x) {
         Ok(it) => it,
         $0_ => unreachable!(),
     }.count_zeroes();
 }
-            ",
+"#,
         )
     }
 
@@ -175,14 +171,14 @@ fn main() {
     fn replace_unwrap_with_match_target() {
         check_assist_target(
             replace_unwrap_with_match,
-            r"
-enum Option<T> { Some(T), None }
+            r#"
+//- minicore: option
 fn i<T>(a: T) -> T { a }
 fn main() {
-    let x = Option::Some(92);
+    let x = Some(92);
     let y = i(x).$0unwrap();
 }
-            ",
+"#,
             r"i(x).unwrap()",
         );
     }
diff --git a/crates/ide_assists/src/handlers/unmerge_use.rs b/crates/ide_assists/src/handlers/unmerge_use.rs
index 8d271e056..14e862cd0 100644
--- a/crates/ide_assists/src/handlers/unmerge_use.rs
+++ b/crates/ide_assists/src/handlers/unmerge_use.rs
@@ -73,7 +73,11 @@ fn resolve_full_path(tree: &ast::UseTree) -> Option<ast::Path> {
     for path in paths {
         final_path = ast::make::path_concat(path, final_path)
     }
-    Some(final_path)
+    if final_path.segment().map_or(false, |it| it.self_token().is_some()) {
+        final_path.qualifier()
+    } else {
+        Some(final_path)
+    }
 }
 
 #[cfg(test)]
@@ -223,4 +227,14 @@ pub use std::fmt::Display;
 ",
         );
     }
+
+    #[test]
+    fn unmerge_use_item_on_self() {
+        check_assist(
+            unmerge_use,
+            r"use std::process::{Command, self$0};",
+            r"use std::process::{Command};
+use std::process;",
+        );
+    }
 }
diff --git a/crates/ide_assists/src/lib.rs b/crates/ide_assists/src/lib.rs
index 331a6df2b..86a57ce5d 100644
--- a/crates/ide_assists/src/lib.rs
+++ b/crates/ide_assists/src/lib.rs
@@ -15,158 +15,32 @@ mod assist_context;
 #[cfg(test)]
 mod tests;
 pub mod utils;
-pub mod path_transform;
-
-use std::str::FromStr;
 
 use hir::Semantics;
-use ide_db::{base_db::FileRange, label::Label, source_change::SourceChange, RootDatabase};
+use ide_db::{base_db::FileRange, RootDatabase};
 use syntax::TextRange;
 
 pub(crate) use crate::assist_context::{AssistContext, Assists};
 
 pub use assist_config::AssistConfig;
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum AssistKind {
-    // FIXME: does the None variant make sense? Probably not.
-    None,
-
-    QuickFix,
-    Generate,
-    Refactor,
-    RefactorExtract,
-    RefactorInline,
-    RefactorRewrite,
-}
-
-impl AssistKind {
-    pub fn contains(self, other: AssistKind) -> bool {
-        if self == other {
-            return true;
-        }
-
-        match self {
-            AssistKind::None | AssistKind::Generate => true,
-            AssistKind::Refactor => match other {
-                AssistKind::RefactorExtract
-                | AssistKind::RefactorInline
-                | AssistKind::RefactorRewrite => true,
-                _ => false,
-            },
-            _ => false,
-        }
-    }
-
-    pub fn name(&self) -> &str {
-        match self {
-            AssistKind::None => "None",
-            AssistKind::QuickFix => "QuickFix",
-            AssistKind::Generate => "Generate",
-            AssistKind::Refactor => "Refactor",
-            AssistKind::RefactorExtract => "RefactorExtract",
-            AssistKind::RefactorInline => "RefactorInline",
-            AssistKind::RefactorRewrite => "RefactorRewrite",
-        }
-    }
-}
-
-impl FromStr for AssistKind {
-    type Err = String;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        match s {
-            "None" => Ok(AssistKind::None),
-            "QuickFix" => Ok(AssistKind::QuickFix),
-            "Generate" => Ok(AssistKind::Generate),
-            "Refactor" => Ok(AssistKind::Refactor),
-            "RefactorExtract" => Ok(AssistKind::RefactorExtract),
-            "RefactorInline" => Ok(AssistKind::RefactorInline),
-            "RefactorRewrite" => Ok(AssistKind::RefactorRewrite),
-            unknown => Err(format!("Unknown AssistKind: '{}'", unknown)),
-        }
-    }
-}
-
-/// Unique identifier of the assist, should not be shown to the user
-/// directly.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub struct AssistId(pub &'static str, pub AssistKind);
-
-/// A way to control how many asssist to resolve during the assist resolution.
-/// When an assist is resolved, its edits are calculated that might be costly to always do by default.
-#[derive(Debug)]
-pub enum AssistResolveStrategy {
-    /// No assists should be resolved.
-    None,
-    /// All assists should be resolved.
-    All,
-    /// Only a certain assist should be resolved.
-    Single(SingleResolve),
-}
-
-/// Hold the [`AssistId`] data of a certain assist to resolve.
-/// The original id object cannot be used due to a `'static` lifetime
-/// and the requirement to construct this struct dynamically during the resolve handling.
-#[derive(Debug)]
-pub struct SingleResolve {
-    /// The id of the assist.
-    pub assist_id: String,
-    // The kind of the assist.
-    pub assist_kind: AssistKind,
-}
-
-impl AssistResolveStrategy {
-    pub fn should_resolve(&self, id: &AssistId) -> bool {
-        match self {
-            AssistResolveStrategy::None => false,
-            AssistResolveStrategy::All => true,
-            AssistResolveStrategy::Single(single_resolve) => {
-                single_resolve.assist_id == id.0 && single_resolve.assist_kind == id.1
-            }
-        }
-    }
-}
-
-#[derive(Clone, Debug)]
-pub struct GroupLabel(pub String);
-
-#[derive(Debug, Clone)]
-pub struct Assist {
-    pub id: AssistId,
-    /// Short description of the assist, as shown in the UI.
-    pub label: Label,
-    pub group: Option<GroupLabel>,
-    /// Target ranges are used to sort assists: the smaller the target range,
-    /// the more specific assist is, and so it should be sorted first.
-    pub target: TextRange,
-    /// Computing source change sometimes is much more costly then computing the
-    /// other fields. Additionally, the actual change is not required to show
-    /// the lightbulb UI, it only is needed when the user tries to apply an
-    /// assist. So, we compute it lazily: the API allow requesting assists with
-    /// or without source change. We could (and in fact, used to) distinguish
-    /// between resolved and unresolved assists at the type level, but this is
-    /// cumbersome, especially if you want to embed an assist into another data
-    /// structure, such as a diagnostic.
-    pub source_change: Option<SourceChange>,
-}
-
-impl Assist {
-    /// Return all the assists applicable at the given position.
-    pub fn get(
-        db: &RootDatabase,
-        config: &AssistConfig,
-        resolve: AssistResolveStrategy,
-        range: FileRange,
-    ) -> Vec<Assist> {
-        let sema = Semantics::new(db);
-        let ctx = AssistContext::new(sema, config, range);
-        let mut acc = Assists::new(&ctx, resolve);
-        handlers::all().iter().for_each(|handler| {
-            handler(&mut acc, &ctx);
-        });
-        acc.finish()
-    }
+pub use ide_db::assists::{
+    Assist, AssistId, AssistKind, AssistResolveStrategy, GroupLabel, SingleResolve,
+};
+
+/// Return all the assists applicable at the given position.
+pub fn assists(
+    db: &RootDatabase,
+    config: &AssistConfig,
+    resolve: AssistResolveStrategy,
+    range: FileRange,
+) -> Vec<Assist> {
+    let sema = Semantics::new(db);
+    let ctx = AssistContext::new(sema, config, range);
+    let mut acc = Assists::new(&ctx, resolve);
+    handlers::all().iter().for_each(|handler| {
+        handler(&mut acc, &ctx);
+    });
+    acc.finish()
 }
 
 mod handlers {
diff --git a/crates/ide_assists/src/tests.rs b/crates/ide_assists/src/tests.rs
index bdf9cb71c..841537c77 100644
--- a/crates/ide_assists/src/tests.rs
+++ b/crates/ide_assists/src/tests.rs
@@ -16,8 +16,8 @@ use syntax::TextRange;
 use test_utils::{assert_eq_text, extract_offset};
 
 use crate::{
-    handlers::Handler, Assist, AssistConfig, AssistContext, AssistKind, AssistResolveStrategy,
-    Assists, SingleResolve,
+    assists, handlers::Handler, Assist, AssistConfig, AssistContext, AssistKind,
+    AssistResolveStrategy, Assists, SingleResolve,
 };
 
 pub(crate) const TEST_CONFIG: AssistConfig = AssistConfig {
@@ -28,6 +28,7 @@ pub(crate) const TEST_CONFIG: AssistConfig = AssistConfig {
         prefix_kind: hir::PrefixKind::Plain,
         enforce_granularity: true,
         group: true,
+        skip_glob_imports: true,
     },
 };
 
@@ -35,6 +36,7 @@ pub(crate) fn with_single_file(text: &str) -> (RootDatabase, FileId) {
     RootDatabase::with_single_file(text)
 }
 
+#[track_caller]
 pub(crate) fn check_assist(assist: Handler, ra_fixture_before: &str, ra_fixture_after: &str) {
     let ra_fixture_after = trim_indent(ra_fixture_after);
     check(assist, ra_fixture_before, ExpectedResult::After(&ra_fixture_after), None);
@@ -78,14 +80,14 @@ fn check_doc_test(assist_id: &str, before: &str, after: &str) {
     let before = db.file_text(file_id).to_string();
     let frange = FileRange { file_id, range: selection.into() };
 
-    let assist = Assist::get(&db, &TEST_CONFIG, AssistResolveStrategy::All, frange)
+    let assist = assists(&db, &TEST_CONFIG, AssistResolveStrategy::All, frange)
         .into_iter()
         .find(|assist| assist.id.0 == assist_id)
         .unwrap_or_else(|| {
             panic!(
                 "\n\nAssist is not applicable: {}\nAvailable assists: {}",
                 assist_id,
-                Assist::get(&db, &TEST_CONFIG, AssistResolveStrategy::None, frange)
+                assists(&db, &TEST_CONFIG, AssistResolveStrategy::None, frange)
                     .into_iter()
                     .map(|assist| assist.id.0)
                     .collect::<Vec<_>>()
@@ -179,9 +181,10 @@ fn check(handler: Handler, before: &str, expected: ExpectedResult, assist_label:
             "unresolved assist should not contain source changes"
         ),
         (Some(_), ExpectedResult::NotApplicable) => panic!("assist should not be applicable!"),
-        (None, ExpectedResult::After(_))
-        | (None, ExpectedResult::Target(_))
-        | (None, ExpectedResult::Unresolved) => {
+        (
+            None,
+            ExpectedResult::After(_) | ExpectedResult::Target(_) | ExpectedResult::Unresolved,
+        ) => {
             panic!("code action is not applicable")
         }
         (None, ExpectedResult::NotApplicable) => (),
@@ -210,7 +213,7 @@ fn assist_order_field_struct() {
     let (before_cursor_pos, before) = extract_offset(before);
     let (db, file_id) = with_single_file(&before);
     let frange = FileRange { file_id, range: TextRange::empty(before_cursor_pos) };
-    let assists = Assist::get(&db, &TEST_CONFIG, AssistResolveStrategy::None, frange);
+    let assists = assists(&db, &TEST_CONFIG, AssistResolveStrategy::None, frange);
     let mut assists = assists.iter();
 
     assert_eq!(assists.next().expect("expected assist").label, "Change visibility to pub(crate)");
@@ -235,7 +238,7 @@ pub fn test_some_range(a: int) -> bool {
 "#,
     );
 
-    let assists = Assist::get(&db, &TEST_CONFIG, AssistResolveStrategy::None, frange);
+    let assists = assists(&db, &TEST_CONFIG, AssistResolveStrategy::None, frange);
     let expected = labels(&assists);
 
     expect![[r#"
@@ -264,7 +267,7 @@ pub fn test_some_range(a: int) -> bool {
         let mut cfg = TEST_CONFIG;
         cfg.allowed = Some(vec![AssistKind::Refactor]);
 
-        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::None, frange);
+        let assists = assists(&db, &cfg, AssistResolveStrategy::None, frange);
         let expected = labels(&assists);
 
         expect![[r#"
@@ -279,7 +282,7 @@ pub fn test_some_range(a: int) -> bool {
     {
         let mut cfg = TEST_CONFIG;
         cfg.allowed = Some(vec![AssistKind::RefactorExtract]);
-        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::None, frange);
+        let assists = assists(&db, &cfg, AssistResolveStrategy::None, frange);
         let expected = labels(&assists);
 
         expect![[r#"
@@ -292,7 +295,7 @@ pub fn test_some_range(a: int) -> bool {
     {
         let mut cfg = TEST_CONFIG;
         cfg.allowed = Some(vec![AssistKind::QuickFix]);
-        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::None, frange);
+        let assists = assists(&db, &cfg, AssistResolveStrategy::None, frange);
         let expected = labels(&assists);
 
         expect![[r#""#]].assert_eq(&expected);
@@ -317,7 +320,7 @@ pub fn test_some_range(a: int) -> bool {
     cfg.allowed = Some(vec![AssistKind::RefactorExtract]);
 
     {
-        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::None, frange);
+        let assists = assists(&db, &cfg, AssistResolveStrategy::None, frange);
         assert_eq!(2, assists.len());
         let mut assists = assists.into_iter();
 
@@ -353,7 +356,7 @@ pub fn test_some_range(a: int) -> bool {
     }
 
     {
-        let assists = Assist::get(
+        let assists = assists(
             &db,
             &cfg,
             AssistResolveStrategy::Single(SingleResolve {
@@ -397,7 +400,7 @@ pub fn test_some_range(a: int) -> bool {
     }
 
     {
-        let assists = Assist::get(
+        let assists = assists(
             &db,
             &cfg,
             AssistResolveStrategy::Single(SingleResolve {
@@ -462,7 +465,7 @@ pub fn test_some_range(a: int) -> bool {
     }
 
     {
-        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::All, frange);
+        let assists = assists(&db, &cfg, AssistResolveStrategy::All, frange);
         assert_eq!(2, assists.len());
         let mut assists = assists.into_iter();
 
diff --git a/crates/ide_assists/src/tests/generated.rs b/crates/ide_assists/src/tests/generated.rs
index de5d9e55a..1509c3c63 100644
--- a/crates/ide_assists/src/tests/generated.rs
+++ b/crates/ide_assists/src/tests/generated.rs
@@ -209,10 +209,7 @@ fn doctest_convert_into_to_from() {
     check_doc_test(
         "convert_into_to_from",
         r#####"
-//- /lib.rs crate:core
-pub mod convert { pub trait Into<T> { pub fn into(self) -> T; } }
-//- /lib.rs crate:main deps:core
-use core::convert::Into;
+//- minicore: from
 impl $0Into<Thing> for usize {
     fn into(self) -> Thing {
         Thing {
@@ -223,7 +220,6 @@ impl $0Into<Thing> for usize {
 }
 "#####,
         r#####"
-use core::convert::Into;
 impl From<usize> for Thing {
     fn from(val: usize) -> Self {
         Thing {
@@ -241,23 +237,19 @@ fn doctest_convert_iter_for_each_to_for() {
     check_doc_test(
         "convert_iter_for_each_to_for",
         r#####"
-//- /lib.rs crate:core
-pub mod iter { pub mod traits { pub mod iterator { pub trait Iterator {} } } }
-pub struct SomeIter;
-impl self::iter::traits::iterator::Iterator for SomeIter {}
-//- /lib.rs crate:main deps:core
-use core::SomeIter;
+//- minicore: iterators
+use core::iter;
 fn main() {
-    let iter = SomeIter;
+    let iter = iter::repeat((9, 2));
     iter.for_each$0(|(x, y)| {
         println!("x: {}, y: {}", x, y);
     });
 }
 "#####,
         r#####"
-use core::SomeIter;
+use core::iter;
 fn main() {
-    let iter = SomeIter;
+    let iter = iter::repeat((9, 2));
     for (x, y) in iter {
         println!("x: {}, y: {}", x, y);
     }
@@ -1519,16 +1511,15 @@ fn doctest_replace_unwrap_with_match() {
     check_doc_test(
         "replace_unwrap_with_match",
         r#####"
-enum Result<T, E> { Ok(T), Err(E) }
+//- minicore: result
 fn main() {
-    let x: Result<i32, i32> = Result::Ok(92);
+    let x: Result<i32, i32> = Ok(92);
     let y = x.$0unwrap();
 }
 "#####,
         r#####"
-enum Result<T, E> { Ok(T), Err(E) }
 fn main() {
-    let x: Result<i32, i32> = Result::Ok(92);
+    let x: Result<i32, i32> = Ok(92);
     let y = match x {
         Ok(it) => it,
         $0_ => unreachable!(),
diff --git a/crates/ide_assists/src/utils.rs b/crates/ide_assists/src/utils.rs
index 068df005b..0ec236aa0 100644
--- a/crates/ide_assists/src/utils.rs
+++ b/crates/ide_assists/src/utils.rs
@@ -8,6 +8,7 @@ use ast::TypeBoundsOwner;
 use hir::{Adt, HasSource, Semantics};
 use ide_db::{
     helpers::{FamousDefs, SnippetCap},
+    path_transform::PathTransform,
     RootDatabase,
 };
 use itertools::Itertools;
@@ -22,10 +23,7 @@ use syntax::{
     SyntaxNode, TextSize, T,
 };
 
-use crate::{
-    assist_context::{AssistBuilder, AssistContext},
-    path_transform::PathTransform,
-};
+use crate::assist_context::{AssistBuilder, AssistContext};
 
 pub(crate) fn unwrap_trivial_block(block: ast::BlockExpr) -> ast::Expr {
     extract_trivial_expression(&block)
diff --git a/crates/ide_completion/src/completions.rs b/crates/ide_completion/src/completions.rs
index bd90cefb2..cba5eb0c6 100644
--- a/crates/ide_completion/src/completions.rs
+++ b/crates/ide_completion/src/completions.rs
@@ -41,9 +41,9 @@ pub struct Completions {
     buf: Vec<CompletionItem>,
 }
 
-impl Into<Vec<CompletionItem>> for Completions {
-    fn into(self) -> Vec<CompletionItem> {
-        self.buf
+impl From<Completions> for Vec<CompletionItem> {
+    fn from(val: Completions) -> Self {
+        val.buf
     }
 }
 
@@ -74,44 +74,12 @@ impl Completions {
         items.into_iter().for_each(|item| self.add(item.into()))
     }
 
-    pub(crate) fn add_field(
-        &mut self,
-        ctx: &CompletionContext,
-        receiver: Option<hir::Name>,
-        field: hir::Field,
-        ty: &hir::Type,
-    ) {
-        let item = render_field(RenderContext::new(ctx), receiver, field, ty);
-        self.add(item);
-    }
-
-    pub(crate) fn add_tuple_field(
-        &mut self,
-        ctx: &CompletionContext,
-        receiver: Option<hir::Name>,
-        field: usize,
-        ty: &hir::Type,
-    ) {
-        let item = render_tuple_field(RenderContext::new(ctx), receiver, field, ty);
-        self.add(item);
-    }
-
-    pub(crate) fn add_static_lifetime(&mut self, ctx: &CompletionContext) {
-        let mut item =
-            CompletionItem::new(CompletionKind::Reference, ctx.source_range(), "'static");
-        item.kind(CompletionItemKind::SymbolKind(SymbolKind::LifetimeParam));
-        self.add(item.build());
-    }
-
     pub(crate) fn add_resolution(
         &mut self,
         ctx: &CompletionContext,
         local_name: hir::Name,
         resolution: &hir::ScopeDef,
     ) {
-        if ctx.expects_type() && resolution.is_value_def() {
-            return;
-        }
         self.add_opt(render_resolution(RenderContext::new(ctx), local_name, resolution));
     }
 
@@ -134,9 +102,6 @@ impl Completions {
         func: hir::Function,
         local_name: Option<hir::Name>,
     ) {
-        if ctx.expects_type() {
-            return;
-        }
         self.add_opt(render_fn(RenderContext::new(ctx), None, local_name, func));
     }
 
@@ -150,94 +115,119 @@ impl Completions {
         self.add_opt(render_method(RenderContext::new(ctx), None, receiver, local_name, func));
     }
 
-    pub(crate) fn add_variant_pat(
+    pub(crate) fn add_const(&mut self, ctx: &CompletionContext, constant: hir::Const) {
+        self.add_opt(render_const(RenderContext::new(ctx), constant));
+    }
+
+    pub(crate) fn add_type_alias(&mut self, ctx: &CompletionContext, type_alias: hir::TypeAlias) {
+        self.add_opt(render_type_alias(RenderContext::new(ctx), type_alias));
+    }
+
+    pub(crate) fn add_type_alias_with_eq(
         &mut self,
         ctx: &CompletionContext,
-        variant: hir::Variant,
-        local_name: Option<hir::Name>,
+        type_alias: hir::TypeAlias,
     ) {
-        self.add_opt(render_variant_pat(RenderContext::new(ctx), variant, local_name, None));
+        self.add_opt(render_type_alias_with_eq(RenderContext::new(ctx), type_alias));
     }
 
-    pub(crate) fn add_qualified_variant_pat(
+    pub(crate) fn add_qualified_enum_variant(
         &mut self,
         ctx: &CompletionContext,
         variant: hir::Variant,
         path: hir::ModPath,
     ) {
-        self.add_opt(render_variant_pat(RenderContext::new(ctx), variant, None, Some(path)));
+        let item = render_variant(RenderContext::new(ctx), None, None, variant, Some(path));
+        self.add(item);
     }
 
-    pub(crate) fn add_struct_pat(
+    pub(crate) fn add_enum_variant(
         &mut self,
         ctx: &CompletionContext,
-        strukt: hir::Struct,
+        variant: hir::Variant,
         local_name: Option<hir::Name>,
     ) {
-        self.add_opt(render_struct_pat(RenderContext::new(ctx), strukt, local_name));
+        let item = render_variant(RenderContext::new(ctx), None, local_name, variant, None);
+        self.add(item);
     }
 
-    pub(crate) fn add_const(&mut self, ctx: &CompletionContext, constant: hir::Const) {
-        if ctx.expects_type() {
-            return;
-        }
-        self.add_opt(render_const(RenderContext::new(ctx), constant));
+    pub(crate) fn add_field(
+        &mut self,
+        ctx: &CompletionContext,
+        receiver: Option<hir::Name>,
+        field: hir::Field,
+        ty: &hir::Type,
+    ) {
+        let item = render_field(RenderContext::new(ctx), receiver, field, ty);
+        self.add(item);
     }
 
-    pub(crate) fn add_type_alias(&mut self, ctx: &CompletionContext, type_alias: hir::TypeAlias) {
-        self.add_opt(render_type_alias(RenderContext::new(ctx), type_alias));
+    pub(crate) fn add_tuple_field(
+        &mut self,
+        ctx: &CompletionContext,
+        receiver: Option<hir::Name>,
+        field: usize,
+        ty: &hir::Type,
+    ) {
+        let item = render_tuple_field(RenderContext::new(ctx), receiver, field, ty);
+        self.add(item);
     }
 
-    pub(crate) fn add_type_alias_with_eq(
+    pub(crate) fn add_static_lifetime(&mut self, ctx: &CompletionContext) {
+        let mut item =
+            CompletionItem::new(CompletionKind::Reference, ctx.source_range(), "'static");
+        item.kind(CompletionItemKind::SymbolKind(SymbolKind::LifetimeParam));
+        self.add(item.build());
+    }
+
+    pub(crate) fn add_variant_pat(
         &mut self,
         ctx: &CompletionContext,
-        type_alias: hir::TypeAlias,
+        variant: hir::Variant,
+        local_name: Option<hir::Name>,
     ) {
-        self.add_opt(render_type_alias_with_eq(RenderContext::new(ctx), type_alias));
+        self.add_opt(render_variant_pat(RenderContext::new(ctx), variant, local_name, None));
     }
 
-    pub(crate) fn add_qualified_enum_variant(
+    pub(crate) fn add_qualified_variant_pat(
         &mut self,
         ctx: &CompletionContext,
         variant: hir::Variant,
         path: hir::ModPath,
     ) {
-        let item = render_variant(RenderContext::new(ctx), None, None, variant, Some(path));
-        self.add(item);
+        self.add_opt(render_variant_pat(RenderContext::new(ctx), variant, None, Some(path)));
     }
 
-    pub(crate) fn add_enum_variant(
+    pub(crate) fn add_struct_pat(
         &mut self,
         ctx: &CompletionContext,
-        variant: hir::Variant,
+        strukt: hir::Struct,
         local_name: Option<hir::Name>,
     ) {
-        if ctx.expects_type() {
-            return;
-        }
-        let item = render_variant(RenderContext::new(ctx), None, local_name, variant, None);
-        self.add(item);
+        self.add_opt(render_struct_pat(RenderContext::new(ctx), strukt, local_name));
     }
 }
 
-fn complete_enum_variants(
+/// Calls the callback for each variant of the provided enum with the path to the variant.
+/// Skips variants that are visible with single segment paths.
+fn enum_variants_with_paths(
     acc: &mut Completions,
     ctx: &CompletionContext,
-    enum_data: hir::Enum,
+    enum_: hir::Enum,
     cb: impl Fn(&mut Completions, &CompletionContext, hir::Variant, hir::ModPath),
 ) {
-    let variants = enum_data.variants(ctx.db);
+    let variants = enum_.variants(ctx.db);
 
     let module = if let Some(module) = ctx.scope.module() {
         // Compute path from the completion site if available.
         module
     } else {
         // Otherwise fall back to the enum's definition site.
-        enum_data.module(ctx.db)
+        enum_.module(ctx.db)
     };
 
     if let Some(impl_) = ctx.impl_def.as_ref().and_then(|impl_| ctx.sema.to_def(impl_)) {
-        if impl_.self_ty(ctx.db).as_adt() == Some(hir::Adt::Enum(enum_data)) {
+        if impl_.self_ty(ctx.db).as_adt() == Some(hir::Adt::Enum(enum_)) {
             for &variant in &variants {
                 let self_path = hir::ModPath::from_segments(
                     hir::PathKind::Plain,
diff --git a/crates/ide_completion/src/completions/attribute.rs b/crates/ide_completion/src/completions/attribute.rs
index 6df569c2a..78fc30e16 100644
--- a/crates/ide_completion/src/completions/attribute.rs
+++ b/crates/ide_completion/src/completions/attribute.rs
@@ -17,12 +17,14 @@ use crate::{
 
 mod derive;
 mod lint;
+mod repr;
 
 pub(crate) fn complete_attribute(acc: &mut Completions, ctx: &CompletionContext) -> Option<()> {
     let attribute = ctx.attribute_under_caret.as_ref()?;
     match (attribute.path().and_then(|p| p.as_single_name_ref()), attribute.token_tree()) {
         (Some(path), Some(token_tree)) => match path.text().as_str() {
             "derive" => derive::complete_derive(acc, ctx, token_tree),
+            "repr" => repr::complete_repr(acc, ctx, token_tree),
             "feature" => lint::complete_lint(acc, ctx, token_tree, FEATURES),
             "allow" | "warn" | "deny" | "forbid" => {
                 lint::complete_lint(acc, ctx, token_tree.clone(), DEFAULT_LINTS);
@@ -322,7 +324,7 @@ mod tests {
 
     use expect_test::{expect, Expect};
 
-    use crate::{test_utils::completion_list, CompletionKind};
+    use crate::tests::completion_list;
 
     #[test]
     fn attributes_are_sorted() {
@@ -341,7 +343,7 @@ mod tests {
     }
 
     fn check(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::Attribute);
+        let actual = completion_list(ra_fixture);
         expect.assert_eq(&actual);
     }
 
@@ -792,6 +794,7 @@ mod tests {
 
     #[test]
     fn complete_attribute_on_expr() {
+        cov_mark::check!(no_keyword_completion_in_attr_of_expr);
         check(
             r#"fn main() { #[$0] foo() }"#,
             expect![[r#"
diff --git a/crates/ide_completion/src/completions/attribute/derive.rs b/crates/ide_completion/src/completions/attribute/derive.rs
index d526824fb..6fe41e0d6 100644
--- a/crates/ide_completion/src/completions/attribute/derive.rs
+++ b/crates/ide_completion/src/completions/attribute/derive.rs
@@ -31,6 +31,8 @@ pub(super) fn complete_derive(
                 let lookup = components.join(", ");
                 let label = components.iter().rev().join(", ");
                 (label, Some(lookup))
+            } else if existing_derives.contains(&derive) {
+                continue;
             } else {
                 (derive, None)
             };
@@ -80,10 +82,31 @@ const DEFAULT_DERIVE_COMPLETIONS: &[DeriveDependencies] = &[
 mod tests {
     use expect_test::{expect, Expect};
 
-    use crate::{test_utils::completion_list, CompletionKind};
+    use crate::tests::completion_list;
 
     fn check(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::Attribute);
+        let builtin_derives = r#"
+#[rustc_builtin_macro]
+pub macro Clone {}
+#[rustc_builtin_macro]
+pub macro Copy {}
+#[rustc_builtin_macro]
+pub macro Default {}
+#[rustc_builtin_macro]
+pub macro Debug {}
+#[rustc_builtin_macro]
+pub macro Hash {}
+#[rustc_builtin_macro]
+pub macro PartialEq {}
+#[rustc_builtin_macro]
+pub macro Eq {}
+#[rustc_builtin_macro]
+pub macro PartialOrd {}
+#[rustc_builtin_macro]
+pub macro Ord {}
+
+"#;
+        let actual = completion_list(&format!("{} {}", builtin_derives, ra_fixture));
         expect.assert_eq(&actual);
     }
 
@@ -93,56 +116,53 @@ mod tests {
     }
 
     #[test]
-    #[ignore] // FIXME: Fixtures cant test proc-macros/derives yet as we cant specify them in fixtures
     fn empty_derive() {
         check(
             r#"#[derive($0)] struct Test;"#,
             expect![[r#"
-                at Clone
-                at Clone, Copy
-                at Debug
-                at Default
-                at Hash
-                at PartialEq
-                at PartialEq, Eq
-                at PartialEq, PartialOrd
-                at PartialEq, Eq, PartialOrd, Ord
-            "#]],
+            at PartialEq
+            at Default
+            at PartialEq, Eq
+            at PartialEq, Eq, PartialOrd, Ord
+            at Clone, Copy
+            at Debug
+            at Clone
+            at Hash
+            at PartialEq, PartialOrd
+        "#]],
         );
     }
 
     #[test]
-    #[ignore] // FIXME: Fixtures cant test proc-macros/derives yet as we cant specify them in fixtures
     fn derive_with_input() {
         check(
             r#"#[derive(serde::Serialize, PartialEq, $0)] struct Test;"#,
             expect![[r#"
-                at Clone
+                at Default
+                at Eq
+                at Eq, PartialOrd, Ord
                 at Clone, Copy
                 at Debug
-                at Default
+                at Clone
                 at Hash
-                at Eq
                 at PartialOrd
-                at Eq, PartialOrd, Ord
             "#]],
         )
     }
 
     #[test]
-    #[ignore] // FIXME: Fixtures cant test proc-macros/derives yet as we cant specify them in fixtures
     fn derive_with_input2() {
         check(
             r#"#[derive($0 serde::Serialize, PartialEq)] struct Test;"#,
             expect![[r#"
-                at Clone
+                at Default
+                at Eq
+                at Eq, PartialOrd, Ord
                 at Clone, Copy
                 at Debug
-                at Default
+                at Clone
                 at Hash
-                at Eq
                 at PartialOrd
-                at Eq, PartialOrd, Ord
             "#]],
         )
     }
diff --git a/crates/ide_completion/src/completions/attribute/lint.rs b/crates/ide_completion/src/completions/attribute/lint.rs
index ca99e9759..1ddc38986 100644
--- a/crates/ide_completion/src/completions/attribute/lint.rs
+++ b/crates/ide_completion/src/completions/attribute/lint.rs
@@ -33,8 +33,7 @@ pub(super) fn complete_lint(
 
 #[cfg(test)]
 mod tests {
-
-    use crate::test_utils::check_edit;
+    use crate::tests::check_edit;
 
     #[test]
     fn check_empty() {
diff --git a/crates/ide_completion/src/completions/attribute/repr.rs b/crates/ide_completion/src/completions/attribute/repr.rs
new file mode 100644
index 000000000..92a262a43
--- /dev/null
+++ b/crates/ide_completion/src/completions/attribute/repr.rs
@@ -0,0 +1,199 @@
+//! Completion for representations.
+
+use syntax::ast;
+
+use crate::{
+    context::CompletionContext,
+    item::{CompletionItem, CompletionItemKind, CompletionKind},
+    Completions,
+};
+
+pub(super) fn complete_repr(
+    acc: &mut Completions,
+    ctx: &CompletionContext,
+    derive_input: ast::TokenTree,
+) {
+    if let Some(existing_reprs) = super::parse_comma_sep_input(derive_input) {
+        for repr_completion in REPR_COMPLETIONS {
+            if existing_reprs
+                .iter()
+                .any(|it| repr_completion.label == it || repr_completion.collides.contains(&&**it))
+            {
+                continue;
+            }
+            let mut item = CompletionItem::new(
+                CompletionKind::Attribute,
+                ctx.source_range(),
+                repr_completion.label,
+            );
+            item.kind(CompletionItemKind::Attribute);
+            if let Some(lookup) = repr_completion.lookup {
+                item.lookup_by(lookup);
+            }
+            if let Some((snippet, cap)) = repr_completion.snippet.zip(ctx.config.snippet_cap) {
+                item.insert_snippet(cap, snippet);
+            }
+            item.add_to(acc);
+        }
+    }
+}
+
+struct ReprCompletion {
+    label: &'static str,
+    snippet: Option<&'static str>,
+    lookup: Option<&'static str>,
+    collides: &'static [&'static str],
+}
+
+const fn attr(label: &'static str, collides: &'static [&'static str]) -> ReprCompletion {
+    ReprCompletion { label, snippet: None, lookup: None, collides }
+}
+
+#[rustfmt::skip]
+const REPR_COMPLETIONS: &[ReprCompletion] = &[
+    ReprCompletion { label: "align($0)", snippet: Some("align($0)"), lookup: Some("align"), collides: &["transparent", "packed"] },
+    attr("packed", &["transparent", "align"]),
+    attr("transparent", &["C", "u8", "u16", "u32", "u64", "u128", "usize", "i8", "i16", "i32", "i64", "i128", "isize"]),
+    attr("C", &["transparent"]),
+    attr("u8",     &["transparent", "u16", "u32", "u64", "u128", "usize", "i8", "i16", "i32", "i64", "i128", "isize"]),
+    attr("u16",    &["transparent", "u8", "u32", "u64", "u128", "usize", "i8", "i16", "i32", "i64", "i128", "isize"]),
+    attr("u32",    &["transparent", "u8", "u16", "u64", "u128", "usize", "i8", "i16", "i32", "i64", "i128", "isize"]),
+    attr("u64",    &["transparent", "u8", "u16", "u32", "u128", "usize", "i8", "i16", "i32", "i64", "i128", "isize"]),
+    attr("u128",   &["transparent", "u8", "u16", "u32", "u64", "usize", "i8", "i16", "i32", "i64", "i128", "isize"]),
+    attr("usize",  &["transparent", "u8", "u16", "u32", "u64", "u128", "i8", "i16", "i32", "i64", "i128", "isize"]),
+    attr("i8",     &["transparent", "u8", "u16", "u32", "u64", "u128", "usize", "i16", "i32", "i64", "i128", "isize"]),
+    attr("i16",    &["transparent", "u8", "u16", "u32", "u64", "u128", "usize", "i8", "i32", "i64", "i128", "isize"]),
+    attr("i32",    &["transparent", "u8", "u16", "u32", "u64", "u128", "usize", "i8", "i16", "i64", "i128", "isize"]),
+    attr("i64",    &["transparent", "u8", "u16", "u32", "u64", "u128", "usize", "i8", "i16", "i32", "i128", "isize"]),
+    attr("i28",    &["transparent", "u8", "u16", "u32", "u64", "u128", "usize", "i8", "i16", "i32", "i64", "isize"]),
+    attr("isize",  &["transparent", "u8", "u16", "u32", "u64", "u128", "usize", "i8", "i16", "i32", "i64", "i128"]),
+];
+
+#[cfg(test)]
+mod tests {
+    use expect_test::{expect, Expect};
+
+    use crate::tests::completion_list;
+
+    fn check(ra_fixture: &str, expect: Expect) {
+        let actual = completion_list(ra_fixture);
+        expect.assert_eq(&actual);
+    }
+
+    #[test]
+    fn no_completion_for_incorrect_repr() {
+        check(r#"#[repr{$0)] struct Test;"#, expect![[]])
+    }
+
+    #[test]
+    fn empty() {
+        check(
+            r#"#[repr($0)] struct Test;"#,
+            expect![[r#"
+                at align($0)
+                at packed
+                at transparent
+                at C
+                at u8
+                at u16
+                at u32
+                at u64
+                at u128
+                at usize
+                at i8
+                at i16
+                at i32
+                at i64
+                at i28
+                at isize
+            "#]],
+        );
+    }
+
+    #[test]
+    fn transparent() {
+        check(r#"#[repr(transparent, $0)] struct Test;"#, expect![[r#""#]]);
+    }
+
+    #[test]
+    fn align() {
+        check(
+            r#"#[repr(align(1), $0)] struct Test;"#,
+            expect![[r#"
+                at align($0)
+                at transparent
+                at C
+                at u8
+                at u16
+                at u32
+                at u64
+                at u128
+                at usize
+                at i8
+                at i16
+                at i32
+                at i64
+                at i28
+                at isize
+            "#]],
+        );
+    }
+
+    #[test]
+    fn packed() {
+        check(
+            r#"#[repr(packed, $0)] struct Test;"#,
+            expect![[r#"
+                at transparent
+                at C
+                at u8
+                at u16
+                at u32
+                at u64
+                at u128
+                at usize
+                at i8
+                at i16
+                at i32
+                at i64
+                at i28
+                at isize
+            "#]],
+        );
+    }
+
+    #[test]
+    fn c() {
+        check(
+            r#"#[repr(C, $0)] struct Test;"#,
+            expect![[r#"
+                at align($0)
+                at packed
+                at u8
+                at u16
+                at u32
+                at u64
+                at u128
+                at usize
+                at i8
+                at i16
+                at i32
+                at i64
+                at i28
+                at isize
+            "#]],
+        );
+    }
+
+    #[test]
+    fn prim() {
+        check(
+            r#"#[repr(usize, $0)] struct Test;"#,
+            expect![[r#"
+                at align($0)
+                at packed
+                at C
+            "#]],
+        );
+    }
+}
diff --git a/crates/ide_completion/src/completions/dot.rs b/crates/ide_completion/src/completions/dot.rs
index 9552875c1..286d7cb67 100644
--- a/crates/ide_completion/src/completions/dot.rs
+++ b/crates/ide_completion/src/completions/dot.rs
@@ -101,10 +101,10 @@ fn complete_methods(
 mod tests {
     use expect_test::{expect, Expect};
 
-    use crate::{test_utils::completion_list, CompletionKind};
+    use crate::{tests::filtered_completion_list, CompletionKind};
 
     fn check(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::Reference);
+        let actual = filtered_completion_list(ra_fixture, CompletionKind::Reference);
         expect.assert_eq(&actual);
     }
 
@@ -498,10 +498,7 @@ mod foo {
     fn issue_8931() {
         check(
             r#"
-#[lang = "fn_once"]
-trait FnOnce<Args> {
-    type Output;
-}
+//- minicore: fn
 struct S;
 
 struct Foo;
diff --git a/crates/ide_completion/src/completions/flyimport.rs b/crates/ide_completion/src/completions/flyimport.rs
index 30b8d44bd..814c15653 100644
--- a/crates/ide_completion/src/completions/flyimport.rs
+++ b/crates/ide_completion/src/completions/flyimport.rs
@@ -109,7 +109,7 @@ pub(crate) fn import_on_the_fly(acc: &mut Completions, ctx: &CompletionContext)
     if !ctx.config.enable_imports_on_the_fly {
         return None;
     }
-    if ctx.use_item_syntax.is_some()
+    if ctx.in_use_tree()
         || ctx.is_path_disallowed()
         || ctx.expects_item()
         || ctx.expects_assoc_item()
@@ -227,11 +227,11 @@ mod tests {
 
     use crate::{
         item::CompletionKind,
-        test_utils::{check_edit, check_edit_with_config, completion_list, TEST_CONFIG},
+        tests::{check_edit, check_edit_with_config, filtered_completion_list, TEST_CONFIG},
     };
 
     fn check(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::Magic);
+        let actual = filtered_completion_list(ra_fixture, CompletionKind::Magic);
         expect.assert_eq(&actual);
     }
 
diff --git a/crates/ide_completion/src/completions/fn_param.rs b/crates/ide_completion/src/completions/fn_param.rs
index cb90e8a3e..c9f0e2473 100644
--- a/crates/ide_completion/src/completions/fn_param.rs
+++ b/crates/ide_completion/src/completions/fn_param.rs
@@ -64,10 +64,10 @@ pub(crate) fn complete_fn_param(acc: &mut Completions, ctx: &CompletionContext)
 mod tests {
     use expect_test::{expect, Expect};
 
-    use crate::{test_utils::completion_list, CompletionKind};
+    use crate::{tests::filtered_completion_list, CompletionKind};
 
     fn check(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::Magic);
+        let actual = filtered_completion_list(ra_fixture, CompletionKind::Magic);
         expect.assert_eq(&actual);
     }
 
diff --git a/crates/ide_completion/src/completions/keyword.rs b/crates/ide_completion/src/completions/keyword.rs
index ba13d3707..407f796ef 100644
--- a/crates/ide_completion/src/completions/keyword.rs
+++ b/crates/ide_completion/src/completions/keyword.rs
@@ -18,26 +18,22 @@ pub(crate) fn complete_use_tree_keyword(acc: &mut Completions, ctx: &CompletionC
         item
     };
 
-    if ctx.use_item_syntax.is_some() {
-        let qual = ctx.path_qual();
-        if qual.is_none() {
-            kw_completion("crate::").add_to(acc);
-        }
-        kw_completion("self").add_to(acc);
-        if iter::successors(qual.cloned(), |p| p.qualifier())
-            .all(|p| p.segment().and_then(|s| s.super_token()).is_some())
-        {
-            kw_completion("super::").add_to(acc);
-        }
-    }
-
-    // Suggest .await syntax for types that implement Future trait
-    if let Some(receiver) = ctx.dot_receiver() {
-        if let Some(ty) = ctx.sema.type_of_expr(receiver) {
-            if ty.impls_future(ctx.db) {
-                let mut item = kw_completion("await");
-                item.detail("expr.await");
-                item.add_to(acc);
+    if ctx.in_use_tree() {
+        match &ctx.path_context {
+            Some(PathCompletionContext { qualifier: Some(qual), use_tree_parent, .. }) => {
+                if iter::successors(Some(qual.clone()), |p| p.qualifier())
+                    .all(|p| p.segment().and_then(|s| s.super_token()).is_some())
+                {
+                    kw_completion("super::").add_to(acc);
+                }
+                if *use_tree_parent {
+                    kw_completion("self").add_to(acc);
+                }
+            }
+            _ => {
+                kw_completion("crate::").add_to(acc);
+                kw_completion("self::").add_to(acc);
+                kw_completion("super::").add_to(acc);
             }
         };
     }
@@ -52,6 +48,23 @@ pub(crate) fn complete_expr_keyword(acc: &mut Completions, ctx: &CompletionConte
         cov_mark::hit!(no_keyword_completion_in_record_lit);
         return;
     }
+    if ctx.attribute_under_caret.is_some() {
+        cov_mark::hit!(no_keyword_completion_in_attr_of_expr);
+        return;
+    }
+
+    // Suggest .await syntax for types that implement Future trait
+    if let Some(receiver) = ctx.dot_receiver() {
+        if let Some(ty) = ctx.sema.type_of_expr(receiver) {
+            if ty.impls_future(ctx.db) {
+                let mut item =
+                    CompletionItem::new(CompletionKind::Keyword, ctx.source_range(), "await");
+                item.kind(CompletionItemKind::Keyword).detail("expr.await");
+                item.add_to(acc);
+            }
+        };
+    }
+
     let mut add_keyword = |kw, snippet| add_keyword(ctx, acc, kw, snippet);
 
     let expects_assoc_item = ctx.expects_assoc_item();
@@ -60,6 +73,9 @@ pub(crate) fn complete_expr_keyword(acc: &mut Completions, ctx: &CompletionConte
 
     if ctx.has_impl_or_trait_prev_sibling() {
         add_keyword("where", "where ");
+        if ctx.has_impl_prev_sibling() {
+            add_keyword("for", "for ");
+        }
         return;
     }
     if ctx.previous_token_is(T![unsafe]) {
@@ -75,7 +91,9 @@ pub(crate) fn complete_expr_keyword(acc: &mut Completions, ctx: &CompletionConte
         return;
     }
 
-    if expects_item || ctx.expects_non_trait_assoc_item() || ctx.expect_record_field() {
+    if !ctx.has_visibility_prev_sibling()
+        && (expects_item || ctx.expects_non_trait_assoc_item() || ctx.expect_field())
+    {
         add_keyword("pub(crate)", "pub(crate) ");
         add_keyword("pub", "pub ");
     }
@@ -88,11 +106,13 @@ pub(crate) fn complete_expr_keyword(acc: &mut Completions, ctx: &CompletionConte
     }
 
     if expects_item || has_block_expr_parent {
+        if !ctx.has_visibility_prev_sibling() {
+            add_keyword("impl", "impl $1 {\n    $0\n}");
+            add_keyword("extern", "extern $0");
+        }
         add_keyword("use", "use $0");
-        add_keyword("impl", "impl $1 {\n    $0\n}");
         add_keyword("trait", "trait $1 {\n    $0\n}");
         add_keyword("static", "static $0");
-        add_keyword("extern", "extern $0");
         add_keyword("mod", "mod $0");
     }
 
@@ -102,6 +122,10 @@ pub(crate) fn complete_expr_keyword(acc: &mut Completions, ctx: &CompletionConte
         add_keyword("union", "union $1 {\n    $0\n}");
     }
 
+    if ctx.expects_type() {
+        return;
+    }
+
     if ctx.expects_expression() {
         if !has_block_expr_parent {
             add_keyword("unsafe", "unsafe {\n    $0\n}");
@@ -186,75 +210,16 @@ mod tests {
     use expect_test::{expect, Expect};
 
     use crate::{
-        test_utils::{check_edit, completion_list},
+        tests::{check_edit, filtered_completion_list},
         CompletionKind,
     };
 
     fn check(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::Keyword);
+        let actual = filtered_completion_list(ra_fixture, CompletionKind::Keyword);
         expect.assert_eq(&actual)
     }
 
     #[test]
-    fn test_keywords_in_use_stmt() {
-        check(
-            r"use $0",
-            expect![[r#"
-                kw crate::
-                kw self
-                kw super::
-            "#]],
-        );
-
-        // FIXME: `self` shouldn't be shown here and the check below
-        check(
-            r"use a::$0",
-            expect![[r#"
-            kw self
-        "#]],
-        );
-
-        check(
-            r"use super::$0",
-            expect![[r#"
-                kw self
-                kw super::
-            "#]],
-        );
-
-        check(
-            r"use a::{b, $0}",
-            expect![[r#"
-            kw self
-        "#]],
-        );
-    }
-
-    #[test]
-    fn test_keywords_at_source_file_level() {
-        check(
-            r"m$0",
-            expect![[r#"
-                kw pub(crate)
-                kw pub
-                kw unsafe
-                kw fn
-                kw const
-                kw type
-                kw use
-                kw impl
-                kw trait
-                kw static
-                kw extern
-                kw mod
-                kw enum
-                kw struct
-                kw union
-            "#]],
-        );
-    }
-
-    #[test]
     fn test_keywords_in_function() {
         check(
             r"fn quux() { $0 }",
@@ -263,11 +228,11 @@ mod tests {
                 kw fn
                 kw const
                 kw type
-                kw use
                 kw impl
+                kw extern
+                kw use
                 kw trait
                 kw static
-                kw extern
                 kw mod
                 kw match
                 kw while
@@ -291,11 +256,11 @@ mod tests {
                 kw fn
                 kw const
                 kw type
-                kw use
                 kw impl
+                kw extern
+                kw use
                 kw trait
                 kw static
-                kw extern
                 kw mod
                 kw match
                 kw while
@@ -319,11 +284,11 @@ mod tests {
                 kw fn
                 kw const
                 kw type
-                kw use
                 kw impl
+                kw extern
+                kw use
                 kw trait
                 kw static
-                kw extern
                 kw mod
                 kw match
                 kw while
@@ -370,49 +335,6 @@ fn quux() -> i32 {
     }
 
     #[test]
-    fn test_keywords_in_trait_def() {
-        check(
-            r"trait My { $0 }",
-            expect![[r#"
-                kw unsafe
-                kw fn
-                kw const
-                kw type
-            "#]],
-        );
-    }
-
-    #[test]
-    fn test_keywords_in_impl_def() {
-        check(
-            r"impl My { $0 }",
-            expect![[r#"
-                kw pub(crate)
-                kw pub
-                kw unsafe
-                kw fn
-                kw const
-                kw type
-            "#]],
-        );
-    }
-
-    #[test]
-    fn test_keywords_in_impl_def_with_attr() {
-        check(
-            r"impl My { #[foo] $0 }",
-            expect![[r#"
-                kw pub(crate)
-                kw pub
-                kw unsafe
-                kw fn
-                kw const
-                kw type
-            "#]],
-        );
-    }
-
-    #[test]
     fn test_keywords_in_loop() {
         check(
             r"fn my() { loop { $0 } }",
@@ -421,11 +343,11 @@ fn quux() -> i32 {
                 kw fn
                 kw const
                 kw type
-                kw use
                 kw impl
+                kw extern
+                kw use
                 kw trait
                 kw static
-                kw extern
                 kw mod
                 kw match
                 kw while
@@ -443,18 +365,6 @@ fn quux() -> i32 {
     }
 
     #[test]
-    fn test_keywords_after_unsafe_in_item_list() {
-        check(
-            r"unsafe $0",
-            expect![[r#"
-                kw fn
-                kw trait
-                kw impl
-            "#]],
-        );
-    }
-
-    #[test]
     fn test_keywords_after_unsafe_in_block_expr() {
         check(
             r"fn my_fn() { unsafe $0 }",
@@ -467,44 +377,6 @@ fn quux() -> i32 {
     }
 
     #[test]
-    fn test_mut_in_ref_and_in_fn_parameters_list() {
-        check(
-            r"fn my_fn(&$0) {}",
-            expect![[r#"
-                kw mut
-            "#]],
-        );
-        check(
-            r"fn my_fn($0) {}",
-            expect![[r#"
-                kw mut
-            "#]],
-        );
-        check(
-            r"fn my_fn() { let &$0 }",
-            expect![[r#"
-                kw mut
-            "#]],
-        );
-    }
-
-    #[test]
-    fn test_where_keyword() {
-        check(
-            r"trait A $0",
-            expect![[r#"
-                kw where
-            "#]],
-        );
-        check(
-            r"impl A $0",
-            expect![[r#"
-                kw where
-            "#]],
-        );
-    }
-
-    #[test]
     fn no_keyword_completion_in_comments() {
         cov_mark::check!(no_keyword_completion_in_comments);
         check(
@@ -536,17 +408,11 @@ Some multi-line comment$0
     fn test_completion_await_impls_future() {
         check(
             r#"
-//- /main.rs crate:main deps:std
-use std::future::*;
+//- minicore: future
+use core::future::*;
 struct A {}
 impl Future for A {}
 fn foo(a: A) { a.$0 }
-
-//- /std/lib.rs crate:std
-pub mod future {
-    #[lang = "future_trait"]
-    pub trait Future {}
-}
 "#,
             expect![[r#"
                 kw await expr.await
@@ -555,20 +421,12 @@ pub mod future {
 
         check(
             r#"
-//- /main.rs crate:main deps:std
+//- minicore: future
 use std::future::*;
 fn foo() {
     let a = async {};
     a.$0
 }
-
-//- /std/lib.rs crate:std
-pub mod future {
-    #[lang = "future_trait"]
-    pub trait Future {
-        type Output;
-    }
-}
 "#,
             expect![[r#"
                 kw await expr.await
@@ -595,22 +453,6 @@ pub mod future {
     }
 
     #[test]
-    fn before_field() {
-        check(
-            r#"
-struct Foo {
-    $0
-    pub f: i32,
-}
-"#,
-            expect![[r#"
-                kw pub(crate)
-                kw pub
-            "#]],
-        )
-    }
-
-    #[test]
     fn skip_struct_initializer() {
         cov_mark::check!(no_keyword_completion_in_record_lit);
         check(
diff --git a/crates/ide_completion/src/completions/lifetime.rs b/crates/ide_completion/src/completions/lifetime.rs
index 8ccccb646..abf6935c9 100644
--- a/crates/ide_completion/src/completions/lifetime.rs
+++ b/crates/ide_completion/src/completions/lifetime.rs
@@ -49,18 +49,11 @@ pub(crate) fn complete_label(acc: &mut Completions, ctx: &CompletionContext) {
 mod tests {
     use expect_test::{expect, Expect};
 
-    use crate::{
-        test_utils::{check_edit, completion_list_with_config, TEST_CONFIG},
-        CompletionConfig, CompletionKind,
-    };
+    use crate::tests::{check_edit, completion_list};
 
     fn check(ra_fixture: &str, expect: Expect) {
-        check_with_config(TEST_CONFIG, ra_fixture, expect);
-    }
-
-    fn check_with_config(config: CompletionConfig, ra_fixture: &str, expect: Expect) {
-        let actual = completion_list_with_config(config, ra_fixture, CompletionKind::Reference);
-        expect.assert_eq(&actual)
+        let actual = completion_list(ra_fixture);
+        expect.assert_eq(&actual);
     }
 
     #[test]
diff --git a/crates/ide_completion/src/completions/mod_.rs b/crates/ide_completion/src/completions/mod_.rs
index 6a5746fb9..1c864c0e7 100644
--- a/crates/ide_completion/src/completions/mod_.rs
+++ b/crates/ide_completion/src/completions/mod_.rs
@@ -141,11 +141,11 @@ fn module_chain_to_containing_module_file(
 
 #[cfg(test)]
 mod tests {
-    use crate::{test_utils::completion_list, CompletionKind};
+    use crate::tests::completion_list;
     use expect_test::{expect, Expect};
 
     fn check(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::Magic);
+        let actual = completion_list(ra_fixture);
         expect.assert_eq(&actual);
     }
 
@@ -153,17 +153,17 @@ mod tests {
     fn lib_module_completion() {
         check(
             r#"
-            //- /lib.rs
-            mod $0
-            //- /foo.rs
-            fn foo() {}
-            //- /foo/ignored_foo.rs
-            fn ignored_foo() {}
-            //- /bar/mod.rs
-            fn bar() {}
-            //- /bar/ignored_bar.rs
-            fn ignored_bar() {}
-        "#,
+//- /lib.rs
+mod $0
+//- /foo.rs
+fn foo() {}
+//- /foo/ignored_foo.rs
+fn ignored_foo() {}
+//- /bar/mod.rs
+fn bar() {}
+//- /bar/ignored_bar.rs
+fn ignored_bar() {}
+"#,
             expect![[r#"
                 md foo;
                 md bar;
@@ -175,13 +175,13 @@ mod tests {
     fn no_module_completion_with_module_body() {
         check(
             r#"
-            //- /lib.rs
-            mod $0 {
+//- /lib.rs
+mod $0 {
 
