247 files changed, 8558 insertions, 8462 deletions

diff --git a/crates/base_db/src/fixture.rs b/crates/base_db/src/fixture.rs
index 69ceba735..d56b20b83 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();
@@ -158,6 +166,31 @@ 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);
@@ -190,7 +223,7 @@ impl From<Fixture> for FileMeta {
             edition: f
                 .edition
                 .as_ref()
-                .map_or(Edition::Edition2018, |v| Edition::from_str(&v).unwrap()),
+                .map_or(Edition::Edition2018, |v| Edition::from_str(v).unwrap()),
             env: f.env.into_iter().collect(),
             introduce_new_source_root: f.introduce_new_source_root,
         }
diff --git a/crates/base_db/src/lib.rs b/crates/base_db/src/lib.rs
index 54baa3a63..d26f8f180 100644
--- a/crates/base_db/src/lib.rs
+++ b/crates/base_db/src/lib.rs
@@ -42,7 +42,7 @@ pub struct FilePosition {
     pub offset: TextSize,
 }
 
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
 pub struct FileRange {
     pub file_id: FileId,
     pub range: TextRange,
diff --git a/crates/cfg/src/cfg_expr.rs b/crates/cfg/src/cfg_expr.rs
index 069fc01d0..8a1a51e6e 100644
--- a/crates/cfg/src/cfg_expr.rs
+++ b/crates/cfg/src/cfg_expr.rs
@@ -1,6 +1,6 @@
 //! The condition expression used in `#[cfg(..)]` attributes.
 //!
-//! See: https://doc.rust-lang.org/reference/conditional-compilation.html#conditional-compilation
+//! See: <https://doc.rust-lang.org/reference/conditional-compilation.html#conditional-compilation>
 
 use std::{fmt, slice::Iter as SliceIter};
 
diff --git a/crates/cfg/src/lib.rs b/crates/cfg/src/lib.rs
index 59fd38880..03b8dd767 100644
--- a/crates/cfg/src/lib.rs
+++ b/crates/cfg/src/lib.rs
@@ -22,7 +22,7 @@ pub use dnf::DnfExpr;
 /// `foo` and `bar` are both enabled. And here, we store key-value options as a set of tuple
 /// of key and value in `key_values`.
 ///
-/// See: https://doc.rust-lang.org/reference/conditional-compilation.html#set-configuration-options
+/// See: <https://doc.rust-lang.org/reference/conditional-compilation.html#set-configuration-options>
 #[derive(Debug, Clone, PartialEq, Eq, Default)]
 pub struct CfgOptions {
     enabled: FxHashSet<CfgAtom>,
diff --git a/crates/hir/Cargo.toml b/crates/hir/Cargo.toml
index 560b15238..7c148fd40 100644
--- a/crates/hir/Cargo.toml
+++ b/crates/hir/Cargo.toml
@@ -16,6 +16,7 @@ either = "1.5.3"
 arrayvec = "0.7"
 itertools = "0.10.0"
 smallvec = "1.4.0"
+once_cell = "1"
 
 stdx = { path = "../stdx", version = "0.0.0" }
 syntax = { path = "../syntax", version = "0.0.0" }
diff --git a/crates/hir/src/diagnostics.rs b/crates/hir/src/diagnostics.rs
index 2cdbd172a..b4c505898 100644
--- a/crates/hir/src/diagnostics.rs
+++ b/crates/hir/src/diagnostics.rs
@@ -3,251 +3,152 @@
 //!
 //! This probably isn't the best way to do this -- ideally, diagnistics should
 //! be expressed in terms of hir types themselves.
-use std::any::Any;
-
-use cfg::{CfgExpr, CfgOptions, DnfExpr};
+use cfg::{CfgExpr, CfgOptions};
+use either::Either;
 use hir_def::path::ModPath;
-use hir_expand::{HirFileId, InFile};
-use stdx::format_to;
+use hir_expand::{name::Name, HirFileId, InFile};
 use syntax::{ast, AstPtr, SyntaxNodePtr, TextRange};
 
-pub use hir_ty::{
-    diagnostics::{
-        IncorrectCase, MismatchedArgCount, MissingFields, MissingMatchArms,
-        MissingOkOrSomeInTailExpr, NoSuchField, RemoveThisSemicolon,
-        ReplaceFilterMapNextWithFindMap,
-    },
-    diagnostics_sink::{Diagnostic, DiagnosticCode, DiagnosticSink, DiagnosticSinkBuilder},
-};
-
-// Diagnostic: unresolved-module
-//
-// This diagnostic is triggered if rust-analyzer is unable to discover referred module.
+macro_rules! diagnostics {
+    ($($diag:ident,)*) => {
+        pub enum AnyDiagnostic {$(
+            $diag(Box<$diag>),
+        )*}
+
+        $(
+            impl From<$diag> for AnyDiagnostic {
+                fn from(d: $diag) -> AnyDiagnostic {
+                    AnyDiagnostic::$diag(Box::new(d))
+                }
+            }
+        )*
+    };
+}
+
+diagnostics![
+    BreakOutsideOfLoop,
+    InactiveCode,
+    IncorrectCase,
+    MacroError,
+    MismatchedArgCount,
+    MissingFields,
+    MissingMatchArms,
+    MissingOkOrSomeInTailExpr,
+    MissingUnsafe,
+    NoSuchField,
+    RemoveThisSemicolon,
+    ReplaceFilterMapNextWithFindMap,
+    UnimplementedBuiltinMacro,
+    UnresolvedExternCrate,
+    UnresolvedImport,
+    UnresolvedMacroCall,
+    UnresolvedModule,
+    UnresolvedProcMacro,
+];
+
 #[derive(Debug)]
 pub struct UnresolvedModule {
-    pub file: HirFileId,
-    pub decl: AstPtr<ast::Module>,
+    pub decl: InFile<AstPtr<ast::Module>>,
     pub candidate: String,
 }
 
-impl Diagnostic for UnresolvedModule {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("unresolved-module")
-    }
-    fn message(&self) -> String {
-        "unresolved module".to_string()
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile::new(self.file, self.decl.clone().into())
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-}
-
-// Diagnostic: unresolved-extern-crate
-//
-// This diagnostic is triggered if rust-analyzer is unable to discover referred extern crate.
 #[derive(Debug)]
 pub struct UnresolvedExternCrate {
-    pub file: HirFileId,
-    pub item: AstPtr<ast::ExternCrate>,
-}
-
-impl Diagnostic for UnresolvedExternCrate {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("unresolved-extern-crate")
-    }
-    fn message(&self) -> String {
-        "unresolved extern crate".to_string()
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile::new(self.file, self.item.clone().into())
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
+    pub decl: InFile<AstPtr<ast::ExternCrate>>,
 }
 
 #[derive(Debug)]
 pub struct UnresolvedImport {
-    pub file: HirFileId,
-    pub node: AstPtr<ast::UseTree>,
-}
-
-impl Diagnostic for UnresolvedImport {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("unresolved-import")
-    }
-    fn message(&self) -> String {
-        "unresolved import".to_string()
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile::new(self.file, self.node.clone().into())
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-    fn is_experimental(&self) -> bool {
-        // This currently results in false positives in the following cases:
-        // - `cfg_if!`-generated code in libstd (we don't load the sysroot correctly)
-        // - `core::arch` (we don't handle `#[path = "../<path>"]` correctly)
-        // - proc macros and/or proc macro generated code
-        true
-    }
-}
-
-// 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 decl: InFile<AstPtr<ast::UseTree>>,
+}
+
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub struct UnresolvedMacroCall {
-    pub file: HirFileId,
-    pub node: AstPtr<ast::MacroCall>,
+    pub macro_call: InFile<AstPtr<ast::MacroCall>>,
     pub path: ModPath,
 }
 
-impl Diagnostic for UnresolvedMacroCall {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("unresolved-macro-call")
-    }
-    fn message(&self) -> String {
-        format!("unresolved macro `{}!`", self.path)
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile::new(self.file, self.node.clone().into())
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-    fn is_experimental(&self) -> bool {
-        true
-    }
-}
-
-// Diagnostic: inactive-code
-//
-// This diagnostic is shown for code with inactive `#[cfg]` attributes.
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub struct InactiveCode {
-    pub file: HirFileId,
-    pub node: SyntaxNodePtr,
+    pub node: InFile<SyntaxNodePtr>,
     pub cfg: CfgExpr,
     pub opts: CfgOptions,
 }
 
-impl Diagnostic for InactiveCode {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("inactive-code")
-    }
-    fn message(&self) -> String {
-        let inactive = DnfExpr::new(self.cfg.clone()).why_inactive(&self.opts);
-        let mut buf = "code is inactive due to #[cfg] directives".to_string();
-
-        if let Some(inactive) = inactive {
-            format_to!(buf, ": {}", inactive);
-        }
-
-        buf
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile::new(self.file, self.node.clone())
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-}
-
-// Diagnostic: unresolved-proc-macro
-//
-// This diagnostic is shown when a procedural macro can not be found. This usually means that
-// procedural macro support is simply disabled (and hence is only a weak hint instead of an error),
-// but can also indicate project setup problems.
-//
-// 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`).
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub struct UnresolvedProcMacro {
-    pub file: HirFileId,
-    pub node: SyntaxNodePtr,
+    pub node: InFile<SyntaxNodePtr>,
     /// If the diagnostic can be pinpointed more accurately than via `node`, this is the `TextRange`
     /// to use instead.
     pub precise_location: Option<TextRange>,
     pub macro_name: Option<String>,
 }
 
-impl Diagnostic for UnresolvedProcMacro {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("unresolved-proc-macro")
-    }
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct MacroError {
+    pub node: InFile<SyntaxNodePtr>,
+    pub message: String,
+}
 
-    fn message(&self) -> String {
-        match &self.macro_name {
-            Some(name) => format!("proc macro `{}` not expanded", name),
-            None => "proc macro not expanded".to_string(),
-        }
-    }
+#[derive(Debug)]
+pub struct UnimplementedBuiltinMacro {
+    pub node: InFile<SyntaxNodePtr>,
+}
 
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile::new(self.file, self.node.clone())
-    }
+#[derive(Debug)]
+pub struct NoSuchField {
+    pub field: InFile<AstPtr<ast::RecordExprField>>,
+}
 
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
+#[derive(Debug)]
+pub struct BreakOutsideOfLoop {
+    pub expr: InFile<AstPtr<ast::Expr>>,
 }
 
-// Diagnostic: macro-error
-//
-// This diagnostic is shown for macro expansion errors.
-#[derive(Debug, Clone, Eq, PartialEq)]
-pub struct MacroError {
-    pub file: HirFileId,
-    pub node: SyntaxNodePtr,
-    pub message: String,
+#[derive(Debug)]
+pub struct MissingUnsafe {
+    pub expr: InFile<AstPtr<ast::Expr>>,
 }
 
-impl Diagnostic for MacroError {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("macro-error")
-    }
-    fn message(&self) -> String {
-        self.message.clone()
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile::new(self.file, self.node.clone())
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-    fn is_experimental(&self) -> bool {
-        // Newly added and not very well-tested, might contain false positives.
-        true
-    }
+#[derive(Debug)]
+pub struct MissingFields {
+    pub file: HirFileId,
+    pub field_list_parent: Either<AstPtr<ast::RecordExpr>, AstPtr<ast::RecordPat>>,
+    pub field_list_parent_path: Option<AstPtr<ast::Path>>,
+    pub missed_fields: Vec<Name>,
 }
 
 #[derive(Debug)]
-pub struct UnimplementedBuiltinMacro {
+pub struct ReplaceFilterMapNextWithFindMap {
     pub file: HirFileId,
-    pub node: SyntaxNodePtr,
+    /// This expression is the whole method chain up to and including `.filter_map(..).next()`.
+    pub next_expr: AstPtr<ast::Expr>,
 }
 
-impl Diagnostic for UnimplementedBuiltinMacro {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("unimplemented-builtin-macro")
-    }
+#[derive(Debug)]
+pub struct MismatchedArgCount {
+    pub call_expr: InFile<AstPtr<ast::Expr>>,
+    pub expected: usize,
+    pub found: usize,
+}
 
-    fn message(&self) -> String {
-        "unimplemented built-in macro".to_string()
-    }
+#[derive(Debug)]
+pub struct RemoveThisSemicolon {
+    pub expr: InFile<AstPtr<ast::Expr>>,
+}
 
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile::new(self.file, self.node.clone())
-    }
+#[derive(Debug)]
+pub struct MissingOkOrSomeInTailExpr {
+    pub expr: InFile<AstPtr<ast::Expr>>,
+    // `Some` or `Ok` depending on whether the return type is Result or Option
+    pub required: String,
+}
 
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
+#[derive(Debug)]
+pub struct MissingMatchArms {
+    pub file: HirFileId,
+    pub match_expr: AstPtr<ast::Expr>,
+    pub arms: AstPtr<ast::MatchArmList>,
 }
+
+pub use hir_ty::diagnostics::IncorrectCase;
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 0bb3767c1..b7eabaabb 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -15,7 +15,7 @@
 //!
 //! `hir` is what insulates the "we don't know how to actually write an incremental compiler"
 //! from the ide with completions, hovers, etc. It is a (soft, internal) boundary:
-//! https://www.tedinski.com/2018/02/06/system-boundaries.html.
+//! <https://www.tedinski.com/2018/02/06/system-boundaries.html>.
 
 #![recursion_limit = "512"]
 
@@ -35,14 +35,10 @@ use std::{iter, sync::Arc};
 
 use arrayvec::ArrayVec;
 use base_db::{CrateDisplayName, CrateId, Edition, FileId};
-use diagnostics::{
-    InactiveCode, MacroError, UnimplementedBuiltinMacro, UnresolvedExternCrate, UnresolvedImport,
-    UnresolvedMacroCall, UnresolvedModule, UnresolvedProcMacro,
-};
 use either::Either;
 use hir_def::{
     adt::{ReprKind, VariantData},
-    body::BodyDiagnostic,
+    body::{BodyDiagnostic, SyntheticSyntax},
     expr::{BindingAnnotation, LabelId, Pat, PatId},
     item_tree::ItemTreeNode,
     lang_item::LangItemTarget,
@@ -60,8 +56,8 @@ use hir_ty::{
     autoderef,
     consteval::ConstExt,
     could_unify,
-    diagnostics_sink::DiagnosticSink,
-    method_resolution::{self, def_crates, TyFingerprint},
+    diagnostics::BodyValidationDiagnostic,
+    method_resolution::{self, TyFingerprint},
     primitive::UintTy,
     subst_prefix,
     traits::FnTrait,
@@ -72,6 +68,7 @@ use hir_ty::{
 };
 use itertools::Itertools;
 use nameres::diagnostics::DefDiagnosticKind;
+use once_cell::unsync::Lazy;
 use rustc_hash::FxHashSet;
 use stdx::{format_to, impl_from};
 use syntax::{
@@ -84,6 +81,13 @@ use crate::db::{DefDatabase, HirDatabase};
 
 pub use crate::{
     attrs::{HasAttrs, Namespace},
+    diagnostics::{
+        AnyDiagnostic, BreakOutsideOfLoop, InactiveCode, IncorrectCase, MacroError,
+        MismatchedArgCount, MissingFields, MissingMatchArms, MissingOkOrSomeInTailExpr,
+        MissingUnsafe, NoSuchField, RemoveThisSemicolon, ReplaceFilterMapNextWithFindMap,
+        UnimplementedBuiltinMacro, UnresolvedExternCrate, UnresolvedImport, UnresolvedMacroCall,
+        UnresolvedModule, UnresolvedProcMacro,
+    },
     has_source::HasSource,
     semantics::{PathResolution, Semantics, SemanticsScope},
 };
@@ -332,7 +336,7 @@ impl ModuleDef {
         }
     }
 
-    pub fn diagnostics(self, db: &dyn HirDatabase, sink: &mut DiagnosticSink) {
+    pub fn diagnostics(self, db: &dyn HirDatabase) -> Vec<AnyDiagnostic> {
         let id = match self {
             ModuleDef::Adt(it) => match it {
                 Adt::Struct(it) => it.id.into(),
@@ -345,15 +349,19 @@ impl ModuleDef {
             ModuleDef::Module(it) => it.id.into(),
             ModuleDef::Const(it) => it.id.into(),
             ModuleDef::Static(it) => it.id.into(),
-            _ => return,
+            _ => return Vec::new(),
         };
 
         let module = match self.module(db) {
             Some(it) => it,
-            None => return,
+            None => return Vec::new(),
         };
 
-        hir_ty::diagnostics::validate_module_item(db, module.id.krate(), id, sink)
+        let mut acc = Vec::new();
+        for diag in hir_ty::diagnostics::validate_module_item(db, module.id.krate(), id) {
+            acc.push(diag.into())
+        }
+        acc
     }
 }
 
@@ -442,10 +450,10 @@ impl Module {
     }
 
     pub fn visibility_of(self, db: &dyn HirDatabase, def: &ModuleDef) -> Option<Visibility> {
-        self.id.def_map(db.upcast())[self.id.local_id].scope.visibility_of(def.clone().into())
+        self.id.def_map(db.upcast())[self.id.local_id].scope.visibility_of((*def).into())
     }
 
-    pub fn diagnostics(self, db: &dyn HirDatabase, sink: &mut DiagnosticSink) {
+    pub fn diagnostics(self, db: &dyn HirDatabase, acc: &mut Vec<AnyDiagnostic>) {
         let _p = profile::span("Module::diagnostics").detail(|| {
             format!("{:?}", self.name(db).map_or("<unknown>".into(), |name| name.to_string()))
         });
@@ -458,18 +466,22 @@ impl Module {
             match &diag.kind {
                 DefDiagnosticKind::UnresolvedModule { ast: declaration, candidate } => {
                     let decl = declaration.to_node(db.upcast());
-                    sink.push(UnresolvedModule {
-                        file: declaration.file_id,
-                        decl: AstPtr::new(&decl),
-                        candidate: candidate.clone(),
-                    })
+                    acc.push(
+                        UnresolvedModule {
+                            decl: InFile::new(declaration.file_id, AstPtr::new(&decl)),
+                            candidate: candidate.clone(),
+                        }
+                        .into(),
+                    )
                 }
                 DefDiagnosticKind::UnresolvedExternCrate { ast } => {
                     let item = ast.to_node(db.upcast());
-                    sink.push(UnresolvedExternCrate {
-                        file: ast.file_id,
-                        item: AstPtr::new(&item),
-                    });
+                    acc.push(
+                        UnresolvedExternCrate {
+                            decl: InFile::new(ast.file_id, AstPtr::new(&item)),
+                        }
+                        .into(),
+                    );
                 }
 
                 DefDiagnosticKind::UnresolvedImport { id, index } => {
@@ -478,25 +490,30 @@ impl Module {
                     let import = &item_tree[id.value];
 
                     let use_tree = import.use_tree_to_ast(db.upcast(), file_id, *index);
-                    sink.push(UnresolvedImport { file: file_id, node: AstPtr::new(&use_tree) });
+                    acc.push(
+                        UnresolvedImport { decl: InFile::new(file_id, AstPtr::new(&use_tree)) }
+                            .into(),
+                    );
                 }
 
                 DefDiagnosticKind::UnconfiguredCode { ast, cfg, opts } => {
                     let item = ast.to_node(db.upcast());
-                    sink.push(InactiveCode {
-                        file: ast.file_id,
-                        node: AstPtr::new(&item).into(),
-                        cfg: cfg.clone(),
-                        opts: opts.clone(),
-                    });
+                    acc.push(
+                        InactiveCode {
+                            node: ast.with_value(AstPtr::new(&item).into()),
+                            cfg: cfg.clone(),
+                            opts: opts.clone(),
+                        }
+                        .into(),
+                    );
                 }
 
                 DefDiagnosticKind::UnresolvedProcMacro { ast } => {
                     let mut precise_location = None;
-                    let (file, ast, name) = match ast {
+                    let (node, name) = match ast {
                         MacroCallKind::FnLike { ast_id, .. } => {
                             let node = ast_id.to_node(db.upcast());
-                            (ast_id.file_id, SyntaxNodePtr::from(AstPtr::new(&node)), None)
+                            (ast_id.with_value(SyntaxNodePtr::from(AstPtr::new(&node))), None)
                         }
                         MacroCallKind::Derive { ast_id, derive_name, .. } => {
                             let node = ast_id.to_node(db.upcast());
@@ -529,8 +546,7 @@ impl Module {
                             }
 
                             (
-                                ast_id.file_id,
-                                SyntaxNodePtr::from(AstPtr::new(&node)),
+                                ast_id.with_value(SyntaxNodePtr::from(AstPtr::new(&node))),
                                 Some(derive_name.clone()),
                             )
                         }
@@ -541,73 +557,73 @@ impl Module {
                                     || panic!("cannot find attribute #{}", invoc_attr_index),
                                 );
                             (
-                                ast_id.file_id,
-                                SyntaxNodePtr::from(AstPtr::new(&attr)),
+                                ast_id.with_value(SyntaxNodePtr::from(AstPtr::new(&attr))),
                                 Some(attr_name.clone()),
                             )
                         }
                     };
-                    sink.push(UnresolvedProcMacro {
-                        file,
-                        node: ast,
-                        precise_location,
-                        macro_name: name,
-                    });
+                    acc.push(
+                        UnresolvedProcMacro { node, precise_location, macro_name: name }.into(),
+                    );
                 }
 
                 DefDiagnosticKind::UnresolvedMacroCall { ast, path } => {
                     let node = ast.to_node(db.upcast());
-                    sink.push(UnresolvedMacroCall {
-                        file: ast.file_id,
-                        node: AstPtr::new(&node),
-                        path: path.clone(),
-                    });
+                    acc.push(
+                        UnresolvedMacroCall {
+                            macro_call: InFile::new(ast.file_id, AstPtr::new(&node)),
+                            path: path.clone(),
+                        }
+                        .into(),
+                    );
                 }
 
                 DefDiagnosticKind::MacroError { ast, message } => {
-                    let (file, ast) = match ast {
+                    let node = match ast {
                         MacroCallKind::FnLike { ast_id, .. } => {
                             let node = ast_id.to_node(db.upcast());
-                            (ast_id.file_id, SyntaxNodePtr::from(AstPtr::new(&node)))
+                            ast_id.with_value(SyntaxNodePtr::from(AstPtr::new(&node)))
                         }
                         MacroCallKind::Derive { ast_id, .. }
                         | MacroCallKind::Attr { ast_id, .. } => {
                             // FIXME: point to the attribute instead, this creates very large diagnostics
                             let node = ast_id.to_node(db.upcast());
-                            (ast_id.file_id, SyntaxNodePtr::from(AstPtr::new(&node)))
+                            ast_id.with_value(SyntaxNodePtr::from(AstPtr::new(&node)))
                         }
                     };
-                    sink.push(MacroError { file, node: ast, message: message.clone() });
+                    acc.push(MacroError { node, message: message.clone() }.into());
                 }
 
                 DefDiagnosticKind::UnimplementedBuiltinMacro { ast } => {
                     let node = ast.to_node(db.upcast());
                     // Must have a name, otherwise we wouldn't emit it.
                     let name = node.name().expect("unimplemented builtin macro with no name");
-                    let ptr = SyntaxNodePtr::from(AstPtr::new(&name));
-                    sink.push(UnimplementedBuiltinMacro { file: ast.file_id, node: ptr });
+                    acc.push(
+                        UnimplementedBuiltinMacro {
+                            node: ast.with_value(SyntaxNodePtr::from(AstPtr::new(&name))),
+                        }
+                        .into(),
+                    );
                 }
             }
         }
         for decl in self.declarations(db) {
             match decl {
-                crate::ModuleDef::Function(f) => f.diagnostics(db, sink),
-                crate::ModuleDef::Module(m) => {
+                ModuleDef::Function(f) => f.diagnostics(db, acc),
+                ModuleDef::Module(m) => {
                     // Only add diagnostics from inline modules
                     if def_map[m.id.local_id].origin.is_inline() {
-                        m.diagnostics(db, sink)
+                        m.diagnostics(db, acc)
                     }
                 }
-                _ => {
-                    decl.diagnostics(db, sink);
-                }
+                _ => acc.extend(decl.diagnostics(db)),
             }
         }
 
         for impl_def in self.impl_defs(db) {
             for item in impl_def.items(db) {
                 if let AssocItem::Function(f) = item {
-                    f.diagnostics(db, sink);
+                    f.diagnostics(db, acc);
                 }
             }
         }
@@ -1009,41 +1025,191 @@ impl Function {
         db.function_data(self.id).is_async()
     }
 
-    pub fn diagnostics(self, db: &dyn HirDatabase, sink: &mut DiagnosticSink) {
+    pub fn diagnostics(self, db: &dyn HirDatabase, acc: &mut Vec<AnyDiagnostic>) {
         let krate = self.module(db).id.krate();
 
         let source_map = db.body_with_source_map(self.id.into()).1;
         for diag in source_map.diagnostics() {
             match diag {
-                BodyDiagnostic::InactiveCode { node, cfg, opts } => sink.push(InactiveCode {
-                    file: node.file_id,
-                    node: node.value.clone(),
-                    cfg: cfg.clone(),
-                    opts: opts.clone(),
-                }),
-                BodyDiagnostic::MacroError { node, message } => sink.push(MacroError {
-                    file: node.file_id,
-                    node: node.value.clone().into(),
-                    message: message.to_string(),
-                }),
-                BodyDiagnostic::UnresolvedProcMacro { node } => sink.push(UnresolvedProcMacro {
-                    file: node.file_id,
-                    node: node.value.clone().into(),
-                    precise_location: None,
-                    macro_name: None,
-                }),
-                BodyDiagnostic::UnresolvedMacroCall { node, path } => {
-                    sink.push(UnresolvedMacroCall {
-                        file: node.file_id,
-                        node: node.value.clone(),
-                        path: path.clone(),
-                    })
+                BodyDiagnostic::InactiveCode { node, cfg, opts } => acc.push(
+                    InactiveCode { node: node.clone(), cfg: cfg.clone(), opts: opts.clone() }
+                        .into(),
+                ),
+                BodyDiagnostic::MacroError { node, message } => acc.push(
+                    MacroError {
+                        node: node.clone().map(|it| it.into()),
+                        message: message.to_string(),
+                    }
+                    .into(),
+                ),
+                BodyDiagnostic::UnresolvedProcMacro { node } => acc.push(
+                    UnresolvedProcMacro {
+                        node: node.clone().map(|it| it.into()),
+                        precise_location: None,
+                        macro_name: None,
+                    }
+                    .into(),
+                ),
+                BodyDiagnostic::UnresolvedMacroCall { node, path } => acc.push(
+                    UnresolvedMacroCall { macro_call: node.clone(), path: path.clone() }.into(),
+                ),
+            }
+        }
+
+        let infer = db.infer(self.id.into());
+        let source_map = Lazy::new(|| db.body_with_source_map(self.id.into()).1);
+        for d in &infer.diagnostics {
+            match d {
+                hir_ty::InferenceDiagnostic::NoSuchField { expr } => {
+                    let field = source_map.field_syntax(*expr);
+                    acc.push(NoSuchField { field }.into())
+                }
+                hir_ty::InferenceDiagnostic::BreakOutsideOfLoop { expr } => {
+                    let expr = source_map
+                        .expr_syntax(*expr)
+                        .expect("break outside of loop in synthetic syntax");
+                    acc.push(BreakOutsideOfLoop { expr }.into())
                 }
             }
         }
 
-        hir_ty::diagnostics::validate_module_item(db, krate, self.id.into(), sink);
-        hir_ty::diagnostics::validate_body(db, self.id.into(), sink);
+        for expr in hir_ty::diagnostics::missing_unsafe(db, self.id.into()) {
+            match source_map.expr_syntax(expr) {
+                Ok(expr) => acc.push(MissingUnsafe { expr }.into()),
+                Err(SyntheticSyntax) => {
+                    // FIXME: Here and eslwhere in this file, the `expr` was
+                    // desugared, report or assert that this doesn't happen.
+                }
+            }
+        }
+
+        for diagnostic in BodyValidationDiagnostic::collect(db, self.id.into()) {
+            match diagnostic {
+                BodyValidationDiagnostic::RecordMissingFields {
+                    record,
+                    variant,
+                    missed_fields,
+                } => {
+                    let variant_data = variant.variant_data(db.upcast());
+                    let missed_fields = missed_fields
+                        .into_iter()
+                        .map(|idx| variant_data.fields()[idx].name.clone())
+                        .collect();
+
+                    match record {
+                        Either::Left(record_expr) => match source_map.expr_syntax(record_expr) {
+                            Ok(source_ptr) => {
+                                let root = source_ptr.file_syntax(db.upcast());
+                                if let ast::Expr::RecordExpr(record_expr) =
+                                    &source_ptr.value.to_node(&root)
+                                {
+                                    if let Some(_) = record_expr.record_expr_field_list() {
+                                        acc.push(
+                                            MissingFields {
+                                                file: source_ptr.file_id,
+                                                field_list_parent: Either::Left(AstPtr::new(
+                                                    record_expr,
+                                                )),
+                                                field_list_parent_path: record_expr
+                                                    .path()
+                                                    .map(|path| AstPtr::new(&path)),
+                                                missed_fields,
+                                            }
+                                            .into(),
+                                        )
+                                    }
+                                }
+                            }
+                            Err(SyntheticSyntax) => (),
+                        },
+                        Either::Right(record_pat) => match source_map.pat_syntax(record_pat) {
+                            Ok(source_ptr) => {
+                                if let Some(expr) = source_ptr.value.as_ref().left() {
+                                    let root = source_ptr.file_syntax(db.upcast());
+                                    if let ast::Pat::RecordPat(record_pat) = expr.to_node(&root) {
+                                        if let Some(_) = record_pat.record_pat_field_list() {
+                                            acc.push(
+                                                MissingFields {
+                                                    file: source_ptr.file_id,
+                                                    field_list_parent: Either::Right(AstPtr::new(
+                                                        &record_pat,
+                                                    )),
+                                                    field_list_parent_path: record_pat
+                                                        .path()
+                                                        .map(|path| AstPtr::new(&path)),
+                                                    missed_fields,
+                                                }
+                                                .into(),
+                                            )
+                                        }
+                                    }
+                                }
+                            }
+                            Err(SyntheticSyntax) => (),
+                        },
+                    }
+                }
+                BodyValidationDiagnostic::ReplaceFilterMapNextWithFindMap { method_call_expr } => {
+                    if let Ok(next_source_ptr) = source_map.expr_syntax(method_call_expr) {
+                        acc.push(
+                            ReplaceFilterMapNextWithFindMap {
+                                file: next_source_ptr.file_id,
+                                next_expr: next_source_ptr.value,
+                            }
+                            .into(),
+                        );
+                    }
+                }
+                BodyValidationDiagnostic::MismatchedArgCount { call_expr, expected, found } => {
+                    match source_map.expr_syntax(call_expr) {
+                        Ok(source_ptr) => acc.push(
+                            MismatchedArgCount { call_expr: source_ptr, expected, found }.into(),
+                        ),
+                        Err(SyntheticSyntax) => (),
+                    }
+                }
+                BodyValidationDiagnostic::RemoveThisSemicolon { expr } => {
+                    match source_map.expr_syntax(expr) {
+                        Ok(expr) => acc.push(RemoveThisSemicolon { expr }.into()),
+                        Err(SyntheticSyntax) => (),
+                    }
+                }
+                BodyValidationDiagnostic::MissingOkOrSomeInTailExpr { expr, required } => {
+                    match source_map.expr_syntax(expr) {
+                        Ok(expr) => acc.push(MissingOkOrSomeInTailExpr { expr, required }.into()),
+                        Err(SyntheticSyntax) => (),
+                    }
+                }
+                BodyValidationDiagnostic::MissingMatchArms { match_expr } => {
+                    match source_map.expr_syntax(match_expr) {
+                        Ok(source_ptr) => {
+                            let root = source_ptr.file_syntax(db.upcast());
+                            if let ast::Expr::MatchExpr(match_expr) =
+                                &source_ptr.value.to_node(&root)
+                            {
+                                if let (Some(match_expr), Some(arms)) =
+                                    (match_expr.expr(), match_expr.match_arm_list())
+                                {
+                                    acc.push(
+                                        MissingMatchArms {
+                                            file: source_ptr.file_id,
+                                            match_expr: AstPtr::new(&match_expr),
+                                            arms: AstPtr::new(&arms),
+                                        }
+                                        .into(),
+                                    )
+                                }
+                            }
+                        }
+                        Err(SyntheticSyntax) => (),
+                    }
+                }
+            }
+        }
+
+        for diag in hir_ty::diagnostics::validate_module_item(db, krate, self.id.into()) {
+            acc.push(diag.into())
+        }
     }
 
     /// Whether this function declaration has a definition.
@@ -1762,7 +1928,7 @@ impl Impl {
     }
 
     pub fn all_for_type(db: &dyn HirDatabase, Type { krate, ty, .. }: Type) -> Vec<Impl> {
-        let def_crates = match def_crates(db, &ty, krate) {
+        let def_crates = match method_resolution::def_crates(db, &ty, krate) {
             Some(def_crates) => def_crates,
             None => return Vec::new(),
         };
@@ -2168,7 +2334,7 @@ impl Type {
         krate: Crate,
         mut callback: impl FnMut(AssocItem) -> Option<T>,
     ) -> Option<T> {
-        for krate in def_crates(db, &self.ty, krate.id)? {
+        for krate in method_resolution::def_crates(db, &self.ty, krate.id)? {
             let impls = db.inherent_impls_in_crate(krate);
 
             for impl_def in impls.for_self_ty(&self.ty) {
@@ -2345,13 +2511,13 @@ impl Type {
             match ty.kind(&Interner) {
                 TyKind::Adt(_, substs) => {
                     cb(type_.derived(ty.clone()));
-                    walk_substs(db, type_, &substs, cb);
+                    walk_substs(db, type_, substs, cb);
                 }
                 TyKind::AssociatedType(_, substs) => {
                     if let Some(_) = ty.associated_type_parent_trait(db) {
                         cb(type_.derived(ty.clone()));
                     }
-                    walk_substs(db, type_, &substs, cb);
+                    walk_substs(db, type_, substs, cb);
                 }
                 TyKind::OpaqueType(_, subst) => {
                     if let Some(bounds) = ty.impl_trait_bounds(db) {
@@ -2391,7 +2557,7 @@ impl Type {
                 TyKind::FnDef(_, substs)
                 | TyKind::Tuple(_, substs)
                 | TyKind::Closure(.., substs) => {
-                    walk_substs(db, type_, &substs, cb);
+                    walk_substs(db, type_, substs, cb);
                 }
                 TyKind::Function(hir_ty::FnPointer { substitution, .. }) => {
                     walk_substs(db, type_, &substitution.0, cb);
@@ -2522,18 +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 d522d5245..613266e07 100644
--- a/crates/hir/src/semantics.rs
+++ b/crates/hir/src/semantics.rs
@@ -192,7 +192,7 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         node: &SyntaxNode,
         offset: TextSize,
     ) -> Option<N> {
-        if let Some(it) = find_node_at_offset(&node, offset) {
+        if let Some(it) = find_node_at_offset(node, offset) {
             return Some(it);
         }
 
@@ -744,7 +744,7 @@ impl<'db> SemanticsImpl<'db> {
                     return None;
                 }
 
-                let func = self.resolve_method_call(&method_call_expr).map(Function::from)?;
+                let func = self.resolve_method_call(method_call_expr).map(Function::from)?;
                 let res = match func.self_param(self.db)?.access(self.db) {
                     Access::Shared | Access::Exclusive => true,
                     Access::Owned => false,
diff --git a/crates/hir/src/source_analyzer.rs b/crates/hir/src/source_analyzer.rs
index 37a050415..c9744d81d 100644
--- a/crates/hir/src/source_analyzer.rs
+++ b/crates/hir/src/source_analyzer.rs
@@ -222,7 +222,7 @@ impl SourceAnalyzer {
             Pat::Path(path) => path,
             _ => return None,
         };
-        let res = resolve_hir_path(db, &self.resolver, &path)?;
+        let res = resolve_hir_path(db, &self.resolver, path)?;
         match res {
             PathResolution::Def(def) => Some(def),
             _ => None,
@@ -329,7 +329,7 @@ impl SourceAnalyzer {
 
         let (variant, missing_fields, _exhaustive) =
             record_literal_missing_fields(db, infer, expr_id, &body[expr_id])?;
-        let res = self.missing_fields(db, krate, &substs, variant, missing_fields);
+        let res = self.missing_fields(db, krate, substs, variant, missing_fields);
         Some(res)
     }
 
@@ -347,7 +347,7 @@ impl SourceAnalyzer {
 
         let (variant, missing_fields, _exhaustive) =
             record_pattern_missing_fields(db, infer, pat_id, &body[pat_id])?;
-        let res = self.missing_fields(db, krate, &substs, variant, missing_fields);
+        let res = self.missing_fields(db, krate, substs, variant, missing_fields);
         Some(res)
     }
 
diff --git a/crates/hir_def/Cargo.toml b/crates/hir_def/Cargo.toml
index 43324d8d9..bb86f6a73 100644
--- a/crates/hir_def/Cargo.toml
+++ b/crates/hir_def/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = { version = "1.1", features = ["thread-local"] }
+cov-mark = "2.0.0-pre.1"
 dashmap = { version = "4.0.2", features = ["raw-api"] }
 log = "0.4.8"
 once_cell = "1.3.1"
diff --git a/crates/hir_def/src/attr.rs b/crates/hir_def/src/attr.rs
index d9f9fadc1..d07adb084 100644
--- a/crates/hir_def/src/attr.rs
+++ b/crates/hir_def/src/attr.rs
@@ -583,13 +583,13 @@ impl AttrSourceMap {
                 .get(id.ast_index as usize)
                 .unwrap_or_else(|| panic!("cannot find doc comment at index {:?}", id))
                 .clone()
-                .map(|attr| Either::Right(attr))
+                .map(Either::Right)
         } else {
             self.attrs
                 .get(id.ast_index as usize)
                 .unwrap_or_else(|| panic!("cannot find `Attr` at index {:?}", id))
                 .clone()
-                .map(|attr| Either::Left(attr))
+                .map(Either::Left)
         }
     }
 }
@@ -606,7 +606,7 @@ pub struct DocsRangeMap {
 impl DocsRangeMap {
     pub fn map(&self, range: TextRange) -> Option<InFile<TextRange>> {
         let found = self.mapping.binary_search_by(|(probe, ..)| probe.ordering(range)).ok()?;
-        let (line_docs_range, idx, original_line_src_range) = self.mapping[found].clone();
+        let (line_docs_range, idx, original_line_src_range) = self.mapping[found];
         if !line_docs_range.contains_range(range) {
             return None;
         }
diff --git a/crates/hir_def/src/body/lower.rs b/crates/hir_def/src/body/lower.rs
index da1fdac33..bed4c4994 100644
--- a/crates/hir_def/src/body/lower.rs
+++ b/crates/hir_def/src/body/lower.rs
@@ -1000,18 +1000,18 @@ impl From<ast::LiteralKind> for Literal {
             // FIXME: these should have actual values filled in, but unsure on perf impact
             LiteralKind::IntNumber(lit) => {
                 if let builtin @ Some(_) = lit.suffix().and_then(BuiltinFloat::from_suffix) {
-                    return Literal::Float(Default::default(), builtin);
+                    Literal::Float(Default::default(), builtin)
                 } else if let builtin @ Some(_) =
-                    lit.suffix().and_then(|it| BuiltinInt::from_suffix(&it))
+                    lit.suffix().and_then(|it| BuiltinInt::from_suffix(it))
                 {
                     Literal::Int(lit.value().unwrap_or(0) as i128, builtin)
                 } else {
-                    let builtin = lit.suffix().and_then(|it| BuiltinUint::from_suffix(&it));
+                    let builtin = lit.suffix().and_then(|it| BuiltinUint::from_suffix(it));
                     Literal::Uint(lit.value().unwrap_or(0), builtin)
                 }
             }
             LiteralKind::FloatNumber(lit) => {
-                let ty = lit.suffix().and_then(|it| BuiltinFloat::from_suffix(&it));
+                let ty = lit.suffix().and_then(|it| BuiltinFloat::from_suffix(it));
                 Literal::Float(Default::default(), ty)
             }
             LiteralKind::ByteString(bs) => {
diff --git a/crates/hir_def/src/body/scope.rs b/crates/hir_def/src/body/scope.rs
index 6764de3a7..58a1fc81c 100644
--- a/crates/hir_def/src/body/scope.rs
+++ b/crates/hir_def/src/body/scope.rs
@@ -198,7 +198,7 @@ fn compute_expr_scopes(expr: ExprId, body: &Body, scopes: &mut ExprScopes, scope
         }
         Expr::Lambda { args, body: body_expr, .. } => {
             let scope = scopes.new_scope(scope);
-            scopes.add_params_bindings(body, scope, &args);
+            scopes.add_params_bindings(body, scope, args);
             compute_expr_scopes(*body_expr, body, scopes, scope);
         }
         Expr::Match { expr, arms } => {
diff --git a/crates/hir_def/src/body/tests.rs b/crates/hir_def/src/body/tests.rs
index d4fae05a6..27d837d47 100644
--- a/crates/hir_def/src/body/tests.rs
+++ b/crates/hir_def/src/body/tests.rs
@@ -3,7 +3,7 @@ mod block;
 use base_db::{fixture::WithFixture, SourceDatabase};
 use expect_test::Expect;
 
-use crate::{test_db::TestDB, ModuleDefId};
+use crate::ModuleDefId;
 
 use super::*;
 
@@ -28,11 +28,6 @@ fn lower(ra_fixture: &str) -> Arc<Body> {
     db.body(fn_def.unwrap().into())
 }
 
-fn check_diagnostics(ra_fixture: &str) {
-    let db: TestDB = TestDB::with_files(ra_fixture);
-    db.check_diagnostics();
-}
-
 fn block_def_map_at(ra_fixture: &str) -> String {
     let (db, position) = crate::test_db::TestDB::with_position(ra_fixture);
 
@@ -57,7 +52,7 @@ fn check_at(ra_fixture: &str, expect: Expect) {
 fn your_stack_belongs_to_me() {
     cov_mark::check!(your_stack_belongs_to_me);
     lower(
-        "
+        r#"
 macro_rules! n_nuple {
     ($e:tt) => ();
     ($($rest:tt)*) => {{
@@ -65,7 +60,7 @@ macro_rules! n_nuple {
     }};
 }
 fn main() { n_nuple!(1,2,3); }
-",
+"#,
     );
 }
 
@@ -73,7 +68,7 @@ fn main() { n_nuple!(1,2,3); }
 fn macro_resolve() {
     // Regression test for a path resolution bug introduced with inner item handling.
     lower(
-        r"
+        r#"
 macro_rules! vec {
     () => { () };
     ($elem:expr; $n:expr) => { () };
@@ -84,140 +79,6 @@ mod m {
         let _ = vec![FileSet::default(); self.len()];
     }
 }
-      ",
-    );
-}
-
-#[test]
-fn cfg_diagnostics() {
-    check_diagnostics(
-        r"
-fn f() {
-    // The three g̶e̶n̶d̶e̶r̶s̶ statements:
-
-    #[cfg(a)] fn f() {}  // Item statement
-  //^^^^^^^^^^^^^^^^^^^ InactiveCode
-    #[cfg(a)] {}         // Expression statement
-  //^^^^^^^^^^^^ InactiveCode
-    #[cfg(a)] let x = 0; // let statement
-  //^^^^^^^^^^^^^^^^^^^^ InactiveCode
-
-    abc(#[cfg(a)] 0);
-      //^^^^^^^^^^^ InactiveCode
-    let x = Struct {
-        #[cfg(a)] f: 0,
-      //^^^^^^^^^^^^^^ InactiveCode
-    };
-    match () {
-        () => (),
-        #[cfg(a)] () => (),
-      //^^^^^^^^^^^^^^^^^^ InactiveCode
-    }
-
-    #[cfg(a)] 0          // Trailing expression of block
-  //^^^^^^^^^^^ InactiveCode
-}
-    ",
-    );
-}
-
-#[test]
-fn macro_diag_builtin() {
-    check_diagnostics(
-        r#"
-#[rustc_builtin_macro]
-macro_rules! env {}
-
-#[rustc_builtin_macro]
-macro_rules! include {}
-
-#[rustc_builtin_macro]
-macro_rules! compile_error {}
-
-#[rustc_builtin_macro]
-macro_rules! format_args {
-    () => {}
-}
-
-fn f() {
-    // Test a handful of built-in (eager) macros:
-
-    include!(invalid);
-  //^^^^^^^^^^^^^^^^^ could not convert tokens
-    include!("does not exist");
-  //^^^^^^^^^^^^^^^^^^^^^^^^^^ failed to load file `does not exist`
-
-    env!(invalid);
-  //^^^^^^^^^^^^^ could not convert tokens
-
-    env!("OUT_DIR");
-  //^^^^^^^^^^^^^^^ `OUT_DIR` not set, enable "run build scripts" to fix
-
-    compile_error!("compile_error works");
-  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ compile_error works
-
-    // Lazy:
-
-    format_args!();
-  //^^^^^^^^^^^^^^ no rule matches input tokens
-}
-        "#,
-    );
-}
-
-#[test]
-fn macro_rules_diag() {
-    check_diagnostics(
-        r#"
-macro_rules! m {
-    () => {};
-}
-fn f() {
-    m!();
-
-    m!(hi);
-  //^^^^^^ leftover tokens
-}
-      "#,
+"#,
     );
 }
-
-#[test]
-fn unresolved_macro_diag() {
-    check_diagnostics(
-        r#"
-fn f() {
-    m!();
-  //^^^^ UnresolvedMacroCall
-}
-      "#,
-    );
-}
-
-#[test]
-fn dollar_crate_in_builtin_macro() {
-    check_diagnostics(
-        r#"
-#[macro_export]
-#[rustc_builtin_macro]
-macro_rules! format_args {}
-
-#[macro_export]
-macro_rules! arg {
-    () => {}
-}
-
-#[macro_export]
-macro_rules! outer {
-    () => {
-        $crate::format_args!( "", $crate::arg!(1) )
-    };
-}
-
-fn f() {
-    outer!();
-  //^^^^^^^^ leftover tokens
-}
-        "#,
-    )
-}
diff --git a/crates/hir_def/src/body/tests/block.rs b/crates/hir_def/src/body/tests/block.rs
index bc3d0f138..15c10d053 100644
--- a/crates/hir_def/src/body/tests/block.rs
+++ b/crates/hir_def/src/body/tests/block.rs
@@ -163,14 +163,14 @@ fn legacy_macro_items() {
     // correctly.
     check_at(
         r#"
-macro_rules! hit {
+macro_rules! mark {
     () => {
         struct Hit {}
     }
 }
 
 fn f() {
-    hit!();
+    mark!();
     $0
 }
 "#,
@@ -193,20 +193,20 @@ use core::cov_mark;
 
 fn f() {
     fn nested() {
-        cov_mark::hit!(Hit);
+        cov_mark::mark!(Hit);
         $0
     }
 }
 //- /core.rs crate:core
 pub mod cov_mark {
     #[macro_export]
-    macro_rules! _hit {
+    macro_rules! _mark {
         ($name:ident) => {
             struct $name {}
         }
     }
 
-    pub use crate::_hit as hit;
+    pub use crate::_mark as mark;
 }
 "#,
         expect![[r#"
diff --git a/crates/hir_def/src/generics.rs b/crates/hir_def/src/generics.rs
index 44d22b918..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());
@@ -277,10 +277,10 @@ 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));
+            self.fill_bounds(lower_ctx, &type_param, Either::Left(type_ref));
         }
         for lifetime_param in params.lifetime_params() {
             let name =
@@ -289,7 +289,7 @@ impl GenericParams {
             let param_id = self.lifetimes.alloc(param);
             sm.lifetime_params.insert(param_id, lifetime_param.clone());
             let lifetime_ref = LifetimeRef::new_name(name);
-            self.fill_bounds(&lower_ctx, &lifetime_param, Either::Right(lifetime_ref));
+            self.fill_bounds(lower_ctx, &lifetime_param, Either::Right(lifetime_ref));
         }
         for const_param in params.const_params() {
             let name = const_param.name().map_or_else(Name::missing, |it| it.as_name());
@@ -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_scope.rs b/crates/hir_def/src/item_scope.rs
index 0f74f050d..08407ebfa 100644
--- a/crates/hir_def/src/item_scope.rs
+++ b/crates/hir_def/src/item_scope.rs
@@ -59,7 +59,7 @@ pub struct ItemScope {
 pub(crate) static BUILTIN_SCOPE: Lazy<FxHashMap<Name, PerNs>> = Lazy::new(|| {
     BuiltinType::ALL
         .iter()
-        .map(|(name, ty)| (name.clone(), PerNs::types(ty.clone().into(), Visibility::Public)))
+        .map(|(name, ty)| (name.clone(), PerNs::types((*ty).into(), Visibility::Public)))
         .collect()
 });
 
diff --git a/crates/hir_def/src/item_tree/lower.rs b/crates/hir_def/src/item_tree/lower.rs
index cfda7cb32..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());
@@ -823,7 +823,7 @@ fn is_intrinsic_fn_unsafe(name: &Name) -> bool {
         known::type_name,
         known::variant_count,
     ]
-    .contains(&name)
+    .contains(name)
 }
 
 fn lower_abi(abi: ast::Abi) -> Interned<str> {
@@ -855,7 +855,7 @@ impl UseTreeLowering<'_> {
                 // E.g. `use something::{inner}` (prefix is `None`, path is `something`)
                 // or `use something::{path::{inner::{innerer}}}` (prefix is `something::path`, path is `inner`)
                 Some(path) => {
-                    match ModPath::from_src(self.db, path, &self.hygiene) {
+                    match ModPath::from_src(self.db, path, self.hygiene) {
                         Some(it) => Some(it),
                         None => return None, // FIXME: report errors somewhere
                     }
@@ -874,7 +874,7 @@ impl UseTreeLowering<'_> {
         } else {
             let is_glob = tree.star_token().is_some();
             let path = match tree.path() {
-                Some(path) => Some(ModPath::from_src(self.db, path, &self.hygiene)?),
+                Some(path) => Some(ModPath::from_src(self.db, path, self.hygiene)?),
                 None => None,
             };
             let alias = tree.rename().map(|a| {
diff --git a/crates/hir_def/src/item_tree/pretty.rs b/crates/hir_def/src/item_tree/pretty.rs
index cc9944a22..b1e1b70d0 100644
--- a/crates/hir_def/src/item_tree/pretty.rs
+++ b/crates/hir_def/src/item_tree/pretty.rs
@@ -426,7 +426,7 @@ impl<'a> Printer<'a> {
                         w!(self, " {{");
                         self.indented(|this| {
                             for item in &**items {
-                                this.print_mod_item((*item).into());
+                                this.print_mod_item(*item);
                             }
                         });
                         wln!(self, "}}");
diff --git a/crates/hir_def/src/lib.rs b/crates/hir_def/src/lib.rs
index 987485acc..bb174aec8 100644
--- a/crates/hir_def/src/lib.rs
+++ b/crates/hir_def/src/lib.rs
@@ -112,6 +112,10 @@ impl ModuleId {
         self.def_map(db).containing_module(self.local_id)
     }
 
+    pub fn containing_block(&self) -> Option<BlockId> {
+        self.block
+    }
+
     /// Returns `true` if this module represents a block expression.
     ///
     /// Returns `false` if this module is a submodule *inside* a block expression
@@ -581,6 +585,18 @@ impl HasModule for GenericDefId {
     }
 }
 
+impl HasModule for TypeAliasId {
+    fn module(&self, db: &dyn db::DefDatabase) -> ModuleId {
+        self.lookup(db).module(db)
+    }
+}
+
+impl HasModule for TraitId {
+    fn module(&self, db: &dyn db::DefDatabase) -> ModuleId {
+        self.lookup(db).container
+    }
+}
+
 impl HasModule for StaticLoc {
     fn module(&self, _db: &dyn db::DefDatabase) -> ModuleId {
         self.container
@@ -731,13 +747,11 @@ fn macro_call_as_call_id(
         )
         .map(MacroCallId::from)
     } else {
-        Ok(def
-            .as_lazy_macro(
-                db.upcast(),
-                krate,
-                MacroCallKind::FnLike { ast_id: call.ast_id, fragment },
-            )
-            .into())
+        Ok(def.as_lazy_macro(
+            db.upcast(),
+            krate,
+            MacroCallKind::FnLike { ast_id: call.ast_id, fragment },
+        ))
     };
     Ok(res)
 }
@@ -756,17 +770,15 @@ fn derive_macro_as_call_id(
         .segments()
         .last()
         .ok_or_else(|| UnresolvedMacro { path: item_attr.path.clone() })?;
-    let res = def
-        .as_lazy_macro(
-            db.upcast(),
-            krate,
-            MacroCallKind::Derive {
-                ast_id: item_attr.ast_id,
-                derive_name: last_segment.to_string(),
-                derive_attr_index: derive_attr.ast_index,
-            },
-        )
-        .into();
+    let res = def.as_lazy_macro(
+        db.upcast(),
+        krate,
+        MacroCallKind::Derive {
+            ast_id: item_attr.ast_id,
+            derive_name: last_segment.to_string(),
+            derive_attr_index: derive_attr.ast_index,
+        },
+    );
     Ok(res)
 }
 
@@ -794,17 +806,15 @@ fn attr_macro_as_call_id(
     // The parentheses are always disposed here.
     arg.delimiter = None;
 
-    let res = def
-        .as_lazy_macro(
-            db.upcast(),
-            krate,
-            MacroCallKind::Attr {
-                ast_id: item_attr.ast_id,
-                attr_name: last_segment.to_string(),
-                attr_args: arg,
-                invoc_attr_index: macro_attr.id.ast_index,
-            },
-        )
-        .into();
+    let res = def.as_lazy_macro(
+        db.upcast(),
+        krate,
+        MacroCallKind::Attr {
+            ast_id: item_attr.ast_id,
+            attr_name: last_segment.to_string(),
+            attr_args: arg,
+            invoc_attr_index: macro_attr.id.ast_index,
+        },
+    );
     Ok(res)
 }
diff --git a/crates/hir_def/src/nameres/collector.rs b/crates/hir_def/src/nameres/collector.rs
index 93f30f23d..fc2c50fb8 100644
--- a/crates/hir_def/src/nameres/collector.rs
+++ b/crates/hir_def/src/nameres/collector.rs
@@ -500,7 +500,7 @@ impl DefCollector<'_> {
             let (per_ns, _) = self.def_map.resolve_path(
                 self.db,
                 self.def_map.root,
-                &path,
+                path,
                 BuiltinShadowMode::Other,
             );
 
@@ -722,7 +722,7 @@ impl DefCollector<'_> {
         if import.is_extern_crate {
             let res = self.def_map.resolve_name_in_extern_prelude(
                 self.db,
-                &import
+                import
                     .path
                     .as_ident()
                     .expect("extern crate should have been desugared to one-element path"),
@@ -1351,7 +1351,7 @@ impl ModCollector<'_, '_> {
                     let imports = Import::from_use(
                         self.def_collector.db,
                         krate,
-                        &self.item_tree,
+                        self.item_tree,
                         ItemTreeId::new(self.file_id, import_id),
                     );
                     self.def_collector.unresolved_imports.extend(imports.into_iter().map(
@@ -1368,7 +1368,7 @@ impl ModCollector<'_, '_> {
                         import: Import::from_extern_crate(
                             self.def_collector.db,
                             krate,
-                            &self.item_tree,
+                            self.item_tree,
                             ItemTreeId::new(self.file_id, import_id),
                         ),
                         status: PartialResolvedImport::Unresolved,
@@ -1889,7 +1889,7 @@ impl ModCollector<'_, '_> {
                     self.def_collector.def_map.with_ancestor_maps(
                         self.def_collector.db,
                         self.module_id,
-                        &mut |map, module| map[module].scope.get_legacy_macro(&name),
+                        &mut |map, module| map[module].scope.get_legacy_macro(name),
                     )
                 })
             },
@@ -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/nameres/path_resolution.rs b/crates/hir_def/src/nameres/path_resolution.rs
index c984148c3..629bc7952 100644
--- a/crates/hir_def/src/nameres/path_resolution.rs
+++ b/crates/hir_def/src/nameres/path_resolution.rs
@@ -93,7 +93,7 @@ impl DefMap {
         let mut vis = match visibility {
             RawVisibility::Module(path) => {
                 let (result, remaining) =
-                    self.resolve_path(db, original_module, &path, BuiltinShadowMode::Module);
+                    self.resolve_path(db, original_module, path, BuiltinShadowMode::Module);
                 if remaining.is_some() {
                     return None;
                 }
@@ -205,7 +205,7 @@ impl DefMap {
                     None => return ResolvePathResult::empty(ReachedFixedPoint::Yes),
                 };
                 log::debug!("resolving {:?} in crate root (+ extern prelude)", segment);
-                self.resolve_name_in_crate_root_or_extern_prelude(db, &segment)
+                self.resolve_name_in_crate_root_or_extern_prelude(db, segment)
             }
             PathKind::Plain => {
                 let (_, segment) = match segments.next() {
@@ -222,7 +222,7 @@ impl DefMap {
                     if path.segments().len() == 1 { shadow } else { BuiltinShadowMode::Module };
 
                 log::debug!("resolving {:?} in module", segment);
-                self.resolve_name_in_module(db, original_module, &segment, prefer_module)
+                self.resolve_name_in_module(db, original_module, segment, prefer_module)
             }
             PathKind::Super(lvl) => {
                 let mut module = original_module;
@@ -269,7 +269,7 @@ impl DefMap {
                     Some((_, segment)) => segment,
                     None => return ResolvePathResult::empty(ReachedFixedPoint::Yes),
                 };
-                if let Some(def) = self.extern_prelude.get(&segment) {
+                if let Some(def) = self.extern_prelude.get(segment) {
                     log::debug!("absolute path {:?} resolved to crate {:?}", path, def);
                     PerNs::types(*def, Visibility::Public)
                 } else {
@@ -319,13 +319,13 @@ impl DefMap {
                     };
 