-            }
-            //- /foo.rs
-            fn foo() {}
-        "#,
+}
+//- /foo.rs
+fn foo() {}
+"#,
             expect![[r#""#]],
         );
     }
@@ -190,17 +190,17 @@ mod tests {
     fn main_module_completion() {
         check(
             r#"
-            //- /main.rs
-            mod $0
-            //- /foo.rs
-            fn foo() {}
-            //- /foo/ignored_foo.rs
-            fn ignored_foo() {}
-            //- /bar/mod.rs
-            fn bar() {}
-            //- /bar/ignored_bar.rs
-            fn ignored_bar() {}
-        "#,
+//- /main.rs
+mod $0
+//- /foo.rs
+fn foo() {}
+//- /foo/ignored_foo.rs
+fn ignored_foo() {}
+//- /bar/mod.rs
+fn bar() {}
+//- /bar/ignored_bar.rs
+fn ignored_bar() {}
+"#,
             expect![[r#"
                 md foo;
                 md bar;
@@ -212,13 +212,13 @@ mod tests {
     fn main_test_module_completion() {
         check(
             r#"
-            //- /main.rs
-            mod tests {
-                mod $0;
-            }
-            //- /tests/foo.rs
-            fn foo() {}
-        "#,
+//- /main.rs
+mod tests {
+    mod $0;
+}
+//- /tests/foo.rs
+fn foo() {}
+"#,
             expect![[r#"
                 md foo
             "#]],
@@ -229,19 +229,19 @@ mod tests {
     fn directly_nested_module_completion() {
         check(
             r#"
-            //- /lib.rs
-            mod foo;
-            //- /foo.rs
-            mod $0;
-            //- /foo/bar.rs
-            fn bar() {}
-            //- /foo/bar/ignored_bar.rs
-            fn ignored_bar() {}
-            //- /foo/baz/mod.rs
-            fn baz() {}
-            //- /foo/moar/ignored_moar.rs
-            fn ignored_moar() {}
-        "#,
+//- /lib.rs
+mod foo;
+//- /foo.rs
+mod $0;
+//- /foo/bar.rs
+fn bar() {}
+//- /foo/bar/ignored_bar.rs
+fn ignored_bar() {}
+//- /foo/baz/mod.rs
+fn baz() {}
+//- /foo/moar/ignored_moar.rs
+fn ignored_moar() {}
+"#,
             expect![[r#"
                 md bar
                 md baz
@@ -253,15 +253,15 @@ mod tests {
     fn nested_in_source_module_completion() {
         check(
             r#"
-            //- /lib.rs
-            mod foo;
-            //- /foo.rs
-            mod bar {
-                mod $0
-            }
-            //- /foo/bar/baz.rs
-            fn baz() {}
-        "#,
+//- /lib.rs
+mod foo;
+//- /foo.rs
+mod bar {
+    mod $0
+}
+//- /foo/bar/baz.rs
+fn baz() {}
+"#,
             expect![[r#"
                 md baz;
             "#]],
@@ -299,16 +299,16 @@ mod tests {
     fn already_declared_bin_module_completion_omitted() {
         check(
             r#"
-            //- /src/bin.rs crate:main
-            fn main() {}
-            //- /src/bin/foo.rs
-            mod $0
-            //- /src/bin/bar.rs
-            mod foo;
-            fn bar() {}
-            //- /src/bin/bar/bar_ignored.rs
-            fn bar_ignored() {}
-        "#,
+//- /src/bin.rs crate:main
+fn main() {}
+//- /src/bin/foo.rs
+mod $0
+//- /src/bin/bar.rs
+mod foo;
+fn bar() {}
+//- /src/bin/bar/bar_ignored.rs
+fn bar_ignored() {}
+"#,
             expect![[r#""#]],
         );
     }
diff --git a/crates/ide_completion/src/completions/pattern.rs b/crates/ide_completion/src/completions/pattern.rs
index 1daa8595a..bd13a62d7 100644
--- a/crates/ide_completion/src/completions/pattern.rs
+++ b/crates/ide_completion/src/completions/pattern.rs
@@ -13,7 +13,7 @@ pub(crate) fn complete_pattern(acc: &mut Completions, ctx: &CompletionContext) {
         if let Some(hir::Adt::Enum(e)) =
             ctx.expected_type.as_ref().and_then(|ty| ty.strip_references().as_adt())
         {
-            super::complete_enum_variants(acc, ctx, e, |acc, ctx, variant, path| {
+            super::enum_variants_with_paths(acc, ctx, e, |acc, ctx, variant, path| {
                 acc.add_qualified_variant_pat(ctx, variant, path.clone());
                 acc.add_qualified_enum_variant(ctx, variant, path);
             });
@@ -55,398 +55,3 @@ pub(crate) fn complete_pattern(acc: &mut Completions, ctx: &CompletionContext) {
         }
     });
 }
-
-#[cfg(test)]
-mod tests {
-    use expect_test::{expect, Expect};
-
-    use crate::{
-        test_utils::{check_edit, completion_list},
-        CompletionKind,
-    };
-
-    fn check(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::Reference);
-        expect.assert_eq(&actual)
-    }
-
-    fn check_snippet(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::Snippet);
-        expect.assert_eq(&actual)
-    }
-
-    #[test]
-    fn completes_enum_variants_and_modules() {
-        check(
-            r#"
-enum E { X }
-use self::E::X;
-const Z: E = E::X;
-mod m {}
-
-static FOO: E = E::X;
-struct Bar { f: u32 }
-
-fn foo() {
-   match E::X { a$0 }
-}
-"#,
-            expect![[r#"
-                en E
-                ct Z
-                st Bar
-                ev X
-                md m
-            "#]],
-        );
-    }
-
-    #[test]
-    fn does_not_complete_non_fn_macros() {
-        check(
-            r#"
-macro_rules! m { ($e:expr) => { $e } }
-enum E { X }
-
-#[rustc_builtin_macro]
-macro Clone {}
-
-fn foo() {
-   match E::X { $0 }
-}
-"#,
-            expect![[r#"
-                ev E::X  ()
-                en E
-                ma m!(…) macro_rules! m
-            "#]],
-        );
-    }
-
-    #[test]
-    fn completes_in_simple_macro_call() {
-        check(
-            r#"
-macro_rules! m { ($e:expr) => { $e } }
-enum E { X }
-
-fn foo() {
-   m!(match E::X { a$0 })
-}
-"#,
-            expect![[r#"
-                ev E::X  ()
-                en E
-                ma m!(…) macro_rules! m
-            "#]],
-        );
-    }
-
-    #[test]
-    fn completes_in_irrefutable_let() {
-        check(
-            r#"
-enum E { X }
-use self::E::X;
-const Z: E = E::X;
-mod m {}
-
-static FOO: E = E::X;
-struct Bar { f: u32 }
-
-fn foo() {
-   let a$0
-}
-"#,
-            expect![[r#"
-                st Bar
-            "#]],
-        );
-    }
-
-    #[test]
-    fn completes_in_param() {
-        check(
-            r#"
-enum E { X }
-
-static FOO: E = E::X;
-struct Bar { f: u32 }
-
-fn foo(a$0) {
-}
-"#,
-            expect![[r#"
-                st Bar
-            "#]],
-        );
-    }
-
-    #[test]
-    fn completes_pat_in_let() {
-        check_snippet(
-            r#"
-struct Bar { f: u32 }
-
-fn foo() {
-   let a$0
-}
-"#,
-            expect![[r#"
-                bn Bar Bar { f$1 }$0
-            "#]],
-        );
-    }
-
-    #[test]
-    fn completes_param_pattern() {
-        check_snippet(
-            r#"
-struct Foo { bar: String, baz: String }
-struct Bar(String, String);
-struct Baz;
-fn outer(a$0) {}
-"#,
-            expect![[r#"
-                bn Foo Foo { bar$1, baz$2 }: Foo$0
-                bn Bar Bar($1, $2): Bar$0
-            "#]],
-        )
-    }
-
-    #[test]
-    fn completes_let_pattern() {
-        check_snippet(
-            r#"
-struct Foo { bar: String, baz: String }
-struct Bar(String, String);
-struct Baz;
-fn outer() {
-    let a$0
-}
-"#,
-            expect![[r#"
-                bn Foo Foo { bar$1, baz$2 }$0
-                bn Bar Bar($1, $2)$0
-            "#]],
-        )
-    }
-
-    #[test]
-    fn completes_refutable_pattern() {
-        check_snippet(
-            r#"
-struct Foo { bar: i32, baz: i32 }
-struct Bar(String, String);
-struct Baz;
-fn outer() {
-    match () {
-        a$0
-    }
-}
-"#,
-            expect![[r#"
-                bn Foo Foo { bar$1, baz$2 }$0
-                bn Bar Bar($1, $2)$0
-            "#]],
-        )
-    }
-
-    #[test]
-    fn omits_private_fields_pat() {
-        check_snippet(
-            r#"
-mod foo {
-    pub struct Foo { pub bar: i32, baz: i32 }
-    pub struct Bar(pub String, String);
-    pub struct Invisible(String, String);
-}
-use foo::*;
-
-fn outer() {
-    match () {
-        a$0
-    }
-}
-"#,
-            expect![[r#"
-                bn Foo Foo { bar$1, .. }$0
-                bn Bar Bar($1, ..)$0
-            "#]],
-        )
-    }
-
-    #[test]
-    fn only_shows_ident_completion() {
-        check_edit(
-            "Foo",
-            r#"
-struct Foo(i32);
-fn main() {
-    match Foo(92) {
-        a$0(92) => (),
-    }
-}
-"#,
-            r#"
-struct Foo(i32);
-fn main() {
-    match Foo(92) {
-        Foo(92) => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn completes_self_pats() {
-        check_snippet(
-            r#"
-struct Foo(i32);
-impl Foo {
-    fn foo() {
-        match () {
-            a$0
-        }
-    }
-}
-    "#,
-            expect![[r#"
-                bn Self Self($1)$0
-                bn Foo  Foo($1)$0
-            "#]],
-        )
-    }
-
-    #[test]
-    fn completes_qualified_variant() {
-        check_snippet(
-            r#"
-enum Foo {
-    Bar { baz: i32 }
-}
-impl Foo {
-    fn foo() {
-        match {Foo::Bar { baz: 0 }} {
-            B$0
-        }
-    }
-}
-    "#,
-            expect![[r#"
-                bn Self::Bar Self::Bar { baz$1 }$0
-                bn Foo::Bar  Foo::Bar { baz$1 }$0
-            "#]],
-        )
-    }
-
-    #[test]
-    fn completes_enum_variant_matcharm() {
-        check(
-            r#"
-enum Foo { Bar, Baz, Quux }
-
-fn main() {
-    let foo = Foo::Quux;
-    match foo { Qu$0 }
-}
-"#,
-            expect![[r#"
-                ev Foo::Bar  ()
-                ev Foo::Baz  ()
-                ev Foo::Quux ()
-                en Foo
-            "#]],
-        )
-    }
-
-    #[test]
-    fn completes_enum_variant_matcharm_ref() {
-        check(
-            r#"
-enum Foo { Bar, Baz, Quux }
-
-fn main() {
-    let foo = Foo::Quux;
-    match &foo { Qu$0 }
-}
-"#,
-            expect![[r#"
-                ev Foo::Bar  ()
-                ev Foo::Baz  ()
-                ev Foo::Quux ()
-                en Foo
-            "#]],
-        )
-    }
-
-    #[test]
-    fn completes_enum_variant_iflet() {
-        check(
-            r#"
-enum Foo { Bar, Baz, Quux }
-
-fn main() {
-    let foo = Foo::Quux;
-    if let Qu$0 = foo { }
-}
-"#,
-            expect![[r#"
-                ev Foo::Bar  ()
-                ev Foo::Baz  ()
-                ev Foo::Quux ()
-                en Foo
-            "#]],
-        )
-    }
-
-    #[test]
-    fn completes_enum_variant_impl() {
-        check(
-            r#"
-enum Foo { Bar, Baz, Quux }
-impl Foo {
-    fn foo() { match Foo::Bar { Q$0 } }
-}
-"#,
-            expect![[r#"
-                ev Self::Bar  ()
-                ev Self::Baz  ()
-                ev Self::Quux ()
-                ev Foo::Bar   ()
-                ev Foo::Baz   ()
-                ev Foo::Quux  ()
-                sp Self
-                en Foo
-            "#]],
-        )
-    }
-
-    #[test]
-    fn completes_in_record_field_pat() {
-        check_snippet(
-            r#"
-struct Foo { bar: Bar }
-struct Bar(u32);
-fn outer(Foo { bar: $0 }: Foo) {}
-"#,
-            expect![[r#"
-                bn Foo Foo { bar$1 }$0
-                bn Bar Bar($1)$0
-            "#]],
-        )
-    }
-
-    #[test]
-    fn skips_in_record_field_pat_name() {
-        check_snippet(
-            r#"
-struct Foo { bar: Bar }
-struct Bar(u32);
-fn outer(Foo { bar$0 }: Foo) {}
-"#,
-            expect![[r#""#]],
-        )
-    }
-}
diff --git a/crates/ide_completion/src/completions/postfix.rs b/crates/ide_completion/src/completions/postfix.rs
index 9f98b21be..4e20ec003 100644
--- a/crates/ide_completion/src/completions/postfix.rs
+++ b/crates/ide_completion/src/completions/postfix.rs
@@ -307,12 +307,12 @@ mod tests {
     use expect_test::{expect, Expect};
 
     use crate::{
-        test_utils::{check_edit, completion_list},
+        tests::{check_edit, filtered_completion_list},
         CompletionKind,
     };
 
     fn check(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::Postfix);
+        let actual = filtered_completion_list(ra_fixture, CompletionKind::Postfix);
         expect.assert_eq(&actual)
     }
 
@@ -436,18 +436,15 @@ fn main() {
         check_edit(
             "ifl",
             r#"
-enum Option<T> { Some(T), None }
-
+//- minicore: option
 fn main() {
-    let bar = Option::Some(true);
+    let bar = Some(true);
     bar.$0
 }
 "#,
             r#"
-enum Option<T> { Some(T), None }
-
 fn main() {
-    let bar = Option::Some(true);
+    let bar = Some(true);
     if let Some($1) = bar {
     $0
 }
@@ -461,18 +458,15 @@ fn main() {
         check_edit(
             "match",
             r#"
-enum Result<T, E> { Ok(T), Err(E) }
-
+//- minicore: result
 fn main() {
-    let bar = Result::Ok(true);
+    let bar = Ok(true);
     bar.$0
 }
 "#,
             r#"
-enum Result<T, E> { Ok(T), Err(E) }
-
 fn main() {
-    let bar = Result::Ok(true);
+    let bar = Ok(true);
     match bar {
     Ok(${1:_}) => {$2},
     Err(${3:_}) => {$0},
@@ -515,18 +509,15 @@ fn main() {
         check_edit(
             "ifl",
             r#"
-enum Option<T> { Some(T), None }
-
+//- minicore: option
 fn main() {
-    let bar = &Option::Some(true);
+    let bar = &Some(true);
     bar.$0
 }
 "#,
             r#"
-enum Option<T> { Some(T), None }
-
 fn main() {
-    let bar = &Option::Some(true);
+    let bar = &Some(true);
     if let Some($1) = bar {
     $0
 }
diff --git a/crates/ide_completion/src/completions/qualified_path.rs b/crates/ide_completion/src/completions/qualified_path.rs
index 6083537b7..1b8997ecf 100644
--- a/crates/ide_completion/src/completions/qualified_path.rs
+++ b/crates/ide_completion/src/completions/qualified_path.rs
@@ -19,6 +19,7 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
         Some(res) => res,
         None => return,
     };
+
     let context_module = ctx.scope.module();
 
     if ctx.expects_item() || ctx.expects_assoc_item() {
@@ -48,7 +49,7 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
         hir::PathResolution::Def(hir::ModuleDef::Module(module)) => {
             let module_scope = module.scope(ctx.db, context_module);
             for (name, def) in module_scope {
-                if ctx.use_item_syntax.is_some() {
+                if ctx.in_use_tree() {
                     if let hir::ScopeDef::Unknown = def {
                         if let Some(name_ref) = ctx.name_ref_syntax.as_ref() {
                             if name_ref.syntax().text() == name.to_string().as_str() {
@@ -60,21 +61,37 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                     }
                 }
 
-                if let hir::ScopeDef::MacroDef(macro_def) = def {
-                    if !macro_def.is_fn_like() {
-                        // Don't suggest attribute macros and derives.
-                        continue;
+                let add_resolution = match def {
+                    // Don't suggest attribute macros and derives.
+                    hir::ScopeDef::MacroDef(mac) => mac.is_fn_like(),
+                    // no values in type places
+                    hir::ScopeDef::ModuleDef(
+                        hir::ModuleDef::Function(_)
+                        | hir::ModuleDef::Variant(_)
+                        | hir::ModuleDef::Static(_),
+                    )
+                    | hir::ScopeDef::Local(_) => !ctx.expects_type(),
+                    // unless its a constant in a generic arg list position
+                    hir::ScopeDef::ModuleDef(hir::ModuleDef::Const(_)) => {
+                        !ctx.expects_type() || ctx.expects_generic_arg()
                     }
-                }
+                    _ => true,
+                };
 
-                acc.add_resolution(ctx, name, &def);
+                if add_resolution {
+                    acc.add_resolution(ctx, name, &def);
+                }
             }
         }
-        hir::PathResolution::Def(def @ hir::ModuleDef::Adt(_))
-        | hir::PathResolution::Def(def @ hir::ModuleDef::TypeAlias(_))
-        | hir::PathResolution::Def(def @ hir::ModuleDef::BuiltinType(_)) => {
+        hir::PathResolution::Def(
+            def
+            @
+            (hir::ModuleDef::Adt(_)
+            | hir::ModuleDef::TypeAlias(_)
+            | hir::ModuleDef::BuiltinType(_)),
+        ) => {
             if let hir::ModuleDef::Adt(hir::Adt::Enum(e)) = def {
-                add_enum_variants(ctx, acc, e);
+                add_enum_variants(acc, ctx, e);
             }
             let ty = match def {
                 hir::ModuleDef::Adt(adt) => adt.ty(ctx.db),
@@ -82,7 +99,7 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                     let ty = a.ty(ctx.db);
                     if let Some(hir::Adt::Enum(e)) = ty.as_adt() {
                         cov_mark::hit!(completes_variant_through_alias);
-                        add_enum_variants(ctx, acc, e);
+                        add_enum_variants(acc, ctx, e);
                     }
                     ty
                 }
@@ -107,11 +124,7 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                     if context_module.map_or(false, |m| !item.is_visible_from(ctx.db, m)) {
                         return None;
                     }
-                    match item {
-                        hir::AssocItem::Function(func) => acc.add_function(ctx, func, None),
-                        hir::AssocItem::Const(ct) => acc.add_const(ctx, ct),
-                        hir::AssocItem::TypeAlias(ty) => acc.add_type_alias(ctx, ty),
-                    }
+                    add_assoc_item(acc, ctx, item);
                     None::<()>
                 });
 
@@ -133,11 +146,7 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                 if context_module.map_or(false, |m| !item.is_visible_from(ctx.db, m)) {
                     continue;
                 }
-                match item {
-                    hir::AssocItem::Function(func) => acc.add_function(ctx, func, None),
-                    hir::AssocItem::Const(ct) => acc.add_const(ctx, ct),
-                    hir::AssocItem::TypeAlias(ty) => acc.add_type_alias(ctx, ty),
-                }
+                add_assoc_item(acc, ctx, item);
             }
         }
         hir::PathResolution::TypeParam(_) | hir::PathResolution::SelfType(_) => {
@@ -149,7 +158,7 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                 };
 
                 if let Some(hir::Adt::Enum(e)) = ty.as_adt() {
-                    add_enum_variants(ctx, acc, e);
+                    add_enum_variants(acc, ctx, e);
                 }
 
                 let traits_in_scope = ctx.scope.traits_in_scope();
@@ -162,11 +171,7 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                     // We might iterate candidates of a trait multiple times here, so deduplicate
                     // them.
                     if seen.insert(item) {
-                        match item {
-                            hir::AssocItem::Function(func) => acc.add_function(ctx, func, None),
-                            hir::AssocItem::Const(ct) => acc.add_const(ctx, ct),
-                            hir::AssocItem::TypeAlias(ty) => acc.add_type_alias(ctx, ty),
-                        }
+                        add_assoc_item(acc, ctx, item);
                     }
                     None::<()>
                 });
@@ -176,82 +181,44 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
     }
 }
 
-fn add_enum_variants(ctx: &CompletionContext, acc: &mut Completions, e: hir::Enum) {
-    for variant in e.variants(ctx.db) {
-        acc.add_enum_variant(ctx, variant, None);
+fn add_assoc_item(acc: &mut Completions, ctx: &CompletionContext, item: hir::AssocItem) {
+    match item {
+        hir::AssocItem::Function(func) if !ctx.expects_type() => acc.add_function(ctx, func, None),
+        hir::AssocItem::Const(ct) if !ctx.expects_type() || ctx.expects_generic_arg() => {
+            acc.add_const(ctx, ct)
+        }
+        hir::AssocItem::TypeAlias(ty) => acc.add_type_alias(ctx, ty),
+        _ => (),
     }
 }
 
+fn add_enum_variants(acc: &mut Completions, ctx: &CompletionContext, e: hir::Enum) {
+    if ctx.expects_type() {
+        return;
+    }
+    e.variants(ctx.db).into_iter().for_each(|variant| acc.add_enum_variant(ctx, variant, None));
+}
+
 #[cfg(test)]
 mod tests {
     use expect_test::{expect, Expect};
 
     use crate::{
-        test_utils::{check_edit, completion_list},
+        tests::{check_edit, filtered_completion_list},
         CompletionKind,
     };
 
     fn check(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::Reference);
+        let actual = filtered_completion_list(ra_fixture, CompletionKind::Reference);
         expect.assert_eq(&actual);
     }
 
     fn check_builtin(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::BuiltinType);
+        let actual = filtered_completion_list(ra_fixture, CompletionKind::BuiltinType);
         expect.assert_eq(&actual);
     }
 
     #[test]
-    fn dont_complete_current_use() {
-        cov_mark::check!(dont_complete_current_use);
-        check(r#"use self::foo$0;"#, expect![[""]]);
-    }
-
-    #[test]
-    fn dont_complete_values_in_type_pos() {
-        check(
-            r#"
-const FOO: () = ();
-static BAR: () = ();
-struct Baz;
-fn foo() {
-    let _: self::$0;
-}
-"#,
-            expect![[r#"
-                st Baz
-            "#]],
-        );
-    }
-
-    #[test]
-    fn dont_complete_enum_variants_in_type_pos() {
-        check(
-            r#"
-enum Foo { Bar }
-fn foo() {
-    let _: Foo::$0;
-}
-"#,
-            expect![[r#""#]],
-        );
-    }
-
-    #[test]
-    fn dont_complete_current_use_in_braces_with_glob() {
-        check(
-            r#"
-mod foo { pub struct S; }
-use self::{foo::*, bar$0};
-"#,
-            expect![[r#"
-                st S
-                md foo
-            "#]],
-        );
-    }
-
-    #[test]
     fn dont_complete_primitive_in_use() {
         check_builtin(r#"use self::$0;"#, expect![[""]]);
     }
@@ -262,134 +229,6 @@ use self::{foo::*, bar$0};
     }
 
     #[test]
-    fn completes_primitives() {
-        check_builtin(
-            r#"fn main() { let _: $0 = 92; }"#,
-            expect![[r#"
-                bt u32
-                bt bool
-                bt u8
-                bt isize
-                bt u16
-                bt u64
-                bt u128
-                bt f32
-                bt i128
-                bt i16
-                bt str
-                bt i64
-                bt char
-                bt f64
-                bt i32
-                bt i8
-                bt usize
-            "#]],
-        );
-    }
-
-    #[test]
-    fn completes_mod_with_same_name_as_function() {
-        check(
-            r#"
-use self::my::$0;
-
-mod my { pub struct Bar; }
-fn my() {}
-"#,
-            expect![[r#"
-                st Bar
-            "#]],
-        );
-    }
-
-    #[test]
-    fn filters_visibility() {
-        check(
-            r#"
-use self::my::$0;
-
-mod my {
-    struct Bar;
-    pub struct Foo;
-    pub use Bar as PublicBar;
-}
-"#,
-            expect![[r#"
-                st Foo
-                st PublicBar
-            "#]],
-        );
-    }
-
-    #[test]
-    fn completes_use_item_starting_with_self() {
-        check(
-            r#"
-use self::m::$0;
-
-mod m { pub struct Bar; }
-"#,
-            expect![[r#"
-                st Bar
-            "#]],
-        );
-    }
-
-    #[test]
-    fn completes_use_item_starting_with_crate() {
-        check(
-            r#"
-//- /lib.rs
-mod foo;
-struct Spam;
-//- /foo.rs
-use crate::Sp$0
-"#,
-            expect![[r#"
-                md foo
-                st Spam
-            "#]],
-        );
-    }
-
-    #[test]
-    fn completes_nested_use_tree() {
-        check(
-            r#"
-//- /lib.rs
-mod foo;
-struct Spam;
-//- /foo.rs
-use crate::{Sp$0};
-"#,
-            expect![[r#"
-                md foo
-                st Spam
-            "#]],
-        );
-    }
-
-    #[test]
-    fn completes_deeply_nested_use_tree() {
-        check(
-            r#"
-//- /lib.rs
-mod foo;
-pub mod bar {
-    pub mod baz {
-        pub struct Spam;
-    }
-}
-//- /foo.rs
-use crate::{bar::{baz::Sp$0}};
-"#,
-            expect![[r#"
-                st Spam
-            "#]],
-        );
-    }
-
-    #[test]
     fn completes_enum_variant() {
         check(
             r#"
@@ -486,22 +325,6 @@ fn foo() { let _ = U::$0 }
     }
 
     #[test]
-    fn completes_use_paths_across_crates() {
-        check(
-            r#"
-//- /main.rs crate:main deps:foo
-use foo::$0;
-
-//- /foo/lib.rs crate:foo
-pub mod bar { pub struct S; }
-"#,
-            expect![[r#"
-                md bar
-            "#]],
-        );
-    }
-
-    #[test]
     fn completes_trait_associated_method_1() {
         check(
             r#"
@@ -683,63 +506,6 @@ fn f() {m::$0}
     }
 
     #[test]
-    fn completes_in_assoc_item_list() {
-        check(
-            r#"
-#[macro_export]
-macro_rules! foo { () => {} }
-mod bar {}
-
-struct MyStruct {}
-impl MyStruct {
-    crate::$0
-}
-"#,
-            expect![[r##"
-                md bar
-                ma foo!(…) #[macro_export] macro_rules! foo
-            "##]],
-        );
-    }
-
-    #[test]
-    fn completes_in_item_list() {
-        check(
-            r#"
-struct MyStruct {}
-#[macro_export]
-macro_rules! foo {}
-mod bar {}
-
-crate::$0
-"#,
-            expect![[r#"
-                md bar
-                ma foo!(…) #[macro_export] macro_rules! foo
-            "#]],
-        )
-    }
-
-    #[test]
-    fn test_super_super_completion() {
-        check(
-            r#"
-mod a {
-    const A: usize = 0;
-    mod b {
-        const B: usize = 0;
-        mod c { use super::super::$0 }
-    }
-}
-"#,
-            expect![[r#"
-                md b
-                ct A
-            "#]],
-        );
-    }
-
-    #[test]
     fn completes_reexported_items_under_correct_name() {
         check(
             r#"
diff --git a/crates/ide_completion/src/completions/record.rs b/crates/ide_completion/src/completions/record.rs
index 0ac47cdbe..e876337f1 100644
--- a/crates/ide_completion/src/completions/record.rs
+++ b/crates/ide_completion/src/completions/record.rs
@@ -48,44 +48,29 @@ pub(crate) fn complete_record(acc: &mut Completions, ctx: &CompletionContext) ->
 #[cfg(test)]
 mod tests {
     use expect_test::{expect, Expect};
-    use ide_db::helpers::FamousDefs;
 
     use crate::{
-        test_utils::{self, completion_list},
+        tests::{check_edit, filtered_completion_list},
         CompletionKind,
     };
 
     fn check(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::Reference);
+        let actual = filtered_completion_list(ra_fixture, CompletionKind::Reference);
         expect.assert_eq(&actual);
     }
 
     fn check_snippet(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(
-            &format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE),
-            CompletionKind::Snippet,
-        );
+        let actual = filtered_completion_list(ra_fixture, CompletionKind::Snippet);
         expect.assert_eq(&actual);
     }
 
-    fn check_edit(what: &str, ra_fixture_before: &str, ra_fixture_after: &str) {
-        test_utils::check_edit(
-            what,
-            &format!(
-                "//- /main.rs crate:main deps:core{}\n{}",
-                ra_fixture_before,
-                FamousDefs::FIXTURE,
-            ),
-            &(ra_fixture_after.to_owned() + "\n"),
-        );
-    }
-
     #[test]
     fn test_record_literal_field_default() {
         let test_code = r#"
+//- minicore: default
 struct S { foo: u32, bar: usize }
 
-impl core::default::Default for S {
+impl Default for S {
     fn default() -> Self {
         S {
             foo: 0,
@@ -121,9 +106,10 @@ fn process(f: S) {
         check_edit(
             "..Default::default()",
             r#"
+//- minicore: default
 struct S { foo: u32, bar: usize }
 
-impl core::default::Default for S {
+impl Default for S {
     fn default() -> Self {
         S {
             foo: 0,
@@ -142,7 +128,7 @@ fn process(f: S) {
             r#"
 struct S { foo: u32, bar: usize }
 
-impl core::default::Default for S {
+impl Default for S {
     fn default() -> Self {
         S {
             foo: 0,
diff --git a/crates/ide_completion/src/completions/snippet.rs b/crates/ide_completion/src/completions/snippet.rs
index b9862de67..cbc20cc2c 100644
--- a/crates/ide_completion/src/completions/snippet.rs
+++ b/crates/ide_completion/src/completions/snippet.rs
@@ -1,6 +1,7 @@
 //! This file provides snippet completions, like `pd` => `eprintln!(...)`.
 
 use ide_db::helpers::SnippetCap;
+use syntax::T;
 
 use crate::{
     context::PathCompletionContext, item::Builder, CompletionContext, CompletionItem,
@@ -35,9 +36,17 @@ pub(crate) fn complete_expr_snippet(acc: &mut Completions, ctx: &CompletionConte
 }
 
 pub(crate) fn complete_item_snippet(acc: &mut Completions, ctx: &CompletionContext) {
-    if !ctx.expects_item() {
+    if !ctx.expects_item()
+        || ctx.previous_token_is(T![unsafe])
+        || ctx.path_qual().is_some()
+        || ctx.has_impl_or_trait_prev_sibling()
+    {
         return;
     }
+    if ctx.has_visibility_prev_sibling() {
+        return; // technically we could do some of these snippet completions if we were to put the
+                // attributes before the vis node.
+    }
     let cap = match ctx.config.snippet_cap {
         Some(it) => it,
         None => return,
@@ -82,10 +91,10 @@ fn ${1:feature}() {
 mod tests {
     use expect_test::{expect, Expect};
 
-    use crate::{test_utils::completion_list, CompletionKind};
+    use crate::{tests::filtered_completion_list, CompletionKind};
 
     fn check(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::Snippet);
+        let actual = filtered_completion_list(ra_fixture, CompletionKind::Snippet);
         expect.assert_eq(&actual)
     }
 
@@ -105,21 +114,4 @@ mod tests {
         check(r#"fn foo(x: i32) { ::foo$0 }"#, expect![[""]]);
         check(r#"fn foo(x: i32) { ::$0 }"#, expect![[""]]);
     }
-
-    #[test]
-    fn completes_snippets_in_items() {
-        check(
-            r#"
-#[cfg(test)]
-mod tests {
-    $0
-}
-"#,
-            expect![[r#"
-                sn tmod (Test module)
-                sn tfn (Test function)
-                sn macro_rules
-            "#]],
-        )
-    }
 }
diff --git a/crates/ide_completion/src/completions/trait_impl.rs b/crates/ide_completion/src/completions/trait_impl.rs
index a60e5f43c..65f0f3843 100644
--- a/crates/ide_completion/src/completions/trait_impl.rs
+++ b/crates/ide_completion/src/completions/trait_impl.rs
@@ -32,7 +32,7 @@
 //! ```
 
 use hir::{self, HasAttrs, HasSource};
-use ide_db::{traits::get_missing_assoc_items, SymbolKind};
+use ide_db::{path_transform::PathTransform, traits::get_missing_assoc_items, SymbolKind};
 use syntax::{
     ast::{self, edit},
     display::function_declaration,
@@ -52,24 +52,26 @@ enum ImplCompletionKind {
 
 pub(crate) fn complete_trait_impl(acc: &mut Completions, ctx: &CompletionContext) {
     if let Some((kind, trigger, impl_def)) = completion_match(ctx.token.clone()) {
-        get_missing_assoc_items(&ctx.sema, &impl_def).into_iter().for_each(|item| match item {
-            hir::AssocItem::Function(fn_item)
-                if kind == ImplCompletionKind::All || kind == ImplCompletionKind::Fn =>
-            {
-                add_function_impl(&trigger, acc, ctx, fn_item)
-            }
-            hir::AssocItem::TypeAlias(type_item)
-                if kind == ImplCompletionKind::All || kind == ImplCompletionKind::TypeAlias =>
-            {
-                add_type_alias_impl(&trigger, acc, ctx, type_item)
-            }
-            hir::AssocItem::Const(const_item)
-                if kind == ImplCompletionKind::All || kind == ImplCompletionKind::Const =>
-            {
-                add_const_impl(&trigger, acc, ctx, const_item)
-            }
-            _ => {}
-        });
+        if let Some(hir_impl) = ctx.sema.to_def(&impl_def) {
+            get_missing_assoc_items(&ctx.sema, &impl_def).into_iter().for_each(|item| match item {
+                hir::AssocItem::Function(fn_item)
+                    if kind == ImplCompletionKind::All || kind == ImplCompletionKind::Fn =>
+                {
+                    add_function_impl(&trigger, acc, ctx, fn_item, hir_impl)
+                }
+                hir::AssocItem::TypeAlias(type_item)
+                    if kind == ImplCompletionKind::All || kind == ImplCompletionKind::TypeAlias =>
+                {
+                    add_type_alias_impl(&trigger, acc, ctx, type_item)
+                }
+                hir::AssocItem::Const(const_item)
+                    if kind == ImplCompletionKind::All || kind == ImplCompletionKind::Const =>
+                {
+                    add_const_impl(&trigger, acc, ctx, const_item, hir_impl)
+                }
+                _ => {}
+            });
+        }
     }
 }
 
@@ -129,6 +131,7 @@ fn add_function_impl(
     acc: &mut Completions,
     ctx: &CompletionContext,
     func: hir::Function,
+    impl_def: hir::Impl,
 ) {
     let fn_name = func.name(ctx.db).to_string();
 
@@ -147,23 +150,55 @@ fn add_function_impl(
         CompletionItemKind::SymbolKind(SymbolKind::Function)
     };
     let range = replacement_range(ctx, fn_def_node);
-    if let Some(src) = func.source(ctx.db) {
-        let function_decl = function_declaration(&src.value);
-        match ctx.config.snippet_cap {
-            Some(cap) => {
-                let snippet = format!("{} {{\n    $0\n}}", function_decl);
-                item.snippet_edit(cap, TextEdit::replace(range, snippet));
-            }
-            None => {
-                let header = format!("{} {{", function_decl);
-                item.text_edit(TextEdit::replace(range, header));
-            }
-        };
-        item.kind(completion_kind);
-        item.add_to(acc);
+
+    if let Some(source) = func.source(ctx.db) {
+        let assoc_item = ast::AssocItem::Fn(source.value);
+        if let Some(transformed_item) = get_transformed_assoc_item(ctx, assoc_item, impl_def) {
+            let transformed_fn = match transformed_item {
+                ast::AssocItem::Fn(func) => func,
+                _ => unreachable!(),
+            };
+
+            let function_decl = function_declaration(&transformed_fn);
+            match ctx.config.snippet_cap {
+                Some(cap) => {
+                    let snippet = format!("{} {{\n    $0\n}}", function_decl);
+                    item.snippet_edit(cap, TextEdit::replace(range, snippet));
+                }
+                None => {
+                    let header = format!("{} {{", function_decl);
+                    item.text_edit(TextEdit::replace(range, header));
+                }
+            };
+            item.kind(completion_kind);
+            item.add_to(acc);
+        }
     }
 }
 
+/// Transform a relevant associated item to inline generics from the impl, remove attrs and docs, etc.
+fn get_transformed_assoc_item(
+    ctx: &CompletionContext,
+    assoc_item: ast::AssocItem,
+    impl_def: hir::Impl,
+) -> Option<ast::AssocItem> {
+    let assoc_item = assoc_item.clone_for_update();
+    let trait_ = impl_def.trait_(ctx.db)?;
+    let source_scope = &ctx.sema.scope_for_def(trait_);
+    let target_scope = &ctx.sema.scope(impl_def.source(ctx.db)?.syntax().value);
+    let transform = PathTransform {
+        subst: (trait_, impl_def.source(ctx.db)?.value),
+        source_scope,
+        target_scope,
+    };
+
+    transform.apply(assoc_item.clone());
+    Some(match assoc_item {
+        ast::AssocItem::Fn(func) => ast::AssocItem::Fn(edit::remove_attrs_and_docs(&func)),
+        _ => assoc_item,
+    })
+}
+
 fn add_type_alias_impl(
     type_def_node: &SyntaxNode,
     acc: &mut Completions,
@@ -188,21 +223,30 @@ fn add_const_impl(
     acc: &mut Completions,
     ctx: &CompletionContext,
     const_: hir::Const,
+    impl_def: hir::Impl,
 ) {
     let const_name = const_.name(ctx.db).map(|n| n.to_string());
 
     if let Some(const_name) = const_name {
         if let Some(source) = const_.source(ctx.db) {
-            let snippet = make_const_compl_syntax(&source.value);
-
-            let range = replacement_range(ctx, const_def_node);
-            let mut item =
-                CompletionItem::new(CompletionKind::Magic, ctx.source_range(), snippet.clone());
-            item.text_edit(TextEdit::replace(range, snippet))
-                .lookup_by(const_name)
-                .kind(SymbolKind::Const)
-                .set_documentation(const_.docs(ctx.db));
-            item.add_to(acc);
+            let assoc_item = ast::AssocItem::Const(source.value);
+            if let Some(transformed_item) = get_transformed_assoc_item(ctx, assoc_item, impl_def) {
+                let transformed_const = match transformed_item {
+                    ast::AssocItem::Const(const_) => const_,
+                    _ => unreachable!(),
+                };
+
+                let snippet = make_const_compl_syntax(&transformed_const);
+
+                let range = replacement_range(ctx, const_def_node);
+                let mut item =
+                    CompletionItem::new(CompletionKind::Magic, ctx.source_range(), snippet.clone());
+                item.text_edit(TextEdit::replace(range, snippet))
+                    .lookup_by(const_name)
+                    .kind(SymbolKind::Const)
+                    .set_documentation(const_.docs(ctx.db));
+                item.add_to(acc);
+            }
         }
     }
 }
@@ -246,12 +290,12 @@ mod tests {
     use expect_test::{expect, Expect};
 
     use crate::{
-        test_utils::{check_edit, completion_list},
+        tests::{check_edit, filtered_completion_list},
         CompletionKind,
     };
 
     fn check(ra_fixture: &str, expect: Expect) {
-        let actual = completion_list(ra_fixture, CompletionKind::Magic);
+        let actual = filtered_completion_list(ra_fixture, CompletionKind::Magic);
         expect.assert_eq(&actual)
     }
 
@@ -779,4 +823,183 @@ impl Foo for T {{
         test("Type", "type T$0", "type Type = ");
         test("CONST", "const C$0", "const CONST: i32 = ");
     }
+
+    #[test]
+    fn generics_are_inlined_in_return_type() {
+        check_edit(
+            "function",
+            r#"
+trait Foo<T> {
+    fn function() -> T;
+}
+struct Bar;
+
+impl Foo<u32> for Bar {
+    fn f$0
+}
+"#,
+            r#"
+trait Foo<T> {
+    fn function() -> T;
+}
+struct Bar;
+
+impl Foo<u32> for Bar {
+    fn function() -> u32 {
+    $0
+}
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn generics_are_inlined_in_parameter() {
+        check_edit(
+            "function",
+            r#"
+trait Foo<T> {
+    fn function(bar: T);
+}
+struct Bar;
+
+impl Foo<u32> for Bar {
+    fn f$0
+}
+"#,
+            r#"
+trait Foo<T> {
+    fn function(bar: T);
+}
+struct Bar;
+
+impl Foo<u32> for Bar {
+    fn function(bar: u32) {
+    $0
+}
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn generics_are_inlined_when_part_of_other_types() {
+        check_edit(
+            "function",
+            r#"
+trait Foo<T> {
+    fn function(bar: Vec<T>);
+}
+struct Bar;
+
+impl Foo<u32> for Bar {
+    fn f$0
+}
+"#,
+            r#"
+trait Foo<T> {
+    fn function(bar: Vec<T>);
+}
+struct Bar;
+
+impl Foo<u32> for Bar {
+    fn function(bar: Vec<u32>) {
+    $0
+}
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn generics_are_inlined_complex() {
+        check_edit(
+            "function",
+            r#"
+trait Foo<T, U, V> {
+    fn function(bar: Vec<T>, baz: U) -> Arc<Vec<V>>;
+}
+struct Bar;
+
+impl Foo<u32, Vec<usize>, u8> for Bar {
+    fn f$0
+}
+"#,
+            r#"
+trait Foo<T, U, V> {
+    fn function(bar: Vec<T>, baz: U) -> Arc<Vec<V>>;
+}
+struct Bar;
+
+impl Foo<u32, Vec<usize>, u8> for Bar {
+    fn function(bar: Vec<u32>, baz: Vec<usize>) -> Arc<Vec<u8>> {
+    $0
+}
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn generics_are_inlined_in_associated_const() {
+        check_edit(
+            "BAR",
+            r#"
+trait Foo<T> {
+    const BAR: T;
+}
+struct Bar;
+
+impl Foo<u32> for Bar {
+    const B$0;
+}
+"#,
+            r#"
+trait Foo<T> {
+    const BAR: T;
+}
+struct Bar;
+
+impl Foo<u32> for Bar {
+    const BAR: u32 = ;
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn generics_are_inlined_in_where_clause() {
+        check_edit(
+            "function",
+            r#"
+trait SomeTrait<T> {}
+
+trait Foo<T> {
+    fn function()
+    where Self: SomeTrait<T>;
+}
+struct Bar;
+
+impl Foo<u32> for Bar {
+    fn f$0
+}
+"#,
+            r#"
+trait SomeTrait<T> {}
+
+trait Foo<T> {
+    fn function()
+    where Self: SomeTrait<T>;
+}
+struct Bar;
+
+impl Foo<u32> for Bar {
+    fn function()
+where Self: SomeTrait<u32> {
+    $0
+}
+}
+"#,
+        )
+    }
 }
diff --git a/crates/ide_completion/src/completions/unqualified_path.rs b/crates/ide_completion/src/completions/unqualified_path.rs
index 952f052a1..380c1e079 100644
--- a/crates/ide_completion/src/completions/unqualified_path.rs
+++ b/crates/ide_completion/src/completions/unqualified_path.rs
@@ -6,7 +6,7 @@ use syntax::{ast, AstNode};
 use crate::{patterns::ImmediateLocation, CompletionContext, Completions};
 
 pub(crate) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionContext) {
-    if ctx.is_path_disallowed() || !ctx.is_trivial_path() {
+    if ctx.is_path_disallowed() || !ctx.is_trivial_path() || ctx.has_impl_or_trait_prev_sibling() {
         return;
     }
 
@@ -25,7 +25,7 @@ pub(crate) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionC
         return;
     }
 
-    if ctx.expects_use_tree() {
+    if ctx.in_use_tree() {
         // only show modules in a fresh UseTree
         cov_mark::hit!(only_completes_modules_in_import);
         ctx.scope.process_all_names(&mut |name, res| {
@@ -36,12 +36,14 @@ pub(crate) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionC
         return;
     }
 
-    if let Some(hir::Adt::Enum(e)) =
-        ctx.expected_type.as_ref().and_then(|ty| ty.strip_references().as_adt())
-    {
-        super::complete_enum_variants(acc, ctx, e, |acc, ctx, variant, path| {
-            acc.add_qualified_enum_variant(ctx, variant, path)
-        });
+    if !ctx.expects_type() {
+        if let Some(hir::Adt::Enum(e)) =
+            ctx.expected_type.as_ref().and_then(|ty| ty.strip_references().as_adt())
+        {
+            super::enum_variants_with_paths(acc, ctx, e, |acc, ctx, variant, path| {
+                acc.add_qualified_enum_variant(ctx, variant, path)
+            });
+        }
     }
 
     if let Some(ImmediateLocation::GenericArgList(arg_list)) = &ctx.completion_location {
@@ -59,12 +61,30 @@ pub(crate) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionC
     }
 
     ctx.scope.process_all_names(&mut |name, res| {
-        if let ScopeDef::GenericParam(hir::GenericParam::LifetimeParam(_)) = res {
+        if let ScopeDef::GenericParam(hir::GenericParam::LifetimeParam(_)) | ScopeDef::Label(_) =
+            res
+        {
             cov_mark::hit!(skip_lifetime_completion);
             return;
         }
         let add_resolution = match res {
+            ScopeDef::ImplSelfType(_) => {
+                !ctx.previous_token_is(syntax::T![impl]) && !ctx.previous_token_is(syntax::T![for])
+            }
+            // Don't suggest attribute macros and derives.
             ScopeDef::MacroDef(mac) => mac.is_fn_like(),
+            // no values in type places
+            ScopeDef::ModuleDef(
+                hir::ModuleDef::Function(_)
+                | hir::ModuleDef::Variant(_)
+                | hir::ModuleDef::Static(_),
+            )
+            | ScopeDef::Local(_) => !ctx.expects_type(),
+            // unless its a constant in a generic arg list position
+            ScopeDef::ModuleDef(hir::ModuleDef::Const(_))
+            | ScopeDef::GenericParam(hir::GenericParam::ConstParam(_)) => {
+                !ctx.expects_type() || ctx.expects_generic_arg()
+            }
             _ => true,
         };
         if add_resolution {
@@ -78,7 +98,7 @@ mod tests {
     use expect_test::{expect, Expect};
 
     use crate::{
-        test_utils::{check_edit, completion_list_with_config, TEST_CONFIG},
+        tests::{check_edit, filtered_completion_list_with_config, TEST_CONFIG},
         CompletionConfig, CompletionKind,
     };
 
@@ -87,99 +107,12 @@ mod tests {
     }
 
     fn check_with_config(config: CompletionConfig, ra_fixture: &str, expect: Expect) {
-        let actual = completion_list_with_config(config, ra_fixture, CompletionKind::Reference);
+        let actual =
+            filtered_completion_list_with_config(config, ra_fixture, CompletionKind::Reference);
         expect.assert_eq(&actual)
     }
 
     #[test]
-    fn dont_complete_values_in_type_pos() {
-        check(
-            r#"
-const FOO: () = ();
-static BAR: () = ();
-enum Foo {
-    Bar
-}
-struct Baz;
-fn foo() {
-    let local = ();
-    let _: $0;
-}
-"#,
-            expect![[r#"
-                en Foo
-                st Baz
-            "#]],
-        );
-    }
-
-    #[test]
-    fn only_completes_modules_in_import() {
-        cov_mark::check!(only_completes_modules_in_import);
-        check(
-            r#"
-use f$0
-
-struct Foo;
-mod foo {}
-"#,
-            expect![[r#"
-                md foo
-            "#]],
-        );
-    }
-
-    #[test]
-    fn bind_pat_and_path_ignore_at() {
-        check(
-            r#"
-enum Enum { A, B }
-fn quux(x: Option<Enum>) {
-    match x {
-        None => (),
-        Some(en$0 @ Enum::A) => (),
-    }
-}
-"#,
-            expect![[r#""#]],
-        );
-    }
-
-    #[test]
-    fn bind_pat_and_path_ignore_ref() {
-        check(
-            r#"
-enum Enum { A, B }
-fn quux(x: Option<Enum>) {
-    match x {
-        None => (),
-        Some(ref en$0) => (),
-    }
-}
-"#,
-            expect![[r#""#]],
-        );
-    }
-
-    #[test]
-    fn bind_pat_and_path() {
-        check(
-            r#"
-enum Enum { A, B }
-fn quux(x: Option<Enum>) {
-    match x {
-        None => (),
-        Some(En$0) => (),
-    }
-}
-"#,
-            expect![[r#"
-                en Enum
-            "#]],
-        );
-    }
-
-    #[test]
     fn completes_bindings_from_let() {
         check(
             r#"
@@ -284,29 +217,6 @@ fn main() {
     }
 
     #[test]
-    fn completes_generic_params_in_struct() {
-        check(
-            r#"struct S<T> { x: $0}"#,
-            expect![[r#"
-                sp Self
-                tp T
-                st S<…>
-            "#]],
-        );
-    }
-
-    #[test]
-    fn completes_self_in_enum() {
-        check(
-            r#"enum X { Y($0) }"#,
-            expect![[r#"
-                sp Self
-                en X
-            "#]],
-        );
-    }
-
-    #[test]
     fn completes_module_items() {
         check(
             r#"
@@ -343,22 +253,6 @@ fn _alpha() {}
     }
 
     #[test]
-    fn completes_extern_prelude() {
-        check(
-            r#"
-//- /lib.rs crate:main deps:other_crate
-use $0;
-
-//- /other_crate/lib.rs crate:other_crate
-// nothing here
-"#,
-            expect![[r#"
-                md other_crate
-            "#]],
-        );
-    }
-
-    #[test]
     fn completes_module_items_in_nested_modules() {
         check(
             r#"
@@ -376,19 +270,6 @@ mod m {
     }
 
     #[test]
-    fn completes_return_type() {
-        check(
-            r#"
-struct Foo;
-fn x() -> $0
-"#,
-            expect![[r#"
-                st Foo
-            "#]],
-        );
-    }
-
-    #[test]
     fn dont_show_both_completions_for_shadowing() {
         check(
             r#"
@@ -485,18 +366,6 @@ fn f() {$0}
         check(
             r#"
 #[rustc_builtin_macro]
-pub macro Clone {}
-
-struct S;
-impl S {
-    $0
-}
-"#,
-            expect![[r#""#]],
-        );
-        check(
-            r#"
-#[rustc_builtin_macro]
 pub macro bench {}
 
 fn f() {$0}
@@ -582,19 +451,6 @@ fn foo() { $0 }
     }
 
     #[test]
-    fn completes_macros_as_type() {
-        check(
-            r#"
-macro_rules! foo { () => {} }
-fn main() { let x: $0 }
-"#,
-            expect![[r#"
-                ma foo!(…) macro_rules! foo
-            "#]],
-        );
-    }
-
-    #[test]
     fn completes_macros_as_stmt() {
         check(
             r#"
@@ -739,74 +595,4 @@ fn f() {}
             expect![[""]],
         )
     }
-
-    #[test]
-    fn completes_target_type_or_trait_in_impl_block() {
-        check(
-            r#"
-trait MyTrait {}
-struct MyStruct {}
-
-impl My$0
-"#,
-            expect![[r#"
-                sp Self
-                tt MyTrait
-                st MyStruct
-            "#]],
-        )
-    }
-
-    #[test]
-    fn completes_in_assoc_item_list() {
-        check(
-            r#"
-macro_rules! foo {}
-mod bar {}
-
-struct MyStruct {}
-impl MyStruct {
-    $0
-}
-"#,
-            expect![[r#"
-                md bar
-                ma foo!(…) macro_rules! foo
-            "#]],
-        )
-    }
-
-    #[test]
-    fn completes_in_item_list() {
-        check(
-            r#"
-struct MyStruct {}
-macro_rules! foo {}
-mod bar {}
-
-$0
-"#,
-            expect![[r#"
-                md bar
-                ma foo!(…) macro_rules! foo
-            "#]],
-        )
-    }
-
-    #[test]
-    fn completes_assoc_types_in_dynimpl_trait() {
-        check(
-            r#"
-trait Foo {
-    type Bar;
-}
-
-fn foo(_: impl Foo<B$0>) {}
-"#,
-            expect![[r#"
-                ta Bar =  type Bar;
-                tt Foo
-            "#]],
-        );
-    }
 }
diff --git a/crates/ide_completion/src/context.rs b/crates/ide_completion/src/context.rs
index 4c3929a26..f0da98739 100644
--- a/crates/ide_completion/src/context.rs
+++ b/crates/ide_completion/src/context.rs
@@ -43,6 +43,8 @@ pub(crate) struct PathCompletionContext {
     pub(super) is_trivial_path: bool,
     /// If not a trivial path, the prefix (qualifier).
     pub(super) qualifier: Option<ast::Path>,
+    /// Whether the qualifier comes from a use tree parent or not
+    pub(super) use_tree_parent: bool,
     pub(super) kind: Option<PathKind>,
     /// Whether the path segment has type args or not.
     pub(super) has_type_args: bool,
@@ -79,7 +81,6 @@ pub(crate) struct CompletionContext<'a> {
     /// The parent impl of the cursor position if it exists.
     pub(super) impl_def: Option<ast::Impl>,
     pub(super) name_ref_syntax: Option<ast::NameRef>,
-    pub(super) use_item_syntax: Option<ast::Use>,
 
     // potentially set if we are completing a lifetime
     pub(super) lifetime_syntax: Option<ast::Lifetime>,
@@ -151,7 +152,6 @@ impl<'a> CompletionContext<'a> {
             function_def: None,
             impl_def: None,
             name_ref_syntax: None,
-            use_item_syntax: None,
             lifetime_syntax: None,
             lifetime_param_syntax: None,
             lifetime_allowed: false,
@@ -242,32 +242,27 @@ impl<'a> CompletionContext<'a> {
     }
 
     pub(crate) fn expects_assoc_item(&self) -> bool {
-        matches!(
-            self.completion_location,
-            Some(ImmediateLocation::Trait) | Some(ImmediateLocation::Impl)
-        )
+        matches!(self.completion_location, Some(ImmediateLocation::Trait | ImmediateLocation::Impl))
     }
 
     pub(crate) fn has_dot_receiver(&self) -> bool {
         matches!(
             &self.completion_location,
-            Some(ImmediateLocation::FieldAccess { receiver, .. }) | Some(ImmediateLocation::MethodCall { receiver,.. })
+            Some(ImmediateLocation::FieldAccess { receiver, .. } | ImmediateLocation::MethodCall { receiver,.. })
                 if receiver.is_some()
         )
     }
 
     pub(crate) fn dot_receiver(&self) -> Option<&ast::Expr> {
         match &self.completion_location {
-            Some(ImmediateLocation::MethodCall { receiver, .. })
-            | Some(ImmediateLocation::FieldAccess { receiver, .. }) => receiver.as_ref(),
+            Some(
+                ImmediateLocation::MethodCall { receiver, .. }
+                | ImmediateLocation::FieldAccess { receiver, .. },
+            ) => receiver.as_ref(),
             _ => None,
         }
     }
 
-    pub(crate) fn expects_use_tree(&self) -> bool {
-        matches!(self.completion_location, Some(ImmediateLocation::Use))
-    }
-
     pub(crate) fn expects_non_trait_assoc_item(&self) -> bool {
         matches!(self.completion_location, Some(ImmediateLocation::Impl))
     }
@@ -276,6 +271,10 @@ impl<'a> CompletionContext<'a> {
         matches!(self.completion_location, Some(ImmediateLocation::ItemList))
     }
 
+    pub(crate) fn expects_generic_arg(&self) -> bool {
+        matches!(self.completion_location, Some(ImmediateLocation::GenericArgList(_)))
+    }
+
     pub(crate) fn has_block_expr_parent(&self) -> bool {
         matches!(self.completion_location, Some(ImmediateLocation::BlockExpr))
     }
@@ -283,33 +282,59 @@ impl<'a> CompletionContext<'a> {
     pub(crate) fn expects_ident_pat_or_ref_expr(&self) -> bool {
         matches!(
             self.completion_location,
-            Some(ImmediateLocation::IdentPat) | Some(ImmediateLocation::RefExpr)
+            Some(ImmediateLocation::IdentPat | ImmediateLocation::RefExpr)
         )
     }
 
-    pub(crate) fn expect_record_field(&self) -> bool {
-        matches!(self.completion_location, Some(ImmediateLocation::RecordField))
+    pub(crate) fn expect_field(&self) -> bool {
+        matches!(
+            self.completion_location,
+            Some(ImmediateLocation::RecordField | ImmediateLocation::TupleField)
+        )
+    }
+
+    pub(crate) fn in_use_tree(&self) -> bool {
+        matches!(
+            self.completion_location,
+            Some(ImmediateLocation::Use | ImmediateLocation::UseTree)
+        )
     }
 
     pub(crate) fn has_impl_or_trait_prev_sibling(&self) -> bool {
         matches!(
             self.prev_sibling,
-            Some(ImmediatePrevSibling::ImplDefType) | Some(ImmediatePrevSibling::TraitDefName)
+            Some(ImmediatePrevSibling::ImplDefType | ImmediatePrevSibling::TraitDefName)
         )
     }
 
+    pub(crate) fn has_impl_prev_sibling(&self) -> bool {
+        matches!(self.prev_sibling, Some(ImmediatePrevSibling::ImplDefType))
+    }
+
+    pub(crate) fn has_visibility_prev_sibling(&self) -> bool {
+        matches!(self.prev_sibling, Some(ImmediatePrevSibling::Visibility))
+    }
+
     pub(crate) fn after_if(&self) -> bool {
         matches!(self.prev_sibling, Some(ImmediatePrevSibling::IfExpr))
     }
 
     pub(crate) fn is_path_disallowed(&self) -> bool {
-        matches!(
-            self.completion_location,
-            Some(ImmediateLocation::Attribute(_))
-                | Some(ImmediateLocation::ModDeclaration(_))
-                | Some(ImmediateLocation::RecordPat(_))
-                | Some(ImmediateLocation::RecordExpr(_))
-        ) || self.attribute_under_caret.is_some()
+        self.attribute_under_caret.is_some()
+            || self.previous_token_is(T![unsafe])
+            || matches!(
+                self.prev_sibling,
+                Some(ImmediatePrevSibling::Attribute | ImmediatePrevSibling::Visibility)
+            )
+            || matches!(
+                self.completion_location,
+                Some(
+                    ImmediateLocation::Attribute(_)
+                        | ImmediateLocation::ModDeclaration(_)
+                        | ImmediateLocation::RecordPat(_)
+                        | ImmediateLocation::RecordExpr(_)
+                )
+            )
     }
 
     pub(crate) fn expects_expression(&self) -> bool {
@@ -363,14 +388,19 @@ impl<'a> CompletionContext<'a> {
                         (ty, name)
                     },
                     ast::ArgList(_it) => {
-                        cov_mark::hit!(expected_type_fn_param_with_leading_char);
-                        cov_mark::hit!(expected_type_fn_param_without_leading_char);
+                        cov_mark::hit!(expected_type_fn_param);
                         ActiveParameter::at_token(
                             &self.sema,
                             self.token.clone(),
                         ).map(|ap| {
                             let name = ap.ident().map(NameOrNameRef::Name);
-                            (Some(ap.ty), name)
+                            let ty = if has_ref(&self.token) {
+                                cov_mark::hit!(expected_type_fn_param_ref);
+                                ap.ty.remove_ref()
+                            } else {
+                                Some(ap.ty)
+                            };
+                            (ty, name)
                         })
                         .unwrap_or((None, None))
                     },
@@ -564,9 +594,6 @@ impl<'a> CompletionContext<'a> {
         self.name_ref_syntax =
             find_node_at_offset(original_file, name_ref.syntax().text_range().start());
 
-        self.use_item_syntax =
-            self.sema.token_ancestors_with_macros(self.token.clone()).find_map(ast::Use::cast);
-
         self.function_def = self
             .sema
             .token_ancestors_with_macros(self.token.clone())
@@ -586,6 +613,7 @@ impl<'a> CompletionContext<'a> {
                 has_type_args: false,
                 can_be_stmt: false,
                 in_loop_body: false,
+                use_tree_parent: false,
                 kind: None,
             });
             path_ctx.in_loop_body = is_in_loop_body(name_ref.syntax());
@@ -613,7 +641,8 @@ impl<'a> CompletionContext<'a> {
             }
             path_ctx.has_type_args = segment.generic_arg_list().is_some();
 
-            if let Some(path) = path_or_use_tree_qualifier(&path) {
+            if let Some((path, use_tree_parent)) = path_or_use_tree_qualifier(&path) {
+                path_ctx.use_tree_parent = use_tree_parent;
                 path_ctx.qualifier = path
                     .segment()
                     .and_then(|it| {
@@ -667,13 +696,26 @@ fn is_node<N: AstNode>(node: &SyntaxNode) -> bool {
     }
 }
 
-fn path_or_use_tree_qualifier(path: &ast::Path) -> Option<ast::Path> {
+fn path_or_use_tree_qualifier(path: &ast::Path) -> Option<(ast::Path, bool)> {
     if let Some(qual) = path.qualifier() {
-        return Some(qual);
+        return Some((qual, false));
     }
     let use_tree_list = path.syntax().ancestors().find_map(ast::UseTreeList::cast)?;
     let use_tree = use_tree_list.syntax().parent().and_then(ast::UseTree::cast)?;
-    use_tree.path()
+    use_tree.path().zip(Some(true))
+}
+
+fn has_ref(token: &SyntaxToken) -> bool {
+    let mut token = token.clone();
+    for skip in [WHITESPACE, IDENT, T![mut]] {
+        if token.kind() == skip {
+            token = match token.prev_token() {
+                Some(it) => it,
+                None => return false,
+            }
+        }
+    }
+    token.kind() == T![&]
 }
 
 #[cfg(test)]
@@ -681,7 +723,7 @@ mod tests {
     use expect_test::{expect, Expect};
     use hir::HirDisplay;
 
-    use crate::test_utils::{position, TEST_CONFIG};
+    use crate::tests::{position, TEST_CONFIG};
 
     use super::CompletionContext;
 
@@ -748,14 +790,18 @@ fn foo() {
     }
 
     #[test]
-    fn expected_type_fn_param_without_leading_char() {
-        cov_mark::check!(expected_type_fn_param_without_leading_char);
+    fn expected_type_fn_param() {
+        cov_mark::check!(expected_type_fn_param);
         check_expected_type_and_name(
             r#"
-fn foo() {
-    bar($0);
-}
-
+fn foo() { bar($0); }
+fn bar(x: u32) {}
+"#,
+            expect![[r#"ty: u32, name: x"#]],
+        );
+        check_expected_type_and_name(
+            r#"
+fn foo() { bar(c$0); }
 fn bar(x: u32) {}
 "#,
             expect![[r#"ty: u32, name: x"#]],
@@ -763,18 +809,29 @@ fn bar(x: u32) {}
     }
 
     #[test]
-    fn expected_type_fn_param_with_leading_char() {
-        cov_mark::check!(expected_type_fn_param_with_leading_char);
+    fn expected_type_fn_param_ref() {
+        cov_mark::check!(expected_type_fn_param_ref);
         check_expected_type_and_name(
             r#"
-fn foo() {
-    bar(c$0);
-}
-
-fn bar(x: u32) {}
+fn foo() { bar(&$0); }
+fn bar(x: &u32) {}
+"#,
+            expect![[r#"ty: u32, name: x"#]],
+        );
+        check_expected_type_and_name(
+            r#"
+fn foo() { bar(&mut $0); }
+fn bar(x: &mut u32) {}
 "#,
             expect![[r#"ty: u32, name: x"#]],
         );
+        check_expected_type_and_name(
+            r#"
+fn foo() { bar(&c$0); }
+fn bar(x: &u32) {}
+        "#,
+            expect![[r#"ty: u32, name: x"#]],
+        );
     }
 
     #[test]
@@ -921,13 +978,12 @@ fn foo() -> u32 {
         // FIXME: make this work with `|| $0`
         check_expected_type_and_name(
             r#"
+//- minicore: fn
 fn foo() {
     bar(|| a$0);
 }
 
 fn bar(f: impl FnOnce() -> u32) {}
-#[lang = "fn_once"]
-trait FnOnce { type Output; }
 "#,
             expect![[r#"ty: u32, name: ?"#]],
         );
diff --git a/crates/ide_completion/src/item.rs b/crates/ide_completion/src/item.rs
index 99edb9499..ae63d132e 100644
--- a/crates/ide_completion/src/item.rs
+++ b/crates/ide_completion/src/item.rs
@@ -378,7 +378,7 @@ impl ImportEdit {
         let _p = profile::span("ImportEdit::to_text_edit");
 
         let new_ast = self.scope.clone_for_update();
-        insert_use::insert_use(&new_ast, mod_path_to_ast(&self.import.import_path), cfg);
+        insert_use::insert_use(&new_ast, mod_path_to_ast(&self.import.import_path), &cfg);
         let mut import_insert = TextEdit::builder();
         algo::diff(self.scope.as_syntax_node(), new_ast.as_syntax_node())
             .into_text_edit(&mut import_insert);
diff --git a/crates/ide_completion/src/lib.rs b/crates/ide_completion/src/lib.rs
index 18983aa01..bf73818dc 100644
--- a/crates/ide_completion/src/lib.rs
+++ b/crates/ide_completion/src/lib.rs
@@ -1,14 +1,14 @@
 //! `completions` crate provides utilities for generating completions of user input.
 
+mod completions;
 mod config;
-mod item;
 mod context;
+mod item;
 mod patterns;
-#[cfg(test)]
-mod test_utils;
 mod render;
 
-mod completions;
+#[cfg(test)]
+mod tests;
 
 use completions::flyimport::position_for_import;
 use ide_db::{
@@ -141,6 +141,7 @@ pub fn completions(
     let ctx = CompletionContext::new(db, position, config)?;
 
     if ctx.no_completion_required() {
+        cov_mark::hit!(no_completion_required);
         // No work required here.
         return None;
     }
@@ -200,117 +201,3 @@ pub fn resolve_completion_edits(
 
     ImportEdit { import, scope }.to_text_edit(config.insert_use).map(|edit| vec![edit])
 }
-
-#[cfg(test)]
-mod tests {
-    use crate::test_utils::{self, TEST_CONFIG};
-
-    struct DetailAndDocumentation<'a> {
-        detail: &'a str,
-        documentation: &'a str,
-    }
-
-    fn check_detail_and_documentation(ra_fixture: &str, expected: DetailAndDocumentation) {
-        let (db, position) = test_utils::position(ra_fixture);
-        let config = TEST_CONFIG;
-        let completions: Vec<_> = crate::completions(&db, &config, position).unwrap().into();
-        for item in completions {
-            if item.detail() == Some(expected.detail) {
-                let opt = item.documentation();
-                let doc = opt.as_ref().map(|it| it.as_str());
-                assert_eq!(doc, Some(expected.documentation));
-                return;
-            }
-        }
-        panic!("completion detail not found: {}", expected.detail)
-    }
-
-    fn check_no_completion(ra_fixture: &str) {
-        let (db, position) = test_utils::position(ra_fixture);
-        let config = TEST_CONFIG;
-
-        let completions: Option<Vec<String>> = crate::completions(&db, &config, position)
-            .and_then(|completions| {
-                let completions: Vec<_> = completions.into();
-                if completions.is_empty() {
-                    None
-                } else {
-                    Some(completions)
-                }
-            })
-            .map(|completions| {
-                completions.into_iter().map(|completion| format!("{:?}", completion)).collect()
-            });
-
-        // `assert_eq` instead of `assert!(completions.is_none())` to get the list of completions if test will panic.
-        assert_eq!(completions, None, "Completions were generated, but weren't expected");
-    }
-
-    #[test]
-    fn test_completion_detail_from_macro_generated_struct_fn_doc_attr() {
-        check_detail_and_documentation(
-            r#"
-macro_rules! bar {
-    () => {
-        struct Bar;
-        impl Bar {
-            #[doc = "Do the foo"]
-            fn foo(&self) {}
-        }
-    }
-}
-
-bar!();
-
-fn foo() {
-    let bar = Bar;
-    bar.fo$0;
-}
-"#,
-            DetailAndDocumentation { detail: "fn(&self)", documentation: "Do the foo" },
-        );
-    }
-
-    #[test]
-    fn test_completion_detail_from_macro_generated_struct_fn_doc_comment() {
-        check_detail_and_documentation(
-            r#"
-macro_rules! bar {
-    () => {
-        struct Bar;
-        impl Bar {
-            /// Do the foo
-            fn foo(&self) {}
-        }
-    }
-}
-
-bar!();
-
-fn foo() {
-    let bar = Bar;
-    bar.fo$0;
-}
-"#,
-            DetailAndDocumentation { detail: "fn(&self)", documentation: "Do the foo" },
-        );
-    }
-
-    #[test]
-    fn test_no_completions_required() {
-        // There must be no hint for 'in' keyword.
-        check_no_completion(r#"fn foo() { for i i$0 }"#);
-        // After 'in' keyword hints may be spawned.
-        check_detail_and_documentation(
-            r#"
-/// Do the foo
-fn foo() -> &'static str { "foo" }
-
-fn bar() {
-    for c in fo$0
-}
-"#,
-            DetailAndDocumentation { detail: "fn() -> &str", documentation: "Do the foo" },
-        );
-    }
-}
diff --git a/crates/ide_completion/src/patterns.rs b/crates/ide_completion/src/patterns.rs
index 72e67e3c4..757c9a3da 100644
--- a/crates/ide_completion/src/patterns.rs
+++ b/crates/ide_completion/src/patterns.rs
@@ -11,7 +11,7 @@ use syntax::{
 };
 
 #[cfg(test)]
-use crate::test_utils::{check_pattern_is_applicable, check_pattern_is_not_applicable};
+use crate::tests::{check_pattern_is_applicable, check_pattern_is_not_applicable};
 
 /// Immediate previous node to what we are completing.
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
@@ -19,15 +19,19 @@ pub(crate) enum ImmediatePrevSibling {
     IfExpr,
     TraitDefName,
     ImplDefType,
+    Visibility,
+    Attribute,
 }
 
 /// Direct parent "thing" of what we are currently completing.
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub(crate) enum ImmediateLocation {
     Use,
+    UseTree,
     Impl,
     Trait,
     RecordField,
+    TupleField,
     RefExpr,
     IdentPat,
     BlockExpr,
@@ -79,6 +83,17 @@ pub(crate) fn determine_prev_sibling(name_like: &ast::NameLike) -> Option<Immedi
         _ => node,
     };
     let prev_sibling = non_trivia_sibling(node.into(), Direction::Prev)?.into_node()?;
+    if prev_sibling.kind() == ERROR {
+        let prev_sibling = prev_sibling.first_child()?;
+        let res = match_ast! {
+            match prev_sibling {
+                // vis followed by random ident will always error the parser
+                ast::Visibility(_it) => ImmediatePrevSibling::Visibility,
+                _ => return None,
+            }
+        };
+        return Some(res);
+    }
     let res = match_ast! {
         match prev_sibling {
             ast::ExprStmt(it) => {
@@ -101,6 +116,7 @@ pub(crate) fn determine_prev_sibling(name_like: &ast::NameLike) -> Option<Immedi
                 } else {
                     return None
             },
+            ast::Attr(_it) => ImmediatePrevSibling::Attribute,
             _ => return None,
         }
     };
@@ -166,11 +182,19 @@ pub(crate) fn determine_location(
         match parent {
             ast::IdentPat(_it) => ImmediateLocation::IdentPat,
             ast::Use(_it) => ImmediateLocation::Use,
+            ast::UseTree(_it) => ImmediateLocation::UseTree,
+            ast::UseTreeList(_it) => ImmediateLocation::UseTree,
             ast::BlockExpr(_it) => ImmediateLocation::BlockExpr,
             ast::SourceFile(_it) => ImmediateLocation::ItemList,
             ast::ItemList(_it) => ImmediateLocation::ItemList,
             ast::RefExpr(_it) => ImmediateLocation::RefExpr,
-            ast::RecordField(_it) => ImmediateLocation::RecordField,
+            ast::RecordField(it) => if it.ty().map_or(false, |it| it.syntax().text_range().contains(offset)) {
+                return None;
+            } else {
+                ImmediateLocation::RecordField
+            },
+            ast::TupleField(_it) => ImmediateLocation::TupleField,
+            ast::TupleFieldList(_it) => ImmediateLocation::TupleField,
             ast::AssocItemList(it) => match it.syntax().parent().map(|it| it.kind()) {
                 Some(IMPL) => ImmediateLocation::Impl,
                 Some(TRAIT) => ImmediateLocation::Trait,
@@ -310,7 +334,7 @@ fn previous_non_trivia_token(token: SyntaxToken) -> Option<SyntaxToken> {
 mod tests {
     use syntax::algo::find_node_at_offset;
 
-    use crate::test_utils::position;
+    use crate::tests::position;
 
     use super::*;
 
@@ -359,8 +383,8 @@ mod tests {
     fn test_use_loc() {
         check_location(r"use f$0", ImmediateLocation::Use);
         check_location(r"use f$0;", ImmediateLocation::Use);
-        check_location(r"use f::{f$0}", None);
-        check_location(r"use {f$0}", None);
+        check_location(r"use f::{f$0}", ImmediateLocation::UseTree);
+        check_location(r"use {f$0}", ImmediateLocation::UseTree);
     }
 
     #[test]
@@ -421,4 +445,14 @@ mod tests {
         check_prev_sibling(r"fn foo() { if true {} w$0", ImmediatePrevSibling::IfExpr);
         check_prev_sibling(r"fn foo() { if true {}; w$0", None);
     }
+
+    #[test]
+    fn test_vis_prev_sibling() {
+        check_prev_sibling(r"pub w$0", ImmediatePrevSibling::Visibility);
+    }
+
+    #[test]
+    fn test_attr_prev_sibling() {
+        check_prev_sibling(r"#[attr] w$0", ImmediatePrevSibling::Attribute);
+    }
 }
diff --git a/crates/ide_completion/src/render.rs b/crates/ide_completion/src/render.rs
index d8ca18c73..1a9b6212a 100644
--- a/crates/ide_completion/src/render.rs
+++ b/crates/ide_completion/src/render.rs
@@ -23,53 +23,6 @@ use crate::{
     render::{enum_variant::render_variant, function::render_fn, macro_::render_macro},
     CompletionContext, CompletionItem, CompletionItemKind, CompletionKind, CompletionRelevance,
 };
-
-pub(crate) fn render_field(
-    ctx: RenderContext<'_>,
-    receiver: Option<hir::Name>,
-    field: hir::Field,
-    ty: &hir::Type,
-) -> CompletionItem {
-    render_field_(ctx, receiver, field, ty)
-}
-
-pub(crate) fn render_tuple_field(
-    ctx: RenderContext<'_>,
-    receiver: Option<hir::Name>,
-    field: usize,
-    ty: &hir::Type,
-) -> CompletionItem {
-    render_tuple_field_(ctx, receiver, field, ty)
-}
-
-pub(crate) fn render_resolution(
-    ctx: RenderContext<'_>,
-    local_name: hir::Name,
-    resolution: &hir::ScopeDef,
-) -> Option<CompletionItem> {
-    render_resolution_(ctx, local_name, None, resolution)
-}
-
-pub(crate) fn render_resolution_with_import(
-    ctx: RenderContext<'_>,
-    import_edit: ImportEdit,
-) -> Option<CompletionItem> {
-    let resolution = hir::ScopeDef::from(import_edit.import.original_item);
-    if ctx.completion.expects_type() && resolution.is_value_def() {
-        return None;
-    }
-    let local_name = match resolution {
-        hir::ScopeDef::ModuleDef(hir::ModuleDef::Function(f)) => f.name(ctx.completion.db),
-        hir::ScopeDef::ModuleDef(hir::ModuleDef::Const(c)) => c.name(ctx.completion.db)?,
-        hir::ScopeDef::ModuleDef(hir::ModuleDef::TypeAlias(t)) => t.name(ctx.completion.db),
-        _ => item_name(ctx.db(), import_edit.import.original_item)?,
-    };
-    render_resolution_(ctx, local_name, Some(import_edit), &resolution).map(|mut item| {
-        item.completion_kind = CompletionKind::Magic;
-        item
-    })
-}
-
 /// Interface for data and methods required for items rendering.
 #[derive(Debug)]
 pub(crate) struct RenderContext<'a> {
@@ -122,7 +75,7 @@ impl<'a> RenderContext<'a> {
     }
 }
 
-fn render_field_(
+pub(crate) fn render_field(
     ctx: RenderContext<'_>,
     receiver: Option<hir::Name>,
     field: hir::Field,
@@ -135,7 +88,6 @@ fn render_field_(
         ctx.source_range(),
         receiver.map_or_else(|| name.clone(), |receiver| format!("{}.{}", receiver, name)),
     );
-
     item.set_relevance(CompletionRelevance {
         type_match: compute_type_match(ctx.completion, ty),
         exact_name_match: compute_exact_name_match(ctx.completion, &name),
@@ -146,17 +98,15 @@ fn render_field_(
         .set_documentation(field.docs(ctx.db()))
         .set_deprecated(is_deprecated)
         .lookup_by(name);
-
     if let Some(_ref_match) = compute_ref_match(ctx.completion, ty) {
         // FIXME
         // For now we don't properly calculate the edits for ref match
         // completions on struct fields, so we've disabled them. See #8058.
     }
-
     item.build()
 }
 
-fn render_tuple_field_(
+pub(crate) fn render_tuple_field(
     ctx: RenderContext<'_>,
     receiver: Option<hir::Name>,
     field: usize,
@@ -167,14 +117,37 @@ fn render_tuple_field_(
         ctx.source_range(),
         receiver.map_or_else(|| field.to_string(), |receiver| format!("{}.{}", receiver, field)),
     );
-
     item.kind(SymbolKind::Field)
         .detail(ty.display(ctx.db()).to_string())
         .lookup_by(field.to_string());
-
     item.build()
 }
 
+pub(crate) fn render_resolution(
+    ctx: RenderContext<'_>,
+    local_name: hir::Name,
+    resolution: &hir::ScopeDef,
+) -> Option<CompletionItem> {
+    render_resolution_(ctx, local_name, None, resolution)
+}
+
+pub(crate) fn render_resolution_with_import(
+    ctx: RenderContext<'_>,
+    import_edit: ImportEdit,
+) -> Option<CompletionItem> {
+    let resolution = hir::ScopeDef::from(import_edit.import.original_item);
+    let local_name = match resolution {
+        hir::ScopeDef::ModuleDef(hir::ModuleDef::Function(f)) => f.name(ctx.completion.db),
+        hir::ScopeDef::ModuleDef(hir::ModuleDef::Const(c)) => c.name(ctx.completion.db)?,
+        hir::ScopeDef::ModuleDef(hir::ModuleDef::TypeAlias(t)) => t.name(ctx.completion.db),
+        _ => item_name(ctx.db(), import_edit.import.original_item)?,
+    };
+    render_resolution_(ctx, local_name, Some(import_edit), &resolution).map(|mut item| {
+        item.completion_kind = CompletionKind::Magic;
+        item
+    })
+}
+
 fn render_resolution_(
     ctx: RenderContext<'_>,
     local_name: hir::Name,
@@ -362,7 +335,7 @@ mod tests {
 
     use crate::{
         item::CompletionRelevanceTypeMatch,
-        test_utils::{check_edit, do_completion, get_all_items, TEST_CONFIG},
+        tests::{check_edit, do_completion, get_all_items, TEST_CONFIG},
         CompletionKind, CompletionRelevance,
     };
 
@@ -1084,7 +1057,7 @@ fn f() {
     #[test]
     fn suggest_ref_mut() {
         cov_mark::check!(suggest_ref);
-        check(
+        check_relevance(
             r#"
 struct S;
 fn foo(s: &mut S) {}
@@ -1094,74 +1067,40 @@ fn main() {
 }
             "#,
             expect![[r#"
-                [
-                    CompletionItem {
-                        label: "S",
-                        source_range: 70..70,
-                        delete: 70..70,
-                        insert: "S",
-                        kind: SymbolKind(
-                            Struct,
-                        ),
-                    },
-                    CompletionItem {
-                        label: "foo(…)",
-                        source_range: 70..70,
-                        delete: 70..70,
-                        insert: "foo(${1:&mut s})$0",
-                        kind: SymbolKind(
-                            Function,
-                        ),
-                        lookup: "foo",
-                        detail: "fn(&mut S)",
-                        trigger_call_info: true,
-                    },
-                    CompletionItem {
-                        label: "main()",
-                        source_range: 70..70,
-                        delete: 70..70,
-                        insert: "main()$0",
-                        kind: SymbolKind(
-                            Function,
-                        ),
-                        lookup: "main",
-                        detail: "fn()",
-                    },
-                    CompletionItem {
-                        label: "s",
-                        source_range: 70..70,
-                        delete: 70..70,
-                        insert: "s",
-                        kind: SymbolKind(
-                            Local,
-                        ),
-                        detail: "S",
-                        relevance: CompletionRelevance {
-                            exact_name_match: true,
-                            type_match: None,
-                            is_local: true,
-                        },
-                        ref_match: "&mut ",
-                    },
-                ]
+                lc s [name+local]
+                lc &mut s [type+name+local]
+                st S []
+                fn main() []
+                fn foo(…) []
             "#]],
-        )
+        );
+        check_relevance(
+            r#"
+struct S;
+fn foo(s: &mut S) {}
+fn main() {
+    let mut s = S;
+    foo(&mut $0);
+}
+            "#,
+            expect![[r#"
+                lc s [type+name+local]
+                st S []
+                fn main() []
+                fn foo(…) []
+            "#]],
+        );
     }
 
     #[test]
     fn suggest_deref() {
         check_relevance(
             r#"
-#[lang = "deref"]
-trait Deref {
-    type Target;
-    fn deref(&self) -> &Self::Target;
-}
-
+//- minicore: deref
 struct S;
 struct T(S);
 
-impl Deref for T {
+impl core::ops::Deref for T {
     type Target = S;
 
     fn deref(&self) -> &Self::Target {
@@ -1185,8 +1124,9 @@ fn main() {
                 st T []
                 st S []
                 fn main() []
-                tt Deref []
                 fn foo(…) []
+                md core []
+                tt Sized []
             "#]],
         )
     }
@@ -1195,21 +1135,11 @@ fn main() {
     fn suggest_deref_mut() {
         check_relevance(
             r#"
-#[lang = "deref"]
-trait Deref {
-    type Target;
-    fn deref(&self) -> &Self::Target;
-}
-
-#[lang = "deref_mut"]
-pub trait DerefMut: Deref {
-    fn deref_mut(&mut self) -> &mut Self::Target;
-}
-
+//- minicore: deref_mut
 struct S;
 struct T(S);
 
-impl Deref for T {
+impl core::ops::Deref for T {
     type Target = S;
 
     fn deref(&self) -> &Self::Target {
@@ -1217,7 +1147,7 @@ impl Deref for T {
     }
 }
 
-impl DerefMut for T {
+impl core::ops::DerefMut for T {
     fn deref_mut(&mut self) -> &mut Self::Target {
         &mut self.0
     }
@@ -1236,12 +1166,12 @@ fn main() {
                 lc m [local]
                 lc t [local]
                 lc &mut t [type+local]
-                tt DerefMut []
-                tt Deref []
-                fn foo(…) []
                 st T []
                 st S []
                 fn main() []
+                fn foo(…) []
+                md core []
+                tt Sized []
             "#]],
         )
     }
@@ -1310,16 +1240,11 @@ fn bar(t: &Foo) {}
     fn suggest_deref_fn_ret() {
         check_relevance(
             r#"
-#[lang = "deref"]
-trait Deref {
-    type Target;
-    fn deref(&self) -> &Self::Target;
-}
-
+//- minicore: deref
 struct S;
 struct T(S);
 
-impl Deref for T {
+impl core::ops::Deref for T {
     type Target = S;
 
     fn deref(&self) -> &Self::Target {
@@ -1333,15 +1258,16 @@ fn bar() -> T {}
 fn main() {
     foo($0);
 }
-            "#,
+"#,
             expect![[r#"
-                tt Deref []
-                fn bar() []
-                fn &bar() [type]
-                fn foo(…) []
                 st T []
                 st S []
                 fn main() []
+                fn bar() []
+                fn &bar() [type]
+                fn foo(…) []
+                md core []
+                tt Sized []
             "#]],
         )
     }
diff --git a/crates/ide_completion/src/render/builder_ext.rs b/crates/ide_completion/src/render/builder_ext.rs
index c54752d30..33d3a5ee1 100644
--- a/crates/ide_completion/src/render/builder_ext.rs
+++ b/crates/ide_completion/src/render/builder_ext.rs
@@ -28,11 +28,11 @@ impl Builder {
         if !ctx.config.add_call_parenthesis {
             return false;
         }
-        if ctx.use_item_syntax.is_some() {
+        if ctx.in_use_tree() {
             cov_mark::hit!(no_parens_in_use_item);
             return false;
         }
-        if matches!(ctx.path_call_kind(), Some(CallKind::Expr) | Some(CallKind::Pat))
+        if matches!(ctx.path_call_kind(), Some(CallKind::Expr | CallKind::Pat))
             | matches!(
                 ctx.completion_location,
                 Some(ImmediateLocation::MethodCall { has_parens: true, .. })
diff --git a/crates/ide_completion/src/render/enum_variant.rs b/crates/ide_completion/src/render/enum_variant.rs
index 28f056e77..91dc178f3 100644
--- a/crates/ide_completion/src/render/enum_variant.rs
+++ b/crates/ide_completion/src/render/enum_variant.rs
@@ -121,7 +121,7 @@ impl<'a> EnumRender<'a> {
 
 #[cfg(test)]
 mod tests {
-    use crate::test_utils::check_edit;
+    use crate::tests::check_edit;
 
     #[test]
     fn inserts_parens_for_tuple_enums() {
diff --git a/crates/ide_completion/src/render/function.rs b/crates/ide_completion/src/render/function.rs
index 1357b9f4a..19f2c86e9 100644
--- a/crates/ide_completion/src/render/function.rs
+++ b/crates/ide_completion/src/render/function.rs
@@ -191,7 +191,7 @@ impl<'a> FunctionRender<'a> {
 #[cfg(test)]
 mod tests {
     use crate::{
-        test_utils::{check_edit, check_edit_with_config, TEST_CONFIG},
+        tests::{check_edit, check_edit_with_config, TEST_CONFIG},
         CompletionConfig,
     };
 
diff --git a/crates/ide_completion/src/render/macro_.rs b/crates/ide_completion/src/render/macro_.rs
index 429d937c8..4d5179c4f 100644
--- a/crates/ide_completion/src/render/macro_.rs
+++ b/crates/ide_completion/src/render/macro_.rs
@@ -69,7 +69,7 @@ impl<'a> MacroRender<'a> {
     }
 
     fn needs_bang(&self) -> bool {
-        self.ctx.completion.use_item_syntax.is_none()
+        !self.ctx.completion.in_use_tree()
             && !matches!(self.ctx.completion.path_call_kind(), Some(CallKind::Mac))
     }
 
@@ -133,7 +133,7 @@ fn guess_macro_braces(macro_name: &str, docs: &str) -> (&'static str, &'static s
 
 #[cfg(test)]
 mod tests {
-    use crate::test_utils::check_edit;
+    use crate::tests::check_edit;
 
     #[test]
     fn dont_insert_macro_call_parens_unncessary() {
@@ -180,7 +180,7 @@ fn main() { frobnicate!(); }
 /// ```
 macro_rules! vec { () => {} }
 
-fn fn main() { v$0 }
+fn main() { v$0 }
 "#,
             r#"
 /// Creates a [`Vec`] containing the arguments.
@@ -193,7 +193,7 @@ fn fn main() { v$0 }
 /// ```
 macro_rules! vec { () => {} }
 
-fn fn main() { vec![$0] }
+fn main() { vec![$0] }
 "#,
         );
 
diff --git a/crates/ide_completion/src/test_utils.rs b/crates/ide_completion/src/tests.rs
index b0a4b2026..97298ff27 100644
--- a/crates/ide_completion/src/test_utils.rs
+++ b/crates/ide_completion/src/tests.rs
@@ -1,4 +1,16 @@
-//! Runs completion for testing purposes.
+//! Tests and test utilities for completions.
+//!
+//! Most tests live in this module or its submodules unless for very specific completions like
+//! `attributes` or `lifetimes` where the completed concept is a distinct thing.
+//! Notable examples for completions that are being tested in this module's submodule are paths.
+
+mod item_list;
+mod use_tree;
+mod items;
+mod pattern;
+mod type_pos;
+
+use std::mem;
 
 use hir::{PrefixKind, Semantics};
 use ide_db::{
@@ -28,9 +40,27 @@ pub(crate) const TEST_CONFIG: CompletionConfig = CompletionConfig {
         prefix_kind: PrefixKind::Plain,
         enforce_granularity: true,
         group: true,
+        skip_glob_imports: true,
     },
 };
 
+pub(crate) fn completion_list(code: &str) -> String {
+    completion_list_with_config(TEST_CONFIG, code)
+}
+
+fn completion_list_with_config(config: CompletionConfig, code: &str) -> String {
+    // filter out all but one builtintype completion for smaller test outputs
+    let items = get_all_items(config, code);
+    let mut bt_seen = false;
+    let items = items
+        .into_iter()
+        .filter(|it| {
+            it.completion_kind != CompletionKind::BuiltinType || !mem::replace(&mut bt_seen, true)
+        })
+        .collect();
+    render_completion_list(items)
+}
+
 /// Creates analysis from a multi-file fixture, returns positions marked with $0.
 pub(crate) fn position(ra_fixture: &str) -> (RootDatabase, FilePosition) {
     let change_fixture = ChangeFixture::parse(ra_fixture);
@@ -57,24 +87,27 @@ pub(crate) fn do_completion_with_config(
         .collect()
 }
 
-pub(crate) fn completion_list(code: &str, kind: CompletionKind) -> String {
-    completion_list_with_config(TEST_CONFIG, code, kind)
+pub(crate) fn filtered_completion_list(code: &str, kind: CompletionKind) -> String {
+    filtered_completion_list_with_config(TEST_CONFIG, code, kind)
 }
 
-pub(crate) fn completion_list_with_config(
+pub(crate) fn filtered_completion_list_with_config(
     config: CompletionConfig,
     code: &str,
     kind: CompletionKind,
 ) -> String {
     let kind_completions: Vec<CompletionItem> =
         get_all_items(config, code).into_iter().filter(|c| c.completion_kind == kind).collect();
-    let label_width = kind_completions
-        .iter()
-        .map(|it| monospace_width(it.label()))
-        .max()
-        .unwrap_or_default()
-        .min(16);
-    kind_completions
+    render_completion_list(kind_completions)
+}
+
+fn render_completion_list(completions: Vec<CompletionItem>) -> String {
+    fn monospace_width(s: &str) -> usize {
+        s.chars().count()
+    }
+    let label_width =
+        completions.iter().map(|it| monospace_width(it.label())).max().unwrap_or_default().min(16);
+    completions
         .into_iter()
         .map(|it| {
             let tag = it.kind().unwrap().tag();
@@ -93,10 +126,6 @@ pub(crate) fn completion_list_with_config(
         .collect()
 }
 
-fn monospace_width(s: &str) -> usize {
-    s.chars().count()
-}
-
 pub(crate) fn check_edit(what: &str, ra_fixture_before: &str, ra_fixture_after: &str) {
     check_edit_with_config(TEST_CONFIG, what, ra_fixture_before, ra_fixture_after)
 }
@@ -152,3 +181,18 @@ pub(crate) fn get_all_items(config: CompletionConfig, code: &str) -> Vec<Complet
     let (db, position) = position(code);
     crate::completions(&db, &config, position).unwrap().into()
 }
+
+fn check_no_completion(ra_fixture: &str) {
+    let (db, position) = position(ra_fixture);
+
+    assert!(
+        crate::completions(&db, &TEST_CONFIG, position).is_none(),
+        "Completions were generated, but weren't expected"
+    );
+}
+
+#[test]
+fn test_no_completions_required() {
+    cov_mark::check!(no_completion_required);
+    check_no_completion(r#"fn foo() { for i i$0 }"#);
+}
diff --git a/crates/ide_completion/src/tests/item_list.rs b/crates/ide_completion/src/tests/item_list.rs
new file mode 100644
index 000000000..7c124ac37
--- /dev/null
+++ b/crates/ide_completion/src/tests/item_list.rs
@@ -0,0 +1,223 @@
+use expect_test::{expect, Expect};
+
+use crate::tests::completion_list;
+
+fn check(ra_fixture: &str, expect: Expect) {
+    let base = r#"#[rustc_builtin_macro]
+pub macro Clone {}
+enum Enum { Variant }
+struct Struct {}
+#[macro_export]
+macro_rules! foo {}
+mod bar {}
+const CONST: () = ();
+trait Trait {}
+"#;
+    let actual = completion_list(&format!("{}{}", base, ra_fixture));
+    expect.assert_eq(&actual)
+}
+
+#[test]
+fn in_mod_item_list() {
+    check(
+        r#"mod tests { $0 }"#,
+        expect![[r##"
+            kw pub(crate)
+            kw pub
+            kw unsafe
+            kw fn
+            kw const
+            kw type
+            kw impl
+            kw extern
+            kw use
+            kw trait
+            kw static
+            kw mod
+            kw enum
+            kw struct
+            kw union
+            sn tmod (Test module)
+            sn tfn (Test function)
+            sn macro_rules
+            ma foo!(…)          #[macro_export] macro_rules! foo
+        "##]],
+    )
+}
+
+#[test]
+fn in_source_file_item_list() {
+    check(
+        r#"$0"#,
+        expect![[r##"
+            kw pub(crate)
+            kw pub
+            kw unsafe
+            kw fn
+            kw const
+            kw type
+            kw impl
+            kw extern
+            kw use
+            kw trait
+            kw static
+            kw mod
+            kw enum
+            kw struct
+            kw union
+            sn tmod (Test module)
+            sn tfn (Test function)
+            sn macro_rules
+            md bar
+            ma foo!(…)          #[macro_export] macro_rules! foo
+            ma foo!(…)          #[macro_export] macro_rules! foo
+        "##]],
+    )
+}
+
+#[test]
+fn in_item_list_after_attr() {
+    check(
+        r#"#[attr] $0"#,
+        expect![[r#"
+            kw pub(crate)
+            kw pub
+            kw unsafe
+            kw fn
+            kw const
+            kw type
+            kw impl
+            kw extern
+            kw use
+            kw trait
+            kw static
+            kw mod
+            kw enum
+            kw struct
+            kw union
+            sn tmod (Test module)
+            sn tfn (Test function)
+            sn macro_rules
+        "#]],
+    )
+}
+
+#[test]
+fn in_qualified_path() {
+    check(
+        r#"crate::$0"#,
+        expect![[r##"
+            kw pub(crate)
+            kw pub
+            kw unsafe
+            kw fn
+            kw const
+            kw type
+            kw impl
+            kw extern
+            kw use
+            kw trait
+            kw static
+            kw mod
+            kw enum
+            kw struct
+            kw union
+            md bar
+            ma foo!(…)    #[macro_export] macro_rules! foo
+        "##]],
+    )
+}
+
+#[test]
+fn after_unsafe_token() {
+    check(
+        r#"unsafe $0"#,
+        expect![[r#"
+            kw fn
+            kw trait
+            kw impl
+        "#]],
+    );
+}
+
+#[test]
+fn after_visibility() {
+    check(
+        r#"pub $0"#,
+        expect![[r#"
+            kw unsafe
+            kw fn
+            kw const
+            kw type
+            kw use
+            kw trait
+            kw static
+            kw mod
+            kw enum
+            kw struct
+            kw union
+        "#]],
+    );
+}
+
+#[test]
+fn after_visibility_unsafe() {
+    // FIXME this shouldn't show `impl`
+    check(
+        r#"pub unsafe $0"#,
+        expect![[r#"
+            kw fn
+            kw trait
+            kw impl
+        "#]],
+    );
+}
+
+#[test]
+fn in_impl_assoc_item_list() {
+    check(
+        r#"impl Struct { $0 }"#,
+        expect![[r##"
+            kw pub(crate)
+            kw pub
+            kw unsafe
+            kw fn
+            kw const
+            kw type
+            md bar
+            ma foo!(…)    #[macro_export] macro_rules! foo
+            ma foo!(…)    #[macro_export] macro_rules! foo
+        "##]],
+    )
+}
+
+#[test]
+fn in_impl_assoc_item_list_after_attr() {
+    check(
+        r#"impl Struct { #[attr] $0 }"#,
+        expect![[r#"
+            kw pub(crate)
+            kw pub
+            kw unsafe
+            kw fn
+            kw const
+            kw type
+        "#]],
+    )
+}
+
+#[test]
+fn in_trait_assoc_item_list() {
+    check(
+        r"trait Foo { $0 }",
+        expect![[r##"
+            kw unsafe
+            kw fn
+            kw const
+            kw type
+            md bar
+            ma foo!(…) #[macro_export] macro_rules! foo
+            ma foo!(…) #[macro_export] macro_rules! foo
+        "##]],
+    );
+}
diff --git a/crates/ide_completion/src/tests/items.rs b/crates/ide_completion/src/tests/items.rs
new file mode 100644
index 000000000..b98baffd6
--- /dev/null
+++ b/crates/ide_completion/src/tests/items.rs
@@ -0,0 +1,95 @@
+//! Completions tests for item specifics overall.
+//!
+//! Except for use items which are tested in [super::use_tree] and mod declarations with are tested
+//! in [crate::completions::mod_].
+use expect_test::{expect, Expect};
+
+use crate::tests::completion_list;
+
+fn check(ra_fixture: &str, expect: Expect) {
+    let base = r#"#[rustc_builtin_macro]
+pub macro Clone {}
+enum Enum { Variant }
+struct Struct {}
+#[macro_export]
+macro_rules! foo {}
+mod bar {}
+const CONST: () = ();
+trait Trait {}
+"#;
+    let actual = completion_list(&format!("{}{}", base, ra_fixture));
+    expect.assert_eq(&actual)
+}
+
+#[test]
+fn target_type_or_trait_in_impl_block() {
+    check(
+        r#"
+impl Tra$0
+"#,
+        expect![[r##"
+            tt Trait
+            en Enum
+            st Struct
+            md bar
+            ma foo!(…) #[macro_export] macro_rules! foo
+            ma foo!(…) #[macro_export] macro_rules! foo
+            bt u32
+        "##]],
+    )
+}
+
+#[test]
+fn target_type_in_trait_impl_block() {
+    check(
+        r#"
+impl Trait for Str$0
+"#,
+        expect![[r##"
+            tt Trait
+            en Enum
+            st Struct
+            md bar
+            ma foo!(…) #[macro_export] macro_rules! foo
+            ma foo!(…) #[macro_export] macro_rules! foo
+            bt u32
+        "##]],
+    )
+}
+
+#[test]
+fn after_trait_name_in_trait_def() {
+    check(
+        r"trait A $0",
+        expect![[r#"
+            kw where
+        "#]],
+    );
+}
+
+#[test]
+fn after_trait_or_target_name_in_impl() {
+    check(
+        r"impl Trait $0",
+        expect![[r#"
+            kw where
+            kw for
+        "#]],
+    );
+}
+
+#[test]
+fn before_record_field() {
+    check(
+        r#"
+struct Foo {
+    $0
+    pub f: i32,
+}
+"#,
+        expect![[r#"
+            kw pub(crate)
+            kw pub
+        "#]],
+    )
+}
diff --git a/crates/ide_completion/src/tests/pattern.rs b/crates/ide_completion/src/tests/pattern.rs
new file mode 100644
index 000000000..1ad5ccd97
--- /dev/null
+++ b/crates/ide_completion/src/tests/pattern.rs
@@ -0,0 +1,348 @@
+//! Completions tests for pattern position.
+use expect_test::{expect, Expect};
+
+use crate::tests::completion_list;
+
+fn check(ra_fixture: &str, expect: Expect) {
+    let actual = completion_list(ra_fixture);
+    expect.assert_eq(&actual)
+}
+
+fn check_with(ra_fixture: &str, expect: Expect) {
+    let base = r#"
+enum Enum { TupleV(u32), RecordV { field: u32 }, UnitV }
+use self::Enum::TupleV;
+mod module {}
+
+static STATIC: Unit = Unit;
+const CONST: Unit = Unit;
+struct Record { field: u32 }
+struct Tuple(u32);
+struct Unit
+macro_rules! makro {}
+"#;
+    let actual = completion_list(&format!("{}\n{}", base, ra_fixture));
+    expect.assert_eq(&actual)
+}
+
+#[test]
+fn ident_rebind_pat() {
+    check(
+        r#"
+fn quux() {
+    let en$0 @ x
+}
+"#,
+        expect![[r#"
+            kw mut
+        "#]],
+    );
+}
+
+#[test]
+fn ident_ref_pat() {
+    check(
+        r#"
+fn quux() {
+    let ref en$0
+}
+"#,
+        expect![[r#"
+            kw mut
+        "#]],
+    );
+    check(
+        r#"
+fn quux() {
+    let ref en$0 @ x
+}
+"#,
+        expect![[r#"
+            kw mut
+        "#]],
+    );
+}
+
+#[test]
+fn ident_ref_mut_pat() {
+    // FIXME mut is already here, don't complete it again
+    check(
+        r#"
+fn quux() {
+    let ref mut en$0
+}
+"#,
+        expect![[r#"
+            kw mut
+        "#]],
+    );
+    check(
+        r#"
+fn quux() {
+    let ref mut en$0 @ x
+}
+"#,
+        expect![[r#"
+            kw mut
+        "#]],
+    );
+}
+
+#[test]
+fn ref_pat() {
+    check(
+        r#"
+fn quux() {
+    let &en$0
+}
+"#,
+        expect![[r#"
+            kw mut
+        "#]],
+    );
+    // FIXME mut is already here, don't complete it again
+    check(
+        r#"
+fn quux() {
+    let &mut en$0
+}
+"#,
+        expect![[r#"
+            kw mut
+        "#]],
+    );
+}
+
+#[test]
+fn refutable() {
+    check_with(
+        r#"
+fn foo() {
+    if let a$0
+}
+"#,
+        expect![[r#"
+            kw mut
+            bn Record    Record { field$1 }$0
+            st Record
+            en Enum
+            bn Tuple     Tuple($1)$0
+            st Tuple
+            md module
+            bn TupleV    TupleV($1)$0
+            ev TupleV
+            st Unit
+            ct CONST
+            ma makro!(…) macro_rules! makro
+        "#]],
+    );
+}
+
+#[test]
+fn irrefutable() {
+    check_with(
+        r#"
+fn foo() {
+   let a$0
+}
+"#,
+        expect![[r#"
+            kw mut
+            bn Record    Record { field$1 }$0
+            st Record
+            bn Tuple     Tuple($1)$0
+            st Tuple
+            st Unit
+            ma makro!(…) macro_rules! makro
+        "#]],
+    );
+}
+
+#[test]
+fn in_param() {
+    check_with(
+        r#"
+fn foo(a$0) {
+}
+"#,
+        expect![[r#"
+            kw mut
+            bn Record    Record { field$1 }: Record$0
+            st Record
+            bn Tuple     Tuple($1): Tuple$0
+            st Tuple
+            st Unit
+            ma makro!(…) macro_rules! makro
+        "#]],
+    );
+}
+
+#[test]
+fn only_fn_like_macros() {
+    check(
+        r#"
+macro_rules! m { ($e:expr) => { $e } }
+
+#[rustc_builtin_macro]
+macro Clone {}
+
+fn foo() {
+    let x$0
+}
+"#,
+        expect![[r#"
+            kw mut
+            ma m!(…) macro_rules! m
+        "#]],
+    );
+}
+
+#[test]
+fn in_simple_macro_call() {
+    check(
+        r#"
+macro_rules! m { ($e:expr) => { $e } }
+enum E { X }
+
+fn foo() {
+   m!(match E::X { a$0 })
+}
+"#,
+        expect![[r#"
+            kw mut
+            ev E::X  ()
+            en E
+            ma m!(…) macro_rules! m
+        "#]],
+    );
+}
+
+#[test]
+fn omits_private_fields_pat() {
+    check(
+        r#"
+mod foo {
+    pub struct Record { pub field: i32, _field: i32 }
+    pub struct Tuple(pub u32, u32);
+    pub struct Invisible(u32, u32);
+}
+use foo::*;
+
+fn outer() {
+    if let a$0
+}
+"#,
+        expect![[r#"
+            kw mut
+            bn Record    Record { field$1, .. }$0
+            st Record
+            bn Tuple     Tuple($1, ..)$0
+            st Tuple
+            st Invisible
+            md foo
+        "#]],
+    )
+}
+
+// #[test]
+// fn only_shows_ident_completion() {
+//     check_edit(
+//         "Foo",
+//         r#"
+// struct Foo(i32);
+// fn main() {
+//     match Foo(92) {
+//         a$0(92) => (),
+//     }
+// }
+// "#,
+//         r#"
+// struct Foo(i32);
+// fn main() {
+//     match Foo(92) {
+//         Foo(92) => (),
+//     }
+// }
+// "#,
+//     );
+// }
+
+#[test]
+fn completes_self_pats() {
+    check(
+        r#"
+struct Foo(i32);
+impl Foo {
+    fn foo() {
+        match Foo(0) {
+            a$0
+        }
+    }
+}
+    "#,
+        expect![[r#"
+            kw mut
+            bn Self Self($1)$0
+            sp Self
+            bn Foo  Foo($1)$0
+            st Foo
+        "#]],
+    )
+}
+
+#[test]
+fn completes_qualified_variant() {
+    check(
+        r#"
+enum Foo {
+    Bar { baz: i32 }
+}
+impl Foo {
+    fn foo() {
+        match {Foo::Bar { baz: 0 }} {
+            B$0
+        }
+    }
+}
+    "#,
+        expect![[r#"
+            kw mut
+            bn Self::Bar Self::Bar { baz$1 }$0
+            ev Self::Bar { baz: i32 }
+            bn Foo::Bar  Foo::Bar { baz$1 }$0
+            ev Foo::Bar  { baz: i32 }
+            sp Self
+            en Foo
+        "#]],
+    )
+}
+
+#[test]
+fn completes_in_record_field_pat() {
+    check(
+        r#"
+struct Foo { bar: Bar }
+struct Bar(u32);
+fn outer(Foo { bar: $0 }: Foo) {}
+"#,
+        expect![[r#"
+            kw mut
+            bn Foo Foo { bar$1 }$0
+            st Foo
+            bn Bar Bar($1)$0
+            st Bar
+        "#]],
+    )
+}
+
+#[test]
+fn skips_in_record_field_pat_name() {
+    check(
+        r#"
+struct Foo { bar: Bar }
+struct Bar(u32);
+fn outer(Foo { bar$0 }: Foo) {}
+"#,
+        expect![[r#""#]],
+    )
+}
diff --git a/crates/ide_completion/src/tests/type_pos.rs b/crates/ide_completion/src/tests/type_pos.rs
new file mode 100644
index 000000000..1ab47b27e
--- /dev/null
+++ b/crates/ide_completion/src/tests/type_pos.rs
@@ -0,0 +1,177 @@
+//! Completions tests for type position.
+use expect_test::{expect, Expect};
+
+use crate::tests::completion_list;
+
+fn check_with(ra_fixture: &str, expect: Expect) {
+    let base = r#"
+enum Enum { TupleV(u32), RecordV { field: u32 }, UnitV }
+use self::Enum::TupleV;
+mod module {}
+
+trait Trait {}
+static STATIC: Unit = Unit;
+const CONST: Unit = Unit;
+struct Record { field: u32 }
+struct Tuple(u32);
+struct Unit
+macro_rules! makro {}
+"#;
+    let actual = completion_list(&format!("{}\n{}", base, ra_fixture));
+    expect.assert_eq(&actual)
+}
+
+#[test]
+fn record_field_ty() {
+    check_with(
+        r#"
+struct Foo<'lt, T, const C: usize> {
+    f: $0
+}
+"#,
+        expect![[r#"
+            sp Self
+            tp T
+            tt Trait
+            en Enum
+            st Record
+            st Tuple
+            md module
+            st Foo<…>
+            st Unit
+            ma makro!(…) macro_rules! makro
+            bt u32
+        "#]],
+    )
+}
+
+#[test]
+fn tuple_struct_field() {
+    check_with(
+        r#"
+struct Foo<'lt, T, const C: usize>(f$0);
+"#,
+        expect![[r#"
+            kw pub(crate)
+            kw pub
+            sp Self
+            tp T
+            tt Trait
+            en Enum
+            st Record
+            st Tuple
+            md module
+            st Foo<…>
+            st Unit
+            ma makro!(…)  macro_rules! makro
+            bt u32
+        "#]],
+    )
+}
+
+#[test]
+fn fn_return_type() {
+    check_with(
+        r#"
+fn x<'lt, T, const C: usize>() -> $0
+"#,
+        expect![[r#"
+            tp T
+            tt Trait
+            en Enum
+            st Record
+            st Tuple
+            md module
+            st Unit
+            ma makro!(…) macro_rules! makro
+            bt u32
+        "#]],
+    );
+}
+
+#[test]
+fn body_type_pos() {
+    check_with(
+        r#"
+fn foo<'lt, T, const C: usize>() {
+    let local = ();
+    let _: $0;
+}
+"#,
+        expect![[r#"
+            tp T
+            tt Trait
+            en Enum
+            st Record
+            st Tuple
+            md module
+            st Unit
+            ma makro!(…) macro_rules! makro
+            bt u32
+        "#]],
+    );
+    check_with(
+        r#"
+fn foo<'lt, T, const C: usize>() {
+    let local = ();
+    let _: self::$0;
+}
+"#,
+        expect![[r#"
+            tt Trait
+            en Enum
+            st Record
+            st Tuple
+            md module
+            st Unit
+        "#]],
+    );
+}
+
+#[test]
+fn completes_types_and_const_in_arg_list() {
+    // FIXME: we should complete the lifetime here for now
+    check_with(
+        r#"
+trait Trait2 {
+    type Foo;
+}
+
+fn foo<'lt, T: Trait2<$0>, const CONST_PARAM: usize>(_: T) {}
+"#,
+        expect![[r#"
+            ta Foo =       type Foo;
+            tp T
+            cp CONST_PARAM
+            tt Trait
+            en Enum
+            st Record
+            st Tuple
+            tt Trait2
+            md module
+            st Unit
+            ct CONST
+            ma makro!(…)   macro_rules! makro
+            bt u32
+        "#]],
+    );
+    check_with(
+        r#"
+trait Trait2 {
+    type Foo;
+}
+
+fn foo<'lt, T: Trait2<self::$0>, const CONST_PARAM: usize>(_: T) {}
+    "#,
+        expect![[r#"
+            tt Trait
+            en Enum
+            st Record
+            st Tuple
+            tt Trait2
+            md module
+            st Unit
+            ct CONST
+        "#]],
+    );
+}
diff --git a/crates/ide_completion/src/tests/use_tree.rs b/crates/ide_completion/src/tests/use_tree.rs
new file mode 100644
index 000000000..7e6748ccc
--- /dev/null
+++ b/crates/ide_completion/src/tests/use_tree.rs
@@ -0,0 +1,255 @@
+use expect_test::{expect, Expect};
+
+use crate::tests::completion_list;
+
+fn check(ra_fixture: &str, expect: Expect) {
+    let actual = completion_list(ra_fixture);
+    expect.assert_eq(&actual)
+}
+
+#[test]
+fn use_tree_start() {
+    cov_mark::check!(only_completes_modules_in_import);
+    check(
+        r#"
+//- /lib.rs crate:main deps:other_crate
+use f$0
+
+struct Foo;
+mod foo {}
+//- /other_crate/lib.rs crate:other_crate
+// nothing here
+"#,
+        expect![[r#"
+            kw crate::
+            kw self::
+            kw super::
+            md foo
+            md other_crate
+        "#]],
+    );
+}
+
+#[test]
+fn dont_complete_current_use() {
+    cov_mark::check!(dont_complete_current_use);
+    check(r#"use self::foo$0;"#, expect![[r#""#]]);
+    check(
+        r#"
+mod foo { pub struct S; }
+use self::{foo::*, bar$0};
+"#,
+        expect![[r#"
+            kw self
+            st S
+            md foo
+        "#]],
+    );
+}
+
+#[test]
+fn nested_use_tree() {
+    check(
+        r#"
+mod foo {
+    pub mod bar {
+        pub struct FooBar;
+    }
+}
+use foo::{bar::$0}
+"#,
+        expect![[r#"
+            st FooBar
+        "#]],
+    );
+    check(
+        r#"
+mod foo {
+    pub mod bar {
+        pub struct FooBar;
+    }
+}
+use foo::{$0}
+"#,
+        expect![[r#"
+            kw self
+            md bar
+        "#]],
+    );
+}
+
+#[test]
+fn deeply_nested_use_tree() {
+    check(
+        r#"
+mod foo {
+    pub mod bar {
+        pub mod baz {
+            pub struct FooBarBaz;
+        }
+    }
+}
+use foo::{bar::{baz::$0}}
+"#,
+        expect![[r#"
+            st FooBarBaz
+        "#]],
+    );
+    check(
+        r#"
+mod foo {
+    pub mod bar {
+        pub mod baz {
+            pub struct FooBarBaz;
+        }
+    }
+}
+use foo::{bar::{$0}}
+"#,
+        expect![[r#"
+            kw self
+            md baz
+        "#]],
+    );
+}
+
+#[test]
+fn plain_qualified_use_tree() {
+    check(
+        r#"
+use foo::$0
+
+mod foo {
+    struct Private;
+    pub struct Foo;
+}
+struct Bar;
+"#,
+        expect![[r#"
+            st Foo
+        "#]],
+    );
+}
+
+#[test]
+fn self_qualified_use_tree() {
+    check(
+        r#"
+use self::$0
+
+mod foo {}
+struct Bar;
+"#,
+        expect![[r#"
+            md foo
+            st Bar
+        "#]],
+    );
+}
+
+#[test]
+fn super_qualified_use_tree() {
+    check(
+        r#"
+mod bar {
+    use super::$0
+}
+
+mod foo {}
+struct Bar;
+"#,
+        expect![[r#"
+            kw super::
+            st Bar
+            md bar
+            md foo
+        "#]],
+    );
+}
+
+#[test]
+fn super_super_qualified_use_tree() {
+    check(
+        r#"
+mod a {
+    const A: usize = 0;
+    mod b {
+        const B: usize = 0;
+        mod c { use super::super::$0 }
+    }
+}
+"#,
+        expect![[r#"
+            kw super::
+            md b
+            ct A
+        "#]],
+    );
+}
+
+#[test]
+fn crate_qualified_use_tree() {
+    check(
+        r#"
+use crate::$0
+
+mod foo {}
+struct Bar;
+"#,
+        expect![[r#"
+            md foo
+            st Bar
+        "#]],
+    );
+}
+
+#[test]
+fn extern_crate_qualified_use_tree() {
+    check(
+        r#"
+//- /lib.rs crate:main deps:other_crate
+use other_crate::$0
+//- /other_crate/lib.rs crate:other_crate
+pub struct Foo;
+pub mod foo {}
+"#,
+        expect![[r#"
+            st Foo
+            md foo
+        "#]],
+    );
+}
+
+#[test]
+fn pub_use_tree() {
+    check(
+        r#"
+pub struct X;
+pub mod bar {}
+pub use $0;
+"#,
+        expect![[r#"
+            kw crate::
+            kw self::
+            kw super::
+            md bar
+        "#]],
+    );
+}
+
+#[test]
+fn use_tree_braces_at_start() {
+    check(
+        r#"
+struct X;
+mod bar {}
+use {$0};
+"#,
+        expect![[r#"
+            kw crate::
+            kw self::
+            kw super::
+            md bar
+        "#]],
+    );
+}
diff --git a/crates/ide_db/src/assists.rs b/crates/ide_db/src/assists.rs
new file mode 100644
index 000000000..7881d8369
--- /dev/null
+++ b/crates/ide_db/src/assists.rs
@@ -0,0 +1,136 @@
+//! This module defines the `Assist` data structure. The actual assist live in
+//! the `ide_assists` downstream crate. We want to define the data structures in
+//! this low-level crate though, because `ide_diagnostics` also need them
+//! (fixits for diagnostics and assists are the same thing under the hood). We
+//! want to compile `ide_assists` and `ide_diagnostics` in parallel though, so
+//! we pull the common definitions upstream, to this crate.
+
+use std::str::FromStr;
+
+use syntax::TextRange;
+
+use crate::{label::Label, source_change::SourceChange};
+
+#[derive(Debug, Clone)]
+pub struct Assist {
+    pub id: AssistId,
+    /// Short description of the assist, as shown in the UI.
+    pub label: Label,
+    pub group: Option<GroupLabel>,
+    /// Target ranges are used to sort assists: the smaller the target range,
+    /// the more specific assist is, and so it should be sorted first.
+    pub target: TextRange,
+    /// Computing source change sometimes is much more costly then computing the
+    /// other fields. Additionally, the actual change is not required to show
+    /// the lightbulb UI, it only is needed when the user tries to apply an
+    /// assist. So, we compute it lazily: the API allow requesting assists with
+    /// or without source change. We could (and in fact, used to) distinguish
+    /// between resolved and unresolved assists at the type level, but this is
+    /// cumbersome, especially if you want to embed an assist into another data
+    /// structure, such as a diagnostic.
+    pub source_change: Option<SourceChange>,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum AssistKind {
+    // FIXME: does the None variant make sense? Probably not.
+    None,
+
+    QuickFix,
+    Generate,
+    Refactor,
+    RefactorExtract,
+    RefactorInline,
+    RefactorRewrite,
+}
+
+impl AssistKind {
+    pub fn contains(self, other: AssistKind) -> bool {
+        if self == other {
+            return true;
+        }
+
+        match self {
+            AssistKind::None | AssistKind::Generate => true,
+            AssistKind::Refactor => match other {
+                AssistKind::RefactorExtract
+                | AssistKind::RefactorInline
+                | AssistKind::RefactorRewrite => true,
+                _ => false,
+            },
+            _ => false,
+        }
+    }
+
+    pub fn name(&self) -> &str {
+        match self {
+            AssistKind::None => "None",
+            AssistKind::QuickFix => "QuickFix",
+            AssistKind::Generate => "Generate",
+            AssistKind::Refactor => "Refactor",
+            AssistKind::RefactorExtract => "RefactorExtract",
+            AssistKind::RefactorInline => "RefactorInline",
+            AssistKind::RefactorRewrite => "RefactorRewrite",
+        }
+    }
+}
+
+impl FromStr for AssistKind {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "None" => Ok(AssistKind::None),
+            "QuickFix" => Ok(AssistKind::QuickFix),
+            "Generate" => Ok(AssistKind::Generate),
+            "Refactor" => Ok(AssistKind::Refactor),
+            "RefactorExtract" => Ok(AssistKind::RefactorExtract),
+            "RefactorInline" => Ok(AssistKind::RefactorInline),
+            "RefactorRewrite" => Ok(AssistKind::RefactorRewrite),
+            unknown => Err(format!("Unknown AssistKind: '{}'", unknown)),
+        }
+    }
+}
+
+/// Unique identifier of the assist, should not be shown to the user
+/// directly.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct AssistId(pub &'static str, pub AssistKind);
+
+/// A way to control how many asssist to resolve during the assist resolution.
+/// When an assist is resolved, its edits are calculated that might be costly to always do by default.
+#[derive(Debug)]
+pub enum AssistResolveStrategy {
+    /// No assists should be resolved.
+    None,
+    /// All assists should be resolved.
+    All,
+    /// Only a certain assist should be resolved.
+    Single(SingleResolve),
+}
+
+/// Hold the [`AssistId`] data of a certain assist to resolve.
+/// The original id object cannot be used due to a `'static` lifetime
+/// and the requirement to construct this struct dynamically during the resolve handling.
+#[derive(Debug)]
+pub struct SingleResolve {
+    /// The id of the assist.
+    pub assist_id: String,
+    // The kind of the assist.
+    pub assist_kind: AssistKind,
+}
+
+impl AssistResolveStrategy {
+    pub fn should_resolve(&self, id: &AssistId) -> bool {
+        match self {
+            AssistResolveStrategy::None => false,
+            AssistResolveStrategy::All => true,
+            AssistResolveStrategy::Single(single_resolve) => {
+                single_resolve.assist_id == id.0 && single_resolve.assist_kind == id.1
+            }
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct GroupLabel(pub String);
diff --git a/crates/ide_db/src/helpers.rs b/crates/ide_db/src/helpers.rs
index 00900cdc2..d96028cbc 100644
--- a/crates/ide_db/src/helpers.rs
+++ b/crates/ide_db/src/helpers.rs
@@ -74,12 +74,19 @@ pub fn visit_file_defs(
 /// somewhat similar to the known paths infra inside hir, but it different; We
 /// want to make sure that IDE specific paths don't become interesting inside
 /// the compiler itself as well.
+///
+/// Note that, by default, rust-analyzer tests **do not** include core or std
+/// libraries. If you are writing tests for functionality using [`FamousDefs`],
+/// you'd want to include [minicore](test_utils::MiniCore) declaration at the
+/// start of your tests:
+///
+/// ```
+/// //- minicore: iterator, ord, derive
+/// ```
 pub struct FamousDefs<'a, 'b>(pub &'a Semantics<'b, RootDatabase>, pub Option<Crate>);
 