                     // Since it is a qualified path here, it should not contains legacy macros
-                    module_data.scope.get(&segment)
+                    module_data.scope.get(segment)
                 }
                 ModuleDefId::AdtId(AdtId::EnumId(e)) => {
                     // enum variant
                     cov_mark::hit!(can_import_enum_variant);
                     let enum_data = db.enum_data(e);
-                    match enum_data.variant(&segment) {
+                    match enum_data.variant(segment) {
                         Some(local_id) => {
                             let variant = EnumVariantId { parent: e, local_id };
                             match &*enum_data.variants[local_id].variant_data {
diff --git a/crates/hir_def/src/nameres/tests.rs b/crates/hir_def/src/nameres/tests.rs
index 58c01354a..cf43f2a96 100644
--- a/crates/hir_def/src/nameres/tests.rs
+++ b/crates/hir_def/src/nameres/tests.rs
@@ -2,7 +2,6 @@ mod globs;
 mod incremental;
 mod macros;
 mod mod_resolution;
-mod diagnostics;
 mod primitives;
 
 use std::sync::Arc;
diff --git a/crates/hir_def/src/nameres/tests/diagnostics.rs b/crates/hir_def/src/nameres/tests/diagnostics.rs
deleted file mode 100644
index ec6670952..000000000
--- a/crates/hir_def/src/nameres/tests/diagnostics.rs
+++ /dev/null
@@ -1,229 +0,0 @@
-use base_db::fixture::WithFixture;
-
-use crate::test_db::TestDB;
-
-fn check_diagnostics(ra_fixture: &str) {
-    let db: TestDB = TestDB::with_files(ra_fixture);
-    db.check_diagnostics();
-}
-
-fn check_no_diagnostics(ra_fixture: &str) {
-    let db: TestDB = TestDB::with_files(ra_fixture);
-    db.check_no_diagnostics();
-}
-
-#[test]
-fn unresolved_import() {
-    check_diagnostics(
-        r"
-        use does_exist;
-        use does_not_exist;
-      //^^^^^^^^^^^^^^^^^^^ UnresolvedImport
-
-        mod does_exist {}
-        ",
-    );
-}
-
-#[test]
-fn unresolved_extern_crate() {
-    check_diagnostics(
-        r"
-        //- /main.rs crate:main deps:core
-        extern crate core;
-          extern crate doesnotexist;
-        //^^^^^^^^^^^^^^^^^^^^^^^^^^ UnresolvedExternCrate
-        //- /lib.rs crate:core
-        ",
-    );
-}
-
-#[test]
-fn extern_crate_self_as() {
-    cov_mark::check!(extern_crate_self_as);
-    check_diagnostics(
-        r"
-        //- /lib.rs
-          extern crate doesnotexist;
-        //^^^^^^^^^^^^^^^^^^^^^^^^^^ UnresolvedExternCrate
-        // Should not error.
-        extern crate self as foo;
-        struct Foo;
-        use foo::Foo as Bar;
-        ",
-    );
-}
-
-#[test]
-fn dedup_unresolved_import_from_unresolved_crate() {
-    check_diagnostics(
-        r"
-        //- /main.rs crate:main
-        mod a {
-            extern crate doesnotexist;
-          //^^^^^^^^^^^^^^^^^^^^^^^^^^ UnresolvedExternCrate
-
-            // Should not error, since we already errored for the missing crate.
-            use doesnotexist::{self, bla, *};
-
-            use crate::doesnotexist;
-          //^^^^^^^^^^^^^^^^^^^^^^^^ UnresolvedImport
-        }
-
-        mod m {
-            use super::doesnotexist;
-          //^^^^^^^^^^^^^^^^^^^^^^^^ UnresolvedImport
-        }
-        ",
-    );
-}
-
-#[test]
-fn unresolved_module() {
-    check_diagnostics(
-        r"
-        //- /lib.rs
-        mod foo;
-          mod bar;
-        //^^^^^^^^ UnresolvedModule
-        mod baz {}
-        //- /foo.rs
-        ",
-    );
-}
-
-#[test]
-fn inactive_item() {
-    // Additional tests in `cfg` crate. This only tests disabled cfgs.
-
-    check_diagnostics(
-        r#"
-        //- /lib.rs
-          #[cfg(no)] pub fn f() {}
-        //^^^^^^^^^^^^^^^^^^^^^^^^ UnconfiguredCode
-
-          #[cfg(no)] #[cfg(no2)] mod m;
-        //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ UnconfiguredCode
-
-          #[cfg(all(not(a), b))] enum E {}
-        //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ UnconfiguredCode
-
-          #[cfg(feature = "std")] use std;
-        //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ UnconfiguredCode
-        "#,
-    );
-}
-
-/// Tests that `cfg` attributes behind `cfg_attr` is handled properly.
-#[test]
-fn inactive_via_cfg_attr() {
-    cov_mark::check!(cfg_attr_active);
-    check_diagnostics(
-        r#"
-        //- /lib.rs
-          #[cfg_attr(not(never), cfg(no))] fn f() {}
-        //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ UnconfiguredCode
-
-          #[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() {}
-        //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ UnconfiguredCode
-        "#,
-    );
-}
-
-#[test]
-fn unresolved_legacy_scope_macro() {
-    check_diagnostics(
-        r#"
-        //- /lib.rs
-          macro_rules! m { () => {} }
-
-          m!();
-          m2!();
-        //^^^^^^ UnresolvedMacroCall
-        "#,
-    );
-}
-
-#[test]
-fn unresolved_module_scope_macro() {
-    check_diagnostics(
-        r#"
-        //- /lib.rs
-          mod mac {
-            #[macro_export]
-            macro_rules! m { () => {} }
-          }
-
-          self::m!();
-          self::m2!();
-        //^^^^^^^^^^^^ UnresolvedMacroCall
-        "#,
-    );
-}
-
-#[test]
-fn builtin_macro_fails_expansion() {
-    check_diagnostics(
-        r#"
-        //- /lib.rs
-          #[rustc_builtin_macro]
-          macro_rules! include { () => {} }
-
-          include!("doesntexist");
-        //^^^^^^^^^^^^^^^^^^^^^^^^ failed to load file `doesntexist`
-        "#,
-    );
-}
-
-#[test]
-fn include_macro_should_allow_empty_content() {
-    check_no_diagnostics(
-        r#"
-        //- /lib.rs
-          #[rustc_builtin_macro]
-          macro_rules! include { () => {} }
-
-          include!("bar.rs");
-        //- /bar.rs
-          // empty
-        "#,
-    );
-}
-
-#[test]
-fn good_out_dir_diagnostic() {
-    check_diagnostics(
-        r#"
-        #[rustc_builtin_macro]
-        macro_rules! include { () => {} }
-        #[rustc_builtin_macro]
-        macro_rules! env { () => {} }
-        #[rustc_builtin_macro]
-        macro_rules! concat { () => {} }
-
-        include!(concat!(env!("OUT_DIR"), "/out.rs"));
-      //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `OUT_DIR` not set, enable "run build scripts" to fix
-        "#,
-    );
-}
-
-#[test]
-fn register_attr_and_tool() {
-    cov_mark::check!(register_attr);
-    cov_mark::check!(register_tool);
-    check_no_diagnostics(
-        r#"
-#![register_tool(tool)]
-#![register_attr(attr)]
-
-#[tool::path]
-#[attr]
-struct S;
-        "#,
-    );
-    // NB: we don't currently emit diagnostics here
-}
diff --git a/crates/hir_def/src/path/lower.rs b/crates/hir_def/src/path/lower.rs
index f6220aa92..27345d07c 100644
--- a/crates/hir_def/src/path/lower.rs
+++ b/crates/hir_def/src/path/lower.rs
@@ -208,13 +208,13 @@ fn lower_generic_args_from_fn_path(
     let params = params?;
     let mut param_types = Vec::new();
     for param in params.params() {
-        let type_ref = TypeRef::from_ast_opt(&ctx, param.ty());
+        let type_ref = TypeRef::from_ast_opt(ctx, param.ty());
         param_types.push(type_ref);
     }
     let arg = GenericArg::Type(TypeRef::Tuple(param_types));
     args.push(arg);
     if let Some(ret_type) = ret_type {
-        let type_ref = TypeRef::from_ast_opt(&ctx, ret_type.ty());
+        let type_ref = TypeRef::from_ast_opt(ctx, ret_type.ty());
         bindings.push(AssociatedTypeBinding {
             name: name![Output],
             type_ref: Some(type_ref),
diff --git a/crates/hir_def/src/resolver.rs b/crates/hir_def/src/resolver.rs
index fb8a6f260..d4681fa3e 100644
--- a/crates/hir_def/src/resolver.rs
+++ b/crates/hir_def/src/resolver.rs
@@ -133,7 +133,7 @@ impl Resolver {
             Some(it) => it,
             None => return PerNs::none(),
         };
-        let (module_res, segment_index) = item_map.resolve_path(db, module, &path, shadow);
+        let (module_res, segment_index) = item_map.resolve_path(db, module, path, shadow);
         if segment_index.is_some() {
             return PerNs::none();
         }
@@ -150,7 +150,7 @@ impl Resolver {
         path: &ModPath,
     ) -> Option<TraitId> {
         let (item_map, module) = self.module_scope()?;
-        let (module_res, ..) = item_map.resolve_path(db, module, &path, BuiltinShadowMode::Module);
+        let (module_res, ..) = item_map.resolve_path(db, module, path, BuiltinShadowMode::Module);
         match module_res.take_types()? {
             ModuleDefId::TraitId(it) => Some(it),
             _ => None,
@@ -325,7 +325,7 @@ impl Resolver {
         path: &ModPath,
     ) -> Option<MacroDefId> {
         let (item_map, module) = self.module_scope()?;
-        item_map.resolve_path(db, module, &path, BuiltinShadowMode::Other).0.take_macros()
+        item_map.resolve_path(db, module, path, BuiltinShadowMode::Other).0.take_macros()
     }
 
     pub fn process_all_names(&self, db: &dyn DefDatabase, f: &mut dyn FnMut(Name, ScopeDef)) {
@@ -561,7 +561,7 @@ impl ModuleItemMap {
         path: &ModPath,
     ) -> Option<ResolveValueResult> {
         let (module_def, idx) =
-            self.def_map.resolve_path_locally(db, self.module_id, &path, BuiltinShadowMode::Other);
+            self.def_map.resolve_path_locally(db, self.module_id, path, BuiltinShadowMode::Other);
         match idx {
             None => {
                 let value = to_value_ns(module_def)?;
@@ -591,7 +591,7 @@ impl ModuleItemMap {
         path: &ModPath,
     ) -> Option<(TypeNs, Option<usize>)> {
         let (module_def, idx) =
-            self.def_map.resolve_path_locally(db, self.module_id, &path, BuiltinShadowMode::Other);
+            self.def_map.resolve_path_locally(db, self.module_id, path, BuiltinShadowMode::Other);
         let res = to_type_ns(module_def)?;
         Some((res, idx))
     }
diff --git a/crates/hir_def/src/test_db.rs b/crates/hir_def/src/test_db.rs
index b20b066e2..2635b556e 100644
--- a/crates/hir_def/src/test_db.rs
+++ b/crates/hir_def/src/test_db.rs
@@ -6,19 +6,16 @@ use std::{
 };
 
 use base_db::{
-    salsa, CrateId, FileId, FileLoader, FileLoaderDelegate, FilePosition, FileRange, Upcast,
+    salsa, AnchoredPath, CrateId, FileId, FileLoader, FileLoaderDelegate, FilePosition,
+    SourceDatabase, Upcast,
 };
-use base_db::{AnchoredPath, SourceDatabase};
 use hir_expand::{db::AstDatabase, InFile};
-use rustc_hash::FxHashMap;
 use rustc_hash::FxHashSet;
-use syntax::{algo, ast, AstNode, SyntaxNode, SyntaxNodePtr, TextRange, TextSize};
-use test_utils::extract_annotations;
+use syntax::{algo, ast, AstNode};
 
 use crate::{
-    body::BodyDiagnostic,
     db::DefDatabase,
-    nameres::{diagnostics::DefDiagnosticKind, DefMap, ModuleSource},
+    nameres::{DefMap, ModuleSource},
     src::HasSource,
     LocalModuleId, Lookup, ModuleDefId, ModuleId,
 };
@@ -245,145 +242,4 @@ impl TestDB {
             })
             .collect()
     }
-
-    pub(crate) fn extract_annotations(&self) -> FxHashMap<FileId, Vec<(TextRange, String)>> {
-        let mut files = Vec::new();
-        let crate_graph = self.crate_graph();
-        for krate in crate_graph.iter() {
-            let crate_def_map = self.crate_def_map(krate);
-            for (module_id, _) in crate_def_map.modules() {
-                let file_id = crate_def_map[module_id].origin.file_id();
-                files.extend(file_id)
-            }
-        }
-        assert!(!files.is_empty());
-        files
-            .into_iter()
-            .filter_map(|file_id| {
-                let text = self.file_text(file_id);
-                let annotations = extract_annotations(&text);
-                if annotations.is_empty() {
-                    return None;
-                }
-                Some((file_id, annotations))
-            })
-            .collect()
-    }
-
-    pub(crate) fn diagnostics(&self, cb: &mut dyn FnMut(FileRange, String)) {
-        let crate_graph = self.crate_graph();
-        for krate in crate_graph.iter() {
-            let crate_def_map = self.crate_def_map(krate);
-
-            for diag in crate_def_map.diagnostics() {
-                let (node, message): (InFile<SyntaxNode>, &str) = match &diag.kind {
-                    DefDiagnosticKind::UnresolvedModule { ast, .. } => {
-                        let node = ast.to_node(self.upcast());
-                        (InFile::new(ast.file_id, node.syntax().clone()), "UnresolvedModule")
-                    }
-                    DefDiagnosticKind::UnresolvedExternCrate { ast, .. } => {
-                        let node = ast.to_node(self.upcast());
-                        (InFile::new(ast.file_id, node.syntax().clone()), "UnresolvedExternCrate")
-                    }
-                    DefDiagnosticKind::UnresolvedImport { id, .. } => {
-                        let item_tree = id.item_tree(self.upcast());
-                        let import = &item_tree[id.value];
-                        let node = InFile::new(id.file_id(), import.ast_id).to_node(self.upcast());
-                        (InFile::new(id.file_id(), node.syntax().clone()), "UnresolvedImport")
-                    }
-                    DefDiagnosticKind::UnconfiguredCode { ast, .. } => {
-                        let node = ast.to_node(self.upcast());
-                        (InFile::new(ast.file_id, node.syntax().clone()), "UnconfiguredCode")
-                    }
-                    DefDiagnosticKind::UnresolvedProcMacro { ast, .. } => {
-                        (ast.to_node(self.upcast()), "UnresolvedProcMacro")
-                    }
-                    DefDiagnosticKind::UnresolvedMacroCall { ast, .. } => {
-                        let node = ast.to_node(self.upcast());
-                        (InFile::new(ast.file_id, node.syntax().clone()), "UnresolvedMacroCall")
-                    }
-                    DefDiagnosticKind::MacroError { ast, message } => {
-                        (ast.to_node(self.upcast()), message.as_str())
-                    }
-                    DefDiagnosticKind::UnimplementedBuiltinMacro { ast } => {
-                        let node = ast.to_node(self.upcast());
-                        (
-                            InFile::new(ast.file_id, node.syntax().clone()),
-                            "UnimplementedBuiltinMacro",
-                        )
-                    }
-                };
-
-                let frange = node.as_ref().original_file_range(self);
-                cb(frange, message.to_string())
-            }
-
-            for (_module_id, module) in crate_def_map.modules() {
-                for decl in module.scope.declarations() {
-                    if let ModuleDefId::FunctionId(it) = decl {
-                        let source_map = self.body_with_source_map(it.into()).1;
-                        for diag in source_map.diagnostics() {
-                            let (ptr, message): (InFile<SyntaxNodePtr>, &str) = match diag {
-                                BodyDiagnostic::InactiveCode { node, .. } => {
-                                    (node.clone().map(|it| it.into()), "InactiveCode")
-                                }
-                                BodyDiagnostic::MacroError { node, message } => {
-                                    (node.clone().map(|it| it.into()), message.as_str())
-                                }
-                                BodyDiagnostic::UnresolvedProcMacro { node } => {
-                                    (node.clone().map(|it| it.into()), "UnresolvedProcMacro")
-                                }
-                                BodyDiagnostic::UnresolvedMacroCall { node, .. } => {
-                                    (node.clone().map(|it| it.into()), "UnresolvedMacroCall")
-                                }
-                            };
-
-                            let root = self.parse_or_expand(ptr.file_id).unwrap();
-                            let node = ptr.map(|ptr| ptr.to_node(&root));
-                            let frange = node.as_ref().original_file_range(self);
-                            cb(frange, message.to_string())
-                        }
-                    }
-                }
-            }
-        }
-    }
-
-    pub(crate) fn check_diagnostics(&self) {
-        let db: &TestDB = self;
-        let annotations = db.extract_annotations();
-        assert!(!annotations.is_empty());
-
-        let mut actual: FxHashMap<FileId, Vec<(TextRange, String)>> = FxHashMap::default();
-        db.diagnostics(&mut |frange, message| {
-            actual.entry(frange.file_id).or_default().push((frange.range, message));
-        });
-
-        for (file_id, diags) in actual.iter_mut() {
-            diags.sort_by_key(|it| it.0.start());
-            let text = db.file_text(*file_id);
-            // For multiline spans, place them on line start
-            for (range, content) in diags {
-                if text[*range].contains('\n') {
-                    *range = TextRange::new(range.start(), range.start() + TextSize::from(1));
-                    *content = format!("... {}", content);
-                }
-            }
-        }
-
-        assert_eq!(annotations, actual);
-    }
-
-    pub(crate) fn check_no_diagnostics(&self) {
-        let db: &TestDB = self;
-        let annotations = db.extract_annotations();
-        assert!(annotations.is_empty());
-
-        let mut has_diagnostics = false;
-        db.diagnostics(&mut |_, _| {
-            has_diagnostics = true;
-        });
-
-        assert!(!has_diagnostics);
-    }
 }
diff --git a/crates/hir_def/src/type_ref.rs b/crates/hir_def/src/type_ref.rs
index cbde6b940..ffe499973 100644
--- a/crates/hir_def/src/type_ref.rs
+++ b/crates/hir_def/src/type_ref.rs
@@ -128,7 +128,7 @@ impl TypeRef {
     /// Converts an `ast::TypeRef` to a `hir::TypeRef`.
     pub fn from_ast(ctx: &LowerCtx, node: ast::Type) -> Self {
         match node {
-            ast::Type::ParenType(inner) => TypeRef::from_ast_opt(&ctx, inner.ty()),
+            ast::Type::ParenType(inner) => TypeRef::from_ast_opt(ctx, inner.ty()),
             ast::Type::TupleType(inner) => {
                 TypeRef::Tuple(inner.fields().map(|it| TypeRef::from_ast(ctx, it)).collect())
             }
@@ -142,7 +142,7 @@ impl TypeRef {
                     .unwrap_or(TypeRef::Error)
             }
             ast::Type::PtrType(inner) => {
-                let inner_ty = TypeRef::from_ast_opt(&ctx, inner.ty());
+                let inner_ty = TypeRef::from_ast_opt(ctx, inner.ty());
                 let mutability = Mutability::from_mutable(inner.mut_token().is_some());
                 TypeRef::RawPtr(Box::new(inner_ty), mutability)
             }
@@ -156,13 +156,13 @@ impl TypeRef {
                     .map(ConstScalar::usize_from_literal_expr)
                     .unwrap_or(ConstScalar::Unknown);
 
-                TypeRef::Array(Box::new(TypeRef::from_ast_opt(&ctx, inner.ty())), len)
+                TypeRef::Array(Box::new(TypeRef::from_ast_opt(ctx, inner.ty())), len)
             }
             ast::Type::SliceType(inner) => {
-                TypeRef::Slice(Box::new(TypeRef::from_ast_opt(&ctx, inner.ty())))
+                TypeRef::Slice(Box::new(TypeRef::from_ast_opt(ctx, inner.ty())))
             }
             ast::Type::RefType(inner) => {
-                let inner_ty = TypeRef::from_ast_opt(&ctx, inner.ty());
+                let inner_ty = TypeRef::from_ast_opt(ctx, inner.ty());
                 let lifetime = inner.lifetime().map(|lt| LifetimeRef::new(&lt));
                 let mutability = Mutability::from_mutable(inner.mut_token().is_some());
                 TypeRef::Reference(Box::new(inner_ty), lifetime, mutability)
@@ -180,7 +180,7 @@ impl TypeRef {
                         is_varargs = param.dotdotdot_token().is_some();
                     }
 
-                    pl.params().map(|p| p.ty()).map(|it| TypeRef::from_ast_opt(&ctx, it)).collect()
+                    pl.params().map(|p| p.ty()).map(|it| TypeRef::from_ast_opt(ctx, it)).collect()
                 } else {
                     Vec::new()
                 };
@@ -188,7 +188,7 @@ impl TypeRef {
                 TypeRef::Fn(params, is_varargs)
             }
             // for types are close enough for our purposes to the inner type for now...
-            ast::Type::ForType(inner) => TypeRef::from_ast_opt(&ctx, inner.ty()),
+            ast::Type::ForType(inner) => TypeRef::from_ast_opt(ctx, inner.ty()),
             ast::Type::ImplTraitType(inner) => {
                 TypeRef::ImplTrait(type_bounds_from_ast(ctx, inner.type_bound_list()))
             }
@@ -229,7 +229,7 @@ impl TypeRef {
                 TypeRef::RawPtr(type_ref, _)
                 | TypeRef::Reference(type_ref, ..)
                 | TypeRef::Array(type_ref, _)
-                | TypeRef::Slice(type_ref) => go(&type_ref, f),
+                | TypeRef::Slice(type_ref) => go(type_ref, f),
                 TypeRef::ImplTrait(bounds) | TypeRef::DynTrait(bounds) => {
                     for bound in bounds {
                         match bound.as_ref() {
diff --git a/crates/hir_expand/src/builtin_derive.rs b/crates/hir_expand/src/builtin_derive.rs
index fe9497b50..4610f6f91 100644
--- a/crates/hir_expand/src/builtin_derive.rs
+++ b/crates/hir_expand/src/builtin_derive.rs
@@ -325,7 +325,7 @@ $0
             },
         };
 
-        let id: MacroCallId = db.intern_macro(loc).into();
+        let id: MacroCallId = db.intern_macro(loc);
         let parsed = db.parse_or_expand(id.as_file()).unwrap();
 
         // FIXME text() for syntax nodes parsed from token tree looks weird
diff --git a/crates/hir_expand/src/builtin_macro.rs b/crates/hir_expand/src/builtin_macro.rs
index 0b310ba2f..f24d1d919 100644
--- a/crates/hir_expand/src/builtin_macro.rs
+++ b/crates/hir_expand/src/builtin_macro.rs
@@ -354,7 +354,7 @@ fn concat_expand(
                 // concat works with string and char literals, so remove any quotes.
                 // It also works with integer, float and boolean literals, so just use the rest
                 // as-is.
-                let component = unquote_str(&it).unwrap_or_else(|| it.text.to_string());
+                let component = unquote_str(it).unwrap_or_else(|| it.text.to_string());
                 text.push_str(&component);
             }
             // handle boolean literals
@@ -417,7 +417,7 @@ fn parse_string(tt: &tt::Subtree) -> Result<String, mbe::ExpandError> {
     tt.token_trees
         .get(0)
         .and_then(|tt| match tt {
-            tt::TokenTree::Leaf(tt::Leaf::Literal(it)) => unquote_str(&it),
+            tt::TokenTree::Leaf(tt::Leaf::Literal(it)) => unquote_str(it),
             _ => None,
         })
         .ok_or_else(|| mbe::ExpandError::ConversionError)
@@ -430,7 +430,7 @@ fn include_expand(
 ) -> ExpandResult<Option<ExpandedEager>> {
     let res = (|| {
         let path = parse_string(tt)?;
-        let file_id = relative_file(db, arg_id.into(), &path, false)?;
+        let file_id = relative_file(db, arg_id, &path, false)?;
 
         let subtree = parse_to_token_tree(&db.file_text(file_id))
             .ok_or_else(|| mbe::ExpandError::ConversionError)?
@@ -480,7 +480,7 @@ fn include_str_expand(
     // it's unusual to `include_str!` a Rust file), but we can return an empty string.
     // Ideally, we'd be able to offer a precise expansion if the user asks for macro
     // expansion.
-    let file_id = match relative_file(db, arg_id.into(), &path, true) {
+    let file_id = match relative_file(db, arg_id, &path, true) {
         Ok(file_id) => file_id,
         Err(_) => {
             return ExpandResult::ok(Some(ExpandedEager::new(quote!(""))));
@@ -561,7 +561,7 @@ mod tests {
     use syntax::ast::NameOwner;
 
     fn expand_builtin_macro(ra_fixture: &str) -> String {
-        let (db, file_id) = TestDB::with_single_file(&ra_fixture);
+        let (db, file_id) = TestDB::with_single_file(ra_fixture);
         let parsed = db.parse(file_id);
         let mut macro_rules: Vec<_> =
             parsed.syntax_node().descendants().filter_map(ast::MacroRules::cast).collect();
@@ -598,7 +598,7 @@ mod tests {
                     },
                 };
 
-                let id: MacroCallId = db.intern_macro(loc).into();
+                let id: MacroCallId = db.intern_macro(loc);
                 id.as_file()
             }
             Either::Right(expander) => {
@@ -635,7 +635,7 @@ mod tests {
                     kind: MacroCallKind::FnLike { ast_id: call_id, fragment },
                 };
 
-                let id: MacroCallId = db.intern_macro(loc).into();
+                let id: MacroCallId = db.intern_macro(loc);
                 id.as_file()
             }
         };
diff --git a/crates/hir_expand/src/db.rs b/crates/hir_expand/src/db.rs
index 45e6e446a..66f44202b 100644
--- a/crates/hir_expand/src/db.rs
+++ b/crates/hir_expand/src/db.rs
@@ -57,7 +57,7 @@ impl TokenExpander {
                 // We store the result in salsa db to prevent non-deterministic behavior in
                 // some proc-macro implementation
                 // See #4315 for details
-                db.expand_proc_macro(id.into()).into()
+                db.expand_proc_macro(id).into()
             }
         }
     }
@@ -241,7 +241,7 @@ fn parse_macro_expansion(
                 }
             };
             if is_self_replicating(&node, &call_node.value) {
-                return ExpandResult::only_err(err);
+                ExpandResult::only_err(err)
             } else {
                 ExpandResult { value: Some((parse, Arc::new(rev_token_map))), err: Some(err) }
             }
diff --git a/crates/hir_expand/src/eager.rs b/crates/hir_expand/src/eager.rs
index 9093255f4..584ddcf9f 100644
--- a/crates/hir_expand/src/eager.rs
+++ b/crates/hir_expand/src/eager.rs
@@ -17,7 +17,7 @@
 //! > and we need to live with it because it's available on stable and widely relied upon.
 //!
 //!
-//! See the full discussion : https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Eager.20expansion.20of.20built-in.20macros
+//! See the full discussion : <https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Eager.20expansion.20of.20built-in.20macros>
 
 use crate::{
     ast::{self, AstNode},
@@ -128,7 +128,7 @@ pub fn expand_eager_macro(
         }),
         kind: MacroCallKind::FnLike { ast_id: call_id, fragment: FragmentKind::Expr },
     });
-    let arg_file_id: MacroCallId = arg_id.into();
+    let arg_file_id: MacroCallId = arg_id;
 
     let parsed_args =
         diagnostic_sink.result(mbe::token_tree_to_syntax_node(&parsed_args, FragmentKind::Expr))?.0;
@@ -177,13 +177,11 @@ fn lazy_expand(
     let ast_id = db.ast_id_map(macro_call.file_id).ast_id(&macro_call.value);
 
     let fragment = crate::to_fragment_kind(&macro_call.value);
-    let id: MacroCallId = def
-        .as_lazy_macro(
-            db,
-            krate,
-            MacroCallKind::FnLike { ast_id: macro_call.with_value(ast_id), fragment },
-        )
-        .into();
+    let id: MacroCallId = def.as_lazy_macro(
+        db,
+        krate,
+        MacroCallKind::FnLike { ast_id: macro_call.with_value(ast_id), fragment },
+    );
 
     let err = db.macro_expand_error(id);
     let value = db.parse_or_expand(id.as_file()).map(|node| InFile::new(id.as_file(), node));
@@ -216,8 +214,7 @@ fn eager_macro_recur(
                     def,
                     macro_resolver,
                     diagnostic_sink,
-                )?
-                .into();
+                )?;
                 db.parse_or_expand(id.as_file())
                     .expect("successful macro expansion should be parseable")
                     .clone_for_update()
diff --git a/crates/hir_expand/src/input.rs b/crates/hir_expand/src/input.rs
index 82dc7f326..bc3ecc593 100644
--- a/crates/hir_expand/src/input.rs
+++ b/crates/hir_expand/src/input.rs
@@ -78,7 +78,7 @@ mod tests {
     use super::*;
 
     fn test_remove_derives_up_to(attr: usize, ra_fixture: &str, expect: Expect) {
-        let (db, file_id) = TestDB::with_single_file(&ra_fixture);
+        let (db, file_id) = TestDB::with_single_file(ra_fixture);
         let parsed = db.parse(file_id);
 
         let mut items: Vec<_> =
diff --git a/crates/hir_expand/src/lib.rs b/crates/hir_expand/src/lib.rs
index 623791b58..33107aa24 100644
--- a/crates/hir_expand/src/lib.rs
+++ b/crates/hir_expand/src/lib.rs
@@ -53,7 +53,7 @@ mod test_db;
 /// this is a recursive definition! However, the size_of of `HirFileId` is
 /// finite (because everything bottoms out at the real `FileId`) and small
 /// (`MacroCallId` uses the location interning. You can check details here:
-/// https://en.wikipedia.org/wiki/String_interning).
+/// <https://en.wikipedia.org/wiki/String_interning>).
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct HirFileId(HirFileIdRepr);
 
diff --git a/crates/hir_expand/src/proc_macro.rs b/crates/hir_expand/src/proc_macro.rs
index dbe1b446e..025e10239 100644
--- a/crates/hir_expand/src/proc_macro.rs
+++ b/crates/hir_expand/src/proc_macro.rs
@@ -45,13 +45,12 @@ impl ProcMacroExpander {
                 let proc_macro = krate_graph[self.krate]
                     .proc_macro
                     .get(id.0 as usize)
-                    .clone()
                     .ok_or_else(|| err!("No derive macro found."))?;
 
                 // Proc macros have access to the environment variables of the invoking crate.
                 let env = &krate_graph[calling_crate].env;
 
-                proc_macro.expander.expand(&tt, attr_arg, &env).map_err(mbe::ExpandError::from)
+                proc_macro.expander.expand(tt, attr_arg, env).map_err(mbe::ExpandError::from)
             }
             None => Err(mbe::ExpandError::UnresolvedProcMacro),
         }
diff --git a/crates/hir_ty/Cargo.toml b/crates/hir_ty/Cargo.toml
index 4b714c6d8..74129eb21 100644
--- a/crates/hir_ty/Cargo.toml
+++ b/crates/hir_ty/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = { version = "1.1", features = ["thread-local"] }
+cov-mark = "2.0.0-pre.1"
 itertools = "0.10.0"
 arrayvec = "0.7"
 smallvec = "1.2.0"
@@ -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/builder.rs b/crates/hir_ty/src/builder.rs
index 893e727c2..bb9d84246 100644
--- a/crates/hir_ty/src/builder.rs
+++ b/crates/hir_ty/src/builder.rs
@@ -202,7 +202,7 @@ impl<T: HasInterner<Interner = Interner> + Fold<Interner>> TyBuilder<Binders<T>>
 
 impl TyBuilder<Binders<Ty>> {
     pub fn def_ty(db: &dyn HirDatabase, def: TyDefId) -> TyBuilder<Binders<Ty>> {
-        TyBuilder::subst_binders(db.ty(def.into()))
+        TyBuilder::subst_binders(db.ty(def))
     }
 
     pub fn impl_self_ty(db: &dyn HirDatabase, def: hir_def::ImplId) -> TyBuilder<Binders<Ty>> {
diff --git a/crates/hir_ty/src/chalk_db.rs b/crates/hir_ty/src/chalk_db.rs
index 4e042bf42..a4c09c742 100644
--- a/crates/hir_ty/src/chalk_db.rs
+++ b/crates/hir_ty/src/chalk_db.rs
@@ -10,16 +10,16 @@ use chalk_solve::rust_ir::{self, OpaqueTyDatumBound, WellKnownTrait};
 use base_db::CrateId;
 use hir_def::{
     lang_item::{lang_attr, LangItemTarget},
-    AssocContainerId, AssocItemId, GenericDefId, HasModule, Lookup, TypeAliasId,
+    AssocContainerId, AssocItemId, GenericDefId, HasModule, Lookup, ModuleId, TypeAliasId,
 };
 use hir_expand::name::name;
 
 use crate::{
     db::HirDatabase,
     display::HirDisplay,
-    from_assoc_type_id, from_chalk_trait_id, make_only_type_binders,
+    from_assoc_type_id, from_chalk_trait_id, from_foreign_def_id, make_only_type_binders,
     mapping::{from_chalk, ToChalk, TypeAliasAsValue},
-    method_resolution::{TyFingerprint, ALL_FLOAT_FPS, ALL_INT_FPS},
+    method_resolution::{TraitImpls, TyFingerprint, ALL_FLOAT_FPS, ALL_INT_FPS},
     to_assoc_type_id, to_chalk_trait_id,
     traits::ChalkContext,
     utils::generics,
@@ -105,12 +105,30 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
             _ => self_ty_fp.as_ref().map(std::slice::from_ref).unwrap_or(&[]),
         };
 
+        fn local_impls(db: &dyn HirDatabase, module: ModuleId) -> Option<Arc<TraitImpls>> {
+            db.trait_impls_in_block(module.containing_block()?)
+        }
+
         // Note: Since we're using impls_for_trait, only impls where the trait
-        // can be resolved should ever reach Chalk. Symbol’s value as variable is void: impl_datum relies on that
+        // can be resolved should ever reach Chalk. impl_datum relies on that
         // and will panic if the trait can't be resolved.
         let in_deps = self.db.trait_impls_in_deps(self.krate);
         let in_self = self.db.trait_impls_in_crate(self.krate);
-        let impl_maps = [in_deps, in_self];
+        let trait_module = trait_.module(self.db.upcast());
+        let type_module = match self_ty_fp {
+            Some(TyFingerprint::Adt(adt_id)) => Some(adt_id.module(self.db.upcast())),
+            Some(TyFingerprint::ForeignType(type_id)) => {
+                Some(from_foreign_def_id(type_id).module(self.db.upcast()))
+            }
+            Some(TyFingerprint::Dyn(trait_id)) => Some(trait_id.module(self.db.upcast())),
+            _ => None,
+        };
+        let impl_maps = [
+            Some(in_deps),
+            Some(in_self),
+            local_impls(self.db, trait_module),
+            type_module.and_then(|m| local_impls(self.db, m)),
+        ];
 
         let id_to_chalk = |id: hir_def::ImplId| id.to_chalk(self.db);
 
@@ -118,14 +136,16 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
             debug!("Unrestricted search for {:?} impls...", trait_);
             impl_maps
                 .iter()
-                .flat_map(|crate_impl_defs| crate_impl_defs.for_trait(trait_).map(id_to_chalk))
+                .filter_map(|o| o.as_ref())
+                .flat_map(|impls| impls.for_trait(trait_).map(id_to_chalk))
                 .collect()
         } else {
             impl_maps
                 .iter()
-                .flat_map(|crate_impl_defs| {
+                .filter_map(|o| o.as_ref())
+                .flat_map(|impls| {
                     fps.iter().flat_map(move |fp| {
-                        crate_impl_defs.for_trait_and_self_ty(trait_, *fp).map(id_to_chalk)
+                        impls.for_trait_and_self_ty(trait_, *fp).map(id_to_chalk)
                     })
                 })
                 .collect()
@@ -430,8 +450,7 @@ pub(crate) fn trait_datum_query(
         fundamental: false,
     };
     let where_clauses = convert_where_clauses(db, trait_.into(), &bound_vars);
-    let associated_ty_ids =
-        trait_data.associated_types().map(|type_alias| to_assoc_type_id(type_alias)).collect();
+    let associated_ty_ids = trait_data.associated_types().map(to_assoc_type_id).collect();
     let trait_datum_bound = rust_ir::TraitDatumBound { where_clauses };
     let well_known =
         lang_attr(db.upcast(), trait_).and_then(|name| well_known_trait_from_lang_attr(&name));
diff --git a/crates/hir_ty/src/consteval.rs b/crates/hir_ty/src/consteval.rs
index e3ceb3d62..6f0bf8f8c 100644
--- a/crates/hir_ty/src/consteval.rs
+++ b/crates/hir_ty/src/consteval.rs
@@ -49,7 +49,7 @@ pub fn usize_const(value: Option<u64>) -> Const {
     ConstData {
         ty: TyKind::Scalar(chalk_ir::Scalar::Uint(chalk_ir::UintTy::Usize)).intern(&Interner),
         value: ConstValue::Concrete(chalk_ir::ConcreteConst {
-            interned: value.map(|value| ConstScalar::Usize(value)).unwrap_or(ConstScalar::Unknown),
+            interned: value.map(ConstScalar::Usize).unwrap_or(ConstScalar::Unknown),
         }),
     }
     .intern(&Interner)
diff --git a/crates/hir_ty/src/db.rs b/crates/hir_ty/src/db.rs
index be5b9110e..b9003c413 100644
--- a/crates/hir_ty/src/db.rs
+++ b/crates/hir_ty/src/db.rs
@@ -5,8 +5,8 @@ use std::sync::Arc;
 
 use base_db::{impl_intern_key, salsa, CrateId, Upcast};
 use hir_def::{
-    db::DefDatabase, expr::ExprId, ConstParamId, DefWithBodyId, FunctionId, GenericDefId, ImplId,
-    LifetimeParamId, LocalFieldId, TypeParamId, VariantId,
+    db::DefDatabase, expr::ExprId, BlockId, ConstParamId, DefWithBodyId, FunctionId, GenericDefId,
+    ImplId, LifetimeParamId, LocalFieldId, TypeParamId, VariantId,
 };
 use la_arena::ArenaMap;
 
@@ -79,6 +79,9 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     #[salsa::invoke(TraitImpls::trait_impls_in_crate_query)]
     fn trait_impls_in_crate(&self, krate: CrateId) -> Arc<TraitImpls>;
 
+    #[salsa::invoke(TraitImpls::trait_impls_in_block_query)]
+    fn trait_impls_in_block(&self, krate: BlockId) -> Option<Arc<TraitImpls>>;
+
     #[salsa::invoke(TraitImpls::trait_impls_in_deps_query)]
     fn trait_impls_in_deps(&self, krate: CrateId) -> Arc<TraitImpls>;
 
diff --git a/crates/hir_ty/src/diagnostics.rs b/crates/hir_ty/src/diagnostics.rs
index 283894704..6339c9687 100644
--- a/crates/hir_ty/src/diagnostics.rs
+++ b/crates/hir_ty/src/diagnostics.rs
@@ -4,325 +4,31 @@ mod match_check;
 mod unsafe_check;
 mod decl_check;
 
-use std::{any::Any, fmt};
+use std::fmt;
 
 use base_db::CrateId;
-use hir_def::{DefWithBodyId, ModuleDefId};
-use hir_expand::{name::Name, HirFileId, InFile};
-use stdx::format_to;
-use syntax::{ast, AstPtr, SyntaxNodePtr};
+use hir_def::ModuleDefId;
+use hir_expand::HirFileId;
+use syntax::{ast, AstPtr};
 
-use crate::{
-    db::HirDatabase,
-    diagnostics_sink::{Diagnostic, DiagnosticCode, DiagnosticSink},
-};
+use crate::db::HirDatabase;
 
-pub use crate::diagnostics::expr::{record_literal_missing_fields, record_pattern_missing_fields};
+pub use crate::diagnostics::{
+    expr::{
+        record_literal_missing_fields, record_pattern_missing_fields, BodyValidationDiagnostic,
+    },
+    unsafe_check::missing_unsafe,
+};
 
 pub fn validate_module_item(
     db: &dyn HirDatabase,
     krate: CrateId,
     owner: ModuleDefId,
-    sink: &mut DiagnosticSink<'_>,
-) {
+) -> Vec<IncorrectCase> {
     let _p = profile::span("validate_module_item");
-    let mut validator = decl_check::DeclValidator::new(db, krate, sink);
+    let mut validator = decl_check::DeclValidator::new(db, krate);
     validator.validate_item(owner);
-}
-
-pub fn validate_body(db: &dyn HirDatabase, owner: DefWithBodyId, sink: &mut DiagnosticSink<'_>) {
-    let _p = profile::span("validate_body");
-    let infer = db.infer(owner);
-    infer.add_diagnostics(db, owner, sink);
-    let mut validator = expr::ExprValidator::new(owner, infer.clone(), sink);
-    validator.validate_body(db);
-    let mut validator = unsafe_check::UnsafeValidator::new(owner, infer, sink);
-    validator.validate_body(db);
-}
-
-// Diagnostic: no-such-field
-//
-// This diagnostic is triggered if created structure does not have field provided in record.
-#[derive(Debug)]
-pub struct NoSuchField {
-    pub file: HirFileId,
-    pub field: AstPtr<ast::RecordExprField>,
-}
-
-impl Diagnostic for NoSuchField {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("no-such-field")
-    }
-
-    fn message(&self) -> String {
-        "no such field".to_string()
-    }
-
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile::new(self.file, self.field.clone().into())
-    }
-
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-}
-
-// Diagnostic: missing-structure-fields
-//
-// This diagnostic is triggered if record lacks some fields that exist in the corresponding structure.
-//
-// Example:
-//
-// ```rust
-// struct A { a: u8, b: u8 }
-//
-// let a = A { a: 10 };
-// ```
-#[derive(Debug)]
-pub struct MissingFields {
-    pub file: HirFileId,
-    pub field_list_parent: AstPtr<ast::RecordExpr>,
-    pub field_list_parent_path: Option<AstPtr<ast::Path>>,
-    pub missed_fields: Vec<Name>,
-}
-
-impl Diagnostic for MissingFields {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("missing-structure-fields")
-    }
-    fn message(&self) -> String {
-        let mut buf = String::from("Missing structure fields:\n");
-        for field in &self.missed_fields {
-            format_to!(buf, "- {}\n", field);
-        }
-        buf
-    }
-
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile {
-            file_id: self.file,
-            value: self
-                .field_list_parent_path
-                .clone()
-                .map(SyntaxNodePtr::from)
-                .unwrap_or_else(|| self.field_list_parent.clone().into()),
-        }
-    }
-
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-}
-
-// Diagnostic: missing-pat-fields
-//
-// This diagnostic is triggered if pattern lacks some fields that exist in the corresponding structure.
-//
-// Example:
-//
-// ```rust
-// struct A { a: u8, b: u8 }
-//
-// let a = A { a: 10, b: 20 };
-//
-// if let A { a } = a {
-//     // ...
-// }
-// ```
-#[derive(Debug)]
-pub struct MissingPatFields {
-    pub file: HirFileId,
-    pub field_list_parent: AstPtr<ast::RecordPat>,
-    pub field_list_parent_path: Option<AstPtr<ast::Path>>,
-    pub missed_fields: Vec<Name>,
-}
-
-impl Diagnostic for MissingPatFields {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("missing-pat-fields")
-    }
-    fn message(&self) -> String {
-        let mut buf = String::from("Missing structure fields:\n");
-        for field in &self.missed_fields {
-            format_to!(buf, "- {}\n", field);
-        }
-        buf
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile {
-            file_id: self.file,
-            value: self
-                .field_list_parent_path
-                .clone()
-                .map(SyntaxNodePtr::from)
-                .unwrap_or_else(|| self.field_list_parent.clone().into()),
-        }
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-}
-
-// Diagnostic: missing-match-arm
-//
-// This diagnostic is triggered if `match` block is missing one or more match arms.
-#[derive(Debug)]
-pub struct MissingMatchArms {
-    pub file: HirFileId,
-    pub match_expr: AstPtr<ast::Expr>,
-    pub arms: AstPtr<ast::MatchArmList>,
-}
-
-impl Diagnostic for MissingMatchArms {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("missing-match-arm")
-    }
-    fn message(&self) -> String {
-        String::from("Missing match arm")
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile { file_id: self.file, value: self.match_expr.clone().into() }
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-}
-
-// Diagnostic: missing-ok-or-some-in-tail-expr
-//
-// This diagnostic is triggered if a block that should return `Result` returns a value not wrapped in `Ok`,
-// or if a block that should return `Option` returns a value not wrapped in `Some`.
-//
-// Example:
-//
-// ```rust
-// fn foo() -> Result<u8, ()> {
-//     10
-// }
-// ```
-#[derive(Debug)]
-pub struct MissingOkOrSomeInTailExpr {
-    pub file: HirFileId,
-    pub expr: AstPtr<ast::Expr>,
-    // `Some` or `Ok` depending on whether the return type is Result or Option
-    pub required: String,
-}
-
-impl Diagnostic for MissingOkOrSomeInTailExpr {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("missing-ok-or-some-in-tail-expr")
-    }
-    fn message(&self) -> String {
-        format!("wrap return expression in {}", self.required)
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile { file_id: self.file, value: self.expr.clone().into() }
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-}
-
-#[derive(Debug)]
-pub struct RemoveThisSemicolon {
-    pub file: HirFileId,
-    pub expr: AstPtr<ast::Expr>,
-}
-
-impl Diagnostic for RemoveThisSemicolon {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("remove-this-semicolon")
-    }
-
-    fn message(&self) -> String {
-        "Remove this semicolon".to_string()
-    }
-
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile { file_id: self.file, value: self.expr.clone().into() }
-    }
-
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-}
-
-// Diagnostic: break-outside-of-loop
-//
-// This diagnostic is triggered if the `break` keyword is used outside of a loop.
-#[derive(Debug)]
-pub struct BreakOutsideOfLoop {
-    pub file: HirFileId,
-    pub expr: AstPtr<ast::Expr>,
-}
-
-impl Diagnostic for BreakOutsideOfLoop {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("break-outside-of-loop")
-    }
-    fn message(&self) -> String {
-        "break outside of loop".to_string()
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile { file_id: self.file, value: self.expr.clone().into() }
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-}
-
-// Diagnostic: missing-unsafe
-//
-// This diagnostic is triggered if an operation marked as `unsafe` is used outside of an `unsafe` function or block.
-#[derive(Debug)]
-pub struct MissingUnsafe {
-    pub file: HirFileId,
-    pub expr: AstPtr<ast::Expr>,
-}
-
-impl Diagnostic for MissingUnsafe {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("missing-unsafe")
-    }
-    fn message(&self) -> String {
-        format!("This operation is unsafe and requires an unsafe function or block")
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile { file_id: self.file, value: self.expr.clone().into() }
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-}
-
-// Diagnostic: mismatched-arg-count
-//
-// This diagnostic is triggered if a function is invoked with an incorrect amount of arguments.
-#[derive(Debug)]
-pub struct MismatchedArgCount {
-    pub file: HirFileId,
-    pub call_expr: AstPtr<ast::Expr>,
-    pub expected: usize,
-    pub found: usize,
-}
-
-impl Diagnostic for MismatchedArgCount {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("mismatched-arg-count")
-    }
-    fn message(&self) -> String {
-        let s = if self.expected == 1 { "" } else { "s" };
-        format!("Expected {} argument{}, found {}", self.expected, s, self.found)
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile { file_id: self.file, value: self.call_expr.clone().into() }
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-    fn is_experimental(&self) -> bool {
-        true
-    }
+    validator.sink
 }
 
 #[derive(Debug)]
@@ -378,9 +84,6 @@ impl fmt::Display for IdentType {
     }
 }
 
-// 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].
 #[derive(Debug)]
 pub struct IncorrectCase {
     pub file: HirFileId,
@@ -390,450 +93,3 @@ pub struct IncorrectCase {
     pub ident_text: String,
     pub suggested_text: String,
 }
-
-impl Diagnostic for IncorrectCase {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("incorrect-ident-case")
-    }
-
-    fn message(&self) -> String {
-        format!(
-            "{} `{}` should have {} name, e.g. `{}`",
-            self.ident_type,
-            self.ident_text,
-            self.expected_case.to_string(),
-            self.suggested_text
-        )
-    }
-
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile::new(self.file, self.ident.clone().into())
-    }
-
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-
-    fn is_experimental(&self) -> bool {
-        true
-    }
-}
-
-// 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(..)`.
-#[derive(Debug)]
-pub struct ReplaceFilterMapNextWithFindMap {
-    pub file: HirFileId,
-    /// This expression is the whole method chain up to and including `.filter_map(..).next()`.
-    pub next_expr: AstPtr<ast::Expr>,
-}
-
-impl Diagnostic for ReplaceFilterMapNextWithFindMap {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("replace-filter-map-next-with-find-map")
-    }
-    fn message(&self) -> String {
-        "replace filter_map(..).next() with find_map(..)".to_string()
-    }
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile { file_id: self.file, value: self.next_expr.clone().into() }
-    }
-    fn as_any(&self) -> &(dyn Any + Send + 'static) {
-        self
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use base_db::{fixture::WithFixture, FileId, SourceDatabase, SourceDatabaseExt};
-    use hir_def::{db::DefDatabase, AssocItemId, ModuleDefId};
-    use hir_expand::db::AstDatabase;
-    use rustc_hash::FxHashMap;
-    use syntax::{TextRange, TextSize};
-
-    use crate::{
-        diagnostics::{validate_body, validate_module_item},
-        diagnostics_sink::{Diagnostic, DiagnosticSinkBuilder},
-        test_db::TestDB,
-    };
-
-    impl TestDB {
-        fn diagnostics<F: FnMut(&dyn Diagnostic)>(&self, mut cb: F) {
-            let crate_graph = self.crate_graph();
-            for krate in crate_graph.iter() {
-                let crate_def_map = self.crate_def_map(krate);
-
-                let mut fns = Vec::new();
-                for (module_id, _) in crate_def_map.modules() {
-                    for decl in crate_def_map[module_id].scope.declarations() {
-                        let mut sink = DiagnosticSinkBuilder::new().build(&mut cb);
-                        validate_module_item(self, krate, decl, &mut sink);
-
-                        if let ModuleDefId::FunctionId(f) = decl {
-                            fns.push(f)
-                        }
-                    }
-
-                    for impl_id in crate_def_map[module_id].scope.impls() {
-                        let impl_data = self.impl_data(impl_id);
-                        for item in impl_data.items.iter() {
-                            if let AssocItemId::FunctionId(f) = item {
-                                let mut sink = DiagnosticSinkBuilder::new().build(&mut cb);
-                                validate_module_item(
-                                    self,
-                                    krate,
-                                    ModuleDefId::FunctionId(*f),
-                                    &mut sink,
-                                );
-                                fns.push(*f)
-                            }
-                        }
-                    }
-                }
-
-                for f in fns {
-                    let mut sink = DiagnosticSinkBuilder::new().build(&mut cb);
-                    validate_body(self, f.into(), &mut sink);
-                }
-            }
-        }
-    }
-
-    pub(crate) fn check_diagnostics(ra_fixture: &str) {
-        let db = TestDB::with_files(ra_fixture);
-        let annotations = db.extract_annotations();
-
-        let mut actual: FxHashMap<FileId, Vec<(TextRange, String)>> = FxHashMap::default();
-        db.diagnostics(|d| {
-            let src = d.display_source();
-            let root = db.parse_or_expand(src.file_id).unwrap();
-            // FIXME: macros...
-            let file_id = src.file_id.original_file(&db);
-            let range = src.value.to_node(&root).text_range();
-            let message = d.message();
-            actual.entry(file_id).or_default().push((range, message));
-        });
-
-        for (file_id, diags) in actual.iter_mut() {
-            diags.sort_by_key(|it| it.0.start());
-            let text = db.file_text(*file_id);
-            // For multiline spans, place them on line start
-            for (range, content) in diags {
-                if text[*range].contains('\n') {
-                    *range = TextRange::new(range.start(), range.start() + TextSize::from(1));
-                    *content = format!("... {}", content);
-                }
-            }
-        }
-
-        assert_eq!(annotations, actual);
-    }
-
-    #[test]
-    fn no_such_field_diagnostics() {
-        check_diagnostics(
-            r#"
-struct S { foo: i32, bar: () }
-impl S {
-    fn new() -> S {
-        S {
-      //^ Missing structure fields:
-      //|    - bar
-            foo: 92,
-            baz: 62,
-          //^^^^^^^ no such field
-        }
-    }
-}
-"#,
-        );
-    }
-    #[test]
-    fn no_such_field_with_feature_flag_diagnostics() {
-        check_diagnostics(
-            r#"
-//- /lib.rs crate:foo cfg:feature=foo
-struct MyStruct {
-    my_val: usize,
-    #[cfg(feature = "foo")]
-    bar: bool,
-}
-
-impl MyStruct {
-    #[cfg(feature = "foo")]
-    pub(crate) fn new(my_val: usize, bar: bool) -> Self {
-        Self { my_val, bar }
-    }
-    #[cfg(not(feature = "foo"))]
-    pub(crate) fn new(my_val: usize, _bar: bool) -> Self {
-        Self { my_val }
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn no_such_field_enum_with_feature_flag_diagnostics() {
-        check_diagnostics(
-            r#"
-//- /lib.rs crate:foo cfg:feature=foo
-enum Foo {
-    #[cfg(not(feature = "foo"))]
-    Buz,
-    #[cfg(feature = "foo")]
-    Bar,
-    Baz
-}
-
-fn test_fn(f: Foo) {
-    match f {
-        Foo::Bar => {},
-        Foo::Baz => {},
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn no_such_field_with_feature_flag_diagnostics_on_struct_lit() {
-        check_diagnostics(
-            r#"
-//- /lib.rs crate:foo cfg:feature=foo
-struct S {
-    #[cfg(feature = "foo")]
-    foo: u32,
-    #[cfg(not(feature = "foo"))]
-    bar: u32,
-}
-
-impl S {
-    #[cfg(feature = "foo")]
-    fn new(foo: u32) -> Self {
-        Self { foo }
-    }
-    #[cfg(not(feature = "foo"))]
-    fn new(bar: u32) -> Self {
-        Self { bar }
-    }
-    fn new2(bar: u32) -> Self {
-        #[cfg(feature = "foo")]
-        { Self { foo: bar } }
-        #[cfg(not(feature = "foo"))]
-        { Self { bar } }
-    }
-    fn new2(val: u32) -> Self {
-        Self {
-            #[cfg(feature = "foo")]
-            foo: val,
-            #[cfg(not(feature = "foo"))]
-            bar: val,
-        }
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn no_such_field_with_type_macro() {
-        check_diagnostics(
-            r#"
-macro_rules! Type { () => { u32 }; }
-struct Foo { bar: Type![] }
-
-impl Foo {
-    fn new() -> Self {
-        Foo { bar: 0 }
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn missing_record_pat_field_diagnostic() {
-        check_diagnostics(
-            r#"
-struct S { foo: i32, bar: () }
-fn baz(s: S) {
-    let S { foo: _ } = s;
-      //^ Missing structure fields:
-      //| - bar
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn missing_record_pat_field_no_diagnostic_if_not_exhaustive() {
-        check_diagnostics(
-            r"
-struct S { foo: i32, bar: () }
-fn baz(s: S) -> i32 {
-    match s {
-        S { foo, .. } => foo,
-    }
-}
-",
-        )
-    }
-
-    #[test]
-    fn missing_record_pat_field_box() {
-        check_diagnostics(
-            r"
-struct S { s: Box<u32> }
-fn x(a: S) {
-    let S { box s } = a;
-}
-",
-        )
-    }
-
-    #[test]
-    fn missing_record_pat_field_ref() {
-        check_diagnostics(
-            r"
-struct S { s: u32 }
-fn x(a: S) {
-    let S { ref s } = a;
-}
-",
-        )
-    }
-
-    #[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,
-}
-        "#,
-        );
-    }
-
-    #[test]
-    fn break_outside_of_loop() {
-        check_diagnostics(
-            r#"
-fn foo() { break; }
-         //^^^^^ break outside of loop
-"#,
-        );
-    }
-
-    #[test]
-    fn missing_semicolon() {
-        check_diagnostics(
-            r#"
-                fn test() -> i32 { 123; }
-                                 //^^^ Remove this semicolon
-            "#,
-        );
-    }
-
-    // Register the required standard library types to make the tests work
-    fn add_filter_map_with_find_next_boilerplate(body: &str) -> String {
-        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 }
-            }
-        }
-        "#;
-        format!("{}{}{}", prefix, body, suffix)
-    }
-
-    #[test]
-    fn replace_filter_map_next_with_find_map2() {
-        check_diagnostics(&add_filter_map_with_find_next_boilerplate(
-            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(..)
-            }
-        "#,
-        ));
-    }
-
-    #[test]
-    fn replace_filter_map_next_with_find_map_no_diagnostic_without_next() {
-        check_diagnostics(&add_filter_map_with_find_next_boilerplate(
-            r#"
-            fn foo() {
-                let m = [1, 2, 3]
-                    .iter()
-                    .filter_map(|x| if *x == 2 { Some (4) } else { None })
-                    .len();
-            }
-            "#,
-        ));
-    }
-
-    #[test]
-    fn replace_filter_map_next_with_find_map_no_diagnostic_with_intervening_methods() {
-        check_diagnostics(&add_filter_map_with_find_next_boilerplate(
-            r#"
-            fn foo() {
-                let m = [1, 2, 3]
-                    .iter()
-                    .filter_map(|x| if *x == 2 { Some (4) } else { None })
-                    .map(|x| x + 2)
-                    .len();
-            }
-            "#,
-        ));
-    }
-
-    #[test]
-    fn replace_filter_map_next_with_find_map_no_diagnostic_if_not_in_chain() {
-        check_diagnostics(&add_filter_map_with_find_next_boilerplate(
-            r#"
-            fn foo() {
-                let m = [1, 2, 3]
-                    .iter()
-                    .filter_map(|x| if *x == 2 { Some (4) } else { None });
-                let n = m.next();
-            }
-            "#,
-        ));
-    }
-}
diff --git a/crates/hir_ty/src/diagnostics/decl_check.rs b/crates/hir_ty/src/diagnostics/decl_check.rs
index cfb5d7320..f26150b77 100644
--- a/crates/hir_ty/src/diagnostics/decl_check.rs
+++ b/crates/hir_ty/src/diagnostics/decl_check.rs
@@ -29,7 +29,6 @@ use syntax::{
 use crate::{
     db::HirDatabase,
     diagnostics::{decl_check::case_conv::*, CaseType, IdentType, IncorrectCase},
-    diagnostics_sink::DiagnosticSink,
 };
 
 mod allow {
@@ -40,10 +39,10 @@ mod allow {
     pub(super) const NON_CAMEL_CASE_TYPES: &str = "non_camel_case_types";
 }
 