 #[allow(non_snake_case)]
 impl FamousDefs<'_, '_> {
-    pub const FIXTURE: &'static str = include_str!("helpers/famous_defs_fixture.rs");
-
     pub fn std(&self) -> Option<Crate> {
         self.find_crate("std")
     }
diff --git a/crates/ide_db/src/helpers/famous_defs_fixture.rs b/crates/ide_db/src/helpers/famous_defs_fixture.rs
deleted file mode 100644
index 312851966..000000000
--- a/crates/ide_db/src/helpers/famous_defs_fixture.rs
+++ /dev/null
@@ -1,153 +0,0 @@
-//- /libcore.rs crate:core
-//! Signatures of traits, types and functions from the core lib for use in tests.
-pub mod cmp {
-
-    pub trait Ord {
-        fn cmp(&self, other: &Self) -> Ordering;
-        fn max(self, other: Self) -> Self;
-        fn min(self, other: Self) -> Self;
-        fn clamp(self, min: Self, max: Self) -> Self;
-    }
-}
-
-pub mod convert {
-    pub trait From<T> {
-        fn from(t: T) -> Self;
-    }
-
-    pub trait Into<T> {
-        pub fn into(self) -> T;
-    }
-}
-
-pub mod default {
-    pub trait Default {
-        fn default() -> Self;
-    }
-}
-
-pub mod iter {
-    pub use self::traits::{collect::IntoIterator, iterator::Iterator};
-    mod traits {
-        pub(crate) mod iterator {
-            use crate::option::Option;
-            pub trait Iterator {
-                type Item;
-                fn next(&mut self) -> Option<Self::Item>;
-                fn by_ref(&mut self) -> &mut Self {
-                    self
-                }
-                fn take(self, n: usize) -> crate::iter::Take<Self> {
-                    crate::iter::Take { inner: self }
-                }
-            }
-
-            impl<I: Iterator> Iterator for &mut I {
-                type Item = I::Item;
-                fn next(&mut self) -> Option<I::Item> {
-                    (**self).next()
-                }
-            }
-        }
-        pub(crate) mod collect {
-            pub trait IntoIterator {
-                type Item;
-            }
-        }
-    }
-
-    pub use self::sources::*;
-    pub(crate) mod sources {
-        use super::Iterator;
-        use crate::option::Option::{self, *};
-        pub struct Repeat<A> {
-            element: A,
-        }
-
-        pub fn repeat<T>(elt: T) -> Repeat<T> {
-            Repeat { element: elt }
-        }
-
-        impl<A> Iterator for Repeat<A> {
-            type Item = A;
-
-            fn next(&mut self) -> Option<A> {
-                None
-            }
-        }
-    }
-
-    pub use self::adapters::*;
-    pub(crate) mod adapters {
-        use super::Iterator;
-        use crate::option::Option::{self, *};
-        pub struct Take<I> {
-            pub(crate) inner: I,
-        }
-        impl<I> Iterator for Take<I>
-        where
-            I: Iterator,
-        {
-            type Item = <I as Iterator>::Item;
-            fn next(&mut self) -> Option<<I as Iterator>::Item> {
-                None
-            }
-        }
-    }
-}
-
-pub mod ops {
-    #[lang = "fn"]
-    pub trait Fn<Args>: FnMut<Args> {
-        extern "rust-call" fn call(&self, args: Args) -> Self::Output;
-    }
-
-    #[lang = "fn_mut"]
-    pub trait FnMut<Args>: FnOnce<Args> {
-        extern "rust-call" fn call_mut(&mut self, args: Args) -> Self::Output;
-    }
-    #[lang = "fn_once"]
-    pub trait FnOnce<Args> {
-        #[lang = "fn_once_output"]
-        type Output;
-        extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-    }
-
-    #[lang = "deref"]
-    pub trait Deref {
-        type Target: ?Sized;
-        fn deref(&self) -> &Self::Target;
-    }
-}
-
-pub mod option {
-    pub enum Option<T> {
-        None,
-        Some(T),
-    }
-}
-
-pub mod prelude {
-    pub mod rust_2018 {
-        pub use crate::{
-            cmp::Ord,
-            convert::{From, Into},
-            default::Default,
-            iter::{IntoIterator, Iterator},
-            ops::{Fn, FnMut, FnOnce},
-            option::Option::{self, *},
-        };
-    }
-}
-#[prelude_import]
-pub use prelude::rust_2018::*;
-//- /libstd.rs crate:std deps:core
-//! Signatures of traits, types and functions from the std lib for use in tests.
-
-/// Docs for return_keyword
-mod return_keyword {}
-
-/// Docs for prim_str
-mod prim_str {}
-
-pub use core::ops;
diff --git a/crates/ide_db/src/helpers/insert_use.rs b/crates/ide_db/src/helpers/insert_use.rs
index 10bbafe77..e6b4832e7 100644
--- a/crates/ide_db/src/helpers/insert_use.rs
+++ b/crates/ide_db/src/helpers/insert_use.rs
@@ -5,7 +5,7 @@ use hir::Semantics;
 use syntax::{
     algo,
     ast::{self, make, AstNode, AttrsOwner, ModuleItemOwner, PathSegmentKind, VisibilityOwner},
-    ted, AstToken, Direction, NodeOrToken, SyntaxNode, SyntaxToken,
+    match_ast, ted, AstToken, Direction, NodeOrToken, SyntaxNode, SyntaxToken,
 };
 
 use crate::{
@@ -36,22 +36,39 @@ pub struct InsertUseConfig {
     pub enforce_granularity: bool,
     pub prefix_kind: PrefixKind,
     pub group: bool,
+    pub skip_glob_imports: bool,
 }
 
 #[derive(Debug, Clone)]
 pub enum ImportScope {
     File(ast::SourceFile),
     Module(ast::ItemList),
+    Block(ast::BlockExpr),
 }
 
 impl ImportScope {
-    pub fn from(syntax: SyntaxNode) -> Option<Self> {
-        if let Some(module) = ast::Module::cast(syntax.clone()) {
-            module.item_list().map(ImportScope::Module)
-        } else if let this @ Some(_) = ast::SourceFile::cast(syntax.clone()) {
-            this.map(ImportScope::File)
-        } else {
-            ast::ItemList::cast(syntax).map(ImportScope::Module)
+    fn from(syntax: SyntaxNode) -> Option<Self> {
+        fn contains_cfg_attr(attrs: &dyn AttrsOwner) -> bool {
+            attrs
+                .attrs()
+                .any(|attr| attr.as_simple_call().map_or(false, |(ident, _)| ident == "cfg"))
+        }
+        match_ast! {
+            match syntax {
+                ast::Module(module) => module.item_list().map(ImportScope::Module),
+                ast::SourceFile(file) => Some(ImportScope::File(file)),
+                ast::Fn(func) => contains_cfg_attr(&func).then(|| func.body().map(ImportScope::Block)).flatten(),
+                ast::Const(konst) => contains_cfg_attr(&konst).then(|| match konst.body()? {
+                    ast::Expr::BlockExpr(block) => Some(block),
+                    _ => None,
+                }).flatten().map(ImportScope::Block),
+                ast::Static(statik) => contains_cfg_attr(&statik).then(|| match statik.body()? {
+                    ast::Expr::BlockExpr(block) => Some(block),
+                    _ => None,
+                }).flatten().map(ImportScope::Block),
+                _ => None,
+
+            }
         }
     }
 
@@ -72,6 +89,7 @@ impl ImportScope {
         match self {
             ImportScope::File(file) => file.syntax(),
             ImportScope::Module(item_list) => item_list.syntax(),
+            ImportScope::Block(block) => block.syntax(),
         }
     }
 
@@ -79,6 +97,7 @@ impl ImportScope {
         match self {
             ImportScope::File(file) => ImportScope::File(file.clone_for_update()),
             ImportScope::Module(item_list) => ImportScope::Module(item_list.clone_for_update()),
+            ImportScope::Block(block) => ImportScope::Block(block.clone_for_update()),
         }
     }
 
@@ -95,6 +114,7 @@ impl ImportScope {
         let mut use_stmts = match self {
             ImportScope::File(f) => f.items(),
             ImportScope::Module(m) => m.items(),
+            ImportScope::Block(b) => b.items(),
         }
         .filter_map(use_stmt);
         let mut res = ImportGranularityGuess::Unknown;
@@ -153,7 +173,7 @@ enum ImportGranularityGuess {
 }
 
 /// Insert an import path into the given file/node. A `merge` value of none indicates that no import merging is allowed to occur.
-pub fn insert_use<'a>(scope: &ImportScope, path: ast::Path, cfg: InsertUseConfig) {
+pub fn insert_use<'a>(scope: &ImportScope, path: ast::Path, cfg: &InsertUseConfig) {
     let _p = profile::span("insert_use");
     let mut mb = match cfg.granularity {
         ImportGranularity::Crate => Some(MergeBehavior::Crate),
@@ -175,7 +195,10 @@ pub fn insert_use<'a>(scope: &ImportScope, path: ast::Path, cfg: InsertUseConfig
         make::use_(None, make::use_tree(path.clone(), None, None, false)).clone_for_update();
     // merge into existing imports if possible
     if let Some(mb) = mb {
-        for existing_use in scope.as_syntax_node().children().filter_map(ast::Use::cast) {
+        let filter = |it: &_| !(cfg.skip_glob_imports && ast::Use::is_simple_glob(it));
+        for existing_use in
+            scope.as_syntax_node().children().filter_map(ast::Use::cast).filter(filter)
+        {
             if let Some(merged) = try_merge_imports(&existing_use, &use_item, mb) {
                 ted::replace(existing_use.syntax(), merged.syntax());
                 return;
@@ -315,28 +338,29 @@ fn insert_use_(
         ted::insert(ted::Position::after(last_inner_element), make::tokens::single_newline());
         return;
     }
-    match scope {
+    let l_curly = match scope {
         ImportScope::File(_) => {
             cov_mark::hit!(insert_group_empty_file);
             ted::insert(ted::Position::first_child_of(scope_syntax), make::tokens::blank_line());
-            ted::insert(ted::Position::first_child_of(scope_syntax), use_item.syntax())
+            ted::insert(ted::Position::first_child_of(scope_syntax), use_item.syntax());
+            return;
         }
+        // don't insert the imports before the item list/block expr's opening curly brace
+        ImportScope::Module(item_list) => item_list.l_curly_token(),
         // don't insert the imports before the item list's opening curly brace
-        ImportScope::Module(item_list) => match item_list.l_curly_token() {
-            Some(b) => {
-                cov_mark::hit!(insert_group_empty_module);
-                ted::insert(ted::Position::after(&b), make::tokens::single_newline());
-                ted::insert(ted::Position::after(&b), use_item.syntax());
-            }
-            None => {
-                // This should never happens, broken module syntax node
-                ted::insert(
-                    ted::Position::first_child_of(scope_syntax),
-                    make::tokens::blank_line(),
-                );
-                ted::insert(ted::Position::first_child_of(scope_syntax), use_item.syntax());
-            }
-        },
+        ImportScope::Block(block) => block.l_curly_token(),
+    };
+    match l_curly {
+        Some(b) => {
+            cov_mark::hit!(insert_group_empty_module);
+            ted::insert(ted::Position::after(&b), make::tokens::single_newline());
+            ted::insert(ted::Position::after(&b), use_item.syntax());
+        }
+        None => {
+            // This should never happens, broken module syntax node
+            ted::insert(ted::Position::first_child_of(scope_syntax), make::tokens::blank_line());
+            ted::insert(ted::Position::first_child_of(scope_syntax), use_item.syntax());
+        }
     }
 }
 
diff --git a/crates/ide_db/src/helpers/insert_use/tests.rs b/crates/ide_db/src/helpers/insert_use/tests.rs
index 70b11bf81..01894630a 100644
--- a/crates/ide_db/src/helpers/insert_use/tests.rs
+++ b/crates/ide_db/src/helpers/insert_use/tests.rs
@@ -1,12 +1,63 @@
 use super::*;
 
 use hir::PrefixKind;
-use test_utils::assert_eq_text;
+use test_utils::{assert_eq_text, extract_range_or_offset, CURSOR_MARKER};
+
+#[test]
+fn respects_cfg_attr_fn() {
+    check(
+        r"bar::Bar",
+        r#"
+#[cfg(test)]
+fn foo() {$0}
+"#,
+        r#"
+#[cfg(test)]
+fn foo() {
+use bar::Bar;
+}
+"#,
+        ImportGranularity::Crate,
+    );
+}
+
+#[test]
+fn respects_cfg_attr_const() {
+    check(
+        r"bar::Bar",
+        r#"
+#[cfg(test)]
+const FOO: Bar = {$0};
+"#,
+        r#"
+#[cfg(test)]
+const FOO: Bar = {
+use bar::Bar;
+};
+"#,
+        ImportGranularity::Crate,
+    );
+}
+
+#[test]
+fn insert_skips_lone_glob_imports() {
+    check(
+        "use foo::baz::A",
+        r"
+use foo::bar::*;
+",
+        r"
+use foo::bar::*;
+use foo::baz::A;
+",
+        ImportGranularity::Crate,
+    );
+}
 
 #[test]
 fn insert_not_group() {
     cov_mark::check!(insert_no_grouping_last);
-    check(
+    check_with_config(
         "use external_crate2::bar::A",
         r"
 use std::bar::B;
@@ -21,24 +72,32 @@ use crate::bar::A;
 use self::bar::A;
 use super::bar::A;
 use external_crate2::bar::A;",
-        ImportGranularity::Item,
-        false,
-        false,
+        &InsertUseConfig {
+            granularity: ImportGranularity::Item,
+            enforce_granularity: true,
+            prefix_kind: PrefixKind::Plain,
+            group: false,
+            skip_glob_imports: true,
+        },
     );
 }
 
 #[test]
 fn insert_not_group_empty() {
     cov_mark::check!(insert_no_grouping_last2);
-    check(
+    check_with_config(
         "use external_crate2::bar::A",
         r"",
         r"use external_crate2::bar::A;
 
 ",
-        ImportGranularity::Item,
-        false,
-        false,
+        &InsertUseConfig {
+            granularity: ImportGranularity::Item,
+            enforce_granularity: true,
+            prefix_kind: PrefixKind::Plain,
+            group: false,
+            skip_glob_imports: true,
+        },
     );
 }
 
@@ -277,13 +336,15 @@ fn insert_empty_module() {
     cov_mark::check!(insert_group_empty_module);
     check(
         "foo::bar",
-        "mod x {}",
-        r"{
+        r"
+mod x {$0}
+",
+        r"
+mod x {
     use foo::bar;
-}",
+}
+",
         ImportGranularity::Item,
-        true,
-        true,
     )
 }
 
@@ -511,13 +572,14 @@ use std::io;
 }
 
 #[test]
-#[ignore] // FIXME: Support this
 fn split_out_merge() {
+    // FIXME: This is suboptimal, we want to get `use std::fmt::{self, Result}`
+    // instead.
     check_module(
         "std::fmt::Result",
         r"use std::{fmt, io};",
-        r"use std::fmt::{self, Result};
-use std::io;",
+        r"use std::fmt::Result;
+use std::{fmt, io};",
     )
 }
 
@@ -533,17 +595,35 @@ fn merge_groups_self() {
 
 #[test]
 fn merge_mod_into_glob() {
-    check_crate(
+    check_with_config(
         "token::TokenKind",
         r"use token::TokenKind::*;",
         r"use token::TokenKind::{*, self};",
+        &InsertUseConfig {
+            granularity: ImportGranularity::Crate,
+            enforce_granularity: true,
+            prefix_kind: PrefixKind::Plain,
+            group: false,
+            skip_glob_imports: false,
+        },
     )
     // FIXME: have it emit `use token::TokenKind::{self, *}`?
 }
 
 #[test]
 fn merge_self_glob() {
-    check_crate("self", r"use self::*;", r"use self::{*, self};")
+    check_with_config(
+        "self",
+        r"use self::*;",
+        r"use self::{*, self};",
+        &InsertUseConfig {
+            granularity: ImportGranularity::Crate,
+            enforce_granularity: true,
+            prefix_kind: PrefixKind::Plain,
+            group: false,
+            skip_glob_imports: false,
+        },
+    )
     // FIXME: have it emit `use {self, *}`?
 }
 
@@ -756,19 +836,24 @@ use foo::bar::qux;
     );
 }
 
-fn check(
+fn check_with_config(
     path: &str,
     ra_fixture_before: &str,
     ra_fixture_after: &str,
-    granularity: ImportGranularity,
-    module: bool,
-    group: bool,
+    config: &InsertUseConfig,
 ) {
-    let mut syntax = ast::SourceFile::parse(ra_fixture_before).tree().syntax().clone();
-    if module {
-        syntax = syntax.descendants().find_map(ast::Module::cast).unwrap().syntax().clone();
-    }
-    let file = super::ImportScope::from(syntax.clone_for_update()).unwrap();
+    let (text, pos) = if ra_fixture_before.contains(CURSOR_MARKER) {
+        let (range_or_offset, text) = extract_range_or_offset(ra_fixture_before);
+        (text, Some(range_or_offset))
+    } else {
+        (ra_fixture_before.to_owned(), None)
+    };
+    let syntax = ast::SourceFile::parse(&text).tree().syntax().clone_for_update();
+    let file = pos
+        .and_then(|pos| syntax.token_at_offset(pos.expect_offset()).next()?.parent())
+        .and_then(|it| super::ImportScope::find_insert_use_container(&it))
+        .or_else(|| super::ImportScope::from(syntax))
+        .unwrap();
     let path = ast::SourceFile::parse(&format!("use {};", path))
         .tree()
         .syntax()
@@ -776,30 +861,41 @@ fn check(
         .find_map(ast::Path::cast)
         .unwrap();
 
-    insert_use(
-        &file,
+    insert_use(&file, path, config);
+    let result = file.as_syntax_node().ancestors().last().unwrap().to_string();
+    assert_eq_text!(ra_fixture_after, &result);
+}
+
+fn check(
+    path: &str,
+    ra_fixture_before: &str,
+    ra_fixture_after: &str,
+    granularity: ImportGranularity,
+) {
+    check_with_config(
         path,
-        InsertUseConfig {
+        ra_fixture_before,
+        ra_fixture_after,
+        &InsertUseConfig {
             granularity,
             enforce_granularity: true,
             prefix_kind: PrefixKind::Plain,
-            group,
+            group: true,
+            skip_glob_imports: true,
         },
-    );
-    let result = file.as_syntax_node().to_string();
-    assert_eq_text!(ra_fixture_after, &result);
+    )
 }
 
 fn check_crate(path: &str, ra_fixture_before: &str, ra_fixture_after: &str) {
-    check(path, ra_fixture_before, ra_fixture_after, ImportGranularity::Crate, false, true)
+    check(path, ra_fixture_before, ra_fixture_after, ImportGranularity::Crate)
 }
 
 fn check_module(path: &str, ra_fixture_before: &str, ra_fixture_after: &str) {
-    check(path, ra_fixture_before, ra_fixture_after, ImportGranularity::Module, false, true)
+    check(path, ra_fixture_before, ra_fixture_after, ImportGranularity::Module)
 }
 
 fn check_none(path: &str, ra_fixture_before: &str, ra_fixture_after: &str) {
-    check(path, ra_fixture_before, ra_fixture_after, ImportGranularity::Item, false, true)
+    check(path, ra_fixture_before, ra_fixture_after, ImportGranularity::Item)
 }
 
 fn check_merge_only_fail(ra_fixture0: &str, ra_fixture1: &str, mb: MergeBehavior) {
diff --git a/crates/ide_db/src/lib.rs b/crates/ide_db/src/lib.rs
index 105607dca..bde8767dd 100644
--- a/crates/ide_db/src/lib.rs
+++ b/crates/ide_db/src/lib.rs
@@ -3,17 +3,21 @@
 //! It is mainly a `HirDatabase` for semantic analysis, plus a `SymbolsDatabase`, for fuzzy search.
 
 mod apply_change;
+pub mod assists;
 pub mod label;
 pub mod line_index;
 pub mod symbol_index;
 pub mod defs;
-pub mod search;
 pub mod items_locator;
 pub mod source_change;
 pub mod ty_filter;
 pub mod traits;
 pub mod call_info;
 pub mod helpers;
+pub mod path_transform;
+
+pub mod search;
+pub mod rename;
 
 use std::{fmt, sync::Arc};
 
diff --git a/crates/ide_assists/src/path_transform.rs b/crates/ide_db/src/path_transform.rs
index 48a7fa06a..f3d7aa920 100644
--- a/crates/ide_assists/src/path_transform.rs
+++ b/crates/ide_db/src/path_transform.rs
@@ -1,7 +1,7 @@
 //! See [`PathTransform`].
 
+use crate::helpers::mod_path_to_ast;
 use hir::{HirDisplay, SemanticsScope};
-use ide_db::helpers::mod_path_to_ast;
 use rustc_hash::FxHashMap;
 use syntax::{
     ast::{self, AstNode},
@@ -31,14 +31,14 @@ use syntax::{
 ///   }
 /// }
 /// ```
-pub(crate) struct PathTransform<'a> {
-    pub(crate) subst: (hir::Trait, ast::Impl),
-    pub(crate) target_scope: &'a SemanticsScope<'a>,
-    pub(crate) source_scope: &'a SemanticsScope<'a>,
+pub struct PathTransform<'a> {
+    pub subst: (hir::Trait, ast::Impl),
+    pub target_scope: &'a SemanticsScope<'a>,
+    pub source_scope: &'a SemanticsScope<'a>,
 }
 
 impl<'a> PathTransform<'a> {
-    pub(crate) fn apply(&self, item: ast::AssocItem) {
+    pub fn apply(&self, item: ast::AssocItem) {
         if let Some(ctx) = self.build_ctx() {
             ctx.apply(item)
         }
diff --git a/crates/ide_db/src/rename.rs b/crates/ide_db/src/rename.rs
new file mode 100644
index 000000000..643e67781
--- /dev/null
+++ b/crates/ide_db/src/rename.rs
@@ -0,0 +1,468 @@
+//! Rename infrastructure for rust-analyzer. It is used primarily for the
+//! literal "rename" in the ide (look for tests there), but it is also available
+//! as a general-purpose service. For example, it is used by the fix for the
+//! "incorrect case" diagnostic.
+//!
+//! It leverages the [`crate::search`] functionality to find what needs to be
+//! renamed. The actual renames are tricky -- field shorthands need special
+//! attention, and, when renaming modules, you also want to rename files on the
+//! file system.
+//!
+//! Another can of worms are macros:
+//!
+//! ```
+//! macro_rules! m { () => { fn f() {} } }
+//! m!();
+//! fn main() {
+//!     f() // <- rename me
+//! }
+//! ```
+//!
+//! The correct behavior in such cases is probably to show a dialog to the user.
+//! Our current behavior is ¯\_(ツ)_/¯.
+use std::fmt;
+
+use base_db::{AnchoredPathBuf, FileId, FileRange};
+use either::Either;
+use hir::{AsAssocItem, FieldSource, HasSource, InFile, ModuleSource, Semantics};
+use stdx::never;
+use syntax::{
+    ast::{self, NameOwner},
+    lex_single_syntax_kind, AstNode, SyntaxKind, TextRange, T,
+};
+use text_edit::TextEdit;
+
+use crate::{
+    defs::Definition,
+    search::FileReference,
+    source_change::{FileSystemEdit, SourceChange},
+    RootDatabase,
+};
+
+pub type Result<T, E = RenameError> = std::result::Result<T, E>;
+
+#[derive(Debug)]
+pub struct RenameError(pub String);
+
+impl fmt::Display for RenameError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(&self.0, f)
+    }
+}
+
+#[macro_export]
+macro_rules! _format_err {
+    ($fmt:expr) => { RenameError(format!($fmt)) };
+    ($fmt:expr, $($arg:tt)+) => { RenameError(format!($fmt, $($arg)+)) }
+}
+pub use _format_err as format_err;
+
+#[macro_export]
+macro_rules! _bail {
+    ($($tokens:tt)*) => { return Err(format_err!($($tokens)*)) }
+}
+pub use _bail as bail;
+
+impl Definition {
+    pub fn rename(&self, sema: &Semantics<RootDatabase>, new_name: &str) -> Result<SourceChange> {
+        match *self {
+            Definition::ModuleDef(hir::ModuleDef::Module(module)) => {
+                rename_mod(sema, module, new_name)
+            }
+            Definition::ModuleDef(hir::ModuleDef::BuiltinType(_)) => {
+                bail!("Cannot rename builtin type")
+            }
+            Definition::SelfType(_) => bail!("Cannot rename `Self`"),
+            def => rename_reference(sema, def, new_name),
+        }
+    }
+
+    /// Textual range of the identifier which will change when renaming this
+    /// `Definition`. Note that some definitions, like buitin types, can't be
+    /// renamed.
+    pub fn range_for_rename(self, sema: &Semantics<RootDatabase>) -> Option<FileRange> {
+        // FIXME: the `original_file_range` calls here are wrong -- they never fail,
+        // and _fall back_ to the entirety of the macro call. Such fall back is
+        // incorrect for renames. The safe behavior would be to return an error for
+        // such cases. The correct behavior would be to return an auxiliary list of
+        // "can't rename these occurrences in macros" items, and then show some kind
+        // of a dialog to the user. See:
+        cov_mark::hit!(macros_are_broken_lol);
+
+        let res = match self {
+            Definition::Macro(mac) => {
+                let src = mac.source(sema.db)?;
+                let name = match &src.value {
+                    Either::Left(it) => it.name()?,
+                    Either::Right(it) => it.name()?,
+                };
+                src.with_value(name.syntax()).original_file_range(sema.db)
+            }
+            Definition::Field(field) => {
+                let src = field.source(sema.db)?;
+
+                match &src.value {
+                    FieldSource::Named(record_field) => {
+                        let name = record_field.name()?;
+                        src.with_value(name.syntax()).original_file_range(sema.db)
+                    }
+                    FieldSource::Pos(_) => {
+                        return None;
+                    }
+                }
+            }
+            Definition::ModuleDef(module_def) => match module_def {
+                hir::ModuleDef::Module(module) => {
+                    let src = module.declaration_source(sema.db)?;
+                    let name = src.value.name()?;
+                    src.with_value(name.syntax()).original_file_range(sema.db)
+                }
+                hir::ModuleDef::Function(it) => name_range(it, sema)?,
+                hir::ModuleDef::Adt(adt) => match adt {
+                    hir::Adt::Struct(it) => name_range(it, sema)?,
+                    hir::Adt::Union(it) => name_range(it, sema)?,
+                    hir::Adt::Enum(it) => name_range(it, sema)?,
+                },
+                hir::ModuleDef::Variant(it) => name_range(it, sema)?,
+                hir::ModuleDef::Const(it) => name_range(it, sema)?,
+                hir::ModuleDef::Static(it) => name_range(it, sema)?,
+                hir::ModuleDef::Trait(it) => name_range(it, sema)?,
+                hir::ModuleDef::TypeAlias(it) => name_range(it, sema)?,
+                hir::ModuleDef::BuiltinType(_) => return None,
+            },
+            Definition::SelfType(_) => return None,
+            Definition::Local(local) => {
+                let src = local.source(sema.db);
+                let name = match &src.value {
+                    Either::Left(bind_pat) => bind_pat.name()?,
+                    Either::Right(_) => return None,
+                };
+                src.with_value(name.syntax()).original_file_range(sema.db)
+            }
+            Definition::GenericParam(generic_param) => match generic_param {
+                hir::GenericParam::TypeParam(type_param) => {
+                    let src = type_param.source(sema.db)?;
+                    let name = match &src.value {
+                        Either::Left(type_param) => type_param.name()?,
+                        Either::Right(_trait) => return None,
+                    };
+                    src.with_value(name.syntax()).original_file_range(sema.db)
+                }
+                hir::GenericParam::LifetimeParam(lifetime_param) => {
+                    let src = lifetime_param.source(sema.db)?;
+                    let lifetime = src.value.lifetime()?;
+                    src.with_value(lifetime.syntax()).original_file_range(sema.db)
+                }
+                hir::GenericParam::ConstParam(it) => name_range(it, sema)?,
+            },
+            Definition::Label(label) => {
+                let src = label.source(sema.db);
+                let lifetime = src.value.lifetime()?;
+                src.with_value(lifetime.syntax()).original_file_range(sema.db)
+            }
+        };
+        return Some(res);
+
+        fn name_range<D>(def: D, sema: &Semantics<RootDatabase>) -> Option<FileRange>
+        where
+            D: HasSource,
+            D::Ast: ast::NameOwner,
+        {
+            let src = def.source(sema.db)?;
+            let name = src.value.name()?;
+            let res = src.with_value(name.syntax()).original_file_range(sema.db);
+            Some(res)
+        }
+    }
+}
+
+fn rename_mod(
+    sema: &Semantics<RootDatabase>,
+    module: hir::Module,
+    new_name: &str,
+) -> Result<SourceChange> {
+    if IdentifierKind::classify(new_name)? != IdentifierKind::Ident {
+        bail!("Invalid name `{0}`: cannot rename module to {0}", new_name);
+    }
+
+    let mut source_change = SourceChange::default();
+
+    let InFile { file_id, value: def_source } = module.definition_source(sema.db);
+    let file_id = file_id.original_file(sema.db);
+    if let ModuleSource::SourceFile(..) = def_source {
+        // mod is defined in path/to/dir/mod.rs
+        let path = if module.is_mod_rs(sema.db) {
+            format!("../{}/mod.rs", new_name)
+        } else {
+            format!("{}.rs", new_name)
+        };
+        let dst = AnchoredPathBuf { anchor: file_id, path };
+        let move_file = FileSystemEdit::MoveFile { src: file_id, dst };
+        source_change.push_file_system_edit(move_file);
+    }
+
+    if let Some(InFile { file_id, value: decl_source }) = module.declaration_source(sema.db) {
+        let file_id = file_id.original_file(sema.db);
+        match decl_source.name() {
+            Some(name) => source_change.insert_source_edit(
+                file_id,
+                TextEdit::replace(name.syntax().text_range(), new_name.to_string()),
+            ),
+            _ => never!("Module source node is missing a name"),
+        }
+    }
+    let def = Definition::ModuleDef(hir::ModuleDef::Module(module));
+    let usages = def.usages(sema).all();
+    let ref_edits = usages.iter().map(|(&file_id, references)| {
+        (file_id, source_edit_from_references(references, def, new_name))
+    });
+    source_change.extend(ref_edits);
+
+    Ok(source_change)
+}
+
+fn rename_reference(
+    sema: &Semantics<RootDatabase>,
+    mut def: Definition,
+    new_name: &str,
+) -> Result<SourceChange> {
+    let ident_kind = IdentifierKind::classify(new_name)?;
+
+    if matches!(
+        def, // is target a lifetime?
+        Definition::GenericParam(hir::GenericParam::LifetimeParam(_)) | Definition::Label(_)
+    ) {
+        match ident_kind {
+            IdentifierKind::Ident | IdentifierKind::Underscore => {
+                cov_mark::hit!(rename_not_a_lifetime_ident_ref);
+                bail!("Invalid name `{}`: not a lifetime identifier", new_name);
+            }
+            IdentifierKind::Lifetime => cov_mark::hit!(rename_lifetime),
+        }
+    } else {
+        match (ident_kind, def) {
+            (IdentifierKind::Lifetime, _) => {
+                cov_mark::hit!(rename_not_an_ident_ref);
+                bail!("Invalid name `{}`: not an identifier", new_name);
+            }
+            (IdentifierKind::Ident, _) => cov_mark::hit!(rename_non_local),
+            (IdentifierKind::Underscore, _) => (),
+        }
+    }
+
+    def = match def {
+        // HACK: resolve trait impl items to the item def of the trait definition
+        // so that we properly resolve all trait item references
+        Definition::ModuleDef(mod_def) => mod_def
+            .as_assoc_item(sema.db)
+            .and_then(|it| it.containing_trait_impl(sema.db))
+            .and_then(|it| {
+                it.items(sema.db).into_iter().find_map(|it| match (it, mod_def) {
+                    (hir::AssocItem::Function(trait_func), hir::ModuleDef::Function(func))
+                        if trait_func.name(sema.db) == func.name(sema.db) =>
+                    {
+                        Some(Definition::ModuleDef(hir::ModuleDef::Function(trait_func)))
+                    }
+                    (hir::AssocItem::Const(trait_konst), hir::ModuleDef::Const(konst))
+                        if trait_konst.name(sema.db) == konst.name(sema.db) =>
+                    {
+                        Some(Definition::ModuleDef(hir::ModuleDef::Const(trait_konst)))
+                    }
+                    (
+                        hir::AssocItem::TypeAlias(trait_type_alias),
+                        hir::ModuleDef::TypeAlias(type_alias),
+                    ) if trait_type_alias.name(sema.db) == type_alias.name(sema.db) => {
+                        Some(Definition::ModuleDef(hir::ModuleDef::TypeAlias(trait_type_alias)))
+                    }
+                    _ => None,
+                })
+            })
+            .unwrap_or(def),
+        _ => def,
+    };
+    let usages = def.usages(sema).all();
+
+    if !usages.is_empty() && ident_kind == IdentifierKind::Underscore {
+        cov_mark::hit!(rename_underscore_multiple);
+        bail!("Cannot rename reference to `_` as it is being referenced multiple times");
+    }
+    let mut source_change = SourceChange::default();
+    source_change.extend(usages.iter().map(|(&file_id, references)| {
+        (file_id, source_edit_from_references(references, def, new_name))
+    }));
+
+    let (file_id, edit) = source_edit_from_def(sema, def, new_name)?;
+    source_change.insert_source_edit(file_id, edit);
+    Ok(source_change)
+}
+
+pub fn source_edit_from_references(
+    references: &[FileReference],
+    def: Definition,
+    new_name: &str,
+) -> TextEdit {
+    let mut edit = TextEdit::builder();
+    for reference in references {
+        let (range, replacement) = match &reference.name {
+            // if the ranges differ then the node is inside a macro call, we can't really attempt
+            // to make special rewrites like shorthand syntax and such, so just rename the node in
+            // the macro input
+            ast::NameLike::NameRef(name_ref)
+                if name_ref.syntax().text_range() == reference.range =>
+            {
+                source_edit_from_name_ref(name_ref, new_name, def)
+            }
+            ast::NameLike::Name(name) if name.syntax().text_range() == reference.range => {
+                source_edit_from_name(name, new_name)
+            }
+            _ => None,
+        }
+        .unwrap_or_else(|| (reference.range, new_name.to_string()));
+        edit.replace(range, replacement);
+    }
+    edit.finish()
+}
+
+fn source_edit_from_name(name: &ast::Name, new_name: &str) -> Option<(TextRange, String)> {
+    if let Some(_) = ast::RecordPatField::for_field_name(name) {
+        if let Some(ident_pat) = name.syntax().parent().and_then(ast::IdentPat::cast) {
+            return Some((
+                TextRange::empty(ident_pat.syntax().text_range().start()),
+                [new_name, ": "].concat(),
+            ));
+        }
+    }
+    None
+}
+
+fn source_edit_from_name_ref(
+    name_ref: &ast::NameRef,
+    new_name: &str,
+    def: Definition,
+) -> Option<(TextRange, String)> {
+    if let Some(record_field) = ast::RecordExprField::for_name_ref(name_ref) {
+        let rcf_name_ref = record_field.name_ref();
+        let rcf_expr = record_field.expr();
+        match (rcf_name_ref, rcf_expr.and_then(|it| it.name_ref())) {
+            // field: init-expr, check if we can use a field init shorthand
+            (Some(field_name), Some(init)) => {
+                if field_name == *name_ref {
+                    if init.text() == new_name {
+                        cov_mark::hit!(test_rename_field_put_init_shorthand);
+                        // same names, we can use a shorthand here instead.
+                        // we do not want to erase attributes hence this range start
+                        let s = field_name.syntax().text_range().start();
+                        let e = record_field.syntax().text_range().end();
+                        return Some((TextRange::new(s, e), new_name.to_owned()));
+                    }
+                } else if init == *name_ref {
+                    if field_name.text() == new_name {
+                        cov_mark::hit!(test_rename_local_put_init_shorthand);
+                        // same names, we can use a shorthand here instead.
+                        // we do not want to erase attributes hence this range start
+                        let s = field_name.syntax().text_range().start();
+                        let e = record_field.syntax().text_range().end();
+                        return Some((TextRange::new(s, e), new_name.to_owned()));
+                    }
+                }
+                None
+            }
+            // init shorthand
+            // FIXME: instead of splitting the shorthand, recursively trigger a rename of the
+            // other name https://github.com/rust-analyzer/rust-analyzer/issues/6547
+            (None, Some(_)) if matches!(def, Definition::Field(_)) => {
+                cov_mark::hit!(test_rename_field_in_field_shorthand);
+                let s = name_ref.syntax().text_range().start();
+                Some((TextRange::empty(s), format!("{}: ", new_name)))
+            }
+            (None, Some(_)) if matches!(def, Definition::Local(_)) => {
+                cov_mark::hit!(test_rename_local_in_field_shorthand);
+                let s = name_ref.syntax().text_range().end();
+                Some((TextRange::empty(s), format!(": {}", new_name)))
+            }
+            _ => None,
+        }
+    } else if let Some(record_field) = ast::RecordPatField::for_field_name_ref(name_ref) {
+        let rcf_name_ref = record_field.name_ref();
+        let rcf_pat = record_field.pat();
+        match (rcf_name_ref, rcf_pat) {
+            // field: rename
+            (Some(field_name), Some(ast::Pat::IdentPat(pat))) if field_name == *name_ref => {
+                // field name is being renamed
+                if pat.name().map_or(false, |it| it.text() == new_name) {
+                    cov_mark::hit!(test_rename_field_put_init_shorthand_pat);
+                    // same names, we can use a shorthand here instead/
+                    // we do not want to erase attributes hence this range start
+                    let s = field_name.syntax().text_range().start();
+                    let e = record_field.syntax().text_range().end();
+                    Some((TextRange::new(s, e), pat.to_string()))
+                } else {
+                    None
+                }
+            }
+            _ => None,
+        }
+    } else {
+        None
+    }
+}
+
+fn source_edit_from_def(
+    sema: &Semantics<RootDatabase>,
+    def: Definition,
+    new_name: &str,
+) -> Result<(FileId, TextEdit)> {
+    let frange = def
+        .range_for_rename(sema)
+        .ok_or_else(|| format_err!("No identifier available to rename"))?;
+
+    let mut replacement_text = String::new();
+    let mut repl_range = frange.range;
+    if let Definition::Local(local) = def {
+        if let Either::Left(pat) = local.source(sema.db).value {
+            if matches!(
+                pat.syntax().parent().and_then(ast::RecordPatField::cast),
+                Some(pat_field) if pat_field.name_ref().is_none()
+            ) {
+                replacement_text.push_str(": ");
+                replacement_text.push_str(new_name);
+                repl_range = TextRange::new(
+                    pat.syntax().text_range().end(),
+                    pat.syntax().text_range().end(),
+                );
+            }
+        }
+    }
+    if replacement_text.is_empty() {
+        replacement_text.push_str(new_name);
+    }
+    let edit = TextEdit::replace(repl_range, replacement_text);
+    Ok((frange.file_id, edit))
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum IdentifierKind {
+    Ident,
+    Lifetime,
+    Underscore,
+}
+
+impl IdentifierKind {
+    pub fn classify(new_name: &str) -> Result<IdentifierKind> {
+        match lex_single_syntax_kind(new_name) {
+            Some(res) => match res {
+                (SyntaxKind::IDENT, _) => Ok(IdentifierKind::Ident),
+                (T![_], _) => Ok(IdentifierKind::Underscore),
+                (SyntaxKind::LIFETIME_IDENT, _) if new_name != "'static" && new_name != "'_" => {
+                    Ok(IdentifierKind::Lifetime)
+                }
+                (SyntaxKind::LIFETIME_IDENT, _) => {
+                    bail!("Invalid name `{}`: not a lifetime identifier", new_name)
+                }
+                (_, Some(syntax_error)) => bail!("Invalid name `{}`: {}", new_name, syntax_error),
+                (_, None) => bail!("Invalid name `{}`: not an identifier", new_name),
+            },
+            None => bail!("Invalid name `{}`: not an identifier", new_name),
+        }
+    }
+}
diff --git a/crates/ide_diagnostics/Cargo.toml b/crates/ide_diagnostics/Cargo.toml
new file mode 100644
index 000000000..fa2adf212
--- /dev/null
+++ b/crates/ide_diagnostics/Cargo.toml
@@ -0,0 +1,29 @@
+[package]
+name = "ide_diagnostics"
+version = "0.0.0"
+description = "TBD"
+license = "MIT OR Apache-2.0"
+authors = ["rust-analyzer developers"]
+edition = "2018"
+
+[lib]
+doctest = false
+
+[dependencies]
+cov-mark = "2.0.0-pre.1"
+itertools = "0.10.0"
+rustc-hash = "1.1.0"
+either = "1.5.3"
+
+profile = { path = "../profile", version = "0.0.0" }
+stdx = { path = "../stdx", version = "0.0.0" }
+syntax = { path = "../syntax", version = "0.0.0" }
+text_edit = { path = "../text_edit", version = "0.0.0" }
+cfg = { path = "../cfg", version = "0.0.0" }
+hir = { path = "../hir", version = "0.0.0" }
+ide_db = { path = "../ide_db", version = "0.0.0" }
+
+[dev-dependencies]
+expect-test = "1.1"
+
+test_utils = { path = "../test_utils" }
diff --git a/crates/ide/src/diagnostics/break_outside_of_loop.rs b/crates/ide_diagnostics/src/handlers/break_outside_of_loop.rs
index 80e68f3cc..d12594a4c 100644
--- a/crates/ide/src/diagnostics/break_outside_of_loop.rs
+++ b/crates/ide_diagnostics/src/handlers/break_outside_of_loop.rs
@@ -1,9 +1,9 @@
-use crate::diagnostics::{Diagnostic, DiagnosticsContext};
+use crate::{Diagnostic, DiagnosticsContext};
 
 // Diagnostic: break-outside-of-loop
 //
 // This diagnostic is triggered if the `break` keyword is used outside of a loop.
-pub(super) fn break_outside_of_loop(
+pub(crate) fn break_outside_of_loop(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::BreakOutsideOfLoop,
 ) -> Diagnostic {
@@ -16,14 +16,14 @@ pub(super) fn break_outside_of_loop(
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::check_diagnostics;
+    use crate::tests::check_diagnostics;
 
     #[test]
     fn break_outside_of_loop() {
         check_diagnostics(
             r#"
 fn foo() { break; }
-         //^^^^^ break outside of loop
+         //^^^^^ error: break outside of loop
 "#,
         );
     }
diff --git a/crates/ide/src/diagnostics/field_shorthand.rs b/crates/ide_diagnostics/src/handlers/field_shorthand.rs
index c7f4dab8e..33152e284 100644
--- a/crates/ide/src/diagnostics/field_shorthand.rs
+++ b/crates/ide_diagnostics/src/handlers/field_shorthand.rs
@@ -5,9 +5,9 @@ use ide_db::{base_db::FileId, source_change::SourceChange};
 use syntax::{ast, match_ast, AstNode, SyntaxNode};
 use text_edit::TextEdit;
 
-use crate::{diagnostics::fix, Diagnostic, Severity};
+use crate::{fix, Diagnostic, Severity};
 
-pub(super) fn check(acc: &mut Vec<Diagnostic>, file_id: FileId, node: &SyntaxNode) {
+pub(crate) fn field_shorthand(acc: &mut Vec<Diagnostic>, file_id: FileId, node: &SyntaxNode) {
     match_ast! {
         match node {
             ast::RecordExpr(it) => check_expr_field_shorthand(acc, file_id, it),
@@ -101,7 +101,7 @@ fn check_pat_field_shorthand(
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::{check_diagnostics, check_fix};
+    use crate::tests::{check_diagnostics, check_fix};
 
     #[test]
     fn test_check_expr_field_shorthand() {
diff --git a/crates/ide/src/diagnostics/inactive_code.rs b/crates/ide_diagnostics/src/handlers/inactive_code.rs
index d9d3e88c1..dfd0e3351 100644
--- a/crates/ide/src/diagnostics/inactive_code.rs
+++ b/crates/ide_diagnostics/src/handlers/inactive_code.rs
@@ -1,15 +1,12 @@
 use cfg::DnfExpr;
 use stdx::format_to;
 
-use crate::{
-    diagnostics::{Diagnostic, DiagnosticsContext},
-    Severity,
-};
+use crate::{Diagnostic, DiagnosticsContext, Severity};
 
 // Diagnostic: inactive-code
 //
 // This diagnostic is shown for code with inactive `#[cfg]` attributes.
-pub(super) fn inactive_code(
+pub(crate) fn inactive_code(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::InactiveCode,
 ) -> Option<Diagnostic> {
@@ -37,7 +34,7 @@ pub(super) fn inactive_code(
 
 #[cfg(test)]
 mod tests {
-    use crate::{diagnostics::tests::check_diagnostics_with_config, DiagnosticsConfig};
+    use crate::{tests::check_diagnostics_with_config, DiagnosticsConfig};
 
     pub(crate) fn check(ra_fixture: &str) {
         let config = DiagnosticsConfig::default();
@@ -52,26 +49,26 @@ fn f() {
     // The three g̶e̶n̶d̶e̶r̶s̶ statements:
 
     #[cfg(a)] fn f() {}  // Item statement
-  //^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: a is disabled
+  //^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: a is disabled
     #[cfg(a)] {}         // Expression statement
-  //^^^^^^^^^^^^ code is inactive due to #[cfg] directives: a is disabled
+  //^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: a is disabled
     #[cfg(a)] let x = 0; // let statement
-  //^^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: a is disabled
+  //^^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: a is disabled
 
     abc(#[cfg(a)] 0);
-      //^^^^^^^^^^^ code is inactive due to #[cfg] directives: a is disabled
+      //^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: a is disabled
     let x = Struct {
         #[cfg(a)] f: 0,
-      //^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: a is disabled
+      //^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: a is disabled
     };
     match () {
         () => (),
         #[cfg(a)] () => (),
-      //^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: a is disabled
+      //^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: a is disabled
     }
 
     #[cfg(a)] 0          // Trailing expression of block
-  //^^^^^^^^^^^ code is inactive due to #[cfg] directives: a is disabled
+  //^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: a is disabled
 }
         "#,
         );
@@ -84,16 +81,16 @@ fn f() {
         check(
             r#"
     #[cfg(no)] pub fn f() {}
-  //^^^^^^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: no is disabled
+  //^^^^^^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: no is disabled
 
     #[cfg(no)] #[cfg(no2)] mod m;
-  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: no and no2 are disabled
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: no and no2 are disabled
 
     #[cfg(all(not(a), b))] enum E {}
-  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: b is disabled
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: b is disabled
 
     #[cfg(feature = "std")] use std;
-  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: feature = "std" is disabled
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: feature = "std" is disabled
 "#,
         );
     }
@@ -105,14 +102,14 @@ fn f() {
         check(
             r#"
     #[cfg_attr(not(never), cfg(no))] fn f() {}
-  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: no is disabled
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: no is disabled
 
     #[cfg_attr(not(never), cfg(not(no)))] fn f() {}
 
     #[cfg_attr(never, cfg(no))] fn g() {}
 
     #[cfg_attr(not(never), inline, cfg(no))] fn h() {}
-  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: no is disabled
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: no is disabled
 "#,
         );
     }
diff --git a/crates/ide/src/diagnostics/incorrect_case.rs b/crates/ide_diagnostics/src/handlers/incorrect_case.rs
index 832394400..68f25f284 100644
--- a/crates/ide/src/diagnostics/incorrect_case.rs
+++ b/crates/ide_diagnostics/src/handlers/incorrect_case.rs
@@ -1,18 +1,19 @@
 use hir::{db::AstDatabase, InFile};
-use ide_assists::Assist;
-use ide_db::base_db::FilePosition;
+use ide_db::{assists::Assist, defs::NameClass};
 use syntax::AstNode;
 
 use crate::{
-    diagnostics::{unresolved_fix, Diagnostic, DiagnosticsContext},
-    references::rename::rename_with_semantics,
+    // references::rename::rename_with_semantics,
+    unresolved_fix,
+    Diagnostic,
+    DiagnosticsContext,
     Severity,
 };
 
 // Diagnostic: incorrect-ident-case
 //
 // This diagnostic is triggered if an item name doesn't follow https://doc.rust-lang.org/1.0.0/style/style/naming/README.html[Rust naming convention].
-pub(super) fn incorrect_case(ctx: &DiagnosticsContext<'_>, d: &hir::IncorrectCase) -> Diagnostic {
+pub(crate) fn incorrect_case(ctx: &DiagnosticsContext<'_>, d: &hir::IncorrectCase) -> Diagnostic {
     Diagnostic::new(
         "incorrect-ident-case",
         format!(
@@ -28,15 +29,15 @@ pub(super) fn incorrect_case(ctx: &DiagnosticsContext<'_>, d: &hir::IncorrectCas
 fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::IncorrectCase) -> Option<Vec<Assist>> {
     let root = ctx.sema.db.parse_or_expand(d.file)?;
     let name_node = d.ident.to_node(&root);
+    let def = NameClass::classify(&ctx.sema, &name_node)?.defined(ctx.sema.db)?;
 
     let name_node = InFile::new(d.file, name_node.syntax());
     let frange = name_node.original_file_range(ctx.sema.db);
-    let file_position = FilePosition { file_id: frange.file_id, offset: frange.range.start() };
 
     let label = format!("Rename to {}", d.suggested_text);
     let mut res = unresolved_fix("change_case", &label, frange.range);
     if ctx.resolve.should_resolve(&res.id) {
-        let source_change = rename_with_semantics(&ctx.sema, file_position, &d.suggested_text);
+        let source_change = def.rename(&ctx.sema, &d.suggested_text);
         res.source_change = Some(source_change.ok().unwrap_or_default());
     }
 
@@ -45,10 +46,7 @@ fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::IncorrectCase) -> Option<Vec<Ass
 
 #[cfg(test)]
 mod change_case {
-    use crate::{
-        diagnostics::tests::{check_diagnostics, check_fix},
-        fixture, AssistResolveStrategy, DiagnosticsConfig,
-    };
+    use crate::tests::{check_diagnostics, check_fix};
 
     #[test]
     fn test_rename_incorrect_case() {
@@ -116,7 +114,7 @@ fn some_fn() {
         check_diagnostics(
             r#"
 fn foo() {
-    const ANOTHER_ITEM$0: &str = "some_item";
+    const ANOTHER_ITEM: &str = "some_item";
 }
 "#,
         );
@@ -148,20 +146,13 @@ impl TestStruct {
 
     #[test]
     fn test_single_incorrect_case_diagnostic_in_function_name_issue_6970() {
-        let input = r#"fn FOO$0() {}"#;
-        let expected = r#"fn foo() {}"#;
-
-        let (analysis, file_position) = fixture::position(input);
-        let diagnostics = analysis
-            .diagnostics(
-                &DiagnosticsConfig::default(),
-                AssistResolveStrategy::All,
-                file_position.file_id,
-            )
-            .unwrap();
-        assert_eq!(diagnostics.len(), 1);
-
-        check_fix(input, expected);
+        check_diagnostics(
+            r#"
+fn FOO() {}
+// ^^^ 💡 weak: Function `FOO` should have snake_case name, e.g. `foo`
+"#,
+        );
+        check_fix(r#"fn FOO$0() {}"#, r#"fn foo() {}"#);
     }
 
     #[test]
@@ -169,7 +160,7 @@ impl TestStruct {
         check_diagnostics(
             r#"
 fn NonSnakeCaseName() {}
-// ^^^^^^^^^^^^^^^^ Function `NonSnakeCaseName` should have snake_case name, e.g. `non_snake_case_name`
+// ^^^^^^^^^^^^^^^^ 💡 weak: Function `NonSnakeCaseName` should have snake_case name, e.g. `non_snake_case_name`
 "#,
         );
     }
@@ -179,10 +170,10 @@ fn NonSnakeCaseName() {}
         check_diagnostics(
             r#"
 fn foo(SomeParam: u8) {}
-    // ^^^^^^^^^ Parameter `SomeParam` should have snake_case name, e.g. `some_param`
+    // ^^^^^^^^^ 💡 weak: Parameter `SomeParam` should have snake_case name, e.g. `some_param`
 
 fn foo2(ok_param: &str, CAPS_PARAM: u8) {}
-                     // ^^^^^^^^^^ Parameter `CAPS_PARAM` should have snake_case name, e.g. `caps_param`
+                     // ^^^^^^^^^^ 💡 weak: Parameter `CAPS_PARAM` should have snake_case name, e.g. `caps_param`
 "#,
         );
     }
@@ -193,9 +184,9 @@ fn foo2(ok_param: &str, CAPS_PARAM: u8) {}
             r#"
 fn foo() {
     let SOME_VALUE = 10;
-     // ^^^^^^^^^^ Variable `SOME_VALUE` should have snake_case name, e.g. `some_value`
+     // ^^^^^^^^^^ 💡 weak: Variable `SOME_VALUE` should have snake_case name, e.g. `some_value`
     let AnotherValue = 20;
-     // ^^^^^^^^^^^^ Variable `AnotherValue` should have snake_case name, e.g. `another_value`
+     // ^^^^^^^^^^^^ 💡 weak: Variable `AnotherValue` should have snake_case name, e.g. `another_value`
 }
 "#,
         );
@@ -206,10 +197,10 @@ fn foo() {
         check_diagnostics(
             r#"
 struct non_camel_case_name {}
-    // ^^^^^^^^^^^^^^^^^^^ Structure `non_camel_case_name` should have CamelCase name, e.g. `NonCamelCaseName`
+    // ^^^^^^^^^^^^^^^^^^^ 💡 weak: Structure `non_camel_case_name` should have CamelCase name, e.g. `NonCamelCaseName`
 
 struct SCREAMING_CASE {}
-    // ^^^^^^^^^^^^^^ Structure `SCREAMING_CASE` should have CamelCase name, e.g. `ScreamingCase`
+    // ^^^^^^^^^^^^^^ 💡 weak: Structure `SCREAMING_CASE` should have CamelCase name, e.g. `ScreamingCase`
 "#,
         );
     }
@@ -228,7 +219,7 @@ struct AABB {}
         check_diagnostics(
             r#"
 struct SomeStruct { SomeField: u8 }
-                 // ^^^^^^^^^ Field `SomeField` should have snake_case name, e.g. `some_field`
+                 // ^^^^^^^^^ 💡 weak: Field `SomeField` should have snake_case name, e.g. `some_field`
 "#,
         );
     }
@@ -238,10 +229,10 @@ struct SomeStruct { SomeField: u8 }
         check_diagnostics(
             r#"
 enum some_enum { Val(u8) }
-  // ^^^^^^^^^ Enum `some_enum` should have CamelCase name, e.g. `SomeEnum`
+  // ^^^^^^^^^ 💡 weak: Enum `some_enum` should have CamelCase name, e.g. `SomeEnum`
 
 enum SOME_ENUM {}
-  // ^^^^^^^^^ Enum `SOME_ENUM` should have CamelCase name, e.g. `SomeEnum`
+  // ^^^^^^^^^ 💡 weak: Enum `SOME_ENUM` should have CamelCase name, e.g. `SomeEnum`
 "#,
         );
     }
@@ -260,7 +251,7 @@ enum AABB {}
         check_diagnostics(
             r#"
 enum SomeEnum { SOME_VARIANT(u8) }
-             // ^^^^^^^^^^^^ Variant `SOME_VARIANT` should have CamelCase name, e.g. `SomeVariant`
+             // ^^^^^^^^^^^^ 💡 weak: Variant `SOME_VARIANT` should have CamelCase name, e.g. `SomeVariant`
 "#,
         );
     }
@@ -270,7 +261,7 @@ enum SomeEnum { SOME_VARIANT(u8) }
         check_diagnostics(
             r#"
 const some_weird_const: u8 = 10;
-   // ^^^^^^^^^^^^^^^^ Constant `some_weird_const` should have UPPER_SNAKE_CASE name, e.g. `SOME_WEIRD_CONST`
+   // ^^^^^^^^^^^^^^^^ 💡 weak: Constant `some_weird_const` should have UPPER_SNAKE_CASE name, e.g. `SOME_WEIRD_CONST`
 "#,
         );
     }
@@ -280,7 +271,7 @@ const some_weird_const: u8 = 10;
         check_diagnostics(
             r#"
 static some_weird_const: u8 = 10;
-    // ^^^^^^^^^^^^^^^^ Static variable `some_weird_const` should have UPPER_SNAKE_CASE name, e.g. `SOME_WEIRD_CONST`
+    // ^^^^^^^^^^^^^^^^ 💡 weak: Static variable `some_weird_const` should have UPPER_SNAKE_CASE name, e.g. `SOME_WEIRD_CONST`
 "#,
         );
     }
@@ -290,13 +281,13 @@ static some_weird_const: u8 = 10;
         check_diagnostics(
             r#"
 struct someStruct;
-    // ^^^^^^^^^^ Structure `someStruct` should have CamelCase name, e.g. `SomeStruct`
+    // ^^^^^^^^^^ 💡 weak: Structure `someStruct` should have CamelCase name, e.g. `SomeStruct`
 
 impl someStruct {
     fn SomeFunc(&self) {
-    // ^^^^^^^^ Function `SomeFunc` should have snake_case name, e.g. `some_func`
+    // ^^^^^^^^ 💡 weak: Function `SomeFunc` should have snake_case name, e.g. `some_func`
         let WHY_VAR_IS_CAPS = 10;
-         // ^^^^^^^^^^^^^^^ Variable `WHY_VAR_IS_CAPS` should have snake_case name, e.g. `why_var_is_caps`
+         // ^^^^^^^^^^^^^^^ 💡 weak: Variable `WHY_VAR_IS_CAPS` should have snake_case name, e.g. `why_var_is_caps`
     }
 }
 "#,
@@ -328,7 +319,7 @@ enum Option { Some, None }
 fn main() {
     match Option::None {
         SOME_VAR @ None => (),
-     // ^^^^^^^^ Variable `SOME_VAR` should have snake_case name, e.g. `some_var`
+     // ^^^^^^^^ 💡 weak: Variable `SOME_VAR` should have snake_case name, e.g. `some_var`
         Some => (),
     }
 }
@@ -350,43 +341,27 @@ mod F {
     }
 
     #[test]
-    #[ignore]
-    fn bug_trait_inside_fn() {
-        // FIXME:
-        // This is broken, and in fact, should not even be looked at by this
-        // lint in the first place. There's weird stuff going on in the
-        // collection phase.
-        // It's currently being brought in by:
-        // * validate_func on `a` recursing into modules
-        // * then it finds the trait and then the function while iterating
-        //   through modules
-        // * then validate_func is called on Dirty
-        // * ... which then proceeds to look at some unknown module taking no
-        //   attrs from either the impl or the fn a, and then finally to the root
-        //   module
-        //
-        // It should find the attribute on the trait, but it *doesn't even see
-        // the trait* as far as I can tell.
-
+    fn complex_ignore() {
+        // FIXME: this should trigger errors for the second case.
         check_diagnostics(
             r#"
 trait T { fn a(); }
 struct U {}
 impl T for U {
     fn a() {
-        // this comes out of bitflags, mostly
         #[allow(non_snake_case)]
-        trait __BitFlags {
+        trait __BitFlagsOk {
             const HiImAlsoBad: u8 = 2;
-            #[inline]
-            fn Dirty(&self) -> bool {
-                false
-            }
+            fn Dirty(&self) -> bool { false }
         }
 
+        trait __BitFlagsBad {
+            const HiImAlsoBad: u8 = 2;
+            fn Dirty(&self) -> bool { false }
+        }
     }
 }
-    "#,
+"#,
         );
     }
 
@@ -423,18 +398,14 @@ extern {
     }
 
     #[test]
-    #[ignore]
     fn bug_traits_arent_checked() {
         // FIXME: Traits and functions in traits aren't currently checked by
         // r-a, even though rustc will complain about them.
         check_diagnostics(
             r#"
 trait BAD_TRAIT {
-    // ^^^^^^^^^ Trait `BAD_TRAIT` should have CamelCase name, e.g. `BadTrait`
     fn BAD_FUNCTION();
-    // ^^^^^^^^^^^^ Function `BAD_FUNCTION` should have snake_case name, e.g. `bad_function`
     fn BadFunction();
-    // ^^^^^^^^^^^^ Function `BadFunction` should have snake_case name, e.g. `bad_function`
 }
     "#,
         );
diff --git a/crates/ide/src/diagnostics/macro_error.rs b/crates/ide_diagnostics/src/handlers/macro_error.rs
index 5f97f190d..356f089b2 100644
--- a/crates/ide/src/diagnostics/macro_error.rs
+++ b/crates/ide_diagnostics/src/handlers/macro_error.rs
@@ -1,9 +1,9 @@
-use crate::diagnostics::{Diagnostic, DiagnosticsContext};
+use crate::{Diagnostic, DiagnosticsContext};
 
 // Diagnostic: macro-error
 //
 // This diagnostic is shown for macro expansion errors.
-pub(super) fn macro_error(ctx: &DiagnosticsContext<'_>, d: &hir::MacroError) -> Diagnostic {
+pub(crate) fn macro_error(ctx: &DiagnosticsContext<'_>, d: &hir::MacroError) -> Diagnostic {
     Diagnostic::new(
         "macro-error",
         d.message.clone(),
@@ -15,7 +15,7 @@ pub(super) fn macro_error(ctx: &DiagnosticsContext<'_>, d: &hir::MacroError) ->
 #[cfg(test)]
 mod tests {
     use crate::{
-        diagnostics::tests::{check_diagnostics, check_diagnostics_with_config},
+        tests::{check_diagnostics, check_diagnostics_with_config},
         DiagnosticsConfig,
     };
 
@@ -27,7 +27,7 @@ mod tests {
 macro_rules! include { () => {} }
 
   include!("doesntexist");
-//^^^^^^^^^^^^^^^^^^^^^^^^ failed to load file `doesntexist`
+//^^^^^^^^^^^^^^^^^^^^^^^^ error: failed to load file `doesntexist`
             "#,
         );
     }
@@ -66,7 +66,7 @@ macro_rules! env { () => {} }
 macro_rules! concat { () => {} }
 
   include!(concat!(env!("OUT_DIR"), "/out.rs"));
-//^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `OUT_DIR` not set, enable "run build scripts" to fix
+//^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: `OUT_DIR` not set, enable "run build scripts" to fix
 "#,
         );
     }
@@ -108,23 +108,23 @@ fn main() {
     // Test a handful of built-in (eager) macros:
 
     include!(invalid);
-  //^^^^^^^^^^^^^^^^^ could not convert tokens
+  //^^^^^^^^^^^^^^^^^ error: could not convert tokens
     include!("does not exist");
-  //^^^^^^^^^^^^^^^^^^^^^^^^^^ failed to load file `does not exist`
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^ error: failed to load file `does not exist`
 
     env!(invalid);
-  //^^^^^^^^^^^^^ could not convert tokens
+  //^^^^^^^^^^^^^ error: could not convert tokens
 
     env!("OUT_DIR");
-  //^^^^^^^^^^^^^^^ `OUT_DIR` not set, enable "run build scripts" to fix
+  //^^^^^^^^^^^^^^^ error: `OUT_DIR` not set, enable "run build scripts" to fix
 
     compile_error!("compile_error works");
-  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ compile_error works
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: compile_error works
 
     // Lazy:
 
     format_args!();
-  //^^^^^^^^^^^^^^ no rule matches input tokens
+  //^^^^^^^^^^^^^^ error: no rule matches input tokens
 }
 "#,
         );
@@ -141,7 +141,7 @@ fn f() {
     m!();
 
     m!(hi);
-  //^^^^^^ leftover tokens
+  //^^^^^^ error: leftover tokens
 }
       "#,
         );
@@ -166,7 +166,7 @@ macro_rules! outer {
 
 fn f() {
     outer!();
-} //^^^^^^^^ leftover tokens
+} //^^^^^^^^ error: leftover tokens
 "#,
         )
     }
diff --git a/crates/ide/src/diagnostics/mismatched_arg_count.rs b/crates/ide_diagnostics/src/handlers/mismatched_arg_count.rs
index 08e1cfa5f..a9b6d3870 100644
--- a/crates/ide/src/diagnostics/mismatched_arg_count.rs
+++ b/crates/ide_diagnostics/src/handlers/mismatched_arg_count.rs
@@ -1,9 +1,9 @@
-use crate::diagnostics::{Diagnostic, DiagnosticsContext};
+use crate::{Diagnostic, DiagnosticsContext};
 
 // Diagnostic: mismatched-arg-count
 //
 // This diagnostic is triggered if a function is invoked with an incorrect amount of arguments.
-pub(super) fn mismatched_arg_count(
+pub(crate) fn mismatched_arg_count(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::MismatchedArgCount,
 ) -> Diagnostic {
@@ -18,7 +18,7 @@ pub(super) fn mismatched_arg_count(
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::check_diagnostics;
+    use crate::tests::check_diagnostics;
 
     #[test]
     fn simple_free_fn_zero() {
@@ -26,7 +26,7 @@ mod tests {
             r#"
 fn zero() {}
 fn f() { zero(1); }
-       //^^^^^^^ expected 0 arguments, found 1
+       //^^^^^^^ error: expected 0 arguments, found 1
 "#,
         );
 
@@ -44,7 +44,7 @@ fn f() { zero(); }
             r#"
 fn one(arg: u8) {}
 fn f() { one(); }
-       //^^^^^ expected 1 argument, found 0
+       //^^^^^ error: expected 1 argument, found 0
 "#,
         );
 
@@ -65,7 +65,7 @@ impl S { fn method(&self) {} }
 
 fn f() {
     S::method();
-} //^^^^^^^^^^^ expected 1 argument, found 0
+} //^^^^^^^^^^^ error: expected 1 argument, found 0
 "#,
         );
 
@@ -91,7 +91,7 @@ impl S { fn method(&self, arg: u8) {} }
 
             fn f() {
                 S.method();
-            } //^^^^^^^^^^ expected 1 argument, found 0
+            } //^^^^^^^^^^ error: expected 1 argument, found 0
             "#,
         );
 
@@ -131,7 +131,7 @@ fn f() {
 struct Tup(u8, u16);
 fn f() {
     Tup(0);
-} //^^^^^^ expected 2 arguments, found 1
+} //^^^^^^ error: expected 2 arguments, found 1
 "#,
         )
     }
@@ -143,7 +143,7 @@ fn f() {
 enum En { Variant(u8, u16), }
 fn f() {
     En::Variant(0);
-} //^^^^^^^^^^^^^^ expected 2 arguments, found 1
+} //^^^^^^^^^^^^^^ error: expected 2 arguments, found 1
 "#,
         )
     }
@@ -162,9 +162,9 @@ impl Foo {
     fn new() {
         Foo::Bar(0);
         Foo::Bar(0, 1);
-      //^^^^^^^^^^^^^^ expected 1 argument, found 2
+      //^^^^^^^^^^^^^^ error: expected 1 argument, found 2
         Foo::Bar();
-      //^^^^^^^^^^ expected 1 argument, found 0
+      //^^^^^^^^^^ error: expected 1 argument, found 0
     }
 }
         "#,
@@ -185,7 +185,7 @@ fn f() {
     unsafe {
         fixed(0);
         fixed(0, 1);
-      //^^^^^^^^^^^ expected 1 argument, found 2
+      //^^^^^^^^^^^ error: expected 1 argument, found 2
         varargs(0);
         varargs(0, 1);
         varargs2();
@@ -204,10 +204,10 @@ fn f() {
 fn main() {
     let f = |()| ();
     f();
-  //^^^ expected 1 argument, found 0
+  //^^^ error: expected 1 argument, found 0
     f(());
     f((), ());
-  //^^^^^^^^^ expected 1 argument, found 2
+  //^^^^^^^^^ error: expected 1 argument, found 2
 }
 "#,
         )
diff --git a/crates/ide/src/diagnostics/missing_fields.rs b/crates/ide_diagnostics/src/handlers/missing_fields.rs
index d01f05041..bc56e0342 100644
--- a/crates/ide/src/diagnostics/missing_fields.rs
+++ b/crates/ide_diagnostics/src/handlers/missing_fields.rs
@@ -1,12 +1,11 @@
 use either::Either;
 use hir::{db::AstDatabase, InFile};
-use ide_assists::Assist;
-use ide_db::source_change::SourceChange;
+use ide_db::{assists::Assist, source_change::SourceChange};
 use stdx::format_to;
 use syntax::{algo, ast::make, AstNode, SyntaxNodePtr};
 use text_edit::TextEdit;
 
-use crate::diagnostics::{fix, Diagnostic, DiagnosticsContext};
+use crate::{fix, Diagnostic, DiagnosticsContext};
 
 // Diagnostic: missing-fields
 //
@@ -19,8 +18,8 @@ use crate::diagnostics::{fix, Diagnostic, DiagnosticsContext};
 //
 // let a = A { a: 10 };
 // ```
-pub(super) fn missing_fields(ctx: &DiagnosticsContext<'_>, d: &hir::MissingFields) -> Diagnostic {
-    let mut message = String::from("Missing structure fields:\n");
+pub(crate) fn missing_fields(ctx: &DiagnosticsContext<'_>, d: &hir::MissingFields) -> Diagnostic {
+    let mut message = String::from("missing structure fields:\n");
     for field in &d.missed_fields {
         format_to!(message, "- {}\n", field);
     }
@@ -77,7 +76,7 @@ fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::MissingFields) -> Option<Vec<Ass
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::{check_diagnostics, check_fix};
+    use crate::tests::{check_diagnostics, check_fix};
 
     #[test]
     fn missing_record_pat_field_diagnostic() {
@@ -86,7 +85,7 @@ mod tests {
 struct S { foo: i32, bar: () }
 fn baz(s: S) {
     let S { foo: _ } = s;
-      //^ Missing structure fields:
+      //^ error: missing structure fields:
       //| - bar
 }
 "#,
@@ -324,4 +323,33 @@ fn f() {
 "#,
         );
     }
+
+    #[test]
+    fn import_extern_crate_clash_with_inner_item() {
+        // This is more of a resolver test, but doesn't really work with the hir_def testsuite.
+
+        check_diagnostics(
+            r#"
+//- /lib.rs crate:lib deps:jwt
+mod permissions;
+
+use permissions::jwt;
+
+fn f() {
+    fn inner() {}
+    jwt::Claims {}; // should resolve to the local one with 0 fields, and not get a diagnostic
+}
+
+//- /permissions.rs
+pub mod jwt  {
+    pub struct Claims {}
+}
+
+//- /jwt/lib.rs crate:jwt
+pub struct Claims {
+    field: u8,
+}
+        "#,
+        );
+    }
 }
diff --git a/crates/ide/src/diagnostics/missing_match_arms.rs b/crates/ide_diagnostics/src/handlers/missing_match_arms.rs
index b636489b3..947b0f2e2 100644
--- a/crates/ide/src/diagnostics/missing_match_arms.rs
+++ b/crates/ide_diagnostics/src/handlers/missing_match_arms.rs
@@ -1,11 +1,11 @@
 use hir::InFile;
 
-use crate::diagnostics::{Diagnostic, DiagnosticsContext};
+use crate::{Diagnostic, DiagnosticsContext};
 
 // Diagnostic: missing-match-arm
 //
 // This diagnostic is triggered if `match` block is missing one or more match arms.
-pub(super) fn missing_match_arms(
+pub(crate) fn missing_match_arms(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::MissingMatchArms,
 ) -> Diagnostic {
@@ -17,12 +17,12 @@ pub(super) fn missing_match_arms(
 }
 
 #[cfg(test)]
-pub(super) mod tests {
-    use crate::diagnostics::tests::check_diagnostics;
+mod tests {
+    use crate::tests::check_diagnostics;
 
     fn check_diagnostics_no_bails(ra_fixture: &str) {
         cov_mark::check_count!(validate_match_bailed_out, 0);
-        crate::diagnostics::tests::check_diagnostics(ra_fixture)
+        crate::tests::check_diagnostics(ra_fixture)
     }
 
     #[test]
@@ -31,9 +31,9 @@ pub(super) mod tests {
             r#"
 fn main() {
     match () { }
-        //^^ missing match arm
+        //^^ error: missing match arm
     match (()) { }
-        //^^^^ missing match arm
+        //^^^^ error: missing match arm
 
     match () { _ => (), }
     match () { () => (), }
@@ -49,7 +49,7 @@ fn main() {
             r#"
 fn main() {
     match ((), ()) { }
-        //^^^^^^^^ missing match arm
+        //^^^^^^^^ error: missing match arm
 
     match ((), ()) { ((), ()) => (), }
 }
@@ -63,21 +63,21 @@ fn main() {
             r#"
 fn test_main() {
     match false { }
-        //^^^^^ missing match arm
+        //^^^^^ error: missing match arm
     match false { true => (), }
-        //^^^^^ missing match arm
+        //^^^^^ error: missing match arm
     match (false, true) {}
-        //^^^^^^^^^^^^^ missing match arm
+        //^^^^^^^^^^^^^ error: missing match arm
     match (false, true) { (true, true) => (), }
-        //^^^^^^^^^^^^^ missing match arm
+        //^^^^^^^^^^^^^ error: missing match arm
     match (false, true) {
-        //^^^^^^^^^^^^^ missing match arm
+        //^^^^^^^^^^^^^ error: missing match arm
         (false, true) => (),
         (false, false) => (),
         (true, false) => (),
     }
     match (false, true) { (true, _x) => (), }
-        //^^^^^^^^^^^^^ missing match arm
+        //^^^^^^^^^^^^^ error: missing match arm
 
     match false { true => (), false => (), }
     match (false, true) {
@@ -116,11 +116,11 @@ fn test_main() {
             r#"
 fn main() {
     match (false, ((), false)) {}
-        //^^^^^^^^^^^^^^^^^^^^ missing match arm
+        //^^^^^^^^^^^^^^^^^^^^ error: missing match arm
     match (false, ((), false)) { (true, ((), true)) => (), }
-        //^^^^^^^^^^^^^^^^^^^^ missing match arm
+        //^^^^^^^^^^^^^^^^^^^^ error: missing match arm
     match (false, ((), false)) { (true, _) => (), }
-        //^^^^^^^^^^^^^^^^^^^^ missing match arm
+        //^^^^^^^^^^^^^^^^^^^^ error: missing match arm
 
     match (false, ((), false)) {
         (true, ((), true)) => (),
@@ -146,12 +146,12 @@ enum Either { A, B, }
 
 fn main() {
     match Either::A { }
-        //^^^^^^^^^ missing match arm
+        //^^^^^^^^^ error: missing match arm
     match Either::B { Either::A => (), }
-        //^^^^^^^^^ missing match arm
+        //^^^^^^^^^ error: missing match arm
 
     match &Either::B {
-        //^^^^^^^^^^ missing match arm
+        //^^^^^^^^^^ error: missing match arm
         Either::A => (),
     }
 
@@ -174,9 +174,9 @@ enum Either { A(bool), B }
 
 fn main() {
     match Either::B { }
-        //^^^^^^^^^ missing match arm
+        //^^^^^^^^^ error: missing match arm
     match Either::B {
-        //^^^^^^^^^ missing match arm
+        //^^^^^^^^^ error: missing match arm
         Either::A(true) => (), Either::B => ()
     }
 
@@ -207,7 +207,7 @@ enum Either { A(bool), B(bool, bool) }
 
 fn main() {
     match Either::A(false) {
-        //^^^^^^^^^^^^^^^^ missing match arm
+        //^^^^^^^^^^^^^^^^ error: missing match arm
         Either::A(_) => (),
         Either::B(false, _) => (),
     }
@@ -352,7 +352,7 @@ fn main() {
         Either::A => (),
     }
     match loop { break Foo::A } {
-        //^^^^^^^^^^^^^^^^^^^^^ missing match arm
+        //^^^^^^^^^^^^^^^^^^^^^ error: missing match arm
         Either::A => (),
     }
     match loop { break Foo::A } {
@@ -390,19 +390,19 @@ enum Either { A { foo: bool }, B }
 fn main() {
     let a = Either::A { foo: true };
     match a { }
-        //^ missing match arm
+        //^ error: missing match arm
     match a { Either::A { foo: true } => () }
-        //^ missing match arm
+        //^ error: missing match arm
     match a {
         Either::A { } => (),
-      //^^^^^^^^^ Missing structure fields:
+      //^^^^^^^^^ error: missing structure fields:
       //        | - foo
         Either::B => (),
     }
     match a {
-        //^ missing match arm
+        //^ error: missing match arm
         Either::A { } => (),
-    } //^^^^^^^^^ Missing structure fields:
+    } //^^^^^^^^^ error: missing structure fields:
       //        | - foo
 
     match a {
@@ -431,7 +431,7 @@ enum Either {
 fn main() {
     let a = Either::A { foo: true, bar: () };
     match a {
-        //^ missing match arm
+        //^ error: missing match arm
         Either::A { bar: (), foo: false } => (),
         Either::A { foo: true, bar: () } => (),
     }
@@ -458,12 +458,12 @@ enum Either {
 fn main() {
     let a = Either::B;
     match a {
-        //^ missing match arm
+        //^ error: missing match arm
         Either::A { foo: true, .. } => (),
         Either::B => (),
     }
     match a {
-        //^ missing match arm
+        //^ error: missing match arm
         Either::A { .. } => (),
     }
 
@@ -493,14 +493,14 @@ enum Either {
 
 fn main() {
     match Either::B {
-        //^^^^^^^^^ missing match arm
+        //^^^^^^^^^ error: missing match arm
         Either::A(true, .., true) => (),
         Either::A(true, .., false) => (),
         Either::A(false, .., false) => (),
         Either::B => (),
     }
     match Either::B {
-        //^^^^^^^^^ missing match arm
+        //^^^^^^^^^ error: missing match arm
         Either::A(true, .., true) => (),
         Either::A(true, .., false) => (),
         Either::A(.., true) => (),
@@ -537,7 +537,7 @@ fn enum_(never: Never) {
 }
 fn enum_ref(never: &Never) {
     match never {}
-        //^^^^^ missing match arm
+        //^^^^^ error: missing match arm
 }
 fn bang(never: !) {
     match never {}
@@ -561,7 +561,7 @@ fn main() {
         Some(never) => match never {},
     }
     match Option::<Never>::None {
-        //^^^^^^^^^^^^^^^^^^^^^ missing match arm
+        //^^^^^^^^^^^^^^^^^^^^^ error: missing match arm
         Option::Some(_never) => {},
     }
 }
@@ -575,7 +575,7 @@ fn main() {
             r#"
 fn main() {
     match (false, true, false) {
-        //^^^^^^^^^^^^^^^^^^^^ missing match arm
+        //^^^^^^^^^^^^^^^^^^^^ error: missing match arm
         (false, ..) => (),
     }
 }"#,
@@ -588,7 +588,7 @@ fn main() {
             r#"
 fn main() {
     match (false, true, false) {
-        //^^^^^^^^^^^^^^^^^^^^ missing match arm
+        //^^^^^^^^^^^^^^^^^^^^ error: missing match arm
         (.., false) => (),
     }
 }"#,
@@ -601,7 +601,7 @@ fn main() {
             r#"
 fn main() {
     match (false, true, false) {
-        //^^^^^^^^^^^^^^^^^^^^ missing match arm
+        //^^^^^^^^^^^^^^^^^^^^ error: missing match arm
         (true, .., false) => (),
     }
 }"#,
@@ -614,11 +614,11 @@ fn main() {
             r#"struct Foo { a: bool }
 fn main(f: Foo) {
     match f {}
-        //^ missing match arm
+        //^ error: missing match arm
     match f { Foo { a: true } => () }
-        //^ missing match arm
+        //^ error: missing match arm
     match &f { Foo { a: true } => () }
-        //^^ missing match arm
+        //^^ error: missing match arm
     match f { Foo { a: _ } => () }
     match f {
         Foo { a: true } => (),
@@ -639,9 +639,9 @@ fn main(f: Foo) {
             r#"struct Foo(bool);
 fn main(f: Foo) {
     match f {}
-        //^ missing match arm
+        //^ error: missing match arm
     match f { Foo(true) => () }
-        //^ missing match arm
+        //^ error: missing match arm
     match f {
         Foo(true) => (),
         Foo(false) => (),
@@ -657,7 +657,7 @@ fn main(f: Foo) {
             r#"struct Foo;
 fn main(f: Foo) {
     match f {}
-        //^ missing match arm
+        //^ error: missing match arm
     match f { Foo => () }
 }
 "#,
@@ -670,9 +670,9 @@ fn main(f: Foo) {
             r#"struct Foo { foo: bool, bar: bool }
 fn main(f: Foo) {
     match f { Foo { foo: true, .. } => () }
-        //^ missing match arm
+        //^ error: missing match arm
     match f {
-        //^ missing match arm
+        //^ error: missing match arm
         Foo { foo: true, .. } => (),
         Foo { bar: false, .. } => ()
     }
@@ -693,7 +693,7 @@ fn main(f: Foo) {
 fn main() {
     enum Either { A(bool), B }
     match Either::B {
-        //^^^^^^^^^ missing match arm
+        //^^^^^^^^^ error: missing match arm
         Either::A(true | false) => (),
     }
 }
@@ -715,7 +715,7 @@ fn main(v: S) {
     match v { S{..}       => {} }
     match v { _           => {} }
     match v { }
-        //^ missing match arm
+        //^ error: missing match arm
 }
 "#,
         );
@@ -731,7 +731,7 @@ fn main() {
         false     => {}
     }
     match true { _x @ true => {} }
-        //^^^^ missing match arm
+        //^^^^ error: missing match arm
 }
 "#,
         );
@@ -786,12 +786,12 @@ use lib::E;
 fn main() {
     match E::A { _ => {} }
     match E::A {
-        //^^^^ missing match arm
+        //^^^^ error: missing match arm
         E::A => {}
         E::B => {}
     }
     match E::A {
-        //^^^^ missing match arm
+        //^^^^ error: missing match arm
         E::A | E::B => {}
     }
 }
@@ -810,7 +810,7 @@ fn main() {
         false         => {}
     }
     match true {
-        //^^^^ missing match arm
+        //^^^^ error: missing match arm
         true if false => {}
         false         => {}
     }
diff --git a/crates/ide/src/diagnostics/missing_ok_or_some_in_tail_expr.rs b/crates/ide_diagnostics/src/handlers/missing_ok_or_some_in_tail_expr.rs
index 06005d156..c0edcd7d3 100644
--- a/crates/ide/src/diagnostics/missing_ok_or_some_in_tail_expr.rs
+++ b/crates/ide_diagnostics/src/handlers/missing_ok_or_some_in_tail_expr.rs
@@ -1,10 +1,9 @@
 use hir::db::AstDatabase;
-use ide_assists::Assist;
-use ide_db::source_change::SourceChange;
+use ide_db::{assists::Assist, source_change::SourceChange};
 use syntax::AstNode;
 use text_edit::TextEdit;
 
-use crate::diagnostics::{fix, Diagnostic, DiagnosticsContext};
+use crate::{fix, Diagnostic, DiagnosticsContext};
 
 // Diagnostic: missing-ok-or-some-in-tail-expr
 //
@@ -18,7 +17,7 @@ use crate::diagnostics::{fix, Diagnostic, DiagnosticsContext};
 //     10
 // }
 // ```
-pub(super) fn missing_ok_or_some_in_tail_expr(
+pub(crate) fn missing_ok_or_some_in_tail_expr(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::MissingOkOrSomeInTailExpr,
 ) -> Diagnostic {
@@ -44,32 +43,21 @@ fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::MissingOkOrSomeInTailExpr) -> Op
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::{check_diagnostics, check_fix};
+    use crate::tests::{check_diagnostics, check_fix};
 
     #[test]
     fn test_wrap_return_type_option() {
         check_fix(
             r#"
-//- /main.rs crate:main deps:core
-use core::option::Option::{self, Some, None};
-
+//- minicore: option, result
 fn div(x: i32, y: i32) -> Option<i32> {
     if y == 0 {
         return None;
     }
     x / y$0
 }
-//- /core/lib.rs crate:core
-pub mod result {
-    pub enum Result<T, E> { Ok(T), Err(E) }
-}
-pub mod option {
-    pub enum Option<T> { Some(T), None }
-}
 "#,
             r#"
-use core::option::Option::{self, Some, None};
-
 fn div(x: i32, y: i32) -> Option<i32> {
     if y == 0 {
         return None;
@@ -84,26 +72,15 @@ fn div(x: i32, y: i32) -> Option<i32> {
     fn test_wrap_return_type() {
         check_fix(
             r#"
-//- /main.rs crate:main deps:core
-use core::result::Result::{self, Ok, Err};
-
+//- minicore: option, result
 fn div(x: i32, y: i32) -> Result<i32, ()> {
     if y == 0 {
         return Err(());
     }
     x / y$0
 }
-//- /core/lib.rs crate:core
-pub mod result {
-    pub enum Result<T, E> { Ok(T), Err(E) }
-}
-pub mod option {
-    pub enum Option<T> { Some(T), None }
-}
 "#,
             r#"
-use core::result::Result::{self, Ok, Err};
-
 fn div(x: i32, y: i32) -> Result<i32, ()> {
     if y == 0 {
         return Err(());
@@ -118,26 +95,15 @@ fn div(x: i32, y: i32) -> Result<i32, ()> {
     fn test_wrap_return_type_handles_generic_functions() {
         check_fix(
             r#"
-//- /main.rs crate:main deps:core
-use core::result::Result::{self, Ok, Err};
-
+//- minicore: option, result
 fn div<T>(x: T) -> Result<T, i32> {
     if x == 0 {
         return Err(7);
     }
     $0x
 }
-//- /core/lib.rs crate:core
-pub mod result {
-    pub enum Result<T, E> { Ok(T), Err(E) }
-}
-pub mod option {
-    pub enum Option<T> { Some(T), None }
-}
 "#,
             r#"
-use core::result::Result::{self, Ok, Err};
-
 fn div<T>(x: T) -> Result<T, i32> {
     if x == 0 {
         return Err(7);
@@ -152,9 +118,7 @@ fn div<T>(x: T) -> Result<T, i32> {
     fn test_wrap_return_type_handles_type_aliases() {
         check_fix(
             r#"
-//- /main.rs crate:main deps:core
-use core::result::Result::{self, Ok, Err};
-
+//- minicore: option, result
 type MyResult<T> = Result<T, ()>;
 
 fn div(x: i32, y: i32) -> MyResult<i32> {
@@ -163,17 +127,8 @@ fn div(x: i32, y: i32) -> MyResult<i32> {
     }
     x $0/ y
 }
-//- /core/lib.rs crate:core
-pub mod result {
-    pub enum Result<T, E> { Ok(T), Err(E) }
-}
-pub mod option {
-    pub enum Option<T> { Some(T), None }
-}
 "#,
             r#"
-use core::result::Result::{self, Ok, Err};
-
 type MyResult<T> = Result<T, ()>;
 
 fn div(x: i32, y: i32) -> MyResult<i32> {
@@ -190,18 +145,8 @@ fn div(x: i32, y: i32) -> MyResult<i32> {
     fn test_wrap_return_type_not_applicable_when_expr_type_does_not_match_ok_type() {
         check_diagnostics(
             r#"
-//- /main.rs crate:main deps:core
-use core::result::Result::{self, Ok, Err};
-
+//- minicore: option, result
 fn foo() -> Result<(), i32> { 0 }
-
-//- /core/lib.rs crate:core
-pub mod result {
-    pub enum Result<T, E> { Ok(T), Err(E) }
-}
-pub mod option {
-    pub enum Option<T> { Some(T), None }
-}
 "#,
         );
     }
@@ -210,20 +155,10 @@ pub mod option {
     fn test_wrap_return_type_not_applicable_when_return_type_is_not_result_or_option() {
         check_diagnostics(
             r#"
-//- /main.rs crate:main deps:core
-use core::result::Result::{self, Ok, Err};
-
+//- minicore: option, result
 enum SomeOtherEnum { Ok(i32), Err(String) }
 
 fn foo() -> SomeOtherEnum { 0 }
-
-//- /core/lib.rs crate:core
-pub mod result {
-    pub enum Result<T, E> { Ok(T), Err(E) }
-}
-pub mod option {
-    pub enum Option<T> { Some(T), None }
-}
 "#,
         );
     }
diff --git a/crates/ide/src/diagnostics/missing_unsafe.rs b/crates/ide_diagnostics/src/handlers/missing_unsafe.rs
index 5c47e8d0a..7acd9228a 100644
--- a/crates/ide/src/diagnostics/missing_unsafe.rs
+++ b/crates/ide_diagnostics/src/handlers/missing_unsafe.rs
@@ -1,9 +1,9 @@
-use crate::diagnostics::{Diagnostic, DiagnosticsContext};
+use crate::{Diagnostic, DiagnosticsContext};
 
 // Diagnostic: missing-unsafe
 //
 // This diagnostic is triggered if an operation marked as `unsafe` is used outside of an `unsafe` function or block.
-pub(super) fn missing_unsafe(ctx: &DiagnosticsContext<'_>, d: &hir::MissingUnsafe) -> Diagnostic {
+pub(crate) fn missing_unsafe(ctx: &DiagnosticsContext<'_>, d: &hir::MissingUnsafe) -> Diagnostic {
     Diagnostic::new(
         "missing-unsafe",
         "this operation is unsafe and requires an unsafe function or block",
@@ -13,7 +13,7 @@ pub(super) fn missing_unsafe(ctx: &DiagnosticsContext<'_>, d: &hir::MissingUnsaf
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::check_diagnostics;
+    use crate::tests::check_diagnostics;
 
     #[test]
     fn missing_unsafe_diagnostic_with_raw_ptr() {
@@ -23,7 +23,7 @@ fn main() {
     let x = &5 as *const usize;
     unsafe { let y = *x; }
     let z = *x;
-}         //^^ this operation is unsafe and requires an unsafe function or block
+}         //^^ error: this operation is unsafe and requires an unsafe function or block
 "#,
         )
     }
@@ -48,9 +48,9 @@ unsafe fn unsafe_fn() {
 
 fn main() {
     unsafe_fn();
-  //^^^^^^^^^^^ this operation is unsafe and requires an unsafe function or block
+  //^^^^^^^^^^^ error: this operation is unsafe and requires an unsafe function or block
     HasUnsafe.unsafe_fn();
-  //^^^^^^^^^^^^^^^^^^^^^ this operation is unsafe and requires an unsafe function or block
+  //^^^^^^^^^^^^^^^^^^^^^ error: this operation is unsafe and requires an unsafe function or block
     unsafe {
         unsafe_fn();
         HasUnsafe.unsafe_fn();
@@ -72,7 +72,7 @@ static mut STATIC_MUT: Ty = Ty { a: 0 };
 
 fn main() {
     let x = STATIC_MUT.a;
-          //^^^^^^^^^^ this operation is unsafe and requires an unsafe function or block
+          //^^^^^^^^^^ error: this operation is unsafe and requires an unsafe function or block
     unsafe {
         let x = STATIC_MUT.a;
     }
@@ -93,7 +93,7 @@ extern "rust-intrinsic" {
 fn main() {
     let _ = bitreverse(12);
     let _ = floorf32(12.0);
-          //^^^^^^^^^^^^^^ this operation is unsafe and requires an unsafe function or block
+          //^^^^^^^^^^^^^^ error: this operation is unsafe and requires an unsafe function or block
 }
 "#,
         );
diff --git a/crates/ide/src/diagnostics/no_such_field.rs b/crates/ide_diagnostics/src/handlers/no_such_field.rs
index edc63c246..92e8867f4 100644
--- a/crates/ide/src/diagnostics/no_such_field.rs
+++ b/crates/ide_diagnostics/src/handlers/no_such_field.rs
@@ -6,15 +6,12 @@ use syntax::{
 };
 use text_edit::TextEdit;
 
-use crate::{
-    diagnostics::{fix, Diagnostic, DiagnosticsContext},
-    Assist,
-};
+use crate::{fix, Assist, Diagnostic, DiagnosticsContext};
 
 // Diagnostic: no-such-field
 //
 // This diagnostic is triggered if created structure does not have field provided in record.
-pub(super) fn no_such_field(ctx: &DiagnosticsContext<'_>, d: &hir::NoSuchField) -> Diagnostic {
+pub(crate) fn no_such_field(ctx: &DiagnosticsContext<'_>, d: &hir::NoSuchField) -> Diagnostic {
     Diagnostic::new(
         "no-such-field",
         "no such field",
@@ -112,7 +109,7 @@ fn missing_record_expr_field_fixes(
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::{check_diagnostics, check_fix};
+    use crate::tests::{check_diagnostics, check_fix};
 
     #[test]
     fn no_such_field_diagnostics() {
@@ -122,11 +119,11 @@ struct S { foo: i32, bar: () }
 impl S {
     fn new() -> S {
         S {
-      //^ Missing structure fields:
+      //^ 💡 error: missing structure fields:
       //|    - bar
             foo: 92,
             baz: 62,
-          //^^^^^^^ no such field
+          //^^^^^^^ 💡 error: no such field
         }
     }
 }
diff --git a/crates/ide/src/diagnostics/remove_this_semicolon.rs b/crates/ide_diagnostics/src/handlers/remove_this_semicolon.rs
index 814cb0f8c..4e639f214 100644
--- a/crates/ide/src/diagnostics/remove_this_semicolon.rs
+++ b/crates/ide_diagnostics/src/handlers/remove_this_semicolon.rs
@@ -3,15 +3,12 @@ use ide_db::source_change::SourceChange;
 use syntax::{ast, AstNode};
 use text_edit::TextEdit;
 
-use crate::{
-    diagnostics::{fix, Diagnostic, DiagnosticsContext},
-    Assist,
-};
+use crate::{fix, Assist, Diagnostic, DiagnosticsContext};
 
 // Diagnostic: remove-this-semicolon
 //
 // This diagnostic is triggered when there's an erroneous `;` at the end of the block.
-pub(super) fn remove_this_semicolon(
+pub(crate) fn remove_this_semicolon(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::RemoveThisSemicolon,
 ) -> Diagnostic {
@@ -45,14 +42,14 @@ fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::RemoveThisSemicolon) -> Option<V
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::{check_diagnostics, check_fix};
+    use crate::tests::{check_diagnostics, check_fix};
 
     #[test]
     fn missing_semicolon() {
         check_diagnostics(
             r#"
 fn test() -> i32 { 123; }
-                 //^^^ remove this semicolon
+                 //^^^ 💡 error: remove this semicolon
 "#,
         );
     }
diff --git a/crates/ide/src/diagnostics/replace_filter_map_next_with_find_map.rs b/crates/ide_diagnostics/src/handlers/replace_filter_map_next_with_find_map.rs
index f3b011495..839ceac03 100644
--- a/crates/ide/src/diagnostics/replace_filter_map_next_with_find_map.rs
+++ b/crates/ide_diagnostics/src/handlers/replace_filter_map_next_with_find_map.rs
@@ -6,15 +6,12 @@ use syntax::{
 };
 use text_edit::TextEdit;
 
-use crate::{
-    diagnostics::{fix, Diagnostic, DiagnosticsContext},
-    Assist, Severity,
-};
+use crate::{fix, Assist, Diagnostic, DiagnosticsContext, Severity};
 
 // Diagnostic: replace-filter-map-next-with-find-map
 //
 // This diagnostic is triggered when `.filter_map(..).next()` is used, rather than the more concise `.find_map(..)`.
-pub(super) fn replace_filter_map_next_with_find_map(
+pub(crate) fn replace_filter_map_next_with_find_map(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::ReplaceFilterMapNextWithFindMap,
 ) -> Diagnostic {
@@ -58,44 +55,16 @@ fn fixes(
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::check_fix;
-
-    // Register the required standard library types to make the tests work
-    #[track_caller]
-    fn check_diagnostics(ra_fixture: &str) {
-        let prefix = r#"
-//- /main.rs crate:main deps:core
-use core::iter::Iterator;
-use core::option::Option::{self, Some, None};
-"#;
-        let suffix = r#"
-//- /core/lib.rs crate:core
-pub mod option {
-    pub enum Option<T> { Some(T), None }
-}
-pub mod iter {
-    pub trait Iterator {
-        type Item;
-        fn filter_map<B, F>(self, f: F) -> FilterMap where F: FnMut(Self::Item) -> Option<B> { FilterMap }
-        fn next(&mut self) -> Option<Self::Item>;
-    }
-    pub struct FilterMap {}
-    impl Iterator for FilterMap {
-        type Item = i32;
-        fn next(&mut self) -> i32 { 7 }
-    }
-}
-"#;
-        crate::diagnostics::tests::check_diagnostics(&format!("{}{}{}", prefix, ra_fixture, suffix))
-    }
+    use crate::tests::{check_diagnostics, check_fix};
 
     #[test]
     fn replace_filter_map_next_with_find_map2() {
         check_diagnostics(
             r#"
-    fn foo() {
-        let m = [1, 2, 3].iter().filter_map(|x| if *x == 2 { Some (4) } else { None }).next();
-    }         //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ replace filter_map(..).next() with find_map(..)
+//- minicore: iterators
+fn foo() {
+    let m = core::iter::repeat(()).filter_map(|()| Some(92)).next();
+}         //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 💡 weak: replace filter_map(..).next() with find_map(..)
 "#,
         );
     }
@@ -104,11 +73,11 @@ pub mod iter {
     fn replace_filter_map_next_with_find_map_no_diagnostic_without_next() {
         check_diagnostics(
             r#"
+//- minicore: iterators
 fn foo() {
-    let m = [1, 2, 3]
-        .iter()
-        .filter_map(|x| if *x == 2 { Some (4) } else { None })
-        .len();
+    let m = core::iter::repeat(())
+        .filter_map(|()| Some(92))
+        .count();
 }
 "#,
         );
@@ -118,12 +87,12 @@ fn foo() {
     fn replace_filter_map_next_with_find_map_no_diagnostic_with_intervening_methods() {
         check_diagnostics(
             r#"
+//- minicore: iterators
 fn foo() {
-    let m = [1, 2, 3]
-        .iter()
-        .filter_map(|x| if *x == 2 { Some (4) } else { None })
+    let m = core::iter::repeat(())
+        .filter_map(|()| Some(92))
         .map(|x| x + 2)
-        .len();
+        .next();
 }
 "#,
         );
@@ -133,10 +102,10 @@ fn foo() {
     fn replace_filter_map_next_with_find_map_no_diagnostic_if_not_in_chain() {
         check_diagnostics(
             r#"
+//- minicore: iterators
 fn foo() {
-    let m = [1, 2, 3]
-        .iter()
-        .filter_map(|x| if *x == 2 { Some (4) } else { None });
+    let m = core::iter::repeat(())
+        .filter_map(|()| Some(92));
     let n = m.next();
 }
 "#,
@@ -147,34 +116,14 @@ fn foo() {
     fn replace_with_wind_map() {
         check_fix(
             r#"
-//- /main.rs crate:main deps:core
-use core::iter::Iterator;
-use core::option::Option::{self, Some, None};
+//- minicore: iterators
 fn foo() {
-    let m = [1, 2, 3].iter().$0filter_map(|x| if *x == 2 { Some (4) } else { None }).next();
-}
-//- /core/lib.rs crate:core
-pub mod option {
-    pub enum Option<T> { Some(T), None }
-}
-pub mod iter {
-    pub trait Iterator {
-        type Item;
-        fn filter_map<B, F>(self, f: F) -> FilterMap where F: FnMut(Self::Item) -> Option<B> { FilterMap }
-        fn next(&mut self) -> Option<Self::Item>;
-    }
-    pub struct FilterMap {}
-    impl Iterator for FilterMap {
-        type Item = i32;
-        fn next(&mut self) -> i32 { 7 }
-    }
+    let m = core::iter::repeat(()).$0filter_map(|()| Some(92)).next();
 }
 "#,
             r#"
-use core::iter::Iterator;
-use core::option::Option::{self, Some, None};
 fn foo() {
-    let m = [1, 2, 3].iter().find_map(|x| if *x == 2 { Some (4) } else { None });
+    let m = core::iter::repeat(()).find_map(|()| Some(92));
 }
 "#,
         )
diff --git a/crates/ide/src/diagnostics/unimplemented_builtin_macro.rs b/crates/ide_diagnostics/src/handlers/unimplemented_builtin_macro.rs
index 09faa3bbc..e879de75c 100644
--- a/crates/ide/src/diagnostics/unimplemented_builtin_macro.rs
+++ b/crates/ide_diagnostics/src/handlers/unimplemented_builtin_macro.rs
@@ -1,12 +1,9 @@
-use crate::{
-    diagnostics::{Diagnostic, DiagnosticsContext},
-    Severity,
-};
+use crate::{Diagnostic, DiagnosticsContext, Severity};
 
 // Diagnostic: unimplemented-builtin-macro
 //
 // This diagnostic is shown for builtin macros which are not yet implemented by rust-analyzer
-pub(super) fn unimplemented_builtin_macro(
+pub(crate) fn unimplemented_builtin_macro(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::UnimplementedBuiltinMacro,
 ) -> Diagnostic {
diff --git a/crates/ide/src/diagnostics/unlinked_file.rs b/crates/ide_diagnostics/src/handlers/unlinked_file.rs
index a5b2e3399..8e601fa48 100644
--- a/crates/ide/src/diagnostics/unlinked_file.rs
+++ b/crates/ide_diagnostics/src/handlers/unlinked_file.rs
@@ -12,37 +12,31 @@ use syntax::{
 };
 use text_edit::TextEdit;
 
-use crate::{
-    diagnostics::{fix, DiagnosticsContext},
-    Assist, Diagnostic,
-};
-
-#[derive(Debug)]
-pub(crate) struct UnlinkedFile {
-    pub(crate) file: FileId,
-}
+use crate::{fix, Assist, Diagnostic, DiagnosticsContext};
 
 // Diagnostic: unlinked-file
 //
 // This diagnostic is shown for files that are not included in any crate, or files that are part of
 // crates rust-analyzer failed to discover. The file will not have IDE features available.
-pub(super) fn unlinked_file(ctx: &DiagnosticsContext, d: &UnlinkedFile) -> Diagnostic {
+pub(crate) fn unlinked_file(ctx: &DiagnosticsContext, acc: &mut Vec<Diagnostic>, file_id: FileId) {
     // Limit diagnostic to the first few characters in the file. This matches how VS Code
     // renders it with the full span, but on other editors, and is less invasive.
-    let range = ctx.sema.db.parse(d.file).syntax_node().text_range();
+    let range = ctx.sema.db.parse(file_id).syntax_node().text_range();
     // FIXME: This is wrong if one of the first three characters is not ascii: `//Ы`.
     let range = range.intersect(TextRange::up_to(TextSize::of("..."))).unwrap_or(range);
 
-    Diagnostic::new("unlinked-file", "file not included in module tree", range)
-        .with_fixes(fixes(ctx, d))
+    acc.push(
+        Diagnostic::new("unlinked-file", "file not included in module tree", range)
+            .with_fixes(fixes(ctx, file_id)),
+    );
 }
 
-fn fixes(ctx: &DiagnosticsContext, d: &UnlinkedFile) -> Option<Vec<Assist>> {
+fn fixes(ctx: &DiagnosticsContext, file_id: FileId) -> Option<Vec<Assist>> {
     // If there's an existing module that could add `mod` or `pub mod` items to include the unlinked file,
     // suggest that as a fix.
 