-pub(super) struct DeclValidator<'a, 'b> {
+pub(super) struct DeclValidator<'a> {
     db: &'a dyn HirDatabase,
     krate: CrateId,
-    sink: &'a mut DiagnosticSink<'b>,
+    pub(super) sink: Vec<IncorrectCase>,
 }
 
 #[derive(Debug)]
@@ -53,13 +52,9 @@ struct Replacement {
     expected_case: CaseType,
 }
 
-impl<'a, 'b> DeclValidator<'a, 'b> {
-    pub(super) fn new(
-        db: &'a dyn HirDatabase,
-        krate: CrateId,
-        sink: &'a mut DiagnosticSink<'b>,
-    ) -> DeclValidator<'a, 'b> {
-        DeclValidator { db, krate, sink }
+impl<'a> DeclValidator<'a> {
+    pub(super) fn new(db: &'a dyn HirDatabase, krate: CrateId) -> DeclValidator<'a> {
+        DeclValidator { db, krate, sink: Vec::new() }
     }
 
     pub(super) fn validate_item(&mut self, item: ModuleDefId) {
@@ -131,7 +126,7 @@ impl<'a, 'b> DeclValidator<'a, 'b> {
         for (_, block_def_map) in body.blocks(self.db.upcast()) {
             for (_, module) in block_def_map.modules() {
                 for def_id in module.scope.declarations() {
-                    let mut validator = DeclValidator::new(self.db, self.krate, self.sink);
+                    let mut validator = DeclValidator::new(self.db, self.krate);
                     validator.validate_item(def_id);
                 }
             }
@@ -623,343 +618,3 @@ impl<'a, 'b> DeclValidator<'a, 'b> {
         self.sink.push(diagnostic);
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use crate::diagnostics::tests::check_diagnostics;
-
-    #[test]
-    fn incorrect_function_name() {
-        check_diagnostics(
-            r#"
-fn NonSnakeCaseName() {}
-// ^^^^^^^^^^^^^^^^ Function `NonSnakeCaseName` should have snake_case name, e.g. `non_snake_case_name`
-"#,
-        );
-    }
-
-    #[test]
-    fn incorrect_function_params() {
-        check_diagnostics(
-            r#"
-fn foo(SomeParam: u8) {}
-    // ^^^^^^^^^ 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`
-"#,
-        );
-    }
-
-    #[test]
-    fn incorrect_variable_names() {
-        check_diagnostics(
-            r#"
-fn foo() {
-    let SOME_VALUE = 10;
-     // ^^^^^^^^^^ 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`
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn incorrect_struct_names() {
-        check_diagnostics(
-            r#"
-struct non_camel_case_name {}
-    // ^^^^^^^^^^^^^^^^^^^ 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`
-"#,
-        );
-    }
-
-    #[test]
-    fn no_diagnostic_for_camel_cased_acronyms_in_struct_name() {
-        check_diagnostics(
-            r#"
-struct AABB {}
-"#,
-        );
-    }
-
-    #[test]
-    fn incorrect_struct_field() {
-        check_diagnostics(
-            r#"
-struct SomeStruct { SomeField: u8 }
-                 // ^^^^^^^^^ Field `SomeField` should have snake_case name, e.g. `some_field`
-"#,
-        );
-    }
-
-    #[test]
-    fn incorrect_enum_names() {
-        check_diagnostics(
-            r#"
-enum some_enum { Val(u8) }
-  // ^^^^^^^^^ Enum `some_enum` should have CamelCase name, e.g. `SomeEnum`
-
-enum SOME_ENUM
-  // ^^^^^^^^^ Enum `SOME_ENUM` should have CamelCase name, e.g. `SomeEnum`
-"#,
-        );
-    }
-
-    #[test]
-    fn no_diagnostic_for_camel_cased_acronyms_in_enum_name() {
-        check_diagnostics(
-            r#"
-enum AABB {}
-"#,
-        );
-    }
-
-    #[test]
-    fn incorrect_enum_variant_name() {
-        check_diagnostics(
-            r#"
-enum SomeEnum { SOME_VARIANT(u8) }
-             // ^^^^^^^^^^^^ Variant `SOME_VARIANT` should have CamelCase name, e.g. `SomeVariant`
-"#,
-        );
-    }
-
-    #[test]
-    fn incorrect_const_name() {
-        check_diagnostics(
-            r#"
-const some_weird_const: u8 = 10;
-   // ^^^^^^^^^^^^^^^^ Constant `some_weird_const` should have UPPER_SNAKE_CASE name, e.g. `SOME_WEIRD_CONST`
-
-fn func() {
-    const someConstInFunc: &str = "hi there";
-       // ^^^^^^^^^^^^^^^ Constant `someConstInFunc` should have UPPER_SNAKE_CASE name, e.g. `SOME_CONST_IN_FUNC`
-
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn incorrect_static_name() {
-        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`
-
-fn func() {
-    static someConstInFunc: &str = "hi there";
-        // ^^^^^^^^^^^^^^^ Static variable `someConstInFunc` should have UPPER_SNAKE_CASE name, e.g. `SOME_CONST_IN_FUNC`
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn fn_inside_impl_struct() {
-        check_diagnostics(
-            r#"
-struct someStruct;
-    // ^^^^^^^^^^ 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`
-        static someConstInFunc: &str = "hi there";
-            // ^^^^^^^^^^^^^^^ Static variable `someConstInFunc` should have UPPER_SNAKE_CASE name, e.g. `SOME_CONST_IN_FUNC`
-        let WHY_VAR_IS_CAPS = 10;
-         // ^^^^^^^^^^^^^^^ Variable `WHY_VAR_IS_CAPS` should have snake_case name, e.g. `why_var_is_caps`
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn no_diagnostic_for_enum_varinats() {
-        check_diagnostics(
-            r#"
-enum Option { Some, None }
-
-fn main() {
-    match Option::None {
-        None => (),
-        Some => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn non_let_bind() {
-        check_diagnostics(
-            r#"
-enum Option { Some, None }
-
-fn main() {
-    match Option::None {
-        SOME_VAR @ None => (),
-     // ^^^^^^^^ Variable `SOME_VAR` should have snake_case name, e.g. `some_var`
-        Some => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn allow_attributes() {
-        check_diagnostics(
-            r#"
-#[allow(non_snake_case)]
-fn NonSnakeCaseName(SOME_VAR: u8) -> u8{
-    // cov_flags generated output from elsewhere in this file
-    extern "C" {
-        #[no_mangle]
-        static lower_case: u8;
-    }
-
-    let OtherVar = SOME_VAR + 1;
-    OtherVar
-}
-
-#[allow(nonstandard_style)]
-mod CheckNonstandardStyle {
-    fn HiImABadFnName() {}
-}
-
-#[allow(bad_style)]
-mod CheckBadStyle {
-    fn HiImABadFnName() {}
-}
-
-mod F {
-    #![allow(non_snake_case)]
-    fn CheckItWorksWithModAttr(BAD_NAME_HI: u8) {}
-}
-
-#[allow(non_snake_case, non_camel_case_types)]
-pub struct some_type {
-    SOME_FIELD: u8,
-    SomeField: u16,
-}
-
-#[allow(non_upper_case_globals)]
-pub const some_const: u8 = 10;
-
-#[allow(non_upper_case_globals)]
-pub static SomeStatic: u8 = 10;
-    "#,
-        );
-    }
-
-    #[test]
-    fn allow_attributes_crate_attr() {
-        check_diagnostics(
-            r#"
-#![allow(non_snake_case)]
-
-mod F {
-    fn CheckItWorksWithCrateAttr(BAD_NAME_HI: u8) {}
-}
-    "#,
-        );
-    }
-
-    #[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.
-
-        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 {
-            const HiImAlsoBad: u8 = 2;
-            #[inline]
-            fn Dirty(&self) -> bool {
-                false
-            }
-        }
-
-    }
-}
-    "#,
-        );
-    }
-
-    #[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`
-}
-    "#,
-        );
-    }
-
-    #[test]
-    fn ignores_extern_items() {
-        cov_mark::check!(extern_func_incorrect_case_ignored);
-        cov_mark::check!(extern_static_incorrect_case_ignored);
-        check_diagnostics(
-            r#"
-extern {
-    fn NonSnakeCaseName(SOME_VAR: u8) -> u8;
-    pub static SomeStatic: u8 = 10;
-}
-            "#,
-        );
-    }
-
-    #[test]
-    fn infinite_loop_inner_items() {
-        check_diagnostics(
-            r#"
-fn qualify() {
-    mod foo {
-        use super::*;
-    }
-}
-            "#,
-        )
-    }
-
-    #[test] // Issue #8809.
-    fn parenthesized_parameter() {
-        check_diagnostics(r#"fn f((O): _) {}"#)
-    }
-}
diff --git a/crates/hir_ty/src/diagnostics/expr.rs b/crates/hir_ty/src/diagnostics/expr.rs
index a2a4d61db..b809b96a0 100644
--- a/crates/hir_ty/src/diagnostics/expr.rs
+++ b/crates/hir_ty/src/diagnostics/expr.rs
@@ -8,20 +8,15 @@ use hir_def::{
     expr::Statement, path::path, resolver::HasResolver, AssocItemId, DefWithBodyId, HasModule,
 };
 use hir_expand::name;
+use itertools::Either;
 use rustc_hash::FxHashSet;
-use syntax::{ast, AstPtr};
 
 use crate::{
     db::HirDatabase,
-    diagnostics::{
-        match_check::{
-            self,
-            usefulness::{compute_match_usefulness, expand_pattern, MatchCheckCtx, PatternArena},
-        },
-        MismatchedArgCount, MissingFields, MissingMatchArms, MissingOkOrSomeInTailExpr,
-        MissingPatFields, RemoveThisSemicolon,
+    diagnostics::match_check::{
+        self,
+        usefulness::{compute_match_usefulness, expand_pattern, MatchCheckCtx, PatternArena},
     },
-    diagnostics_sink::DiagnosticSink,
     AdtId, InferenceResult, Interner, TyExt, TyKind,
 };
 
@@ -31,38 +26,67 @@ pub(crate) use hir_def::{
     LocalFieldId, VariantId,
 };
 
-use super::ReplaceFilterMapNextWithFindMap;
+pub enum BodyValidationDiagnostic {
+    RecordMissingFields {
+        record: Either<ExprId, PatId>,
+        variant: VariantId,
+        missed_fields: Vec<LocalFieldId>,
+    },
+    ReplaceFilterMapNextWithFindMap {
+        method_call_expr: ExprId,
+    },
+    MismatchedArgCount {
+        call_expr: ExprId,
+        expected: usize,
+        found: usize,
+    },
+    RemoveThisSemicolon {
+        expr: ExprId,
+    },
+    MissingOkOrSomeInTailExpr {
+        expr: ExprId,
+        required: String,
+    },
+    MissingMatchArms {
+        match_expr: ExprId,
+    },
+}
+
+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());
+        validator.validate_body(db);
+        validator.diagnostics
+    }
+}
 
-pub(super) struct ExprValidator<'a, 'b: 'a> {
+struct ExprValidator {
     owner: DefWithBodyId,
     infer: Arc<InferenceResult>,
-    sink: &'a mut DiagnosticSink<'b>,
+    pub(super) diagnostics: Vec<BodyValidationDiagnostic>,
 }
 
-impl<'a, 'b> ExprValidator<'a, 'b> {
-    pub(super) fn new(
-        owner: DefWithBodyId,
-        infer: Arc<InferenceResult>,
-        sink: &'a mut DiagnosticSink<'b>,
-    ) -> ExprValidator<'a, 'b> {
-        ExprValidator { owner, infer, sink }
+impl ExprValidator {
+    fn new(owner: DefWithBodyId, infer: Arc<InferenceResult>) -> ExprValidator {
+        ExprValidator { owner, infer, diagnostics: Vec::new() }
     }
 
-    pub(super) fn validate_body(&mut self, db: &dyn HirDatabase) {
+    fn validate_body(&mut self, db: &dyn HirDatabase) {
         self.check_for_filter_map_next(db);
 
         let body = db.body(self.owner);
 
         for (id, expr) in body.exprs.iter() {
-            if let Some((variant_def, missed_fields, true)) =
+            if let Some((variant, missed_fields, true)) =
                 record_literal_missing_fields(db, &self.infer, id, expr)
             {
-                self.create_record_literal_missing_fields_diagnostic(
-                    id,
-                    db,
-                    variant_def,
+                self.diagnostics.push(BodyValidationDiagnostic::RecordMissingFields {
+                    record: Either::Left(id),
+                    variant,
                     missed_fields,
-                );
+                });
             }
 
             match expr {
@@ -76,15 +100,14 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
             }
         }
         for (id, pat) in body.pats.iter() {
-            if let Some((variant_def, missed_fields, true)) =
+            if let Some((variant, missed_fields, true)) =
                 record_pattern_missing_fields(db, &self.infer, id, pat)
             {
-                self.create_record_pattern_missing_fields_diagnostic(
-                    id,
-                    db,
-                    variant_def,
+                self.diagnostics.push(BodyValidationDiagnostic::RecordMissingFields {
+                    record: Either::Right(id),
+                    variant,
                     missed_fields,
-                );
+                });
             }
         }
         let body_expr = &body[body.body_expr];
@@ -92,71 +115,7 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
             if let Some(t) = tail {
                 self.validate_results_in_tail_expr(body.body_expr, *t, db);
             } else if let Some(Statement::Expr { expr: id, .. }) = statements.last() {
-                self.validate_missing_tail_expr(body.body_expr, *id, db);
-            }
-        }
-    }
-
-    fn create_record_literal_missing_fields_diagnostic(
-        &mut self,
-        id: ExprId,
-        db: &dyn HirDatabase,
-        variant_def: VariantId,
-        missed_fields: Vec<LocalFieldId>,
-    ) {
-        // XXX: only look at source_map if we do have missing fields
-        let (_, source_map) = db.body_with_source_map(self.owner);
-
-        if let Ok(source_ptr) = source_map.expr_syntax(id) {
-            let root = source_ptr.file_syntax(db.upcast());
-            if let ast::Expr::RecordExpr(record_expr) = &source_ptr.value.to_node(&root) {
-                if let Some(_) = record_expr.record_expr_field_list() {
-                    let variant_data = variant_def.variant_data(db.upcast());
-                    let missed_fields = missed_fields
-                        .into_iter()
-                        .map(|idx| variant_data.fields()[idx].name.clone())
-                        .collect();
-                    self.sink.push(MissingFields {
-                        file: source_ptr.file_id,
-                        field_list_parent: AstPtr::new(&record_expr),
-                        field_list_parent_path: record_expr.path().map(|path| AstPtr::new(&path)),
-                        missed_fields,
-                    })
-                }
-            }
-        }
-    }
-
-    fn create_record_pattern_missing_fields_diagnostic(
-        &mut self,
-        id: PatId,
-        db: &dyn HirDatabase,
-        variant_def: VariantId,
-        missed_fields: Vec<LocalFieldId>,
-    ) {
-        // XXX: only look at source_map if we do have missing fields
-        let (_, source_map) = db.body_with_source_map(self.owner);
-
-        if let Ok(source_ptr) = source_map.pat_syntax(id) {
-            if let Some(expr) = source_ptr.value.as_ref().left() {
-                let root = source_ptr.file_syntax(db.upcast());
-                if let ast::Pat::RecordPat(record_pat) = expr.to_node(&root) {
-                    if let Some(_) = record_pat.record_pat_field_list() {
-                        let variant_data = variant_def.variant_data(db.upcast());
-                        let missed_fields = missed_fields
-                            .into_iter()
-                            .map(|idx| variant_data.fields()[idx].name.clone())
-                            .collect();
-                        self.sink.push(MissingPatFields {
-                            file: source_ptr.file_id,
-                            field_list_parent: AstPtr::new(&record_pat),
-                            field_list_parent_path: record_pat
-                                .path()
-                                .map(|path| AstPtr::new(&path)),
-                            missed_fields,
-                        })
-                    }
-                }
+                self.validate_missing_tail_expr(body.body_expr, *id);
             }
         }
     }
@@ -199,13 +158,11 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
                 if function_id == *next_function_id {
                     if let Some(filter_map_id) = prev {
                         if *receiver == filter_map_id {
-                            let (_, source_map) = db.body_with_source_map(self.owner);
-                            if let Ok(next_source_ptr) = source_map.expr_syntax(id) {
-                                self.sink.push(ReplaceFilterMapNextWithFindMap {
-                                    file: next_source_ptr.file_id,
-                                    next_expr: next_source_ptr.value,
-                                });
-                            }
+                            self.diagnostics.push(
+                                BodyValidationDiagnostic::ReplaceFilterMapNextWithFindMap {
+                                    method_call_expr: id,
+                                },
+                            );
                         }
                     }
                 }
@@ -266,19 +223,15 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
         let mut arg_count = args.len();
 
         if arg_count != param_count {
-            let (_, source_map) = db.body_with_source_map(self.owner);
-            if let Ok(source_ptr) = source_map.expr_syntax(call_id) {
-                if is_method_call {
-                    param_count -= 1;
-                    arg_count -= 1;
-                }
-                self.sink.push(MismatchedArgCount {
-                    file: source_ptr.file_id,
-                    call_expr: source_ptr.value,
-                    expected: param_count,
-                    found: arg_count,
-                });
+            if is_method_call {
+                param_count -= 1;
+                arg_count -= 1;
             }
+            self.diagnostics.push(BodyValidationDiagnostic::MismatchedArgCount {
+                call_expr: call_id,
+                expected: param_count,
+                found: arg_count,
+            });
         }
     }
 
@@ -346,8 +299,7 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
             // fit the match expression, we skip this diagnostic. Skipping the entire
             // diagnostic rather than just not including this match arm is preferred
             // to avoid the chance of false positives.
-            #[cfg(test)]
-            match_check::tests::report_bail_out(db, self.owner, arm.pat, self.sink);
+            cov_mark::hit!(validate_match_bailed_out);
             return;
         }
 
@@ -382,20 +334,7 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
         // FIXME Report witnesses
         // eprintln!("compute_match_usefulness(..) -> {:?}", &witnesses);
         if !witnesses.is_empty() {
-            if let Ok(source_ptr) = source_map.expr_syntax(id) {
-                let root = source_ptr.file_syntax(db.upcast());
-                if let ast::Expr::MatchExpr(match_expr) = &source_ptr.value.to_node(&root) {
-                    if let (Some(match_expr), Some(arms)) =
-                        (match_expr.expr(), match_expr.match_arm_list())
-                    {
-                        self.sink.push(MissingMatchArms {
-                            file: source_ptr.file_id,
-                            match_expr: AstPtr::new(&match_expr),
-                            arms: AstPtr::new(&arms),
-                        })
-                    }
-                }
-            }
+            self.diagnostics.push(BodyValidationDiagnostic::MissingMatchArms { match_expr: id });
         }
     }
 
@@ -453,24 +392,12 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
         if params.len(&Interner) > 0
             && params.at(&Interner, 0).ty(&Interner) == Some(&mismatch.actual)
         {
-            let (_, source_map) = db.body_with_source_map(self.owner);
-
-            if let Ok(source_ptr) = source_map.expr_syntax(id) {
-                self.sink.push(MissingOkOrSomeInTailExpr {
-                    file: source_ptr.file_id,
-                    expr: source_ptr.value,
-                    required,
-                });
-            }
+            self.diagnostics
+                .push(BodyValidationDiagnostic::MissingOkOrSomeInTailExpr { expr: id, required });
         }
     }
 
-    fn validate_missing_tail_expr(
-        &mut self,
-        body_id: ExprId,
-        possible_tail_id: ExprId,
-        db: &dyn HirDatabase,
-    ) {
+    fn validate_missing_tail_expr(&mut self, body_id: ExprId, possible_tail_id: ExprId) {
         let mismatch = match self.infer.type_mismatch_for_expr(body_id) {
             Some(m) => m,
             None => return,
@@ -485,12 +412,8 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
             return;
         }
 
-        let (_, source_map) = db.body_with_source_map(self.owner);
-
-        if let Ok(source_ptr) = source_map.expr_syntax(possible_tail_id) {
-            self.sink
-                .push(RemoveThisSemicolon { file: source_ptr.file_id, expr: source_ptr.value });
-        }
+        self.diagnostics
+            .push(BodyValidationDiagnostic::RemoveThisSemicolon { expr: possible_tail_id });
     }
 }
 
@@ -568,258 +491,3 @@ fn types_of_subpatterns_do_match(pat: PatId, body: &Body, infer: &InferenceResul
     walk(pat, body, infer, &mut has_type_mismatches);
     !has_type_mismatches
 }
-
-#[cfg(test)]
-mod tests {
-    use crate::diagnostics::tests::check_diagnostics;
-
-    #[test]
-    fn simple_free_fn_zero() {
-        check_diagnostics(
-            r#"
-fn zero() {}
-fn f() { zero(1); }
-       //^^^^^^^ Expected 0 arguments, found 1
-"#,
-        );
-
-        check_diagnostics(
-            r#"
-fn zero() {}
-fn f() { zero(); }
-"#,
-        );
-    }
-
-    #[test]
-    fn simple_free_fn_one() {
-        check_diagnostics(
-            r#"
-fn one(arg: u8) {}
-fn f() { one(); }
-       //^^^^^ Expected 1 argument, found 0
-"#,
-        );
-
-        check_diagnostics(
-            r#"
-fn one(arg: u8) {}
-fn f() { one(1); }
-"#,
-        );
-    }
-
-    #[test]
-    fn method_as_fn() {
-        check_diagnostics(
-            r#"
-struct S;
-impl S { fn method(&self) {} }
-
-fn f() {
-    S::method();
-} //^^^^^^^^^^^ Expected 1 argument, found 0
-"#,
-        );
-
-        check_diagnostics(
-            r#"
-struct S;
-impl S { fn method(&self) {} }
-
-fn f() {
-    S::method(&S);
-    S.method();
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn method_with_arg() {
-        check_diagnostics(
-            r#"
-struct S;
-impl S { fn method(&self, arg: u8) {} }
-
-            fn f() {
-                S.method();
-            } //^^^^^^^^^^ Expected 1 argument, found 0
-            "#,
-        );
-
-        check_diagnostics(
-            r#"
-struct S;
-impl S { fn method(&self, arg: u8) {} }
-
-fn f() {
-    S::method(&S, 0);
-    S.method(1);
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn method_unknown_receiver() {
-        // note: this is incorrect code, so there might be errors on this in the
-        // future, but we shouldn't emit an argument count diagnostic here
-        check_diagnostics(
-            r#"
-trait Foo { fn method(&self, arg: usize) {} }
-
-fn f() {
-    let x;
-    x.method();
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn tuple_struct() {
-        check_diagnostics(
-            r#"
-struct Tup(u8, u16);
-fn f() {
-    Tup(0);
-} //^^^^^^ Expected 2 arguments, found 1
-"#,
-        )
-    }
-
-    #[test]
-    fn enum_variant() {
-        check_diagnostics(
-            r#"
-enum En { Variant(u8, u16), }
-fn f() {
-    En::Variant(0);
-} //^^^^^^^^^^^^^^ Expected 2 arguments, found 1
-"#,
-        )
-    }
-
-    #[test]
-    fn enum_variant_type_macro() {
-        check_diagnostics(
-            r#"
-macro_rules! Type {
-    () => { u32 };
-}
-enum Foo {
-    Bar(Type![])
-}
-impl Foo {
-    fn new() {
-        Foo::Bar(0);
-        Foo::Bar(0, 1);
-      //^^^^^^^^^^^^^^ Expected 1 argument, found 2
-        Foo::Bar();
-      //^^^^^^^^^^ Expected 1 argument, found 0
-    }
-}
-        "#,
-        );
-    }
-
-    #[test]
-    fn varargs() {
-        check_diagnostics(
-            r#"
-extern "C" {
-    fn fixed(fixed: u8);
-    fn varargs(fixed: u8, ...);
-    fn varargs2(...);
-}
-
-fn f() {
-    unsafe {
-        fixed(0);
-        fixed(0, 1);
-      //^^^^^^^^^^^ Expected 1 argument, found 2
-        varargs(0);
-        varargs(0, 1);
-        varargs2();
-        varargs2(0);
-        varargs2(0, 1);
-    }
-}
-        "#,
-        )
-    }
-
-    #[test]
-    fn arg_count_lambda() {
-        check_diagnostics(
-            r#"
-fn main() {
-    let f = |()| ();
-    f();
-  //^^^ Expected 1 argument, found 0
-    f(());
-    f((), ());
-  //^^^^^^^^^ Expected 1 argument, found 2
-}
-"#,
-        )
-    }
-
-    #[test]
-    fn cfgd_out_call_arguments() {
-        check_diagnostics(
-            r#"
-struct C(#[cfg(FALSE)] ());
-impl C {
-    fn new() -> Self {
-        Self(
-            #[cfg(FALSE)]
-            (),
-        )
-    }
-
-    fn method(&self) {}
-}
-
-fn main() {
-    C::new().method(#[cfg(FALSE)] 0);
-}
-            "#,
-        );
-    }
-
-    #[test]
-    fn cfgd_out_fn_params() {
-        check_diagnostics(
-            r#"
-fn foo(#[cfg(NEVER)] x: ()) {}
-
-struct S;
-
-impl S {
-    fn method(#[cfg(NEVER)] self) {}
-    fn method2(#[cfg(NEVER)] self, arg: u8) {}
-    fn method3(self, #[cfg(NEVER)] arg: u8) {}
-}
-
-extern "C" {
-    fn fixed(fixed: u8, #[cfg(NEVER)] ...);
-    fn varargs(#[cfg(not(NEVER))] ...);
-}
-
-fn main() {
-    foo();
-    S::method();
-    S::method2(0);
-    S::method3(S);
-    S.method3();
-    unsafe {
-        fixed(0);
-        varargs(1, 2, 3);
-    }
-}
-            "#,
-        )
-    }
-}
diff --git a/crates/hir_ty/src/diagnostics/match_check.rs b/crates/hir_ty/src/diagnostics/match_check.rs
index c8e1b23de..a30e42699 100644
--- a/crates/hir_ty/src/diagnostics/match_check.rs
+++ b/crates/hir_ty/src/diagnostics/match_check.rs
@@ -364,960 +364,3 @@ impl PatternFoldable for PatKind {
         }
     }
 }
-
-#[cfg(test)]
-pub(super) mod tests {
-    mod report {
-        use std::any::Any;
-
-        use hir_def::{expr::PatId, DefWithBodyId};
-        use hir_expand::{HirFileId, InFile};
-        use syntax::SyntaxNodePtr;
-
-        use crate::{
-            db::HirDatabase,
-            diagnostics_sink::{Diagnostic, DiagnosticCode, DiagnosticSink},
-        };
-
-        /// In tests, match check bails out loudly.
-        /// This helps to catch incorrect tests that pass due to false negatives.
-        pub(crate) fn report_bail_out(
-            db: &dyn HirDatabase,
-            def: DefWithBodyId,
-            pat: PatId,
-            sink: &mut DiagnosticSink,
-        ) {
-            let (_, source_map) = db.body_with_source_map(def);
-            if let Ok(source_ptr) = source_map.pat_syntax(pat) {
-                let pat_syntax_ptr = source_ptr.value.either(Into::into, Into::into);
-                sink.push(BailedOut { file: source_ptr.file_id, pat_syntax_ptr });
-            }
-        }
-
-        #[derive(Debug)]
-        struct BailedOut {
-            file: HirFileId,
-            pat_syntax_ptr: SyntaxNodePtr,
-        }
-
-        impl Diagnostic for BailedOut {
-            fn code(&self) -> DiagnosticCode {
-                DiagnosticCode("internal:match-check-bailed-out")
-            }
-            fn message(&self) -> String {
-                format!("Internal: match check bailed out")
-            }
-            fn display_source(&self) -> InFile<SyntaxNodePtr> {
-                InFile { file_id: self.file, value: self.pat_syntax_ptr.clone() }
-            }
-            fn as_any(&self) -> &(dyn Any + Send + 'static) {
-                self
-            }
-        }
-    }
-
-    use crate::diagnostics::tests::check_diagnostics;
-
-    pub(crate) use self::report::report_bail_out;
-
-    #[test]
-    fn empty_tuple() {
-        check_diagnostics(
-            r#"
-fn main() {
-    match () { }
-        //^^ Missing match arm
-    match (()) { }
-        //^^^^ Missing match arm
-
-    match () { _ => (), }
-    match () { () => (), }
-    match (()) { (()) => (), }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn tuple_of_two_empty_tuple() {
-        check_diagnostics(
-            r#"
-fn main() {
-    match ((), ()) { }
-        //^^^^^^^^ Missing match arm
-
-    match ((), ()) { ((), ()) => (), }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn boolean() {
-        check_diagnostics(
-            r#"
-fn test_main() {
-    match false { }
-        //^^^^^ Missing match arm
-    match false { true => (), }
-        //^^^^^ Missing match arm
-    match (false, true) {}
-        //^^^^^^^^^^^^^ Missing match arm
-    match (false, true) { (true, true) => (), }
-        //^^^^^^^^^^^^^ Missing match arm
-    match (false, true) {
-        //^^^^^^^^^^^^^ Missing match arm
-        (false, true) => (),
-        (false, false) => (),
-        (true, false) => (),
-    }
-    match (false, true) { (true, _x) => (), }
-        //^^^^^^^^^^^^^ Missing match arm
-
-    match false { true => (), false => (), }
-    match (false, true) {
-        (false, _) => (),
-        (true, false) => (),
-        (_, true) => (),
-    }
-    match (false, true) {
-        (true, true) => (),
-        (true, false) => (),
-        (false, true) => (),
-        (false, false) => (),
-    }
-    match (false, true) {
-        (true, _x) => (),
-        (false, true) => (),
-        (false, false) => (),
-    }
-    match (false, true, false) {
-        (false, ..) => (),
-        (true, ..) => (),
-    }
-    match (false, true, false) {
-        (.., false) => (),
-        (.., true) => (),
-    }
-    match (false, true, false) { (..) => (), }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn tuple_of_tuple_and_bools() {
-        check_diagnostics(
-            r#"
-fn main() {
-    match (false, ((), false)) {}
-        //^^^^^^^^^^^^^^^^^^^^ Missing match arm
-    match (false, ((), false)) { (true, ((), true)) => (), }
-        //^^^^^^^^^^^^^^^^^^^^ Missing match arm
-    match (false, ((), false)) { (true, _) => (), }
-        //^^^^^^^^^^^^^^^^^^^^ Missing match arm
-
-    match (false, ((), false)) {
-        (true, ((), true)) => (),
-        (true, ((), false)) => (),
-        (false, ((), true)) => (),
-        (false, ((), false)) => (),
-    }
-    match (false, ((), false)) {
-        (true, ((), true)) => (),
-        (true, ((), false)) => (),
-        (false, _) => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn enums() {
-        check_diagnostics(
-            r#"
-enum Either { A, B, }
-
-fn main() {
-    match Either::A { }
-        //^^^^^^^^^ Missing match arm
-    match Either::B { Either::A => (), }
-        //^^^^^^^^^ Missing match arm
-
-    match &Either::B {
-        //^^^^^^^^^^ Missing match arm
-        Either::A => (),
-    }
-
-    match Either::B {
-        Either::A => (), Either::B => (),
-    }
-    match &Either::B {
-        Either::A => (), Either::B => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn enum_containing_bool() {
-        check_diagnostics(
-            r#"
-enum Either { A(bool), B }
-
-fn main() {
-    match Either::B { }
-        //^^^^^^^^^ Missing match arm
-    match Either::B {
-        //^^^^^^^^^ Missing match arm
-        Either::A(true) => (), Either::B => ()
-    }
-
-    match Either::B {
-        Either::A(true) => (),
-        Either::A(false) => (),
-        Either::B => (),
-    }
-    match Either::B {
-        Either::B => (),
-        _ => (),
-    }
-    match Either::B {
-        Either::A(_) => (),
-        Either::B => (),
-    }
-
-}
-        "#,
-        );
-    }
-
-    #[test]
-    fn enum_different_sizes() {
-        check_diagnostics(
-            r#"
-enum Either { A(bool), B(bool, bool) }
-
-fn main() {
-    match Either::A(false) {
-        //^^^^^^^^^^^^^^^^ Missing match arm
-        Either::A(_) => (),
-        Either::B(false, _) => (),
-    }
-
-    match Either::A(false) {
-        Either::A(_) => (),
-        Either::B(true, _) => (),
-        Either::B(false, _) => (),
-    }
-    match Either::A(false) {
-        Either::A(true) | Either::A(false) => (),
-        Either::B(true, _) => (),
-        Either::B(false, _) => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn tuple_of_enum_no_diagnostic() {
-        check_diagnostics(
-            r#"
-enum Either { A(bool), B(bool, bool) }
-enum Either2 { C, D }
-
-fn main() {
-    match (Either::A(false), Either2::C) {
-        (Either::A(true), _) | (Either::A(false), _) => (),
-        (Either::B(true, _), Either2::C) => (),
-        (Either::B(false, _), Either2::C) => (),
-        (Either::B(_, _), Either2::D) => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn or_pattern_no_diagnostic() {
-        check_diagnostics(
-            r#"
-enum Either {A, B}
-
-fn main() {
-    match (Either::A, Either::B) {
-        (Either::A | Either::B, _) => (),
-    }
-}"#,
-        )
-    }
-
-    #[test]
-    fn mismatched_types() {
-        // Match statements with arms that don't match the
-        // expression pattern do not fire this diagnostic.
-        check_diagnostics(
-            r#"
-enum Either { A, B }
-enum Either2 { C, D }
-
-fn main() {
-    match Either::A {
-        Either2::C => (),
-    //  ^^^^^^^^^^ Internal: match check bailed out
-        Either2::D => (),
-    }
-    match (true, false) {
-        (true, false, true) => (),
-    //  ^^^^^^^^^^^^^^^^^^^ Internal: match check bailed out
-        (true) => (),
-    }
-    match (true, false) { (true,) => {} }
-    //                    ^^^^^^^ Internal: match check bailed out
-    match (0) { () => () }
-            //  ^^ Internal: match check bailed out
-    match Unresolved::Bar { Unresolved::Baz => () }
-}
-        "#,
-        );
-    }
-
-    #[test]
-    fn mismatched_types_in_or_patterns() {
-        check_diagnostics(
-            r#"
-fn main() {
-    match false { true | () => {} }
-    //            ^^^^^^^^^ Internal: match check bailed out
-    match (false,) { (true | (),) => {} }
-    //               ^^^^^^^^^^^^ Internal: match check bailed out
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn malformed_match_arm_tuple_enum_missing_pattern() {
-        // We are testing to be sure we don't panic here when the match
-        // arm `Either::B` is missing its pattern.
-        check_diagnostics(
-            r#"
-enum Either { A, B(u32) }
-
-fn main() {
-    match Either::A {
-        Either::A => (),
-        Either::B() => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn malformed_match_arm_extra_fields() {
-        check_diagnostics(
-            r#"
-enum A { B(isize, isize), C }
-fn main() {
-    match A::B(1, 2) {
-        A::B(_, _, _) => (),
-    //  ^^^^^^^^^^^^^ Internal: match check bailed out
-    }
-    match A::B(1, 2) {
-        A::C(_) => (),
-    //  ^^^^^^^ Internal: match check bailed out
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn expr_diverges() {
-        check_diagnostics(
-            r#"
-enum Either { A, B }
-
-fn main() {
-    match loop {} {
-        Either::A => (),
-    //  ^^^^^^^^^ Internal: match check bailed out
-        Either::B => (),
-    }
-    match loop {} {
-        Either::A => (),
-    //  ^^^^^^^^^ Internal: match check bailed out
-    }
-    match loop { break Foo::A } {
-        //^^^^^^^^^^^^^^^^^^^^^ Missing match arm
-        Either::A => (),
-    }
-    match loop { break Foo::A } {
-        Either::A => (),
-        Either::B => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn expr_partially_diverges() {
-        check_diagnostics(
-            r#"
-enum Either<T> { A(T), B }
-
-fn foo() -> Either<!> { Either::B }
-fn main() -> u32 {
-    match foo() {
-        Either::A(val) => val,
-        Either::B => 0,
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn enum_record() {
-        check_diagnostics(
-            r#"
-enum Either { A { foo: bool }, B }
-
-fn main() {
-    let a = Either::A { foo: true };
-    match a { }
-        //^ Missing match arm
-    match a { Either::A { foo: true } => () }
-        //^ Missing match arm
-    match a {
-        Either::A { } => (),
-      //^^^^^^^^^ Missing structure fields:
-      //        | - foo
-        Either::B => (),
-    }
-    match a {
-        //^ Missing match arm
-        Either::A { } => (),
-    } //^^^^^^^^^ Missing structure fields:
-      //        | - foo
-
-    match a {
-        Either::A { foo: true } => (),
-        Either::A { foo: false } => (),
-        Either::B => (),
-    }
-    match a {
-        Either::A { foo: _ } => (),
-        Either::B => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn enum_record_fields_out_of_order() {
-        check_diagnostics(
-            r#"
-enum Either {
-    A { foo: bool, bar: () },
-    B,
-}
-
-fn main() {
-    let a = Either::A { foo: true, bar: () };
-    match a {
-        //^ Missing match arm
-        Either::A { bar: (), foo: false } => (),
-        Either::A { foo: true, bar: () } => (),
-    }
-
-    match a {
-        Either::A { bar: (), foo: false } => (),
-        Either::A { foo: true, bar: () } => (),
-        Either::B => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn enum_record_ellipsis() {
-        check_diagnostics(
-            r#"
-enum Either {
-    A { foo: bool, bar: bool },
-    B,
-}
-
-fn main() {
-    let a = Either::B;
-    match a {
-        //^ Missing match arm
-        Either::A { foo: true, .. } => (),
-        Either::B => (),
-    }
-    match a {
-        //^ Missing match arm
-        Either::A { .. } => (),
-    }
-
-    match a {
-        Either::A { foo: true, .. } => (),
-        Either::A { foo: false, .. } => (),
-        Either::B => (),
-    }
-
-    match a {
-        Either::A { .. } => (),
-        Either::B => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn enum_tuple_partial_ellipsis() {
-        check_diagnostics(
-            r#"
-enum Either {
-    A(bool, bool, bool, bool),
-    B,
-}
-
-fn main() {
-    match Either::B {
-        //^^^^^^^^^ Missing match arm
-        Either::A(true, .., true) => (),
-        Either::A(true, .., false) => (),
-        Either::A(false, .., false) => (),
-        Either::B => (),
-    }
-    match Either::B {
-        //^^^^^^^^^ Missing match arm
-        Either::A(true, .., true) => (),
-        Either::A(true, .., false) => (),
-        Either::A(.., true) => (),
-        Either::B => (),
-    }
-
-    match Either::B {
-        Either::A(true, .., true) => (),
-        Either::A(true, .., false) => (),
-        Either::A(false, .., true) => (),
-        Either::A(false, .., false) => (),
-        Either::B => (),
-    }
-    match Either::B {
-        Either::A(true, .., true) => (),
-        Either::A(true, .., false) => (),
-        Either::A(.., true) => (),
-        Either::A(.., false) => (),
-        Either::B => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn never() {
-        check_diagnostics(
-            r#"
-enum Never {}
-
-fn enum_(never: Never) {
-    match never {}
-}
-fn enum_ref(never: &Never) {
-    match never {}
-        //^^^^^ Missing match arm
-}
-fn bang(never: !) {
-    match never {}
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn unknown_type() {
-        check_diagnostics(
-            r#"
-enum Option<T> { Some(T), None }
-
-fn main() {
-    // `Never` is deliberately not defined so that it's an uninferred type.
-    match Option::<Never>::None {
-        None => (),
-        Some(never) => match never {},
-    //  ^^^^^^^^^^^ Internal: match check bailed out
-    }
-    match Option::<Never>::None {
-        //^^^^^^^^^^^^^^^^^^^^^ Missing match arm
-        Option::Some(_never) => {},
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn tuple_of_bools_with_ellipsis_at_end_missing_arm() {
-        check_diagnostics(
-            r#"
-fn main() {
-    match (false, true, false) {
-        //^^^^^^^^^^^^^^^^^^^^ Missing match arm
-        (false, ..) => (),
-    }
-}"#,
-        );
-    }
-
-    #[test]
-    fn tuple_of_bools_with_ellipsis_at_beginning_missing_arm() {
-        check_diagnostics(
-            r#"
-fn main() {
-    match (false, true, false) {
-        //^^^^^^^^^^^^^^^^^^^^ Missing match arm
-        (.., false) => (),
-    }
-}"#,
-        );
-    }
-
-    #[test]
-    fn tuple_of_bools_with_ellipsis_in_middle_missing_arm() {
-        check_diagnostics(
-            r#"
-fn main() {
-    match (false, true, false) {
-        //^^^^^^^^^^^^^^^^^^^^ Missing match arm
-        (true, .., false) => (),
-    }
-}"#,
-        );
-    }
-
-    #[test]
-    fn record_struct() {
-        check_diagnostics(
-            r#"struct Foo { a: bool }
-fn main(f: Foo) {
-    match f {}
-        //^ Missing match arm
-    match f { Foo { a: true } => () }
-        //^ Missing match arm
-    match &f { Foo { a: true } => () }
-        //^^ Missing match arm
-    match f { Foo { a: _ } => () }
-    match f {
-        Foo { a: true } => (),
-        Foo { a: false } => (),
-    }
-    match &f {
-        Foo { a: true } => (),
-        Foo { a: false } => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn tuple_struct() {
-        check_diagnostics(
-            r#"struct Foo(bool);
-fn main(f: Foo) {
-    match f {}
-        //^ Missing match arm
-    match f { Foo(true) => () }
-        //^ Missing match arm
-    match f {
-        Foo(true) => (),
-        Foo(false) => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn unit_struct() {
-        check_diagnostics(
-            r#"struct Foo;
-fn main(f: Foo) {
-    match f {}
-        //^ Missing match arm
-    match f { Foo => () }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn record_struct_ellipsis() {
-        check_diagnostics(
-            r#"struct Foo { foo: bool, bar: bool }
-fn main(f: Foo) {
-    match f { Foo { foo: true, .. } => () }
-        //^ Missing match arm
-    match f {
-        //^ Missing match arm
-        Foo { foo: true, .. } => (),
-        Foo { bar: false, .. } => ()
-    }
-    match f { Foo { .. } => () }
-    match f {
-        Foo { foo: true, .. } => (),
-        Foo { foo: false, .. } => ()
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn internal_or() {
-        check_diagnostics(
-            r#"
-fn main() {
-    enum Either { A(bool), B }
-    match Either::B {
-        //^^^^^^^^^ Missing match arm
-        Either::A(true | false) => (),
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn no_panic_at_unimplemented_subpattern_type() {
-        check_diagnostics(
-            r#"
-struct S { a: char}
-fn main(v: S) {
-    match v { S{ a }      => {} }
-    match v { S{ a: _x }  => {} }
-    match v { S{ a: 'a' } => {} }
-            //^^^^^^^^^^^ Internal: match check bailed out
-    match v { S{..}       => {} }
-    match v { _           => {} }
-    match v { }
-        //^ Missing match arm
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn binding() {
-        check_diagnostics(
-            r#"
-fn main() {
-    match true {
-        _x @ true => {}
-        false     => {}
-    }
-    match true { _x @ true => {} }
-        //^^^^ Missing match arm
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn binding_ref_has_correct_type() {
-        // Asserts `PatKind::Binding(ref _x): bool`, not &bool.
-        // If that's not true match checking will panic with "incompatible constructors"
-        // FIXME: make facilities to test this directly like `tests::check_infer(..)`
-        check_diagnostics(
-            r#"
-enum Foo { A }
-fn main() {
-    // FIXME: this should not bail out but current behavior is such as the old algorithm.
-    // ExprValidator::validate_match(..) checks types of top level patterns incorrecly.
-    match Foo::A {
-        ref _x => {}
-    //  ^^^^^^ Internal: match check bailed out
-        Foo::A => {}
-    }
-    match (true,) {
-        (ref _x,) => {}
-        (true,) => {}
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn enum_non_exhaustive() {
-        check_diagnostics(
-            r#"
-//- /lib.rs crate:lib
-#[non_exhaustive]
-pub enum E { A, B }
-fn _local() {
-    match E::A { _ => {} }
-    match E::A {
-        E::A => {}
-        E::B => {}
-    }
-    match E::A {
-        E::A | E::B => {}
-    }
-}
-
-//- /main.rs crate:main deps:lib
-use lib::E;
-fn main() {
-    match E::A { _ => {} }
-    match E::A {
-        //^^^^ Missing match arm
-        E::A => {}
-        E::B => {}
-    }
-    match E::A {
-        //^^^^ Missing match arm
-        E::A | E::B => {}
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn match_guard() {
-        check_diagnostics(
-            r#"
-fn main() {
-    match true {
-        true if false => {}
-        true          => {}
-        false         => {}
-    }
-    match true {
-        //^^^^ Missing match arm
-        true if false => {}
-        false         => {}
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn pattern_type_is_of_substitution() {
-        cov_mark::check!(match_check_wildcard_expanded_to_substitutions);
-        check_diagnostics(
-            r#"
-struct Foo<T>(T);
-struct Bar;
-fn main() {
-    match Foo(Bar) {
-        _ | Foo(Bar) => {}
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn record_struct_no_such_field() {
-        check_diagnostics(
-            r#"
-struct Foo { }
-fn main(f: Foo) {
-    match f { Foo { bar } => () }
-    //        ^^^^^^^^^^^ Internal: match check bailed out
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn match_ergonomics_issue_9095() {
-        check_diagnostics(
-            r#"
-enum Foo<T> { A(T) }
-fn main() {
-    match &Foo::A(true) {
-        _ => {}
-        Foo::A(_) => {}
-    }
-}
-"#,
-        );
-    }
-
-    mod false_negatives {
-        //! The implementation of match checking here is a work in progress. As we roll this out, we
-        //! prefer false negatives to false positives (ideally there would be no false positives). This
-        //! test module should document known false negatives. Eventually we will have a complete
-        //! implementation of match checking and this module will be empty.
-        //!
-        //! The reasons for documenting known false negatives:
-        //!
-        //!   1. It acts as a backlog of work that can be done to improve the behavior of the system.
-        //!   2. It ensures the code doesn't panic when handling these cases.
-        use super::*;
-
-        #[test]
-        fn integers() {
-            // We don't currently check integer exhaustiveness.
-            check_diagnostics(
-                r#"
-fn main() {
-    match 5 {
-        10 => (),
-    //  ^^ Internal: match check bailed out
-        11..20 => (),
-    }
-}
-"#,
-            );
-        }
-
-        #[test]
-        fn reference_patterns_at_top_level() {
-            check_diagnostics(
-                r#"
-fn main() {
-    match &false {
-        &true => {}
-    //  ^^^^^ Internal: match check bailed out
-    }
-}
-            "#,
-            );
-        }
-
-        #[test]
-        fn reference_patterns_in_fields() {
-            check_diagnostics(
-                r#"
-fn main() {
-    match (&false,) {
-        (true,) => {}
-    //  ^^^^^^^ Internal: match check bailed out
-    }
-    match (&false,) {
-        (&true,) => {}
-    //  ^^^^^^^^ Internal: match check bailed out
-    }
-}
-            "#,
-            );
-        }
-    }
-}
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 1f4219b42..471cd4921 100644
--- a/crates/hir_ty/src/diagnostics/match_check/deconstruct_pat.rs
+++ b/crates/hir_ty/src/diagnostics/match_check/deconstruct_pat.rs
@@ -528,7 +528,7 @@ impl SplitWildcard {
                 smallvec![NonExhaustive]
             }
             TyKind::Never => SmallVec::new(),
-            _ if cx.is_uninhabited(&pcx.ty) => SmallVec::new(),
+            _ if cx.is_uninhabited(pcx.ty) => SmallVec::new(),
             TyKind::Adt(..) | TyKind::Tuple(..) | TyKind::Ref(..) => smallvec![Single],
             // This type is one for which we cannot list constructors, like `str` or `f64`.
             _ => smallvec![NonExhaustive],
diff --git a/crates/hir_ty/src/diagnostics/match_check/usefulness.rs b/crates/hir_ty/src/diagnostics/match_check/usefulness.rs
index bd76a606c..8451f9df5 100644
--- a/crates/hir_ty/src/diagnostics/match_check/usefulness.rs
+++ b/crates/hir_ty/src/diagnostics/match_check/usefulness.rs
@@ -1,5 +1,5 @@
 //! Based on rust-lang/rust 1.52.0-nightly (25c15cdbe 2021-04-22)
-//! https://github.com/rust-lang/rust/blob/25c15cdbe/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
+//! <https://github.com/rust-lang/rust/blob/25c15cdbe/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs>
 //!
 //! -----
 //!
@@ -645,7 +645,7 @@ impl SubPatSet {
             (Seq { subpats: s_set }, Seq { subpats: mut o_set }) => {
                 s_set.retain(|i, s_sub_set| {
                     // Missing entries count as full.
-                    let o_sub_set = o_set.remove(&i).unwrap_or(Full);
+                    let o_sub_set = o_set.remove(i).unwrap_or(Full);
                     s_sub_set.union(o_sub_set);
                     // We drop full entries.
                     !s_sub_set.is_full()
@@ -656,7 +656,7 @@ impl SubPatSet {
             (Alt { subpats: s_set, .. }, Alt { subpats: mut o_set, .. }) => {
                 s_set.retain(|i, s_sub_set| {
                     // Missing entries count as empty.
-                    let o_sub_set = o_set.remove(&i).unwrap_or(Empty);
+                    let o_sub_set = o_set.remove(i).unwrap_or(Empty);
                     s_sub_set.union(o_sub_set);
                     // We drop empty entries.
                     !s_sub_set.is_empty()
@@ -898,7 +898,7 @@ impl Usefulness {
                 } else {
                     witnesses
                         .into_iter()
-                        .map(|witness| witness.apply_constructor(pcx, &ctor, ctor_wild_subpatterns))
+                        .map(|witness| witness.apply_constructor(pcx, ctor, ctor_wild_subpatterns))
                         .collect()
                 };
                 WithWitnesses(new_witnesses)
diff --git a/crates/hir_ty/src/diagnostics/unsafe_check.rs b/crates/hir_ty/src/diagnostics/unsafe_check.rs
index c3c483425..777f347b8 100644
--- a/crates/hir_ty/src/diagnostics/unsafe_check.rs
+++ b/crates/hir_ty/src/diagnostics/unsafe_check.rs
@@ -1,8 +1,6 @@
 //! Provides validations for unsafe code. Currently checks if unsafe functions are missing
 //! unsafe blocks.
 
-use std::sync::Arc;
-
 use hir_def::{
     body::Body,
     expr::{Expr, ExprId, UnaryOp},
@@ -10,60 +8,32 @@ use hir_def::{
     DefWithBodyId,
 };
 
-use crate::{
-    db::HirDatabase, diagnostics::MissingUnsafe, diagnostics_sink::DiagnosticSink, InferenceResult,
-    Interner, TyExt, TyKind,
-};
+use crate::{db::HirDatabase, InferenceResult, Interner, TyExt, TyKind};
 
-pub(super) struct UnsafeValidator<'a, 'b: 'a> {
-    owner: DefWithBodyId,
-    infer: Arc<InferenceResult>,
-    sink: &'a mut DiagnosticSink<'b>,
-}
+pub fn missing_unsafe(db: &dyn HirDatabase, def: DefWithBodyId) -> Vec<ExprId> {
+    let infer = db.infer(def);
 
-impl<'a, 'b> UnsafeValidator<'a, 'b> {
-    pub(super) fn new(
-        owner: DefWithBodyId,
-        infer: Arc<InferenceResult>,
-        sink: &'a mut DiagnosticSink<'b>,
-    ) -> UnsafeValidator<'a, 'b> {
-        UnsafeValidator { owner, infer, sink }
+    let is_unsafe = match def {
+        DefWithBodyId::FunctionId(it) => db.function_data(it).is_unsafe(),
+        DefWithBodyId::StaticId(_) | DefWithBodyId::ConstId(_) => false,
+    };
+    if is_unsafe {
+        return Vec::new();
     }
 
-    pub(super) fn validate_body(&mut self, db: &dyn HirDatabase) {
-        let def = self.owner;
-        let unsafe_expressions = unsafe_expressions(db, self.infer.as_ref(), def);
-        let is_unsafe = match self.owner {
-            DefWithBodyId::FunctionId(it) => db.function_data(it).is_unsafe(),
-            DefWithBodyId::StaticId(_) | DefWithBodyId::ConstId(_) => false,
-        };
-        if is_unsafe
-            || unsafe_expressions
-                .iter()
-                .filter(|unsafe_expr| !unsafe_expr.inside_unsafe_block)
-                .count()
-                == 0
-        {
-            return;
-        }
-
-        let (_, body_source) = db.body_with_source_map(def);
-        for unsafe_expr in unsafe_expressions {
-            if !unsafe_expr.inside_unsafe_block {
-                if let Ok(in_file) = body_source.as_ref().expr_syntax(unsafe_expr.expr) {
-                    self.sink.push(MissingUnsafe { file: in_file.file_id, expr: in_file.value })
-                }
-            }
-        }
-    }
+    unsafe_expressions(db, &infer, def)
+        .into_iter()
+        .filter(|it| !it.inside_unsafe_block)
+        .map(|it| it.expr)
+        .collect()
 }
 
-pub(crate) struct UnsafeExpr {
+struct UnsafeExpr {
     pub(crate) expr: ExprId,
     pub(crate) inside_unsafe_block: bool,
 }
 
-pub(crate) fn unsafe_expressions(
+fn unsafe_expressions(
     db: &dyn HirDatabase,
     infer: &InferenceResult,
     def: DefWithBodyId,
@@ -126,92 +96,3 @@ fn walk_unsafe(
         walk_unsafe(unsafe_exprs, db, infer, def, body, child, inside_unsafe_block);
     });
 }
-
-#[cfg(test)]
-mod tests {
-    use crate::diagnostics::tests::check_diagnostics;
-
-    #[test]
-    fn missing_unsafe_diagnostic_with_raw_ptr() {
-        check_diagnostics(
-            r#"
-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
-"#,
-        )
-    }
-
-    #[test]
-    fn missing_unsafe_diagnostic_with_unsafe_call() {
-        check_diagnostics(
-            r#"
-struct HasUnsafe;
-
-impl HasUnsafe {
-    unsafe fn unsafe_fn(&self) {
-        let x = &5 as *const usize;
-        let y = *x;
-    }
-}
-
-unsafe fn unsafe_fn() {
-    let x = &5 as *const usize;
-    let y = *x;
-}
-
-fn main() {
-    unsafe_fn();
-  //^^^^^^^^^^^ 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
-    unsafe {
-        unsafe_fn();
-        HasUnsafe.unsafe_fn();
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn missing_unsafe_diagnostic_with_static_mut() {
-        check_diagnostics(
-            r#"
-struct Ty {
-    a: u8,
-}
-
-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
-    unsafe {
-        let x = STATIC_MUT.a;
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn no_missing_unsafe_diagnostic_with_safe_intrinsic() {
-        check_diagnostics(
-            r#"
-extern "rust-intrinsic" {
-    pub fn bitreverse(x: u32) -> u32; // Safe intrinsic
-    pub fn floorf32(x: f32) -> f32; // Unsafe intrinsic
-}
-
-fn main() {
-    let _ = bitreverse(12);
-    let _ = floorf32(12.0);
-          //^^^^^^^^^^^^^^ This operation is unsafe and requires an unsafe function or block
-}
-"#,
-        );
-    }
-}
diff --git a/crates/hir_ty/src/diagnostics_sink.rs b/crates/hir_ty/src/diagnostics_sink.rs
deleted file mode 100644
index 084fa8b06..000000000
--- a/crates/hir_ty/src/diagnostics_sink.rs
+++ /dev/null
@@ -1,109 +0,0 @@
-//! Semantic errors and warnings.
-//!
-//! The `Diagnostic` trait defines a trait object which can represent any
-//! diagnostic.
-//!
-//! `DiagnosticSink` struct is used as an emitter for diagnostic. When creating
-//! a `DiagnosticSink`, you supply a callback which can react to a `dyn
-//! Diagnostic` or to any concrete diagnostic (downcasting is used internally).
-//!
-//! Because diagnostics store file offsets, it's a bad idea to store them
-//! directly in salsa. For this reason, every hir subsytem defines it's own
-//! strongly-typed closed set of diagnostics which use hir ids internally, are
-//! stored in salsa and do *not* implement the `Diagnostic` trait. Instead, a
-//! subsystem provides a separate, non-query-based API which can walk all stored
-//! values and transform them into instances of `Diagnostic`.
-
-use std::{any::Any, fmt};
-
-use hir_expand::InFile;
-use syntax::SyntaxNodePtr;
-
-#[derive(Copy, Clone, Debug, PartialEq)]
-pub struct DiagnosticCode(pub &'static str);
-
-impl DiagnosticCode {
-    pub fn as_str(&self) -> &str {
-        self.0
-    }
-}
-
-pub trait Diagnostic: Any + Send + Sync + fmt::Debug + 'static {
-    fn code(&self) -> DiagnosticCode;
-    fn message(&self) -> String;
-    /// Source element that triggered the diagnostics.
-    ///
-    /// Note that this should reflect "semantics", rather than specific span we
-    /// want to highlight. When rendering the diagnostics into an error message,
-    /// the IDE will fetch the `SyntaxNode` and will narrow the span
-    /// appropriately.
-    fn display_source(&self) -> InFile<SyntaxNodePtr>;
-    fn as_any(&self) -> &(dyn Any + Send + 'static);
-    fn is_experimental(&self) -> bool {
-        false
-    }
-}
-
-pub struct DiagnosticSink<'a> {
-    callbacks: Vec<Box<dyn FnMut(&dyn Diagnostic) -> Result<(), ()> + 'a>>,
-    filters: Vec<Box<dyn FnMut(&dyn Diagnostic) -> bool + 'a>>,
-    default_callback: Box<dyn FnMut(&dyn Diagnostic) + 'a>,
-}
-
-impl<'a> DiagnosticSink<'a> {
-    pub fn push(&mut self, d: impl Diagnostic) {
-        let d: &dyn Diagnostic = &d;
-        self._push(d);
-    }
-
-    fn _push(&mut self, d: &dyn Diagnostic) {
-        for filter in &mut self.filters {
-            if !filter(d) {
-                return;
-            }
-        }
-        for cb in &mut self.callbacks {
-            match cb(d) {
-                Ok(()) => return,
-                Err(()) => (),
-            }
-        }
-        (self.default_callback)(d)
-    }
-}
-
-pub struct DiagnosticSinkBuilder<'a> {
-    callbacks: Vec<Box<dyn FnMut(&dyn Diagnostic) -> Result<(), ()> + 'a>>,
-    filters: Vec<Box<dyn FnMut(&dyn Diagnostic) -> bool + 'a>>,
-}
-
-impl<'a> DiagnosticSinkBuilder<'a> {
-    pub fn new() -> Self {
-        Self { callbacks: Vec::new(), filters: Vec::new() }
-    }
-
-    pub fn filter<F: FnMut(&dyn Diagnostic) -> bool + 'a>(mut self, cb: F) -> Self {
-        self.filters.push(Box::new(cb));
-        self
-    }
-
-    pub fn on<D: Diagnostic, F: FnMut(&D) + 'a>(mut self, mut cb: F) -> Self {
-        let cb = move |diag: &dyn Diagnostic| match diag.as_any().downcast_ref::<D>() {
-            Some(d) => {
-                cb(d);
-                Ok(())
-            }
-            None => Err(()),
-        };
-        self.callbacks.push(Box::new(cb));
-        self
-    }
-
-    pub fn build<F: FnMut(&dyn Diagnostic) + 'a>(self, default_callback: F) -> DiagnosticSink<'a> {
-        DiagnosticSink {
-            callbacks: self.callbacks,
-            filters: self.filters,
-            default_callback: Box::new(default_callback),
-        }
-    }
-}
diff --git a/crates/hir_ty/src/infer.rs b/crates/hir_ty/src/infer.rs
index 0e9f777da..63f37c0ab 100644
--- a/crates/hir_ty/src/infer.rs
+++ b/crates/hir_ty/src/infer.rs
@@ -35,11 +35,9 @@ use stdx::impl_from;
 use syntax::SmolStr;
 
 use super::{DomainGoal, InEnvironment, ProjectionTy, TraitEnvironment, TraitRef, Ty};
-use crate::diagnostics_sink::DiagnosticSink;
 use crate::{
-    db::HirDatabase, fold_tys, infer::diagnostics::InferenceDiagnostic,
-    lower::ImplTraitLoweringMode, to_assoc_type_id, AliasEq, AliasTy, Goal, Interner, Substitution,
-    TyBuilder, TyExt, TyKind,
+    db::HirDatabase, fold_tys, lower::ImplTraitLoweringMode, to_assoc_type_id, AliasEq, AliasTy,
+    Goal, Interner, Substitution, TyBuilder, TyExt, TyKind,
 };
 
 // This lint has a false positive here. See the link below for details.
@@ -80,7 +78,7 @@ enum ExprOrPatId {
 impl_from!(ExprId, PatId for ExprOrPatId);
 
 /// Binding modes inferred for patterns.
-/// https://doc.rust-lang.org/reference/patterns.html#binding-modes
+/// <https://doc.rust-lang.org/reference/patterns.html#binding-modes>
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 enum BindingMode {
     Move,
@@ -111,6 +109,12 @@ pub(crate) struct InferOk {
 pub(crate) struct TypeError;
 pub(crate) type InferResult = Result<InferOk, TypeError>;
 
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum InferenceDiagnostic {
+    NoSuchField { expr: ExprId },
+    BreakOutsideOfLoop { expr: ExprId },
+}
+
 /// A mismatch between an expected and an inferred type.
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub struct TypeMismatch {
@@ -140,7 +144,7 @@ pub struct InferenceResult {
     variant_resolutions: FxHashMap<ExprOrPatId, VariantId>,
     /// For each associated item record what it resolves to
     assoc_resolutions: FxHashMap<ExprOrPatId, AssocItemId>,
-    diagnostics: Vec<InferenceDiagnostic>,
+    pub diagnostics: Vec<InferenceDiagnostic>,
     pub type_of_expr: ArenaMap<ExprId, Ty>,
     /// For each pattern record the type it resolves to.
     ///
@@ -191,14 +195,6 @@ impl InferenceResult {
             _ => None,
         })
     }
-    pub fn add_diagnostics(
-        &self,
-        db: &dyn HirDatabase,
-        owner: DefWithBodyId,
-        sink: &mut DiagnosticSink,
-    ) {
-        self.diagnostics.iter().for_each(|it| it.add_to(db, owner, sink))
-    }
 }
 
 impl Index<ExprId> for InferenceResult {
@@ -765,6 +761,38 @@ impl Expectation {
             Expectation::RValueLikeUnsized(_) | Expectation::None => None,
         }
     }
+
+    /// Comment copied from rustc:
+    /// Disregard "castable to" expectations because they
+    /// can lead us astray. Consider for example `if cond
+    /// {22} else {c} as u8` -- if we propagate the
+    /// "castable to u8" constraint to 22, it will pick the
+    /// type 22u8, which is overly constrained (c might not
+    /// be a u8). In effect, the problem is that the
+    /// "castable to" expectation is not the tightest thing
+    /// we can say, so we want to drop it in this case.
+    /// The tightest thing we can say is "must unify with
+    /// else branch". Note that in the case of a "has type"
+    /// constraint, this limitation does not hold.
+    ///
+    /// If the expected type is just a type variable, then don't use
+    /// an expected type. Otherwise, we might write parts of the type
+    /// when checking the 'then' block which are incompatible with the
+    /// 'else' branch.
+    fn adjust_for_branches(&self, table: &mut unify::InferenceTable) -> Expectation {
+        match self {
+            Expectation::HasType(ety) => {
+                let ety = table.resolve_ty_shallow(ety);
+                if !ety.is_ty_var() {
+                    Expectation::HasType(ety)
+                } else {
+                    Expectation::None
+                }
+            }
+            Expectation::RValueLikeUnsized(ety) => Expectation::RValueLikeUnsized(ety.clone()),
+            _ => Expectation::None,
+        }
+    }
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
@@ -804,43 +832,3 @@ impl std::ops::BitOrAssign for Diverges {
         *self = *self | other;
     }
 }
-
-mod diagnostics {
-    use hir_def::{expr::ExprId, DefWithBodyId};
-
-    use crate::{
-        db::HirDatabase,
-        diagnostics::{BreakOutsideOfLoop, NoSuchField},
-        diagnostics_sink::DiagnosticSink,
-    };
-
-    #[derive(Debug, PartialEq, Eq, Clone)]
-    pub(super) enum InferenceDiagnostic {
-        NoSuchField { expr: ExprId },
-        BreakOutsideOfLoop { expr: ExprId },
-    }
-
-    impl InferenceDiagnostic {
-        pub(super) fn add_to(
-            &self,
-            db: &dyn HirDatabase,
-            owner: DefWithBodyId,
-            sink: &mut DiagnosticSink,
-        ) {
-            match self {
-                InferenceDiagnostic::NoSuchField { expr } => {
-                    let (_, source_map) = db.body_with_source_map(owner);
-                    let field = source_map.field_syntax(*expr);
-                    sink.push(NoSuchField { file: field.file_id, field: field.value })
-                }
-                InferenceDiagnostic::BreakOutsideOfLoop { expr } => {
-                    let (_, source_map) = db.body_with_source_map(owner);
-                    let ptr = source_map
-                        .expr_syntax(*expr)
-                        .expect("break outside of loop in synthetic syntax");
-                    sink.push(BreakOutsideOfLoop { file: ptr.file_id, expr: ptr.value })
-                }
-            }
-        }
-    }
-}
diff --git a/crates/hir_ty/src/infer/coerce.rs b/crates/hir_ty/src/infer/coerce.rs
index 03b97e7db..4b7f31521 100644
--- a/crates/hir_ty/src/infer/coerce.rs
+++ b/crates/hir_ty/src/infer/coerce.rs
@@ -2,8 +2,8 @@
 //! happen in certain places, e.g. weakening `&mut` to `&` or deref coercions
 //! like going from `&Vec<T>` to `&[T]`.
 //!
-//! See https://doc.rust-lang.org/nomicon/coercions.html and
-//! librustc_typeck/check/coercion.rs.
+//! See <https://doc.rust-lang.org/nomicon/coercions.html> and
+//! `librustc_typeck/check/coercion.rs`.
 
 use chalk_ir::{cast::Cast, Mutability, TyVariableKind};
 use hir_def::{expr::ExprId, lang_item::LangItemTarget};
@@ -109,7 +109,7 @@ impl<'a> InferenceContext<'a> {
         }
 
         // Consider coercing the subtype to a DST
-        if let Ok(ret) = self.try_coerce_unsized(&from_ty, &to_ty) {
+        if let Ok(ret) = self.try_coerce_unsized(&from_ty, to_ty) {
             return Ok(ret);
         }
 
@@ -331,7 +331,7 @@ impl<'a> InferenceContext<'a> {
 
     /// Coerce a type using `from_ty: CoerceUnsized<ty_ty>`
     ///
-    /// See: https://doc.rust-lang.org/nightly/std/marker/trait.CoerceUnsized.html
+    /// See: <https://doc.rust-lang.org/nightly/std/marker/trait.CoerceUnsized.html>
     fn try_coerce_unsized(&mut self, from_ty: &Ty, to_ty: &Ty) -> InferResult {
         // These 'if' statements require some explanation.
         // The `CoerceUnsized` trait is special - it is only
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index f73bf43b2..5ea2e5934 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -54,7 +54,7 @@ impl<'a> InferenceContext<'a> {
     /// Infer type of expression with possibly implicit coerce to the expected type.
     /// Return the type after possible coercion.
     pub(super) fn infer_expr_coerce(&mut self, expr: ExprId, expected: &Expectation) -> Ty {
-        let ty = self.infer_expr_inner(expr, &expected);
+        let ty = self.infer_expr_inner(expr, expected);
         let ty = if let Some(target) = expected.only_has_type(&mut self.table) {
             if !self.coerce(&ty, &target) {
                 self.result
@@ -135,11 +135,11 @@ impl<'a> InferenceContext<'a> {
                 let mut both_arms_diverge = Diverges::Always;
 
                 let mut result_ty = self.table.new_type_var();
-                let then_ty = self.infer_expr_inner(*then_branch, &expected);
+                let then_ty = self.infer_expr_inner(*then_branch, expected);
                 both_arms_diverge &= mem::replace(&mut self.diverges, Diverges::Maybe);
                 result_ty = self.coerce_merge_branch(Some(*then_branch), &result_ty, &then_ty);
                 let else_ty = match else_branch {
-                    Some(else_branch) => self.infer_expr_inner(*else_branch, &expected),
+                    Some(else_branch) => self.infer_expr_inner(*else_branch, expected),
                     None => TyBuilder::unit(),
                 };
                 both_arms_diverge &= self.diverges;
@@ -327,20 +327,19 @@ impl<'a> InferenceContext<'a> {
                 self.normalize_associated_types_in(ret_ty)
             }
             Expr::MethodCall { receiver, args, method_name, generic_args } => self
-                .infer_method_call(
-                    tgt_expr,
-                    *receiver,
-                    &args,
-                    &method_name,
-                    generic_args.as_deref(),
-                ),
+                .infer_method_call(tgt_expr, *receiver, args, method_name, generic_args.as_deref()),
             Expr::Match { expr, arms } => {
                 let input_ty = self.infer_expr(*expr, &Expectation::none());
 
+                let expected = expected.adjust_for_branches(&mut self.table);
+
                 let mut result_ty = if arms.is_empty() {
                     TyKind::Never.intern(&Interner)
                 } else {
-                    self.table.new_type_var()
+                    match &expected {
+                        Expectation::HasType(ty) => ty.clone(),
+                        _ => self.table.new_type_var(),
+                    }
                 };
 
                 let matchee_diverges = self.diverges;
@@ -988,7 +987,7 @@ impl<'a> InferenceContext<'a> {
     }
 
     fn register_obligations_for_call(&mut self, callable_ty: &Ty) {
-        let callable_ty = self.resolve_ty_shallow(&callable_ty);
+        let callable_ty = self.resolve_ty_shallow(callable_ty);
         if let TyKind::FnDef(fn_def, parameters) = callable_ty.kind(&Interner) {
             let def: CallableDefId = from_chalk(self.db, *fn_def);
             let generic_predicates = self.db.generic_predicates(def.into());
diff --git a/crates/hir_ty/src/infer/pat.rs b/crates/hir_ty/src/infer/pat.rs
index 25dff7e49..035f4ded6 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(self.err_ty())
             }
             Pat::Bind { mode, name: _, subpat } => {
                 let mode = if mode == &BindingAnnotation::Unannotated {
@@ -275,7 +275,7 @@ impl<'a> InferenceContext<'a> {
         if !self.unify(&ty, &expected) {
             self.result
                 .type_mismatches
-                .insert(pat.into(), TypeMismatch { expected: expected, actual: ty.clone() });
+                .insert(pat.into(), TypeMismatch { expected, actual: ty.clone() });
         }
         self.write_pat_ty(pat, ty.clone());
         ty
diff --git a/crates/hir_ty/src/infer/path.rs b/crates/hir_ty/src/infer/path.rs
index 14c99eafd..056cdb5d5 100644
--- a/crates/hir_ty/src/infer/path.rs
+++ b/crates/hir_ty/src/infer/path.rs
@@ -43,11 +43,11 @@ impl<'a> InferenceContext<'a> {
             }
             let ty = self.make_ty(type_ref);
             let remaining_segments_for_ty = path.segments().take(path.segments().len() - 1);
-            let ctx = crate::lower::TyLoweringContext::new(self.db, &resolver);
+            let ctx = crate::lower::TyLoweringContext::new(self.db, resolver);
             let (ty, _) = ctx.lower_ty_relative_path(ty, None, remaining_segments_for_ty);
             self.resolve_ty_assoc_item(
                 ty,
-                &path.segments().last().expect("path had at least one segment").name,
+                path.segments().last().expect("path had at least one segment").name,
                 id,
             )?
         } else {
@@ -154,7 +154,7 @@ impl<'a> InferenceContext<'a> {
                 let segment =
                     remaining_segments.last().expect("there should be at least one segment here");
 
-                self.resolve_ty_assoc_item(ty, &segment.name, id)
+                self.resolve_ty_assoc_item(ty, segment.name, id)
             }
         }
     }
diff --git a/crates/hir_ty/src/interner.rs b/crates/hir_ty/src/interner.rs
index 29ffdd9b7..5fef878e8 100644
--- a/crates/hir_ty/src/interner.rs
+++ b/crates/hir_ty/src/interner.rs
@@ -331,7 +331,7 @@ impl chalk_ir::interner::Interner for Interner {
         &self,
         clauses: &'a Self::InternedProgramClauses,
     ) -> &'a [chalk_ir::ProgramClause<Self>] {
-        &clauses
+        clauses
     }
 
     fn intern_quantified_where_clauses<E>(
@@ -373,7 +373,7 @@ impl chalk_ir::interner::Interner for Interner {
         &self,
         canonical_var_kinds: &'a Self::InternedCanonicalVarKinds,
     ) -> &'a [chalk_ir::CanonicalVarKind<Self>] {
-        &canonical_var_kinds
+        canonical_var_kinds
     }
 
     fn intern_constraints<E>(
@@ -413,7 +413,7 @@ impl chalk_ir::interner::Interner for Interner {
         &self,
         variances: &'a Self::InternedVariances,
     ) -> &'a [chalk_ir::Variance] {
-        &variances
+        variances
     }
 }
 
diff --git a/crates/hir_ty/src/lib.rs b/crates/hir_ty/src/lib.rs
index 50e0d6333..128cae830 100644
--- a/crates/hir_ty/src/lib.rs
+++ b/crates/hir_ty/src/lib.rs
@@ -21,7 +21,6 @@ mod utils;
 mod walk;
 pub mod db;
 pub mod diagnostics;
-pub mod diagnostics_sink;
 pub mod display;
 pub mod method_resolution;
 pub mod primitive;
@@ -50,7 +49,7 @@ use crate::{db::HirDatabase, utils::generics};
 pub use autoderef::autoderef;
 pub use builder::TyBuilder;
 pub use chalk_ext::*;
-pub use infer::{could_unify, InferenceResult};
+pub use infer::{could_unify, InferenceDiagnostic, InferenceResult};
 pub use interner::Interner;
 pub use lower::{
     associated_type_shorthand_candidates, callable_item_sig, CallableDefId, ImplTraitLoweringMode,
diff --git a/crates/hir_ty/src/lower.rs b/crates/hir_ty/src/lower.rs
index c83933c73..817a65c20 100644
--- a/crates/hir_ty/src/lower.rs
+++ b/crates/hir_ty/src/lower.rs
@@ -238,7 +238,7 @@ impl<'a> TyLoweringContext<'a> {
                         // away instead of two.
                         let actual_opaque_type_data = self
                             .with_debruijn(DebruijnIndex::INNERMOST, |ctx| {
-                                ctx.lower_impl_trait(&bounds)
+                                ctx.lower_impl_trait(bounds)
                             });
                         self.opaque_type_data.borrow_mut()[idx as usize] = actual_opaque_type_data;
 
@@ -421,7 +421,7 @@ impl<'a> TyLoweringContext<'a> {
                     let found = self
                         .db
                         .trait_data(trait_ref.hir_trait_id())
-                        .associated_type_by_name(&segment.name);
+                        .associated_type_by_name(segment.name);
                     match found {
                         Some(associated_ty) => {
                             // FIXME handle type parameters on the segment
@@ -505,7 +505,7 @@ impl<'a> TyLoweringContext<'a> {
     pub(crate) fn lower_path(&self, path: &Path) -> (Ty, Option<TypeNs>) {
         // Resolve the path (in type namespace)
         if let Some(type_ref) = path.type_anchor() {
-            let (ty, res) = self.lower_ty_ext(&type_ref);
+            let (ty, res) = self.lower_ty_ext(type_ref);
             return self.lower_ty_relative_path(ty, res, path.segments());
         }
         let (resolution, remaining_index) =
@@ -784,7 +784,7 @@ impl<'a> TyLoweringContext<'a> {
         let trait_ref = match bound {
             TypeBound::Path(path) => {
                 bindings = self.lower_trait_ref_from_path(path, Some(self_ty));
-                bindings.clone().map(WhereClause::Implemented).map(|b| crate::wrap_empty_binders(b))
+                bindings.clone().map(WhereClause::Implemented).map(crate::wrap_empty_binders)
             }
             TypeBound::Lifetime(_) => None,
             TypeBound::Error => None,
@@ -957,7 +957,7 @@ pub(crate) fn field_types_query(
 /// like `T::Item`.
 ///
 /// See the analogous query in rustc and its comment:
-/// https://github.com/rust-lang/rust/blob/9150f844e2624eb013ec78ca08c1d416e6644026/src/librustc_typeck/astconv.rs#L46
+/// <https://github.com/rust-lang/rust/blob/9150f844e2624eb013ec78ca08c1d416e6644026/src/librustc_typeck/astconv.rs#L46>
 /// This is a query mostly to handle cycles somewhat gracefully; e.g. the
 /// following bounds are disallowed: `T: Foo<U::Item>, U: Foo<T::Item>`, but
 /// these are fine: `T: Foo<U::Item>, U: Foo<()>`.
diff --git a/crates/hir_ty/src/method_resolution.rs b/crates/hir_ty/src/method_resolution.rs
index a23527f7d..3d233b1e2 100644
--- a/crates/hir_ty/src/method_resolution.rs
+++ b/crates/hir_ty/src/method_resolution.rs
@@ -8,7 +8,7 @@ use arrayvec::ArrayVec;
 use base_db::{CrateId, Edition};
 use chalk_ir::{cast::Cast, Mutability, UniverseIndex};
 use hir_def::{
-    lang_item::LangItemTarget, nameres::DefMap, AssocContainerId, AssocItemId, FunctionId,
+    lang_item::LangItemTarget, nameres::DefMap, AssocContainerId, AssocItemId, BlockId, FunctionId,
     GenericDefId, HasModule, ImplId, Lookup, ModuleId, TraitId,
 };
 use hir_expand::name::Name;
@@ -60,7 +60,7 @@ impl TyFingerprint {
             TyKind::Adt(AdtId(adt), _) => TyFingerprint::Adt(*adt),
             TyKind::Raw(mutability, ..) => TyFingerprint::RawPtr(*mutability),
             TyKind::Foreign(alias_id, ..) => TyFingerprint::ForeignType(*alias_id),
-            TyKind::Dyn(_) => ty.dyn_trait().map(|trait_| TyFingerprint::Dyn(trait_))?,
+            TyKind::Dyn(_) => ty.dyn_trait().map(TyFingerprint::Dyn)?,
             _ => return None,
         };
         Some(fp)
@@ -77,7 +77,7 @@ impl TyFingerprint {
             TyKind::Adt(AdtId(adt), _) => TyFingerprint::Adt(*adt),
             TyKind::Raw(mutability, ..) => TyFingerprint::RawPtr(*mutability),
             TyKind::Foreign(alias_id, ..) => TyFingerprint::ForeignType(*alias_id),
-            TyKind::Dyn(_) => ty.dyn_trait().map(|trait_| TyFingerprint::Dyn(trait_))?,
+            TyKind::Dyn(_) => ty.dyn_trait().map(TyFingerprint::Dyn)?,
             TyKind::Ref(_, _, ty) => return TyFingerprint::for_trait_impl(ty),
             TyKind::Tuple(_, subst) => {
                 let first_ty = subst.interned().get(0).map(|arg| arg.assert_ty_ref(&Interner));
@@ -139,35 +139,47 @@ impl TraitImpls {
         let mut impls = Self { map: FxHashMap::default() };
 
         let crate_def_map = db.crate_def_map(krate);
-        collect_def_map(db, &crate_def_map, &mut impls);
+        impls.collect_def_map(db, &crate_def_map);
 
         return Arc::new(impls);
+    }
 
-        fn collect_def_map(db: &dyn HirDatabase, def_map: &DefMap, impls: &mut TraitImpls) {
-            for (_module_id, module_data) in def_map.modules() {
-                for impl_id in module_data.scope.impls() {
-                    let target_trait = match db.impl_trait(impl_id) {
-                        Some(tr) => tr.skip_binders().hir_trait_id(),
-                        None => continue,
-                    };
-                    let self_ty = db.impl_self_ty(impl_id);
-                    let self_ty_fp = TyFingerprint::for_trait_impl(self_ty.skip_binders());
-                    impls
-                        .map
-                        .entry(target_trait)
-                        .or_default()
-                        .entry(self_ty_fp)
-                        .or_default()
-                        .push(impl_id);
-                }
+    pub(crate) fn trait_impls_in_block_query(
+        db: &dyn HirDatabase,
+        block: BlockId,
+    ) -> Option<Arc<Self>> {
+        let _p = profile::span("trait_impls_in_block_query");
+        let mut impls = Self { map: FxHashMap::default() };
 
-                // To better support custom derives, collect impls in all unnamed const items.
-                // const _: () = { ... };
-                for konst in module_data.scope.unnamed_consts() {
-                    let body = db.body(konst.into());
-                    for (_, block_def_map) in body.blocks(db.upcast()) {
-                        collect_def_map(db, &block_def_map, impls);
-                    }
+        let block_def_map = db.block_def_map(block)?;
+        impls.collect_def_map(db, &block_def_map);
+
+        return Some(Arc::new(impls));
+    }
+
+    fn collect_def_map(&mut self, db: &dyn HirDatabase, def_map: &DefMap) {
+        for (_module_id, module_data) in def_map.modules() {
+            for impl_id in module_data.scope.impls() {
+                let target_trait = match db.impl_trait(impl_id) {
+                    Some(tr) => tr.skip_binders().hir_trait_id(),
+                    None => continue,
+                };
+                let self_ty = db.impl_self_ty(impl_id);
+                let self_ty_fp = TyFingerprint::for_trait_impl(self_ty.skip_binders());
+                self.map
+                    .entry(target_trait)
+                    .or_default()
+                    .entry(self_ty_fp)
+                    .or_default()
+                    .push(impl_id);
+            }
+
+            // To better support custom derives, collect impls in all unnamed const items.
+            // const _: () = { ... };
+            for konst in module_data.scope.unnamed_consts() {
+                let body = db.body(konst.into());
+                for (_, block_def_map) in body.blocks(db.upcast()) {
+                    self.collect_def_map(db, &block_def_map);
                 }
             }
         }
@@ -372,7 +384,7 @@ pub(crate) fn lookup_method(
         db,
         env,
         krate,
-        &traits_in_scope,
+        traits_in_scope,
         visible_from_module,
         Some(name),
         LookupMode::MethodCall,
@@ -484,7 +496,7 @@ fn iterate_method_candidates_impl(
         LookupMode::Path => {
             // No autoderef for path lookups
             iterate_method_candidates_for_self_ty(
-                &ty,
+                ty,
                 db,
                 env,
                 krate,
@@ -513,7 +525,7 @@ fn iterate_method_candidates_with_autoref(
         db,
         env.clone(),
         krate,
-        &traits_in_scope,
+        traits_in_scope,
         visible_from_module,
         name,
         &mut callback,
@@ -531,7 +543,7 @@ fn iterate_method_candidates_with_autoref(
         db,
         env.clone(),
         krate,
-        &traits_in_scope,
+        traits_in_scope,
         visible_from_module,
         name,
         &mut callback,
@@ -549,7 +561,7 @@ fn iterate_method_candidates_with_autoref(
         db,
         env,
         krate,
-        &traits_in_scope,
+        traits_in_scope,
         visible_from_module,
         name,
         &mut callback,
@@ -593,7 +605,7 @@ fn iterate_method_candidates_by_receiver(
             db,
             env.clone(),
             krate,
-            &traits_in_scope,
+            traits_in_scope,
             name,
             Some(receiver_ty),
             &mut callback,
@@ -870,7 +882,7 @@ fn transform_receiver_ty(
             .fill_with_unknown()
             .build(),
         AssocContainerId::ImplId(impl_id) => {
-            let impl_substs = inherent_impl_substs(db, env, impl_id, &self_ty)?;
+            let impl_substs = inherent_impl_substs(db, env, impl_id, self_ty)?;
             TyBuilder::subst_for_def(db, function_id)
                 .use_parent_substs(&impl_substs)
                 .fill_with_unknown()
diff --git a/crates/hir_ty/src/tests.rs b/crates/hir_ty/src/tests.rs
index 9d726b024..b873585c4 100644
--- a/crates/hir_ty/src/tests.rs
+++ b/crates/hir_ty/src/tests.rs
@@ -9,7 +9,7 @@ mod macros;
 mod display_source_code;
 mod incremental;
 
-use std::{env, sync::Arc};
+use std::{collections::HashMap, env, sync::Arc};
 
 use base_db::{fixture::WithFixture, FileRange, SourceDatabase, SourceDatabaseExt};
 use expect_test::Expect;
@@ -83,9 +83,105 @@ fn check_types_impl(ra_fixture: &str, display_source: bool) {
             checked_one = true;
         }
     }
+
     assert!(checked_one, "no `//^` annotations found");
 }
 
+fn check_no_mismatches(ra_fixture: &str) {
+    check_mismatches_impl(ra_fixture, true)
+}
+
+#[allow(unused)]
+fn check_mismatches(ra_fixture: &str) {
+    check_mismatches_impl(ra_fixture, false)
+}
+
+fn check_mismatches_impl(ra_fixture: &str, allow_none: 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 mut defs: Vec<DefWithBodyId> = Vec::new();
+    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);
+            loc.source(&db).value.syntax().text_range().start()
+        }
+        DefWithBodyId::ConstId(it) => {
+            let loc = it.lookup(&db);
+            loc.source(&db).value.syntax().text_range().start()
+        }
+        DefWithBodyId::StaticId(it) => {
+            let loc = it.lookup(&db);
+            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);
+    };
+    for def in defs {
+        let (_body, body_source_map) = db.body_with_source_map(def);
+        let inference_result = db.infer(def);
+        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,
+            };
+            push_mismatch(syntax_ptr, mismatch.clone());
+        }
+        for (expr, mismatch) in inference_result.expr_type_mismatches() {
+            let node = 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) => 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);
+            } else {
+                assert!(false, "Expected mismatch not encountered: {}\n", expected);
+            }
+            checked_one = true;
+        }
+    }
+    let mut buf = String::new();
+    for (range, mismatch) in mismatches {
+        format_to!(buf, "{:?}: {}\n", range.range, mismatch,);
+    }
+    assert!(buf.is_empty(), "Unexpected type mismatches:\n{}", buf);
+
+    assert!(checked_one || allow_none, "no `//^` annotations found");
+}
+
 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();
diff --git a/crates/hir_ty/src/tests/coercion.rs b/crates/hir_ty/src/tests/coercion.rs
index 6dac7e103..713b74165 100644
--- a/crates/hir_ty/src/tests/coercion.rs
+++ b/crates/hir_ty/src/tests/coercion.rs
@@ -1,6 +1,6 @@
 use expect_test::expect;
 
-use super::{check_infer, check_infer_with_mismatches, check_types};
+use super::{check_infer, check_infer_with_mismatches, check_no_mismatches, check_types};
 
 #[test]
 fn infer_block_expr_type_mismatch() {
@@ -23,38 +23,29 @@ fn infer_block_expr_type_mismatch() {
 fn coerce_places() {
     check_infer(
         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 {}
-        "#,
+    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);
+}
+"#,
         expect![[r#"
             30..31 '_': &[T]
             44..55 '{ loop {} }': T
@@ -131,60 +122,52 @@ fn infer_let_stmt_coerce() {
 fn infer_custom_coerce_unsized() {
     check_infer(
         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 }
-
-        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);
-        }
+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 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 {}
-        "#,
+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);
+}
+"#,
         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]>
+            306..307 'x': A<[T]>
+            327..332 '{ x }': A<[T]>
+            329..330 'x': A<[T]>
+            344..345 'x': B<[T]>
+            365..370 '{ x }': B<[T]>
+            367..368 'x': B<[T]>
+            382..383 'x': C<[T]>
+            403..408 '{ x }': C<[T]>
+            405..406 'x': C<[T]>
+            418..419 'a': A<[u8; 2]>
+            433..434 'b': B<[u8; 2]>
+            448..449 'c': C<[u8; 2]>
+            463..529 '{     ...(c); }': ()
+            473..474 'd': A<[{unknown}]>
+            477..481 'foo1': fn foo1<{unknown}>(A<[{unknown}]>) -> A<[{unknown}]>
+            477..484 'foo1(a)': A<[{unknown}]>
+            482..483 'a': A<[u8; 2]>
+            494..495 'e': B<[u8]>
+            498..502 'foo2': fn foo2<u8>(B<[u8]>) -> B<[u8]>
+            498..505 'foo2(b)': B<[u8]>
+            503..504 'b': B<[u8; 2]>
+            515..516 'f': C<[u8]>
+            519..523 'foo3': fn foo3<u8>(C<[u8]>) -> C<[u8]>
+            519..526 'foo3(c)': C<[u8]>
+            524..525 'c': C<[u8; 2]>
         "#]],
     );
 }
@@ -193,21 +176,16 @@ fn infer_custom_coerce_unsized() {
 fn infer_if_coerce() {
     check_infer(
         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> {}
-        "#,
+//- minicore: unsize
+fn foo<T>(x: &[T]) -> &[T] { loop {} }
+fn test() {
+    let x = if true {
+        foo(&[1])
+    } else {
+        &[1]
+    };
+}
+"#,
         expect![[r#"
             10..11 'x': &[T]
             27..38 '{ loop {} }': &[T]
@@ -235,25 +213,16 @@ fn infer_if_coerce() {
 fn infer_if_else_coerce() {
     check_infer(
         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 {}
-        "#,
+//- minicore: coerce_unsized
+fn foo<T>(x: &[T]) -> &[T] { loop {} }
+fn test() {
+    let x = if true {
+        &[1]
+    } else {
+        foo(&[1])
+    };
+}
+"#,
         expect![[r#"
             10..11 'x': &[T]
             27..38 '{ loop {} }': &[T]
@@ -281,20 +250,16 @@ fn infer_if_else_coerce() {
 fn infer_match_first_coerce() {
     check_infer(
         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> {}
-        "#,
+//- minicore: unsize
+fn foo<T>(x: &[T]) -> &[T] { loop {} }
+fn test(i: i32) {
+    let x = match i {
+        2 => foo(&[2]),
+        1 => &[1],
+        _ => &[3],
+    };
+}
+"#,
         expect![[r#"
             10..11 'x': &[T]
             27..38 '{ loop {} }': &[T]
@@ -329,25 +294,16 @@ fn infer_match_first_coerce() {
 fn infer_match_second_coerce() {
     check_infer(
         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 {}
-        "#,
+//- minicore: coerce_unsized
+fn foo<T>(x: &[T]) -> &[T] { loop {} }
+fn test(i: i32) {
+    let x = match i {
+        1 => &[1],
+        2 => foo(&[2]),
+        _ => &[3],
+    };
+}
+"#,
         expect![[r#"
             10..11 'x': &[T]
             27..38 '{ loop {} }': &[T]
@@ -470,15 +426,15 @@ fn coerce_autoderef() {
 #[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);
-        }
-        ",
+        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
@@ -508,30 +464,29 @@ fn coerce_autoderef_generic() {
 fn coerce_autoderef_block() {
     check_infer_with_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() });
+}
+"#,
+        expect![[r#"
+            90..91 'x': &str
+            99..101 '{}': ()
+            132..143 '{ loop {} }': String
+            134..141 'loop {}': !
+            139..141 '{}': ()
+            154..199 '{     ... }); }': ()
+            160..173 'takes_ref_str': fn takes_ref_str(&str)
+            160..196 'takes_...g() })': ()
+            174..195 '&{ ret...ng() }': &String
+            175..195 '{ retu...ng() }': String
+            177..191 'returns_string': fn returns_string() -> String
+            177..193 'return...ring()': String
+        "#]],
     );
 }
 
@@ -674,25 +629,19 @@ fn coerce_placeholder_ref() {
 fn coerce_unsize_array() {
     check_infer_with_mismatches(
         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];
-        }
+//- minicore: coerce_unsized
+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
+            10..47 '{     ... 3]; }': ()
+            20..21 'f': &[usize]
+            34..44 '&[1, 2, 3]': &[usize; 3]
+            35..44 '[1, 2, 3]': [usize; 3]
+            36..37 '1': usize
+            39..40 '2': usize
+            42..43 '3': usize
         "#]],
     );
 }
@@ -701,93 +650,94 @@ fn coerce_unsize_array() {
 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}>
-        "]],
+//- 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;
+    let obj: &dyn Bar<_, i8, i16> = &S;
+    let obj: &dyn Foo<i8, _> = &S;
+}
+"#,
+        expect![[r#"
+            236..351 '{     ... &S; }': ()
+            246..249 'obj': &dyn Baz<i8, i16>
+            271..273 '&S': &S<i8, i16>
+            272..273 'S': S<i8, i16>
+            283..286 'obj': &dyn Bar<usize, i8, i16>
+            311..313 '&S': &S<i8, i16>
+            312..313 'S': S<i8, i16>
+            323..326 'obj': &dyn Foo<i8, usize>
+            346..348 '&S': &S<i8, {unknown}>
+            347..348 '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() {
+    // FIXME: The rust reference says this should be possible, but rustc doesn't
+    // implement it. We used to support it, but Chalk doesn't. Here's the
+    // correct expect:
+    //
+    //     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>
     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<_, _, _> = 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;
+    let obj: &dyn Bar<_, _, _> = obj;
+    let obj: &dyn Foo<_, _> = obj;
+    let obj2: &dyn Baz<i8, i16> = &S;
+    let _: &dyn Foo<_, _> = obj2;
+}
+"#,
+        expect![[r#"
+            236..421 '{     ...bj2; }': ()
+            246..249 'obj': &dyn Baz<i8, i16>
+            271..273 '&S': &S<i8, i16>
+            272..273 'S': S<i8, i16>
+            283..286 'obj': &dyn Bar<{unknown}, {unknown}, {unknown}>
+            308..311 'obj': &dyn Baz<i8, i16>
+            321..324 'obj': &dyn Foo<{unknown}, {unknown}>
+            343..346 'obj': &dyn Bar<{unknown}, {unknown}, {unknown}>
+            356..360 'obj2': &dyn Baz<i8, i16>
+            382..384 '&S': &S<i8, i16>
+            383..384 'S': S<i8, i16>
+            394..395 '_': &dyn Foo<{unknown}, {unknown}>
+            414..418 'obj2': &dyn Baz<i8, i16>
+            308..311: expected &dyn Bar<{unknown}, {unknown}, {unknown}>, got &dyn Baz<i8, i16>
+            343..346: expected &dyn Foo<{unknown}, {unknown}>, got &dyn Bar<{unknown}, {unknown}, {unknown}>
+            414..418: expected &dyn Foo<{unknown}, {unknown}>, got &dyn Baz<i8, i16>
+        "#]],
     );
 }
 
@@ -795,40 +745,32 @@ fn coerce_unsize_trait_object_to_trait_object() {
 fn coerce_unsize_super_trait_cycle() {
     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 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;
+}
+"#,
+        expect![[r#"
+            140..195 '{     ... &S; }': ()
+            150..153 'obj': &dyn D
+            164..166 '&S': &S
+            165..166 'S': S
+            176..179 'obj': &dyn A
+            190..192 '&S': &S
+            191..192 'S': S
+        "#]],
     );
 }
 
@@ -837,41 +779,35 @@ fn coerce_unsize_generic() {
     // FIXME: fix the type mismatches here
     check_infer_with_mismatches(
         r#"
-        #[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
+struct Foo<T> { t: T };
+struct Bar<T>(Foo<T>);
 
-        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] });
-        }
-        "#,
+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]>
+            58..166 '{     ... }); }': ()
+            68..69 '_': &Foo<[usize]>
+            87..108 '&Foo {..., 3] }': &Foo<[usize]>
+            88..108 'Foo { ..., 3] }': Foo<[usize]>
+            97..106 '[1, 2, 3]': [usize; 3]
+            98..99 '1': usize
+            101..102 '2': usize
+            104..105 '3': usize
+            118..119 '_': &Bar<[usize]>
+            137..163 '&Bar(F... 3] })': &Bar<[i32; 3]>
+            138..141 'Bar': Bar<[i32; 3]>(Foo<[i32; 3]>) -> Bar<[i32; 3]>
+            138..163 'Bar(Fo... 3] })': Bar<[i32; 3]>
+            142..162 'Foo { ..., 3] }': Foo<[i32; 3]>
+            151..160 '[1, 2, 3]': [i32; 3]
+            152..153 '1': i32
+            155..156 '2': i32
+            158..159 '3': i32
+            97..106: expected [usize], got [usize; 3]
+            137..163: expected &Bar<[usize]>, got &Bar<[i32; 3]>
         "#]],
     );
 }
@@ -881,15 +817,7 @@ fn coerce_unsize_apit() {
     // FIXME: #8984
     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 {}
-
+//- minicore: coerce_unsized
 trait Foo {}
 
 fn test(f: impl Foo) {
@@ -897,12 +825,12 @@ fn test(f: 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
+            22..23 'f': impl Foo
+            35..64 '{     ... &f; }': ()
+            45..46 '_': &dyn Foo
+            59..61 '&f': &impl Foo
+            60..61 'f': impl Foo
+            59..61: expected &dyn Foo, got &impl Foo
         "#]],
     );
 }
@@ -963,7 +891,7 @@ fn test() -> i32 {
 
 #[test]
 fn panic_macro() {
-    check_infer_with_mismatches(
+    check_no_mismatches(
         r#"
 mod panic {
     #[macro_export]
@@ -991,15 +919,26 @@ fn main() {
     panic!()
 }
         "#,
-        expect![[r#"
-            174..185 '{ loop {} }': !
-            176..183 'loop {}': !
-            181..183 '{}': ()
-            !0..24 '$crate...:panic': fn panic() -> !
-            !0..26 '$crate...anic()': !
-            !0..26 '$crate...anic()': !
-            !0..28 '$crate...015!()': !
-            454..470 '{     ...c!() }': ()
-        "#]],
+    );
+}
+
+#[test]
+fn coerce_unsize_expected_type() {
+    check_no_mismatches(
+        r#"
+//- minicore: coerce_unsized
+fn main() {
+    let foo: &[u32] = &[1, 2];
+    let foo: &[u32] = match true {
+        true => &[1, 2],
+        false => &[1, 2, 3],
+    };
+    let foo: &[u32] = if true {
+        &[1, 2]
+    } else {
+        &[1, 2, 3]
+    };
+}
+        "#,
     );
 }
diff --git a/crates/hir_ty/src/tests/method_resolution.rs b/crates/hir_ty/src/tests/method_resolution.rs
index f26b2c8a7..d9b5ee9cf 100644
--- a/crates/hir_ty/src/tests/method_resolution.rs
+++ b/crates/hir_ty/src/tests/method_resolution.rs
@@ -780,10 +780,7 @@ 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();
@@ -1178,11 +1175,7 @@ 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 +1184,7 @@ 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 +1198,21 @@ 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 +1222,7 @@ 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 +1239,7 @@ 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 +1253,29 @@ 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
         "#]],
     )
 }
diff --git a/crates/hir_ty/src/tests/patterns.rs b/crates/hir_ty/src/tests/patterns.rs
index 7d00cee9b..5adbe9c45 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_types};
+use super::{check_infer, check_infer_with_mismatches, check_mismatches, check_types};
 
 #[test]
 fn infer_pattern() {
@@ -518,47 +518,24 @@ fn infer_generics_in_patterns() {
 
 #[test]
 fn infer_const_pattern() {
-    check_infer_with_mismatches(
+    check_mismatches(
         r#"
-        enum Option<T> { None }
-        use Option::None;
-        struct Foo;
-        const Bar: usize = 1;
-
-        fn test() {
-            let a: Option<u32> = None;
-            let b: Option<i64> = match a {
-                None => None,
-            };
-            let _: () = match () { Foo => Foo }; // Expected mismatch
-            let _: () = match () { Bar => Bar }; // Expected mismatch
-        }
+enum Option<T> { None }
+use Option::None;
+struct Foo;
+const Bar: usize = 1;
+
+fn test() {
+    let a: Option<u32> = None;
+    let b: Option<i64> = match a {
+        None => None,
+    };
+    let _: () = match () { Foo => () };
+                        // ^^^ expected (), got Foo
+    let _: () = match () { Bar => () };
+                        // ^^^ expected (), got usize
+}
         "#,
-        expect![[r#"
-            73..74 '1': usize
-            87..309 '{     ...atch }': ()
-            97..98 'a': Option<u32>
-            114..118 'None': Option<u32>
-            128..129 'b': Option<i64>
-            145..182 'match ...     }': Option<i64>
-            151..152 'a': Option<u32>
-            163..167 'None': Option<u32>
-            171..175 'None': Option<i64>
-            192..193 '_': ()
-            200..223 'match ... Foo }': Foo
-            206..208 '()': ()
-            211..214 'Foo': Foo
-            218..221 'Foo': Foo
-            254..255 '_': ()
-            262..285 'match ... Bar }': usize
-            268..270 '()': ()
-            273..276 'Bar': usize
-            280..283 'Bar': usize
-            200..223: expected (), got Foo
-            211..214: expected (), got Foo
-            262..285: expected (), got usize
-            273..276: expected (), got usize
-        "#]],
     );
 }
 
@@ -594,48 +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..1edec1615 100644
--- a/crates/hir_ty/src/tests/regression.rs
+++ b/crates/hir_ty/src/tests/regression.rs
@@ -884,41 +884,37 @@ 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 +923,33 @@ 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 +971,33 @@ 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..68776f3c0 100644
--- a/crates/hir_ty/src/tests/simple.rs
+++ b/crates/hir_ty/src/tests/simple.rs
@@ -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,
-    }
-}
 "#,
     );
 }
@@ -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;
-        }
-
-        struct A<T>(T);
+//- minicore: deref
+use core::ops::Deref;
+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
@@ -2639,11 +2606,8 @@ 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 +2639,39 @@ 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>
         "#]],
     );
 }
diff --git a/crates/hir_ty/src/tests/traits.rs b/crates/hir_ty/src/tests/traits.rs
index 588f0d1d4..065cca74f 100644
--- a/crates/hir_ty/src/tests/traits.rs
+++ b/crates/hir_ty/src/tests/traits.rs
@@ -6,10 +6,10 @@ use super::{check_infer, check_infer_with_mismatches, check_types};
 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 +18,6 @@ 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 +26,14 @@ 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 +42,13 @@ 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 +57,7 @@ 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 +69,7 @@ async fn test() {
     b;
 //  ^ ()
     let c = async {
-        let y = Option::None;
+        let y = None;
         y
     //  ^ Option<u64>
     };
@@ -109,18 +77,6 @@ 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;
-    }
-}
-
 "#,
     );
 }
@@ -704,14 +660,9 @@ 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;
 }
 
@@ -731,16 +682,10 @@ 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> {
+impl<T> core::ops::Deref for Arc<T> {
     type Target = T;
 }
 
@@ -761,15 +706,10 @@ 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;
 }
 
@@ -784,14 +724,9 @@ 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;
 }
 
@@ -1475,7 +1410,6 @@ fn test(
 }
 
 #[test]
-#[ignore]
 fn error_bound_chalk() {
     check_types(
         r#"
@@ -1912,11 +1846,7 @@ 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 +1859,34 @@ 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 +1960,7 @@ 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 +1979,62 @@ 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
         "#]],
     );
 }
@@ -2117,11 +2043,7 @@ 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 {}
@@ -2560,12 +2482,7 @@ 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 +2501,15 @@ 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': &()
         "#]],
     );
 }
@@ -2626,12 +2543,9 @@ 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 {
@@ -2668,17 +2582,7 @@ 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 +2642,46 @@ 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
         "#]],
     );
 }
@@ -3064,45 +2968,23 @@ 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>
         "#]],
     );
 }
@@ -3181,17 +3063,7 @@ 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 +3076,7 @@ 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();
@@ -3644,20 +3511,16 @@ 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 +3559,7 @@ 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 {
@@ -3728,13 +3582,71 @@ async fn get_accounts() -> Result<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_types(
+        r#"
+trait Trait<T> {
+    fn foo(&self) -> T;
+}
+
+fn test() {
+    struct S;
+    impl Trait<u32> for S {
+        fn foo(&self) { 0 }
+    }
+
+    S.foo();
+ // ^^^^^^^ u32
+}
+"#,
+    );
+}
+
+#[test]
+fn local_impl_2() {
+    check_types(
+        r#"
+struct S;
+
+fn test() {
+    trait Trait<T> {
+        fn foo(&self) -> T;
+    }
+    impl Trait<u32> for S {
+        fn foo(&self) { 0 }
+    }
+
+    S.foo();
+ // ^^^^^^^ u32
+}
+"#,
+    );
+}
+
+#[test]
+fn local_impl_3() {
+    check_types(
+        r#"
+trait Trait<T> {
+    fn foo(&self) -> T;
+}
+
+fn test() {
+    struct S1;
+    {
+        struct S2;
+
+        impl Trait<S1> for S2 {
+            fn foo(&self) { S1 }
+        }
+
+        S2.foo();
+     // ^^^^^^^^ S1
     }
 }
 "#,
diff --git a/crates/ide/Cargo.toml b/crates/ide/Cargo.toml
index 88f3d09d3..0e8447394 100644
--- a/crates/ide/Cargo.toml
+++ b/crates/ide/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = { version = "1.1", features = ["thread-local"] }
+cov-mark = "2.0.0-pre.1"
 either = "1.5.3"
 indexmap = "1.4.0"
 itertools = "0.10.0"
@@ -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" }
 