-    let source_root = ctx.sema.db.source_root(ctx.sema.db.file_source_root(d.file));
-    let our_path = source_root.path_for_file(&d.file)?;
+    let source_root = ctx.sema.db.source_root(ctx.sema.db.file_source_root(file_id));
+    let our_path = source_root.path_for_file(&file_id)?;
     let module_name = our_path.name_and_extension()?.0;
 
     // Candidates to look for:
@@ -71,7 +65,7 @@ fn fixes(ctx: &DiagnosticsContext, d: &UnlinkedFile) -> Option<Vec<Assist>> {
                     }
 
                     if module.origin.file_id() == Some(*parent_id) {
-                        return make_fixes(ctx.sema.db, *parent_id, module_name, d.file);
+                        return make_fixes(ctx.sema.db, *parent_id, module_name, file_id);
                     }
                 }
             }
@@ -164,7 +158,7 @@ fn make_fixes(
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::{check_diagnostics, check_fix, check_fixes, check_no_fix};
+    use crate::tests::{check_diagnostics, check_fix, check_fixes, check_no_fix};
 
     #[test]
     fn unlinked_file_prepend_first_item() {
diff --git a/crates/ide/src/diagnostics/unresolved_extern_crate.rs b/crates/ide_diagnostics/src/handlers/unresolved_extern_crate.rs
index 2ea79c2ee..74e4a69c6 100644
--- a/crates/ide/src/diagnostics/unresolved_extern_crate.rs
+++ b/crates/ide_diagnostics/src/handlers/unresolved_extern_crate.rs
@@ -1,9 +1,9 @@
-use crate::diagnostics::{Diagnostic, DiagnosticsContext};
+use crate::{Diagnostic, DiagnosticsContext};
 
 // Diagnostic: unresolved-extern-crate
 //
 // This diagnostic is triggered if rust-analyzer is unable to discover referred extern crate.
-pub(super) fn unresolved_extern_crate(
+pub(crate) fn unresolved_extern_crate(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::UnresolvedExternCrate,
 ) -> Diagnostic {
@@ -16,7 +16,7 @@ pub(super) fn unresolved_extern_crate(
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::check_diagnostics;
+    use crate::tests::check_diagnostics;
 
     #[test]
     fn unresolved_extern_crate() {
@@ -25,7 +25,7 @@ mod tests {
 //- /main.rs crate:main deps:core
 extern crate core;
   extern crate doesnotexist;
-//^^^^^^^^^^^^^^^^^^^^^^^^^^ unresolved extern crate
+//^^^^^^^^^^^^^^^^^^^^^^^^^^ error: unresolved extern crate
 //- /lib.rs crate:core
 "#,
         );
@@ -38,7 +38,7 @@ extern crate core;
             r#"
 //- /lib.rs
   extern crate doesnotexist;
-//^^^^^^^^^^^^^^^^^^^^^^^^^^ unresolved extern crate
+//^^^^^^^^^^^^^^^^^^^^^^^^^^ error: unresolved extern crate
 // Should not error.
 extern crate self as foo;
 struct Foo;
diff --git a/crates/ide/src/diagnostics/unresolved_import.rs b/crates/ide_diagnostics/src/handlers/unresolved_import.rs
index 1cbf96ba1..e52a88459 100644
--- a/crates/ide/src/diagnostics/unresolved_import.rs
+++ b/crates/ide_diagnostics/src/handlers/unresolved_import.rs
@@ -1,10 +1,10 @@
-use crate::diagnostics::{Diagnostic, DiagnosticsContext};
+use crate::{Diagnostic, DiagnosticsContext};
 
 // Diagnostic: unresolved-import
 //
 // This diagnostic is triggered if rust-analyzer is unable to resolve a path in
 // a `use` declaration.
-pub(super) fn unresolved_import(
+pub(crate) fn unresolved_import(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::UnresolvedImport,
 ) -> Diagnostic {
@@ -22,7 +22,7 @@ pub(super) fn unresolved_import(
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::check_diagnostics;
+    use crate::tests::check_diagnostics;
 
     #[test]
     fn unresolved_import() {
@@ -30,7 +30,7 @@ mod tests {
             r#"
 use does_exist;
 use does_not_exist;
-  //^^^^^^^^^^^^^^ unresolved import
+  //^^^^^^^^^^^^^^ error: unresolved import
 
 mod does_exist {}
 "#,
@@ -43,18 +43,18 @@ mod does_exist {}
         check_diagnostics(
             r#"
 use does_exist::{Exists, DoesntExist};
-                       //^^^^^^^^^^^ unresolved import
+                       //^^^^^^^^^^^ error: unresolved import
 
 use {does_not_exist::*, does_exist};
-   //^^^^^^^^^^^^^^^^^ unresolved import
+   //^^^^^^^^^^^^^^^^^ error: unresolved import
 
 use does_not_exist::{
     a,
-  //^ unresolved import
+  //^ error: unresolved import
     b,
-  //^ unresolved import
+  //^ error: unresolved import
     c,
-  //^ unresolved import
+  //^ error: unresolved import
 };
 
 mod does_exist {
@@ -71,18 +71,18 @@ mod does_exist {
 //- /main.rs crate:main
 mod a {
     extern crate doesnotexist;
-  //^^^^^^^^^^^^^^^^^^^^^^^^^^ unresolved extern crate
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^ error: unresolved extern crate
 
     // Should not error, since we already errored for the missing crate.
     use doesnotexist::{self, bla, *};
 
     use crate::doesnotexist;
-      //^^^^^^^^^^^^^^^^^^^ unresolved import
+      //^^^^^^^^^^^^^^^^^^^ error: unresolved import
 }
 
 mod m {
     use super::doesnotexist;
-      //^^^^^^^^^^^^^^^^^^^ unresolved import
+      //^^^^^^^^^^^^^^^^^^^ error: unresolved import
 }
 "#,
         );
diff --git a/crates/ide/src/diagnostics/unresolved_macro_call.rs b/crates/ide_diagnostics/src/handlers/unresolved_macro_call.rs
index 15b6a2730..f0f7725db 100644
--- a/crates/ide/src/diagnostics/unresolved_macro_call.rs
+++ b/crates/ide_diagnostics/src/handlers/unresolved_macro_call.rs
@@ -1,13 +1,13 @@
 use hir::{db::AstDatabase, InFile};
 use syntax::{AstNode, SyntaxNodePtr};
 
-use crate::diagnostics::{Diagnostic, DiagnosticsContext};
+use crate::{Diagnostic, DiagnosticsContext};
 
 // Diagnostic: unresolved-macro-call
 //
 // This diagnostic is triggered if rust-analyzer is unable to resolve the path
 // to a macro in a macro invocation.
-pub(super) fn unresolved_macro_call(
+pub(crate) fn unresolved_macro_call(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::UnresolvedMacroCall,
 ) -> Diagnostic {
@@ -32,7 +32,7 @@ pub(super) fn unresolved_macro_call(
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::check_diagnostics;
+    use crate::tests::check_diagnostics;
 
     #[test]
     fn unresolved_macro_diag() {
@@ -40,7 +40,7 @@ mod tests {
             r#"
 fn f() {
     m!();
-} //^ unresolved macro `m!`
+} //^ error: unresolved macro `m!`
 
 "#,
         );
@@ -51,7 +51,7 @@ fn f() {
         check_diagnostics(
             r#"
 foo::bar!(92);
-   //^^^ unresolved macro `foo::bar!`
+   //^^^ error: unresolved macro `foo::bar!`
 "#,
         );
     }
@@ -63,7 +63,7 @@ foo::bar!(92);
 macro_rules! m { () => {} }
 
 m!(); m2!();
-    //^^ unresolved macro `self::m2!`
+    //^^ error: unresolved macro `self::m2!`
 "#,
         );
     }
@@ -77,7 +77,7 @@ mod mac {
 macro_rules! m { () => {} } }
 
 self::m!(); self::m2!();
-                //^^ unresolved macro `self::m2!`
+                //^^ error: unresolved macro `self::m2!`
 "#,
         );
     }
diff --git a/crates/ide/src/diagnostics/unresolved_module.rs b/crates/ide_diagnostics/src/handlers/unresolved_module.rs
index 977b46414..61fc43604 100644
--- a/crates/ide/src/diagnostics/unresolved_module.rs
+++ b/crates/ide_diagnostics/src/handlers/unresolved_module.rs
@@ -1,14 +1,13 @@
 use hir::db::AstDatabase;
-use ide_assists::Assist;
-use ide_db::{base_db::AnchoredPathBuf, source_change::FileSystemEdit};
+use ide_db::{assists::Assist, base_db::AnchoredPathBuf, source_change::FileSystemEdit};
 use syntax::AstNode;
 
-use crate::diagnostics::{fix, Diagnostic, DiagnosticsContext};
+use crate::{fix, Diagnostic, DiagnosticsContext};
 
 // Diagnostic: unresolved-module
 //
 // This diagnostic is triggered if rust-analyzer is unable to discover referred module.
-pub(super) fn unresolved_module(
+pub(crate) fn unresolved_module(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::UnresolvedModule,
 ) -> Diagnostic {
@@ -42,7 +41,7 @@ fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::UnresolvedModule) -> Option<Vec<
 mod tests {
     use expect_test::expect;
 
-    use crate::diagnostics::tests::{check_diagnostics, check_expect};
+    use crate::tests::{check_diagnostics, check_expect};
 
     #[test]
     fn unresolved_module() {
@@ -51,7 +50,7 @@ mod tests {
 //- /lib.rs
 mod foo;
   mod bar;
-//^^^^^^^^ unresolved module
+//^^^^^^^^ 💡 error: unresolved module
 mod baz {}
 //- /foo.rs
 "#,
diff --git a/crates/ide/src/diagnostics/unresolved_proc_macro.rs b/crates/ide_diagnostics/src/handlers/unresolved_proc_macro.rs
index 3dc6ab451..fde1d1323 100644
--- a/crates/ide/src/diagnostics/unresolved_proc_macro.rs
+++ b/crates/ide_diagnostics/src/handlers/unresolved_proc_macro.rs
@@ -1,7 +1,4 @@
-use crate::{
-    diagnostics::{Diagnostic, DiagnosticsContext},
-    Severity,
-};
+use crate::{Diagnostic, DiagnosticsContext, Severity};
 
 // Diagnostic: unresolved-proc-macro
 //
@@ -12,7 +9,7 @@ use crate::{
 // If you are seeing a lot of "proc macro not expanded" warnings, you can add this option to the
 // `rust-analyzer.diagnostics.disabled` list to prevent them from showing. Alternatively you can
 // enable support for procedural macros (see `rust-analyzer.procMacro.enable`).
-pub(super) fn unresolved_proc_macro(
+pub(crate) fn unresolved_proc_macro(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::UnresolvedProcMacro,
 ) -> Diagnostic {
diff --git a/crates/ide_diagnostics/src/handlers/useless_braces.rs b/crates/ide_diagnostics/src/handlers/useless_braces.rs
new file mode 100644
index 000000000..8b9330e04
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/useless_braces.rs
@@ -0,0 +1,148 @@
+use ide_db::{base_db::FileId, source_change::SourceChange};
+use itertools::Itertools;
+use syntax::{ast, AstNode, SyntaxNode, TextRange};
+use text_edit::TextEdit;
+
+use crate::{fix, Diagnostic, Severity};
+
+// Diagnostic: unnecessary-braces
+//
+// Diagnostic for unnecessary braces in `use` items.
+pub(crate) fn useless_braces(
+    acc: &mut Vec<Diagnostic>,
+    file_id: FileId,
+    node: &SyntaxNode,
+) -> Option<()> {
+    let use_tree_list = ast::UseTreeList::cast(node.clone())?;
+    if let Some((single_use_tree,)) = use_tree_list.use_trees().collect_tuple() {
+        // If there is a comment inside the bracketed `use`,
+        // assume it is a commented out module path and don't show diagnostic.
+        if use_tree_list.has_inner_comment() {
+            return Some(());
+        }
+
+        let use_range = use_tree_list.syntax().text_range();
+        let edit = remove_braces(&single_use_tree).unwrap_or_else(|| {
+            let to_replace = single_use_tree.syntax().text().to_string();
+            let mut edit_builder = TextEdit::builder();
+            edit_builder.delete(use_range);
+            edit_builder.insert(use_range.start(), to_replace);
+            edit_builder.finish()
+        });
+
+        acc.push(
+            Diagnostic::new(
+                "unnecessary-braces",
+                "Unnecessary braces in use statement".to_string(),
+                use_range,
+            )
+            .severity(Severity::WeakWarning)
+            .with_fixes(Some(vec![fix(
+                "remove_braces",
+                "Remove unnecessary braces",
+                SourceChange::from_text_edit(file_id, edit),
+                use_range,
+            )])),
+        );
+    }
+
+    Some(())
+}
+
+fn remove_braces(single_use_tree: &ast::UseTree) -> Option<TextEdit> {
+    let use_tree_list_node = single_use_tree.syntax().parent()?;
+    if single_use_tree.path()?.segment()?.self_token().is_some() {
+        let start = use_tree_list_node.prev_sibling_or_token()?.text_range().start();
+        let end = use_tree_list_node.text_range().end();
+        return Some(TextEdit::delete(TextRange::new(start, end)));
+    }
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_diagnostics, check_fix};
+
+    #[test]
+    fn test_check_unnecessary_braces_in_use_statement() {
+        check_diagnostics(
+            r#"
+use a;
+use a::{c, d::e};
+
+mod a {
+    mod c {}
+    mod d {
+        mod e {}
+    }
+}
+"#,
+        );
+        check_diagnostics(
+            r#"
+use a;
+use a::{
+    c,
+    // d::e
+};
+
+mod a {
+    mod c {}
+    mod d {
+        mod e {}
+    }
+}
+"#,
+        );
+        check_fix(
+            r#"
+mod b {}
+use {$0b};
+"#,
+            r#"
+mod b {}
+use b;
+"#,
+        );
+        check_fix(
+            r#"
+mod b {}
+use {b$0};
+"#,
+            r#"
+mod b {}
+use b;
+"#,
+        );
+        check_fix(
+            r#"
+mod a { mod c {} }
+use a::{c$0};
+"#,
+            r#"
+mod a { mod c {} }
+use a::c;
+"#,
+        );
+        check_fix(
+            r#"
+mod a {}
+use a::{self$0};
+"#,
+            r#"
+mod a {}
+use a;
+"#,
+        );
+        check_fix(
+            r#"
+mod a { mod c {} mod d { mod e {} } }
+use a::{c, d::{e$0}};
+"#,
+            r#"
+mod a { mod c {} mod d { mod e {} } }
+use a::{c, d::e};
+"#,
+        );
+    }
+}
diff --git a/crates/ide_diagnostics/src/lib.rs b/crates/ide_diagnostics/src/lib.rs
new file mode 100644
index 000000000..6ad1b4373
--- /dev/null
+++ b/crates/ide_diagnostics/src/lib.rs
@@ -0,0 +1,374 @@
+//! Diagnostics rendering and fixits.
+//!
+//! Most of the diagnostics originate from the dark depth of the compiler, and
+//! are originally expressed in term of IR. When we emit the diagnostic, we are
+//! usually not in the position to decide how to best "render" it in terms of
+//! user-authored source code. We are especially not in the position to offer
+//! fixits, as the compiler completely lacks the infrastructure to edit the
+//! source code.
+//!
+//! Instead, we "bubble up" raw, structured diagnostics until the `hir` crate,
+//! where we "cook" them so that each diagnostic is formulated in terms of `hir`
+//! types. Well, at least that's the aspiration, the "cooking" is somewhat
+//! ad-hoc at the moment. Anyways, we get a bunch of ide-friendly diagnostic
+//! structs from hir, and we want to render them to unified serializable
+//! representation (span, level, message) here. If we can, we also provide
+//! fixits. By the way, that's why we want to keep diagnostics structured
+//! internally -- so that we have all the info to make fixes.
+//!
+//! We have one "handler" module per diagnostic code. Such a module contains
+//! rendering, optional fixes and tests. It's OK if some low-level compiler
+//! functionality ends up being tested via a diagnostic.
+//!
+//! There are also a couple of ad-hoc diagnostics implemented directly here, we
+//! don't yet have a great pattern for how to do them properly.
+
+mod handlers {
+    pub(crate) mod break_outside_of_loop;
+    pub(crate) mod inactive_code;
+    pub(crate) mod incorrect_case;
+    pub(crate) mod macro_error;
+    pub(crate) mod mismatched_arg_count;
+    pub(crate) mod missing_fields;
+    pub(crate) mod missing_match_arms;
+    pub(crate) mod missing_ok_or_some_in_tail_expr;
+    pub(crate) mod missing_unsafe;
+    pub(crate) mod no_such_field;
+    pub(crate) mod remove_this_semicolon;
+    pub(crate) mod replace_filter_map_next_with_find_map;
+    pub(crate) mod unimplemented_builtin_macro;
+    pub(crate) mod unresolved_extern_crate;
+    pub(crate) mod unresolved_import;
+    pub(crate) mod unresolved_macro_call;
+    pub(crate) mod unresolved_module;
+    pub(crate) mod unresolved_proc_macro;
+
+    // The handlers bellow are unusual, the implement the diagnostics as well.
+    pub(crate) mod field_shorthand;
+    pub(crate) mod useless_braces;
+    pub(crate) mod unlinked_file;
+}
+
+use hir::{diagnostics::AnyDiagnostic, Semantics};
+use ide_db::{
+    assists::{Assist, AssistId, AssistKind, AssistResolveStrategy},
+    base_db::{FileId, SourceDatabase},
+    label::Label,
+    source_change::SourceChange,
+    RootDatabase,
+};
+use rustc_hash::FxHashSet;
+use syntax::{ast::AstNode, TextRange};
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub struct DiagnosticCode(pub &'static str);
+
+impl DiagnosticCode {
+    pub fn as_str(&self) -> &str {
+        self.0
+    }
+}
+
+#[derive(Debug)]
+pub struct Diagnostic {
+    pub code: DiagnosticCode,
+    pub message: String,
+    pub range: TextRange,
+    pub severity: Severity,
+    pub unused: bool,
+    pub experimental: bool,
+    pub fixes: Option<Vec<Assist>>,
+}
+
+impl Diagnostic {
+    fn new(code: &'static str, message: impl Into<String>, range: TextRange) -> Diagnostic {
+        let message = message.into();
+        Diagnostic {
+            code: DiagnosticCode(code),
+            message,
+            range,
+            severity: Severity::Error,
+            unused: false,
+            experimental: false,
+            fixes: None,
+        }
+    }
+
+    fn experimental(mut self) -> Diagnostic {
+        self.experimental = true;
+        self
+    }
+
+    fn severity(mut self, severity: Severity) -> Diagnostic {
+        self.severity = severity;
+        self
+    }
+
+    fn with_fixes(mut self, fixes: Option<Vec<Assist>>) -> Diagnostic {
+        self.fixes = fixes;
+        self
+    }
+
+    fn with_unused(mut self, unused: bool) -> Diagnostic {
+        self.unused = unused;
+        self
+    }
+}
+
+#[derive(Debug, Copy, Clone)]
+pub enum Severity {
+    Error,
+    // We don't actually emit this one yet, but we should at some point.
+    // Warning,
+    WeakWarning,
+}
+
+#[derive(Default, Debug, Clone)]
+pub struct DiagnosticsConfig {
+    pub disable_experimental: bool,
+    pub disabled: FxHashSet<String>,
+}
+
+struct DiagnosticsContext<'a> {
+    config: &'a DiagnosticsConfig,
+    sema: Semantics<'a, RootDatabase>,
+    resolve: &'a AssistResolveStrategy,
+}
+
+pub fn diagnostics(
+    db: &RootDatabase,
+    config: &DiagnosticsConfig,
+    resolve: &AssistResolveStrategy,
+    file_id: FileId,
+) -> Vec<Diagnostic> {
+    let _p = profile::span("diagnostics");
+    let sema = Semantics::new(db);
+    let parse = db.parse(file_id);
+    let mut res = Vec::new();
+
+    // [#34344] Only take first 128 errors to prevent slowing down editor/ide, the number 128 is chosen arbitrarily.
+    res.extend(
+        parse.errors().iter().take(128).map(|err| {
+            Diagnostic::new("syntax-error", format!("Syntax Error: {}", err), err.range())
+        }),
+    );
+
+    for node in parse.tree().syntax().descendants() {
+        handlers::useless_braces::useless_braces(&mut res, file_id, &node);
+        handlers::field_shorthand::field_shorthand(&mut res, file_id, &node);
+    }
+
+    let module = sema.to_module_def(file_id);
+
+    let ctx = DiagnosticsContext { config, sema, resolve };
+    if module.is_none() {
+        handlers::unlinked_file::unlinked_file(&ctx, &mut res, file_id);
+    }
+
+    let mut diags = Vec::new();
+    if let Some(m) = module {
+        m.diagnostics(db, &mut diags)
+    }
+
+    for diag in diags {
+        #[rustfmt::skip]
+        let d = match diag {
+            AnyDiagnostic::BreakOutsideOfLoop(d) => handlers::break_outside_of_loop::break_outside_of_loop(&ctx, &d),
+            AnyDiagnostic::IncorrectCase(d) => handlers::incorrect_case::incorrect_case(&ctx, &d),
+            AnyDiagnostic::MacroError(d) => handlers::macro_error::macro_error(&ctx, &d),
+            AnyDiagnostic::MismatchedArgCount(d) => handlers::mismatched_arg_count::mismatched_arg_count(&ctx, &d),
+            AnyDiagnostic::MissingFields(d) => handlers::missing_fields::missing_fields(&ctx, &d),
+            AnyDiagnostic::MissingMatchArms(d) => handlers::missing_match_arms::missing_match_arms(&ctx, &d),
+            AnyDiagnostic::MissingOkOrSomeInTailExpr(d) => handlers::missing_ok_or_some_in_tail_expr::missing_ok_or_some_in_tail_expr(&ctx, &d),
+            AnyDiagnostic::MissingUnsafe(d) => handlers::missing_unsafe::missing_unsafe(&ctx, &d),
+            AnyDiagnostic::NoSuchField(d) => handlers::no_such_field::no_such_field(&ctx, &d),
+            AnyDiagnostic::RemoveThisSemicolon(d) => handlers::remove_this_semicolon::remove_this_semicolon(&ctx, &d),
+            AnyDiagnostic::ReplaceFilterMapNextWithFindMap(d) => handlers::replace_filter_map_next_with_find_map::replace_filter_map_next_with_find_map(&ctx, &d),
+            AnyDiagnostic::UnimplementedBuiltinMacro(d) => handlers::unimplemented_builtin_macro::unimplemented_builtin_macro(&ctx, &d),
+            AnyDiagnostic::UnresolvedExternCrate(d) => handlers::unresolved_extern_crate::unresolved_extern_crate(&ctx, &d),
+            AnyDiagnostic::UnresolvedImport(d) => handlers::unresolved_import::unresolved_import(&ctx, &d),
+            AnyDiagnostic::UnresolvedMacroCall(d) => handlers::unresolved_macro_call::unresolved_macro_call(&ctx, &d),
+            AnyDiagnostic::UnresolvedModule(d) => handlers::unresolved_module::unresolved_module(&ctx, &d),
+            AnyDiagnostic::UnresolvedProcMacro(d) => handlers::unresolved_proc_macro::unresolved_proc_macro(&ctx, &d),
+
+            AnyDiagnostic::InactiveCode(d) => match handlers::inactive_code::inactive_code(&ctx, &d) {
+                Some(it) => it,
+                None => continue,
+            }
+        };
+        res.push(d)
+    }
+
+    res.retain(|d| {
+        !ctx.config.disabled.contains(d.code.as_str())
+            && !(ctx.config.disable_experimental && d.experimental)
+    });
+
+    res
+}
+
+fn fix(id: &'static str, label: &str, source_change: SourceChange, target: TextRange) -> Assist {
+    let mut res = unresolved_fix(id, label, target);
+    res.source_change = Some(source_change);
+    res
+}
+
+fn unresolved_fix(id: &'static str, label: &str, target: TextRange) -> Assist {
+    assert!(!id.contains(' '));
+    Assist {
+        id: AssistId(id, AssistKind::QuickFix),
+        label: Label::new(label),
+        group: None,
+        target,
+        source_change: None,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use expect_test::Expect;
+    use ide_db::{
+        assists::AssistResolveStrategy,
+        base_db::{fixture::WithFixture, SourceDatabaseExt},
+        RootDatabase,
+    };
+    use stdx::trim_indent;
+    use test_utils::{assert_eq_text, extract_annotations};
+
+    use crate::{DiagnosticsConfig, Severity};
+
+    /// Takes a multi-file input fixture with annotated cursor positions,
+    /// and checks that:
+    ///  * a diagnostic is produced
+    ///  * the first diagnostic fix trigger range touches the input cursor position
+    ///  * that the contents of the file containing the cursor match `after` after the diagnostic fix is applied
+    #[track_caller]
+    pub(crate) fn check_fix(ra_fixture_before: &str, ra_fixture_after: &str) {
+        check_nth_fix(0, ra_fixture_before, ra_fixture_after);
+    }
+    /// Takes a multi-file input fixture with annotated cursor positions,
+    /// and checks that:
+    ///  * a diagnostic is produced
+    ///  * every diagnostic fixes trigger range touches the input cursor position
+    ///  * that the contents of the file containing the cursor match `after` after each diagnostic fix is applied
+    pub(crate) fn check_fixes(ra_fixture_before: &str, ra_fixtures_after: Vec<&str>) {
+        for (i, ra_fixture_after) in ra_fixtures_after.iter().enumerate() {
+            check_nth_fix(i, ra_fixture_before, ra_fixture_after)
+        }
+    }
+
+    #[track_caller]
+    fn check_nth_fix(nth: usize, ra_fixture_before: &str, ra_fixture_after: &str) {
+        let after = trim_indent(ra_fixture_after);
+
+        let (db, file_position) = RootDatabase::with_position(ra_fixture_before);
+        let diagnostic = super::diagnostics(
+            &db,
+            &DiagnosticsConfig::default(),
+            &AssistResolveStrategy::All,
+            file_position.file_id,
+        )
+        .pop()
+        .expect("no diagnostics");
+        let fix = &diagnostic.fixes.expect("diagnostic misses fixes")[nth];
+        let actual = {
+            let source_change = fix.source_change.as_ref().unwrap();
+            let file_id = *source_change.source_file_edits.keys().next().unwrap();
+            let mut actual = db.file_text(file_id).to_string();
+
+            for edit in source_change.source_file_edits.values() {
+                edit.apply(&mut actual);
+            }
+            actual
+        };
+
+        assert_eq_text!(&after, &actual);
+        assert!(
+            fix.target.contains_inclusive(file_position.offset),
+            "diagnostic fix range {:?} does not touch cursor position {:?}",
+            fix.target,
+            file_position.offset
+        );
+    }
+
+    /// Checks that there's a diagnostic *without* fix at `$0`.
+    pub(crate) fn check_no_fix(ra_fixture: &str) {
+        let (db, file_position) = RootDatabase::with_position(ra_fixture);
+        let diagnostic = super::diagnostics(
+            &db,
+            &DiagnosticsConfig::default(),
+            &AssistResolveStrategy::All,
+            file_position.file_id,
+        )
+        .pop()
+        .unwrap();
+        assert!(diagnostic.fixes.is_none(), "got a fix when none was expected: {:?}", diagnostic);
+    }
+
+    pub(crate) fn check_expect(ra_fixture: &str, expect: Expect) {
+        let (db, file_id) = RootDatabase::with_single_file(ra_fixture);
+        let diagnostics = super::diagnostics(
+            &db,
+            &DiagnosticsConfig::default(),
+            &AssistResolveStrategy::All,
+            file_id,
+        );
+        expect.assert_debug_eq(&diagnostics)
+    }
+
+    #[track_caller]
+    pub(crate) fn check_diagnostics(ra_fixture: &str) {
+        let mut config = DiagnosticsConfig::default();
+        config.disabled.insert("inactive-code".to_string());
+        check_diagnostics_with_config(config, ra_fixture)
+    }
+
+    #[track_caller]
+    pub(crate) fn check_diagnostics_with_config(config: DiagnosticsConfig, ra_fixture: &str) {
+        let (db, files) = RootDatabase::with_many_files(ra_fixture);
+        for file_id in files {
+            let diagnostics =
+                super::diagnostics(&db, &config, &AssistResolveStrategy::All, file_id);
+
+            let expected = extract_annotations(&*db.file_text(file_id));
+            let mut actual = diagnostics
+                .into_iter()
+                .map(|d| {
+                    let mut annotation = String::new();
+                    if let Some(fixes) = &d.fixes {
+                        assert!(!fixes.is_empty());
+                        annotation.push_str("💡 ")
+                    }
+                    annotation.push_str(match d.severity {
+                        Severity::Error => "error",
+                        Severity::WeakWarning => "weak",
+                    });
+                    annotation.push_str(": ");
+                    annotation.push_str(&d.message);
+                    (d.range, annotation)
+                })
+                .collect::<Vec<_>>();
+            actual.sort_by_key(|(range, _)| range.start());
+            assert_eq!(expected, actual);
+        }
+    }
+
+    #[test]
+    fn test_disabled_diagnostics() {
+        let mut config = DiagnosticsConfig::default();
+        config.disabled.insert("unresolved-module".into());
+
+        let (db, file_id) = RootDatabase::with_single_file(r#"mod foo;"#);
+
+        let diagnostics = super::diagnostics(&db, &config, &AssistResolveStrategy::All, file_id);
+        assert!(diagnostics.is_empty());
+
+        let diagnostics = super::diagnostics(
+            &db,
+            &DiagnosticsConfig::default(),
+            &AssistResolveStrategy::All,
+            file_id,
+        );
+        assert!(!diagnostics.is_empty());
+    }
+}
diff --git a/crates/mbe/src/expander/matcher.rs b/crates/mbe/src/expander/matcher.rs
index c2a9a38c9..b4f2fe9a4 100644
--- a/crates/mbe/src/expander/matcher.rs
+++ b/crates/mbe/src/expander/matcher.rs
@@ -804,33 +804,17 @@ impl<'a> TtIter<'a> {
         };
 
         match (punct.char, second, third) {
-            ('.', '.', Some('.'))
-            | ('.', '.', Some('='))
-            | ('<', '<', Some('='))
-            | ('>', '>', Some('=')) => {
+            ('.', '.', Some('.' | '=')) | ('<', '<', Some('=')) | ('>', '>', Some('=')) => {
                 let tt2 = self.next().unwrap().clone();
                 let tt3 = self.next().unwrap().clone();
                 Ok(tt::Subtree { delimiter: None, token_trees: vec![tt, tt2, tt3] }.into())
             }
-            ('-', '=', _)
-            | ('-', '>', _)
+            ('-' | '!' | '*' | '/' | '&' | '%' | '^' | '+' | '<' | '=' | '>' | '|', '=', _)
+            | ('-' | '=' | '>', '>', _)
             | (':', ':', _)
-            | ('!', '=', _)
             | ('.', '.', _)
-            | ('*', '=', _)
-            | ('/', '=', _)
             | ('&', '&', _)
-            | ('&', '=', _)
-            | ('%', '=', _)
-            | ('^', '=', _)
-            | ('+', '=', _)
             | ('<', '<', _)
-            | ('<', '=', _)
-            | ('=', '=', _)
-            | ('=', '>', _)
-            | ('>', '=', _)
-            | ('>', '>', _)
-            | ('|', '=', _)
             | ('|', '|', _) => {
                 let tt2 = self.next().unwrap().clone();
                 Ok(tt::Subtree { delimiter: None, token_trees: vec![tt, tt2] }.into())
diff --git a/crates/parser/src/grammar/params.rs b/crates/parser/src/grammar/params.rs
index 01ee26a53..5a78675fb 100644
--- a/crates/parser/src/grammar/params.rs
+++ b/crates/parser/src/grammar/params.rs
@@ -184,8 +184,7 @@ fn opt_self_param(p: &mut Parser, m: Marker) -> Result<(), Marker> {
         if !matches!(
             (p.current(), la1, la2, la3),
             (T![&], T![self], _, _)
-                | (T![&], T![mut], T![self], _)
-                | (T![&], LIFETIME_IDENT, T![self], _)
+                | (T![&], T![mut] | LIFETIME_IDENT, T![self], _)
                 | (T![&], LIFETIME_IDENT, T![mut], T![self])
         ) {
             return Err(m);
diff --git a/crates/proc_macro_api/src/version.rs b/crates/proc_macro_api/src/version.rs
index 28a4ac086..434decc7e 100644
--- a/crates/proc_macro_api/src/version.rs
+++ b/crates/proc_macro_api/src/version.rs
@@ -28,23 +28,23 @@ pub fn read_dylib_info(dylib_path: &Path) -> io::Result<RustCInfo> {
 
     let ver_str = read_version(dylib_path)?;
     let mut items = ver_str.split_whitespace();
-    let tag = items.next().ok_or(err!("version format error"))?;
+    let tag = items.next().ok_or_else(|| err!("version format error"))?;
     if tag != "rustc" {
         return Err(err!("version format error (No rustc tag)"));
     }
 
-    let version_part = items.next().ok_or(err!("no version string"))?;
+    let version_part = items.next().ok_or_else(|| err!("no version string"))?;
     let mut version_parts = version_part.split('-');
-    let version = version_parts.next().ok_or(err!("no version"))?;
+    let version = version_parts.next().ok_or_else(|| err!("no version"))?;
     let channel = version_parts.next().unwrap_or_default().to_string();
 
-    let commit = items.next().ok_or(err!("no commit info"))?;
+    let commit = items.next().ok_or_else(|| err!("no commit info"))?;
     // remove (
     if commit.len() == 0 {
         return Err(err!("commit format error"));
     }
     let commit = commit[1..].to_string();
-    let date = items.next().ok_or(err!("no date info"))?;
+    let date = items.next().ok_or_else(|| err!("no date info"))?;
     // remove )
     if date.len() == 0 {
         return Err(err!("date format error"));
diff --git a/crates/project_model/src/build_data.rs b/crates/project_model/src/build_data.rs
index 53cb4bae7..45bbb08dc 100644
--- a/crates/project_model/src/build_data.rs
+++ b/crates/project_model/src/build_data.rs
@@ -187,7 +187,7 @@ impl WorkspaceBuildData {
                 let mut deserializer = serde_json::Deserializer::from_str(line);
                 deserializer.disable_recursion_limit();
                 let message = Message::deserialize(&mut deserializer)
-                    .unwrap_or(Message::TextLine(line.to_string()));
+                    .unwrap_or_else(|_| Message::TextLine(line.to_string()));
 
                 match message {
                     Message::BuildScriptExecuted(BuildScript {
@@ -229,7 +229,7 @@ impl WorkspaceBuildData {
                     Message::CompilerArtifact(message) => {
                         progress(format!("metadata {}", message.target.name));
 
-                        if message.target.kind.contains(&"proc-macro".to_string()) {
+                        if message.target.kind.iter().any(|k| k == "proc-macro") {
                             let package_id = message.package_id;
                             // Skip rmeta file
                             if let Some(filename) =
diff --git a/crates/project_model/src/cargo_workspace.rs b/crates/project_model/src/cargo_workspace.rs
index ac079f83e..0935ea967 100644
--- a/crates/project_model/src/cargo_workspace.rs
+++ b/crates/project_model/src/cargo_workspace.rs
@@ -1,5 +1,6 @@
 //! See [`CargoWorkspace`].
 
+use std::iter;
 use std::path::PathBuf;
 use std::{convert::TryInto, ops, process::Command, sync::Arc};
 
@@ -12,6 +13,7 @@ use rustc_hash::FxHashMap;
 use serde::Deserialize;
 use serde_json::from_value;
 
+use crate::CfgOverrides;
 use crate::{build_data::BuildDataConfig, utf8_stdout};
 
 /// [`CargoWorkspace`] represents the logical structure of, well, a Cargo
@@ -76,6 +78,21 @@ pub struct CargoConfig {
 
     /// rustc private crate source
     pub rustc_source: Option<RustcSource>,
+
+    /// crates to disable `#[cfg(test)]` on
+    pub unset_test_crates: Vec<String>,
+}
+
+impl CargoConfig {
+    pub fn cfg_overrides(&self) -> CfgOverrides {
+        self.unset_test_crates
+            .iter()
+            .cloned()
+            .zip(iter::repeat_with(|| {
+                cfg::CfgDiff::new(Vec::new(), vec![cfg::CfgAtom::Flag("test".into())]).unwrap()
+            }))
+            .collect()
+    }
 }
 
 pub type Package = Idx<PackageData>;
diff --git a/crates/project_model/src/lib.rs b/crates/project_model/src/lib.rs
index 8c6cf94c2..1d408dff2 100644
--- a/crates/project_model/src/lib.rs
+++ b/crates/project_model/src/lib.rs
@@ -41,7 +41,7 @@ pub use crate::{
     },
     project_json::{ProjectJson, ProjectJsonData},
     sysroot::Sysroot,
-    workspace::{PackageRoot, ProjectWorkspace},
+    workspace::{CfgOverrides, PackageRoot, ProjectWorkspace},
 };
 
 pub use proc_macro_api::ProcMacroClient;
diff --git a/crates/project_model/src/sysroot.rs b/crates/project_model/src/sysroot.rs
index a22f79c15..006263da8 100644
--- a/crates/project_model/src/sysroot.rs
+++ b/crates/project_model/src/sysroot.rs
@@ -68,8 +68,9 @@ impl Sysroot {
     pub fn load(sysroot_src_dir: &AbsPath) -> Result<Sysroot> {
         let mut sysroot = Sysroot { crates: Arena::default() };
 
-        for name in SYSROOT_CRATES.trim().lines() {
-            let root = [format!("{}/src/lib.rs", name), format!("lib{}/lib.rs", name)]
+        for path in SYSROOT_CRATES.trim().lines() {
+            let name = path.split('/').last().unwrap();
+            let root = [format!("{}/src/lib.rs", path), format!("lib{}/lib.rs", path)]
                 .iter()
                 .map(|it| sysroot_src_dir.join(it))
                 .find(|it| it.exists());
@@ -191,9 +192,8 @@ panic_abort
 panic_unwind
 proc_macro
 profiler_builtins
-rtstartup
 std
-stdarch
+stdarch/crates/std_detect
 term
 test
 unwind";
@@ -204,9 +204,8 @@ core
 panic_abort
 panic_unwind
 profiler_builtins
-rtstartup
 proc_macro
-stdarch
+std_detect
 term
 test
 unwind";
diff --git a/crates/project_model/src/workspace.rs b/crates/project_model/src/workspace.rs
index ef0f3c9e4..d8217f714 100644
--- a/crates/project_model/src/workspace.rs
+++ b/crates/project_model/src/workspace.rs
@@ -7,7 +7,7 @@ use std::{collections::VecDeque, fmt, fs, path::Path, process::Command};
 use anyhow::{format_err, Context, Result};
 use base_db::{CrateDisplayName, CrateGraph, CrateId, CrateName, Edition, Env, FileId, ProcMacro};
 use cargo_workspace::DepKind;
-use cfg::CfgOptions;
+use cfg::{CfgDiff, CfgOptions};
 use paths::{AbsPath, AbsPathBuf};
 use proc_macro_api::ProcMacroClient;
 use rustc_hash::{FxHashMap, FxHashSet};
@@ -22,6 +22,8 @@ use crate::{
     Sysroot, TargetKind,
 };
 
+pub type CfgOverrides = FxHashMap<String, CfgDiff>;
+
 /// `PackageRoot` describes a package root folder.
 /// Which may be an external dependency, or a member of
 /// the current workspace.
@@ -46,6 +48,7 @@ pub enum ProjectWorkspace {
         /// FIXME: make this a per-crate map, as, eg, build.rs might have a
         /// different target.
         rustc_cfg: Vec<CfgFlag>,
+        cfg_overrides: CfgOverrides,
     },
     /// Project workspace was manually specified using a `rust-project.json` file.
     Json { project: ProjectJson, sysroot: Option<Sysroot>, rustc_cfg: Vec<CfgFlag> },
@@ -67,7 +70,7 @@ impl fmt::Debug for ProjectWorkspace {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // Make sure this isn't too verbose.
         match self {
-            ProjectWorkspace::Cargo { cargo, sysroot, rustc, rustc_cfg } => f
+            ProjectWorkspace::Cargo { cargo, sysroot, rustc, rustc_cfg, cfg_overrides } => f
                 .debug_struct("Cargo")
                 .field("root", &cargo.workspace_root().file_name())
                 .field("n_packages", &cargo.packages().len())
@@ -77,6 +80,7 @@ impl fmt::Debug for ProjectWorkspace {
                     &rustc.as_ref().map_or(0, |rc| rc.packages().len()),
                 )
                 .field("n_rustc_cfg", &rustc_cfg.len())
+                .field("n_cfg_overrides", &cfg_overrides.len())
                 .finish(),
             ProjectWorkspace::Json { project, sysroot, rustc_cfg } => {
                 let mut debug_struct = f.debug_struct("Json");
@@ -164,7 +168,9 @@ impl ProjectWorkspace {
                 };
 
                 let rustc_cfg = rustc_cfg::get(Some(&cargo_toml), config.target.as_deref());
-                ProjectWorkspace::Cargo { cargo, sysroot, rustc, rustc_cfg }
+
+                let cfg_overrides = config.cfg_overrides();
+                ProjectWorkspace::Cargo { cargo, sysroot, rustc, rustc_cfg, cfg_overrides }
             }
         };
 
@@ -213,43 +219,45 @@ impl ProjectWorkspace {
                     })
                 }))
                 .collect::<Vec<_>>(),
-            ProjectWorkspace::Cargo { cargo, sysroot, rustc, rustc_cfg: _ } => cargo
-                .packages()
-                .map(|pkg| {
-                    let is_member = cargo[pkg].is_member;
-                    let pkg_root = cargo[pkg].root().to_path_buf();
-
-                    let mut include = vec![pkg_root.clone()];
-                    include.extend(
-                        build_data
-                            .and_then(|it| it.get(cargo.workspace_root()))
-                            .and_then(|map| map.get(&cargo[pkg].id))
-                            .and_then(|it| it.out_dir.clone()),
-                    );
+            ProjectWorkspace::Cargo { cargo, sysroot, rustc, rustc_cfg: _, cfg_overrides: _ } => {
+                cargo
+                    .packages()
+                    .map(|pkg| {
+                        let is_member = cargo[pkg].is_member;
+                        let pkg_root = cargo[pkg].root().to_path_buf();
+
+                        let mut include = vec![pkg_root.clone()];
+                        include.extend(
+                            build_data
+                                .and_then(|it| it.get(cargo.workspace_root()))
+                                .and_then(|map| map.get(&cargo[pkg].id))
+                                .and_then(|it| it.out_dir.clone()),
+                        );
 
-                    let mut exclude = vec![pkg_root.join(".git")];
-                    if is_member {
-                        exclude.push(pkg_root.join("target"));
-                    } else {
-                        exclude.push(pkg_root.join("tests"));
-                        exclude.push(pkg_root.join("examples"));
-                        exclude.push(pkg_root.join("benches"));
-                    }
-                    PackageRoot { is_member, include, exclude }
-                })
-                .chain(sysroot.crates().map(|krate| PackageRoot {
-                    is_member: false,
-                    include: vec![sysroot[krate].root_dir().to_path_buf()],
-                    exclude: Vec::new(),
-                }))
-                .chain(rustc.into_iter().flat_map(|rustc| {
-                    rustc.packages().map(move |krate| PackageRoot {
+                        let mut exclude = vec![pkg_root.join(".git")];
+                        if is_member {
+                            exclude.push(pkg_root.join("target"));
+                        } else {
+                            exclude.push(pkg_root.join("tests"));
+                            exclude.push(pkg_root.join("examples"));
+                            exclude.push(pkg_root.join("benches"));
+                        }
+                        PackageRoot { is_member, include, exclude }
+                    })
+                    .chain(sysroot.crates().map(|krate| PackageRoot {
                         is_member: false,
-                        include: vec![rustc[krate].root().to_path_buf()],
+                        include: vec![sysroot[krate].root_dir().to_path_buf()],
                         exclude: Vec::new(),
-                    })
-                }))
-                .collect(),
+                    }))
+                    .chain(rustc.into_iter().flat_map(|rustc| {
+                        rustc.packages().map(move |krate| PackageRoot {
+                            is_member: false,
+                            include: vec![rustc[krate].root().to_path_buf()],
+                            exclude: Vec::new(),
+                        })
+                    }))
+                    .collect()
+            }
             ProjectWorkspace::DetachedFiles { files, sysroot, .. } => files
                 .into_iter()
                 .map(|detached_file| PackageRoot {
@@ -299,16 +307,22 @@ impl ProjectWorkspace {
                 project,
                 sysroot,
             ),
-            ProjectWorkspace::Cargo { cargo, sysroot, rustc, rustc_cfg } => cargo_to_crate_graph(
-                rustc_cfg.clone(),
-                &proc_macro_loader,
-                load,
-                cargo,
-                build_data.and_then(|it| it.get(cargo.workspace_root())),
-                sysroot,
-                rustc,
-                rustc.as_ref().zip(build_data).and_then(|(it, map)| map.get(it.workspace_root())),
-            ),
+            ProjectWorkspace::Cargo { cargo, sysroot, rustc, rustc_cfg, cfg_overrides } => {
+                cargo_to_crate_graph(
+                    rustc_cfg.clone(),
+                    cfg_overrides,
+                    &proc_macro_loader,
+                    load,
+                    cargo,
+                    build_data.and_then(|it| it.get(cargo.workspace_root())),
+                    sysroot,
+                    rustc,
+                    rustc
+                        .as_ref()
+                        .zip(build_data)
+                        .and_then(|(it, map)| map.get(it.workspace_root())),
+                )
+            }
             ProjectWorkspace::DetachedFiles { files, sysroot, rustc_cfg } => {
                 detached_files_to_crate_graph(rustc_cfg.clone(), load, files, sysroot)
             }
@@ -398,6 +412,7 @@ fn project_json_to_crate_graph(
 
 fn cargo_to_crate_graph(
     rustc_cfg: Vec<CfgFlag>,
+    override_cfg: &CfgOverrides,
     proc_macro_loader: &dyn Fn(&Path) -> Vec<ProcMacro>,
     load: &mut dyn FnMut(&AbsPath) -> Option<FileId>,
     cargo: &CargoWorkspace,
@@ -425,6 +440,21 @@ fn cargo_to_crate_graph(
     let mut has_private = false;
     // Next, create crates for each package, target pair
     for pkg in cargo.packages() {
+        let mut cfg_options = &cfg_options;
+        let mut replaced_cfg_options;
+        if let Some(overrides) = override_cfg.get(&cargo[pkg].name) {
+            // FIXME: this is sort of a hack to deal with #![cfg(not(test))] vanishing such as seen
+            // in ed25519_dalek (#7243), and libcore (#9203) (although you only hit that one while
+            // working on rust-lang/rust as that's the only time it appears outside sysroot).
+            //
+            // A more ideal solution might be to reanalyze crates based on where the cursor is and
+            // figure out the set of cfgs that would have to apply to make it active.
+
+            replaced_cfg_options = cfg_options.clone();
+            replaced_cfg_options.apply_diff(overrides.clone());
+            cfg_options = &replaced_cfg_options;
+        };
+
         has_private |= cargo[pkg].metadata.rustc_private;
         let mut lib_tgt = None;
         for &tgt in cargo[pkg].targets.iter() {
diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs
index fa72a9bfb..3aeca8839 100644
--- a/crates/rust-analyzer/src/config.rs
+++ b/crates/rust-analyzer/src/config.rs
@@ -44,6 +44,9 @@ config_data! {
         assist_importPrefix: ImportPrefixDef               = "\"plain\"",
         /// Group inserted imports by the [following order](https://rust-analyzer.github.io/manual.html#auto-import). Groups are separated by newlines.
         assist_importGroup: bool                           = "true",
+        /// Whether to allow import insertion to merge new imports into single path glob imports like `use std::fmt::*;`.
+        assist_allowMergingIntoGlobImports: bool           = "true",
+
         /// Show function name and docs in parameter hints.
         callInfo_full: bool                                = "true",
 
@@ -52,6 +55,8 @@ config_data! {
         cargo_autoreload: bool           = "true",
         /// Activate all available features (`--all-features`).
         cargo_allFeatures: bool          = "false",
+        /// Unsets `#[cfg(test)]` for the specified crates.
+        cargo_unsetTest: Vec<String>   = "[\"core\"]",
         /// List of features to activate.
         cargo_features: Vec<String>      = "[]",
         /// Run build scripts (`build.rs`) for more precise code analysis.
@@ -596,8 +601,10 @@ impl Config {
             target: self.data.cargo_target.clone(),
             rustc_source,
             no_sysroot: self.data.cargo_noSysroot,
+            unset_test_crates: self.data.cargo_unsetTest.clone(),
         }
     }
+
     pub fn rustfmt(&self) -> RustfmtConfig {
         match &self.data.rustfmt_overrideCommand {
             Some(args) if !args.is_empty() => {
@@ -676,6 +683,7 @@ impl Config {
                 ImportPrefixDef::BySelf => PrefixKind::BySelf,
             },
             group: self.data.assist_importGroup,
+            skip_glob_imports: !self.data.assist_allowMergingIntoGlobImports,
         }
     }
     pub fn completion(&self) -> CompletionConfig {
@@ -806,7 +814,9 @@ enum ImportGranularityDef {
 #[serde(rename_all = "snake_case")]
 enum ImportPrefixDef {
     Plain,
+    #[serde(alias = "self")]
     BySelf,
+    #[serde(alias = "crate")]
     ByCrate,
 }
 
@@ -993,13 +1003,13 @@ fn field_props(field: &str, ty: &str, doc: &[&str], default: &str) -> serde_json
             "type": "string",
             "enum": [
                 "plain",
-                "by_self",
-                "by_crate"
+                "self",
+                "crate"
             ],
             "enumDescriptions": [
                 "Insert import paths relative to the current module, using up to one `super` prefix if the parent module contains the requested item.",
-                "Prefix all import paths with `self` if they don't begin with `self`, `super`, `crate` or a crate name.",
-                "Force import paths to be absolute by always starting them with `crate` or the crate name they refer to."
+                "Insert import paths relative to the current module, using up to one `super` prefix if the parent module contains the requested item. Prefixes `self` in front of the path if it starts with a module.",
+                "Force import paths to be absolute by always starting them with `crate` or the extern crate name they come from."
             ],
         },
         "Vec<ManifestOrProjectJson>" => set! {
@@ -1069,8 +1079,8 @@ mod tests {
         let package_json_path = project_root().join("editors/code/package.json");
         let mut package_json = fs::read_to_string(&package_json_path).unwrap();
 