@@ -39,4 +40,3 @@ hir = { path = "../hir", version = "0.0.0" }
 [dev-dependencies]
 test_utils = { path = "../test_utils" }
 expect-test = "1.1"
-cov-mark = "1.1.0"
diff --git a/crates/ide/src/diagnostics.rs b/crates/ide/src/diagnostics.rs
deleted file mode 100644
index d5c954b8b..000000000
--- a/crates/ide/src/diagnostics.rs
+++ /dev/null
@@ -1,722 +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 fixes;
-mod field_shorthand;
-mod unlinked_file;
-
-use std::cell::RefCell;
-
-use hir::{
-    db::AstDatabase,
-    diagnostics::{Diagnostic as _, DiagnosticCode, DiagnosticSinkBuilder},
-    InFile, 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, SyntaxNodePtr, TextRange, TextSize,
-};
-use text_edit::TextEdit;
-use unlinked_file::UnlinkedFile;
-
-use crate::{Assist, AssistId, AssistKind, FileId, Label, SourceChange};
-
-use self::fixes::DiagnosticWithFixes;
-
-#[derive(Debug)]
-pub struct Diagnostic {
-    // pub name: Option<String>,
-    pub message: String,
-    pub range: TextRange,
-    pub severity: Severity,
-    pub fixes: Option<Vec<Assist>>,
-    pub unused: bool,
-    pub code: Option<DiagnosticCode>,
-}
-
-impl Diagnostic {
-    fn error(range: TextRange, message: String) -> Self {
-        Self { message, range, severity: Severity::Error, fixes: None, unused: false, code: None }
-    }
-
-    fn hint(range: TextRange, message: String) -> Self {
-        Self {
-            message,
-            range,
-            severity: Severity::WeakWarning,
-            fixes: None,
-            unused: false,
-            code: None,
-        }
-    }
-
-    fn with_fixes(self, fixes: Option<Vec<Assist>>) -> Self {
-        Self { fixes, ..self }
-    }
-
-    fn with_unused(self, unused: bool) -> Self {
-        Self { unused, ..self }
-    }
-
-    fn with_code(self, code: Option<DiagnosticCode>) -> Self {
-        Self { code, ..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>,
-}
-
-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::error(err.range(), format!("Syntax Error: {}", err))),
-    );
-
-    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 res = RefCell::new(res);
-    let sink_builder = DiagnosticSinkBuilder::new()
-        .on::<hir::diagnostics::UnresolvedModule, _>(|d| {
-            res.borrow_mut().push(diagnostic_with_fix(d, &sema, resolve));
-        })
-        .on::<hir::diagnostics::MissingFields, _>(|d| {
-            res.borrow_mut().push(diagnostic_with_fix(d, &sema, resolve));
-        })
-        .on::<hir::diagnostics::MissingOkOrSomeInTailExpr, _>(|d| {
-            res.borrow_mut().push(diagnostic_with_fix(d, &sema, resolve));
-        })
-        .on::<hir::diagnostics::NoSuchField, _>(|d| {
-            res.borrow_mut().push(diagnostic_with_fix(d, &sema, resolve));
-        })
-        .on::<hir::diagnostics::RemoveThisSemicolon, _>(|d| {
-            res.borrow_mut().push(diagnostic_with_fix(d, &sema, resolve));
-        })
-        .on::<hir::diagnostics::IncorrectCase, _>(|d| {
-            res.borrow_mut().push(warning_with_fix(d, &sema, resolve));
-        })
-        .on::<hir::diagnostics::ReplaceFilterMapNextWithFindMap, _>(|d| {
-            res.borrow_mut().push(warning_with_fix(d, &sema, resolve));
-        })
-        .on::<hir::diagnostics::InactiveCode, _>(|d| {
-            // If there's inactive code somewhere in a macro, don't propagate to the call-site.
-            if d.display_source().file_id.expansion_info(db).is_some() {
-                return;
-            }
-
-            // Override severity and mark as unused.
-            res.borrow_mut().push(
-                Diagnostic::hint(
-                    sema.diagnostics_display_range(d.display_source()).range,
-                    d.message(),
-                )
-                .with_unused(true)
-                .with_code(Some(d.code())),
-            );
-        })
-        .on::<UnlinkedFile, _>(|d| {
-            // 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 = sema.diagnostics_display_range(d.display_source()).range;
-            let range = range.intersect(TextRange::up_to(TextSize::of("..."))).unwrap_or(range);
-
-            // Override severity and mark as unused.
-            res.borrow_mut().push(
-                Diagnostic::hint(range, d.message())
-                    .with_fixes(d.fixes(&sema, resolve))
-                    .with_code(Some(d.code())),
-            );
-        })
-        .on::<hir::diagnostics::UnresolvedProcMacro, _>(|d| {
-            // Use more accurate position if available.
-            let display_range = d
-                .precise_location
-                .unwrap_or_else(|| sema.diagnostics_display_range(d.display_source()).range);
-
-            // FIXME: it would be nice to tell the user whether proc macros are currently disabled
-            res.borrow_mut()
-                .push(Diagnostic::hint(display_range, d.message()).with_code(Some(d.code())));
-        })
-        .on::<hir::diagnostics::UnresolvedMacroCall, _>(|d| {
-            let last_path_segment = sema.db.parse_or_expand(d.file).and_then(|root| {
-                d.node
-                    .to_node(&root)
-                    .path()
-                    .and_then(|it| it.segment())
-                    .and_then(|it| it.name_ref())
-                    .map(|it| InFile::new(d.file, SyntaxNodePtr::new(it.syntax())))
-            });
-            let diagnostics = last_path_segment.unwrap_or_else(|| d.display_source());
-            let display_range = sema.diagnostics_display_range(diagnostics).range;
-            res.borrow_mut()
-                .push(Diagnostic::error(display_range, d.message()).with_code(Some(d.code())));
-        })
-        .on::<hir::diagnostics::UnimplementedBuiltinMacro, _>(|d| {
-            let display_range = sema.diagnostics_display_range(d.display_source()).range;
-            res.borrow_mut()
-                .push(Diagnostic::hint(display_range, d.message()).with_code(Some(d.code())));
-        })
-        // Only collect experimental diagnostics when they're enabled.
-        .filter(|diag| !(diag.is_experimental() && config.disable_experimental))
-        .filter(|diag| !config.disabled.contains(diag.code().as_str()));
-
-    // Finalize the `DiagnosticSink` building process.
-    let mut sink = sink_builder
-        // Diagnostics not handled above get no fix and default treatment.
-        .build(|d| {
-            res.borrow_mut().push(
-                Diagnostic::error(
-                    sema.diagnostics_display_range(d.display_source()).range,
-                    d.message(),
-                )
-                .with_code(Some(d.code())),
-            );
-        });
-
-    match sema.to_module_def(file_id) {
-        Some(m) => m.diagnostics(db, &mut sink),
-        None => {
-            sink.push(UnlinkedFile { file_id, node: SyntaxNodePtr::new(&parse.tree().syntax()) });
-        }
-    }
-
-    drop(sink);
-    res.into_inner()
-}
-
-fn diagnostic_with_fix<D: DiagnosticWithFixes>(
-    d: &D,
-    sema: &Semantics<RootDatabase>,
-    resolve: &AssistResolveStrategy,
-) -> Diagnostic {
-    Diagnostic::error(sema.diagnostics_display_range(d.display_source()).range, d.message())
-        .with_fixes(d.fixes(&sema, resolve))
-        .with_code(Some(d.code()))
-}
-
-fn warning_with_fix<D: DiagnosticWithFixes>(
-    d: &D,
-    sema: &Semantics<RootDatabase>,
-    resolve: &AssistResolveStrategy,
-) -> Diagnostic {
-    Diagnostic::hint(sema.diagnostics_display_range(d.display_source()).range, d.message())
-        .with_fixes(d.fixes(&sema, resolve))
-        .with_code(Some(d.code()))
-}
-
-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::hint(use_range, "Unnecessary braces in use statement".to_string())
-                .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()
-            .unwrap();
-        let fix = &diagnostic.fixes.unwrap()[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`.
-    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);
-    }
-
-    /// Takes a multi-file input fixture with annotated cursor position and checks that no diagnostics
-    /// apply to the file containing the cursor.
-    pub(crate) fn check_no_diagnostics(ra_fixture: &str) {
-        let (analysis, files) = fixture::files(ra_fixture);
-        let diagnostics = files
-            .into_iter()
-            .flat_map(|file_id| {
-                analysis
-                    .diagnostics(&DiagnosticsConfig::default(), AssistResolveStrategy::All, file_id)
-                    .unwrap()
-            })
-            .collect::<Vec<_>>();
-        assert_eq!(diagnostics.len(), 0, "unexpected diagnostics:\n{:#?}", diagnostics);
-    }
-
-    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)
-    }
-
-    pub(crate) fn check_diagnostics(ra_fixture: &str) {
-        let (analysis, file_id) = fixture::file(ra_fixture);
-        let diagnostics = analysis
-            .diagnostics(&DiagnosticsConfig::default(), AssistResolveStrategy::All, file_id)
-            .unwrap();
-
-        let expected = extract_annotations(&*analysis.file_text(file_id).unwrap());
-        let actual = diagnostics.into_iter().map(|d| (d.range, d.message)).collect::<Vec<_>>();
-        assert_eq!(expected, actual);
-    }
-
-    #[test]
-    fn test_unresolved_macro_range() {
-        check_diagnostics(
-            r#"
-foo::bar!(92);
-   //^^^ unresolved macro `foo::bar!`
-"#,
-        );
-    }
-
-    #[test]
-    fn unresolved_import_in_use_tree() {
-        // Only the relevant part of a nested `use` item should be highlighted.
-        check_diagnostics(
-            r#"
-use does_exist::{Exists, DoesntExist};
-                       //^^^^^^^^^^^ unresolved import
-
-use {does_not_exist::*, does_exist};
-   //^^^^^^^^^^^^^^^^^ unresolved import
-
-use does_not_exist::{
-    a,
-  //^ unresolved import
-    b,
-  //^ unresolved import
-    c,
-  //^ unresolved import
-};
-
-mod does_exist {
-    pub struct Exists;
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn range_mapping_out_of_macros() {
-        // FIXME: this is very wrong, but somewhat tricky to fix.
-        check_fix(
-            r#"
-fn some() {}
-fn items() {}
-fn here() {}
-
-macro_rules! id { ($($tt:tt)*) => { $($tt)*}; }
-
-fn main() {
-    let _x = id![Foo { a: $042 }];
-}
-
-pub struct Foo { pub a: i32, pub b: i32 }
-"#,
-            r#"
-fn some(, b: () ) {}
-fn items() {}
-fn here() {}
-
-macro_rules! id { ($($tt:tt)*) => { $($tt)*}; }
-
-fn main() {
-    let _x = id![Foo { a: 42 }];
-}
-
-pub struct Foo { pub a: i32, pub b: i32 }
-"#,
-        );
-    }
-
-    #[test]
-    fn test_check_unnecessary_braces_in_use_statement() {
-        check_no_diagnostics(
-            r#"
-use a;
-use a::{c, d::e};
-
-mod a {
-    mod c {}
-    mod d {
-        mod e {}
-    }
-}
-"#,
-        );
-        check_no_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 unlinked_file_prepend_first_item() {
-        cov_mark::check!(unlinked_file_prepend_before_first_item);
-        // Only tests the first one for `pub mod` since the rest are the same
-        check_fixes(
-            r#"
-//- /main.rs
-fn f() {}
-//- /foo.rs
-$0
-"#,
-            vec![
-                r#"
-mod foo;
-
-fn f() {}
-"#,
-                r#"
-pub mod foo;
-
-fn f() {}
-"#,
-            ],
-        );
-    }
-
-    #[test]
-    fn unlinked_file_append_mod() {
-        cov_mark::check!(unlinked_file_append_to_existing_mods);
-        check_fix(
-            r#"
-//- /main.rs
-//! Comment on top
-
-mod preexisting;
-
-mod preexisting2;
-
-struct S;
-
-mod preexisting_bottom;)
-//- /foo.rs
-$0
-"#,
-            r#"
-//! Comment on top
-
-mod preexisting;
-
-mod preexisting2;
-mod foo;
-
-struct S;
-
-mod preexisting_bottom;)
-"#,
-        );
-    }
-
-    #[test]
-    fn unlinked_file_insert_in_empty_file() {
-        cov_mark::check!(unlinked_file_empty_file);
-        check_fix(
-            r#"
-//- /main.rs
-//- /foo.rs
-$0
-"#,
-            r#"
-mod foo;
-"#,
-        );
-    }
-
-    #[test]
-    fn unlinked_file_old_style_modrs() {
-        check_fix(
-            r#"
-//- /main.rs
-mod submod;
-//- /submod/mod.rs
-// in mod.rs
-//- /submod/foo.rs
-$0
-"#,
-            r#"
-// in mod.rs
-mod foo;
-"#,
-        );
-    }
-
-    #[test]
-    fn unlinked_file_new_style_mod() {
-        check_fix(
-            r#"
-//- /main.rs
-mod submod;
-//- /submod.rs
-//- /submod/foo.rs
-$0
-"#,
-            r#"
-mod foo;
-"#,
-        );
-    }
-
-    #[test]
-    fn unlinked_file_with_cfg_off() {
-        cov_mark::check!(unlinked_file_skip_fix_when_mod_already_exists);
-        check_no_fix(
-            r#"
-//- /main.rs
-#[cfg(never)]
-mod foo;
-
-//- /foo.rs
-$0
-"#,
-        );
-    }
-
-    #[test]
-    fn unlinked_file_with_cfg_on() {
-        check_no_diagnostics(
-            r#"
-//- /main.rs
-#[cfg(not(never))]
-mod foo;
-
-//- /foo.rs
-"#,
-        );
-    }
-}
diff --git a/crates/ide/src/diagnostics/fixes.rs b/crates/ide/src/diagnostics/fixes.rs
deleted file mode 100644
index 258ac6974..000000000
--- a/crates/ide/src/diagnostics/fixes.rs
+++ /dev/null
@@ -1,31 +0,0 @@
-//! Provides a way to attach fixes to the diagnostics.
-//! The same module also has all curret custom fixes for the diagnostics implemented.
-mod change_case;
-mod create_field;
-mod fill_missing_fields;
-mod remove_semicolon;
-mod replace_with_find_map;
-mod unresolved_module;
-mod wrap_tail_expr;
-
-use hir::{diagnostics::Diagnostic, Semantics};
-use ide_assists::AssistResolveStrategy;
-use ide_db::RootDatabase;
-
-use crate::Assist;
-
-/// A [Diagnostic] that potentially has some fixes available.
-///
-/// [Diagnostic]: hir::diagnostics::Diagnostic
-pub(crate) trait DiagnosticWithFixes: Diagnostic {
-    /// `resolve` determines if the diagnostic should fill in the `edit` field
-    /// of the assist.
-    ///
-    /// If `resolve` is false, the edit will be computed later, on demand, and
-    /// can be omitted.
-    fn fixes(
-        &self,
-        sema: &Semantics<RootDatabase>,
-        _resolve: &AssistResolveStrategy,
-    ) -> Option<Vec<Assist>>;
-}
diff --git a/crates/ide/src/diagnostics/fixes/change_case.rs b/crates/ide/src/diagnostics/fixes/change_case.rs
deleted file mode 100644
index 42be3375f..000000000
--- a/crates/ide/src/diagnostics/fixes/change_case.rs
+++ /dev/null
@@ -1,155 +0,0 @@
-use hir::{db::AstDatabase, diagnostics::IncorrectCase, InFile, Semantics};
-use ide_assists::{Assist, AssistResolveStrategy};
-use ide_db::{base_db::FilePosition, RootDatabase};
-use syntax::AstNode;
-
-use crate::{
-    diagnostics::{unresolved_fix, DiagnosticWithFixes},
-    references::rename::rename_with_semantics,
-};
-
-impl DiagnosticWithFixes for IncorrectCase {
-    fn fixes(
-        &self,
-        sema: &Semantics<RootDatabase>,
-        resolve: &AssistResolveStrategy,
-    ) -> Option<Vec<Assist>> {
-        let root = sema.db.parse_or_expand(self.file)?;
-        let name_node = self.ident.to_node(&root);
-
-        let name_node = InFile::new(self.file, name_node.syntax());
-        let frange = name_node.original_file_range(sema.db);
-        let file_position = FilePosition { file_id: frange.file_id, offset: frange.range.start() };
-
-        let label = format!("Rename to {}", self.suggested_text);
-        let mut res = unresolved_fix("change_case", &label, frange.range);
-        if resolve.should_resolve(&res.id) {
-            let source_change = rename_with_semantics(sema, file_position, &self.suggested_text);
-            res.source_change = Some(source_change.ok().unwrap_or_default());
-        }
-
-        Some(vec![res])
-    }
-}
-
-#[cfg(test)]
-mod change_case {
-    use crate::{
-        diagnostics::tests::{check_fix, check_no_diagnostics},
-        fixture, AssistResolveStrategy, DiagnosticsConfig,
-    };
-
-    #[test]
-    fn test_rename_incorrect_case() {
-        check_fix(
-            r#"
-pub struct test_struct$0 { one: i32 }
-
-pub fn some_fn(val: test_struct) -> test_struct {
-    test_struct { one: val.one + 1 }
-}
-"#,
-            r#"
-pub struct TestStruct { one: i32 }
-
-pub fn some_fn(val: TestStruct) -> TestStruct {
-    TestStruct { one: val.one + 1 }
-}
-"#,
-        );
-
-        check_fix(
-            r#"
-pub fn some_fn(NonSnakeCase$0: u8) -> u8 {
-    NonSnakeCase
-}
-"#,
-            r#"
-pub fn some_fn(non_snake_case: u8) -> u8 {
-    non_snake_case
-}
-"#,
-        );
-
-        check_fix(
-            r#"
-pub fn SomeFn$0(val: u8) -> u8 {
-    if val != 0 { SomeFn(val - 1) } else { val }
-}
-"#,
-            r#"
-pub fn some_fn(val: u8) -> u8 {
-    if val != 0 { some_fn(val - 1) } else { val }
-}
-"#,
-        );
-
-        check_fix(
-            r#"
-fn some_fn() {
-    let whatAWeird_Formatting$0 = 10;
-    another_func(whatAWeird_Formatting);
-}
-"#,
-            r#"
-fn some_fn() {
-    let what_a_weird_formatting = 10;
-    another_func(what_a_weird_formatting);
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn test_uppercase_const_no_diagnostics() {
-        check_no_diagnostics(
-            r#"
-fn foo() {
-    const ANOTHER_ITEM$0: &str = "some_item";
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn test_rename_incorrect_case_struct_method() {
-        check_fix(
-            r#"
-pub struct TestStruct;
-
-impl TestStruct {
-    pub fn SomeFn$0() -> TestStruct {
-        TestStruct
-    }
-}
-"#,
-            r#"
-pub struct TestStruct;
-
-impl TestStruct {
-    pub fn some_fn() -> TestStruct {
-        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);
-    }
-}
diff --git a/crates/ide/src/diagnostics/fixes/fill_missing_fields.rs b/crates/ide/src/diagnostics/fixes/fill_missing_fields.rs
deleted file mode 100644
index b5dd64c08..000000000
--- a/crates/ide/src/diagnostics/fixes/fill_missing_fields.rs
+++ /dev/null
@@ -1,217 +0,0 @@
-use hir::{db::AstDatabase, diagnostics::MissingFields, Semantics};
-use ide_assists::AssistResolveStrategy;
-use ide_db::{source_change::SourceChange, RootDatabase};
-use syntax::{algo, ast::make, AstNode};
-use text_edit::TextEdit;
-
-use crate::{
-    diagnostics::{fix, fixes::DiagnosticWithFixes},
-    Assist,
-};
-
-impl DiagnosticWithFixes for MissingFields {
-    fn fixes(
-        &self,
-        sema: &Semantics<RootDatabase>,
-        _resolve: &AssistResolveStrategy,
-    ) -> Option<Vec<Assist>> {
-        // Note that although we could add a diagnostics to
-        // fill the missing tuple field, e.g :
-        // `struct A(usize);`
-        // `let a = A { 0: () }`
-        // but it is uncommon usage and it should not be encouraged.
-        if self.missed_fields.iter().any(|it| it.as_tuple_index().is_some()) {
-            return None;
-        }
-
-        let root = sema.db.parse_or_expand(self.file)?;
-        let field_list_parent = self.field_list_parent.to_node(&root);
-        let old_field_list = field_list_parent.record_expr_field_list()?;
-        let new_field_list = old_field_list.clone_for_update();
-        for f in self.missed_fields.iter() {
-            let field =
-                make::record_expr_field(make::name_ref(&f.to_string()), Some(make::expr_unit()))
-                    .clone_for_update();
-            new_field_list.add_field(field);
-        }
-
-        let edit = {
-            let mut builder = TextEdit::builder();
-            algo::diff(&old_field_list.syntax(), &new_field_list.syntax())
-                .into_text_edit(&mut builder);
-            builder.finish()
-        };
-        Some(vec![fix(
-            "fill_missing_fields",
-            "Fill struct fields",
-            SourceChange::from_text_edit(self.file.original_file(sema.db), edit),
-            sema.original_range(&field_list_parent.syntax()).range,
-        )])
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use crate::diagnostics::tests::{check_fix, check_no_diagnostics};
-
-    #[test]
-    fn test_fill_struct_fields_empty() {
-        check_fix(
-            r#"
-struct TestStruct { one: i32, two: i64 }
-
-fn test_fn() {
-    let s = TestStruct {$0};
-}
-"#,
-            r#"
-struct TestStruct { one: i32, two: i64 }
-
-fn test_fn() {
-    let s = TestStruct { one: (), two: () };
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn test_fill_struct_fields_self() {
-        check_fix(
-            r#"
-struct TestStruct { one: i32 }
-
-impl TestStruct {
-    fn test_fn() { let s = Self {$0}; }
-}
-"#,
-            r#"
-struct TestStruct { one: i32 }
-
-impl TestStruct {
-    fn test_fn() { let s = Self { one: () }; }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn test_fill_struct_fields_enum() {
-        check_fix(
-            r#"
-enum Expr {
-    Bin { lhs: Box<Expr>, rhs: Box<Expr> }
-}
-
-impl Expr {
-    fn new_bin(lhs: Box<Expr>, rhs: Box<Expr>) -> Expr {
-        Expr::Bin {$0 }
-    }
-}
-"#,
-            r#"
-enum Expr {
-    Bin { lhs: Box<Expr>, rhs: Box<Expr> }
-}
-
-impl Expr {
-    fn new_bin(lhs: Box<Expr>, rhs: Box<Expr>) -> Expr {
-        Expr::Bin { lhs: (), rhs: () }
-    }
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn test_fill_struct_fields_partial() {
-        check_fix(
-            r#"
-struct TestStruct { one: i32, two: i64 }
-
-fn test_fn() {
-    let s = TestStruct{ two: 2$0 };
-}
-"#,
-            r"
-struct TestStruct { one: i32, two: i64 }
-
-fn test_fn() {
-    let s = TestStruct{ two: 2, one: () };
-}
-",
-        );
-    }
-
-    #[test]
-    fn test_fill_struct_fields_raw_ident() {
-        check_fix(
-            r#"
-struct TestStruct { r#type: u8 }
-
-fn test_fn() {
-    TestStruct { $0 };
-}
-"#,
-            r"
-struct TestStruct { r#type: u8 }
-
-fn test_fn() {
-    TestStruct { r#type: ()  };
-}
-",
-        );
-    }
-
-    #[test]
-    fn test_fill_struct_fields_no_diagnostic() {
-        check_no_diagnostics(
-            r#"
-struct TestStruct { one: i32, two: i64 }
-
-fn test_fn() {
-    let one = 1;
-    let s = TestStruct{ one, two: 2 };
-}
-        "#,
-        );
-    }
-
-    #[test]
-    fn test_fill_struct_fields_no_diagnostic_on_spread() {
-        check_no_diagnostics(
-            r#"
-struct TestStruct { one: i32, two: i64 }
-
-fn test_fn() {
-    let one = 1;
-    let s = TestStruct{ ..a };
-}
-"#,
-        );
-    }
-
-    #[test]
-    fn test_fill_struct_fields_blank_line() {
-        check_fix(
-            r#"
-struct S { a: (), b: () }
-
-fn f() {
-    S {
-        $0
-    };
-}
-"#,
-            r#"
-struct S { a: (), b: () }
-
-fn f() {
-    S {
-        a: (),
-        b: (),
-    };
-}
-"#,
-        );
-    }
-}
diff --git a/crates/ide/src/diagnostics/fixes/remove_semicolon.rs b/crates/ide/src/diagnostics/fixes/remove_semicolon.rs
deleted file mode 100644
index f1724d479..000000000
--- a/crates/ide/src/diagnostics/fixes/remove_semicolon.rs
+++ /dev/null
@@ -1,41 +0,0 @@
-use hir::{db::AstDatabase, diagnostics::RemoveThisSemicolon, Semantics};
-use ide_assists::{Assist, AssistResolveStrategy};
-use ide_db::{source_change::SourceChange, RootDatabase};
-use syntax::{ast, AstNode};
-use text_edit::TextEdit;
-
-use crate::diagnostics::{fix, DiagnosticWithFixes};
-
-impl DiagnosticWithFixes for RemoveThisSemicolon {
-    fn fixes(
-        &self,
-        sema: &Semantics<RootDatabase>,
-        _resolve: &AssistResolveStrategy,
-    ) -> Option<Vec<Assist>> {
-        let root = sema.db.parse_or_expand(self.file)?;
-
-        let semicolon = self
-            .expr
-            .to_node(&root)
-            .syntax()
-            .parent()
-            .and_then(ast::ExprStmt::cast)
-            .and_then(|expr| expr.semicolon_token())?
-            .text_range();
-
-        let edit = TextEdit::delete(semicolon);
-        let source_change = SourceChange::from_text_edit(self.file.original_file(sema.db), edit);
-
-        Some(vec![fix("remove_semicolon", "Remove this semicolon", source_change, semicolon)])
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use crate::diagnostics::tests::check_fix;
-
-    #[test]
-    fn remove_semicolon() {
-        check_fix(r#"fn f() -> i32 { 92$0; }"#, r#"fn f() -> i32 { 92 }"#);
-    }
-}
diff --git a/crates/ide/src/diagnostics/fixes/replace_with_find_map.rs b/crates/ide/src/diagnostics/fixes/replace_with_find_map.rs
deleted file mode 100644
index 444bf563b..000000000
--- a/crates/ide/src/diagnostics/fixes/replace_with_find_map.rs
+++ /dev/null
@@ -1,84 +0,0 @@
-use hir::{db::AstDatabase, diagnostics::ReplaceFilterMapNextWithFindMap, Semantics};
-use ide_assists::{Assist, AssistResolveStrategy};
-use ide_db::{source_change::SourceChange, RootDatabase};
-use syntax::{
-    ast::{self, ArgListOwner},
-    AstNode, TextRange,
-};
-use text_edit::TextEdit;
-
-use crate::diagnostics::{fix, DiagnosticWithFixes};
-
-impl DiagnosticWithFixes for ReplaceFilterMapNextWithFindMap {
-    fn fixes(
-        &self,
-        sema: &Semantics<RootDatabase>,
-        _resolve: &AssistResolveStrategy,
-    ) -> Option<Vec<Assist>> {
-        let root = sema.db.parse_or_expand(self.file)?;
-        let next_expr = self.next_expr.to_node(&root);
-        let next_call = ast::MethodCallExpr::cast(next_expr.syntax().clone())?;
-
-        let filter_map_call = ast::MethodCallExpr::cast(next_call.receiver()?.syntax().clone())?;
-        let filter_map_name_range = filter_map_call.name_ref()?.ident_token()?.text_range();
-        let filter_map_args = filter_map_call.arg_list()?;
-
-        let range_to_replace =
-            TextRange::new(filter_map_name_range.start(), next_expr.syntax().text_range().end());
-        let replacement = format!("find_map{}", filter_map_args.syntax().text());
-        let trigger_range = next_expr.syntax().text_range();
-
-        let edit = TextEdit::replace(range_to_replace, replacement);
-
-        let source_change = SourceChange::from_text_edit(self.file.original_file(sema.db), edit);
-
-        Some(vec![fix(
-            "replace_with_find_map",
-            "Replace filter_map(..).next() with find_map()",
-            source_change,
-            trigger_range,
-        )])
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use crate::diagnostics::tests::check_fix;
-
-    #[test]
-    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};
-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 }
-    }
-}
-"#,
-            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 });
-}
-"#,
-        )
-    }
-}
diff --git a/crates/ide/src/diagnostics/unlinked_file.rs b/crates/ide/src/diagnostics/unlinked_file.rs
deleted file mode 100644
index 51fe0f360..000000000
--- a/crates/ide/src/diagnostics/unlinked_file.rs
+++ /dev/null
@@ -1,183 +0,0 @@
-//! Diagnostic emitted for files that aren't part of any crate.
-
-use hir::{
-    db::DefDatabase,
-    diagnostics::{Diagnostic, DiagnosticCode},
-    InFile,
-};
-use ide_assists::AssistResolveStrategy;
-use ide_db::{
-    base_db::{FileId, FileLoader, SourceDatabase, SourceDatabaseExt},
-    source_change::SourceChange,
-    RootDatabase,
-};
-use syntax::{
-    ast::{self, ModuleItemOwner, NameOwner},
-    AstNode, SyntaxNodePtr,
-};
-use text_edit::TextEdit;
-
-use crate::{
-    diagnostics::{fix, fixes::DiagnosticWithFixes},
-    Assist,
-};
-
-// 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.
-#[derive(Debug)]
-pub(crate) struct UnlinkedFile {
-    pub(crate) file_id: FileId,
-    pub(crate) node: SyntaxNodePtr,
-}
-
-impl Diagnostic for UnlinkedFile {
-    fn code(&self) -> DiagnosticCode {
-        DiagnosticCode("unlinked-file")
-    }
-
-    fn message(&self) -> String {
-        "file not included in module tree".to_string()
-    }
-
-    fn display_source(&self) -> InFile<SyntaxNodePtr> {
-        InFile::new(self.file_id.into(), self.node.clone())
-    }
-
-    fn as_any(&self) -> &(dyn std::any::Any + Send + 'static) {
-        self
-    }
-}
-
-impl DiagnosticWithFixes for UnlinkedFile {
-    fn fixes(
-        &self,
-        sema: &hir::Semantics<RootDatabase>,
-        _resolve: &AssistResolveStrategy,
-    ) -> 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 = sema.db.source_root(sema.db.file_source_root(self.file_id));
-        let our_path = source_root.path_for_file(&self.file_id)?;
-        let module_name = our_path.name_and_extension()?.0;
-
-        // Candidates to look for:
-        // - `mod.rs` in the same folder
-        //   - we also check `main.rs` and `lib.rs`
-        // - `$dir.rs` in the parent folder, where `$dir` is the directory containing `self.file_id`
-        let parent = our_path.parent()?;
-        let mut paths =
-            vec![parent.join("mod.rs")?, parent.join("lib.rs")?, parent.join("main.rs")?];
-
-        // `submod/bla.rs` -> `submod.rs`
-        if let Some(newmod) = (|| {
-            let name = parent.name_and_extension()?.0;
-            parent.parent()?.join(&format!("{}.rs", name))
-        })() {
-            paths.push(newmod);
-        }
-
-        for path in &paths {
-            if let Some(parent_id) = source_root.file_for_path(path) {
-                for krate in sema.db.relevant_crates(*parent_id).iter() {
-                    let crate_def_map = sema.db.crate_def_map(*krate);
-                    for (_, module) in crate_def_map.modules() {
-                        if module.origin.is_inline() {
-                            // We don't handle inline `mod parent {}`s, they use different paths.
-                            continue;
-                        }
-
-                        if module.origin.file_id() == Some(*parent_id) {
-                            return make_fixes(sema.db, *parent_id, module_name, self.file_id);
-                        }
-                    }
-                }
-            }
-        }
-
-        None
-    }
-}
-
-fn make_fixes(
-    db: &RootDatabase,
-    parent_file_id: FileId,
-    new_mod_name: &str,
-    added_file_id: FileId,
-) -> Option<Vec<Assist>> {
-    fn is_outline_mod(item: &ast::Item) -> bool {
-        matches!(item, ast::Item::Module(m) if m.item_list().is_none())
-    }
-
-    let mod_decl = format!("mod {};", new_mod_name);
-    let pub_mod_decl = format!("pub mod {};", new_mod_name);
-
-    let ast: ast::SourceFile = db.parse(parent_file_id).tree();
-
-    let mut mod_decl_builder = TextEdit::builder();
-    let mut pub_mod_decl_builder = TextEdit::builder();
-
-    // If there's an existing `mod m;` statement matching the new one, don't emit a fix (it's
-    // probably `#[cfg]`d out).
-    for item in ast.items() {
-        if let ast::Item::Module(m) = item {
-            if let Some(name) = m.name() {
-                if m.item_list().is_none() && name.to_string() == new_mod_name {
-                    cov_mark::hit!(unlinked_file_skip_fix_when_mod_already_exists);
-                    return None;
-                }
-            }
-        }
-    }
-
-    // If there are existing `mod m;` items, append after them (after the first group of them, rather).
-    match ast
-        .items()
-        .skip_while(|item| !is_outline_mod(item))
-        .take_while(|item| is_outline_mod(item))
-        .last()
-    {
-        Some(last) => {
-            cov_mark::hit!(unlinked_file_append_to_existing_mods);
-            let offset = last.syntax().text_range().end();
-            mod_decl_builder.insert(offset, format!("\n{}", mod_decl));
-            pub_mod_decl_builder.insert(offset, format!("\n{}", pub_mod_decl));
-        }
-        None => {
-            // Prepend before the first item in the file.
-            match ast.items().next() {
-                Some(item) => {
-                    cov_mark::hit!(unlinked_file_prepend_before_first_item);
-                    let offset = item.syntax().text_range().start();
-                    mod_decl_builder.insert(offset, format!("{}\n\n", mod_decl));
-                    pub_mod_decl_builder.insert(offset, format!("{}\n\n", pub_mod_decl));
-                }
-                None => {
-                    // No items in the file, so just append at the end.
-                    cov_mark::hit!(unlinked_file_empty_file);
-                    let offset = ast.syntax().text_range().end();
-                    mod_decl_builder.insert(offset, format!("{}\n", mod_decl));
-                    pub_mod_decl_builder.insert(offset, format!("{}\n", pub_mod_decl));
-                }
-            }
-        }
-    }
-
-    let trigger_range = db.parse(added_file_id).tree().syntax().text_range();
-    Some(vec![
-        fix(
-            "add_mod_declaration",
-            &format!("Insert `{}`", mod_decl),
-            SourceChange::from_text_edit(parent_file_id, mod_decl_builder.finish()),
-            trigger_range,
-        ),
-        fix(
-            "add_pub_mod_declaration",
-            &format!("Insert `{}`", pub_mod_decl),
-            SourceChange::from_text_edit(parent_file_id, pub_mod_decl_builder.finish()),
-            trigger_range,
-        ),
-    ])
-}
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 ec3828ab2..7ac0118fe 100644
--- a/crates/ide/src/doc_links.rs
+++ b/crates/ide/src/doc_links.rs
@@ -151,18 +151,18 @@ pub(crate) fn resolve_doc_path_for_def(
 ) -> Option<hir::ModuleDef> {
     match def {
         Definition::ModuleDef(def) => match def {
-            hir::ModuleDef::Module(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::Function(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::Adt(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::Variant(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::Const(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::Static(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::Trait(it) => it.resolve_doc_path(db, &link, ns),
-            hir::ModuleDef::TypeAlias(it) => it.resolve_doc_path(db, &link, ns),
+            hir::ModuleDef::Module(it) => it.resolve_doc_path(db, link, ns),
+            hir::ModuleDef::Function(it) => it.resolve_doc_path(db, link, ns),
+            hir::ModuleDef::Adt(it) => it.resolve_doc_path(db, link, ns),
+            hir::ModuleDef::Variant(it) => it.resolve_doc_path(db, link, ns),
+            hir::ModuleDef::Const(it) => it.resolve_doc_path(db, link, ns),
+            hir::ModuleDef::Static(it) => it.resolve_doc_path(db, link, ns),
+            hir::ModuleDef::Trait(it) => it.resolve_doc_path(db, link, ns),
+            hir::ModuleDef::TypeAlias(it) => it.resolve_doc_path(db, link, ns),
             hir::ModuleDef::BuiltinType(_) => None,
         },
-        Definition::Macro(it) => it.resolve_doc_path(db, &link, ns),
-        Definition::Field(it) => it.resolve_doc_path(db, &link, ns),
+        Definition::Macro(it) => it.resolve_doc_path(db, link, ns),
+        Definition::Field(it) => it.resolve_doc_path(db, link, ns),
         Definition::SelfType(_)
         | Definition::Local(_)
         | Definition::GenericParam(_)
@@ -192,7 +192,7 @@ pub(crate) fn doc_attributes(
             ast::TupleField(it)  => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Field(def))),
             ast::Macro(it)       => sema.to_def(&it).map(|def| (def.attrs(sema.db), Definition::Macro(def))),
             // ast::Use(it) => sema.to_def(&it).map(|def| (Box::new(it) as _, def.attrs(sema.db))),
-            _ => return None
+            _ => None
         }
     }
 }
@@ -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/extend_selection.rs b/crates/ide/src/extend_selection.rs
index 7032889ac..c7ec87edf 100644
--- a/crates/ide/src/extend_selection.rs
+++ b/crates/ide/src/extend_selection.rs
@@ -328,7 +328,7 @@ mod tests {
     use super::*;
 
     fn do_check(before: &str, afters: &[&str]) {
-        let (analysis, position) = fixture::position(&before);
+        let (analysis, position) = fixture::position(before);
         let before = analysis.file_text(position.file_id).unwrap();
         let range = TextRange::empty(position.offset);
         let mut frange = FileRange { file_id: position.file_id, range };
diff --git a/crates/ide/src/fixture.rs b/crates/ide/src/fixture.rs
index 6780af617..cf679edd3 100644
--- a/crates/ide/src/fixture.rs
+++ b/crates/ide/src/fixture.rs
@@ -1,6 +1,5 @@
 //! Utilities for creating `Analysis` instances for tests.
 use ide_db::base_db::fixture::ChangeFixture;
-use syntax::{TextRange, TextSize};
 use test_utils::extract_annotations;
 
 use crate::{Analysis, AnalysisHost, FileId, FilePosition, FileRange};
@@ -13,14 +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();
@@ -63,15 +54,8 @@ pub(crate) fn annotations(ra_fixture: &str) -> (Analysis, FilePosition, Vec<(Fil
 
 pub(crate) fn nav_target_annotation(ra_fixture: &str) -> (Analysis, FilePosition, FileRange) {
     let (analysis, position, mut annotations) = annotations(ra_fixture);
-    let (mut expected, data) = annotations.pop().unwrap();
+    let (expected, data) = annotations.pop().unwrap();
     assert!(annotations.is_empty());
-    match data.as_str() {
-        "" => (),
-        "file" => {
-            expected.range =
-                TextRange::up_to(TextSize::of(&*analysis.file_text(expected.file_id).unwrap()))
-        }
-        data => panic!("bad data: {}", data),
-    }
+    assert_eq!(data, "");
     (analysis, position, expected)
 }
diff --git a/crates/ide/src/goto_definition.rs b/crates/ide/src/goto_definition.rs
index 2d36c34e9..d8e0dc4d5 100644
--- a/crates/ide/src/goto_definition.rs
+++ b/crates/ide/src/goto_definition.rs
@@ -43,7 +43,7 @@ pub(crate) fn goto_definition(
         let (docs, doc_mapping) = attributes.docs_with_rangemap(db)?;
         let (_, link, ns) =
             extract_definitions_from_markdown(docs.as_str()).into_iter().find(|(range, ..)| {
-                doc_mapping.map(range.clone()).map_or(false, |InFile { file_id, value: range }| {
+                doc_mapping.map(*range).map_or(false, |InFile { file_id, value: range }| {
                     file_id == position.file_id.into() && range.contains(position.offset)
                 })
             })?;
@@ -57,7 +57,7 @@ pub(crate) fn goto_definition(
             },
             ast::Name(name) => {
                 let def = NameClass::classify(&sema, &name)?.referenced_or_defined(sema.db);
-                try_find_trait_item_definition(&sema.db, &def)
+                try_find_trait_item_definition(sema.db, &def)
                     .or_else(|| def.try_to_nav(sema.db))
             },
             ast::Lifetime(lt) => if let Some(name_class) = NameClass::classify_lifetime(&sema, &lt) {
@@ -185,7 +185,7 @@ mod tests {
 extern crate std$0;
 //- /std/lib.rs crate:std
 // empty
-//^ file
+//^file
 "#,
         )
     }
@@ -198,7 +198,7 @@ extern crate std$0;
 extern crate std as abc$0;
 //- /std/lib.rs crate:std
 // empty
-//^ file
+//^file
 "#,
         )
     }
@@ -253,7 +253,7 @@ mod $0foo;
 
 //- /foo.rs
 // empty
-//^ file
+//^file
 "#,
         );
 
@@ -264,7 +264,7 @@ mod $0foo;
 
 //- /foo/mod.rs
 // empty
-//^ file
+//^file
 "#,
         );
     }
@@ -395,7 +395,7 @@ use foo as bar$0;
 
 //- /foo/lib.rs crate:foo
 // empty
-//^ file
+//^file
 "#,
         );
     }
@@ -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)>, {}
                        //^^
@@ -1287,7 +1287,7 @@ fn main() {
 }
 //- /foo.txt
 // empty
-//^ file
+//^file
 "#,
         );
     }
diff --git a/crates/ide/src/goto_implementation.rs b/crates/ide/src/goto_implementation.rs
index 95fd39850..0013820b4 100644
--- a/crates/ide/src/goto_implementation.rs
+++ b/crates/ide/src/goto_implementation.rs
@@ -87,7 +87,7 @@ fn impls_for_trait_item(
         .filter_map(|imp| {
             let item = imp.items(sema.db).iter().find_map(|itm| {
                 let itm_name = itm.name(sema.db)?;
-                (itm_name == fun_name).then(|| itm.clone())
+                (itm_name == fun_name).then(|| *itm)
             })?;
             item.try_to_nav(sema.db)
         })
diff --git a/crates/ide/src/goto_type_definition.rs b/crates/ide/src/goto_type_definition.rs
index 004d9cb68..ca3c02bf6 100644
--- a/crates/ide/src/goto_type_definition.rs
+++ b/crates/ide/src/goto_type_definition.rs
@@ -25,7 +25,7 @@ pub(crate) fn goto_type_definition(
     let token: SyntaxToken = pick_best(file.syntax().token_at_offset(position.offset))?;
     let token: SyntaxToken = sema.descend_into_macros(token);
 
-    let (ty, node) = sema.token_ancestors_with_macros(token).find_map(|node| {
+    let (ty, node) = sema.token_ancestors_with_macros(token.clone()).find_map(|node| {
         let ty = match_ast! {
             match node {
                 ast::Expr(it) => sema.type_of_expr(&it)?,
@@ -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 1c6d36939..529cf5f33 100644
--- a/crates/ide/src/hover.rs
+++ b/crates/ide/src/hover.rs
@@ -131,7 +131,7 @@ pub(crate) fn hover(
                     let (docs, doc_mapping) = attributes.docs_with_rangemap(db)?;
                     let (idl_range, link, ns) =
                         extract_definitions_from_markdown(docs.as_str()).into_iter().find_map(|(range, link, ns)| {
-                            let InFile { file_id, value: range } = doc_mapping.map(range.clone())?;
+                            let InFile { file_id, value: range } = doc_mapping.map(range)?;
                             if file_id == position.file_id.into() && range.contains(position.offset) {
                                 Some((range, link, ns))
                             } else {
@@ -288,7 +288,7 @@ fn runnable_action(
 ) -> Option<HoverAction> {
     match def {
         Definition::ModuleDef(it) => match it {
-            ModuleDef::Module(it) => runnable_mod(&sema, it).map(|it| HoverAction::Runnable(it)),
+            ModuleDef::Module(it) => runnable_mod(sema, it).map(HoverAction::Runnable),
             ModuleDef::Function(func) => {
                 let src = func.source(sema.db)?;
                 if src.file_id != file_id.into() {
@@ -297,7 +297,7 @@ fn runnable_action(
                     return None;
                 }
 
-                runnable_fn(&sema, func).map(HoverAction::Runnable)
+                runnable_fn(sema, func).map(HoverAction::Runnable)
             }
             _ => None,
         },
@@ -432,7 +432,7 @@ fn hover_for_definition(
     return match def {
         Definition::Macro(it) => match &it.source(db)?.value {
             Either::Left(mac) => {
-                let label = macro_label(&mac);
+                let label = macro_label(mac);
                 from_def_source_labeled(db, it, Some(label), mod_path)
             }
             Either::Right(_) => {
@@ -516,7 +516,7 @@ fn hover_for_keyword(
     if !token.kind().is_keyword() {
         return None;
     }
-    let famous_defs = FamousDefs(&sema, sema.scope(&token.parent()?).krate());
+    let famous_defs = FamousDefs(sema, sema.scope(&token.parent()?).krate());
     // std exposes {}_keyword modules with docstrings on the root to document keywords
     let keyword_mod = format!("{}_keyword", token.text());
     let doc_owner = find_std_module(&famous_defs, &keyword_mod)?;
@@ -1821,9 +1821,10 @@ 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;
@@ -1845,7 +1846,7 @@ pub struct Bar {
 
                 ---
 
-                [Foo](https://docs.rs/test/*/test/struct.Foo.html)
+                [Foo](struct.Foo.html)
             "#]],
         );
     }
@@ -2999,29 +3000,24 @@ 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: 245..427,
+                                    focus_range: 284..290,
                                     name: "Future",
                                     kind: Trait,
                                     description: "pub trait Future",
diff --git a/crates/ide/src/inlay_hints.rs b/crates/ide/src/inlay_hints.rs
index 821c61403..9cd33d0e4 100644
--- a/crates/ide/src/inlay_hints.rs
+++ b/crates/ide/src/inlay_hints.rs
@@ -96,7 +96,7 @@ fn get_chaining_hints(
     }
 
     let krate = sema.scope(expr.syntax()).module().map(|it| it.krate());
-    let famous_defs = FamousDefs(&sema, krate);
+    let famous_defs = FamousDefs(sema, krate);
 
     let mut tokens = expr
         .syntax()
@@ -165,7 +165,7 @@ fn get_param_name_hints(
             };
             Some((param_name, arg))
         })
-        .filter(|(param_name, arg)| !should_hide_param_name_hint(sema, &callable, param_name, &arg))
+        .filter(|(param_name, arg)| !should_hide_param_name_hint(sema, &callable, param_name, arg))
         .map(|(param_name, arg)| InlayHint {
             range: arg.syntax().text_range(),
             kind: InlayKind::ParameterHint,
@@ -187,7 +187,7 @@ fn get_bind_pat_hints(
     }
 
     let krate = sema.scope(pat.syntax()).module().map(|it| it.krate());
-    let famous_defs = FamousDefs(&sema, krate);
+    let famous_defs = FamousDefs(sema, krate);
 
     let ty = sema.type_of_pat(&pat.clone().into())?;
 
diff --git a/crates/ide/src/join_lines.rs b/crates/ide/src/join_lines.rs
index c67ccd1a9..93d3760bf 100644
--- a/crates/ide/src/join_lines.rs
+++ b/crates/ide/src/join_lines.rs
@@ -60,7 +60,7 @@ fn remove_newlines(edit: &mut TextEditBuilder, token: &SyntaxToken, range: TextR
         let pos: TextSize = (pos as u32).into();
         let offset = token.text_range().start() + range.start() + pos;
         if !edit.invalidates_offset(offset) {
-            remove_newline(edit, &token, offset);
+            remove_newline(edit, token, offset);
         }
     }
 }
diff --git a/crates/ide/src/lib.rs b/crates/ide/src/lib.rs
index 97c9e5d2b..4bd073cc3 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};
@@ -282,20 +283,20 @@ impl Analysis {
         file_id: FileId,
         text_range: Option<TextRange>,
     ) -> Cancellable<String> {
-        self.with_db(|db| syntax_tree::syntax_tree(&db, file_id, text_range))
+        self.with_db(|db| syntax_tree::syntax_tree(db, file_id, text_range))
     }
 
     pub fn view_hir(&self, position: FilePosition) -> Cancellable<String> {
-        self.with_db(|db| view_hir::view_hir(&db, position))
+        self.with_db(|db| view_hir::view_hir(db, position))
     }
 
     pub fn view_item_tree(&self, file_id: FileId) -> Cancellable<String> {
-        self.with_db(|db| view_item_tree::view_item_tree(&db, file_id))
+        self.with_db(|db| view_item_tree::view_item_tree(db, file_id))
     }
 
     /// Renders the crate graph to GraphViz "dot" syntax.
     pub fn view_crate_graph(&self) -> Cancellable<Result<String, String>> {
-        self.with_db(|db| view_crate_graph::view_crate_graph(&db))
+        self.with_db(|db| view_crate_graph::view_crate_graph(db))
     }
 
     pub fn expand_macro(&self, position: FilePosition) -> Cancellable<Option<ExpandedMacro>> {
@@ -315,7 +316,7 @@ impl Analysis {
     /// up minor stuff like continuing the comment.
     /// The edit will be a snippet (with `$0`).
     pub fn on_enter(&self, position: FilePosition) -> Cancellable<Option<TextEdit>> {
-        self.with_db(|db| typing::on_enter(&db, position))
+        self.with_db(|db| typing::on_enter(db, position))
     }
 
     /// Returns an edit which should be applied after a character was typed.
@@ -331,7 +332,7 @@ impl Analysis {
         if !typing::TRIGGER_CHARS.contains(char_typed) {
             return Ok(None);
         }
-        self.with_db(|db| typing::on_char_typed(&db, position, char_typed))
+        self.with_db(|db| typing::on_char_typed(db, position, char_typed))
     }
 
     /// Returns a tree representation of symbols in the file. Useful to draw a
@@ -536,7 +537,7 @@ 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
         })
@@ -549,7 +550,7 @@ 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
@@ -566,9 +567,8 @@ 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())
@@ -576,10 +576,12 @@ 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
         })
@@ -592,14 +594,14 @@ 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(
@@ -607,7 +609,7 @@ 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 f8b64a669..945c9b9e1 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,
@@ -62,7 +60,7 @@ pub(crate) fn find_all_refs(
         if let Some(name) = get_name_of_item_declaration(&syntax, position) {
             (NameClass::classify(sema, &name)?.referenced_or_defined(sema.db), true)
         } else {
-            (find_def(&sema, &syntax, position)?, false)
+            (find_def(sema, &syntax, position)?, false)
         };
 
     let mut usages = def.usages(sema).set_scope(search_scope).include_self_refs().all();
diff --git a/crates/ide/src/references/rename.rs b/crates/ide/src/rename.rs
index 7dfc5043e..8096dfa0e 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 syntax::{ast, AstNode, SyntaxNode};
 
 use text_edit::TextEdit;
 
-use crate::{display::TryToNav, FilePosition, FileSystemEdit, RangeInfo, SourceChange, TextRange};
-
-type RenameResult<T> = Result<T, RenameError>;
-#[derive(Debug)]
-pub struct RenameError(String);
-
-impl fmt::Display for RenameError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        Display::fmt(&self.0, f)
-    }
-}
+use crate::{FilePosition, RangeInfo, SourceChange};
 
-macro_rules! format_err {
-    ($fmt:expr) => {RenameError(format!($fmt))};
-    ($fmt:expr, $($arg:tt)+) => {RenameError(format!($fmt, $($arg)+))}
-}
+pub use ide_db::rename::RenameError;
 
-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.
@@ -52,26 +32,10 @@ pub(crate) fn prepare_rename(
     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)
+    let frange = def
+        .range_for_rename(&sema)
         .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, ()))
+    Ok(RangeInfo::new(frange.range, ()))
 }
 
 // Feature: Rename
@@ -103,12 +67,19 @@ pub(crate) fn rename_with_semantics(
     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),
+
+    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.
@@ -119,38 +90,12 @@ 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,
@@ -192,145 +137,6 @@ fn find_definition(
     .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(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)
-}
-
 fn rename_to_self(sema: &Semantics<RootDatabase>, local: hir::Local) -> RenameResult<SourceChange> {
     if never!(local.is_self(sema.db)) {
         bail!("rename_to_self invoked on self");
@@ -398,8 +204,15 @@ 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"))?;
 
@@ -413,7 +226,7 @@ fn rename_self_to_param(
     let mut source_change = SourceChange::default();
     source_change.insert_source_edit(file_id.original_file(sema.db), edit);
     source_change.extend(usages.iter().map(|(&file_id, references)| {
-        (file_id, source_edit_from_references(&references, def, new_name))
+        (file_id, source_edit_from_references(references, def, new_name))
     }));
     Ok(source_change)
 }
@@ -426,7 +239,7 @@ fn text_edit_from_self_param(self_param: &ast::SelfParam, new_name: &str) -> Opt
         None
     }
 
-    let impl_def = self_param.syntax().ancestors().find_map(|it| ast::Impl::cast(it))?;
+    let impl_def = self_param.syntax().ancestors().find_map(ast::Impl::cast)?;
     let type_name = target_type_name(&impl_def)?;
 
     let mut replacement_text = String::from(new_name);
@@ -441,150 +254,6 @@ 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};
@@ -659,7 +328,7 @@ mod tests {
     fn test_prepare_rename_namelikes() {
         check_prepare(r"fn name$0<'lifetime>() {}", expect![[r#"3..7: name"#]]);
         check_prepare(r"fn name<'lifetime$0>() {}", expect![[r#"8..17: 'lifetime"#]]);
-        check_prepare(r"fn name<'lifetime>() { name$0(); }", expect![[r#"23..27: name"#]]);
+        check_prepare(r"fn name<'lifetime>() { name$0(); }", expect![[r#"3..7: name"#]]);
     }
 
     #[test]
@@ -691,7 +360,7 @@ fn baz() {
     x.0$0 = 5;
 }
 "#,
-            expect![[r#"No identifier available to rename"#]],
+            expect![[r#"No references found at position"#]],
         );
     }
 
@@ -703,7 +372,7 @@ fn foo() {
     let x: i32$0 = 0;
 }
 "#,
-            expect![[r#"Cannot rename builtin type"#]],
+            expect![[r#"No references found at position"#]],
         );
     }
 
@@ -719,7 +388,7 @@ impl Foo {
     }
 }
 "#,
-            expect![[r#"Cannot rename `Self`"#]],
+            expect![[r#"No references found at position"#]],
         );
     }
 
@@ -801,7 +470,6 @@ impl Foo {
 
     #[test]
     fn test_rename_for_local() {
-        cov_mark::check!(rename_local);
         check(
             "k",
             r#"
@@ -2101,4 +1769,22 @@ 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/runnables.rs b/crates/ide/src/runnables.rs
index 552054951..03faabadc 100644
--- a/crates/ide/src/runnables.rs
+++ b/crates/ide/src/runnables.rs
@@ -158,7 +158,7 @@ fn find_related_tests(
     search_scope: Option<SearchScope>,
     tests: &mut FxHashSet<Runnable>,
 ) {
-    if let Some(refs) = references::find_all_refs(&sema, position, search_scope) {
+    if let Some(refs) = references::find_all_refs(sema, position, search_scope) {
         for (file_id, refs) in refs.references {
             let file = sema.parse(file_id);
             let file = file.syntax();
@@ -169,10 +169,10 @@ fn find_related_tests(
             });
 
             for fn_def in functions {
-                if let Some(runnable) = as_test_runnable(&sema, &fn_def) {
+                if let Some(runnable) = as_test_runnable(sema, &fn_def) {
                     // direct test
                     tests.insert(runnable);
-                } else if let Some(module) = parent_test_module(&sema, &fn_def) {
+                } else if let Some(module) = parent_test_module(sema, &fn_def) {
                     // indirect test
                     find_related_tests_in_module(sema, &fn_def, &module, tests);
                 }
@@ -203,7 +203,7 @@ fn find_related_tests_in_module(
 }
 
 fn as_test_runnable(sema: &Semantics<RootDatabase>, fn_def: &ast::Fn) -> Option<Runnable> {
-    if test_related_attribute(&fn_def).is_some() {
+    if test_related_attribute(fn_def).is_some() {
         let function = sema.to_def(fn_def)?;
         runnable_fn(sema, function)
     } else {
diff --git a/crates/ide/src/syntax_highlighting.rs b/crates/ide/src/syntax_highlighting.rs
index b03f1c71f..e186b82b7 100644
--- a/crates/ide/src/syntax_highlighting.rs
+++ b/crates/ide/src/syntax_highlighting.rs
@@ -323,7 +323,7 @@ fn traverse(
         if let Some(token) = element.as_token().cloned().and_then(ast::String::cast) {
             if token.is_raw() {
                 let expanded = element_to_highlight.as_token().unwrap().clone();
-                if inject::ra_fixture(hl, &sema, token, expanded).is_some() {
+                if inject::ra_fixture(hl, sema, token, expanded).is_some() {
                     continue;
                 }
             }
@@ -334,7 +334,7 @@ fn traverse(
         }
 
         if let Some((mut highlight, binding_hash)) = highlight::element(
-            &sema,
+            sema,
             krate,
             &mut bindings_shadow_count,
             syntactic_name_ref_highlighting,
diff --git a/crates/ide/src/syntax_highlighting/highlight.rs b/crates/ide/src/syntax_highlighting/highlight.rs
index 9503c936d..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
@@ -131,6 +151,9 @@ pub(super) fn element(
         }
         STRING | BYTE_STRING => HlTag::StringLiteral.into(),
         ATTR => HlTag::Attribute.into(),
+        INT_NUMBER if element.ancestors().nth(1).map_or(false, |it| it.kind() == FIELD_EXPR) => {
+            SymbolKind::Field.into()
+        }
         INT_NUMBER | FLOAT_NUMBER => HlTag::NumericLiteral.into(),
         BYTE => HlTag::ByteLiteral.into(),
         CHAR => HlTag::CharLiteral.into(),
@@ -351,15 +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));
 
@@ -446,12 +461,12 @@ fn highlight_method_call(
     krate: Option<hir::Crate>,
     method_call: &ast::MethodCallExpr,
 ) -> Option<Highlight> {
-    let func = sema.resolve_method_call(&method_call)?;
+    let func = sema.resolve_method_call(method_call)?;
 
     let mut h = SymbolKind::Function.into();
     h |= HlMod::Associated;
 
-    if func.is_unsafe(sema.db) || sema.is_unsafe_method_call(&method_call) {
+    if func.is_unsafe(sema.db) || sema.is_unsafe_method_call(method_call) {
         h |= HlMod::Unsafe;
     }
     if func.is_async(sema.db) {
@@ -523,11 +538,9 @@ fn highlight_name_ref_by_syntax(
     };
 
     match parent.kind() {
-        METHOD_CALL_EXPR => {
-            return ast::MethodCallExpr::cast(parent)
-                .and_then(|it| highlight_method_call(sema, krate, &it))
-                .unwrap_or_else(|| SymbolKind::Function.into());
-        }
+        METHOD_CALL_EXPR => ast::MethodCallExpr::cast(parent)
+            .and_then(|it| highlight_method_call(sema, krate, &it))
+            .unwrap_or_else(|| SymbolKind::Function.into()),
         FIELD_EXPR => {
             let h = HlTag::Symbol(SymbolKind::Field);
             let is_union = ast::FieldExpr::cast(parent)
diff --git a/crates/ide/src/syntax_highlighting/html.rs b/crates/ide/src/syntax_highlighting/html.rs
index 5327af845..21376a7ae 100644
--- a/crates/ide/src/syntax_highlighting/html.rs
+++ b/crates/ide/src/syntax_highlighting/html.rs
@@ -23,7 +23,7 @@ pub(crate) fn highlight_as_html(db: &RootDatabase, file_id: FileId, rainbow: boo
     let hl_ranges = highlight(db, file_id, None, false);
     let text = parse.tree().syntax().to_string();
     let mut buf = String::new();
-    buf.push_str(&STYLE);
+    buf.push_str(STYLE);
     buf.push_str("<pre><code>");
     for r in &hl_ranges {
         let chunk = html_escape(&text[r.range]);
@@ -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/inject.rs b/crates/ide/src/syntax_highlighting/inject.rs
index 4269d339e..ec43c8579 100644
--- a/crates/ide/src/syntax_highlighting/inject.rs
+++ b/crates/ide/src/syntax_highlighting/inject.rs
@@ -23,7 +23,7 @@ pub(super) fn ra_fixture(
     literal: ast::String,
     expanded: SyntaxToken,
 ) -> Option<()> {
-    let active_parameter = ActiveParameter::at_token(&sema, expanded)?;
+    let active_parameter = ActiveParameter::at_token(sema, expanded)?;
     if !active_parameter.ident().map_or(false, |name| name.text().starts_with("ra_fixture")) {
         return None;
     }
@@ -124,7 +124,7 @@ pub(super) fn doc_comment(
     }
 
     for attr in attributes.by_key("doc").attrs() {
-        let InFile { file_id, value: src } = attrs_source_map.source_of(&attr);
+        let InFile { file_id, value: src } = attrs_source_map.source_of(attr);
         if file_id != node.file_id {
             continue;
         }
@@ -232,7 +232,7 @@ fn find_doc_string_in_attr(attr: &hir::Attr, it: &ast::Attr) -> Option<ast::Stri
                     string.text().get(1..string.text().len() - 1).map_or(false, |it| it == text)
                 })
         }
-        _ => return None,
+        _ => None,
     }
 }
 
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 a7b5c3b89..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; }
@@ -215,8 +216,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
     <span class="keyword">let</span> <span class="variable callable declaration">a</span> <span class="operator">=</span> <span class="punctuation">|</span><span class="value_param declaration">x</span><span class="punctuation">|</span> <span class="value_param">x</span><span class="semicolon">;</span>
     <span class="keyword">let</span> <span class="variable callable declaration">bar</span> <span class="operator">=</span> <span class="struct">Foo</span><span class="operator">::</span><span class="function associated">baz</span><span class="semicolon">;</span>
 
-    <span class="keyword">let</span> <span class="variable declaration">baz</span> <span class="operator">=</span> <span class="numeric_literal">-</span><span class="numeric_literal">42</span><span class="semicolon">;</span>
-    <span class="keyword">let</span> <span class="variable declaration">baz</span> <span class="operator">=</span> <span class="operator">-</span><span class="variable">baz</span><span class="semicolon">;</span>
+    <span class="keyword">let</span> <span class="variable declaration">baz</span> <span class="operator">=</span> <span class="parenthesis">(</span><span class="numeric_literal">-</span><span class="numeric_literal">42</span><span class="comma">,</span><span class="parenthesis">)</span><span class="semicolon">;</span>
+    <span class="keyword">let</span> <span class="variable declaration">baz</span> <span class="operator">=</span> <span class="operator">-</span><span class="variable">baz</span><span class="operator">.</span><span class="field">0</span><span class="semicolon">;</span>
 
     <span class="keyword">let</span> <span class="punctuation">_</span> <span class="operator">=</span> <span class="logical">!</span><span class="bool_literal">true</span><span class="semicolon">;</span>
 
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 6ad2a362a..4f0b1ce85 100644
--- a/crates/ide/src/syntax_highlighting/tests.rs
+++ b/crates/ide/src/syntax_highlighting/tests.rs
@@ -189,8 +189,8 @@ fn main() {
     let a = |x| x;
     let bar = Foo::baz;
 
-    let baz = -42;
-    let baz = -baz;
+    let baz = (-42,);
+    let baz = -baz.0;
 
     let _ = !true;
 
@@ -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/on_enter.rs b/crates/ide/src/typing/on_enter.rs
index 81c4d95b1..5cba9d11d 100644
--- a/crates/ide/src/typing/on_enter.rs
+++ b/crates/ide/src/typing/on_enter.rs
@@ -88,12 +88,12 @@ fn on_enter_in_comment(
         if comment.text().ends_with(' ') {
             cov_mark::hit!(continues_end_of_line_comment_with_space);
             remove_trailing_whitespace = true;
-        } else if !followed_by_comment(&comment) {
+        } else if !followed_by_comment(comment) {
             return None;
         }
     }
 
-    let indent = node_indent(&file, comment.syntax())?;
+    let indent = node_indent(file, comment.syntax())?;
     let inserted = format!("\n{}{} $0", indent, prefix);
     let delete = if remove_trailing_whitespace {
         let trimmed_len = comment.text().trim_end().len() as u32;
@@ -188,7 +188,7 @@ mod tests {
     use crate::fixture;
 
     fn apply_on_enter(before: &str) -> Option<String> {
-        let (analysis, position) = fixture::position(&before);
+        let (analysis, position) = fixture::position(before);
         let result = analysis.on_enter(position).unwrap()?;
 
         let mut actual = analysis.file_text(position.file_id).unwrap().to_string();
diff --git a/crates/ide_assists/Cargo.toml b/crates/ide_assists/Cargo.toml
index a83acb191..0d0d1605e 100644
--- a/crates/ide_assists/Cargo.toml
+++ b/crates/ide_assists/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = { version = "1.1", features = ["thread-local"] }
+cov-mark = "2.0.0-pre.1"
 rustc-hash = "1.1.0"
 itertools = "0.10.0"
 either = "1.6.1"
diff --git a/crates/ide_assists/src/assist_context.rs b/crates/ide_assists/src/assist_context.rs
index 8fc40f9bd..36a2bf89a 100644
--- a/crates/ide_assists/src/assist_context.rs
+++ b/crates/ide_assists/src/assist_context.rs
@@ -291,8 +291,7 @@ impl AssistBuilder {
         algo::diff(old.syntax(), new.syntax()).into_text_edit(&mut self.edit)
     }
     pub(crate) fn create_file(&mut self, dst: AnchoredPathBuf, content: impl Into<String>) {
-        let file_system_edit =
-            FileSystemEdit::CreateFile { dst: dst, initial_contents: content.into() };
+        let file_system_edit = FileSystemEdit::CreateFile { dst, initial_contents: content.into() };
         self.source_change.push_file_system_edit(file_system_edit);
     }
 
diff --git a/crates/ide_assists/src/handlers/apply_demorgan.rs b/crates/ide_assists/src/handlers/apply_demorgan.rs
index 5c936a510..c93959e66 100644
--- a/crates/ide_assists/src/handlers/apply_demorgan.rs
+++ b/crates/ide_assists/src/handlers/apply_demorgan.rs
@@ -78,12 +78,12 @@ pub(crate) fn apply_demorgan(acc: &mut Assists, ctx: &AssistContext) -> Option<(
             terms.sort_by_key(|t| t.syntax().text_range().start());
             let mut terms = VecDeque::from(terms);
 
-            let paren_expr = expr.syntax().parent().and_then(|parent| ast::ParenExpr::cast(parent));
+            let paren_expr = expr.syntax().parent().and_then(ast::ParenExpr::cast);
 
             let neg_expr = paren_expr
                 .clone()
                 .and_then(|paren_expr| paren_expr.syntax().parent())
-                .and_then(|parent| ast::PrefixExpr::cast(parent))
+                .and_then(ast::PrefixExpr::cast)
                 .and_then(|prefix_expr| {
                     if prefix_expr.op_kind().unwrap() == ast::PrefixOp::Not {
                         Some(prefix_expr)
diff --git a/crates/ide_assists/src/handlers/convert_comment_block.rs b/crates/ide_assists/src/handlers/convert_comment_block.rs
index d202a85f9..749e8685b 100644
--- a/crates/ide_assists/src/handlers/convert_comment_block.rs
+++ b/crates/ide_assists/src/handlers/convert_comment_block.rs
@@ -88,7 +88,7 @@ fn line_to_block(acc: &mut Assists, comment: ast::Comment) -> Option<()> {
             // We pick a single indentation level for the whole block comment based on the
             // comment where the assist was invoked. This will be prepended to the
             // contents of each line comment when they're put into the block comment.
-            let indentation = IndentLevel::from_token(&comment.syntax());
+            let indentation = IndentLevel::from_token(comment.syntax());
 
             let block_comment_body =
                 comments.into_iter().map(|c| line_comment_text(indentation, c)).join("\n");
@@ -167,7 +167,7 @@ fn line_comment_text(indentation: IndentLevel, comm: ast::Comment) -> String {
     if contents.is_empty() {
         contents.to_owned()
     } else {
-        indentation.to_string() + &contents
+        indentation.to_string() + contents
     }
 }
 
diff --git a/crates/ide_assists/src/handlers/early_return.rs b/crates/ide_assists/src/handlers/early_return.rs
index 5eb6a57f0..ef4a7cb50 100644
--- a/crates/ide_assists/src/handlers/early_return.rs
+++ b/crates/ide_assists/src/handlers/early_return.rs
@@ -108,7 +108,7 @@ pub(crate) fn convert_to_guarded_return(acc: &mut Assists, ctx: &AssistContext)
         "Convert to guarded return",
         target,
         |edit| {
-            let if_indent_level = IndentLevel::from_node(&if_expr.syntax());
+            let if_indent_level = IndentLevel::from_node(if_expr.syntax());
             let new_block = match if_let_pat {
                 None => {
                     // If.
@@ -174,7 +174,7 @@ pub(crate) fn convert_to_guarded_return(acc: &mut Assists, ctx: &AssistContext)
                         .take_while(|i| *i != end_of_then),
                 );
                 replace_children(
-                    &parent_block.syntax(),
+                    parent_block.syntax(),
                     RangeInclusive::new(
                         if_expr.clone().syntax().clone().into(),
                         if_expr.syntax().clone().into(),
diff --git a/crates/ide_assists/src/handlers/extract_function.rs b/crates/ide_assists/src/handlers/extract_function.rs
index a2dba915c..f2be091f4 100644
--- a/crates/ide_assists/src/handlers/extract_function.rs
+++ b/crates/ide_assists/src/handlers/extract_function.rs
@@ -76,7 +76,7 @@ pub(crate) fn extract_function(acc: &mut Assists, ctx: &AssistContext) -> Option
     let module = ctx.sema.scope(&insert_after).module()?;
 
     let vars_defined_in_body_and_outlive =
-        vars_defined_in_body_and_outlive(ctx, &body, &node.parent().as_ref().unwrap_or(&node));
+        vars_defined_in_body_and_outlive(ctx, &body, node.parent().as_ref().unwrap_or(&node));
     let ret_ty = body_return_ty(ctx, &body)?;
 
     // FIXME: we compute variables that outlive here just to check `never!` condition
@@ -782,7 +782,7 @@ fn expr_require_exclusive_access(ctx: &AssistContext, expr: &ast::Expr) -> Optio
     Some(false)
 }
 
-/// Container of local varaible usages
+/// Container of local variable usages
 ///
 /// Semanticall same as `UsageSearchResult`, but provides more convenient interface
 struct LocalUsages(ide_db::search::UsageSearchResult);
@@ -808,7 +808,7 @@ trait HasTokenAtOffset {
 
 impl HasTokenAtOffset for SyntaxNode {
     fn token_at_offset(&self, offset: TextSize) -> TokenAtOffset<SyntaxToken> {
-        SyntaxNode::token_at_offset(&self, offset)
+        SyntaxNode::token_at_offset(self, offset)
     }
 }
 
@@ -854,7 +854,7 @@ fn vars_defined_in_body_and_outlive(
     body: &FunctionBody,
     parent: &SyntaxNode,
 ) -> Vec<OutlivedLocal> {
-    let vars_defined_in_body = vars_defined_in_body(&body, ctx);
+    let vars_defined_in_body = vars_defined_in_body(body, ctx);
     vars_defined_in_body
         .into_iter()
         .filter_map(|var| var_outlives_body(ctx, body, var, parent))
@@ -868,7 +868,7 @@ fn is_defined_before(
     src: &hir::InFile<Either<ast::IdentPat, ast::SelfParam>>,
 ) -> bool {
     src.file_id.original_file(ctx.db()) == ctx.frange.file_id
-        && !body.contains_node(&either_syntax(&src.value))
+        && !body.contains_node(either_syntax(&src.value))
 }
 
 fn either_syntax(value: &Either<ast::IdentPat, ast::SelfParam>) -> &SyntaxNode {
diff --git a/crates/ide_assists/src/handlers/fill_match_arms.rs b/crates/ide_assists/src/handlers/fill_match_arms.rs
index 3d2cd739a..5a43bdd6f 100644
--- a/crates/ide_assists/src/handlers/fill_match_arms.rs
+++ b/crates/ide_assists/src/handlers/fill_match_arms.rs
@@ -202,7 +202,7 @@ impl ExtendedEnum {
     fn variants(self, db: &RootDatabase) -> Vec<ExtendedVariant> {
         match self {
             ExtendedEnum::Enum(e) => {
-                e.variants(db).into_iter().map(|x| ExtendedVariant::Variant(x)).collect::<Vec<_>>()
+                e.variants(db).into_iter().map(ExtendedVariant::Variant).collect::<Vec<_>>()
             }
             ExtendedEnum::Bool => {
                 Vec::<ExtendedVariant>::from([ExtendedVariant::True, ExtendedVariant::False])
@@ -212,7 +212,7 @@ impl ExtendedEnum {
 }
 
 fn resolve_enum_def(sema: &Semantics<RootDatabase>, expr: &ast::Expr) -> Option<ExtendedEnum> {
-    sema.type_of_expr(&expr)?.autoderef(sema.db).find_map(|ty| match ty.as_adt() {
+    sema.type_of_expr(expr)?.autoderef(sema.db).find_map(|ty| match ty.as_adt() {
         Some(Adt::Enum(e)) => Some(ExtendedEnum::Enum(e)),
         _ => {
             if ty.is_bool() {
@@ -228,7 +228,7 @@ fn resolve_tuple_of_enum_def(
     sema: &Semantics<RootDatabase>,
     expr: &ast::Expr,
 ) -> Option<Vec<ExtendedEnum>> {
-    sema.type_of_expr(&expr)?
+    sema.type_of_expr(expr)?
         .tuple_fields(sema.db)
         .iter()
         .map(|ty| {
diff --git a/crates/ide_assists/src/handlers/fix_visibility.rs b/crates/ide_assists/src/handlers/fix_visibility.rs
index 89f7b2c2c..f834bf16a 100644
--- a/crates/ide_assists/src/handlers/fix_visibility.rs
+++ b/crates/ide_assists/src/handlers/fix_visibility.rs
@@ -43,7 +43,7 @@ fn add_vis_to_referenced_module_def(acc: &mut Assists, ctx: &AssistContext) -> O
         _ => return None,
     };
 
-    let current_module = ctx.sema.scope(&path.syntax()).module()?;
+    let current_module = ctx.sema.scope(path.syntax()).module()?;
     let target_module = def.module(ctx.db())?;
 
     let vis = target_module.visibility_of(ctx.db(), &def)?;
@@ -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_enum_is_method.rs b/crates/ide_assists/src/handlers/generate_enum_is_method.rs
index a9f71a703..24939f262 100644
--- a/crates/ide_assists/src/handlers/generate_enum_is_method.rs
+++ b/crates/ide_assists/src/handlers/generate_enum_is_method.rs
@@ -47,7 +47,7 @@ pub(crate) fn generate_enum_is_method(acc: &mut Assists, ctx: &AssistContext) ->
     let fn_name = format!("is_{}", &to_lower_snake_case(&variant_name.text()));
 
     // Return early if we've found an existing new fn
-    let impl_def = find_struct_impl(&ctx, &parent_enum, &fn_name)?;
+    let impl_def = find_struct_impl(ctx, &parent_enum, &fn_name)?;
 
     let target = variant.syntax().text_range();
     acc.add(
diff --git a/crates/ide_assists/src/handlers/generate_enum_projection_method.rs b/crates/ide_assists/src/handlers/generate_enum_projection_method.rs
index e2f572ba3..986fb2315 100644
--- a/crates/ide_assists/src/handlers/generate_enum_projection_method.rs
+++ b/crates/ide_assists/src/handlers/generate_enum_projection_method.rs
@@ -136,7 +136,7 @@ fn generate_enum_projection_method(
         format!("{}_{}", props.fn_name_prefix, &to_lower_snake_case(&variant_name.text()));
 
     // Return early if we've found an existing new fn
-    let impl_def = find_struct_impl(&ctx, &parent_enum, &fn_name)?;
+    let impl_def = find_struct_impl(ctx, &parent_enum, &fn_name)?;
 
     let target = variant.syntax().text_range();
     acc.add(AssistId(assist_id, AssistKind::Generate), assist_description, target, |builder| {
diff --git a/crates/ide_assists/src/handlers/generate_function.rs b/crates/ide_assists/src/handlers/generate_function.rs
index bc9fc524b..6a658d4cf 100644
--- a/crates/ide_assists/src/handlers/generate_function.rs
+++ b/crates/ide_assists/src/handlers/generate_function.rs
@@ -59,7 +59,7 @@ pub(crate) fn generate_function(acc: &mut Assists, ctx: &AssistContext) -> Optio
         None => None,
     };
 
-    let function_builder = FunctionBuilder::from_call(&ctx, &call, &path, target_module)?;
+    let function_builder = FunctionBuilder::from_call(ctx, &call, &path, target_module)?;
 
     let target = call.syntax().text_range();
     acc.add(
@@ -128,12 +128,12 @@ impl FunctionBuilder {
                 file = in_file;
                 target
             }
-            None => next_space_for_fn_after_call_site(&call)?,
+            None => next_space_for_fn_after_call_site(call)?,
         };
         let needs_pub = target_module.is_some();
         let target_module = target_module.or_else(|| ctx.sema.scope(target.syntax()).module())?;
-        let fn_name = fn_name(&path)?;
-        let (type_params, params) = fn_args(ctx, target_module, &call)?;
+        let fn_name = fn_name(path)?;
+        let (type_params, params) = fn_args(ctx, target_module, call)?;
 
         // should_render_snippet intends to express a rough level of confidence about
         // the correctness of the return type.
@@ -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/generate_getter.rs b/crates/ide_assists/src/handlers/generate_getter.rs
index 09971226e..cc020c92c 100644
--- a/crates/ide_assists/src/handlers/generate_getter.rs
+++ b/crates/ide_assists/src/handlers/generate_getter.rs
@@ -75,7 +75,7 @@ pub(crate) fn generate_getter_impl(
     if mutable {
         format_to!(fn_name, "_mut");
     }
-    let impl_def = find_struct_impl(&ctx, &ast::Adt::Struct(strukt.clone()), fn_name.as_str())?;
+    let impl_def = find_struct_impl(ctx, &ast::Adt::Struct(strukt.clone()), fn_name.as_str())?;
 
     let (id, label) = if mutable {
         ("generate_getter_mut", "Generate a mut getter method")
diff --git a/crates/ide_assists/src/handlers/generate_new.rs b/crates/ide_assists/src/handlers/generate_new.rs
index 959a1f86c..b65e8387b 100644
--- a/crates/ide_assists/src/handlers/generate_new.rs
+++ b/crates/ide_assists/src/handlers/generate_new.rs
@@ -36,7 +36,7 @@ pub(crate) fn generate_new(acc: &mut Assists, ctx: &AssistContext) -> Option<()>
     };
 
     // Return early if we've found an existing new fn
-    let impl_def = find_struct_impl(&ctx, &ast::Adt::Struct(strukt.clone()), "new")?;
+    let impl_def = find_struct_impl(ctx, &ast::Adt::Struct(strukt.clone()), "new")?;
 
     let target = strukt.syntax().text_range();
     acc.add(AssistId("generate_new", AssistKind::Generate), "Generate `new`", target, |builder| {
diff --git a/crates/ide_assists/src/handlers/generate_setter.rs b/crates/ide_assists/src/handlers/generate_setter.rs
index 288cf745d..5bdf6b3f4 100644
--- a/crates/ide_assists/src/handlers/generate_setter.rs
+++ b/crates/ide_assists/src/handlers/generate_setter.rs
@@ -39,7 +39,7 @@ pub(crate) fn generate_setter(acc: &mut Assists, ctx: &AssistContext) -> Option<
     // Return early if we've found an existing fn
     let fn_name = to_lower_snake_case(&field_name.to_string());
     let impl_def = find_struct_impl(
-        &ctx,
+        ctx,
         &ast::Adt::Struct(strukt.clone()),
         format!("set_{}", fn_name).as_str(),
     )?;
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 c8226550f..b20fe992d 100644
--- a/crates/ide_assists/src/handlers/remove_dbg.rs
+++ b/crates/ide_assists/src/handlers/remove_dbg.rs
@@ -85,7 +85,7 @@ fn whitespace_start(it: SyntaxElement) -> Option<TextSize> {
 }
 
 fn adjusted_macro_contents(macro_call: &ast::MacroCall) -> Option<String> {
-    let contents = get_valid_macrocall_contents(&macro_call, "dbg")?;
+    let contents = get_valid_macrocall_contents(macro_call, "dbg")?;
     let macro_text_with_brackets = macro_call.token_tree()?.syntax().text();
     let macro_text_in_brackets = macro_text_with_brackets.slice(TextRange::new(
         TextSize::of('('),
diff --git a/crates/ide_assists/src/handlers/reorder_fields.rs b/crates/ide_assists/src/handlers/reorder_fields.rs
index 933acead1..f6a926042 100644
--- a/crates/ide_assists/src/handlers/reorder_fields.rs
+++ b/crates/ide_assists/src/handlers/reorder_fields.rs
@@ -28,7 +28,7 @@ pub(crate) fn reorder_fields(acc: &mut Assists, ctx: &AssistContext) -> Option<(
         .or_else(|| ctx.find_node_at_offset::<ast::RecordPat>().map(Either::Right))?;
 
     let path = record.as_ref().either(|it| it.path(), |it| it.path())?;
-    let ranks = compute_fields_ranks(&path, &ctx)?;
+    let ranks = compute_fields_ranks(&path, ctx)?;
     let get_rank_of_field =
         |of: Option<_>| *ranks.get(&of.unwrap_or_default()).unwrap_or(&usize::MAX);
 
diff --git a/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs b/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs
index 10d9cec31..f9474c9f5 100644
--- a/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs
+++ b/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs
@@ -112,7 +112,7 @@ fn add_assist(
             let insert_pos = adt.syntax().text_range().end();
             let impl_def_with_items =
                 impl_def_from_trait(&ctx.sema, &annotated_name, trait_, trait_path);
-            update_attribute(builder, &input, &trait_name, &attr);
+            update_attribute(builder, input, &trait_name, attr);
             let trait_path = format!("{}", trait_path);
             match (ctx.config.snippet_cap, impl_def_with_items) {
                 (None, _) => {
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 aee880625..9404aa26d 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
@@ -169,7 +169,7 @@ pub(crate) fn replace_match_with_if_let(acc: &mut Assists, ctx: &AssistContext)
 }
 
 fn is_pat_wildcard_or_sad(sema: &hir::Semantics<RootDatabase>, pat: &ast::Pat) -> bool {
-    sema.type_of_pat(&pat)
+    sema.type_of_pat(pat)
         .and_then(|ty| TryEnum::from_ty(sema, &ty))
         .map(|it| it.sad_pattern().syntax().text() == pat.syntax().text())
         .unwrap_or_else(|| matches!(pat, ast::Pat::WildcardPat(_)))
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/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/handlers/wrap_return_type_in_result.rs b/crates/ide_assists/src/handlers/wrap_return_type_in_result.rs
index 2f1da82c7..140e27356 100644
--- a/crates/ide_assists/src/handlers/wrap_return_type_in_result.rs
+++ b/crates/ide_assists/src/handlers/wrap_return_type_in_result.rs
@@ -123,7 +123,7 @@ impl TailReturnCollector {
     fn handle_exprs(&mut self, expr: &Expr, collect_break: bool) {
         match expr {
             Expr::BlockExpr(block_expr) => {
-                self.collect_jump_exprs(&block_expr, collect_break);
+                self.collect_jump_exprs(block_expr, collect_break);
             }
             Expr::ReturnExpr(ret_expr) => {
                 if let Some(ret_expr_arg) = &ret_expr.expr() {
diff --git a/crates/ide_assists/src/lib.rs b/crates/ide_assists/src/lib.rs
index 16af72927..fa378a622 100644
--- a/crates/ide_assists/src/lib.rs
+++ b/crates/ide_assists/src/lib.rs
@@ -17,156 +17,31 @@ 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 => return true,
-            AssistKind::Refactor => match other {
-                AssistKind::RefactorExtract
-                | AssistKind::RefactorInline
-                | AssistKind::RefactorRewrite => return true,
-                _ => return false,
-            },
-            _ => return 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 2b7c2d581..60cecd94c 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 {
@@ -74,18 +74,18 @@ pub(crate) fn check_assist_unresolved(assist: Handler, ra_fixture: &str) {
 #[track_caller]
 fn check_doc_test(assist_id: &str, before: &str, after: &str) {
     let after = trim_indent(after);
-    let (db, file_id, selection) = RootDatabase::with_range_or_offset(&before);
+    let (db, file_id, selection) = RootDatabase::with_range_or_offset(before);
     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<_>>()
@@ -210,7 +210,7 @@ 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 +235,7 @@ 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 +264,7 @@ 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 +279,7 @@ 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 +292,7 @@ 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 +317,7 @@ 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 +353,7 @@ pub fn test_some_range(a: int) -> bool {
     }
 
     {
-        let assists = Assist::get(
+        let assists = assists(
             &db,
             &cfg,
             AssistResolveStrategy::Single(SingleResolve {
@@ -397,7 +397,7 @@ pub fn test_some_range(a: int) -> bool {
     }
 
     {
-        let assists = Assist::get(
+        let assists = assists(
             &db,
             &cfg,
             AssistResolveStrategy::Single(SingleResolve {
@@ -462,7 +462,7 @@ 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/utils.rs b/crates/ide_assists/src/utils.rs
index 30128a24a..068df005b 100644
--- a/crates/ide_assists/src/utils.rs
+++ b/crates/ide_assists/src/utils.rs
@@ -492,7 +492,7 @@ pub(crate) fn add_method_to_adt(
     let start_offset = impl_def
         .and_then(|impl_def| find_impl_block_end(impl_def, &mut buf))
         .unwrap_or_else(|| {
-            buf = generate_impl_text(&adt, &buf);
+            buf = generate_impl_text(adt, &buf);
             adt.syntax().text_range().end()
         });
 
diff --git a/crates/ide_assists/src/utils/suggest_name.rs b/crates/ide_assists/src/utils/suggest_name.rs
index b3aabeab3..cb8bc8b2f 100644
--- a/crates/ide_assists/src/utils/suggest_name.rs
+++ b/crates/ide_assists/src/utils/suggest_name.rs
@@ -187,7 +187,7 @@ fn from_method_call(expr: &ast::Expr) -> Option<String> {
         }
     }
 
-    normalize(&name)
+    normalize(name)
 }
 
 fn from_param(expr: &ast::Expr, sema: &Semantics<'_, RootDatabase>) -> Option<String> {
diff --git a/crates/ide_completion/Cargo.toml b/crates/ide_completion/Cargo.toml
index ba81c9e04..3c45fe1cb 100644
--- a/crates/ide_completion/Cargo.toml
+++ b/crates/ide_completion/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = { version = "1.1", features = ["thread-local"] }
+cov-mark = "2.0.0-pre.1"
 itertools = "0.10.0"
 log = "0.4.8"
 rustc-hash = "1.1.0"
diff --git a/crates/ide_completion/src/completions.rs b/crates/ide_completion/src/completions.rs
index fbd499900..783305005 100644
--- a/crates/ide_completion/src/completions.rs
+++ b/crates/ide_completion/src/completions.rs
@@ -29,7 +29,7 @@ use crate::{
         macro_::render_macro,
         pattern::{render_struct_pat, render_variant_pat},
         render_field, render_resolution, render_tuple_field,
-        type_alias::render_type_alias,
+        type_alias::{render_type_alias, render_type_alias_with_eq},
         RenderContext,
     },
     CompletionContext, CompletionItem, CompletionItemKind,
@@ -109,9 +109,6 @@ impl Completions {
         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 +131,6 @@ 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));
     }
 
@@ -178,9 +172,6 @@ impl Completions {
     }
 
     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));
     }
 
@@ -188,6 +179,14 @@ impl Completions {
         self.add_opt(render_type_alias(RenderContext::new(ctx), type_alias));
     }
 
+    pub(crate) fn add_type_alias_with_eq(
+        &mut self,
+        ctx: &CompletionContext,
+        type_alias: hir::TypeAlias,
+    ) {
+        self.add_opt(render_type_alias_with_eq(RenderContext::new(ctx), type_alias));
+    }
+
     pub(crate) fn add_qualified_enum_variant(
         &mut self,
         ctx: &CompletionContext,
@@ -204,32 +203,30 @@ impl Completions {
         variant: hir::Variant,
         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);
     }
 }
 
+/// Calls the callback for each variant of the provided enum with the path to the variant.
 fn complete_enum_variants(
     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 7f76e357e..6df569c2a 100644
--- a/crates/ide_completion/src/completions/attribute.rs
+++ b/crates/ide_completion/src/completions/attribute.rs
@@ -219,7 +219,7 @@ static KIND_TO_ATTRIBUTES: Lazy<FxHashMap<SyntaxKind, &[&str]>> = Lazy::new(|| {
 });
 const EXPR_ATTRIBUTES: &[&str] = attrs!();
 
-/// https://doc.rust-lang.org/reference/attributes.html#built-in-attributes-index
+/// <https://doc.rust-lang.org/reference/attributes.html#built-in-attributes-index>
 // Keep these sorted for the binary search!
 const ATTRIBUTES: &[AttrCompletion] = &[
     attr("allow(…)", Some("allow"), Some("allow(${0:lint})")),
diff --git a/crates/ide_completion/src/completions/attribute/derive.rs b/crates/ide_completion/src/completions/attribute/derive.rs
index d526824fb..7b3133e53 100644
--- a/crates/ide_completion/src/completions/attribute/derive.rs
+++ b/crates/ide_completion/src/completions/attribute/derive.rs
@@ -93,57 +93,20 @@ 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
-            "#]],
-        );
+        // FIXME: Add build-in derives to fixture.
+        check(r#"#[derive($0)] struct Test;"#, expect![[r#""#]]);
     }
 
     #[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 Clone, Copy
-                at Debug
-                at Default
-                at Hash
-                at Eq
-                at PartialOrd
-                at Eq, PartialOrd, Ord
-            "#]],
-        )
+        // FIXME: Add build-in derives to fixture.
+        check(r#"#[derive(serde::Serialize, PartialEq, $0)] struct Test;"#, expect![[r#""#]])
     }
 
     #[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 Clone, Copy
-                at Debug
-                at Default
-                at Hash
-                at Eq
-                at PartialOrd
-                at Eq, PartialOrd, Ord
-            "#]],
-        )
+        // FIXME: Add build-in derives to fixture.
+        check(r#"#[derive($0 serde::Serialize, PartialEq)] struct Test;"#, expect![[r#""#]])
     }
 }
diff --git a/crates/ide_completion/src/completions/dot.rs b/crates/ide_completion/src/completions/dot.rs
index 8ad57a069..9552875c1 100644
--- a/crates/ide_completion/src/completions/dot.rs
+++ b/crates/ide_completion/src/completions/dot.rs
@@ -13,7 +13,7 @@ pub(crate) fn complete_dot(acc: &mut Completions, ctx: &CompletionContext) {
         _ => return complete_undotted_self(acc, ctx),
     };
 
-    let receiver_ty = match ctx.sema.type_of_expr(&dot_receiver) {
+    let receiver_ty = match ctx.sema.type_of_expr(dot_receiver) {
         Some(ty) => ty,
         _ => return,
     };
diff --git a/crates/ide_completion/src/completions/flyimport.rs b/crates/ide_completion/src/completions/flyimport.rs
index c010cbbca..30b8d44bd 100644
--- a/crates/ide_completion/src/completions/flyimport.rs
+++ b/crates/ide_completion/src/completions/flyimport.rs
@@ -1,10 +1,10 @@
 //! Feature: completion with imports-on-the-fly
 //!
 //! When completing names in the current scope, proposes additional imports from other modules or crates,
-//! if they can be qualified in the scope and their name contains all symbols from the completion input.
+//! if they can be qualified in the scope, and their name contains all symbols from the completion input.
 //!
 //! To be considered applicable, the name must contain all input symbols in the given order, not necessarily adjacent.
-//! If any input symbol is not lowercased, the name must contain all symbols in exact case; otherwise the contaning is checked case-insensitively.
+//! If any input symbol is not lowercased, the name must contain all symbols in exact case; otherwise the containing is checked case-insensitively.
 //!
 //! ```
 //! fn main() {
@@ -23,8 +23,8 @@
 //! ```
 //!
 //! Also completes associated items, that require trait imports.
-//! If any unresolved and/or partially-qualified path predeces the input, it will be taken into account.
-//! Currently, only the imports with their import path ending with the whole qialifier will be proposed
+//! If any unresolved and/or partially-qualified path precedes the input, it will be taken into account.
+//! Currently, only the imports with their import path ending with the whole qualifier will be proposed
 //! (no fuzzy matching for qualifier).
 //!
 //! ```
@@ -61,14 +61,14 @@
 //! }
 //! ```
 //!
-//! NOTE: currently, if an assoc item comes from a trait that's not currently imported and it also has an unresolved and/or partially-qualified path,
+//! NOTE: currently, if an assoc item comes from a trait that's not currently imported, and it also has an unresolved and/or partially-qualified path,
 //! no imports will be proposed.
 //!
 //! .Fuzzy search details
 //!
 //! To avoid an excessive amount of the results returned, completion input is checked for inclusion in the names only
 //! (i.e. in `HashMap` in the `std::collections::HashMap` path).
-//! For the same reasons, avoids searching for any path imports for inputs with their length less that 2 symbols
+//! For the same reasons, avoids searching for any path imports for inputs with their length less than 2 symbols
 //! (but shows all associated items for any input length).
 //!
 //! .Import configuration
@@ -79,15 +79,15 @@
 //! .LSP and performance implications
 //!
 //! The feature is enabled only if the LSP client supports LSP protocol version 3.16+ and reports the `additionalTextEdits`
-//! (case sensitive) resolve client capability in its client capabilities.
+//! (case-sensitive) resolve client capability in its client capabilities.
 //! This way the server is able to defer the costly computations, doing them for a selected completion item only.
 //! For clients with no such support, all edits have to be calculated on the completion request, including the fuzzy search completion ones,
 //! which might be slow ergo the feature is automatically disabled.
 //!
 //! .Feature toggle
 //!
-//! The feature can be forcefully turned off in the settings with the `rust-analyzer.completion.enableAutoimportCompletions` flag.
-//! Note that having this flag set to `true` does not guarantee that the feature is enabled: your client needs to have the corredponding
+//! The feature can be forcefully turned off in the settings with the `rust-analyzer.completion.autoimport.enable` flag.
+//! Note that having this flag set to `true` does not guarantee that the feature is enabled: your client needs to have the corresponding
 //! capability enabled.
 
 use ide_db::helpers::{
diff --git a/crates/ide_completion/src/completions/keyword.rs b/crates/ide_completion/src/completions/keyword.rs
index ba13d3707..0fccbeccf 100644
--- a/crates/ide_completion/src/completions/keyword.rs
+++ b/crates/ide_completion/src/completions/keyword.rs
@@ -536,17 +536,11 @@ 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 +549,12 @@ 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
diff --git a/crates/ide_completion/src/completions/postfix.rs b/crates/ide_completion/src/completions/postfix.rs
index 86eb21714..9f98b21be 100644
--- a/crates/ide_completion/src/completions/postfix.rs
+++ b/crates/ide_completion/src/completions/postfix.rs
@@ -34,7 +34,7 @@ pub(crate) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
 
     let receiver_text = get_receiver_text(dot_receiver, receiver_is_ambiguous_float_literal);
 
-    let receiver_ty = match ctx.sema.type_of_expr(&dot_receiver) {
+    let receiver_ty = match ctx.sema.type_of_expr(dot_receiver) {
         Some(it) => it,
         None => return,
     };
@@ -50,7 +50,7 @@ pub(crate) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
                 postfix_snippet(
                     ctx,
                     cap,
-                    &dot_receiver,
+                    dot_receiver,
                     "ifl",
                     "if let Ok {}",
                     &format!("if let Ok($1) = {} {{\n    $0\n}}", receiver_text),
@@ -60,7 +60,7 @@ pub(crate) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
                 postfix_snippet(
                     ctx,
                     cap,
-                    &dot_receiver,
+                    dot_receiver,
                     "while",
                     "while let Ok {}",
                     &format!("while let Ok($1) = {} {{\n    $0\n}}", receiver_text),
@@ -71,7 +71,7 @@ pub(crate) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
                 postfix_snippet(
                     ctx,
                     cap,
-                    &dot_receiver,
+                    dot_receiver,
                     "ifl",
                     "if let Some {}",
                     &format!("if let Some($1) = {} {{\n    $0\n}}", receiver_text),
@@ -81,7 +81,7 @@ pub(crate) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
                 postfix_snippet(
                     ctx,
                     cap,
-                    &dot_receiver,
+                    dot_receiver,
                     "while",
                     "while let Some {}",
                     &format!("while let Some($1) = {} {{\n    $0\n}}", receiver_text),
@@ -93,7 +93,7 @@ pub(crate) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
         postfix_snippet(
             ctx,
             cap,
-            &dot_receiver,
+            dot_receiver,
             "if",
             "if expr {}",
             &format!("if {} {{\n    $0\n}}", receiver_text),
@@ -102,22 +102,22 @@ pub(crate) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
         postfix_snippet(
             ctx,
             cap,
-            &dot_receiver,
+            dot_receiver,
             "while",
             "while expr {}",
             &format!("while {} {{\n    $0\n}}", receiver_text),
         )
         .add_to(acc);
-        postfix_snippet(ctx, cap, &dot_receiver, "not", "!expr", &format!("!{}", receiver_text))
+        postfix_snippet(ctx, cap, dot_receiver, "not", "!expr", &format!("!{}", receiver_text))
             .add_to(acc);
     }
 
-    postfix_snippet(ctx, cap, &dot_receiver, "ref", "&expr", &format!("&{}", receiver_text))
+    postfix_snippet(ctx, cap, dot_receiver, "ref", "&expr", &format!("&{}", receiver_text))
         .add_to(acc);
     postfix_snippet(
         ctx,
         cap,
-        &dot_receiver,
+        dot_receiver,
         "refm",
         "&mut expr",
         &format!("&mut {}", receiver_text),
diff --git a/crates/ide_completion/src/completions/postfix/format_like.rs b/crates/ide_completion/src/completions/postfix/format_like.rs
index 9ebe1dcc0..2dc13c293 100644
--- a/crates/ide_completion/src/completions/postfix/format_like.rs
+++ b/crates/ide_completion/src/completions/postfix/format_like.rs
@@ -53,7 +53,7 @@ pub(crate) fn add_format_like_completions(
         for (label, macro_name) in KINDS {
             let snippet = parser.into_suggestion(macro_name);
 
-            postfix_snippet(ctx, cap, &dot_receiver, label, macro_name, &snippet).add_to(acc);
+            postfix_snippet(ctx, cap, dot_receiver, label, macro_name, &snippet).add_to(acc);
         }
     }
 }
@@ -91,7 +91,7 @@ enum State {
 impl FormatStrParser {
     pub(crate) fn new(input: String) -> Self {
         Self {
-            input: input,
+            input,
             output: String::new(),
             extracted_expressions: Vec::new(),
             state: State::NotExpr,
diff --git a/crates/ide_completion/src/completions/qualified_path.rs b/crates/ide_completion/src/completions/qualified_path.rs
index 58d4dd9ee..1643eeed4 100644
--- a/crates/ide_completion/src/completions/qualified_path.rs
+++ b/crates/ide_completion/src/completions/qualified_path.rs
@@ -15,10 +15,11 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
         None => return,
     };
 
-    let resolution = match ctx.sema.resolve_path(&path) {
+    let resolution = match ctx.sema.resolve_path(path) {
         Some(res) => res,
         None => return,
     };
+
     let context_module = ctx.scope.module();
 
     if ctx.expects_item() || ctx.expects_assoc_item() {
@@ -60,21 +61,31 @@ 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::ScopeDef::ModuleDef(hir::ModuleDef::Variant(_))
+                    | hir::ScopeDef::ModuleDef(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(_)) => {
             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 +93,7 @@ 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 +118,7 @@ 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 +140,7 @@ 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 +152,7 @@ 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 +165,7 @@ 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::<()>
                 });
@@ -176,10 +175,22 @@ 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)]
@@ -927,4 +938,24 @@ fn main() {
             "#]],
         );
     }
+
+    #[test]
+    fn completes_types_and_const_in_arg_list() {
+        check(
+            r#"
+mod foo {
+    pub const CONST: () = ();
+    pub type Type = ();
+}
+
+struct Foo<T>(t);
+
+fn foo(_: Foo<foo::$0>) {}
+"#,
+            expect![[r#"
+                ta Type
+                ct CONST
+            "#]],
+        );
+    }
 }
diff --git a/crates/ide_completion/src/completions/unqualified_path.rs b/crates/ide_completion/src/completions/unqualified_path.rs
index b1e6b2b77..b5af1c810 100644
--- a/crates/ide_completion/src/completions/unqualified_path.rs
+++ b/crates/ide_completion/src/completions/unqualified_path.rs
@@ -1,8 +1,9 @@
 //! Completion of names from the current scope, e.g. locals and imported items.
 
 use hir::ScopeDef;
+use syntax::{ast, AstNode};
 
-use crate::{CompletionContext, Completions};
+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() {
@@ -35,21 +36,50 @@ 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::complete_enum_variants(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 {
+        if let Some(path_seg) = arg_list.syntax().parent().and_then(ast::PathSegment::cast) {
+            if let Some(hir::PathResolution::Def(hir::ModuleDef::Trait(trait_))) =
+                ctx.sema.resolve_path(&path_seg.parent_path())
+            {
+                trait_.items(ctx.sema.db).into_iter().for_each(|it| {
+                    if let hir::AssocItem::TypeAlias(alias) = it {
+                        acc.add_type_alias_with_eq(ctx, alias)
+                    }
+                });
+            }
+        }
     }
 
     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 {
+            // Don't suggest attribute macros and derives.
             ScopeDef::MacroDef(mac) => mac.is_fn_like(),
+            // no values in type places
+            ScopeDef::ModuleDef(hir::ModuleDef::Function(_))
+            | ScopeDef::ModuleDef(hir::ModuleDef::Variant(_))
+            | ScopeDef::ModuleDef(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 {
@@ -777,4 +807,30 @@ $0
             "#]],
         )
     }
+
+    #[test]
+    fn completes_types_and_const_in_arg_list() {
+        check(
+            r#"
+enum Bar {
+    Baz
+}
+trait Foo {
+    type Bar;
+}
+
+const CONST: () = ();
+
+fn foo<T: Foo<$0>, const CONST_PARAM: usize>(_: T) {}
+"#,
+            expect![[r#"
+                ta Bar =       type Bar;
+                tp T
+                cp CONST_PARAM
+                tt Foo
+                en Bar
+                ct CONST
+            "#]],
+        );
+    }
 }
diff --git a/crates/ide_completion/src/context.rs b/crates/ide_completion/src/context.rs
index 2c2a4aa6b..a8437d81c 100644
--- a/crates/ide_completion/src/context.rs
+++ b/crates/ide_completion/src/context.rs
@@ -276,6 +276,10 @@ 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))
     }
@@ -380,7 +384,7 @@ impl<'a> CompletionContext<'a> {
                         (|| {
                             let expr_field = self.token.prev_sibling_or_token()?
                                       .into_node()
-                                      .and_then(|node| ast::RecordExprField::cast(node))?;
+                                      .and_then(ast::RecordExprField::cast)?;
                             let (_, _, ty) = self.sema.resolve_record_field(&expr_field)?;
                             Some((
                                 Some(ty),
@@ -467,7 +471,7 @@ impl<'a> CompletionContext<'a> {
         self.expected_type = expected_type;
         self.expected_name = expected_name;
 
-        let name_like = match find_node_at_offset(&&file_with_fake_ident, offset) {
+        let name_like = match find_node_at_offset(&file_with_fake_ident, offset) {
             Some(it) => it,
             None => return,
         };
diff --git a/crates/ide_completion/src/patterns.rs b/crates/ide_completion/src/patterns.rs
index ee87bf461..72e67e3c4 100644
--- a/crates/ide_completion/src/patterns.rs
+++ b/crates/ide_completion/src/patterns.rs
@@ -47,6 +47,9 @@ pub(crate) enum ImmediateLocation {
         receiver_is_ambiguous_float_literal: bool,
     },
     // Original file ast node
+    // Only set from a type arg
+    GenericArgList(ast::GenericArgList),
+    // Original file ast node
     /// The record expr of the field name we are completing
     RecordExpr(ast::RecordExpr),
     // Original file ast node
@@ -112,12 +115,12 @@ pub(crate) fn determine_location(
 ) -> Option<ImmediateLocation> {
     let node = match name_like {
         ast::NameLike::NameRef(name_ref) => {
-            if ast::RecordExprField::for_field_name(&name_ref).is_some() {
+            if ast::RecordExprField::for_field_name(name_ref).is_some() {
                 return sema
                     .find_node_at_offset_with_macros(original_file, offset)
                     .map(ImmediateLocation::RecordExpr);
             }
-            if ast::RecordPatField::for_field_name_ref(&name_ref).is_some() {
+            if ast::RecordPatField::for_field_name_ref(name_ref).is_some() {
                 return sema
                     .find_node_at_offset_with_macros(original_file, offset)
                     .map(ImmediateLocation::RecordPat);
@@ -125,7 +128,7 @@ pub(crate) fn determine_location(
             maximize_name_ref(name_ref)
         }
         ast::NameLike::Name(name) => {
-            if ast::RecordPatField::for_field_name(&name).is_some() {
+            if ast::RecordPatField::for_field_name(name).is_some() {
                 return sema
                     .find_node_at_offset_with_macros(original_file, offset)
                     .map(ImmediateLocation::RecordPat);
@@ -159,7 +162,6 @@ pub(crate) fn determine_location(
             }
         }
     };
-
     let res = match_ast! {
         match parent {
             ast::IdentPat(_it) => ImmediateLocation::IdentPat,
@@ -174,6 +176,9 @@ pub(crate) fn determine_location(
                 Some(TRAIT) => ImmediateLocation::Trait,
                 _ => return None,
             },
+            ast::GenericArgList(_it) => sema
+                .find_node_at_offset_with_macros(original_file, offset)
+                .map(ImmediateLocation::GenericArgList)?,
             ast::Module(it) => {
                 if it.item_list().is_none() {
                     ImmediateLocation::ModDeclaration(it)
@@ -254,7 +259,7 @@ fn test_inside_impl_trait_block() {
 }
 
 pub(crate) fn previous_token(element: SyntaxElement) -> Option<SyntaxToken> {
-    element.into_token().and_then(|it| previous_non_trivia_token(it))
+    element.into_token().and_then(previous_non_trivia_token)
 }
 
 /// Check if the token previous to the previous one is `for`.
@@ -262,8 +267,8 @@ pub(crate) fn previous_token(element: SyntaxElement) -> Option<SyntaxToken> {
 pub(crate) fn for_is_prev2(element: SyntaxElement) -> bool {
     element
         .into_token()
-        .and_then(|it| previous_non_trivia_token(it))
-        .and_then(|it| previous_non_trivia_token(it))
+        .and_then(previous_non_trivia_token)
+        .and_then(previous_non_trivia_token)
         .filter(|it| it.kind() == T![for])
         .is_some()
 }
diff --git a/crates/ide_completion/src/render.rs b/crates/ide_completion/src/render.rs
index d3db55c35..2bd2c44d0 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> {
@@ -86,7 +39,7 @@ impl<'a> RenderContext<'a> {
     }
 
     fn db(&self) -> &'a RootDatabase {
-        &self.completion.db
+        self.completion.db
     }
 
     fn source_range(&self) -> TextRange {
@@ -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,
@@ -1007,6 +980,7 @@ fn go(world: &WorldSnapshot) { go(w$0) }
 
     #[test]
     fn too_many_arguments() {
+        cov_mark::check!(too_many_arguments);
         check_relevance(
             r#"
 struct Foo;
@@ -1151,16 +1125,11 @@ fn main() {
     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 {
@@ -1184,8 +1153,9 @@ fn main() {
                 st T []
                 st S []
                 fn main() []
-                tt Deref []
                 fn foo(…) []
+                md core []
+                tt Sized []
             "#]],
         )
     }
@@ -1194,21 +1164,11 @@ 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 {
@@ -1216,7 +1176,7 @@ 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
     }
@@ -1235,12 +1195,12 @@ 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 []
             "#]],
         )
     }
diff --git a/crates/ide_completion/src/render/macro_.rs b/crates/ide_completion/src/render/macro_.rs
index 429d937c8..3a7238bb8 100644
--- a/crates/ide_completion/src/render/macro_.rs
+++ b/crates/ide_completion/src/render/macro_.rs
@@ -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/render/pattern.rs b/crates/ide_completion/src/render/pattern.rs
index b4e80f424..3717a0409 100644
--- a/crates/ide_completion/src/render/pattern.rs
+++ b/crates/ide_completion/src/render/pattern.rs
@@ -75,10 +75,10 @@ fn render_pat(
 ) -> Option<String> {
     let mut pat = match kind {
         StructKind::Tuple if ctx.snippet_cap().is_some() => {
-            render_tuple_as_pat(&fields, &name, fields_omitted)
+            render_tuple_as_pat(fields, name, fields_omitted)
         }
         StructKind::Record => {
-            render_record_as_pat(ctx.db(), ctx.snippet_cap(), &fields, &name, fields_omitted)
+            render_record_as_pat(ctx.db(), ctx.snippet_cap(), fields, name, fields_omitted)
         }
         _ => return None,
     };
@@ -86,7 +86,7 @@ fn render_pat(
     if ctx.completion.is_param {
         pat.push(':');
         pat.push(' ');
-        pat.push_str(&name);
+        pat.push_str(name);
     }
     if ctx.snippet_cap().is_some() {
         pat.push_str("$0");
diff --git a/crates/ide_completion/src/render/type_alias.rs b/crates/ide_completion/src/render/type_alias.rs
index e47b4c745..e0234171a 100644
--- a/crates/ide_completion/src/render/type_alias.rs
+++ b/crates/ide_completion/src/render/type_alias.rs
@@ -16,7 +16,14 @@ pub(crate) fn render_type_alias<'a>(
     ctx: RenderContext<'a>,
     type_alias: hir::TypeAlias,
 ) -> Option<CompletionItem> {
-    TypeAliasRender::new(ctx, type_alias)?.render()
+    TypeAliasRender::new(ctx, type_alias)?.render(false)
+}
+
+pub(crate) fn render_type_alias_with_eq<'a>(
+    ctx: RenderContext<'a>,
+    type_alias: hir::TypeAlias,
+) -> Option<CompletionItem> {
+    TypeAliasRender::new(ctx, type_alias)?.render(true)
 }
 
 #[derive(Debug)]
@@ -32,8 +39,14 @@ impl<'a> TypeAliasRender<'a> {
         Some(TypeAliasRender { ctx, type_alias, ast_node })
     }
 
-    fn render(self) -> Option<CompletionItem> {
-        let name = self.name()?;
+    fn render(self, with_eq: bool) -> Option<CompletionItem> {
+        let name = self.ast_node.name().map(|name| {
+            if with_eq {
+                format!("{} = ", name.text())
+            } else {
+                name.text().to_string()
+            }
+        })?;
         let detail = self.detail();
 
         let mut item =
@@ -49,10 +62,6 @@ impl<'a> TypeAliasRender<'a> {
         Some(item.build())
     }
 
-    fn name(&self) -> Option<String> {
-        self.ast_node.name().map(|name| name.text().to_string())
-    }
-
     fn detail(&self) -> String {
         type_label(&self.ast_node)
     }
diff --git a/crates/ide_db/Cargo.toml b/crates/ide_db/Cargo.toml
index 6229996ec..e219c577a 100644
--- a/crates/ide_db/Cargo.toml
+++ b/crates/ide_db/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = { version = "1.1", features = ["thread-local"] }
+cov-mark = "2.0.0-pre.1"
 log = "0.4.8"
 rayon = "1.5.0"
 fst = { version = "0.4", default-features = false }
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/call_info.rs b/crates/ide_db/src/call_info.rs
index 933bcad55..4795e2565 100644
--- a/crates/ide_db/src/call_info.rs
+++ b/crates/ide_db/src/call_info.rs
@@ -162,7 +162,7 @@ impl ActiveParameter {
     }
 
     pub fn at_token(sema: &Semantics<RootDatabase>, token: SyntaxToken) -> Option<Self> {
-        let (signature, active_parameter) = call_info_impl(&sema, token)?;
+        let (signature, active_parameter) = call_info_impl(sema, token)?;
 
         let idx = active_parameter?;
         let mut params = signature.params(sema.db);
diff --git a/crates/ide_db/src/helpers/import_assets.rs b/crates/ide_db/src/helpers/import_assets.rs
index ae52dd8bb..9634d872e 100644
--- a/crates/ide_db/src/helpers/import_assets.rs
+++ b/crates/ide_db/src/helpers/import_assets.rs
@@ -323,7 +323,7 @@ fn import_for_item(
     }
 
     let segment_import =
-        find_import_for_segment(db, original_item_candidate, &unresolved_first_segment)?;
+        find_import_for_segment(db, original_item_candidate, unresolved_first_segment)?;
     let trait_item_to_import = item_as_assoc(db, original_item)
         .and_then(|assoc| assoc.containing_trait(db))
         .map(|trait_| ItemInNs::from(ModuleDef::from(trait_)));
@@ -383,7 +383,7 @@ fn find_import_for_segment(
         original_item
     } else {
         let matching_module =
-            module_with_segment_name(db, &unresolved_first_segment, original_item)?;
+            module_with_segment_name(db, unresolved_first_segment, original_item)?;
         ItemInNs::from(ModuleDef::from(matching_module))
     })
 }
diff --git a/crates/ide_db/src/helpers/insert_use/tests.rs b/crates/ide_db/src/helpers/insert_use/tests.rs
index 70b11bf81..5a88ec742 100644
--- a/crates/ide_db/src/helpers/insert_use/tests.rs
+++ b/crates/ide_db/src/helpers/insert_use/tests.rs
@@ -511,13 +511,14 @@ 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};",
     )
 }
 
diff --git a/crates/ide_db/src/helpers/merge_imports.rs b/crates/ide_db/src/helpers/merge_imports.rs
index 0dbabb44f..ec29476a4 100644
--- a/crates/ide_db/src/helpers/merge_imports.rs
+++ b/crates/ide_db/src/helpers/merge_imports.rs
@@ -124,7 +124,7 @@ fn recursive_merge(
                             .map(|tree_list| tree_list.use_trees().any(tree_is_self))
                             .unwrap_or(false)
                     };
-                    match (tree_contains_self(&lhs_t), tree_contains_self(&rhs_t)) {
+                    match (tree_contains_self(lhs_t), tree_contains_self(&rhs_t)) {
                         (true, false) => continue,
                         (false, true) => {
                             *lhs_t = rhs_t;
diff --git a/crates/ide_db/src/lib.rs b/crates/ide_db/src/lib.rs
index 105607dca..7bbd08d6f 100644
--- a/crates/ide_db/src/lib.rs
+++ b/crates/ide_db/src/lib.rs
@@ -3,11 +3,11 @@
 //! 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;
@@ -15,6 +15,9 @@ pub mod traits;
 pub mod call_info;
 pub mod helpers;
 
+pub mod search;
+pub mod rename;
+
 use std::{fmt, sync::Arc};
 
 use base_db::{
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_db/src/search.rs b/crates/ide_db/src/search.rs
index 8152630f5..a840e06a6 100644
--- a/crates/ide_db/src/search.rs
+++ b/crates/ide_db/src/search.rs
@@ -409,7 +409,7 @@ impl<'a> FindUsages<'a> {
                     if let Some(ast::NameLike::NameRef(name_ref)) =
                         sema.find_node_at_offset_with_descend(&tree, offset)
                     {
-                        if self.found_self_ty_name_ref(&self_ty, &name_ref, sink) {
+                        if self.found_self_ty_name_ref(self_ty, &name_ref, sink) {
                             return;
                         }
                     }
@@ -424,7 +424,7 @@ impl<'a> FindUsages<'a> {
         name_ref: &ast::NameRef,
         sink: &mut dyn FnMut(FileId, FileReference) -> bool,
     ) -> bool {
-        match NameRefClass::classify(self.sema, &name_ref) {
+        match NameRefClass::classify(self.sema, name_ref) {
             Some(NameRefClass::Definition(Definition::SelfType(impl_)))
                 if impl_.self_ty(self.sema.db) == *self_ty =>
             {
@@ -464,13 +464,13 @@ impl<'a> FindUsages<'a> {
         name_ref: &ast::NameRef,
         sink: &mut dyn FnMut(FileId, FileReference) -> bool,
     ) -> bool {
-        match NameRefClass::classify(self.sema, &name_ref) {
+        match NameRefClass::classify(self.sema, name_ref) {
             Some(NameRefClass::Definition(def)) if def == self.def => {
                 let FileRange { file_id, range } = self.sema.original_range(name_ref.syntax());
                 let reference = FileReference {
                     range,
                     name: ast::NameLike::NameRef(name_ref.clone()),
-                    access: reference_access(&def, &name_ref),
+                    access: reference_access(&def, name_ref),
                 };
                 sink(file_id, reference)
             }
@@ -480,7 +480,7 @@ impl<'a> FindUsages<'a> {
                     let reference = FileReference {
                         range,
                         name: ast::NameLike::NameRef(name_ref.clone()),
-                        access: reference_access(&def, &name_ref),
+                        access: reference_access(&def, name_ref),
                     };
                     sink(file_id, reference)
                 } else {
@@ -490,11 +490,9 @@ impl<'a> FindUsages<'a> {
             Some(NameRefClass::FieldShorthand { local_ref: local, field_ref: field }) => {
                 let FileRange { file_id, range } = self.sema.original_range(name_ref.syntax());
                 let access = match self.def {
-                    Definition::Field(_) if field == self.def => {
-                        reference_access(&field, &name_ref)
-                    }
+                    Definition::Field(_) if field == self.def => reference_access(&field, name_ref),
                     Definition::Local(l) if local == l => {
-                        reference_access(&Definition::Local(local), &name_ref)
+                        reference_access(&Definition::Local(local), name_ref)
                     }
                     _ => return false,
                 };
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_diagnostics/src/handlers/break_outside_of_loop.rs b/crates/ide_diagnostics/src/handlers/break_outside_of_loop.rs
new file mode 100644
index 000000000..d12594a4c
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/break_outside_of_loop.rs
@@ -0,0 +1,30 @@
+use crate::{Diagnostic, DiagnosticsContext};
+
+// Diagnostic: break-outside-of-loop
+//
+// This diagnostic is triggered if the `break` keyword is used outside of a loop.
+pub(crate) fn break_outside_of_loop(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::BreakOutsideOfLoop,
+) -> Diagnostic {
+    Diagnostic::new(
+        "break-outside-of-loop",
+        "break outside of loop",
+        ctx.sema.diagnostics_display_range(d.expr.clone().map(|it| it.into())).range,
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::check_diagnostics;
+
+    #[test]
+    fn break_outside_of_loop() {
+        check_diagnostics(
+            r#"
+fn foo() { break; }
+         //^^^^^ 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 01bd2dba6..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};
+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),
@@ -46,7 +46,8 @@ fn check_expr_field_shorthand(
 
         let field_range = record_field.syntax().text_range();
         acc.push(
-            Diagnostic::hint(field_range, "Shorthand struct initialization".to_string())
+            Diagnostic::new("use-field-shorthand", "Shorthand struct initialization", field_range)
+                .severity(Severity::WeakWarning)
                 .with_fixes(Some(vec![fix(
                     "use_expr_field_shorthand",
                     "Use struct shorthand initialization",
@@ -85,30 +86,32 @@ fn check_pat_field_shorthand(
         let edit = edit_builder.finish();
 
         let field_range = record_pat_field.syntax().text_range();
-        acc.push(Diagnostic::hint(field_range, "Shorthand struct pattern".to_string()).with_fixes(
-            Some(vec![fix(
-                "use_pat_field_shorthand",
-                "Use struct field shorthand",
-                SourceChange::from_text_edit(file_id, edit),
-                field_range,
-            )]),
-        ));
+        acc.push(
+            Diagnostic::new("use-field-shorthand", "Shorthand struct pattern", field_range)
+                .severity(Severity::WeakWarning)
+                .with_fixes(Some(vec![fix(
+                    "use_pat_field_shorthand",
+                    "Use struct field shorthand",
+                    SourceChange::from_text_edit(file_id, edit),
+                    field_range,
+                )])),
+        );
     }
 }
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::{check_fix, check_no_diagnostics};
+    use crate::tests::{check_diagnostics, check_fix};
 
     #[test]
     fn test_check_expr_field_shorthand() {
-        check_no_diagnostics(
+        check_diagnostics(
             r#"
 struct A { a: &'static str }
 fn main() { A { a: "hello" } }
 "#,
         );
-        check_no_diagnostics(
+        check_diagnostics(
             r#"
 struct A(usize);
 fn main() { A { 0: 0 } }
@@ -154,13 +157,13 @@ fn main() {
 