-        let start_marker = "                \"$generated-start\": false,\n";
-        let end_marker = "                \"$generated-end\": false\n";
+        let start_marker = "                \"$generated-start\": {},\n";
+        let end_marker = "                \"$generated-end\": {}\n";
 
         let start = package_json.find(start_marker).unwrap() + start_marker.len();
         let end = package_json.find(end_marker).unwrap();
diff --git a/crates/rust-analyzer/src/diagnostics/test_data/handles_macro_location.txt b/crates/rust-analyzer/src/diagnostics/test_data/handles_macro_location.txt
index d5ab03576..a7f936a70 100644
--- a/crates/rust-analyzer/src/diagnostics/test_data/handles_macro_location.txt
+++ b/crates/rust-analyzer/src/diagnostics/test_data/handles_macro_location.txt
@@ -54,7 +54,7 @@
             source: Some(
                 "rustc",
             ),
-            message: "can\'t compare `{integer}` with `&str`\nthe trait `std::cmp::PartialEq<&str>` is not implemented for `{integer}`",
+            message: "can't compare `{integer}` with `&str`\nthe trait `std::cmp::PartialEq<&str>` is not implemented for `{integer}`",
             related_information: None,
             tags: None,
             data: None,
diff --git a/crates/rust-analyzer/src/diagnostics/test_data/rustc_incompatible_type_for_trait.txt b/crates/rust-analyzer/src/diagnostics/test_data/rustc_incompatible_type_for_trait.txt
index ada540ea6..afc562a0e 100644
--- a/crates/rust-analyzer/src/diagnostics/test_data/rustc_incompatible_type_for_trait.txt
+++ b/crates/rust-analyzer/src/diagnostics/test_data/rustc_incompatible_type_for_trait.txt
@@ -54,7 +54,7 @@
             source: Some(
                 "rustc",
             ),
-            message: "method `next` has an incompatible type for trait\nexpected type `fn(&mut ty::list_iter::ListIterator<\'list, M>) -> std::option::Option<&ty::Ref<M>>`\n   found type `fn(&ty::list_iter::ListIterator<\'list, M>) -> std::option::Option<&\'list ty::Ref<M>>`",
+            message: "method `next` has an incompatible type for trait\nexpected type `fn(&mut ty::list_iter::ListIterator<'list, M>) -> std::option::Option<&ty::Ref<M>>`\n   found type `fn(&ty::list_iter::ListIterator<'list, M>) -> std::option::Option<&'list ty::Ref<M>>`",
             related_information: None,
             tags: None,
             data: None,
diff --git a/crates/rust-analyzer/src/integrated_benchmarks.rs b/crates/rust-analyzer/src/integrated_benchmarks.rs
index 8ddeb59f7..f8afc930a 100644
--- a/crates/rust-analyzer/src/integrated_benchmarks.rs
+++ b/crates/rust-analyzer/src/integrated_benchmarks.rs
@@ -143,6 +143,7 @@ fn integrated_completion_benchmark() {
                 prefix_kind: hir::PrefixKind::ByCrate,
                 enforce_granularity: true,
                 group: true,
+                skip_glob_imports: true,
             },
         };
         let position =
@@ -178,6 +179,7 @@ fn integrated_completion_benchmark() {
                 prefix_kind: hir::PrefixKind::ByCrate,
                 enforce_granularity: true,
                 group: true,
+                skip_glob_imports: true,
             },
         };
         let position =
diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
index e53cd3c7b..310d8c6d2 100644
--- a/crates/rust-analyzer/src/to_proto.rs
+++ b/crates/rust-analyzer/src/to_proto.rs
@@ -1187,6 +1187,7 @@ mod tests {
                         prefix_kind: PrefixKind::Plain,
                         enforce_granularity: true,
                         group: true,
+                        skip_glob_imports: true,
                     },
                 },
                 ide_db::base_db::FilePosition { file_id, offset },
diff --git a/crates/rust-analyzer/tests/slow-tests/support.rs b/crates/rust-analyzer/tests/slow-tests/support.rs
index e22c295f9..260a504e7 100644
--- a/crates/rust-analyzer/tests/slow-tests/support.rs
+++ b/crates/rust-analyzer/tests/slow-tests/support.rs
@@ -75,7 +75,9 @@ impl<'a> Project<'a> {
             profile::init_from(crate::PROFILE);
         });
 
-        for entry in Fixture::parse(self.fixture) {
+        let (mini_core, fixtures) = Fixture::parse(self.fixture);
+        assert!(mini_core.is_none());
+        for entry in fixtures {
             let path = tmp_dir.path().join(&entry.path['/'.len_utf8()..]);
             fs::create_dir_all(path.parent().unwrap()).unwrap();
             fs::write(path.as_path(), entry.text.as_bytes()).unwrap();
diff --git a/crates/syntax/src/ast/node_ext.rs b/crates/syntax/src/ast/node_ext.rs
index 3d27d2c1a..e33e5bb03 100644
--- a/crates/syntax/src/ast/node_ext.rs
+++ b/crates/syntax/src/ast/node_ext.rs
@@ -8,7 +8,7 @@ use parser::SyntaxKind;
 use rowan::{GreenNodeData, GreenTokenData};
 
 use crate::{
-    ast::{self, support, AstNode, AstToken, AttrsOwner, NameOwner, SyntaxNode},
+    ast::{self, support, AstChildren, AstNode, AstToken, AttrsOwner, NameOwner, SyntaxNode},
     NodeOrToken, SmolStr, SyntaxElement, SyntaxToken, TokenText, T,
 };
 
@@ -45,6 +45,12 @@ fn text_of_first_token(node: &SyntaxNode) -> TokenText<'_> {
     }
 }
 
+impl ast::BlockExpr {
+    pub fn items(&self) -> AstChildren<ast::Item> {
+        support::children(self.syntax())
+    }
+}
+
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum Macro {
     MacroRules(ast::MacroRules),
@@ -281,6 +287,15 @@ impl ast::Path {
         successors(self.qualifier(), |p| p.qualifier())
     }
 }
+
+impl ast::Use {
+    pub fn is_simple_glob(&self) -> bool {
+        self.use_tree()
+            .map(|use_tree| use_tree.use_tree_list().is_none() && use_tree.star_token().is_some())
+            .unwrap_or(false)
+    }
+}
+
 impl ast::UseTree {
     pub fn is_simple_path(&self) -> bool {
         self.use_tree_list().is_none() && self.star_token().is_none()
@@ -325,6 +340,15 @@ impl ast::Impl {
         let second = types.next();
         (first, second)
     }
+
+    pub fn for_trait_name_ref(name_ref: &ast::NameRef) -> Option<ast::Impl> {
+        let this = name_ref.syntax().ancestors().find_map(ast::Impl::cast)?;
+        if this.trait_()?.syntax().text_range().start() == name_ref.syntax().text_range().start() {
+            Some(this)
+        } else {
+            None
+        }
+    }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -666,6 +690,14 @@ impl ast::LifetimeParam {
     }
 }
 
+impl ast::Module {
+    /// Returns the parent ast::Module, this is different than the semantic parent in that this only
+    /// considers parent declarations in the AST
+    pub fn parent(&self) -> Option<ast::Module> {
+        self.syntax().ancestors().nth(2).and_then(ast::Module::cast)
+    }
+}
+
 impl ast::RangePat {
     pub fn start(&self) -> Option<ast::Pat> {
         self.syntax()
diff --git a/crates/syntax/test_data/lexer/err/0001_unclosed_char_at_eof.txt b/crates/syntax/test_data/lexer/err/0001_unclosed_char_at_eof.txt
index 4d5ad74df..135f49552 100644
--- a/crates/syntax/test_data/lexer/err/0001_unclosed_char_at_eof.txt
+++ b/crates/syntax/test_data/lexer/err/0001_unclosed_char_at_eof.txt
@@ -1,2 +1,2 @@
-CHAR 1 "\'"
-> error0..1 token("\'") msg(Missing trailing `'` symbol to terminate the character literal)
+CHAR 1 "'"
+> error0..1 token("'") msg(Missing trailing `'` symbol to terminate the character literal)
diff --git a/crates/syntax/test_data/lexer/err/0002_unclosed_char_with_ferris.txt b/crates/syntax/test_data/lexer/err/0002_unclosed_char_with_ferris.txt
index eafdb3c7c..cc3933d95 100644
--- a/crates/syntax/test_data/lexer/err/0002_unclosed_char_with_ferris.txt
+++ b/crates/syntax/test_data/lexer/err/0002_unclosed_char_with_ferris.txt
@@ -1,2 +1,2 @@
-CHAR 5 "\'🦀"
-> error0..5 token("\'🦀") msg(Missing trailing `'` symbol to terminate the character literal)
+CHAR 5 "'🦀"
+> error0..5 token("'🦀") msg(Missing trailing `'` symbol to terminate the character literal)
diff --git a/crates/syntax/test_data/lexer/err/0003_unclosed_char_with_ascii_escape.txt b/crates/syntax/test_data/lexer/err/0003_unclosed_char_with_ascii_escape.txt
index cc2b4866a..21d990e6f 100644
--- a/crates/syntax/test_data/lexer/err/0003_unclosed_char_with_ascii_escape.txt
+++ b/crates/syntax/test_data/lexer/err/0003_unclosed_char_with_ascii_escape.txt
@@ -1,2 +1,2 @@
-CHAR 5 "\'\\x7f"
-> error0..5 token("\'\\x7f") msg(Missing trailing `'` symbol to terminate the character literal)
+CHAR 5 "'\\x7f"
+> error0..5 token("'\\x7f") msg(Missing trailing `'` symbol to terminate the character literal)
diff --git a/crates/syntax/test_data/lexer/err/0004_unclosed_char_with_unicode_escape.txt b/crates/syntax/test_data/lexer/err/0004_unclosed_char_with_unicode_escape.txt
index a6d422cb3..055dba64c 100644
--- a/crates/syntax/test_data/lexer/err/0004_unclosed_char_with_unicode_escape.txt
+++ b/crates/syntax/test_data/lexer/err/0004_unclosed_char_with_unicode_escape.txt
@@ -1,2 +1,2 @@
-CHAR 9 "\'\\u{20AA}"
-> error0..9 token("\'\\u{20AA}") msg(Missing trailing `'` symbol to terminate the character literal)
+CHAR 9 "'\\u{20AA}"
+> error0..9 token("'\\u{20AA}") msg(Missing trailing `'` symbol to terminate the character literal)
diff --git a/crates/syntax/test_data/lexer/err/0005_unclosed_char_with_space.txt b/crates/syntax/test_data/lexer/err/0005_unclosed_char_with_space.txt
index 47e7baa70..9ee5e93fa 100644
--- a/crates/syntax/test_data/lexer/err/0005_unclosed_char_with_space.txt
+++ b/crates/syntax/test_data/lexer/err/0005_unclosed_char_with_space.txt
@@ -1,2 +1,2 @@
-CHAR 2 "\' "
-> error0..2 token("\' ") msg(Missing trailing `'` symbol to terminate the character literal)
+CHAR 2 "' "
+> error0..2 token("' ") msg(Missing trailing `'` symbol to terminate the character literal)
diff --git a/crates/syntax/test_data/lexer/err/0006_unclosed_char_with_slash.txt b/crates/syntax/test_data/lexer/err/0006_unclosed_char_with_slash.txt
index 511029d80..dc3a596f6 100644
--- a/crates/syntax/test_data/lexer/err/0006_unclosed_char_with_slash.txt
+++ b/crates/syntax/test_data/lexer/err/0006_unclosed_char_with_slash.txt
@@ -1,2 +1,2 @@
-CHAR 2 "\'\\"
-> error0..2 token("\'\\") msg(Missing trailing `'` symbol to terminate the character literal)
+CHAR 2 "'\\"
+> error0..2 token("'\\") msg(Missing trailing `'` symbol to terminate the character literal)
diff --git a/crates/syntax/test_data/lexer/err/0007_unclosed_char_with_slash_n.txt b/crates/syntax/test_data/lexer/err/0007_unclosed_char_with_slash_n.txt
index d2ba5742c..e46edea98 100644
--- a/crates/syntax/test_data/lexer/err/0007_unclosed_char_with_slash_n.txt
+++ b/crates/syntax/test_data/lexer/err/0007_unclosed_char_with_slash_n.txt
@@ -1,2 +1,2 @@
-CHAR 3 "\'\\n"
-> error0..3 token("\'\\n") msg(Missing trailing `'` symbol to terminate the character literal)
+CHAR 3 "'\\n"
+> error0..3 token("'\\n") msg(Missing trailing `'` symbol to terminate the character literal)
diff --git a/crates/syntax/test_data/lexer/err/0008_unclosed_char_with_slash_single_quote.txt b/crates/syntax/test_data/lexer/err/0008_unclosed_char_with_slash_single_quote.txt
index ae9a7f0e2..8ad1e913a 100644
--- a/crates/syntax/test_data/lexer/err/0008_unclosed_char_with_slash_single_quote.txt
+++ b/crates/syntax/test_data/lexer/err/0008_unclosed_char_with_slash_single_quote.txt
@@ -1,2 +1,2 @@
-CHAR 3 "\'\\\'"
-> error0..3 token("\'\\\'") msg(Missing trailing `'` symbol to terminate the character literal)
+CHAR 3 "'\\'"
+> error0..3 token("'\\'") msg(Missing trailing `'` symbol to terminate the character literal)
diff --git a/crates/syntax/test_data/lexer/err/0009_unclosed_byte_at_eof.txt b/crates/syntax/test_data/lexer/err/0009_unclosed_byte_at_eof.txt
index ff1504592..9d30c7466 100644
--- a/crates/syntax/test_data/lexer/err/0009_unclosed_byte_at_eof.txt
+++ b/crates/syntax/test_data/lexer/err/0009_unclosed_byte_at_eof.txt
@@ -1,2 +1,2 @@
-BYTE 2 "b\'"
-> error0..2 token("b\'") msg(Missing trailing `'` symbol to terminate the byte literal)
+BYTE 2 "b'"
+> error0..2 token("b'") msg(Missing trailing `'` symbol to terminate the byte literal)
diff --git a/crates/syntax/test_data/lexer/err/0010_unclosed_byte_with_ferris.txt b/crates/syntax/test_data/lexer/err/0010_unclosed_byte_with_ferris.txt
index 34f7bd6d4..9dbf4203e 100644
--- a/crates/syntax/test_data/lexer/err/0010_unclosed_byte_with_ferris.txt
+++ b/crates/syntax/test_data/lexer/err/0010_unclosed_byte_with_ferris.txt
@@ -1,2 +1,2 @@
-BYTE 6 "b\'🦀"
-> error0..6 token("b\'🦀") msg(Missing trailing `'` symbol to terminate the byte literal)
+BYTE 6 "b'🦀"
+> error0..6 token("b'🦀") msg(Missing trailing `'` symbol to terminate the byte literal)
diff --git a/crates/syntax/test_data/lexer/err/0011_unclosed_byte_with_ascii_escape.txt b/crates/syntax/test_data/lexer/err/0011_unclosed_byte_with_ascii_escape.txt
index c964d0f00..d5d9c2ef7 100644
--- a/crates/syntax/test_data/lexer/err/0011_unclosed_byte_with_ascii_escape.txt
+++ b/crates/syntax/test_data/lexer/err/0011_unclosed_byte_with_ascii_escape.txt
@@ -1,2 +1,2 @@
-BYTE 6 "b\'\\x7f"
-> error0..6 token("b\'\\x7f") msg(Missing trailing `'` symbol to terminate the byte literal)
+BYTE 6 "b'\\x7f"
+> error0..6 token("b'\\x7f") msg(Missing trailing `'` symbol to terminate the byte literal)
diff --git a/crates/syntax/test_data/lexer/err/0012_unclosed_byte_with_unicode_escape.txt b/crates/syntax/test_data/lexer/err/0012_unclosed_byte_with_unicode_escape.txt
index cc65fb86f..a99b9666a 100644
--- a/crates/syntax/test_data/lexer/err/0012_unclosed_byte_with_unicode_escape.txt
+++ b/crates/syntax/test_data/lexer/err/0012_unclosed_byte_with_unicode_escape.txt
@@ -1,2 +1,2 @@
-BYTE 10 "b\'\\u{20AA}"
-> error0..10 token("b\'\\u{20AA}") msg(Missing trailing `'` symbol to terminate the byte literal)
+BYTE 10 "b'\\u{20AA}"
+> error0..10 token("b'\\u{20AA}") msg(Missing trailing `'` symbol to terminate the byte literal)
diff --git a/crates/syntax/test_data/lexer/err/0013_unclosed_byte_with_space.txt b/crates/syntax/test_data/lexer/err/0013_unclosed_byte_with_space.txt
index 800834a14..8a344f712 100644
--- a/crates/syntax/test_data/lexer/err/0013_unclosed_byte_with_space.txt
+++ b/crates/syntax/test_data/lexer/err/0013_unclosed_byte_with_space.txt
@@ -1,2 +1,2 @@
-BYTE 3 "b\' "
-> error0..3 token("b\' ") msg(Missing trailing `'` symbol to terminate the byte literal)
+BYTE 3 "b' "
+> error0..3 token("b' ") msg(Missing trailing `'` symbol to terminate the byte literal)
diff --git a/crates/syntax/test_data/lexer/err/0014_unclosed_byte_with_slash.txt b/crates/syntax/test_data/lexer/err/0014_unclosed_byte_with_slash.txt
index 7b85ee646..b78a43c02 100644
--- a/crates/syntax/test_data/lexer/err/0014_unclosed_byte_with_slash.txt
+++ b/crates/syntax/test_data/lexer/err/0014_unclosed_byte_with_slash.txt
@@ -1,2 +1,2 @@
-BYTE 3 "b\'\\"
-> error0..3 token("b\'\\") msg(Missing trailing `'` symbol to terminate the byte literal)
+BYTE 3 "b'\\"
+> error0..3 token("b'\\") msg(Missing trailing `'` symbol to terminate the byte literal)
diff --git a/crates/syntax/test_data/lexer/err/0015_unclosed_byte_with_slash_n.txt b/crates/syntax/test_data/lexer/err/0015_unclosed_byte_with_slash_n.txt
index 4b9a63117..5147363ba 100644
--- a/crates/syntax/test_data/lexer/err/0015_unclosed_byte_with_slash_n.txt
+++ b/crates/syntax/test_data/lexer/err/0015_unclosed_byte_with_slash_n.txt
@@ -1,2 +1,2 @@
-BYTE 4 "b\'\\n"
-> error0..4 token("b\'\\n") msg(Missing trailing `'` symbol to terminate the byte literal)
+BYTE 4 "b'\\n"
+> error0..4 token("b'\\n") msg(Missing trailing `'` symbol to terminate the byte literal)
diff --git a/crates/syntax/test_data/lexer/err/0016_unclosed_byte_with_slash_single_quote.txt b/crates/syntax/test_data/lexer/err/0016_unclosed_byte_with_slash_single_quote.txt
index fe337f8d3..261c0894f 100644
--- a/crates/syntax/test_data/lexer/err/0016_unclosed_byte_with_slash_single_quote.txt
+++ b/crates/syntax/test_data/lexer/err/0016_unclosed_byte_with_slash_single_quote.txt
@@ -1,2 +1,2 @@
-BYTE 4 "b\'\\\'"
-> error0..4 token("b\'\\\'") msg(Missing trailing `'` symbol to terminate the byte literal)
+BYTE 4 "b'\\'"
+> error0..4 token("b'\\'") msg(Missing trailing `'` symbol to terminate the byte literal)
diff --git a/crates/syntax/test_data/lexer/err/0057_lifetime_starts_with_a_number.txt b/crates/syntax/test_data/lexer/err/0057_lifetime_starts_with_a_number.txt
index 11e0ae14a..b746404d2 100644
--- a/crates/syntax/test_data/lexer/err/0057_lifetime_starts_with_a_number.txt
+++ b/crates/syntax/test_data/lexer/err/0057_lifetime_starts_with_a_number.txt
@@ -1,6 +1,6 @@
-LIFETIME_IDENT 2 "\'1"
+LIFETIME_IDENT 2 "'1"
 WHITESPACE 1 "\n"
-LIFETIME_IDENT 10 "\'1lifetime"
+LIFETIME_IDENT 10 "'1lifetime"
 WHITESPACE 1 "\n"
-> error0..2 token("\'1") msg(Lifetime name cannot start with a number)
-> error3..13 token("\'1lifetime") msg(Lifetime name cannot start with a number)
+> error0..2 token("'1") msg(Lifetime name cannot start with a number)
+> error3..13 token("'1lifetime") msg(Lifetime name cannot start with a number)
diff --git a/crates/syntax/test_data/lexer/ok/0006_chars.txt b/crates/syntax/test_data/lexer/ok/0006_chars.txt
index 950954fbc..756477dc9 100644
--- a/crates/syntax/test_data/lexer/ok/0006_chars.txt
+++ b/crates/syntax/test_data/lexer/ok/0006_chars.txt
@@ -1,16 +1,16 @@
-CHAR 3 "\'x\'"
+CHAR 3 "'x'"
 WHITESPACE 1 " "
-CHAR 3 "\' \'"
+CHAR 3 "' '"
 WHITESPACE 1 " "
-CHAR 3 "\'0\'"
+CHAR 3 "'0'"
 WHITESPACE 1 " "
-CHAR 7 "\'hello\'"
+CHAR 7 "'hello'"
 WHITESPACE 1 " "
-CHAR 6 "\'\\x7f\'"
+CHAR 6 "'\\x7f'"
 WHITESPACE 1 " "
-CHAR 4 "\'\\n\'"
+CHAR 4 "'\\n'"
 WHITESPACE 1 " "
-CHAR 4 "\'\\\\\'"
+CHAR 4 "'\\\\'"
 WHITESPACE 1 " "
-CHAR 4 "\'\\\'\'"
+CHAR 4 "'\\''"
 WHITESPACE 1 "\n"
diff --git a/crates/syntax/test_data/lexer/ok/0007_lifetimes.txt b/crates/syntax/test_data/lexer/ok/0007_lifetimes.txt
index 4d6625c3a..32ed9ed50 100644
--- a/crates/syntax/test_data/lexer/ok/0007_lifetimes.txt
+++ b/crates/syntax/test_data/lexer/ok/0007_lifetimes.txt
@@ -1,8 +1,8 @@
-LIFETIME_IDENT 2 "\'a"
+LIFETIME_IDENT 2 "'a"
 WHITESPACE 1 " "
-LIFETIME_IDENT 4 "\'foo"
+LIFETIME_IDENT 4 "'foo"
 WHITESPACE 1 " "
-LIFETIME_IDENT 12 "\'foo_bar_baz"
+LIFETIME_IDENT 12 "'foo_bar_baz"
 WHITESPACE 1 " "
-LIFETIME_IDENT 2 "\'_"
+LIFETIME_IDENT 2 "'_"
 WHITESPACE 1 "\n"
diff --git a/crates/syntax/test_data/lexer/ok/0008_byte_strings.txt b/crates/syntax/test_data/lexer/ok/0008_byte_strings.txt
index e61ad99be..06d6bdd1f 100644
--- a/crates/syntax/test_data/lexer/ok/0008_byte_strings.txt
+++ b/crates/syntax/test_data/lexer/ok/0008_byte_strings.txt
@@ -1,22 +1,22 @@
-BYTE 3 "b\'\'"
+BYTE 3 "b''"
 WHITESPACE 1 " "
-BYTE 4 "b\'x\'"
+BYTE 4 "b'x'"
 WHITESPACE 1 " "
 BYTE_STRING 6 "b\"foo\""
 WHITESPACE 1 " "
 BYTE_STRING 4 "br\"\""
 WHITESPACE 1 "\n"
-BYTE 6 "b\'\'suf"
+BYTE 6 "b''suf"
 WHITESPACE 1 " "
 BYTE_STRING 5 "b\"\"ix"
 WHITESPACE 1 " "
 BYTE_STRING 6 "br\"\"br"
 WHITESPACE 1 "\n"
-BYTE 5 "b\'\\n\'"
+BYTE 5 "b'\\n'"
 WHITESPACE 1 " "
-BYTE 5 "b\'\\\\\'"
+BYTE 5 "b'\\\\'"
 WHITESPACE 1 " "
-BYTE 5 "b\'\\\'\'"
+BYTE 5 "b'\\''"
 WHITESPACE 1 " "
-BYTE 8 "b\'hello\'"
+BYTE 8 "b'hello'"
 WHITESPACE 1 "\n"
diff --git a/crates/syntax/test_data/parser/err/0024_many_type_parens.rast b/crates/syntax/test_data/parser/err/0024_many_type_parens.rast
index 4c4ddf5ec..be4a62940 100644
--- a/crates/syntax/test_data/parser/err/0024_many_type_parens.rast
+++ b/crates/syntax/test_data/parser/err/0024_many_type_parens.rast
@@ -43,7 +43,7 @@ [email protected]
                 [email protected] "<"
                 [email protected]
                   [email protected]
-                    [email protected] "\'a"
+                    [email protected] "'a"
                 [email protected] ">"
               [email protected] " "
               [email protected]
@@ -55,7 +55,7 @@ [email protected]
                       [email protected] "<"
                       [email protected]
                         [email protected]
-                          [email protected] "\'a"
+                          [email protected] "'a"
                       [email protected] ">"
             [email protected] ")"
       [email protected] ">"
@@ -128,7 +128,7 @@ [email protected]
                   [email protected] "<"
                   [email protected]
                     [email protected]
-                      [email protected] "\'a"
+                      [email protected] "'a"
                   [email protected] ">"
                 [email protected] " "
                 [email protected]
@@ -140,7 +140,7 @@ [email protected]
                         [email protected] "<"
                         [email protected]
                           [email protected]
-                            [email protected] "\'a"
+                            [email protected] "'a"
                         [email protected] ">"
               [email protected] ")"
       [email protected]
@@ -191,7 +191,7 @@ [email protected]
                 [email protected]
                   [email protected] "<"
                   [email protected]
-                    [email protected] "\'a"
+                    [email protected] "'a"
                   [email protected] ">"
             [email protected] " "
             [email protected]
@@ -205,7 +205,7 @@ [email protected]
                             [email protected] "Trait"
                     [email protected] "<"
                     [email protected]
-                      [email protected] "\'a"
+                      [email protected] "'a"
                   [email protected] ">"
                   [email protected]
                     [email protected] ")"
@@ -250,7 +250,7 @@ [email protected]
                               [email protected] "<"
                               [email protected]
                                 [email protected]
-                                  [email protected] "\'a"
+                                  [email protected] "'a"
                               [email protected] ">"
                             [email protected] " "
                             [email protected]
@@ -262,7 +262,7 @@ [email protected]
                                     [email protected] "<"
                                     [email protected]
                                       [email protected]
-                                        [email protected] "\'a"
+                                        [email protected] "'a"
                                     [email protected] ">"
                           [email protected] ")"
             [email protected] " "
diff --git a/crates/syntax/test_data/parser/err/0027_incomplere_where_for.rast b/crates/syntax/test_data/parser/err/0027_incomplere_where_for.rast
index c5215d6b1..b021783fc 100644
--- a/crates/syntax/test_data/parser/err/0027_incomplere_where_for.rast
+++ b/crates/syntax/test_data/parser/err/0027_incomplere_where_for.rast
@@ -17,7 +17,7 @@ [email protected]
           [email protected] "<"
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] ">"
     [email protected] "\n"
     [email protected]
diff --git a/crates/syntax/test_data/parser/err/0043_weird_blocks.rast b/crates/syntax/test_data/parser/err/0043_weird_blocks.rast
index e73bd1aea..e24f01e29 100644
--- a/crates/syntax/test_data/parser/err/0043_weird_blocks.rast
+++ b/crates/syntax/test_data/parser/err/0043_weird_blocks.rast
@@ -55,7 +55,7 @@ [email protected]
           [email protected]
             [email protected]
               [email protected]
-                [email protected] "\'label"
+                [email protected] "'label"
               [email protected] ":"
         [email protected] " "
         [email protected]
diff --git a/crates/syntax/test_data/parser/err/0044_unexpected_for_type.rast b/crates/syntax/test_data/parser/err/0044_unexpected_for_type.rast
index cc54185e5..a2460a7ec 100644
--- a/crates/syntax/test_data/parser/err/0044_unexpected_for_type.rast
+++ b/crates/syntax/test_data/parser/err/0044_unexpected_for_type.rast
@@ -13,13 +13,13 @@ [email protected]
         [email protected] "<"
         [email protected]
           [email protected]
-            [email protected] "\'a"
+            [email protected] "'a"
         [email protected] ">"
       [email protected] " "
       [email protected]
         [email protected] "&"
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
         [email protected] " "
         [email protected]
           [email protected]
@@ -42,7 +42,7 @@ [email protected]
         [email protected] "<"
         [email protected]
           [email protected]
-            [email protected] "\'a"
+            [email protected] "'a"
         [email protected] ">"
       [email protected] " "
       [email protected]
@@ -50,7 +50,7 @@ [email protected]
         [email protected]
           [email protected] "&"
           [email protected]
-            [email protected] "\'a"
+            [email protected] "'a"
           [email protected] " "
           [email protected]
             [email protected]
@@ -75,7 +75,7 @@ [email protected]
         [email protected] "<"
         [email protected]
           [email protected]
-            [email protected] "\'a"
+            [email protected] "'a"
         [email protected] ">"
       [email protected] " "
       [email protected]
@@ -102,7 +102,7 @@ [email protected]
         [email protected] "<"
         [email protected]
           [email protected]
-            [email protected] "\'a"
+            [email protected] "'a"
         [email protected] ">"
       [email protected] " "
       [email protected]
@@ -111,7 +111,7 @@ [email protected]
           [email protected] "<"
           [email protected]
             [email protected]
-              [email protected] "\'b"
+              [email protected] "'b"
           [email protected] ">"
         [email protected] " "
         [email protected]
@@ -122,7 +122,7 @@ [email protected]
               [email protected]
                 [email protected] "&"
                 [email protected]
-                  [email protected] "\'a"
+                  [email protected] "'a"
                 [email protected] " "
                 [email protected]
                   [email protected]
@@ -135,7 +135,7 @@ [email protected]
               [email protected]
                 [email protected] "&"
                 [email protected]
-                  [email protected] "\'b"
+                  [email protected] "'b"
                 [email protected] " "
                 [email protected]
                   [email protected]
@@ -169,7 +169,7 @@ [email protected]
           [email protected] "<"
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] ">"
         [email protected] " "
         [email protected]
@@ -178,7 +178,7 @@ [email protected]
             [email protected] "<"
             [email protected]
               [email protected]
-                [email protected] "\'b"
+                [email protected] "'b"
             [email protected] ">"
           [email protected] " "
           [email protected]
@@ -187,7 +187,7 @@ [email protected]
               [email protected] "<"
               [email protected]
                 [email protected]
-                  [email protected] "\'c"
+                  [email protected] "'c"
               [email protected] ">"
             [email protected] " "
             [email protected]
@@ -198,7 +198,7 @@ [email protected]
                   [email protected]
                     [email protected] "&"
                     [email protected]
-                      [email protected] "\'a"
+                      [email protected] "'a"
                     [email protected] " "
                     [email protected]
                       [email protected]
@@ -211,7 +211,7 @@ [email protected]
                   [email protected]
                     [email protected] "&"
                     [email protected]
-                      [email protected] "\'b"
+                      [email protected] "'b"
                     [email protected] " "
                     [email protected]
                       [email protected]
@@ -224,7 +224,7 @@ [email protected]
                   [email protected]
                     [email protected] "&"
                     [email protected]
-                      [email protected] "\'c"
+                      [email protected] "'c"
                     [email protected] " "
                     [email protected]
                       [email protected]
diff --git a/crates/syntax/test_data/parser/err/0046_ambiguous_trait_object.rast b/crates/syntax/test_data/parser/err/0046_ambiguous_trait_object.rast
index 7049f4734..6eaa32b96 100644
--- a/crates/syntax/test_data/parser/err/0046_ambiguous_trait_object.rast
+++ b/crates/syntax/test_data/parser/err/0046_ambiguous_trait_object.rast
@@ -8,7 +8,7 @@ [email protected]
       [email protected] "<"
       [email protected]
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
       [email protected] ">"
     [email protected] " "
     [email protected] "="
@@ -16,7 +16,7 @@ [email protected]
     [email protected]
       [email protected] "&"
       [email protected]
-        [email protected] "\'a"
+        [email protected] "'a"
       [email protected] " "
       [email protected]
         [email protected] "dyn"
@@ -104,7 +104,7 @@ [email protected]
             [email protected] " "
             [email protected]
               [email protected]
-                [email protected] "\'static"
+                [email protected] "'static"
     [email protected] ";"
   [email protected] "\n"
   [email protected]
diff --git a/crates/syntax/test_data/parser/inline/err/0002_misplaced_label_err.rast b/crates/syntax/test_data/parser/inline/err/0002_misplaced_label_err.rast
index 0adf2cd5a..97bb5059d 100644
--- a/crates/syntax/test_data/parser/inline/err/0002_misplaced_label_err.rast
+++ b/crates/syntax/test_data/parser/inline/err/0002_misplaced_label_err.rast
@@ -15,7 +15,7 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'loop"
+              [email protected] "'loop"
             [email protected] ":"
       [email protected] " "
       [email protected]
diff --git a/crates/syntax/test_data/parser/inline/ok/0003_where_pred_for.rast b/crates/syntax/test_data/parser/inline/ok/0003_where_pred_for.rast
index 6cdfd058b..12f5040f9 100644
--- a/crates/syntax/test_data/parser/inline/ok/0003_where_pred_for.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0003_where_pred_for.rast
@@ -23,7 +23,7 @@ [email protected]
           [email protected] "<"
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] ">"
         [email protected] " "
         [email protected]
@@ -46,7 +46,7 @@ [email protected]
                       [email protected]
                         [email protected] "&"
                         [email protected]
-                          [email protected] "\'a"
+                          [email protected] "'a"
                         [email protected] " "
                         [email protected]
                           [email protected]
diff --git a/crates/syntax/test_data/parser/inline/ok/0006_self_param.rast b/crates/syntax/test_data/parser/inline/ok/0006_self_param.rast
index f0d152d33..d4c8b9d67 100644
--- a/crates/syntax/test_data/parser/inline/ok/0006_self_param.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0006_self_param.rast
@@ -55,7 +55,7 @@ [email protected]
           [email protected]
             [email protected] "&"
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
             [email protected] " "
             [email protected]
               [email protected] "self"
@@ -76,7 +76,7 @@ [email protected]
           [email protected]
             [email protected] "&"
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
             [email protected] " "
             [email protected] "mut"
             [email protected] " "
diff --git a/crates/syntax/test_data/parser/inline/ok/0007_type_param_bounds.rast b/crates/syntax/test_data/parser/inline/ok/0007_type_param_bounds.rast
index 075b438d2..121c3966a 100644
--- a/crates/syntax/test_data/parser/inline/ok/0007_type_param_bounds.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0007_type_param_bounds.rast
@@ -14,7 +14,7 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] " "
           [email protected] "+"
           [email protected] " "
diff --git a/crates/syntax/test_data/parser/inline/ok/0015_continue_expr.rast b/crates/syntax/test_data/parser/inline/ok/0015_continue_expr.rast
index b9e92b57a..b67ea2682 100644
--- a/crates/syntax/test_data/parser/inline/ok/0015_continue_expr.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0015_continue_expr.rast
@@ -27,7 +27,7 @@ [email protected]
               [email protected] "continue"
               [email protected] " "
               [email protected]
-                [email protected] "\'l"
+                [email protected] "'l"
             [email protected] ";"
           [email protected] "\n    "
           [email protected] "}"
diff --git a/crates/syntax/test_data/parser/inline/ok/0028_impl_trait_type.rast b/crates/syntax/test_data/parser/inline/ok/0028_impl_trait_type.rast
index dad4362b7..b44f46f05 100644
--- a/crates/syntax/test_data/parser/inline/ok/0028_impl_trait_type.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0028_impl_trait_type.rast
@@ -32,7 +32,7 @@ [email protected]
                             [email protected] "<"
                             [email protected]
                               [email protected]
-                                [email protected] "\'a"
+                                [email protected] "'a"
                             [email protected] ">"
                   [email protected] ">"
         [email protected] " "
@@ -40,6 +40,6 @@ [email protected]
         [email protected] " "
         [email protected]
           [email protected]
-            [email protected] "\'a"
+            [email protected] "'a"
     [email protected] ";"
   [email protected] "\n"
diff --git a/crates/syntax/test_data/parser/inline/ok/0033_reference_type;.rast b/crates/syntax/test_data/parser/inline/ok/0033_reference_type;.rast
index ac0299268..7cb288bf0 100644
--- a/crates/syntax/test_data/parser/inline/ok/0033_reference_type;.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0033_reference_type;.rast
@@ -25,7 +25,7 @@ [email protected]
     [email protected]
       [email protected] "&"
       [email protected]
-        [email protected] "\'static"
+        [email protected] "'static"
       [email protected] " "
       [email protected]
         [email protected] "("
diff --git a/crates/syntax/test_data/parser/inline/ok/0034_break_expr.rast b/crates/syntax/test_data/parser/inline/ok/0034_break_expr.rast
index 828013d45..783b25338 100644
--- a/crates/syntax/test_data/parser/inline/ok/0034_break_expr.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0034_break_expr.rast
@@ -27,7 +27,7 @@ [email protected]
               [email protected] "break"
               [email protected] " "
               [email protected]
-                [email protected] "\'l"
+                [email protected] "'l"
             [email protected] ";"
           [email protected] "\n        "
           [email protected]
@@ -43,7 +43,7 @@ [email protected]
               [email protected] "break"
               [email protected] " "
               [email protected]
-                [email protected] "\'l"
+                [email protected] "'l"
               [email protected] " "
               [email protected]
                 [email protected] "92"
diff --git a/crates/syntax/test_data/parser/inline/ok/0039_type_arg.rast b/crates/syntax/test_data/parser/inline/ok/0039_type_arg.rast
index 68c0f1c66..11efa23a4 100644
--- a/crates/syntax/test_data/parser/inline/ok/0039_type_arg.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0039_type_arg.rast
@@ -16,7 +16,7 @@ [email protected]
             [email protected] "<"
             [email protected]
               [email protected]
-                [email protected] "\'static"
+                [email protected] "'static"
             [email protected] ","
             [email protected] " "
             [email protected]
diff --git a/crates/syntax/test_data/parser/inline/ok/0045_param_list_opt_patterns.rast b/crates/syntax/test_data/parser/inline/ok/0045_param_list_opt_patterns.rast
index b6f5a5689..abc258b33 100644
--- a/crates/syntax/test_data/parser/inline/ok/0045_param_list_opt_patterns.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0045_param_list_opt_patterns.rast
@@ -34,7 +34,7 @@ [email protected]
                                 [email protected] "<"
                                 [email protected]
                                   [email protected]
-                                    [email protected] "\'a"
+                                    [email protected] "'a"
                                 [email protected] ">"
                     [email protected] ")"
       [email protected] ">"
diff --git a/crates/syntax/test_data/parser/inline/ok/0048_path_type_with_bounds.rast b/crates/syntax/test_data/parser/inline/ok/0048_path_type_with_bounds.rast
index 7df6e190a..e1b88c5db 100644
--- a/crates/syntax/test_data/parser/inline/ok/0048_path_type_with_bounds.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0048_path_type_with_bounds.rast
@@ -32,7 +32,7 @@ [email protected]
                     [email protected] " "
                     [email protected]
                       [email protected]
-                        [email protected] "\'f"
+                        [email protected] "'f"
               [email protected] ">"
     [email protected] " "
     [email protected]
@@ -74,7 +74,7 @@ [email protected]
                     [email protected] " "
                     [email protected]
                       [email protected]
-                        [email protected] "\'f"
+                        [email protected] "'f"
               [email protected] ">"
     [email protected] " "
     [email protected]
diff --git a/crates/syntax/test_data/parser/inline/ok/0055_literal_pattern.rast b/crates/syntax/test_data/parser/inline/ok/0055_literal_pattern.rast
index 68bb43852..acf18fc2b 100644
--- a/crates/syntax/test_data/parser/inline/ok/0055_literal_pattern.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0055_literal_pattern.rast
@@ -49,7 +49,7 @@ [email protected]
           [email protected]
             [email protected]
               [email protected]
-                [email protected] "\'c\'"
+                [email protected] "'c'"
             [email protected] " "
             [email protected] "=>"
             [email protected] " "
diff --git a/crates/syntax/test_data/parser/inline/ok/0056_where_clause.rast b/crates/syntax/test_data/parser/inline/ok/0056_where_clause.rast
index 61dea413d..d42a7e295 100644
--- a/crates/syntax/test_data/parser/inline/ok/0056_where_clause.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0056_where_clause.rast
@@ -13,19 +13,19 @@ [email protected]
       [email protected] "\n   "
       [email protected]
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
         [email protected] ":"
         [email protected] " "
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'b"
+              [email protected] "'b"
           [email protected] " "
           [email protected] "+"
           [email protected] " "
           [email protected]
             [email protected]
-              [email protected] "\'c"
+              [email protected] "'c"
       [email protected] ","
       [email protected] "\n   "
       [email protected]
@@ -57,7 +57,7 @@ [email protected]
           [email protected] " "
           [email protected]
             [email protected]
-              [email protected] "\'static"
+              [email protected] "'static"
       [email protected] ","
       [email protected] "\n   "
       [email protected]
@@ -76,7 +76,7 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
       [email protected] ","
       [email protected] "\n   "
       [email protected]
@@ -108,7 +108,7 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
     [email protected] "\n"
     [email protected]
       [email protected] "{"
diff --git a/crates/syntax/test_data/parser/inline/ok/0065_dyn_trait_type.rast b/crates/syntax/test_data/parser/inline/ok/0065_dyn_trait_type.rast
index 49d26cef4..8f76177d1 100644
--- a/crates/syntax/test_data/parser/inline/ok/0065_dyn_trait_type.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0065_dyn_trait_type.rast
@@ -32,7 +32,7 @@ [email protected]
                             [email protected] "<"
                             [email protected]
                               [email protected]
-                                [email protected] "\'a"
+                                [email protected] "'a"
                             [email protected] ">"
                   [email protected] ">"
         [email protected] " "
@@ -40,6 +40,6 @@ [email protected]
         [email protected] " "
         [email protected]
           [email protected]
-            [email protected] "\'a"
+            [email protected] "'a"
     [email protected] ";"
   [email protected] "\n"
diff --git a/crates/syntax/test_data/parser/inline/ok/0081_for_type.rast b/crates/syntax/test_data/parser/inline/ok/0081_for_type.rast
index 8c909b5af..7958e32e5 100644
--- a/crates/syntax/test_data/parser/inline/ok/0081_for_type.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0081_for_type.rast
@@ -13,7 +13,7 @@ [email protected]
         [email protected] "<"
         [email protected]
           [email protected]
-            [email protected] "\'a"
+            [email protected] "'a"
         [email protected] ">"
       [email protected] " "
       [email protected]
@@ -44,7 +44,7 @@ [email protected]
         [email protected] "<"
         [email protected]
           [email protected]
-            [email protected] "\'a"
+            [email protected] "'a"
         [email protected] ">"
       [email protected] " "
       [email protected]
@@ -62,7 +62,7 @@ [email protected]
             [email protected]
               [email protected] "&"
               [email protected]
-                [email protected] "\'a"
+                [email protected] "'a"
               [email protected] " "
               [email protected]
                 [email protected] "("
@@ -91,7 +91,7 @@ [email protected]
         [email protected] "<"
         [email protected]
           [email protected]
-            [email protected] "\'a"
+            [email protected] "'a"
         [email protected] ">"
       [email protected] " "
       [email protected]
@@ -105,7 +105,7 @@ [email protected]
                 [email protected]
                   [email protected] "&"
                   [email protected]
-                    [email protected] "\'a"
+                    [email protected] "'a"
                   [email protected] " "
                   [email protected]
                     [email protected]
diff --git a/crates/syntax/test_data/parser/inline/ok/0085_expr_literals.rast b/crates/syntax/test_data/parser/inline/ok/0085_expr_literals.rast
index ae838105d..f784e96e0 100644
--- a/crates/syntax/test_data/parser/inline/ok/0085_expr_literals.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0085_expr_literals.rast
@@ -68,7 +68,7 @@ [email protected]
         [email protected] "="
         [email protected] " "
         [email protected]
-          [email protected] "b\'a\'"
+          [email protected] "b'a'"
         [email protected] ";"
       [email protected] "\n    "
       [email protected]
@@ -80,7 +80,7 @@ [email protected]
         [email protected] "="
         [email protected] " "
         [email protected]
-          [email protected] "\'b\'"
+          [email protected] "'b'"
         [email protected] ";"
       [email protected] "\n    "
       [email protected]
diff --git a/crates/syntax/test_data/parser/inline/ok/0109_label.rast b/crates/syntax/test_data/parser/inline/ok/0109_label.rast
index 860dfe608..8540b8520 100644
--- a/crates/syntax/test_data/parser/inline/ok/0109_label.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0109_label.rast
@@ -15,7 +15,7 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
             [email protected] ":"
           [email protected] " "
           [email protected] "loop"
@@ -28,7 +28,7 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'b"
+              [email protected] "'b"
             [email protected] ":"
           [email protected] " "
           [email protected] "while"
@@ -44,7 +44,7 @@ [email protected]
       [email protected]
         [email protected]
           [email protected]
-            [email protected] "\'c"
+            [email protected] "'c"
           [email protected] ":"
         [email protected] " "
         [email protected] "for"
diff --git a/crates/syntax/test_data/parser/inline/ok/0122_generic_lifetime_type_attribute.rast b/crates/syntax/test_data/parser/inline/ok/0122_generic_lifetime_type_attribute.rast
index 840181383..5682bd28c 100644
--- a/crates/syntax/test_data/parser/inline/ok/0122_generic_lifetime_type_attribute.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0122_generic_lifetime_type_attribute.rast
@@ -22,7 +22,7 @@ [email protected]
           [email protected] "]"
         [email protected] " "
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
       [email protected] ","
       [email protected] " "
       [email protected]
@@ -53,7 +53,7 @@ [email protected]
         [email protected]
           [email protected] "&"
           [email protected]
-            [email protected] "\'a"
+            [email protected] "'a"
           [email protected] " "
           [email protected]
             [email protected]
diff --git a/crates/syntax/test_data/parser/inline/ok/0154_no_dyn_trait_leading_for.rast b/crates/syntax/test_data/parser/inline/ok/0154_no_dyn_trait_leading_for.rast
index edfcb288c..860684b29 100644
--- a/crates/syntax/test_data/parser/inline/ok/0154_no_dyn_trait_leading_for.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0154_no_dyn_trait_leading_for.rast
@@ -16,7 +16,7 @@ [email protected]
               [email protected] "<"
               [email protected]
                 [email protected]
-                  [email protected] "\'a"
+                  [email protected] "'a"
               [email protected] ">"
             [email protected] " "
             [email protected]
@@ -28,7 +28,7 @@ [email protected]
                     [email protected] "<"
                     [email protected]
                       [email protected]
-                        [email protected] "\'a"
+                        [email protected] "'a"
                     [email protected] ">"
         [email protected] " "
         [email protected] "+"
diff --git a/crates/syntax/test_data/parser/inline/ok/0161_labeled_block.rast b/crates/syntax/test_data/parser/inline/ok/0161_labeled_block.rast
index c2dea1cc1..47e8859ed 100644
--- a/crates/syntax/test_data/parser/inline/ok/0161_labeled_block.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0161_labeled_block.rast
@@ -15,7 +15,7 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'label"
+              [email protected] "'label"
             [email protected] ":"
           [email protected] " "
           [email protected]
diff --git a/crates/syntax/test_data/parser/ok/0011_outer_attribute.rast b/crates/syntax/test_data/parser/ok/0011_outer_attribute.rast
index ff5877a7b..31f76589d 100644
--- a/crates/syntax/test_data/parser/ok/0011_outer_attribute.rast
+++ b/crates/syntax/test_data/parser/ok/0011_outer_attribute.rast
@@ -21,7 +21,7 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "ignore"
+              [email protected] "Ignore"
       [email protected] "]"
     [email protected] "\n"
     [email protected] "fn"
diff --git a/crates/syntax/test_data/parser/ok/0011_outer_attribute.rs b/crates/syntax/test_data/parser/ok/0011_outer_attribute.rs
index 3d2e01d5c..6f04cb171 100644
--- a/crates/syntax/test_data/parser/ok/0011_outer_attribute.rs
+++ b/crates/syntax/test_data/parser/ok/0011_outer_attribute.rs
@@ -1,5 +1,5 @@
 #[cfg(test)]
-#[ignore]
+#[Ignore]
 fn foo() {}
 
 #[path = "a.rs"]
diff --git a/crates/syntax/test_data/parser/ok/0018_struct_type_params.rast b/crates/syntax/test_data/parser/ok/0018_struct_type_params.rast
index 83e17757b..f845d5cff 100644
--- a/crates/syntax/test_data/parser/ok/0018_struct_type_params.rast
+++ b/crates/syntax/test_data/parser/ok/0018_struct_type_params.rast
@@ -81,7 +81,7 @@ [email protected]
       [email protected] "<"
       [email protected]
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
       [email protected] ">"
     [email protected] ";"
   [email protected] "\n"
@@ -94,7 +94,7 @@ [email protected]
       [email protected] "<"
       [email protected]
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
         [email protected] ":"
       [email protected] ">"
     [email protected] ";"
@@ -108,11 +108,11 @@ [email protected]
       [email protected] "<"
       [email protected]
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
         [email protected] ":"
         [email protected] " "
         [email protected]
-          [email protected] "\'b"
+          [email protected] "'b"
       [email protected] ">"
     [email protected] ";"
   [email protected] "\n"
@@ -125,11 +125,11 @@ [email protected]
       [email protected] "<"
       [email protected]
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
         [email protected] ":"
         [email protected] " "
         [email protected]
-          [email protected] "\'b"
+          [email protected] "'b"
         [email protected] " "
         [email protected] "+"
       [email protected] " "
@@ -145,16 +145,16 @@ [email protected]
       [email protected] "<"
       [email protected]
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
         [email protected] ":"
         [email protected] " "
         [email protected]
-          [email protected] "\'b"
+          [email protected] "'b"
         [email protected] " "
         [email protected] "+"
         [email protected] " "
         [email protected]
-          [email protected] "\'c"
+          [email protected] "'c"
       [email protected] ">"
     [email protected] ";"
   [email protected] "\n"
@@ -167,7 +167,7 @@ [email protected]
       [email protected] "<"
       [email protected]
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
       [email protected] ","
       [email protected] ">"
     [email protected] ";"
@@ -181,12 +181,12 @@ [email protected]
       [email protected] "<"
       [email protected]
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
       [email protected] ","
       [email protected] " "
       [email protected]
         [email protected]
-          [email protected] "\'b"
+          [email protected] "'b"
       [email protected] ">"
     [email protected] ";"
   [email protected] "\n"
@@ -199,21 +199,21 @@ [email protected]
       [email protected] "<"
       [email protected]
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
         [email protected] ":"
         [email protected] " "
         [email protected]
-          [email protected] "\'b"
+          [email protected] "'b"
         [email protected] "+"
       [email protected] ","
       [email protected] " "
       [email protected]
         [email protected]
-          [email protected] "\'b"
+          [email protected] "'b"
         [email protected] ":"
         [email protected] " "
         [email protected]
-          [email protected] "\'c"
+          [email protected] "'c"
       [email protected] ","
       [email protected] ">"
     [email protected] ";"
@@ -258,7 +258,7 @@ [email protected]
       [email protected] "<"
       [email protected]
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
       [email protected] ","
       [email protected] " "
       [email protected]
diff --git a/crates/syntax/test_data/parser/ok/0020_type_param_bounds.rast b/crates/syntax/test_data/parser/ok/0020_type_param_bounds.rast
index 21c564a20..9d4b001ae 100644
--- a/crates/syntax/test_data/parser/ok/0020_type_param_bounds.rast
+++ b/crates/syntax/test_data/parser/ok/0020_type_param_bounds.rast
@@ -42,7 +42,7 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
       [email protected] ">"
     [email protected] ";"
   [email protected] "\n"
@@ -61,7 +61,7 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] " "
           [email protected] "+"
       [email protected] " "
@@ -83,13 +83,13 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] " "
           [email protected] "+"
           [email protected] " "
           [email protected]
             [email protected]
-              [email protected] "\'d"
+              [email protected] "'d"
       [email protected] " "
       [email protected] ">"
     [email protected] ";"
@@ -109,13 +109,13 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] " "
           [email protected] "+"
           [email protected] " "
           [email protected]
             [email protected]
-              [email protected] "\'d"
+              [email protected] "'d"
           [email protected] " "
           [email protected] "+"
           [email protected] " "
@@ -198,7 +198,7 @@ [email protected]
           [email protected] " "
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
       [email protected] ">"
     [email protected] ";"
   [email protected] "\n"
@@ -234,25 +234,25 @@ [email protected]
       [email protected] "<"
       [email protected]
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
         [email protected] ":"
         [email protected] " "
         [email protected]
-          [email protected] "\'d"
+          [email protected] "'d"
       [email protected] ","
       [email protected] " "
       [email protected]
         [email protected]
-          [email protected] "\'d"
+          [email protected] "'d"
         [email protected] ":"
         [email protected] " "
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
         [email protected] " "
         [email protected] "+"
         [email protected] " "
         [email protected]
-          [email protected] "\'b"
+          [email protected] "'b"
       [email protected] ","
       [email protected] " "
       [email protected]
@@ -263,13 +263,13 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] " "
           [email protected] "+"
           [email protected] " "
           [email protected]
             [email protected]
-              [email protected] "\'d"
+              [email protected] "'d"
           [email protected] " "
           [email protected] "+"
           [email protected] " "
diff --git a/crates/syntax/test_data/parser/ok/0030_string_suffixes.rast b/crates/syntax/test_data/parser/ok/0030_string_suffixes.rast
index 80f7f5942..115861585 100644
--- a/crates/syntax/test_data/parser/ok/0030_string_suffixes.rast
+++ b/crates/syntax/test_data/parser/ok/0030_string_suffixes.rast
@@ -20,7 +20,7 @@ [email protected]
         [email protected] "="
         [email protected] " "
         [email protected]
-          [email protected] "\'c\'u32"
+          [email protected] "'c'u32"
         [email protected] ";"
       [email protected] "\n    "
       [email protected]
@@ -44,7 +44,7 @@ [email protected]
         [email protected] "="
         [email protected] " "
         [email protected]
-          [email protected] "b\'b\'_suff"
+          [email protected] "b'b'_suff"
         [email protected] ";"
       [email protected] "\n    "
       [email protected]
diff --git a/crates/syntax/test_data/parser/ok/0032_where_for.rast b/crates/syntax/test_data/parser/ok/0032_where_for.rast
index 0cb2eca33..b527cc3ac 100644
--- a/crates/syntax/test_data/parser/ok/0032_where_for.rast
+++ b/crates/syntax/test_data/parser/ok/0032_where_for.rast
@@ -42,7 +42,7 @@ [email protected]
                 [email protected] "<"
                 [email protected]
                   [email protected]
-                    [email protected] "\'de"
+                    [email protected] "'de"
                 [email protected] ">"
               [email protected] " "
               [email protected]
@@ -54,7 +54,7 @@ [email protected]
                       [email protected] "<"
                       [email protected]
                         [email protected]
-                          [email protected] "\'de"
+                          [email protected] "'de"
                       [email protected] ">"
           [email protected] " "
           [email protected] "+"
diff --git a/crates/syntax/test_data/parser/ok/0033_label_break.rast b/crates/syntax/test_data/parser/ok/0033_label_break.rast
index 487e073ba..4b0f0997e 100644
--- a/crates/syntax/test_data/parser/ok/0033_label_break.rast
+++ b/crates/syntax/test_data/parser/ok/0033_label_break.rast
@@ -17,7 +17,7 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'empty_block"
+              [email protected] "'empty_block"
             [email protected] ":"
           [email protected] " "
           [email protected]
@@ -28,7 +28,7 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'block"
+              [email protected] "'block"
             [email protected] ":"
           [email protected] " "
           [email protected]
@@ -69,7 +69,7 @@ [email protected]
                       [email protected] "break"
                       [email protected] " "
                       [email protected]
-                        [email protected] "\'block"
+                        [email protected] "'block"
                     [email protected] ";"
                   [email protected] "\n        "
                   [email protected] "}"
@@ -109,7 +109,7 @@ [email protected]
                       [email protected] "break"
                       [email protected] " "
                       [email protected]
-                        [email protected] "\'block"
+                        [email protected] "'block"
                     [email protected] ";"
                   [email protected] "\n        "
                   [email protected] "}"
@@ -140,7 +140,7 @@ [email protected]
         [email protected]
           [email protected]
             [email protected]
-              [email protected] "\'block"
+              [email protected] "'block"
             [email protected] ":"
           [email protected] " "
           [email protected]
@@ -171,7 +171,7 @@ [email protected]
                       [email protected] "break"
                       [email protected] " "
                       [email protected]
-                        [email protected] "\'block"
+                        [email protected] "'block"
                       [email protected] " "
                       [email protected]
                         [email protected] "1"
@@ -204,7 +204,7 @@ [email protected]
                       [email protected] "break"
                       [email protected] " "
                       [email protected]
-                        [email protected] "\'block"
+                        [email protected] "'block"
                       [email protected] " "
                       [email protected]
                         [email protected] "2"
diff --git a/crates/syntax/test_data/parser/ok/0035_weird_exprs.rast b/crates/syntax/test_data/parser/ok/0035_weird_exprs.rast
index 20675dbf5..2fa46ad2d 100644
--- a/crates/syntax/test_data/parser/ok/0035_weird_exprs.rast
+++ b/crates/syntax/test_data/parser/ok/0035_weird_exprs.rast
@@ -1378,14 +1378,14 @@ [email protected]
                         [email protected] " "
                         [email protected] "u8"
                         [email protected] "<"
-                        [email protected] "\'u8"
+                        [email protected] "'u8"
                         [email protected] ":"
                         [email protected] " "
-                        [email protected] "\'u8"
+                        [email protected] "'u8"
                         [email protected] " "
                         [email protected] "+"
                         [email protected] " "
-                        [email protected] "\'u8"
+                        [email protected] "'u8"
                         [email protected] ">"
                         [email protected]
                           [email protected] "("
@@ -1393,7 +1393,7 @@ [email protected]
                           [email protected] ":"
                           [email protected] " "
                           [email protected] "&"
-                          [email protected] "\'u8"
+                          [email protected] "'u8"
                           [email protected] " "
                           [email protected] "u8"
                           [email protected] ")"
@@ -1402,7 +1402,7 @@ [email protected]
                         [email protected] ">"
                         [email protected] " "
                         [email protected] "&"
-                        [email protected] "\'u8"
+                        [email protected] "'u8"
                         [email protected] " "
                         [email protected] "u8"
                         [email protected] " "
@@ -1574,7 +1574,7 @@ [email protected]
           [email protected] "<"
           [email protected]
             [email protected]
-              [email protected] "\'union"
+              [email protected] "'union"
           [email protected] ">"
         [email protected] " "
         [email protected]
@@ -1588,7 +1588,7 @@ [email protected]
             [email protected]
               [email protected] "&"
               [email protected]
-                [email protected] "\'union"
+                [email protected] "'union"
               [email protected] " "
               [email protected]
                 [email protected]
@@ -1599,7 +1599,7 @@ [email protected]
                       [email protected] "<"
                       [email protected]
                         [email protected]
-                          [email protected] "\'union"
+                          [email protected] "'union"
                       [email protected] ">"
           [email protected] ","
           [email protected] " "
@@ -1681,7 +1681,7 @@ [email protected]
                           [email protected] "\"\\\\\""
                     [email protected] ","
                     [email protected]
-                      [email protected] "\'🤔\'"
+                      [email protected] "'🤔'"
                     [email protected] ")"
                   [email protected] "/**/"
                   [email protected] ","
diff --git a/crates/syntax/test_data/parser/ok/0051_parameter_attrs.rast b/crates/syntax/test_data/parser/ok/0051_parameter_attrs.rast
index f935a0df5..a7f0f7bc6 100644
--- a/crates/syntax/test_data/parser/ok/0051_parameter_attrs.rast
+++ b/crates/syntax/test_data/parser/ok/0051_parameter_attrs.rast
@@ -181,7 +181,7 @@ [email protected]
                                 [email protected] "<"
                                 [email protected]
                                   [email protected]
-                                    [email protected] "\'a"
+                                    [email protected] "'a"
                                 [email protected] ">"
                     [email protected] ")"
       [email protected] ">"
@@ -359,7 +359,7 @@ [email protected]
           [email protected] "<"
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] ">"
         [email protected]
           [email protected] "("
@@ -394,7 +394,7 @@ [email protected]
           [email protected] "<"
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] ">"
         [email protected]
           [email protected] "("
@@ -411,7 +411,7 @@ [email protected]
             [email protected] " "
             [email protected] "&"
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
             [email protected] " "
             [email protected]
               [email protected] "self"
@@ -430,7 +430,7 @@ [email protected]
           [email protected] "<"
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] ">"
         [email protected]
           [email protected] "("
@@ -447,7 +447,7 @@ [email protected]
             [email protected] " "
             [email protected] "&"
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
             [email protected] " "
             [email protected] "mut"
             [email protected] " "
diff --git a/crates/syntax/test_data/parser/ok/0067_where_for_pred.rast b/crates/syntax/test_data/parser/ok/0067_where_for_pred.rast
index 325e9e655..79e2b2867 100644
--- a/crates/syntax/test_data/parser/ok/0067_where_for_pred.rast
+++ b/crates/syntax/test_data/parser/ok/0067_where_for_pred.rast
@@ -23,7 +23,7 @@ [email protected]
           [email protected] "<"
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] ">"
         [email protected] " "
         [email protected]
@@ -46,7 +46,7 @@ [email protected]
                       [email protected]
                         [email protected] "&"
                         [email protected]
-                          [email protected] "\'a"
+                          [email protected] "'a"
                         [email protected] " "
                         [email protected]
                           [email protected]
@@ -85,13 +85,13 @@ [email protected]
           [email protected] "<"
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] ">"
         [email protected] " "
         [email protected]
           [email protected] "&"
           [email protected]
-            [email protected] "\'a"
+            [email protected] "'a"
           [email protected] " "
           [email protected]
             [email protected]
@@ -138,7 +138,7 @@ [email protected]
           [email protected] "<"
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] ">"
         [email protected] " "
         [email protected]
@@ -146,7 +146,7 @@ [email protected]
           [email protected]
             [email protected] "&"
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
             [email protected] " "
             [email protected]
               [email protected]
@@ -169,7 +169,7 @@ [email protected]
                       [email protected]
                         [email protected] "&"
                         [email protected]
-                          [email protected] "\'a"
+                          [email protected] "'a"
                         [email protected] " "
                         [email protected]
                           [email protected]
@@ -208,7 +208,7 @@ [email protected]
           [email protected] "<"
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] ">"
         [email protected] " "
         [email protected]
@@ -216,7 +216,7 @@ [email protected]
           [email protected]
             [email protected] "&"
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
             [email protected] " "
             [email protected]
               [email protected]
@@ -277,7 +277,7 @@ [email protected]
           [email protected] "<"
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] ">"
         [email protected] " "
         [email protected]
@@ -288,7 +288,7 @@ [email protected]
                 [email protected]
                   [email protected] "&"
                   [email protected]
-                    [email protected] "\'a"
+                    [email protected] "'a"
                   [email protected] " "
                   [email protected]
                     [email protected]
@@ -348,7 +348,7 @@ [email protected]
           [email protected] "<"
           [email protected]
             [email protected]
-              [email protected] "\'a"
+              [email protected] "'a"
           [email protected] ">"
         [email protected] " "
         [email protected]
@@ -357,7 +357,7 @@ [email protected]
             [email protected] "<"
             [email protected]
               [email protected]
-                [email protected] "\'b"
+                [email protected] "'b"
             [email protected] ">"
           [email protected] " "
           [email protected]
@@ -368,7 +368,7 @@ [email protected]
                 [email protected]
                   [email protected] "&"
                   [email protected]
-                    [email protected] "\'a"
+                    [email protected] "'a"
                   [email protected] " "
                   [email protected]
                     [email protected]
@@ -381,7 +381,7 @@ [email protected]
                 [email protected]
                   [email protected] "&"
                   [email protected]
-                    [email protected] "\'b"
+                    [email protected] "'b"
                   [email protected] " "
                   [email protected]
                     [email protected]
diff --git a/crates/syntax/test_data/parser/ok/0069_multi_trait_object.rast b/crates/syntax/test_data/parser/ok/0069_multi_trait_object.rast
index 8d3e187ae..026c776e2 100644
--- a/crates/syntax/test_data/parser/ok/0069_multi_trait_object.rast
+++ b/crates/syntax/test_data/parser/ok/0069_multi_trait_object.rast
@@ -8,7 +8,7 @@ [email protected]
       [email protected] "<"
       [email protected]
         [email protected]
-          [email protected] "\'a"
+          [email protected] "'a"
       [email protected] ">"
     [email protected] " "
     [email protected] "="
@@ -16,7 +16,7 @@ [email protected]
     [email protected]
       [email protected] "&"
       [email protected]
-        [email protected] "\'a"
+        [email protected] "'a"
       [email protected] " "
       [email protected]
         [email protected] "("
@@ -112,7 +112,7 @@ [email protected]
               [email protected] " "
               [email protected]
                 [email protected]
-                  [email protected] "\'static"
+                  [email protected] "'static"
           [email protected] ")"
     [email protected] ";"
   [email protected] "\n"
diff --git a/crates/test_utils/src/fixture.rs b/crates/test_utils/src/fixture.rs
index d0bddf7d8..44656267f 100644
--- a/crates/test_utils/src/fixture.rs
+++ b/crates/test_utils/src/fixture.rs
@@ -77,6 +77,11 @@ pub struct Fixture {
     pub introduce_new_source_root: bool,
 }
 