     #[test]
     fn test_check_pat_field_shorthand() {
-        check_no_diagnostics(
+        check_diagnostics(
             r#"
 struct A { a: &'static str }
 fn f(a: A) { let A { a: hello } = a; }
 "#,
         );
-        check_no_diagnostics(
+        check_diagnostics(
             r#"
 struct A(usize);
 fn f(a: A) { let A { 0: 0 } = a; }
diff --git a/crates/ide_diagnostics/src/handlers/inactive_code.rs b/crates/ide_diagnostics/src/handlers/inactive_code.rs
new file mode 100644
index 000000000..dfd0e3351
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/inactive_code.rs
@@ -0,0 +1,116 @@
+use cfg::DnfExpr;
+use stdx::format_to;
+
+use crate::{Diagnostic, DiagnosticsContext, Severity};
+
+// Diagnostic: inactive-code
+//
+// This diagnostic is shown for code with inactive `#[cfg]` attributes.
+pub(crate) fn inactive_code(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::InactiveCode,
+) -> Option<Diagnostic> {
+    // If there's inactive code somewhere in a macro, don't propagate to the call-site.
+    if d.node.file_id.expansion_info(ctx.sema.db).is_some() {
+        return None;
+    }
+
+    let inactive = DnfExpr::new(d.cfg.clone()).why_inactive(&d.opts);
+    let mut message = "code is inactive due to #[cfg] directives".to_string();
+
+    if let Some(inactive) = inactive {
+        format_to!(message, ": {}", inactive);
+    }
+
+    let res = Diagnostic::new(
+        "inactive-code",
+        message,
+        ctx.sema.diagnostics_display_range(d.node.clone()).range,
+    )
+    .severity(Severity::WeakWarning)
+    .with_unused(true);
+    Some(res)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{tests::check_diagnostics_with_config, DiagnosticsConfig};
+
+    pub(crate) fn check(ra_fixture: &str) {
+        let config = DiagnosticsConfig::default();
+        check_diagnostics_with_config(config, ra_fixture)
+    }
+
+    #[test]
+    fn cfg_diagnostics() {
+        check(
+            r#"
+fn f() {
+    // The three g̶e̶n̶d̶e̶r̶s̶ statements:
+
+    #[cfg(a)] fn f() {}  // Item statement
+  //^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: a is disabled
+    #[cfg(a)] {}         // Expression statement
+  //^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: a is disabled
+    #[cfg(a)] let x = 0; // let statement
+  //^^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: a is disabled
+
+    abc(#[cfg(a)] 0);
+      //^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: a is disabled
+    let x = Struct {
+        #[cfg(a)] f: 0,
+      //^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: a is disabled
+    };
+    match () {
+        () => (),
+        #[cfg(a)] () => (),
+      //^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: a is disabled
+    }
+
+    #[cfg(a)] 0          // Trailing expression of block
+  //^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: a is disabled
+}
+        "#,
+        );
+    }
+
+    #[test]
+    fn inactive_item() {
+        // Additional tests in `cfg` crate. This only tests disabled cfgs.
+
+        check(
+            r#"
+    #[cfg(no)] pub fn f() {}
+  //^^^^^^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: no is disabled
+
+    #[cfg(no)] #[cfg(no2)] mod m;
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: no and no2 are disabled
+
+    #[cfg(all(not(a), b))] enum E {}
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: b is disabled
+
+    #[cfg(feature = "std")] use std;
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: feature = "std" is disabled
+"#,
+        );
+    }
+
+    /// Tests that `cfg` attributes behind `cfg_attr` is handled properly.
+    #[test]
+    fn inactive_via_cfg_attr() {
+        cov_mark::check!(cfg_attr_active);
+        check(
+            r#"
+    #[cfg_attr(not(never), cfg(no))] fn f() {}
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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() {}
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ weak: code is inactive due to #[cfg] directives: no is disabled
+"#,
+        );
+    }
+}
diff --git a/crates/ide_diagnostics/src/handlers/incorrect_case.rs b/crates/ide_diagnostics/src/handlers/incorrect_case.rs
new file mode 100644
index 000000000..68f25f284
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/incorrect_case.rs
@@ -0,0 +1,459 @@
+use hir::{db::AstDatabase, InFile};
+use ide_db::{assists::Assist, defs::NameClass};
+use syntax::AstNode;
+
+use crate::{
+    // 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(crate) fn incorrect_case(ctx: &DiagnosticsContext<'_>, d: &hir::IncorrectCase) -> Diagnostic {
+    Diagnostic::new(
+        "incorrect-ident-case",
+        format!(
+            "{} `{}` should have {} name, e.g. `{}`",
+            d.ident_type, d.ident_text, d.expected_case, d.suggested_text
+        ),
+        ctx.sema.diagnostics_display_range(InFile::new(d.file, d.ident.clone().into())).range,
+    )
+    .severity(Severity::WeakWarning)
+    .with_fixes(fixes(ctx, d))
+}
+
+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 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 = def.rename(&ctx.sema, &d.suggested_text);
+        res.source_change = Some(source_change.ok().unwrap_or_default());
+    }
+
+    Some(vec![res])
+}
+
+#[cfg(test)]
+mod change_case {
+    use crate::tests::{check_diagnostics, check_fix};
+
+    #[test]
+    fn test_rename_incorrect_case() {
+        check_fix(
+            r#"
+pub struct test_struct$0 { one: i32 }
+
+pub fn some_fn(val: test_struct) -> test_struct {
+    test_struct { one: val.one + 1 }
+}
+"#,
+            r#"
+pub struct TestStruct { one: i32 }
+
+pub fn some_fn(val: TestStruct) -> TestStruct {
+    TestStruct { one: val.one + 1 }
+}
+"#,
+        );
+
+        check_fix(
+            r#"
+pub fn some_fn(NonSnakeCase$0: u8) -> u8 {
+    NonSnakeCase
+}
+"#,
+            r#"
+pub fn some_fn(non_snake_case: u8) -> u8 {
+    non_snake_case
+}
+"#,
+        );
+
+        check_fix(
+            r#"
+pub fn SomeFn$0(val: u8) -> u8 {
+    if val != 0 { SomeFn(val - 1) } else { val }
+}
+"#,
+            r#"
+pub fn some_fn(val: u8) -> u8 {
+    if val != 0 { some_fn(val - 1) } else { val }
+}
+"#,
+        );
+
+        check_fix(
+            r#"
+fn some_fn() {
+    let whatAWeird_Formatting$0 = 10;
+    another_func(whatAWeird_Formatting);
+}
+"#,
+            r#"
+fn some_fn() {
+    let what_a_weird_formatting = 10;
+    another_func(what_a_weird_formatting);
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn test_uppercase_const_no_diagnostics() {
+        check_diagnostics(
+            r#"
+fn foo() {
+    const ANOTHER_ITEM: &str = "some_item";
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn test_rename_incorrect_case_struct_method() {
+        check_fix(
+            r#"
+pub struct TestStruct;
+
+impl TestStruct {
+    pub fn SomeFn$0() -> TestStruct {
+        TestStruct
+    }
+}
+"#,
+            r#"
+pub struct TestStruct;
+
+impl TestStruct {
+    pub fn some_fn() -> TestStruct {
+        TestStruct
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn test_single_incorrect_case_diagnostic_in_function_name_issue_6970() {
+        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]
+    fn incorrect_function_name() {
+        check_diagnostics(
+            r#"
+fn NonSnakeCaseName() {}
+// ^^^^^^^^^^^^^^^^ 💡 weak: Function `NonSnakeCaseName` should have snake_case name, e.g. `non_snake_case_name`
+"#,
+        );
+    }
+
+    #[test]
+    fn incorrect_function_params() {
+        check_diagnostics(
+            r#"
+fn foo(SomeParam: u8) {}
+    // ^^^^^^^^^ 💡 weak: Parameter `SomeParam` should have snake_case name, e.g. `some_param`
+
+fn foo2(ok_param: &str, CAPS_PARAM: u8) {}
+                     // ^^^^^^^^^^ 💡 weak: Parameter `CAPS_PARAM` should have snake_case name, e.g. `caps_param`
+"#,
+        );
+    }
+
+    #[test]
+    fn incorrect_variable_names() {
+        check_diagnostics(
+            r#"
+fn foo() {
+    let SOME_VALUE = 10;
+     // ^^^^^^^^^^ 💡 weak: Variable `SOME_VALUE` should have snake_case name, e.g. `some_value`
+    let AnotherValue = 20;
+     // ^^^^^^^^^^^^ 💡 weak: Variable `AnotherValue` should have snake_case name, e.g. `another_value`
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn incorrect_struct_names() {
+        check_diagnostics(
+            r#"
+struct non_camel_case_name {}
+    // ^^^^^^^^^^^^^^^^^^^ 💡 weak: Structure `non_camel_case_name` should have CamelCase name, e.g. `NonCamelCaseName`
+
+struct SCREAMING_CASE {}
+    // ^^^^^^^^^^^^^^ 💡 weak: Structure `SCREAMING_CASE` should have CamelCase name, e.g. `ScreamingCase`
+"#,
+        );
+    }
+
+    #[test]
+    fn no_diagnostic_for_camel_cased_acronyms_in_struct_name() {
+        check_diagnostics(
+            r#"
+struct AABB {}
+"#,
+        );
+    }
+
+    #[test]
+    fn incorrect_struct_field() {
+        check_diagnostics(
+            r#"
+struct SomeStruct { SomeField: u8 }
+                 // ^^^^^^^^^ 💡 weak: Field `SomeField` should have snake_case name, e.g. `some_field`
+"#,
+        );
+    }
+
+    #[test]
+    fn incorrect_enum_names() {
+        check_diagnostics(
+            r#"
+enum some_enum { Val(u8) }
+  // ^^^^^^^^^ 💡 weak: Enum `some_enum` should have CamelCase name, e.g. `SomeEnum`
+
+enum SOME_ENUM {}
+  // ^^^^^^^^^ 💡 weak: Enum `SOME_ENUM` should have CamelCase name, e.g. `SomeEnum`
+"#,
+        );
+    }
+
+    #[test]
+    fn no_diagnostic_for_camel_cased_acronyms_in_enum_name() {
+        check_diagnostics(
+            r#"
+enum AABB {}
+"#,
+        );
+    }
+
+    #[test]
+    fn incorrect_enum_variant_name() {
+        check_diagnostics(
+            r#"
+enum SomeEnum { SOME_VARIANT(u8) }
+             // ^^^^^^^^^^^^ 💡 weak: Variant `SOME_VARIANT` should have CamelCase name, e.g. `SomeVariant`
+"#,
+        );
+    }
+
+    #[test]
+    fn incorrect_const_name() {
+        check_diagnostics(
+            r#"
+const some_weird_const: u8 = 10;
+   // ^^^^^^^^^^^^^^^^ 💡 weak: Constant `some_weird_const` should have UPPER_SNAKE_CASE name, e.g. `SOME_WEIRD_CONST`
+"#,
+        );
+    }
+
+    #[test]
+    fn incorrect_static_name() {
+        check_diagnostics(
+            r#"
+static some_weird_const: u8 = 10;
+    // ^^^^^^^^^^^^^^^^ 💡 weak: Static variable `some_weird_const` should have UPPER_SNAKE_CASE name, e.g. `SOME_WEIRD_CONST`
+"#,
+        );
+    }
+
+    #[test]
+    fn fn_inside_impl_struct() {
+        check_diagnostics(
+            r#"
+struct someStruct;
+    // ^^^^^^^^^^ 💡 weak: Structure `someStruct` should have CamelCase name, e.g. `SomeStruct`
+
+impl someStruct {
+    fn SomeFunc(&self) {
+    // ^^^^^^^^ 💡 weak: Function `SomeFunc` should have snake_case name, e.g. `some_func`
+        let WHY_VAR_IS_CAPS = 10;
+         // ^^^^^^^^^^^^^^^ 💡 weak: Variable `WHY_VAR_IS_CAPS` should have snake_case name, e.g. `why_var_is_caps`
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn no_diagnostic_for_enum_varinats() {
+        check_diagnostics(
+            r#"
+enum Option { Some, None }
+
+fn main() {
+    match Option::None {
+        None => (),
+        Some => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn non_let_bind() {
+        check_diagnostics(
+            r#"
+enum Option { Some, None }
+
+fn main() {
+    match Option::None {
+        SOME_VAR @ None => (),
+     // ^^^^^^^^ 💡 weak: Variable `SOME_VAR` should have snake_case name, e.g. `some_var`
+        Some => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn allow_attributes_crate_attr() {
+        check_diagnostics(
+            r#"
+#![allow(non_snake_case)]
+
+mod F {
+    fn CheckItWorksWithCrateAttr(BAD_NAME_HI: u8) {}
+}
+    "#,
+        );
+    }
+
+    #[test]
+    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() {
+        #[allow(non_snake_case)]
+        trait __BitFlagsOk {
+            const HiImAlsoBad: u8 = 2;
+            fn Dirty(&self) -> bool { false }
+        }
+
+        trait __BitFlagsBad {
+            const HiImAlsoBad: u8 = 2;
+            fn Dirty(&self) -> bool { false }
+        }
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn infinite_loop_inner_items() {
+        check_diagnostics(
+            r#"
+fn qualify() {
+    mod foo {
+        use super::*;
+    }
+}
+            "#,
+        )
+    }
+
+    #[test] // Issue #8809.
+    fn parenthesized_parameter() {
+        check_diagnostics(r#"fn f((O): _) {}"#)
+    }
+
+    #[test]
+    fn ignores_extern_items() {
+        cov_mark::check!(extern_func_incorrect_case_ignored);
+        cov_mark::check!(extern_static_incorrect_case_ignored);
+        check_diagnostics(
+            r#"
+extern {
+    fn NonSnakeCaseName(SOME_VAR: u8) -> u8;
+    pub static SomeStatic: u8 = 10;
+}
+            "#,
+        );
+    }
+
+    #[test]
+    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 {
+    fn BAD_FUNCTION();
+    fn BadFunction();
+}
+    "#,
+        );
+    }
+
+    #[test]
+    fn allow_attributes() {
+        check_diagnostics(
+            r#"
+#[allow(non_snake_case)]
+fn NonSnakeCaseName(SOME_VAR: u8) -> u8{
+    // cov_flags generated output from elsewhere in this file
+    extern "C" {
+        #[no_mangle]
+        static lower_case: u8;
+    }
+
+    let OtherVar = SOME_VAR + 1;
+    OtherVar
+}
+
+#[allow(nonstandard_style)]
+mod CheckNonstandardStyle {
+    fn HiImABadFnName() {}
+}
+
+#[allow(bad_style)]
+mod CheckBadStyle {
+    fn HiImABadFnName() {}
+}
+
+mod F {
+    #![allow(non_snake_case)]
+    fn CheckItWorksWithModAttr(BAD_NAME_HI: u8) {}
+}
+
+#[allow(non_snake_case, non_camel_case_types)]
+pub struct some_type {
+    SOME_FIELD: u8,
+    SomeField: u16,
+}
+
+#[allow(non_upper_case_globals)]
+pub const some_const: u8 = 10;
+
+#[allow(non_upper_case_globals)]
+pub static SomeStatic: u8 = 10;
+    "#,
+        );
+    }
+}
diff --git a/crates/ide_diagnostics/src/handlers/macro_error.rs b/crates/ide_diagnostics/src/handlers/macro_error.rs
new file mode 100644
index 000000000..356f089b2
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/macro_error.rs
@@ -0,0 +1,173 @@
+use crate::{Diagnostic, DiagnosticsContext};
+
+// Diagnostic: macro-error
+//
+// This diagnostic is shown for macro expansion errors.
+pub(crate) fn macro_error(ctx: &DiagnosticsContext<'_>, d: &hir::MacroError) -> Diagnostic {
+    Diagnostic::new(
+        "macro-error",
+        d.message.clone(),
+        ctx.sema.diagnostics_display_range(d.node.clone()).range,
+    )
+    .experimental()
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{
+        tests::{check_diagnostics, check_diagnostics_with_config},
+        DiagnosticsConfig,
+    };
+
+    #[test]
+    fn builtin_macro_fails_expansion() {
+        check_diagnostics(
+            r#"
+#[rustc_builtin_macro]
+macro_rules! include { () => {} }
+
+  include!("doesntexist");
+//^^^^^^^^^^^^^^^^^^^^^^^^ error: failed to load file `doesntexist`
+            "#,
+        );
+    }
+
+    #[test]
+    fn include_macro_should_allow_empty_content() {
+        let mut config = DiagnosticsConfig::default();
+
+        // FIXME: This is a false-positive, the file is actually linked in via
+        // `include!` macro
+        config.disabled.insert("unlinked-file".to_string());
+
+        check_diagnostics_with_config(
+            config,
+            r#"
+//- /lib.rs
+#[rustc_builtin_macro]
+macro_rules! include { () => {} }
+
+include!("foo/bar.rs");
+//- /foo/bar.rs
+// empty
+"#,
+        );
+    }
+
+    #[test]
+    fn good_out_dir_diagnostic() {
+        check_diagnostics(
+            r#"
+#[rustc_builtin_macro]
+macro_rules! include { () => {} }
+#[rustc_builtin_macro]
+macro_rules! env { () => {} }
+#[rustc_builtin_macro]
+macro_rules! concat { () => {} }
+
+  include!(concat!(env!("OUT_DIR"), "/out.rs"));
+//^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: `OUT_DIR` not set, enable "run build scripts" to fix
+"#,
+        );
+    }
+
+    #[test]
+    fn register_attr_and_tool() {
+        cov_mark::check!(register_attr);
+        cov_mark::check!(register_tool);
+        check_diagnostics(
+            r#"
+#![register_tool(tool)]
+#![register_attr(attr)]
+
+#[tool::path]
+#[attr]
+struct S;
+"#,
+        );
+        // NB: we don't currently emit diagnostics here
+    }
+
+    #[test]
+    fn macro_diag_builtin() {
+        check_diagnostics(
+            r#"
+#[rustc_builtin_macro]
+macro_rules! env {}
+
+#[rustc_builtin_macro]
+macro_rules! include {}
+
+#[rustc_builtin_macro]
+macro_rules! compile_error {}
+
+#[rustc_builtin_macro]
+macro_rules! format_args { () => {} }
+
+fn main() {
+    // Test a handful of built-in (eager) macros:
+
+    include!(invalid);
+  //^^^^^^^^^^^^^^^^^ error: could not convert tokens
+    include!("does not exist");
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^ error: failed to load file `does not exist`
+
+    env!(invalid);
+  //^^^^^^^^^^^^^ error: could not convert tokens
+
+    env!("OUT_DIR");
+  //^^^^^^^^^^^^^^^ error: `OUT_DIR` not set, enable "run build scripts" to fix
+
+    compile_error!("compile_error works");
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: compile_error works
+
+    // Lazy:
+
+    format_args!();
+  //^^^^^^^^^^^^^^ error: no rule matches input tokens
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn macro_rules_diag() {
+        check_diagnostics(
+            r#"
+macro_rules! m {
+    () => {};
+}
+fn f() {
+    m!();
+
+    m!(hi);
+  //^^^^^^ error: leftover tokens
+}
+      "#,
+        );
+    }
+    #[test]
+    fn dollar_crate_in_builtin_macro() {
+        check_diagnostics(
+            r#"
+#[macro_export]
+#[rustc_builtin_macro]
+macro_rules! format_args {}
+
+#[macro_export]
+macro_rules! arg { () => {} }
+
+#[macro_export]
+macro_rules! outer {
+    () => {
+        $crate::format_args!( "", $crate::arg!(1) )
+    };
+}
+
+fn f() {
+    outer!();
+} //^^^^^^^^ error: leftover tokens
+"#,
+        )
+    }
+}
diff --git a/crates/ide_diagnostics/src/handlers/mismatched_arg_count.rs b/crates/ide_diagnostics/src/handlers/mismatched_arg_count.rs
new file mode 100644
index 000000000..a9b6d3870
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/mismatched_arg_count.rs
@@ -0,0 +1,272 @@
+use crate::{Diagnostic, DiagnosticsContext};
+
+// Diagnostic: mismatched-arg-count
+//
+// This diagnostic is triggered if a function is invoked with an incorrect amount of arguments.
+pub(crate) fn mismatched_arg_count(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::MismatchedArgCount,
+) -> Diagnostic {
+    let s = if d.expected == 1 { "" } else { "s" };
+    let message = format!("expected {} argument{}, found {}", d.expected, s, d.found);
+    Diagnostic::new(
+        "mismatched-arg-count",
+        message,
+        ctx.sema.diagnostics_display_range(d.call_expr.clone().map(|it| it.into())).range,
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::check_diagnostics;
+
+    #[test]
+    fn simple_free_fn_zero() {
+        check_diagnostics(
+            r#"
+fn zero() {}
+fn f() { zero(1); }
+       //^^^^^^^ error: expected 0 arguments, found 1
+"#,
+        );
+
+        check_diagnostics(
+            r#"
+fn zero() {}
+fn f() { zero(); }
+"#,
+        );
+    }
+
+    #[test]
+    fn simple_free_fn_one() {
+        check_diagnostics(
+            r#"
+fn one(arg: u8) {}
+fn f() { one(); }
+       //^^^^^ error: expected 1 argument, found 0
+"#,
+        );
+
+        check_diagnostics(
+            r#"
+fn one(arg: u8) {}
+fn f() { one(1); }
+"#,
+        );
+    }
+
+    #[test]
+    fn method_as_fn() {
+        check_diagnostics(
+            r#"
+struct S;
+impl S { fn method(&self) {} }
+
+fn f() {
+    S::method();
+} //^^^^^^^^^^^ error: expected 1 argument, found 0
+"#,
+        );
+
+        check_diagnostics(
+            r#"
+struct S;
+impl S { fn method(&self) {} }
+
+fn f() {
+    S::method(&S);
+    S.method();
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn method_with_arg() {
+        check_diagnostics(
+            r#"
+struct S;
+impl S { fn method(&self, arg: u8) {} }
+
+            fn f() {
+                S.method();
+            } //^^^^^^^^^^ error: expected 1 argument, found 0
+            "#,
+        );
+
+        check_diagnostics(
+            r#"
+struct S;
+impl S { fn method(&self, arg: u8) {} }
+
+fn f() {
+    S::method(&S, 0);
+    S.method(1);
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn method_unknown_receiver() {
+        // note: this is incorrect code, so there might be errors on this in the
+        // future, but we shouldn't emit an argument count diagnostic here
+        check_diagnostics(
+            r#"
+trait Foo { fn method(&self, arg: usize) {} }
+
+fn f() {
+    let x;
+    x.method();
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn tuple_struct() {
+        check_diagnostics(
+            r#"
+struct Tup(u8, u16);
+fn f() {
+    Tup(0);
+} //^^^^^^ error: expected 2 arguments, found 1
+"#,
+        )
+    }
+
+    #[test]
+    fn enum_variant() {
+        check_diagnostics(
+            r#"
+enum En { Variant(u8, u16), }
+fn f() {
+    En::Variant(0);
+} //^^^^^^^^^^^^^^ error: expected 2 arguments, found 1
+"#,
+        )
+    }
+
+    #[test]
+    fn enum_variant_type_macro() {
+        check_diagnostics(
+            r#"
+macro_rules! Type {
+    () => { u32 };
+}
+enum Foo {
+    Bar(Type![])
+}
+impl Foo {
+    fn new() {
+        Foo::Bar(0);
+        Foo::Bar(0, 1);
+      //^^^^^^^^^^^^^^ error: expected 1 argument, found 2
+        Foo::Bar();
+      //^^^^^^^^^^ error: expected 1 argument, found 0
+    }
+}
+        "#,
+        );
+    }
+
+    #[test]
+    fn varargs() {
+        check_diagnostics(
+            r#"
+extern "C" {
+    fn fixed(fixed: u8);
+    fn varargs(fixed: u8, ...);
+    fn varargs2(...);
+}
+
+fn f() {
+    unsafe {
+        fixed(0);
+        fixed(0, 1);
+      //^^^^^^^^^^^ error: expected 1 argument, found 2
+        varargs(0);
+        varargs(0, 1);
+        varargs2();
+        varargs2(0);
+        varargs2(0, 1);
+    }
+}
+        "#,
+        )
+    }
+
+    #[test]
+    fn arg_count_lambda() {
+        check_diagnostics(
+            r#"
+fn main() {
+    let f = |()| ();
+    f();
+  //^^^ error: expected 1 argument, found 0
+    f(());
+    f((), ());
+  //^^^^^^^^^ error: expected 1 argument, found 2
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn cfgd_out_call_arguments() {
+        check_diagnostics(
+            r#"
+struct C(#[cfg(FALSE)] ());
+impl C {
+    fn new() -> Self {
+        Self(
+            #[cfg(FALSE)]
+            (),
+        )
+    }
+
+    fn method(&self) {}
+}
+
+fn main() {
+    C::new().method(#[cfg(FALSE)] 0);
+}
+            "#,
+        );
+    }
+
+    #[test]
+    fn cfgd_out_fn_params() {
+        check_diagnostics(
+            r#"
+fn foo(#[cfg(NEVER)] x: ()) {}
+
+struct S;
+
+impl S {
+    fn method(#[cfg(NEVER)] self) {}
+    fn method2(#[cfg(NEVER)] self, arg: u8) {}
+    fn method3(self, #[cfg(NEVER)] arg: u8) {}
+}
+
+extern "C" {
+    fn fixed(fixed: u8, #[cfg(NEVER)] ...);
+    fn varargs(#[cfg(not(NEVER))] ...);
+}
+
+fn main() {
+    foo();
+    S::method();
+    S::method2(0);
+    S::method3(S);
+    S.method3();
+    unsafe {
+        fixed(0);
+        varargs(1, 2, 3);
+    }
+}
+            "#,
+        )
+    }
+}
diff --git a/crates/ide_diagnostics/src/handlers/missing_fields.rs b/crates/ide_diagnostics/src/handlers/missing_fields.rs
new file mode 100644
index 000000000..bc56e0342
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/missing_fields.rs
@@ -0,0 +1,355 @@
+use either::Either;
+use hir::{db::AstDatabase, InFile};
+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::{fix, Diagnostic, DiagnosticsContext};
+
+// Diagnostic: missing-fields
+//
+// This diagnostic is triggered if record lacks some fields that exist in the corresponding structure.
+//
+// Example:
+//
+// ```rust
+// struct A { a: u8, b: u8 }
+//
+// let a = A { a: 10 };
+// ```
+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);
+    }
+
+    let ptr = InFile::new(
+        d.file,
+        d.field_list_parent_path
+            .clone()
+            .map(SyntaxNodePtr::from)
+            .unwrap_or_else(|| d.field_list_parent.clone().either(|it| it.into(), |it| it.into())),
+    );
+
+    Diagnostic::new("missing-fields", message, ctx.sema.diagnostics_display_range(ptr).range)
+        .with_fixes(fixes(ctx, d))
+}
+
+fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::MissingFields) -> Option<Vec<Assist>> {
+    // Note that although we could add a diagnostics to
+    // fill the missing tuple field, e.g :
+    // `struct A(usize);`
+    // `let a = A { 0: () }`
+    // but it is uncommon usage and it should not be encouraged.
+    if d.missed_fields.iter().any(|it| it.as_tuple_index().is_some()) {
+        return None;
+    }
+
+    let root = ctx.sema.db.parse_or_expand(d.file)?;
+    let field_list_parent = match &d.field_list_parent {
+        Either::Left(record_expr) => record_expr.to_node(&root),
+        // FIXE: patterns should be fixable as well.
+        Either::Right(_) => return None,
+    };
+    let old_field_list = field_list_parent.record_expr_field_list()?;
+    let new_field_list = old_field_list.clone_for_update();
+    for f in d.missed_fields.iter() {
+        let field =
+            make::record_expr_field(make::name_ref(&f.to_string()), Some(make::expr_unit()))
+                .clone_for_update();
+        new_field_list.add_field(field);
+    }
+
+    let edit = {
+        let mut builder = TextEdit::builder();
+        algo::diff(old_field_list.syntax(), new_field_list.syntax()).into_text_edit(&mut builder);
+        builder.finish()
+    };
+    Some(vec![fix(
+        "fill_missing_fields",
+        "Fill struct fields",
+        SourceChange::from_text_edit(d.file.original_file(ctx.sema.db), edit),
+        ctx.sema.original_range(field_list_parent.syntax()).range,
+    )])
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_diagnostics, check_fix};
+
+    #[test]
+    fn missing_record_pat_field_diagnostic() {
+        check_diagnostics(
+            r#"
+struct S { foo: i32, bar: () }
+fn baz(s: S) {
+    let S { foo: _ } = s;
+      //^ error: missing structure fields:
+      //| - bar
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn missing_record_pat_field_no_diagnostic_if_not_exhaustive() {
+        check_diagnostics(
+            r"
+struct S { foo: i32, bar: () }
+fn baz(s: S) -> i32 {
+    match s {
+        S { foo, .. } => foo,
+    }
+}
+",
+        )
+    }
+
+    #[test]
+    fn missing_record_pat_field_box() {
+        check_diagnostics(
+            r"
+struct S { s: Box<u32> }
+fn x(a: S) {
+    let S { box s } = a;
+}
+",
+        )
+    }
+
+    #[test]
+    fn missing_record_pat_field_ref() {
+        check_diagnostics(
+            r"
+struct S { s: u32 }
+fn x(a: S) {
+    let S { ref s } = a;
+}
+",
+        )
+    }
+
+    #[test]
+    fn range_mapping_out_of_macros() {
+        // FIXME: this is very wrong, but somewhat tricky to fix.
+        check_fix(
+            r#"
+fn some() {}
+fn items() {}
+fn here() {}
+
+macro_rules! id { ($($tt:tt)*) => { $($tt)*}; }
+
+fn main() {
+    let _x = id![Foo { a: $042 }];
+}
+
+pub struct Foo { pub a: i32, pub b: i32 }
+"#,
+            r#"
+fn some(, b: () ) {}
+fn items() {}
+fn here() {}
+
+macro_rules! id { ($($tt:tt)*) => { $($tt)*}; }
+
+fn main() {
+    let _x = id![Foo { a: 42 }];
+}
+
+pub struct Foo { pub a: i32, pub b: i32 }
+"#,
+        );
+    }
+
+    #[test]
+    fn test_fill_struct_fields_empty() {
+        check_fix(
+            r#"
+struct TestStruct { one: i32, two: i64 }
+
+fn test_fn() {
+    let s = TestStruct {$0};
+}
+"#,
+            r#"
+struct TestStruct { one: i32, two: i64 }
+
+fn test_fn() {
+    let s = TestStruct { one: (), two: () };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn test_fill_struct_fields_self() {
+        check_fix(
+            r#"
+struct TestStruct { one: i32 }
+
+impl TestStruct {
+    fn test_fn() { let s = Self {$0}; }
+}
+"#,
+            r#"
+struct TestStruct { one: i32 }
+
+impl TestStruct {
+    fn test_fn() { let s = Self { one: () }; }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn test_fill_struct_fields_enum() {
+        check_fix(
+            r#"
+enum Expr {
+    Bin { lhs: Box<Expr>, rhs: Box<Expr> }
+}
+
+impl Expr {
+    fn new_bin(lhs: Box<Expr>, rhs: Box<Expr>) -> Expr {
+        Expr::Bin {$0 }
+    }
+}
+"#,
+            r#"
+enum Expr {
+    Bin { lhs: Box<Expr>, rhs: Box<Expr> }
+}
+
+impl Expr {
+    fn new_bin(lhs: Box<Expr>, rhs: Box<Expr>) -> Expr {
+        Expr::Bin { lhs: (), rhs: () }
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn test_fill_struct_fields_partial() {
+        check_fix(
+            r#"
+struct TestStruct { one: i32, two: i64 }
+
+fn test_fn() {
+    let s = TestStruct{ two: 2$0 };
+}
+"#,
+            r"
+struct TestStruct { one: i32, two: i64 }
+
+fn test_fn() {
+    let s = TestStruct{ two: 2, one: () };
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_fill_struct_fields_raw_ident() {
+        check_fix(
+            r#"
+struct TestStruct { r#type: u8 }
+
+fn test_fn() {
+    TestStruct { $0 };
+}
+"#,
+            r"
+struct TestStruct { r#type: u8 }
+
+fn test_fn() {
+    TestStruct { r#type: ()  };
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_fill_struct_fields_no_diagnostic() {
+        check_diagnostics(
+            r#"
+struct TestStruct { one: i32, two: i64 }
+
+fn test_fn() {
+    let one = 1;
+    let s = TestStruct{ one, two: 2 };
+}
+        "#,
+        );
+    }
+
+    #[test]
+    fn test_fill_struct_fields_no_diagnostic_on_spread() {
+        check_diagnostics(
+            r#"
+struct TestStruct { one: i32, two: i64 }
+
+fn test_fn() {
+    let one = 1;
+    let s = TestStruct{ ..a };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn test_fill_struct_fields_blank_line() {
+        check_fix(
+            r#"
+struct S { a: (), b: () }
+
+fn f() {
+    S {
+        $0
+    };
+}
+"#,
+            r#"
+struct S { a: (), b: () }
+
+fn f() {
+    S {
+        a: (),
+        b: (),
+    };
+}
+"#,
+        );
+    }
+
+    #[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_diagnostics/src/handlers/missing_match_arms.rs b/crates/ide_diagnostics/src/handlers/missing_match_arms.rs
new file mode 100644
index 000000000..947b0f2e2
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/missing_match_arms.rs
@@ -0,0 +1,929 @@
+use hir::InFile;
+
+use crate::{Diagnostic, DiagnosticsContext};
+
+// Diagnostic: missing-match-arm
+//
+// This diagnostic is triggered if `match` block is missing one or more match arms.
+pub(crate) fn missing_match_arms(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::MissingMatchArms,
+) -> Diagnostic {
+    Diagnostic::new(
+        "missing-match-arm",
+        "missing match arm",
+        ctx.sema.diagnostics_display_range(InFile::new(d.file, d.match_expr.clone().into())).range,
+    )
+}
+
+#[cfg(test)]
+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::tests::check_diagnostics(ra_fixture)
+    }
+
+    #[test]
+    fn empty_tuple() {
+        check_diagnostics_no_bails(
+            r#"
+fn main() {
+    match () { }
+        //^^ error: missing match arm
+    match (()) { }
+        //^^^^ error: missing match arm
+
+    match () { _ => (), }
+    match () { () => (), }
+    match (()) { (()) => (), }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn tuple_of_two_empty_tuple() {
+        check_diagnostics_no_bails(
+            r#"
+fn main() {
+    match ((), ()) { }
+        //^^^^^^^^ error: missing match arm
+
+    match ((), ()) { ((), ()) => (), }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn boolean() {
+        check_diagnostics_no_bails(
+            r#"
+fn test_main() {
+    match false { }
+        //^^^^^ error: missing match arm
+    match false { true => (), }
+        //^^^^^ error: missing match arm
+    match (false, true) {}
+        //^^^^^^^^^^^^^ error: missing match arm
+    match (false, true) { (true, true) => (), }
+        //^^^^^^^^^^^^^ error: missing match arm
+    match (false, true) {
+        //^^^^^^^^^^^^^ error: missing match arm
+        (false, true) => (),
+        (false, false) => (),
+        (true, false) => (),
+    }
+    match (false, true) { (true, _x) => (), }
+        //^^^^^^^^^^^^^ error: missing match arm
+
+    match false { true => (), false => (), }
+    match (false, true) {
+        (false, _) => (),
+        (true, false) => (),
+        (_, true) => (),
+    }
+    match (false, true) {
+        (true, true) => (),
+        (true, false) => (),
+        (false, true) => (),
+        (false, false) => (),
+    }
+    match (false, true) {
+        (true, _x) => (),
+        (false, true) => (),
+        (false, false) => (),
+    }
+    match (false, true, false) {
+        (false, ..) => (),
+        (true, ..) => (),
+    }
+    match (false, true, false) {
+        (.., false) => (),
+        (.., true) => (),
+    }
+    match (false, true, false) { (..) => (), }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn tuple_of_tuple_and_bools() {
+        check_diagnostics_no_bails(
+            r#"
+fn main() {
+    match (false, ((), false)) {}
+        //^^^^^^^^^^^^^^^^^^^^ error: missing match arm
+    match (false, ((), false)) { (true, ((), true)) => (), }
+        //^^^^^^^^^^^^^^^^^^^^ error: missing match arm
+    match (false, ((), false)) { (true, _) => (), }
+        //^^^^^^^^^^^^^^^^^^^^ error: missing match arm
+
+    match (false, ((), false)) {
+        (true, ((), true)) => (),
+        (true, ((), false)) => (),
+        (false, ((), true)) => (),
+        (false, ((), false)) => (),
+    }
+    match (false, ((), false)) {
+        (true, ((), true)) => (),
+        (true, ((), false)) => (),
+        (false, _) => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn enums() {
+        check_diagnostics_no_bails(
+            r#"
+enum Either { A, B, }
+
+fn main() {
+    match Either::A { }
+        //^^^^^^^^^ error: missing match arm
+    match Either::B { Either::A => (), }
+        //^^^^^^^^^ error: missing match arm
+
+    match &Either::B {
+        //^^^^^^^^^^ error: missing match arm
+        Either::A => (),
+    }
+
+    match Either::B {
+        Either::A => (), Either::B => (),
+    }
+    match &Either::B {
+        Either::A => (), Either::B => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn enum_containing_bool() {
+        check_diagnostics_no_bails(
+            r#"
+enum Either { A(bool), B }
+
+fn main() {
+    match Either::B { }
+        //^^^^^^^^^ error: missing match arm
+    match Either::B {
+        //^^^^^^^^^ error: missing match arm
+        Either::A(true) => (), Either::B => ()
+    }
+
+    match Either::B {
+        Either::A(true) => (),
+        Either::A(false) => (),
+        Either::B => (),
+    }
+    match Either::B {
+        Either::B => (),
+        _ => (),
+    }
+    match Either::B {
+        Either::A(_) => (),
+        Either::B => (),
+    }
+
+}
+        "#,
+        );
+    }
+
+    #[test]
+    fn enum_different_sizes() {
+        check_diagnostics_no_bails(
+            r#"
+enum Either { A(bool), B(bool, bool) }
+
+fn main() {
+    match Either::A(false) {
+        //^^^^^^^^^^^^^^^^ error: missing match arm
+        Either::A(_) => (),
+        Either::B(false, _) => (),
+    }
+
+    match Either::A(false) {
+        Either::A(_) => (),
+        Either::B(true, _) => (),
+        Either::B(false, _) => (),
+    }
+    match Either::A(false) {
+        Either::A(true) | Either::A(false) => (),
+        Either::B(true, _) => (),
+        Either::B(false, _) => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn tuple_of_enum_no_diagnostic() {
+        check_diagnostics_no_bails(
+            r#"
+enum Either { A(bool), B(bool, bool) }
+enum Either2 { C, D }
+
+fn main() {
+    match (Either::A(false), Either2::C) {
+        (Either::A(true), _) | (Either::A(false), _) => (),
+        (Either::B(true, _), Either2::C) => (),
+        (Either::B(false, _), Either2::C) => (),
+        (Either::B(_, _), Either2::D) => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn or_pattern_no_diagnostic() {
+        check_diagnostics_no_bails(
+            r#"
+enum Either {A, B}
+
+fn main() {
+    match (Either::A, Either::B) {
+        (Either::A | Either::B, _) => (),
+    }
+}"#,
+        )
+    }
+
+    #[test]
+    fn mismatched_types() {
+        cov_mark::check_count!(validate_match_bailed_out, 4);
+        // Match statements with arms that don't match the
+        // expression pattern do not fire this diagnostic.
+        check_diagnostics(
+            r#"
+enum Either { A, B }
+enum Either2 { C, D }
+
+fn main() {
+    match Either::A {
+        Either2::C => (),
+        Either2::D => (),
+    }
+    match (true, false) {
+        (true, false, true) => (),
+        (true) => (),
+    }
+    match (true, false) { (true,) => {} }
+    match (0) { () => () }
+    match Unresolved::Bar { Unresolved::Baz => () }
+}
+        "#,
+        );
+    }
+
+    #[test]
+    fn mismatched_types_in_or_patterns() {
+        cov_mark::check_count!(validate_match_bailed_out, 2);
+        check_diagnostics(
+            r#"
+fn main() {
+    match false { true | () => {} }
+    match (false,) { (true | (),) => {} }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn malformed_match_arm_tuple_enum_missing_pattern() {
+        // We are testing to be sure we don't panic here when the match
+        // arm `Either::B` is missing its pattern.
+        check_diagnostics_no_bails(
+            r#"
+enum Either { A, B(u32) }
+
+fn main() {
+    match Either::A {
+        Either::A => (),
+        Either::B() => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn malformed_match_arm_extra_fields() {
+        cov_mark::check_count!(validate_match_bailed_out, 2);
+        check_diagnostics(
+            r#"
+enum A { B(isize, isize), C }
+fn main() {
+    match A::B(1, 2) {
+        A::B(_, _, _) => (),
+    }
+    match A::B(1, 2) {
+        A::C(_) => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn expr_diverges() {
+        cov_mark::check_count!(validate_match_bailed_out, 2);
+        check_diagnostics(
+            r#"
+enum Either { A, B }
+
+fn main() {
+    match loop {} {
+        Either::A => (),
+        Either::B => (),
+    }
+    match loop {} {
+        Either::A => (),
+    }
+    match loop { break Foo::A } {
+        //^^^^^^^^^^^^^^^^^^^^^ error: missing match arm
+        Either::A => (),
+    }
+    match loop { break Foo::A } {
+        Either::A => (),
+        Either::B => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn expr_partially_diverges() {
+        check_diagnostics_no_bails(
+            r#"
+enum Either<T> { A(T), B }
+
+fn foo() -> Either<!> { Either::B }
+fn main() -> u32 {
+    match foo() {
+        Either::A(val) => val,
+        Either::B => 0,
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn enum_record() {
+        check_diagnostics_no_bails(
+            r#"
+enum Either { A { foo: bool }, B }
+
+fn main() {
+    let a = Either::A { foo: true };
+    match a { }
+        //^ error: missing match arm
+    match a { Either::A { foo: true } => () }
+        //^ error: missing match arm
+    match a {
+        Either::A { } => (),
+      //^^^^^^^^^ error: missing structure fields:
+      //        | - foo
+        Either::B => (),
+    }
+    match a {
+        //^ error: missing match arm
+        Either::A { } => (),
+    } //^^^^^^^^^ error: missing structure fields:
+      //        | - foo
+
+    match a {
+        Either::A { foo: true } => (),
+        Either::A { foo: false } => (),
+        Either::B => (),
+    }
+    match a {
+        Either::A { foo: _ } => (),
+        Either::B => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn enum_record_fields_out_of_order() {
+        check_diagnostics_no_bails(
+            r#"
+enum Either {
+    A { foo: bool, bar: () },
+    B,
+}
+
+fn main() {
+    let a = Either::A { foo: true, bar: () };
+    match a {
+        //^ error: missing match arm
+        Either::A { bar: (), foo: false } => (),
+        Either::A { foo: true, bar: () } => (),
+    }
+
+    match a {
+        Either::A { bar: (), foo: false } => (),
+        Either::A { foo: true, bar: () } => (),
+        Either::B => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn enum_record_ellipsis() {
+        check_diagnostics_no_bails(
+            r#"
+enum Either {
+    A { foo: bool, bar: bool },
+    B,
+}
+
+fn main() {
+    let a = Either::B;
+    match a {
+        //^ error: missing match arm
+        Either::A { foo: true, .. } => (),
+        Either::B => (),
+    }
+    match a {
+        //^ error: missing match arm
+        Either::A { .. } => (),
+    }
+
+    match a {
+        Either::A { foo: true, .. } => (),
+        Either::A { foo: false, .. } => (),
+        Either::B => (),
+    }
+
+    match a {
+        Either::A { .. } => (),
+        Either::B => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn enum_tuple_partial_ellipsis() {
+        check_diagnostics_no_bails(
+            r#"
+enum Either {
+    A(bool, bool, bool, bool),
+    B,
+}
+
+fn main() {
+    match Either::B {
+        //^^^^^^^^^ error: missing match arm
+        Either::A(true, .., true) => (),
+        Either::A(true, .., false) => (),
+        Either::A(false, .., false) => (),
+        Either::B => (),
+    }
+    match Either::B {
+        //^^^^^^^^^ error: missing match arm
+        Either::A(true, .., true) => (),
+        Either::A(true, .., false) => (),
+        Either::A(.., true) => (),
+        Either::B => (),
+    }
+
+    match Either::B {
+        Either::A(true, .., true) => (),
+        Either::A(true, .., false) => (),
+        Either::A(false, .., true) => (),
+        Either::A(false, .., false) => (),
+        Either::B => (),
+    }
+    match Either::B {
+        Either::A(true, .., true) => (),
+        Either::A(true, .., false) => (),
+        Either::A(.., true) => (),
+        Either::A(.., false) => (),
+        Either::B => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn never() {
+        check_diagnostics_no_bails(
+            r#"
+enum Never {}
+
+fn enum_(never: Never) {
+    match never {}
+}
+fn enum_ref(never: &Never) {
+    match never {}
+        //^^^^^ error: missing match arm
+}
+fn bang(never: !) {
+    match never {}
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn unknown_type() {
+        cov_mark::check_count!(validate_match_bailed_out, 1);
+
+        check_diagnostics(
+            r#"
+enum Option<T> { Some(T), None }
+
+fn main() {
+    // `Never` is deliberately not defined so that it's an uninferred type.
+    match Option::<Never>::None {
+        None => (),
+        Some(never) => match never {},
+    }
+    match Option::<Never>::None {
+        //^^^^^^^^^^^^^^^^^^^^^ error: missing match arm
+        Option::Some(_never) => {},
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn tuple_of_bools_with_ellipsis_at_end_missing_arm() {
+        check_diagnostics_no_bails(
+            r#"
+fn main() {
+    match (false, true, false) {
+        //^^^^^^^^^^^^^^^^^^^^ error: missing match arm
+        (false, ..) => (),
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn tuple_of_bools_with_ellipsis_at_beginning_missing_arm() {
+        check_diagnostics_no_bails(
+            r#"
+fn main() {
+    match (false, true, false) {
+        //^^^^^^^^^^^^^^^^^^^^ error: missing match arm
+        (.., false) => (),
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn tuple_of_bools_with_ellipsis_in_middle_missing_arm() {
+        check_diagnostics_no_bails(
+            r#"
+fn main() {
+    match (false, true, false) {
+        //^^^^^^^^^^^^^^^^^^^^ error: missing match arm
+        (true, .., false) => (),
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn record_struct() {
+        check_diagnostics_no_bails(
+            r#"struct Foo { a: bool }
+fn main(f: Foo) {
+    match f {}
+        //^ error: missing match arm
+    match f { Foo { a: true } => () }
+        //^ error: missing match arm
+    match &f { Foo { a: true } => () }
+        //^^ error: missing match arm
+    match f { Foo { a: _ } => () }
+    match f {
+        Foo { a: true } => (),
+        Foo { a: false } => (),
+    }
+    match &f {
+        Foo { a: true } => (),
+        Foo { a: false } => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn tuple_struct() {
+        check_diagnostics_no_bails(
+            r#"struct Foo(bool);
+fn main(f: Foo) {
+    match f {}
+        //^ error: missing match arm
+    match f { Foo(true) => () }
+        //^ error: missing match arm
+    match f {
+        Foo(true) => (),
+        Foo(false) => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn unit_struct() {
+        check_diagnostics_no_bails(
+            r#"struct Foo;
+fn main(f: Foo) {
+    match f {}
+        //^ error: missing match arm
+    match f { Foo => () }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn record_struct_ellipsis() {
+        check_diagnostics_no_bails(
+            r#"struct Foo { foo: bool, bar: bool }
+fn main(f: Foo) {
+    match f { Foo { foo: true, .. } => () }
+        //^ error: missing match arm
+    match f {
+        //^ error: missing match arm
+        Foo { foo: true, .. } => (),
+        Foo { bar: false, .. } => ()
+    }
+    match f { Foo { .. } => () }
+    match f {
+        Foo { foo: true, .. } => (),
+        Foo { foo: false, .. } => ()
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn internal_or() {
+        check_diagnostics_no_bails(
+            r#"
+fn main() {
+    enum Either { A(bool), B }
+    match Either::B {
+        //^^^^^^^^^ error: missing match arm
+        Either::A(true | false) => (),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn no_panic_at_unimplemented_subpattern_type() {
+        cov_mark::check_count!(validate_match_bailed_out, 1);
+
+        check_diagnostics(
+            r#"
+struct S { a: char}
+fn main(v: S) {
+    match v { S{ a }      => {} }
+    match v { S{ a: _x }  => {} }
+    match v { S{ a: 'a' } => {} }
+    match v { S{..}       => {} }
+    match v { _           => {} }
+    match v { }
+        //^ error: missing match arm
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn binding() {
+        check_diagnostics_no_bails(
+            r#"
+fn main() {
+    match true {
+        _x @ true => {}
+        false     => {}
+    }
+    match true { _x @ true => {} }
+        //^^^^ error: missing match arm
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn binding_ref_has_correct_type() {
+        cov_mark::check_count!(validate_match_bailed_out, 1);
+
+        // Asserts `PatKind::Binding(ref _x): bool`, not &bool.
+        // If that's not true match checking will panic with "incompatible constructors"
+        // FIXME: make facilities to test this directly like `tests::check_infer(..)`
+        check_diagnostics(
+            r#"
+enum Foo { A }
+fn main() {
+    // FIXME: this should not bail out but current behavior is such as the old algorithm.
+    // ExprValidator::validate_match(..) checks types of top level patterns incorrecly.
+    match Foo::A {
+        ref _x => {}
+        Foo::A => {}
+    }
+    match (true,) {
+        (ref _x,) => {}
+        (true,) => {}
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn enum_non_exhaustive() {
+        check_diagnostics_no_bails(
+            r#"
+//- /lib.rs crate:lib
+#[non_exhaustive]
+pub enum E { A, B }
+fn _local() {
+    match E::A { _ => {} }
+    match E::A {
+        E::A => {}
+        E::B => {}
+    }
+    match E::A {
+        E::A | E::B => {}
+    }
+}
+
+//- /main.rs crate:main deps:lib
+use lib::E;
+fn main() {
+    match E::A { _ => {} }
+    match E::A {
+        //^^^^ error: missing match arm
+        E::A => {}
+        E::B => {}
+    }
+    match E::A {
+        //^^^^ error: missing match arm
+        E::A | E::B => {}
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn match_guard() {
+        check_diagnostics_no_bails(
+            r#"
+fn main() {
+    match true {
+        true if false => {}
+        true          => {}
+        false         => {}
+    }
+    match true {
+        //^^^^ error: missing match arm
+        true if false => {}
+        false         => {}
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn pattern_type_is_of_substitution() {
+        cov_mark::check!(match_check_wildcard_expanded_to_substitutions);
+        check_diagnostics_no_bails(
+            r#"
+struct Foo<T>(T);
+struct Bar;
+fn main() {
+    match Foo(Bar) {
+        _ | Foo(Bar) => {}
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn record_struct_no_such_field() {
+        cov_mark::check_count!(validate_match_bailed_out, 1);
+
+        check_diagnostics(
+            r#"
+struct Foo { }
+fn main(f: Foo) {
+    match f { Foo { bar } => () }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn match_ergonomics_issue_9095() {
+        check_diagnostics_no_bails(
+            r#"
+enum Foo<T> { A(T) }
+fn main() {
+    match &Foo::A(true) {
+        _ => {}
+        Foo::A(_) => {}
+    }
+}
+"#,
+        );
+    }
+
+    mod false_negatives {
+        //! The implementation of match checking here is a work in progress. As we roll this out, we
+        //! prefer false negatives to false positives (ideally there would be no false positives). This
+        //! test module should document known false negatives. Eventually we will have a complete
+        //! implementation of match checking and this module will be empty.
+        //!
+        //! The reasons for documenting known false negatives:
+        //!
+        //!   1. It acts as a backlog of work that can be done to improve the behavior of the system.
+        //!   2. It ensures the code doesn't panic when handling these cases.
+        use super::*;
+
+        #[test]
+        fn integers() {
+            cov_mark::check_count!(validate_match_bailed_out, 1);
+
+            // We don't currently check integer exhaustiveness.
+            check_diagnostics(
+                r#"
+fn main() {
+    match 5 {
+        10 => (),
+        11..20 => (),
+    }
+}
+"#,
+            );
+        }
+
+        #[test]
+        fn reference_patterns_at_top_level() {
+            cov_mark::check_count!(validate_match_bailed_out, 1);
+
+            check_diagnostics(
+                r#"
+fn main() {
+    match &false {
+        &true => {}
+    }
+}
+            "#,
+            );
+        }
+
+        #[test]
+        fn reference_patterns_in_fields() {
+            cov_mark::check_count!(validate_match_bailed_out, 2);
+
+            check_diagnostics(
+                r#"
+fn main() {
+    match (&false,) {
+        (true,) => {}
+    }
+    match (&false,) {
+        (&true,) => {}
+    }
+}
+            "#,
+            );
+        }
+    }
+}
diff --git a/crates/ide/src/diagnostics/fixes/wrap_tail_expr.rs b/crates/ide_diagnostics/src/handlers/missing_ok_or_some_in_tail_expr.rs
index 715a403b9..63de54570 100644
--- a/crates/ide/src/diagnostics/fixes/wrap_tail_expr.rs
+++ b/crates/ide_diagnostics/src/handlers/missing_ok_or_some_in_tail_expr.rs
@@ -1,31 +1,49 @@
-use hir::{db::AstDatabase, diagnostics::MissingOkOrSomeInTailExpr, Semantics};
-use ide_assists::{Assist, AssistResolveStrategy};
-use ide_db::{source_change::SourceChange, RootDatabase};
+use hir::db::AstDatabase;
+use ide_db::{assists::Assist, source_change::SourceChange};
 use syntax::AstNode;
 use text_edit::TextEdit;
 
-use crate::diagnostics::{fix, DiagnosticWithFixes};
-
-impl DiagnosticWithFixes for MissingOkOrSomeInTailExpr {
-    fn fixes(
-        &self,
-        sema: &Semantics<RootDatabase>,
-        _resolve: &AssistResolveStrategy,
-    ) -> Option<Vec<Assist>> {
-        let root = sema.db.parse_or_expand(self.file)?;
-        let tail_expr = self.expr.to_node(&root);
-        let tail_expr_range = tail_expr.syntax().text_range();
-        let replacement = format!("{}({})", self.required, tail_expr.syntax());
-        let edit = TextEdit::replace(tail_expr_range, replacement);
-        let source_change = SourceChange::from_text_edit(self.file.original_file(sema.db), edit);
-        let name = if self.required == "Ok" { "Wrap with Ok" } else { "Wrap with Some" };
-        Some(vec![fix("wrap_tail_expr", name, source_change, tail_expr_range)])
-    }
+use crate::{fix, Diagnostic, DiagnosticsContext};
+
+// Diagnostic: missing-ok-or-some-in-tail-expr
+//
+// This diagnostic is triggered if a block that should return `Result` returns a value not wrapped in `Ok`,
+// or if a block that should return `Option` returns a value not wrapped in `Some`.
+//
+// Example:
+//
+// ```rust
+// fn foo() -> Result<u8, ()> {
+//     10
+// }
+// ```
+pub(crate) fn missing_ok_or_some_in_tail_expr(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::MissingOkOrSomeInTailExpr,
+) -> Diagnostic {
+    Diagnostic::new(
+        "missing-ok-or-some-in-tail-expr",
+        format!("wrap return expression in {}", d.required),
+        ctx.sema.diagnostics_display_range(d.expr.clone().map(|it| it.into())).range,
+    )
+    .with_fixes(fixes(ctx, d))
+}
+
+fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::MissingOkOrSomeInTailExpr) -> Option<Vec<Assist>> {
+    let root = ctx.sema.db.parse_or_expand(d.expr.file_id)?;
+    let tail_expr = d.expr.value.to_node(&root);
+    let tail_expr_range = tail_expr.syntax().text_range();
+    let replacement = format!("{}({})", d.required, tail_expr.syntax());
+    let edit = TextEdit::replace(tail_expr_range, replacement);
+    let source_change =
+        SourceChange::from_text_edit(d.expr.file_id.original_file(ctx.sema.db), edit);
+    let name = if d.required == "Ok" { "Wrap with Ok" } else { "Wrap with Some" };
+    Some(vec![fix("wrap_tail_expr", name, source_change, tail_expr_range)])
 }
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::{check_fix, check_no_diagnostics};
+    use crate::tests::{check_diagnostics, check_fix};
 
     #[test]
     fn test_wrap_return_type_option() {
@@ -169,7 +187,7 @@ fn div(x: i32, y: i32) -> MyResult<i32> {
 
     #[test]
     fn test_wrap_return_type_not_applicable_when_expr_type_does_not_match_ok_type() {
-        check_no_diagnostics(
+        check_diagnostics(
             r#"
 //- /main.rs crate:main deps:core
 use core::result::Result::{self, Ok, Err};
@@ -189,7 +207,7 @@ pub mod option {
 