+pub struct MiniCore {
+    activated_flags: Vec<String>,
+    valid_flags: Vec<String>,
+}
+
 impl Fixture {
     /// Parses text which looks like this:
     ///
@@ -86,12 +91,28 @@ impl Fixture {
     ///  line 2
     ///  //- other meta
     ///  ```
-    pub fn parse(ra_fixture: &str) -> Vec<Fixture> {
+    ///
+    /// Fixture can also start with a minicore declaration:
+    ///
+    /// ```
+    /// //- minicore: sized
+    /// ```
+    ///
+    /// That will include a subset of `libcore` into the fixture, see
+    /// `minicore.rs` for what's available.
+    pub fn parse(ra_fixture: &str) -> (Option<MiniCore>, Vec<Fixture>) {
         let fixture = trim_indent(ra_fixture);
-
+        let mut fixture = fixture.as_str();
+        let mut mini_core = None;
         let mut res: Vec<Fixture> = Vec::new();
 
-        let default = if ra_fixture.contains("//-") { None } else { Some("//- /main.rs") };
+        if fixture.starts_with("//- minicore:") {
+            let first_line = fixture.split_inclusive('\n').next().unwrap();
+            mini_core = Some(MiniCore::parse(first_line));
+            fixture = &fixture[first_line.len()..];
+        }
+
+        let default = if fixture.contains("//-") { None } else { Some("//- /main.rs") };
 
         for (ix, line) in default.into_iter().chain(fixture.split_inclusive('\n')).enumerate() {
             if line.contains("//-") {
@@ -108,12 +129,22 @@ impl Fixture {
             if line.starts_with("//-") {
                 let meta = Fixture::parse_meta_line(line);
                 res.push(meta)
-            } else if let Some(entry) = res.last_mut() {
-                entry.text.push_str(line);
+            } else {
+                if line.starts_with("// ")
+                    && line.contains(':')
+                    && !line.contains("::")
+                    && line.chars().all(|it| !it.is_uppercase())
+                {
+                    panic!("looks like invalid metadata line: {:?}", line)
+                }
+
+                if let Some(entry) = res.last_mut() {
+                    entry.text.push_str(line);
+                }
             }
         }
 
-        res
+        (mini_core, res)
     }
 
     //- /lib.rs crate:foo deps:bar,baz cfg:foo=a,bar=b env:OUTDIR=path/to,OTHER=foo
@@ -123,7 +154,7 @@ impl Fixture {
         let components = meta.split_ascii_whitespace().collect::<Vec<_>>();
 
         let path = components[0].to_string();
-        assert!(path.starts_with('/'));
+        assert!(path.starts_with('/'), "fixture path does not start with `/`: {:?}", path);
 
         let mut krate = None;
         let mut deps = Vec::new();
@@ -133,7 +164,9 @@ impl Fixture {
         let mut env = FxHashMap::default();
         let mut introduce_new_source_root = false;
         for component in components[1..].iter() {
-            let (key, value) = component.split_once(':').unwrap();
+            let (key, value) = component
+                .split_once(':')
+                .unwrap_or_else(|| panic!("invalid meta line: {:?}", meta));
             match key {
                 "crate" => krate = Some(value.to_string()),
                 "deps" => deps = value.split(',').map(|it| it.to_string()).collect(),
@@ -172,6 +205,139 @@ impl Fixture {
     }
 }
 
+impl MiniCore {
+    fn has_flag(&self, flag: &str) -> bool {
+        self.activated_flags.iter().any(|it| it == flag)
+    }
+
+    #[track_caller]
+    fn assert_valid_flag(&self, flag: &str) {
+        if !self.valid_flags.iter().any(|it| it == flag) {
+            panic!("invalid flag: {:?}, valid flags: {:?}", flag, self.valid_flags);
+        }
+    }
+
+    fn parse(line: &str) -> MiniCore {
+        let mut res = MiniCore { activated_flags: Vec::new(), valid_flags: Vec::new() };
+
+        let line = line.strip_prefix("//- minicore:").unwrap().trim();
+        for entry in line.split(", ") {
+            if res.has_flag(entry) {
+                panic!("duplicate minicore flag: {:?}", entry)
+            }
+            res.activated_flags.push(entry.to_string())
+        }
+
+        res
+    }
+
+    /// Strips parts of minicore.rs which are flagged by inactive flags.
+    ///
+    /// This is probably over-engineered to support flags dependencies.
+    pub fn source_code(mut self) -> String {
+        let mut buf = String::new();
+        let raw_mini_core = include_str!("./minicore.rs");
+        let mut lines = raw_mini_core.split_inclusive('\n');
+
+        let mut parsing_flags = false;
+        let mut implications = Vec::new();
+
+        // Parse `//!` preamble and extract flags and dependencies.
+        for line in lines.by_ref() {
+            let line = match line.strip_prefix("//!") {
+                Some(it) => it,
+                None => {
+                    assert!(line.trim().is_empty());
+                    break;
+                }
+            };
+
+            if parsing_flags {
+                let (flag, deps) = line.split_once(':').unwrap();
+                let flag = flag.trim();
+                self.valid_flags.push(flag.to_string());
+                for dep in deps.split(", ") {
+                    let dep = dep.trim();
+                    if !dep.is_empty() {
+                        self.assert_valid_flag(dep);
+                        implications.push((flag, dep));
+                    }
+                }
+            }
+
+            if line.contains("Available flags:") {
+                parsing_flags = true;
+            }
+        }
+
+        for flag in &self.activated_flags {
+            self.assert_valid_flag(flag);
+        }
+
+        // Fixed point loop to compute transitive closure of flags.
+        loop {
+            let mut changed = false;
+            for &(u, v) in implications.iter() {
+                if self.has_flag(u) && !self.has_flag(v) {
+                    self.activated_flags.push(v.to_string());
+                    changed = true;
+                }
+            }
+            if !changed {
+                break;
+            }
+        }
+
+        let mut active_regions = Vec::new();
+        let mut seen_regions = Vec::new();
+        for line in lines {
+            let trimmed = line.trim();
+            if let Some(region) = trimmed.strip_prefix("// region:") {
+                active_regions.push(region);
+                continue;
+            }
+            if let Some(region) = trimmed.strip_prefix("// endregion:") {
+                let prev = active_regions.pop().unwrap();
+                assert_eq!(prev, region);
+                continue;
+            }
+
+            let mut line_region = false;
+            if let Some(idx) = trimmed.find("// :") {
+                line_region = true;
+                active_regions.push(&trimmed[idx + "// :".len()..]);
+            }
+
+            let mut keep = true;
+            for &region in &active_regions {
+                assert!(
+                    !region.starts_with(' '),
+                    "region marker starts with a space: {:?}",
+                    region
+                );
+                self.assert_valid_flag(region);
+                seen_regions.push(region);
+                keep &= self.has_flag(region);
+            }
+
+            if keep {
+                buf.push_str(line)
+            }
+            if line_region {
+                active_regions.pop().unwrap();
+            }
+        }
+
+        for flag in &self.valid_flags {
+            if !seen_regions.iter().any(|it| it == flag) {
+                panic!("unused minicore flag: {:?}", flag);
+            }
+        }
+        format!("{}", buf);
+        buf
+    }
+}
+
 #[test]
 #[should_panic]
 fn parse_fixture_checks_further_indented_metadata() {
@@ -189,12 +355,14 @@ fn parse_fixture_checks_further_indented_metadata() {
 
 #[test]
 fn parse_fixture_gets_full_meta() {
-    let parsed = Fixture::parse(
-        r"
-    //- /lib.rs crate:foo deps:bar,baz cfg:foo=a,bar=b,atom env:OUTDIR=path/to,OTHER=foo
-    mod m;
-    ",
+    let (mini_core, parsed) = Fixture::parse(
+        r#"
+//- minicore: coerce_unsized
+//- /lib.rs crate:foo deps:bar,baz cfg:foo=a,bar=b,atom env:OUTDIR=path/to,OTHER=foo
+mod m;
+"#,
     );
+    assert_eq!(mini_core.unwrap().activated_flags, vec!["coerce_unsized".to_string()]);
     assert_eq!(1, parsed.len());
 
     let meta = &parsed[0];
diff --git a/crates/test_utils/src/lib.rs b/crates/test_utils/src/lib.rs
index b2fe25f82..d9c22c180 100644
--- a/crates/test_utils/src/lib.rs
+++ b/crates/test_utils/src/lib.rs
@@ -11,6 +11,7 @@ mod fixture;
 mod assert_linear;
 
 use std::{
+    collections::BTreeMap,
     convert::{TryFrom, TryInto},
     env, fs,
     path::{Path, PathBuf},
@@ -23,7 +24,10 @@ use text_size::{TextRange, TextSize};
 pub use dissimilar::diff as __diff;
 pub use rustc_hash::FxHashMap;
 
-pub use crate::{assert_linear::AssertLinear, fixture::Fixture};
+pub use crate::{
+    assert_linear::AssertLinear,
+    fixture::{Fixture, MiniCore},
+};
 
 pub const CURSOR_MARKER: &str = "$0";
 pub const ESCAPED_CURSOR_MARKER: &str = "\\$0";
@@ -202,14 +206,25 @@ pub fn add_cursor(text: &str, offset: TextSize) -> String {
 ///
 /// // ^^^ first line
 /// //   | second line
+///
+/// Annotations point to the last line that actually was long enough for the
+/// range, not counting annotations themselves. So overlapping annotations are
+/// possible:
+/// ```no_run
+/// // stuff        other stuff
+/// // ^^ 'st'
+/// // ^^^^^ 'stuff'
+/// //              ^^^^^^^^^^^ 'other stuff'
+/// ```
 pub fn extract_annotations(text: &str) -> Vec<(TextRange, String)> {
     let mut res = Vec::new();
-    let mut prev_line_start: Option<TextSize> = Some(0.into());
+    // map from line length to beginning of last line that had that length
+    let mut line_start_map = BTreeMap::new();
     let mut line_start: TextSize = 0.into();
     let mut prev_line_annotations: Vec<(TextSize, usize)> = Vec::new();
     for line in text.split_inclusive('\n') {
         let mut this_line_annotations = Vec::new();
-        if let Some(idx) = line.find("//") {
+        let line_length = if let Some(idx) = line.find("//") {
             let annotation_offset = TextSize::of(&line[..idx + "//".len()]);
             for annotation in extract_line_annotations(&line[idx + "//".len()..]) {
                 match annotation {
@@ -219,7 +234,9 @@ pub fn extract_annotations(text: &str) -> Vec<(TextRange, String)> {
                         let range = if file {
                             TextRange::up_to(TextSize::of(text))
                         } else {
-                            range + prev_line_start.unwrap()
+                            let line_start = line_start_map.range(range.end()..).next().unwrap();
+
+                            range + line_start.1
                         };
                         res.push((range, content))
                     }
@@ -235,9 +252,14 @@ pub fn extract_annotations(text: &str) -> Vec<(TextRange, String)> {
                     }
                 }
             }
-        }
+            idx.try_into().unwrap()
+        } else {
+            TextSize::of(line)
+        };
+
+        line_start_map = line_start_map.split_off(&line_length);
+        line_start_map.insert(line_length, line_start);
 
-        prev_line_start = Some(line_start);
         line_start += TextSize::of(line);
 
         prev_line_annotations = this_line_annotations;
@@ -293,7 +315,7 @@ fn extract_line_annotations(mut line: &str) -> Vec<LineAnnotation> {
 }
 
 #[test]
-fn test_extract_annotations() {
+fn test_extract_annotations_1() {
     let text = stdx::trim_indent(
         r#"
 fn main() {
@@ -318,6 +340,25 @@ fn main() {
     assert_eq!(res[3].0.len(), 115);
 }
 
+#[test]
+fn test_extract_annotations_2() {
+    let text = stdx::trim_indent(
+        r#"
+fn main() {
+    (x,   y);
+   //^ a
+      //  ^ b
+  //^^^^^^^^ c
+}"#,
+    );
+    let res = extract_annotations(&text)
+        .into_iter()
+        .map(|(range, ann)| (&text[range], ann))
+        .collect::<Vec<_>>();
+
+    assert_eq!(res, [("x", "a".into()), ("y", "b".into()), ("(x,   y)", "c".into())]);
+}
+
 /// Returns `false` if slow tests should not run, otherwise returns `true` and
 /// also creates a file at `./target/.slow_tests_cookie` which serves as a flag
 /// that slow tests did run.
diff --git a/crates/test_utils/src/minicore.rs b/crates/test_utils/src/minicore.rs
new file mode 100644
index 000000000..ce6ad8541
--- /dev/null
+++ b/crates/test_utils/src/minicore.rs
@@ -0,0 +1,549 @@
+//! This is a fixture we use for tests that need lang items.
+//!
+//! We want to include the minimal subset of core for each test, so this file
+//! supports "conditional compilation". Tests use the following syntax to include minicore:
+//!
+//!  //- minicore: flag1, flag2
+//!
+//! We then strip all the code marked with other flags.
+//!
+//! Available flags:
+//!     sized:
+//!     unsize: sized
+//!     coerce_unsized: unsize
+//!     slice:
+//!     range:
+//!     deref: sized
+//!     deref_mut: deref
+//!     index: sized
+//!     fn:
+//!     pin:
+//!     future: pin
+//!     option:
+//!     result:
+//!     iterator: option
+//!     iterators: iterator, fn
+//!     default: sized
+//!     clone: sized
+//!     copy: clone
+//!     from: sized
+//!     eq: sized
+//!     ord: eq, option
+//!     derive:
+
+pub mod marker {
+    // region:sized
+    #[lang = "sized"]
+    #[fundamental]
+    #[rustc_specialization_trait]
+    pub trait Sized {}
+    // endregion:sized
+
+    // region:unsize
+    #[lang = "unsize"]
+    pub trait Unsize<T: ?Sized> {}
+    // endregion:unsize
+
+    // region:copy
+    #[lang = "copy"]
+    pub trait Copy: Clone {}
+    // region:derive
+    #[rustc_builtin_macro]
+    pub macro Copy($item:item) {}
+    // endregion:derive
+
+    mod copy_impls {
+        use super::Copy;
+
+        macro_rules! impl_copy {
+            ($($t:ty)*) => {
+                $(
+                    impl Copy for $t {}
+                )*
+            }
+        }
+
+        impl_copy! {
+            usize u8 u16 u32 u64 u128
+            isize i8 i16 i32 i64 i128
+            f32 f64
+            bool char
+        }
+
+        impl<T: ?Sized> Copy for *const T {}
+        impl<T: ?Sized> Copy for *mut T {}
+        impl<T: ?Sized> Copy for &T {}
+    }
+    // endregion:copy
+}
+
+// region:default
+pub mod default {
+    pub trait Default: Sized {
+        fn default() -> Self;
+    }
+}
+// endregion:default
+
+// region:clone
+pub mod clone {
+    #[lang = "clone"]
+    pub trait Clone: Sized {
+        fn clone(&self) -> Self;
+    }
+    // region:derive
+    #[rustc_builtin_macro]
+    pub macro Clone($item:item) {}
+    // endregion:derive
+}
+// endregion:clone
+
+// region:from
+pub mod convert {
+    pub trait From<T>: Sized {
+        fn from(_: T) -> Self;
+    }
+    pub trait Into<T>: Sized {
+        fn into(self) -> T;
+    }
+
+    impl<T, U> Into<U> for T
+    where
+        U: From<T>,
+    {
+        fn into(self) -> U {
+            U::from(self)
+        }
+    }
+
+    impl<T> From<T> for T {
+        fn from(t: T) -> T {
+            t
+        }
+    }
+}
+// endregion:from
+
+pub mod ops {
+    // region:coerce_unsized
+    mod unsize {
+        use crate::marker::Unsize;
+
+        #[lang = "coerce_unsized"]
+        pub trait CoerceUnsized<T: ?Sized> {}
+
+        impl<'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<&'a mut U> for &'a mut T {}
+        impl<'a, 'b: 'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<&'a U> for &'b mut T {}
+        impl<'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*mut U> for &'a mut T {}
+        impl<'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*const U> for &'a mut T {}
+
+        impl<'a, 'b: 'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<&'a U> for &'b T {}
+        impl<'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*const U> for &'a T {}
+
+        impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*mut U> for *mut T {}
+        impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*const U> for *mut T {}
+        impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*const U> for *const T {}
+    }
+    pub use self::unsize::CoerceUnsized;
+    // endregion:coerce_unsized
+
+    // region:deref
+    mod deref {
+        #[lang = "deref"]
+        pub trait Deref {
+            #[lang = "deref_target"]
+            type Target: ?Sized;
+            fn deref(&self) -> &Self::Target;
+        }
+        // region:deref_mut
+        #[lang = "deref_mut"]
+        pub trait DerefMut: Deref {
+            fn deref_mut(&mut self) -> &mut Self::Target;
+        }
+        // endregion:deref_mut
+    }
+    pub use self::deref::{
+        Deref,
+        DerefMut, // :deref_mut
+    };
+    // endregion:deref
+
+    // region:index
+    mod index {
+        #[lang = "index"]
+        pub trait Index<Idx: ?Sized> {
+            type Output: ?Sized;
+            fn index(&self, index: Idx) -> &Self::Output;
+        }
+        #[lang = "index_mut"]
+        pub trait IndexMut<Idx: ?Sized>: Index<Idx> {
+            fn index_mut(&mut self, index: Idx) -> &mut Self::Output;
+        }
+
+        // region:slice
+        impl<T, I> Index<I> for [T]
+        where
+            I: SliceIndex<[T]>,
+        {
+            type Output = I::Output;
+            fn index(&self, index: I) -> &I::Output {
+                loop {}
+            }
+        }
+        impl<T, I> IndexMut<I> for [T]
+        where
+            I: SliceIndex<[T]>,
+        {
+            fn index_mut(&mut self, index: I) -> &mut I::Output {
+                loop {}
+            }
+        }
+
+        pub unsafe trait SliceIndex<T: ?Sized> {
+            type Output: ?Sized;
+        }
+        unsafe impl<T> SliceIndex<[T]> for usize {
+            type Output = T;
+        }
+        // endregion:slice
+    }
+    pub use self::index::{Index, IndexMut};
+    // endregion:index
+
+    // region:range
+    mod range {
+        #[lang = "RangeFull"]
+        pub struct RangeFull;
+
+        #[lang = "Range"]
+        pub struct Range<Idx> {
+            pub start: Idx,
+            pub end: Idx,
+        }
+
+        #[lang = "RangeFrom"]
+        pub struct RangeFrom<Idx> {
+            pub start: Idx,
+        }
+
+        #[lang = "RangeTo"]
+        pub struct RangeTo<Idx> {
+            pub end: Idx,
+        }
+
+        #[lang = "RangeInclusive"]
+        pub struct RangeInclusive<Idx> {
+            pub(crate) start: Idx,
+            pub(crate) end: Idx,
+            pub(crate) exhausted: bool,
+        }
+
+        #[lang = "RangeToInclusive"]
+        pub struct RangeToInclusive<Idx> {
+            pub end: Idx,
+        }
+    }
+    pub use self::range::{Range, RangeFrom, RangeFull, RangeTo};
+    pub use self::range::{RangeInclusive, RangeToInclusive};
+    // endregion:range
+
+    // region:fn
+    mod function {
+        #[lang = "fn"]
+        #[fundamental]
+        pub trait Fn<Args>: FnMut<Args> {}
+
+        #[lang = "fn_mut"]
+        #[fundamental]
+        pub trait FnMut<Args>: FnOnce<Args> {}
+
+        #[lang = "fn_once"]
+        #[fundamental]
+        pub trait FnOnce<Args> {
+            #[lang = "fn_once_output"]
+            type Output;
+        }
+    }
+    pub use self::function::{Fn, FnMut, FnOnce};
+    // endregion:fn
+}
+
+// region:eq
+pub mod cmp {
+    #[lang = "eq"]
+    pub trait PartialEq<Rhs: ?Sized = Self> {
+        fn eq(&self, other: &Rhs) -> bool;
+    }
+
+    pub trait Eq: PartialEq<Self> {}
+
+    // region:derive
+    #[rustc_builtin_macro]
+    pub macro PartialEq($item:item) {}
+    #[rustc_builtin_macro]
+    pub macro Eq($item:item) {}
+    // endregion:derive
+
+    // region:ord
+    #[lang = "partial_ord"]
+    pub trait PartialOrd<Rhs: ?Sized = Self>: PartialEq<Rhs> {
+        fn partial_cmp(&self, other: &Rhs) -> Option<Ordering>;
+    }
+
+    pub trait Ord: Eq + PartialOrd<Self> {
+        fn cmp(&self, other: &Self) -> Ordering;
+    }
+
+    pub enum Ordering {
+        Less = -1,
+        Equal = 0,
+        Greater = 1,
+    }
+
+    // region:derive
+    #[rustc_builtin_macro]
+    pub macro PartialOrd($item:item) {}
+    #[rustc_builtin_macro]
+    pub macro Ord($item:item) {}
+    // endregion:derive
+
+    // endregion:ord
+}
+// endregion:eq
+
+// region:slice
+pub mod slice {
+    #[lang = "slice"]
+    impl<T> [T] {
+        pub fn len(&self) -> usize {
+            loop {}
+        }
+    }
+}
+// endregion:slice
+
+// region:option
+pub mod option {
+    pub enum Option<T> {
+        #[lang = "None"]
+        None,
+        #[lang = "Some"]
+        Some(T),
+    }
+}
+// endregion:option
+
+// region:result
+pub mod result {
+    pub enum Result<T, E> {
+        #[lang = "Ok"]
+        Ok(T),
+        #[lang = "Err"]
+        Err(E),
+    }
+}
+// endregion:result
+
+// region:pin
+pub mod pin {
+    #[lang = "pin"]
+    #[fundamental]
+    pub struct Pin<P> {
+        pointer: P,
+    }
+}
+// endregion:pin
+
+// region:future
+pub mod future {
+    use crate::{
+        pin::Pin,
+        task::{Context, Poll},
+    };
+
+    #[lang = "future_trait"]
+    pub trait Future {
+        type Output;
+        #[lang = "poll"]
+        fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>;
+    }
+}
+pub mod task {
+    pub enum Poll<T> {
+        #[lang = "Ready"]
+        Ready(T),
+        #[lang = "Pending"]
+        Pending,
+    }
+
+    pub struct Context<'a> {
+        waker: &'a (),
+    }
+}
+// endregion:future
+
+// region:iterator
+pub mod iter {
+    // region:iterators
+    mod adapters {
+        pub struct Take<I> {
+            iter: I,
+            n: usize,
+        }
+        impl<I> Iterator for Take<I>
+        where
+            I: Iterator,
+        {
+            type Item = <I as Iterator>::Item;
+
+            fn next(&mut self) -> Option<<I as Iterator>::Item> {
+                loop {}
+            }
+        }
+
+        pub struct FilterMap<I, F> {
+            iter: I,
+            f: F,
+        }
+        impl<B, I: Iterator, F> Iterator for FilterMap<I, F>
+        where
+            F: FnMut(I::Item) -> Option<B>,
+        {
+            type Item = B;
+
+            #[inline]
+            fn next(&mut self) -> Option<B> {
+                loop {}
+            }
+        }
+    }
+    pub use self::adapters::Take;
+
+    mod sources {
+        mod repeat {
+            pub fn repeat<T>(elt: T) -> Repeat<T> {
+                loop {}
+            }
+
+            pub struct Repeat<A> {
+                element: A,
+            }
+
+            impl<A> Iterator for Repeat<A> {
+                type Item = A;
+
+                fn next(&mut self) -> Option<A> {
+                    loop {}
+                }
+            }
+        }
+        pub use self::repeat::{repeat, Repeat};
+    }
+    pub use self::sources::{repeat, Repeat};
+    // endregion:iterators
+
+    mod traits {
+        mod iterator {
+            use super::super::Take;
+
+            pub trait Iterator {
+                type Item;
+                #[lang = "next"]
+                fn next(&mut self) -> Option<Self::Item>;
+                fn nth(&mut self, n: usize) -> Option<Self::Item> {
+                    loop {}
+                }
+                fn by_ref(&mut self) -> &mut Self
+                where
+                    Self: Sized,
+                {
+                    self
+                }
+                // region:iterators
+                fn take(self, n: usize) -> crate::iter::Take<Self> {
+                    loop {}
+                }
+                fn filter_map<B, F>(self, f: F) -> crate::iter::FilterMap<Self, F>
+                where
+                    Self: Sized,
+                    F: FnMut(Self::Item) -> Option<B>,
+                {
+                    loop {}
+                }
+                // endregion:iterators
+            }
+            impl<I: Iterator + ?Sized> Iterator for &mut I {
+                type Item = I::Item;
+                fn next(&mut self) -> Option<I::Item> {
+                    (**self).next()
+                }
+            }
+        }
+        pub use self::iterator::Iterator;
+
+        mod collect {
+            pub trait IntoIterator {
+                type Item;
+                type IntoIter: Iterator<Item = Self::Item>;
+                #[lang = "into_iter"]
+                fn into_iter(self) -> Self::IntoIter;
+            }
+            impl<I: Iterator> IntoIterator for I {
+                type Item = I::Item;
+                type IntoIter = I;
+                fn into_iter(self) -> I {
+                    self
+                }
+            }
+        }
+        pub use self::collect::IntoIterator;
+    }
+    pub use self::traits::{IntoIterator, Iterator};
+}
+// endregion:iterator
+
+// region:derive
+mod macros {
+    pub(crate) mod builtin {
+        #[rustc_builtin_macro]
+        pub macro derive($item:item) {
+            /* compiler built-in */
+        }
+    }
+}
+// endregion:derive
+
+pub mod prelude {
+    pub mod v1 {
+        pub use crate::{
+            clone::Clone,                       // :clone
+            cmp::{Eq, PartialEq},               // :eq
+            cmp::{Ord, PartialOrd},             // :ord
+            convert::{From, Into},              // :from
+            default::Default,                   // :default
+            iter::{IntoIterator, Iterator},     // :iterator
+            macros::builtin::derive,            // :derive
+            marker::Copy,                       // :copy
+            marker::Sized,                      // :sized
+            ops::{Fn, FnMut, FnOnce},           // :fn
+            option::Option::{self, None, Some}, // :option
+            result::Result::{self, Err, Ok},    // :result
+        };
+    }
+
+    pub mod rust_2015 {
+        pub use super::v1::*;
+    }
+
+    pub mod rust_2018 {
+        pub use super::v1::*;
+    }
+
+    pub mod rust_2021 {
+        pub use super::v1::*;
+    }
+}
+
+#[prelude_import]
+#[allow(unused)]
+use prelude::v1::*;
diff --git a/crates/vfs/src/vfs_path.rs b/crates/vfs/src/vfs_path.rs
index 2b3d7fd84..ef2d7657a 100644
--- a/crates/vfs/src/vfs_path.rs
+++ b/crates/vfs/src/vfs_path.rs
@@ -389,7 +389,7 @@ impl VirtualPath {
 
             match (file_stem, extension) {
                 (None, None) => None,
-                (None, Some(_)) | (Some(""), Some(_)) => Some((file_name, None)),
+                (None | Some(""), Some(_)) => Some((file_name, None)),
                 (Some(file_stem), extension) => Some((file_stem, extension)),
             }
         }
diff --git a/docs/dev/debugging.md b/docs/dev/debugging.md
index 5876e71bc..48caec1d8 100644
--- a/docs/dev/debugging.md
+++ b/docs/dev/debugging.md
@@ -65,6 +65,11 @@ If you need to debug the server from the very beginning, including its initializ
     }
 ```
 
+However for this to work, you will need to enable debug_assertions in your build
+```rust
+RUSTFLAGS='--cfg debug_assertions' cargo build --release
+```
+
 ## Demo
 
 - [Debugging TypeScript VScode extension](https://www.youtube.com/watch?v=T-hvpK6s4wM).
diff --git a/docs/dev/style.md b/docs/dev/style.md
index 96dd684b3..84485ea28 100644
--- a/docs/dev/style.md
+++ b/docs/dev/style.md
@@ -174,6 +174,13 @@ Instead, explicitly check for `None`, `Err`, etc.
 `rust-analyzer` is not a library, we don't need to test for API misuse, and we have to handle any user input without panics.
 Panic messages in the logs from the `#[should_panic]` tests are confusing.
 
+## `#[ignore]`
+
+Do not `#[ignore]` tests.
+If the test currently does not work, assert the wrong behavior and add a fixme explaining why it is wrong.
+
+**Rationale:** noticing when the behavior is fixed, making sure that even the wrong behavior is acceptable (ie, not a panic).
+
 ## Function Preconditions
 
 Express function preconditions in types and force the caller to provide them (rather than checking in callee):
diff --git a/docs/user/.gitignore b/docs/user/.gitignore
new file mode 100644
index 000000000..c32b1bcec
--- /dev/null
+++ b/docs/user/.gitignore
@@ -0,0 +1 @@
+manual.html
diff --git a/docs/user/generated_config.adoc b/docs/user/generated_config.adoc
index 4105d784f..cc7fdd38f 100644
--- a/docs/user/generated_config.adoc
+++ b/docs/user/generated_config.adoc
@@ -18,6 +18,11 @@ The path structure for newly inserted paths to use.
 --
 Group inserted imports by the [following order](https://rust-analyzer.github.io/manual.html#auto-import). Groups are separated by newlines.
 --
+[[rust-analyzer.assist.allowMergingIntoGlobImports]]rust-analyzer.assist.allowMergingIntoGlobImports (default: `true`)::
++
+--
+Whether to allow import insertion to merge new imports into single path glob imports like `use std::fmt::*;`.
+--
 [[rust-analyzer.callInfo.full]]rust-analyzer.callInfo.full (default: `true`)::
 +
 --
@@ -34,6 +39,11 @@ Automatically refresh project info via `cargo metadata` on
 --
 Activate all available features (`--all-features`).
 --
+[[rust-analyzer.cargo.unsetTest]]rust-analyzer.cargo.unsetTest (default: `["core"]`)::
++
+--
+Unsets `#[cfg(test)]` for the specified crates.
+--
 [[rust-analyzer.cargo.features]]rust-analyzer.cargo.features (default: `[]`)::
 +
 --
diff --git a/docs/user/manual.adoc b/docs/user/manual.adoc
index 9a8d76700..816e094c2 100644
--- a/docs/user/manual.adoc
+++ b/docs/user/manual.adoc
@@ -201,6 +201,15 @@ $ eselect repository enable guru && emaint sync -r guru
 $ emerge rust-analyzer-bin
 ----
 
+==== macOS
+
+The `rust-analyzer` binary can be installed via https://brew.sh/[Homebrew].
+
+[source,bash]
+----
+$ brew install rust-analyzer
+----
+
 === Emacs
 
 Note this excellent https://robert.kra.hn/posts/2021-02-07_rust-with-emacs/[guide] from https://github.com/rksm[@rksm].
@@ -609,9 +618,14 @@ Here is a **non-exhaustive** list of ways to make rust-analyzer execute arbitrar
 * VS Code plugin reads configuration from project directory, and that can be used to override paths to various executables, like `rustfmt` or `rust-analyzer` itself.
 * rust-analyzer's syntax trees library uses a lot of `unsafe` and hasn't been properly audited for memory safety.
 
-rust-analyzer itself doesn't access the network.
-The VS Code plugin doesn't access the network unless the nightly channel is selected in the settings.
-In that case, the plugin uses the GitHub API to check for and download updates.
+== Privacy
+
+The LSP server performs no network access in itself, but runs `cargo metadata` which will update or download the crate registry and the source code of the project dependencies.
+If enabled (the default), build scripts and procedural macros can do anything.
+
+The Code extension automatically connects to GitHub to download updated LSP binaries and, if the nightly channel is selected, to perform update checks using the GitHub API. For `rust-analyzer` developers, using `cargo xtask release` uses the same API to put together the release notes.
+
+Any other editor plugins are not under the control of the `rust-analyzer` developers. For any privacy concerns, you should check with their respective developers.
 
 == Features
 
diff --git a/editors/code/package-lock.json b/editors/code/package-lock.json
index 52ffc0f9f..d22c80754 100644
--- a/editors/code/package-lock.json
+++ b/editors/code/package-lock.json
@@ -986,9 +986,9 @@
             }
         },
         "node_modules/css-what": {
-            "version": "5.0.0",
-            "resolved": "https://registry.npmjs.org/css-what/-/css-what-5.0.0.tgz",
-            "integrity": "sha512-qxyKHQvgKwzwDWC/rGbT821eJalfupxYW2qbSJSAtdSTimsr/MlaGONoNLllaUPZWf8QnbcKM/kPVYUQuEKAFA==",
+            "version": "5.0.1",
+            "resolved": "https://registry.npmjs.org/css-what/-/css-what-5.0.1.tgz",
+            "integrity": "sha512-FYDTSHb/7KXsWICVsxdmiExPjCfRC4qRFBdVwv7Ax9hMnvMmEjP9RfxTEZ3qPZGmADDn2vAKSo9UcN1jKVYscg==",
             "dev": true,
             "engines": {
                 "node": ">= 6"
@@ -4345,9 +4345,9 @@
             }
         },
         "css-what": {
-            "version": "5.0.0",
-            "resolved": "https://registry.npmjs.org/css-what/-/css-what-5.0.0.tgz",
-            "integrity": "sha512-qxyKHQvgKwzwDWC/rGbT821eJalfupxYW2qbSJSAtdSTimsr/MlaGONoNLllaUPZWf8QnbcKM/kPVYUQuEKAFA==",
+            "version": "5.0.1",
+            "resolved": "https://registry.npmjs.org/css-what/-/css-what-5.0.1.tgz",
+            "integrity": "sha512-FYDTSHb/7KXsWICVsxdmiExPjCfRC4qRFBdVwv7Ax9hMnvMmEjP9RfxTEZ3qPZGmADDn2vAKSo9UcN1jKVYscg==",
             "dev": true
         },
         "debug": {
diff --git a/editors/code/package.json b/editors/code/package.json
index 43a5cc2b5..666016ae4 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -313,7 +313,7 @@
                 },
                 "rust-analyzer.updates.askBeforeDownload": {
                     "type": "boolean",
-                    "default": true,
+                    "default": false,
                     "description": "Whether to ask for permission before downloading any files from the Internet."
                 },
                 "rust-analyzer.server.path": {
@@ -389,7 +389,7 @@
                     "default": {},
                     "markdownDescription": "Optional settings passed to the debug engine. Example: `{ \"lldb\": { \"terminal\":\"external\"} }`"
                 },
-                "$generated-start": false,
+                "$generated-start": {},
                 "rust-analyzer.assist.importGranularity": {
                     "markdownDescription": "How imports should be grouped into use statements.",
                     "default": "crate",
@@ -418,13 +418,13 @@
                     "type": "string",
                     "enum": [
                         "plain",
-                        "by_self",
-                        "by_crate"
+                        "self",
+                        "crate"
                     ],
                     "enumDescriptions": [
                         "Insert import paths relative to the current module, using up to one `super` prefix if the parent module contains the requested item.",
-                        "Prefix all import paths with `self` if they don't begin with `self`, `super`, `crate` or a crate name.",
-                        "Force import paths to be absolute by always starting them with `crate` or the crate name they refer to."
+                        "Insert import paths relative to the current module, using up to one `super` prefix if the parent module contains the requested item. Prefixes `self` in front of the path if it starts with a module.",
+                        "Force import paths to be absolute by always starting them with `crate` or the extern crate name they come from."
                     ]
                 },
                 "rust-analyzer.assist.importGroup": {
@@ -432,6 +432,11 @@
                     "default": true,
                     "type": "boolean"
                 },
+                "rust-analyzer.assist.allowMergingIntoGlobImports": {
+                    "markdownDescription": "Whether to allow import insertion to merge new imports into single path glob imports like `use std::fmt::*;`.",
+                    "default": true,
+                    "type": "boolean"
+                },
                 "rust-analyzer.callInfo.full": {
                     "markdownDescription": "Show function name and docs in parameter hints.",
                     "default": true,
@@ -447,6 +452,16 @@
                     "default": false,
                     "type": "boolean"
                 },
+                "rust-analyzer.cargo.unsetTest": {
+                    "markdownDescription": "Unsets `#[cfg(test)]` for the specified crates.",
+                    "default": [
+                        "core"
+                    ],
+                    "type": "array",
+                    "items": {
+                        "type": "string"
+                    }
+                },
                 "rust-analyzer.cargo.features": {
                     "markdownDescription": "List of features to activate.",
                     "default": [],
@@ -846,7 +861,7 @@
                         "Search for all symbols kinds"
                     ]
                 },
-                "$generated-end": false
+                "$generated-end": {}
             }
         },
         "problemPatterns": [
diff --git a/editors/code/src/main.ts b/editors/code/src/main.ts
index f58d26215..15f2151ad 100644
--- a/editors/code/src/main.ts
+++ b/editors/code/src/main.ts
@@ -158,7 +158,7 @@ export async function deactivate() {
 }
 
 async function bootstrap(config: Config, state: PersistentState): Promise<string> {
-    await vscode.workspace.fs.createDirectory(config.globalStorageUri);
+    await vscode.workspace.fs.createDirectory(config.globalStorageUri).then();
 
     if (!config.currentExtensionIsNightly) {
         await state.updateNightlyReleaseId(undefined);
@@ -277,11 +277,11 @@ async function patchelf(dest: vscode.Uri): Promise<void> {
                     '';
                 }
             `;
-            const origFile = vscode.Uri.file(dest.path + "-orig");
+            const origFile = vscode.Uri.file(dest.fsPath + "-orig");
             await vscode.workspace.fs.rename(dest, origFile);
             progress.report({ message: "Patching executable", increment: 20 });
             await new Promise((resolve, reject) => {
-                const handle = exec(`nix-build -E - --argstr srcStr '${origFile.path}' -o '${dest.path}'`,
+                const handle = exec(`nix-build -E - --argstr srcStr '${origFile.fsPath}' -o '${dest.fsPath}'`,
                     (err, stdout, stderr) => {
                         if (err != null) {
                             reject(Error(stderr));
@@ -338,14 +338,14 @@ async function getServer(config: Config, state: PersistentState): Promise<string
         await state.updateServerVersion(undefined);
     }
 
-    if (state.serverVersion === config.package.version) return dest.path;
+    if (state.serverVersion === config.package.version) return dest.fsPath;
 
     if (config.askBeforeDownload) {
         const userResponse = await vscode.window.showInformationMessage(
             `Language server version ${config.package.version} for rust-analyzer is not installed.`,
             "Download now"
         );
-        if (userResponse !== "Download now") return dest.path;
+        if (userResponse !== "Download now") return dest.fsPath;
     }
 
     const releaseTag = config.package.releaseTag;
@@ -372,7 +372,7 @@ async function getServer(config: Config, state: PersistentState): Promise<string
     }
 
     await state.updateServerVersion(config.package.version);
-    return dest.path;
+    return dest.fsPath;
 }
 
 function serverPath(config: Config): string | null {
@@ -383,7 +383,7 @@ async function isNixOs(): Promise<boolean> {
     try {
         const contents = (await vscode.workspace.fs.readFile(vscode.Uri.file("/etc/os-release"))).toString();
         return contents.indexOf("ID=nixos") !== -1;
-    } catch (e) {
+    } catch {
         return false;
     }
 }
diff --git a/editors/code/src/net.ts b/editors/code/src/net.ts
index 747c02db9..722dab756 100644
--- a/editors/code/src/net.ts
+++ b/editors/code/src/net.ts
@@ -91,7 +91,7 @@ export async function download(opts: DownloadOpts) {
     // to prevent partially downloaded files when user kills vscode
     // This also avoids overwriting running executables
     const randomHex = crypto.randomBytes(5).toString("hex");
-    const rawDest = path.parse(opts.dest.path);
+    const rawDest = path.parse(opts.dest.fsPath);
     const tempFilePath = vscode.Uri.joinPath(vscode.Uri.file(rawDest.dir), `${rawDest.name}${randomHex}`);
 
     await vscode.window.withProgress(
@@ -116,7 +116,7 @@ export async function download(opts: DownloadOpts) {
         }
     );
 
-    await vscode.workspace.fs.rename(tempFilePath, opts.dest);
+    await vscode.workspace.fs.rename(tempFilePath, opts.dest, { overwrite: true });
 }
 
 async function downloadFile(
@@ -127,17 +127,19 @@ async function downloadFile(
     httpProxy: string | null | undefined,
     onProgress: (readBytes: number, totalBytes: number) => void
 ): Promise<void> {
+    const urlString = url.toString();
+
     const res = await (() => {
         if (httpProxy) {
-            log.debug(`Downloading ${url.path} via proxy: ${httpProxy}`);
-            return fetch(url.path, { agent: new HttpsProxyAgent(httpProxy) });
+            log.debug(`Downloading ${urlString} via proxy: ${httpProxy}`);
+            return fetch(urlString, { agent: new HttpsProxyAgent(httpProxy) });
         }
 
-        return fetch(url.path);
+        return fetch(urlString);
     })();
 
     if (!res.ok) {
-        log.error("Error", res.status, "while downloading file from", url.path);
+        log.error("Error", res.status, "while downloading file from", urlString);
         log.error({ body: await res.text(), headers: res.headers });
 
         throw new Error(`Got response ${res.status} when trying to download a file.`);
@@ -146,7 +148,7 @@ async function downloadFile(
     const totalBytes = Number(res.headers.get('content-length'));
     assert(!Number.isNaN(totalBytes), "Sanity check of content-length protocol");
 
-    log.debug("Downloading file of", totalBytes, "bytes size from", url.path, "to", destFilePath.path);
+    log.debug("Downloading file of", totalBytes, "bytes size from", urlString, "to", destFilePath.fsPath);
 
     let readBytes = 0;
     res.body.on("data", (chunk: Buffer) => {
@@ -154,7 +156,7 @@ async function downloadFile(
         onProgress(readBytes, totalBytes);
     });
 
-    const destFileStream = fs.createWriteStream(destFilePath.path, { mode });
+    const destFileStream = fs.createWriteStream(destFilePath.fsPath, { mode });
     const srcStream = gunzip ? res.body.pipe(zlib.createGunzip()) : res.body;
 
     await pipeline(srcStream, destFileStream);
diff --git a/editors/code/src/toolchain.ts b/editors/code/src/toolchain.ts
index 902d0ddda..355dd76fe 100644
--- a/editors/code/src/toolchain.ts
+++ b/editors/code/src/toolchain.ts
@@ -159,7 +159,7 @@ export const getPathForExecutable = memoize(
             // it is not mentioned in docs and cannot be infered by the type signature...
             const standardPath = vscode.Uri.joinPath(vscode.Uri.file(os.homedir()), ".cargo", "bin", executableName);
 
-            if (isFile(standardPath.path)) return standardPath.path;
+            if (isFileAtUri(standardPath)) return standardPath.fsPath;
         } catch (err) {
             log.error("Failed to read the fs info", err);
         }
@@ -177,9 +177,17 @@ function lookupInPath(exec: string): boolean {
             : [candidate];
     });
 
-    return candidates.some(isFile);
+    return candidates.some(isFileAtPath);
 }
 
-async function isFile(path: string): Promise<boolean> {
-    return ((await vscode.workspace.fs.stat(vscode.Uri.file(path))).type & vscode.FileType.File) !== 0;
+async function isFileAtPath(path: string): Promise<boolean> {
+    return isFileAtUri(vscode.Uri.file(path));
+}
+
+async function isFileAtUri(uri: vscode.Uri): Promise<boolean> {
+    try {
+        return ((await vscode.workspace.fs.stat(uri)).type & vscode.FileType.File) !== 0;
+    } catch {
+        return false;
+    }
 }
diff --git a/xtask/src/dist.rs b/xtask/src/dist.rs
index 3a67294c5..c7363688a 100644
--- a/xtask/src/dist.rs
+++ b/xtask/src/dist.rs
@@ -45,8 +45,8 @@ fn dist_client(version: &str, release_tag: &str) -> Result<()> {
     patch
         .replace(r#""version": "0.4.0-dev""#, &format!(r#""version": "{}""#, version))
         .replace(r#""releaseTag": null"#, &format!(r#""releaseTag": "{}""#, release_tag))
-        .replace(r#""$generated-start": false,"#, "")
-        .replace(",\n                \"$generated-end\": false", "");
+        .replace(r#""$generated-start": {},"#, "")
+        .replace(",\n                \"$generated-end\": {}", "");
 
     if nightly {
         patch.replace(
diff --git a/xtask/src/install.rs b/xtask/src/install.rs
index 7e2dccdfe..64ab12b42 100644
--- a/xtask/src/install.rs
+++ b/xtask/src/install.rs
@@ -8,7 +8,7 @@ use xshell::{cmd, pushd};
 use crate::flags;
 
 // Latest stable, feel free to send a PR if this lags behind.
-const REQUIRED_RUST_VERSION: u32 = 52;
+const REQUIRED_RUST_VERSION: u32 = 53;
 
 impl flags::Install {
     pub(crate) fn run(self) -> Result<()> {
diff --git a/xtask/src/tidy.rs b/xtask/src/tidy.rs
index f2ba8efef..a9d434e20 100644
--- a/xtask/src/tidy.rs
+++ b/xtask/src/tidy.rs
@@ -89,6 +89,7 @@ fn rust_files_are_tidy() {
         let text = read_file(&path).unwrap();
         check_todo(&path, &text);
         check_dbg(&path, &text);
+        check_test_attrs(&path, &text);
         check_trailing_ws(&path, &text);
         deny_clippy(&path, &text);
         tidy_docs.visit(&path, &text);
@@ -334,13 +335,43 @@ fn check_dbg(path: &Path, text: &str) {
     }
 }
 
+fn check_test_attrs(path: &Path, text: &str) {
+    let ignore_rule =
+        "https://github.com/rust-analyzer/rust-analyzer/blob/master/docs/dev/style.md#ignore";
+    let need_ignore: &[&str] = &[
+        // Special case to run `#[ignore]` tests
+        "ide/src/runnables.rs",
+        // A legit test which needs to be ignored, as it takes too long to run
+        // :(
+        "hir_def/src/nameres/collector.rs",
+        // Obviously needs ignore.
+        "ide_assists/src/handlers/toggle_ignore.rs",
+        // See above.
+        "ide_assists/src/tests/generated.rs",
+    ];
+    if text.contains("#[ignore") && !need_ignore.iter().any(|p| path.ends_with(p)) {
+        panic!("\ndon't `#[ignore]` tests, see:\n\n    {}\n\n   {}\n", ignore_rule, path.display(),)
+    }
+
+    let panic_rule =
+        "https://github.com/rust-analyzer/rust-analyzer/blob/master/docs/dev/style.md#should_panic";
+    let need_panic: &[&str] = &["test_utils/src/fixture.rs"];
+    if text.contains("#[should_panic") && !need_panic.iter().any(|p| path.ends_with(p)) {
+        panic!(
+            "\ndon't add `#[should_panic]` tests, see:\n\n    {}\n\n   {}\n",
+            panic_rule,
+            path.display(),
+        )
+    }
+}
+
 fn check_trailing_ws(path: &Path, text: &str) {
     if is_exclude_dir(path, &["test_data"]) {
         return;
     }
     for (line_number, line) in text.lines().enumerate() {
         if line.chars().last().map(char::is_whitespace) == Some(true) {
-            panic!("Trailing whitespace in {} at line {}", path.display(), line_number)
+            panic!("Trailing whitespace in {} at line {}", path.display(), line_number + 1)
         }
     }
 }