     #[test]
     fn test_wrap_return_type_not_applicable_when_return_type_is_not_result_or_option() {
-        check_no_diagnostics(
+        check_diagnostics(
             r#"
 //- /main.rs crate:main deps:core
 use core::result::Result::{self, Ok, Err};
diff --git a/crates/ide_diagnostics/src/handlers/missing_unsafe.rs b/crates/ide_diagnostics/src/handlers/missing_unsafe.rs
new file mode 100644
index 000000000..7acd9228a
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/missing_unsafe.rs
@@ -0,0 +1,101 @@
+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(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",
+        ctx.sema.diagnostics_display_range(d.expr.clone().map(|it| it.into())).range,
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::check_diagnostics;
+
+    #[test]
+    fn missing_unsafe_diagnostic_with_raw_ptr() {
+        check_diagnostics(
+            r#"
+fn main() {
+    let x = &5 as *const usize;
+    unsafe { let y = *x; }
+    let z = *x;
+}         //^^ error: this operation is unsafe and requires an unsafe function or block
+"#,
+        )
+    }
+
+    #[test]
+    fn missing_unsafe_diagnostic_with_unsafe_call() {
+        check_diagnostics(
+            r#"
+struct HasUnsafe;
+
+impl HasUnsafe {
+    unsafe fn unsafe_fn(&self) {
+        let x = &5 as *const usize;
+        let y = *x;
+    }
+}
+
+unsafe fn unsafe_fn() {
+    let x = &5 as *const usize;
+    let y = *x;
+}
+
+fn main() {
+    unsafe_fn();
+  //^^^^^^^^^^^ error: this operation is unsafe and requires an unsafe function or block
+    HasUnsafe.unsafe_fn();
+  //^^^^^^^^^^^^^^^^^^^^^ error: this operation is unsafe and requires an unsafe function or block
+    unsafe {
+        unsafe_fn();
+        HasUnsafe.unsafe_fn();
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn missing_unsafe_diagnostic_with_static_mut() {
+        check_diagnostics(
+            r#"
+struct Ty {
+    a: u8,
+}
+
+static mut STATIC_MUT: Ty = Ty { a: 0 };
+
+fn main() {
+    let x = STATIC_MUT.a;
+          //^^^^^^^^^^ error: this operation is unsafe and requires an unsafe function or block
+    unsafe {
+        let x = STATIC_MUT.a;
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn no_missing_unsafe_diagnostic_with_safe_intrinsic() {
+        check_diagnostics(
+            r#"
+extern "rust-intrinsic" {
+    pub fn bitreverse(x: u32) -> u32; // Safe intrinsic
+    pub fn floorf32(x: f32) -> f32; // Unsafe intrinsic
+}
+
+fn main() {
+    let _ = bitreverse(12);
+    let _ = floorf32(12.0);
+          //^^^^^^^^^^^^^^ error: this operation is unsafe and requires an unsafe function or block
+}
+"#,
+        );
+    }
+}
diff --git a/crates/ide/src/diagnostics/fixes/create_field.rs b/crates/ide_diagnostics/src/handlers/no_such_field.rs
index a5f457dce..92e8867f4 100644
--- a/crates/ide/src/diagnostics/fixes/create_field.rs
+++ b/crates/ide_diagnostics/src/handlers/no_such_field.rs
@@ -1,4 +1,4 @@
-use hir::{db::AstDatabase, diagnostics::NoSuchField, HasSource, HirDisplay, Semantics};
+use hir::{db::AstDatabase, HasSource, HirDisplay, Semantics};
 use ide_db::{base_db::FileId, source_change::SourceChange, RootDatabase};
 use syntax::{
     ast::{self, edit::IndentLevel, make},
@@ -6,23 +6,27 @@ use syntax::{
 };
 use text_edit::TextEdit;
 
-use crate::{
-    diagnostics::{fix, DiagnosticWithFixes},
-    Assist, AssistResolveStrategy,
-};
-impl DiagnosticWithFixes for NoSuchField {
-    fn fixes(
-        &self,
-        sema: &Semantics<RootDatabase>,
-        _resolve: &AssistResolveStrategy,
-    ) -> Option<Vec<Assist>> {
-        let root = sema.db.parse_or_expand(self.file)?;
-        missing_record_expr_field_fixes(
-            &sema,
-            self.file.original_file(sema.db),
-            &self.field.to_node(&root),
-        )
-    }
+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(crate) fn no_such_field(ctx: &DiagnosticsContext<'_>, d: &hir::NoSuchField) -> Diagnostic {
+    Diagnostic::new(
+        "no-such-field",
+        "no such field",
+        ctx.sema.diagnostics_display_range(d.field.clone().map(|it| it.into())).range,
+    )
+    .with_fixes(fixes(ctx, d))
+}
+
+fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::NoSuchField) -> Option<Vec<Assist>> {
+    let root = ctx.sema.db.parse_or_expand(d.field.file_id)?;
+    missing_record_expr_field_fixes(
+        &ctx.sema,
+        d.field.file_id.original_file(ctx.sema.db),
+        &d.field.value.to_node(&root),
+    )
 }
 
 fn missing_record_expr_field_fixes(
@@ -105,7 +109,130 @@ fn missing_record_expr_field_fixes(
 
 #[cfg(test)]
 mod tests {
-    use crate::diagnostics::tests::check_fix;
+    use crate::tests::{check_diagnostics, check_fix};
+
+    #[test]
+    fn no_such_field_diagnostics() {
+        check_diagnostics(
+            r#"
+struct S { foo: i32, bar: () }
+impl S {
+    fn new() -> S {
+        S {
+      //^ 💡 error: missing structure fields:
+      //|    - bar
+            foo: 92,
+            baz: 62,
+          //^^^^^^^ 💡 error: no such field
+        }
+    }
+}
+"#,
+        );
+    }
+    #[test]
+    fn no_such_field_with_feature_flag_diagnostics() {
+        check_diagnostics(
+            r#"
+//- /lib.rs crate:foo cfg:feature=foo
+struct MyStruct {
+    my_val: usize,
+    #[cfg(feature = "foo")]
+    bar: bool,
+}
+
+impl MyStruct {
+    #[cfg(feature = "foo")]
+    pub(crate) fn new(my_val: usize, bar: bool) -> Self {
+        Self { my_val, bar }
+    }
+    #[cfg(not(feature = "foo"))]
+    pub(crate) fn new(my_val: usize, _bar: bool) -> Self {
+        Self { my_val }
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn no_such_field_enum_with_feature_flag_diagnostics() {
+        check_diagnostics(
+            r#"
+//- /lib.rs crate:foo cfg:feature=foo
+enum Foo {
+    #[cfg(not(feature = "foo"))]
+    Buz,
+    #[cfg(feature = "foo")]
+    Bar,
+    Baz
+}
+
+fn test_fn(f: Foo) {
+    match f {
+        Foo::Bar => {},
+        Foo::Baz => {},
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn no_such_field_with_feature_flag_diagnostics_on_struct_lit() {
+        check_diagnostics(
+            r#"
+//- /lib.rs crate:foo cfg:feature=foo
+struct S {
+    #[cfg(feature = "foo")]
+    foo: u32,
+    #[cfg(not(feature = "foo"))]
+    bar: u32,
+}
+
+impl S {
+    #[cfg(feature = "foo")]
+    fn new(foo: u32) -> Self {
+        Self { foo }
+    }
+    #[cfg(not(feature = "foo"))]
+    fn new(bar: u32) -> Self {
+        Self { bar }
+    }
+    fn new2(bar: u32) -> Self {
+        #[cfg(feature = "foo")]
+        { Self { foo: bar } }
+        #[cfg(not(feature = "foo"))]
+        { Self { bar } }
+    }
+    fn new2(val: u32) -> Self {
+        Self {
+            #[cfg(feature = "foo")]
+            foo: val,
+            #[cfg(not(feature = "foo"))]
+            bar: val,
+        }
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn no_such_field_with_type_macro() {
+        check_diagnostics(
+            r#"
+macro_rules! Type { () => { u32 }; }
+struct Foo { bar: Type![] }
+
+impl Foo {
+    fn new() -> Self {
+        Foo { bar: 0 }
+    }
+}
+"#,
+        );
+    }
 
     #[test]
     fn test_add_field_from_usage() {
diff --git a/crates/ide_diagnostics/src/handlers/remove_this_semicolon.rs b/crates/ide_diagnostics/src/handlers/remove_this_semicolon.rs
new file mode 100644
index 000000000..4e639f214
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/remove_this_semicolon.rs
@@ -0,0 +1,61 @@
+use hir::db::AstDatabase;
+use ide_db::source_change::SourceChange;
+use syntax::{ast, AstNode};
+use text_edit::TextEdit;
+
+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(crate) fn remove_this_semicolon(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::RemoveThisSemicolon,
+) -> Diagnostic {
+    Diagnostic::new(
+        "remove-this-semicolon",
+        "remove this semicolon",
+        ctx.sema.diagnostics_display_range(d.expr.clone().map(|it| it.into())).range,
+    )
+    .with_fixes(fixes(ctx, d))
+}
+
+fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::RemoveThisSemicolon) -> Option<Vec<Assist>> {
+    let root = ctx.sema.db.parse_or_expand(d.expr.file_id)?;
+
+    let semicolon = d
+        .expr
+        .value
+        .to_node(&root)
+        .syntax()
+        .parent()
+        .and_then(ast::ExprStmt::cast)
+        .and_then(|expr| expr.semicolon_token())?
+        .text_range();
+
+    let edit = TextEdit::delete(semicolon);
+    let source_change =
+        SourceChange::from_text_edit(d.expr.file_id.original_file(ctx.sema.db), edit);
+
+    Some(vec![fix("remove_semicolon", "Remove this semicolon", source_change, semicolon)])
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_diagnostics, check_fix};
+
+    #[test]
+    fn missing_semicolon() {
+        check_diagnostics(
+            r#"
+fn test() -> i32 { 123; }
+                 //^^^ 💡 error: remove this semicolon
+"#,
+        );
+    }
+
+    #[test]
+    fn remove_semicolon() {
+        check_fix(r#"fn f() -> i32 { 92$0; }"#, r#"fn f() -> i32 { 92 }"#);
+    }
+}
diff --git a/crates/ide_diagnostics/src/handlers/replace_filter_map_next_with_find_map.rs b/crates/ide_diagnostics/src/handlers/replace_filter_map_next_with_find_map.rs
new file mode 100644
index 000000000..cd87a10bb
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/replace_filter_map_next_with_find_map.rs
@@ -0,0 +1,179 @@
+use hir::{db::AstDatabase, InFile};
+use ide_db::source_change::SourceChange;
+use syntax::{
+    ast::{self, ArgListOwner},
+    AstNode, TextRange,
+};
+use text_edit::TextEdit;
+
+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(crate) fn replace_filter_map_next_with_find_map(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::ReplaceFilterMapNextWithFindMap,
+) -> Diagnostic {
+    Diagnostic::new(
+        "replace-filter-map-next-with-find-map",
+        "replace filter_map(..).next() with find_map(..)",
+        ctx.sema.diagnostics_display_range(InFile::new(d.file, d.next_expr.clone().into())).range,
+    )
+    .severity(Severity::WeakWarning)
+    .with_fixes(fixes(ctx, d))
+}
+
+fn fixes(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::ReplaceFilterMapNextWithFindMap,
+) -> Option<Vec<Assist>> {
+    let root = ctx.sema.db.parse_or_expand(d.file)?;
+    let next_expr = d.next_expr.to_node(&root);
+    let next_call = ast::MethodCallExpr::cast(next_expr.syntax().clone())?;
+
+    let filter_map_call = ast::MethodCallExpr::cast(next_call.receiver()?.syntax().clone())?;
+    let filter_map_name_range = filter_map_call.name_ref()?.ident_token()?.text_range();
+    let filter_map_args = filter_map_call.arg_list()?;
+
+    let range_to_replace =
+        TextRange::new(filter_map_name_range.start(), next_expr.syntax().text_range().end());
+    let replacement = format!("find_map{}", filter_map_args.syntax().text());
+    let trigger_range = next_expr.syntax().text_range();
+
+    let edit = TextEdit::replace(range_to_replace, replacement);
+
+    let source_change = SourceChange::from_text_edit(d.file.original_file(ctx.sema.db), edit);
+
+    Some(vec![fix(
+        "replace_with_find_map",
+        "Replace filter_map(..).next() with find_map()",
+        source_change,
+        trigger_range,
+    )])
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::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::tests::check_diagnostics(&format!("{}{}{}", prefix, ra_fixture, suffix))
+    }
+
+    #[test]
+    fn replace_filter_map_next_with_find_map2() {
+        check_diagnostics(
+            r#"
+    fn foo() {
+        let m = [1, 2, 3].iter().filter_map(|x| Some(92)).next();
+    }         //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 💡 weak: replace filter_map(..).next() with find_map(..)
+"#,
+        );
+    }
+
+    #[test]
+    fn replace_filter_map_next_with_find_map_no_diagnostic_without_next() {
+        check_diagnostics(
+            r#"
+fn foo() {
+    let m = [1, 2, 3]
+        .iter()
+        .filter_map(|x| Some(92))
+        .len();
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn replace_filter_map_next_with_find_map_no_diagnostic_with_intervening_methods() {
+        check_diagnostics(
+            r#"
+fn foo() {
+    let m = [1, 2, 3]
+        .iter()
+        .filter_map(|x| Some(92))
+        .map(|x| x + 2)
+        .len();
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn replace_filter_map_next_with_find_map_no_diagnostic_if_not_in_chain() {
+        check_diagnostics(
+            r#"
+fn foo() {
+    let m = [1, 2, 3]
+        .iter()
+        .filter_map(|x| Some(92));
+    let n = m.next();
+}
+"#,
+        );
+    }
+
+    #[test]
+    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};
+fn foo() {
+    let m = [1, 2, 3].iter().$0filter_map(|x| Some(92)).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 }
+    }
+}
+"#,
+            r#"
+use core::iter::Iterator;
+use core::option::Option::{self, Some, None};
+fn foo() {
+    let m = [1, 2, 3].iter().find_map(|x| Some(92));
+}
+"#,
+        )
+    }
+}
diff --git a/crates/ide_diagnostics/src/handlers/unimplemented_builtin_macro.rs b/crates/ide_diagnostics/src/handlers/unimplemented_builtin_macro.rs
new file mode 100644
index 000000000..e879de75c
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/unimplemented_builtin_macro.rs
@@ -0,0 +1,16 @@
+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(crate) fn unimplemented_builtin_macro(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::UnimplementedBuiltinMacro,
+) -> Diagnostic {
+    Diagnostic::new(
+        "unimplemented-builtin-macro",
+        "unimplemented built-in macro".to_string(),
+        ctx.sema.diagnostics_display_range(d.node.clone()).range,
+    )
+    .severity(Severity::WeakWarning)
+}
diff --git a/crates/ide_diagnostics/src/handlers/unlinked_file.rs b/crates/ide_diagnostics/src/handlers/unlinked_file.rs
new file mode 100644
index 000000000..8e601fa48
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/unlinked_file.rs
@@ -0,0 +1,298 @@
+//! Diagnostic emitted for files that aren't part of any crate.
+
+use hir::db::DefDatabase;
+use ide_db::{
+    base_db::{FileId, FileLoader, SourceDatabase, SourceDatabaseExt},
+    source_change::SourceChange,
+    RootDatabase,
+};
+use syntax::{
+    ast::{self, ModuleItemOwner, NameOwner},
+    AstNode, TextRange, TextSize,
+};
+use text_edit::TextEdit;
+
+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(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(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);
+
+    acc.push(
+        Diagnostic::new("unlinked-file", "file not included in module tree", range)
+            .with_fixes(fixes(ctx, file_id)),
+    );
+}
+
+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(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:
+    // - `mod.rs` in the same folder
+    //   - we also check `main.rs` and `lib.rs`
+    // - `$dir.rs` in the parent folder, where `$dir` is the directory containing `self.file_id`
+    let parent = our_path.parent()?;
+    let mut paths = vec![parent.join("mod.rs")?, parent.join("lib.rs")?, parent.join("main.rs")?];
+
+    // `submod/bla.rs` -> `submod.rs`
+    if let Some(newmod) = (|| {
+        let name = parent.name_and_extension()?.0;
+        parent.parent()?.join(&format!("{}.rs", name))
+    })() {
+        paths.push(newmod);
+    }
+
+    for path in &paths {
+        if let Some(parent_id) = source_root.file_for_path(path) {
+            for krate in ctx.sema.db.relevant_crates(*parent_id).iter() {
+                let crate_def_map = ctx.sema.db.crate_def_map(*krate);
+                for (_, module) in crate_def_map.modules() {
+                    if module.origin.is_inline() {
+                        // We don't handle inline `mod parent {}`s, they use different paths.
+                        continue;
+                    }
+
+                    if module.origin.file_id() == Some(*parent_id) {
+                        return make_fixes(ctx.sema.db, *parent_id, module_name, file_id);
+                    }
+                }
+            }
+        }
+    }
+
+    None
+}
+
+fn make_fixes(
+    db: &RootDatabase,
+    parent_file_id: FileId,
+    new_mod_name: &str,
+    added_file_id: FileId,
+) -> Option<Vec<Assist>> {
+    fn is_outline_mod(item: &ast::Item) -> bool {
+        matches!(item, ast::Item::Module(m) if m.item_list().is_none())
+    }
+
+    let mod_decl = format!("mod {};", new_mod_name);
+    let pub_mod_decl = format!("pub mod {};", new_mod_name);
+
+    let ast: ast::SourceFile = db.parse(parent_file_id).tree();
+
+    let mut mod_decl_builder = TextEdit::builder();
+    let mut pub_mod_decl_builder = TextEdit::builder();
+
+    // If there's an existing `mod m;` statement matching the new one, don't emit a fix (it's
+    // probably `#[cfg]`d out).
+    for item in ast.items() {
+        if let ast::Item::Module(m) = item {
+            if let Some(name) = m.name() {
+                if m.item_list().is_none() && name.to_string() == new_mod_name {
+                    cov_mark::hit!(unlinked_file_skip_fix_when_mod_already_exists);
+                    return None;
+                }
+            }
+        }
+    }
+
+    // If there are existing `mod m;` items, append after them (after the first group of them, rather).
+    match ast
+        .items()
+        .skip_while(|item| !is_outline_mod(item))
+        .take_while(|item| is_outline_mod(item))
+        .last()
+    {
+        Some(last) => {
+            cov_mark::hit!(unlinked_file_append_to_existing_mods);
+            let offset = last.syntax().text_range().end();
+            mod_decl_builder.insert(offset, format!("\n{}", mod_decl));
+            pub_mod_decl_builder.insert(offset, format!("\n{}", pub_mod_decl));
+        }
+        None => {
+            // Prepend before the first item in the file.
+            match ast.items().next() {
+                Some(item) => {
+                    cov_mark::hit!(unlinked_file_prepend_before_first_item);
+                    let offset = item.syntax().text_range().start();
+                    mod_decl_builder.insert(offset, format!("{}\n\n", mod_decl));
+                    pub_mod_decl_builder.insert(offset, format!("{}\n\n", pub_mod_decl));
+                }
+                None => {
+                    // No items in the file, so just append at the end.
+                    cov_mark::hit!(unlinked_file_empty_file);
+                    let offset = ast.syntax().text_range().end();
+                    mod_decl_builder.insert(offset, format!("{}\n", mod_decl));
+                    pub_mod_decl_builder.insert(offset, format!("{}\n", pub_mod_decl));
+                }
+            }
+        }
+    }
+
+    let trigger_range = db.parse(added_file_id).tree().syntax().text_range();
+    Some(vec![
+        fix(
+            "add_mod_declaration",
+            &format!("Insert `{}`", mod_decl),
+            SourceChange::from_text_edit(parent_file_id, mod_decl_builder.finish()),
+            trigger_range,
+        ),
+        fix(
+            "add_pub_mod_declaration",
+            &format!("Insert `{}`", pub_mod_decl),
+            SourceChange::from_text_edit(parent_file_id, pub_mod_decl_builder.finish()),
+            trigger_range,
+        ),
+    ])
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_diagnostics, check_fix, check_fixes, check_no_fix};
+
+    #[test]
+    fn unlinked_file_prepend_first_item() {
+        cov_mark::check!(unlinked_file_prepend_before_first_item);
+        // Only tests the first one for `pub mod` since the rest are the same
+        check_fixes(
+            r#"
+//- /main.rs
+fn f() {}
+//- /foo.rs
+$0
+"#,
+            vec![
+                r#"
+mod foo;
+
+fn f() {}
+"#,
+                r#"
+pub mod foo;
+
+fn f() {}
+"#,
+            ],
+        );
+    }
+
+    #[test]
+    fn unlinked_file_append_mod() {
+        cov_mark::check!(unlinked_file_append_to_existing_mods);
+        check_fix(
+            r#"
+//- /main.rs
+//! Comment on top
+
+mod preexisting;
+
+mod preexisting2;
+
+struct S;
+
+mod preexisting_bottom;)
+//- /foo.rs
+$0
+"#,
+            r#"
+//! Comment on top
+
+mod preexisting;
+
+mod preexisting2;
+mod foo;
+
+struct S;
+
+mod preexisting_bottom;)
+"#,
+        );
+    }
+
+    #[test]
+    fn unlinked_file_insert_in_empty_file() {
+        cov_mark::check!(unlinked_file_empty_file);
+        check_fix(
+            r#"
+//- /main.rs
+//- /foo.rs
+$0
+"#,
+            r#"
+mod foo;
+"#,
+        );
+    }
+
+    #[test]
+    fn unlinked_file_old_style_modrs() {
+        check_fix(
+            r#"
+//- /main.rs
+mod submod;
+//- /submod/mod.rs
+// in mod.rs
+//- /submod/foo.rs
+$0
+"#,
+            r#"
+// in mod.rs
+mod foo;
+"#,
+        );
+    }
+
+    #[test]
+    fn unlinked_file_new_style_mod() {
+        check_fix(
+            r#"
+//- /main.rs
+mod submod;
+//- /submod.rs
+//- /submod/foo.rs
+$0
+"#,
+            r#"
+mod foo;
+"#,
+        );
+    }
+
+    #[test]
+    fn unlinked_file_with_cfg_off() {
+        cov_mark::check!(unlinked_file_skip_fix_when_mod_already_exists);
+        check_no_fix(
+            r#"
+//- /main.rs
+#[cfg(never)]
+mod foo;
+
+//- /foo.rs
+$0
+"#,
+        );
+    }
+
+    #[test]
+    fn unlinked_file_with_cfg_on() {
+        check_diagnostics(
+            r#"
+//- /main.rs
+#[cfg(not(never))]
+mod foo;
+
+//- /foo.rs
+"#,
+        );
+    }
+}
diff --git a/crates/ide_diagnostics/src/handlers/unresolved_extern_crate.rs b/crates/ide_diagnostics/src/handlers/unresolved_extern_crate.rs
new file mode 100644
index 000000000..74e4a69c6
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/unresolved_extern_crate.rs
@@ -0,0 +1,49 @@
+use crate::{Diagnostic, DiagnosticsContext};
+
+// Diagnostic: unresolved-extern-crate
+//
+// This diagnostic is triggered if rust-analyzer is unable to discover referred extern crate.
+pub(crate) fn unresolved_extern_crate(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::UnresolvedExternCrate,
+) -> Diagnostic {
+    Diagnostic::new(
+        "unresolved-extern-crate",
+        "unresolved extern crate",
+        ctx.sema.diagnostics_display_range(d.decl.clone().map(|it| it.into())).range,
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::check_diagnostics;
+
+    #[test]
+    fn unresolved_extern_crate() {
+        check_diagnostics(
+            r#"
+//- /main.rs crate:main deps:core
+extern crate core;
+  extern crate doesnotexist;
+//^^^^^^^^^^^^^^^^^^^^^^^^^^ error: unresolved extern crate
+//- /lib.rs crate:core
+"#,
+        );
+    }
+
+    #[test]
+    fn extern_crate_self_as() {
+        cov_mark::check!(extern_crate_self_as);
+        check_diagnostics(
+            r#"
+//- /lib.rs
+  extern crate doesnotexist;
+//^^^^^^^^^^^^^^^^^^^^^^^^^^ error: unresolved extern crate
+// Should not error.
+extern crate self as foo;
+struct Foo;
+use foo::Foo as Bar;
+"#,
+        );
+    }
+}
diff --git a/crates/ide_diagnostics/src/handlers/unresolved_import.rs b/crates/ide_diagnostics/src/handlers/unresolved_import.rs
new file mode 100644
index 000000000..e52a88459
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/unresolved_import.rs
@@ -0,0 +1,90 @@
+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(crate) fn unresolved_import(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::UnresolvedImport,
+) -> Diagnostic {
+    Diagnostic::new(
+        "unresolved-import",
+        "unresolved import",
+        ctx.sema.diagnostics_display_range(d.decl.clone().map(|it| it.into())).range,
+    )
+    // This currently results in false positives in the following cases:
+    // - `cfg_if!`-generated code in libstd (we don't load the sysroot correctly)
+    // - `core::arch` (we don't handle `#[path = "../<path>"]` correctly)
+    // - proc macros and/or proc macro generated code
+    .experimental()
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::check_diagnostics;
+
+    #[test]
+    fn unresolved_import() {
+        check_diagnostics(
+            r#"
+use does_exist;
+use does_not_exist;
+  //^^^^^^^^^^^^^^ error: unresolved import
+
+mod does_exist {}
+"#,
+        );
+    }
+
+    #[test]
+    fn unresolved_import_in_use_tree() {
+        // Only the relevant part of a nested `use` item should be highlighted.
+        check_diagnostics(
+            r#"
+use does_exist::{Exists, DoesntExist};
+                       //^^^^^^^^^^^ error: unresolved import
+
+use {does_not_exist::*, does_exist};
+   //^^^^^^^^^^^^^^^^^ error: unresolved import
+
+use does_not_exist::{
+    a,
+  //^ error: unresolved import
+    b,
+  //^ error: unresolved import
+    c,
+  //^ error: unresolved import
+};
+
+mod does_exist {
+    pub struct Exists;
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn dedup_unresolved_import_from_unresolved_crate() {
+        check_diagnostics(
+            r#"
+//- /main.rs crate:main
+mod a {
+    extern crate doesnotexist;
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^ error: unresolved extern crate
+
+    // Should not error, since we already errored for the missing crate.
+    use doesnotexist::{self, bla, *};
+
+    use crate::doesnotexist;
+      //^^^^^^^^^^^^^^^^^^^ error: unresolved import
+}
+
+mod m {
+    use super::doesnotexist;
+      //^^^^^^^^^^^^^^^^^^^ error: unresolved import
+}
+"#,
+        );
+    }
+}
diff --git a/crates/ide_diagnostics/src/handlers/unresolved_macro_call.rs b/crates/ide_diagnostics/src/handlers/unresolved_macro_call.rs
new file mode 100644
index 000000000..f0f7725db
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/unresolved_macro_call.rs
@@ -0,0 +1,84 @@
+use hir::{db::AstDatabase, InFile};
+use syntax::{AstNode, SyntaxNodePtr};
+
+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(crate) fn unresolved_macro_call(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::UnresolvedMacroCall,
+) -> Diagnostic {
+    let last_path_segment = ctx.sema.db.parse_or_expand(d.macro_call.file_id).and_then(|root| {
+        d.macro_call
+            .value
+            .to_node(&root)
+            .path()
+            .and_then(|it| it.segment())
+            .and_then(|it| it.name_ref())
+            .map(|it| InFile::new(d.macro_call.file_id, SyntaxNodePtr::new(it.syntax())))
+    });
+    let diagnostics = last_path_segment.unwrap_or_else(|| d.macro_call.clone().map(|it| it.into()));
+
+    Diagnostic::new(
+        "unresolved-macro-call",
+        format!("unresolved macro `{}!`", d.path),
+        ctx.sema.diagnostics_display_range(diagnostics).range,
+    )
+    .experimental()
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::check_diagnostics;
+
+    #[test]
+    fn unresolved_macro_diag() {
+        check_diagnostics(
+            r#"
+fn f() {
+    m!();
+} //^ error: unresolved macro `m!`
+
+"#,
+        );
+    }
+
+    #[test]
+    fn test_unresolved_macro_range() {
+        check_diagnostics(
+            r#"
+foo::bar!(92);
+   //^^^ error: unresolved macro `foo::bar!`
+"#,
+        );
+    }
+
+    #[test]
+    fn unresolved_legacy_scope_macro() {
+        check_diagnostics(
+            r#"
+macro_rules! m { () => {} }
+
+m!(); m2!();
+    //^^ error: unresolved macro `self::m2!`
+"#,
+        );
+    }
+
+    #[test]
+    fn unresolved_module_scope_macro() {
+        check_diagnostics(
+            r#"
+mod mac {
+#[macro_export]
+macro_rules! m { () => {} } }
+
+self::m!(); self::m2!();
+                //^^ error: unresolved macro `self::m2!`
+"#,
+        );
+    }
+}
diff --git a/crates/ide/src/diagnostics/fixes/unresolved_module.rs b/crates/ide_diagnostics/src/handlers/unresolved_module.rs
index b3d0283bb..61fc43604 100644
--- a/crates/ide/src/diagnostics/fixes/unresolved_module.rs
+++ b/crates/ide_diagnostics/src/handlers/unresolved_module.rs
@@ -1,39 +1,61 @@
-use hir::{db::AstDatabase, diagnostics::UnresolvedModule, Semantics};
-use ide_assists::{Assist, AssistResolveStrategy};
-use ide_db::{base_db::AnchoredPathBuf, source_change::FileSystemEdit, RootDatabase};
+use hir::db::AstDatabase;
+use ide_db::{assists::Assist, base_db::AnchoredPathBuf, source_change::FileSystemEdit};
 use syntax::AstNode;
 
-use crate::diagnostics::{fix, DiagnosticWithFixes};
+use crate::{fix, Diagnostic, DiagnosticsContext};
 
-impl DiagnosticWithFixes for UnresolvedModule {
-    fn fixes(
-        &self,
-        sema: &Semantics<RootDatabase>,
-        _resolve: &AssistResolveStrategy,
-    ) -> Option<Vec<Assist>> {
-        let root = sema.db.parse_or_expand(self.file)?;
-        let unresolved_module = self.decl.to_node(&root);
-        Some(vec![fix(
-            "create_module",
-            "Create module",
-            FileSystemEdit::CreateFile {
-                dst: AnchoredPathBuf {
-                    anchor: self.file.original_file(sema.db),
-                    path: self.candidate.clone(),
-                },
-                initial_contents: "".to_string(),
-            }
-            .into(),
-            unresolved_module.syntax().text_range(),
-        )])
-    }
+// Diagnostic: unresolved-module
+//
+// This diagnostic is triggered if rust-analyzer is unable to discover referred module.
+pub(crate) fn unresolved_module(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::UnresolvedModule,
+) -> Diagnostic {
+    Diagnostic::new(
+        "unresolved-module",
+        "unresolved module",
+        ctx.sema.diagnostics_display_range(d.decl.clone().map(|it| it.into())).range,
+    )
+    .with_fixes(fixes(ctx, d))
+}
+
+fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::UnresolvedModule) -> Option<Vec<Assist>> {
+    let root = ctx.sema.db.parse_or_expand(d.decl.file_id)?;
+    let unresolved_module = d.decl.value.to_node(&root);
+    Some(vec![fix(
+        "create_module",
+        "Create module",
+        FileSystemEdit::CreateFile {
+            dst: AnchoredPathBuf {
+                anchor: d.decl.file_id.original_file(ctx.sema.db),
+                path: d.candidate.clone(),
+            },
+            initial_contents: "".to_string(),
+        }
+        .into(),
+        unresolved_module.syntax().text_range(),
+    )])
 }
 
 #[cfg(test)]
 mod tests {
     use expect_test::expect;
 
-    use crate::diagnostics::tests::check_expect;
+    use crate::tests::{check_diagnostics, check_expect};
+
+    #[test]
+    fn unresolved_module() {
+        check_diagnostics(
+            r#"
+//- /lib.rs
+mod foo;
+  mod bar;
+//^^^^^^^^ 💡 error: unresolved module
+mod baz {}
+//- /foo.rs
+"#,
+        );
+    }
 
     #[test]
     fn test_unresolved_module_diagnostic() {
@@ -42,9 +64,14 @@ mod tests {
             expect![[r#"
                 [
                     Diagnostic {
+                        code: DiagnosticCode(
+                            "unresolved-module",
+                        ),
                         message: "unresolved module",
                         range: 0..8,
                         severity: Error,
+                        unused: false,
+                        experimental: false,
                         fixes: Some(
                             [
                                 Assist {
@@ -75,12 +102,6 @@ mod tests {
                                 },
                             ],
                         ),
-                        unused: false,
-                        code: Some(
-                            DiagnosticCode(
-                                "unresolved-module",
-                            ),
-                        ),
                     },
                 ]
             "#]],
diff --git a/crates/ide_diagnostics/src/handlers/unresolved_proc_macro.rs b/crates/ide_diagnostics/src/handlers/unresolved_proc_macro.rs
new file mode 100644
index 000000000..fde1d1323
--- /dev/null
+++ b/crates/ide_diagnostics/src/handlers/unresolved_proc_macro.rs
@@ -0,0 +1,27 @@
+use crate::{Diagnostic, DiagnosticsContext, Severity};
+
+// Diagnostic: unresolved-proc-macro
+//
+// This diagnostic is shown when a procedural macro can not be found. This usually means that
+// procedural macro support is simply disabled (and hence is only a weak hint instead of an error),
+// but can also indicate project setup problems.
+//
+// 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(crate) fn unresolved_proc_macro(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::UnresolvedProcMacro,
+) -> Diagnostic {
+    // Use more accurate position if available.
+    let display_range = d
+        .precise_location
+        .unwrap_or_else(|| ctx.sema.diagnostics_display_range(d.node.clone()).range);
+    // FIXME: it would be nice to tell the user whether proc macros are currently disabled
+    let message = match &d.macro_name {
+        Some(name) => format!("proc macro `{}` not expanded", name),
+        None => "proc macro not expanded".to_string(),
+    };
+
+    Diagnostic::new("unresolved-proc-macro", message, display_range).severity(Severity::WeakWarning)
+}
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/ide_ssr/Cargo.toml b/crates/ide_ssr/Cargo.toml
index 5d2221ebc..727d17bac 100644
--- a/crates/ide_ssr/Cargo.toml
+++ b/crates/ide_ssr/Cargo.toml
@@ -11,7 +11,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = { version = "1.1", features = ["thread-local"] }
+cov-mark = "2.0.0-pre.1"
 rustc-hash = "1.1.0"
 itertools = "0.10.0"
 
diff --git a/crates/ide_ssr/src/matching.rs b/crates/ide_ssr/src/matching.rs
index b3072fb9f..fb92a0ccc 100644
--- a/crates/ide_ssr/src/matching.rs
+++ b/crates/ide_ssr/src/matching.rs
@@ -382,7 +382,7 @@ impl<'db, 'sema> Matcher<'db, 'sema> {
         code: Option<T>,
     ) -> Result<(), MatchFailed> {
         match (pattern, code) {
-            (Some(p), Some(c)) => self.attempt_match_node(phase, &p.syntax(), &c.syntax()),
+            (Some(p), Some(c)) => self.attempt_match_node(phase, p.syntax(), c.syntax()),
             (None, None) => Ok(()),
             (Some(p), None) => fail_match!("Pattern `{}` had nothing to match", p.syntax().text()),
             (None, Some(c)) => {
@@ -478,7 +478,7 @@ impl<'db, 'sema> Matcher<'db, 'sema> {
                                 if Some(first_token.text()) == next_pattern_token.as_deref() {
                                     if let Some(SyntaxElement::Node(p)) = pattern.next() {
                                         // We have a subtree that starts with the next token in our pattern.
-                                        self.attempt_match_token_tree(phase, &p, &n)?;
+                                        self.attempt_match_token_tree(phase, &p, n)?;
                                         break;
                                     }
                                 }
@@ -609,7 +609,7 @@ impl<'db, 'sema> Matcher<'db, 'sema> {
         expr: &ast::Expr,
     ) -> Result<usize, MatchFailed> {
         use hir::HirDisplay;
-        let code_type = self.sema.type_of_expr(&expr).ok_or_else(|| {
+        let code_type = self.sema.type_of_expr(expr).ok_or_else(|| {
             match_error!("Failed to get receiver type for `{}`", expr.syntax().text())
         })?;
         // Temporary needed to make the borrow checker happy.
diff --git a/crates/ide_ssr/src/replacing.rs b/crates/ide_ssr/src/replacing.rs
index c9ccc1961..9265af7c1 100644
--- a/crates/ide_ssr/src/replacing.rs
+++ b/crates/ide_ssr/src/replacing.rs
@@ -84,16 +84,16 @@ impl ReplacementRenderer<'_> {
     fn render_node_or_token(&mut self, node_or_token: &SyntaxElement) {
         match node_or_token {
             SyntaxElement::Token(token) => {
-                self.render_token(&token);
+                self.render_token(token);
             }
             SyntaxElement::Node(child_node) => {
-                self.render_node(&child_node);
+                self.render_node(child_node);
             }
         }
     }
 
     fn render_node(&mut self, node: &SyntaxNode) {
-        if let Some(mod_path) = self.match_info.rendered_template_paths.get(&node) {
+        if let Some(mod_path) = self.match_info.rendered_template_paths.get(node) {
             self.out.push_str(&mod_path.to_string());
             // Emit everything except for the segment's name-ref, since we already effectively
             // emitted that as part of `mod_path`.
@@ -107,12 +107,12 @@ impl ReplacementRenderer<'_> {
                 }
             }
         } else {
-            self.render_node_children(&node);
+            self.render_node_children(node);
         }
     }
 
     fn render_token(&mut self, token: &SyntaxToken) {
-        if let Some(placeholder) = self.rule.get_placeholder(&token) {
+        if let Some(placeholder) = self.rule.get_placeholder(token) {
             if let Some(placeholder_value) =
                 self.match_info.placeholder_values.get(&placeholder.ident)
             {
diff --git a/crates/ide_ssr/src/resolving.rs b/crates/ide_ssr/src/resolving.rs
index 541da4122..a66a7a4a8 100644
--- a/crates/ide_ssr/src/resolving.rs
+++ b/crates/ide_ssr/src/resolving.rs
@@ -211,7 +211,7 @@ impl<'db> ResolutionScope<'db> {
         // First try resolving the whole path. This will work for things like
         // `std::collections::HashMap`, but will fail for things like
         // `std::collections::HashMap::new`.
-        if let Some(resolution) = self.scope.speculative_resolve(&path) {
+        if let Some(resolution) = self.scope.speculative_resolve(path) {
             return Some(resolution);
         }
         // Resolution failed, try resolving the qualifier (e.g. `std::collections::HashMap` and if
diff --git a/crates/ide_ssr/src/search.rs b/crates/ide_ssr/src/search.rs
index 28cef742c..f2056919e 100644
--- a/crates/ide_ssr/src/search.rs
+++ b/crates/ide_ssr/src/search.rs
@@ -173,7 +173,7 @@ impl<'db> MatchFinder<'db> {
         if !is_search_permitted(code) {
             return;
         }
-        self.try_add_match(rule, &code, restrict_range, matches_out);
+        self.try_add_match(rule, code, restrict_range, matches_out);
         // If we've got a macro call, we already tried matching it pre-expansion, which is the only
         // way to match the whole macro, now try expanding it and matching the expansion.
         if let Some(macro_call) = ast::MacroCall::cast(code.clone()) {
diff --git a/crates/ide_ssr/src/tests.rs b/crates/ide_ssr/src/tests.rs
index 1d8565dc0..444c6b0af 100644
--- a/crates/ide_ssr/src/tests.rs
+++ b/crates/ide_ssr/src/tests.rs
@@ -75,7 +75,7 @@ pub(crate) fn single_file(code: &str) -> (ide_db::RootDatabase, FilePosition, Ve
     match range_or_offset {
         RangeOrOffset::Range(range) => {
             position = FilePosition { file_id, offset: range.start() };
-            selections = vec![FileRange { file_id, range: range }];
+            selections = vec![FileRange { file_id, range }];
         }
         RangeOrOffset::Offset(offset) => {
             position = FilePosition { file_id, offset };
@@ -129,7 +129,7 @@ fn assert_matches(pattern: &str, code: &str, expected: &[&str]) {
     let matched_strings: Vec<String> =
         match_finder.matches().flattened().matches.iter().map(|m| m.matched_text()).collect();
     if matched_strings != expected && !expected.is_empty() {
-        print_match_debug_info(&match_finder, position.file_id, &expected[0]);
+        print_match_debug_info(&match_finder, position.file_id, expected[0]);
     }
     assert_eq!(matched_strings, expected);
 }
diff --git a/crates/mbe/Cargo.toml b/crates/mbe/Cargo.toml
index 8856787c0..f3092d9aa 100644
--- a/crates/mbe/Cargo.toml
+++ b/crates/mbe/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = { version = "1.1", features = ["thread-local"] }
+cov-mark = "2.0.0-pre.1"
 rustc-hash = "1.1.0"
 smallvec = "1.2.0"
 log = "0.4.8"
diff --git a/crates/mbe/src/expander/matcher.rs b/crates/mbe/src/expander/matcher.rs
index c982eb58f..c2a9a38c9 100644
--- a/crates/mbe/src/expander/matcher.rs
+++ b/crates/mbe/src/expander/matcher.rs
@@ -1,6 +1,6 @@
 //! An NFA-based parser, which is porting from rustc mbe parsing code
 //!
-//! See https://github.com/rust-lang/rust/blob/70b18bc2cbac4712020019f5bf57c00905373205/compiler/rustc_expand/src/mbe/macro_parser.rs
+//! See <https://github.com/rust-lang/rust/blob/70b18bc2cbac4712020019f5bf57c00905373205/compiler/rustc_expand/src/mbe/macro_parser.rs>
 //! Here is a quick intro to how the parser works, copied from rustc:
 //!
 //! A 'position' is a dot in the middle of a matcher, usually represented as a
@@ -121,7 +121,7 @@ impl Match {
 
 /// Matching errors are added to the `Match`.
 pub(super) fn match_(pattern: &MetaTemplate, input: &tt::Subtree) -> Match {
-    let mut res = match_loop(pattern, &input);
+    let mut res = match_loop(pattern, input);
     res.bound_count = count(res.bindings.bindings());
     return res;
 
@@ -202,7 +202,7 @@ impl BindingsBuilder {
     }
 
     fn push_nested(&mut self, parent: &mut BindingsIdx, child: &BindingsIdx) {
-        let BindingsIdx(idx, nidx) = self.copy(&child);
+        let BindingsIdx(idx, nidx) = self.copy(child);
         self.nodes[parent.0].push(LinkNode::Node(Rc::new(BindingKind::Nested(idx, nidx))));
     }
 
@@ -221,7 +221,7 @@ impl BindingsBuilder {
 
     fn build_inner(&self, bindings: &mut Bindings, link_nodes: &[LinkNode<Rc<BindingKind>>]) {
         let mut nodes = Vec::new();
-        self.collect_nodes(&link_nodes, &mut nodes);
+        self.collect_nodes(link_nodes, &mut nodes);
 
         for cmd in nodes {
             match &**cmd {
@@ -282,7 +282,7 @@ impl BindingsBuilder {
 
         nested_refs.into_iter().for_each(|iter| {
             let mut child_bindings = Bindings::default();
-            self.build_inner(&mut child_bindings, &iter);
+            self.build_inner(&mut child_bindings, iter);
             nested.push(child_bindings)
         })
     }
@@ -417,7 +417,7 @@ fn match_loop_inner<'t>(
                     let sep_len = item.sep.as_ref().map_or(0, Separator::tt_count);
                     if item.sep.is_some() && sep_idx != sep_len {
                         let sep = item.sep.as_ref().unwrap();
-                        if src.clone().expect_separator(&sep, sep_idx) {
+                        if src.clone().expect_separator(sep, sep_idx) {
                             item.dot.next();
                             item.sep_parsed = Some(sep_idx + 1);
                             try_push!(next_items, item);
@@ -487,7 +487,7 @@ fn match_loop_inner<'t>(
                                 item.meta_result = Some((fork, match_res));
                                 try_push!(bb_items, item);
                             } else {
-                                bindings_builder.push_optional(&mut item.bindings, &name);
+                                bindings_builder.push_optional(&mut item.bindings, name);
                                 item.dot.next();
                                 cur_items.push(item);
                             }
@@ -495,7 +495,7 @@ fn match_loop_inner<'t>(
                         Some(err) => {
                             res.add_err(err);
                             if let Some(fragment) = match_res.value {
-                                bindings_builder.push_fragment(&mut item.bindings, &name, fragment);
+                                bindings_builder.push_fragment(&mut item.bindings, name, fragment);
                             }
                             item.is_error = true;
                             error_items.push(item);
@@ -504,7 +504,7 @@ fn match_loop_inner<'t>(
                 }
             }
             OpDelimited::Op(Op::Leaf(leaf)) => {
-                if let Err(err) = match_leaf(&leaf, &mut src.clone()) {
+                if let Err(err) = match_leaf(leaf, &mut src.clone()) {
                     res.add_err(err);
                     item.is_error = true;
                 } else {
@@ -640,10 +640,10 @@ fn match_loop(pattern: &MetaTemplate, src: &tt::Subtree) -> Match {
                 let (iter, match_res) = item.meta_result.take().unwrap();
                 match match_res.value {
                     Some(fragment) => {
-                        bindings_builder.push_fragment(&mut item.bindings, &name, fragment);
+                        bindings_builder.push_fragment(&mut item.bindings, name, fragment);
                     }
                     None if match_res.err.is_none() => {
-                        bindings_builder.push_optional(&mut item.bindings, &name);
+                        bindings_builder.push_optional(&mut item.bindings, name);
                     }
                     _ => {}
                 }
diff --git a/crates/mbe/src/expander/transcriber.rs b/crates/mbe/src/expander/transcriber.rs
index dd7fa97d7..49a137577 100644
--- a/crates/mbe/src/expander/transcriber.rs
+++ b/crates/mbe/src/expander/transcriber.rs
@@ -55,7 +55,7 @@ pub(super) fn transcribe(
     template: &MetaTemplate,
     bindings: &Bindings,
 ) -> ExpandResult<tt::Subtree> {
-    let mut ctx = ExpandCtx { bindings: &bindings, nesting: Vec::new() };
+    let mut ctx = ExpandCtx { bindings, nesting: Vec::new() };
     let mut arena: Vec<tt::TokenTree> = Vec::new();
     expand_subtree(&mut ctx, template, None, &mut arena)
 }
@@ -91,12 +91,12 @@ fn expand_subtree(
             Op::Leaf(tt) => arena.push(tt.clone().into()),
             Op::Subtree { tokens, delimiter } => {
                 let ExpandResult { value: tt, err: e } =
-                    expand_subtree(ctx, &tokens, *delimiter, arena);
+                    expand_subtree(ctx, tokens, *delimiter, arena);
                 err = err.or(e);
                 arena.push(tt.into());
             }
             Op::Var { name, id, .. } => {
-                let ExpandResult { value: fragment, err: e } = expand_var(ctx, &name, *id);
+                let ExpandResult { value: fragment, err: e } = expand_var(ctx, name, *id);
                 err = err.or(e);
                 push_fragment(arena, fragment);
             }
@@ -141,7 +141,7 @@ fn expand_var(ctx: &mut ExpandCtx, v: &SmolStr, id: tt::TokenId) -> ExpandResult
         .into();
         ExpandResult::ok(Fragment::Tokens(tt))
     } else {
-        ctx.bindings.get(&v, &mut ctx.nesting).map_or_else(
+        ctx.bindings.get(v, &mut ctx.nesting).map_or_else(
             |e| ExpandResult { value: Fragment::Tokens(tt::TokenTree::empty()), err: Some(e) },
             |b| ExpandResult::ok(b.clone()),
         )
diff --git a/crates/mbe/src/lib.rs b/crates/mbe/src/lib.rs
index 380a50744..8c8528aaf 100644
--- a/crates/mbe/src/lib.rs
+++ b/crates/mbe/src/lib.rs
@@ -280,8 +280,8 @@ impl Rule {
             .expect_subtree()
             .map_err(|()| ParseError::Expected("expected subtree".to_string()))?;
 
-        let lhs = MetaTemplate(parse_pattern(&lhs)?);
-        let rhs = MetaTemplate(parse_template(&rhs)?);
+        let lhs = MetaTemplate(parse_pattern(lhs)?);
+        let rhs = MetaTemplate(parse_template(rhs)?);
 
         Ok(crate::Rule { lhs, rhs })
     }
@@ -290,7 +290,7 @@ impl Rule {
 fn validate(pattern: &MetaTemplate) -> Result<(), ParseError> {
     for op in pattern.iter() {
         match op {
-            Op::Subtree { tokens, .. } => validate(&tokens)?,
+            Op::Subtree { tokens, .. } => validate(tokens)?,
             Op::Repeat { tokens: subtree, separator, .. } => {
                 // Checks that no repetition which could match an empty token
                 // https://github.com/rust-lang/rust/blob/a58b1ed44f5e06976de2bdc4d7dc81c36a96934f/src/librustc_expand/mbe/macro_rules.rs#L558
diff --git a/crates/mbe/src/parser.rs b/crates/mbe/src/parser.rs
index 04c0d3e75..deed884d2 100644
--- a/crates/mbe/src/parser.rs
+++ b/crates/mbe/src/parser.rs
@@ -42,7 +42,7 @@ impl<'a> OpDelimitedIter<'a> {
     }
 
     pub(crate) fn reset(&self) -> Self {
-        Self { inner: &self.inner, idx: 0, delimited: self.delimited }
+        Self { inner: self.inner, idx: 0, delimited: self.delimited }
     }
 }
 
@@ -126,11 +126,11 @@ impl Separator {
 }
 
 pub(crate) fn parse_template(template: &tt::Subtree) -> Result<Vec<Op>, ParseError> {
-    parse_inner(&template, Mode::Template).into_iter().collect()
+    parse_inner(template, Mode::Template).into_iter().collect()
 }
 
 pub(crate) fn parse_pattern(pattern: &tt::Subtree) -> Result<Vec<Op>, ParseError> {
-    parse_inner(&pattern, Mode::Pattern).into_iter().collect()
+    parse_inner(pattern, Mode::Pattern).into_iter().collect()
 }
 
 #[derive(Clone, Copy)]
@@ -140,7 +140,7 @@ enum Mode {
 }
 
 fn parse_inner(tt: &tt::Subtree, mode: Mode) -> Vec<Result<Op, ParseError>> {
-    let mut src = TtIter::new(&tt);
+    let mut src = TtIter::new(tt);
     std::iter::from_fn(move || {
         let first = src.next()?;
         Some(next_op(first, &mut src, mode))
@@ -171,7 +171,7 @@ fn next_op<'a>(first: &tt::TokenTree, src: &mut TtIter<'a>, mode: Mode) -> Resul
             match second {
                 tt::TokenTree::Subtree(subtree) => {
                     let (separator, kind) = parse_repeat(src)?;
-                    let tokens = parse_inner(&subtree, mode)
+                    let tokens = parse_inner(subtree, mode)
                         .into_iter()
                         .collect::<Result<Vec<Op>, ParseError>>()?;
                     Op::Repeat { tokens: MetaTemplate(tokens), separator, kind }
@@ -191,7 +191,7 @@ fn next_op<'a>(first: &tt::TokenTree, src: &mut TtIter<'a>, mode: Mode) -> Resul
                         Op::Var { name, kind, id }
                     }
                     tt::Leaf::Literal(lit) => {
-                        if is_boolean_literal(&lit) {
+                        if is_boolean_literal(lit) {
                             let name = lit.text.clone();
                             let kind = eat_fragment_kind(src, mode)?;
                             let id = lit.id;
@@ -206,7 +206,7 @@ fn next_op<'a>(first: &tt::TokenTree, src: &mut TtIter<'a>, mode: Mode) -> Resul
         tt::TokenTree::Leaf(tt) => Op::Leaf(tt.clone()),
         tt::TokenTree::Subtree(subtree) => {
             let tokens =
-                parse_inner(&subtree, mode).into_iter().collect::<Result<Vec<Op>, ParseError>>()?;
+                parse_inner(subtree, mode).into_iter().collect::<Result<Vec<Op>, ParseError>>()?;
             Op::Subtree { tokens: MetaTemplate(tokens), delimiter: subtree.delimiter }
         }
     };
diff --git a/crates/mbe/src/subtree_source.rs b/crates/mbe/src/subtree_source.rs
index bde370fdb..ee80807ad 100644
--- a/crates/mbe/src/subtree_source.rs
+++ b/crates/mbe/src/subtree_source.rs
@@ -22,7 +22,7 @@ impl<'a> SubtreeTokenSource {
     #[cfg(test)]
     pub(crate) fn text(&self) -> SmolStr {
         match self.cached.get(self.curr.1) {
-            Some(ref tt) => tt.text.clone(),
+            Some(tt) => tt.text.clone(),
             _ => SmolStr::new(""),
         }
     }
@@ -59,7 +59,7 @@ impl<'a> SubtreeTokenSource {
 
             current = match tt {
                 Some(tt::buffer::TokenTreeRef::Leaf(leaf, _)) => {
-                    cached.push(convert_leaf(&leaf));
+                    cached.push(convert_leaf(leaf));
                     cursor.bump()
                 }
                 Some(tt::buffer::TokenTreeRef::Subtree(subtree, _)) => {
@@ -114,7 +114,7 @@ impl<'a> TokenSource for SubtreeTokenSource {
     /// Is the current token a specified keyword?
     fn is_keyword(&self, kw: &str) -> bool {
         match self.cached.get(self.curr.1) {
-            Some(ref t) => t.text == *kw,
+            Some(t) => t.text == *kw,
             _ => false,
         }
     }
diff --git a/crates/mbe/src/syntax_bridge.rs b/crates/mbe/src/syntax_bridge.rs
index 978c75747..cdc22425d 100644
--- a/crates/mbe/src/syntax_bridge.rs
+++ b/crates/mbe/src/syntax_bridge.rs
@@ -633,7 +633,7 @@ impl<'a> TreeSink for TtTreeSink<'a> {
                     }
                 }
             };
-            self.buf += &text;
+            self.buf += text;
             self.text_pos += TextSize::of(text);
         }
 
diff --git a/crates/mbe/src/tests/expand.rs b/crates/mbe/src/tests/expand.rs
index 75c88687c..c788e427e 100644
--- a/crates/mbe/src/tests/expand.rs
+++ b/crates/mbe/src/tests/expand.rs
@@ -490,7 +490,7 @@ [email protected]
 
 fn to_subtree(tt: &tt::TokenTree) -> &tt::Subtree {
     if let tt::TokenTree::Subtree(subtree) = tt {
-        return &subtree;
+        return subtree;
     }
     unreachable!("It is not a subtree");
 }
diff --git a/crates/mbe/src/tt_iter.rs b/crates/mbe/src/tt_iter.rs
index bd54f2442..5a4eca7bf 100644
--- a/crates/mbe/src/tt_iter.rs
+++ b/crates/mbe/src/tt_iter.rs
@@ -115,7 +115,7 @@ impl<'a> TtIter<'a> {
             }
         }
 
-        let buffer = TokenBuffer::from_tokens(&self.inner.as_slice());
+        let buffer = TokenBuffer::from_tokens(self.inner.as_slice());
         let mut src = SubtreeTokenSource::new(&buffer);
         let mut sink = OffsetTokenSink { cursor: buffer.begin(), error: false };
 
diff --git a/crates/parser/src/grammar/expressions.rs b/crates/parser/src/grammar/expressions.rs
index 9d22e1950..686a64345 100644
--- a/crates/parser/src/grammar/expressions.rs
+++ b/crates/parser/src/grammar/expressions.rs
@@ -208,7 +208,7 @@ struct Restrictions {
 
 /// Binding powers of operators for a Pratt parser.
 ///
-/// See https://www.oilshell.org/blog/2016/11/03.html
+/// See <https://www.oilshell.org/blog/2016/11/03.html>
 #[rustfmt::skip]
 fn current_op(p: &Parser) -> (u8, SyntaxKind) {
     const NOT_AN_OP: (u8, SyntaxKind) = (0, T![@]);
diff --git a/crates/paths/src/lib.rs b/crates/paths/src/lib.rs
index f09ad37e3..48dac14c4 100644
--- a/crates/paths/src/lib.rs
+++ b/crates/paths/src/lib.rs
@@ -244,7 +244,7 @@ impl RelPath {
     }
 }
 
-/// Taken from https://github.com/rust-lang/cargo/blob/79c769c3d7b4c2cf6a93781575b7f592ef974255/src/cargo/util/paths.rs#L60-L85
+/// Taken from <https://github.com/rust-lang/cargo/blob/79c769c3d7b4c2cf6a93781575b7f592ef974255/src/cargo/util/paths.rs#L60-L85>
 fn normalize_path(path: &Path) -> PathBuf {
     let mut components = path.components().peekable();
     let mut ret = if let Some(c @ Component::Prefix(..)) = components.peek().cloned() {
diff --git a/crates/proc_macro_api/src/msg.rs b/crates/proc_macro_api/src/msg.rs
index 14eed4289..899895578 100644
--- a/crates/proc_macro_api/src/msg.rs
+++ b/crates/proc_macro_api/src/msg.rs
@@ -59,7 +59,7 @@ pub trait Message: Serialize + DeserializeOwned {
         Ok(match read_json(inp, buf)? {
             None => None,
             Some(text) => {
-                let mut deserializer = serde_json::Deserializer::from_str(&text);
+                let mut deserializer = serde_json::Deserializer::from_str(text);
                 // Note that some proc-macro generate very deep syntax tree
                 // We have to disable the current limit of serde here
                 deserializer.disable_recursion_limit();
diff --git a/crates/proc_macro_api/src/process.rs b/crates/proc_macro_api/src/process.rs
index 99d05aef3..38eac6c17 100644
--- a/crates/proc_macro_api/src/process.rs
+++ b/crates/proc_macro_api/src/process.rs
@@ -76,9 +76,7 @@ impl ProcMacroProcessSrv {
             .map_err(|_| tt::ExpansionError::Unknown("proc macro server crashed".into()))?;
 
         match res {
-            Some(Response::Error(err)) => {
-                return Err(tt::ExpansionError::ExpansionError(err.message));
-            }
+            Some(Response::Error(err)) => Err(tt::ExpansionError::ExpansionError(err.message)),
             Some(res) => Ok(res.try_into().map_err(|err| {
                 tt::ExpansionError::Unknown(format!("Fail to get response, reason : {:#?} ", err))
             })?),
diff --git a/crates/proc_macro_api/src/version.rs b/crates/proc_macro_api/src/version.rs
index 6dbac50b4..28a4ac086 100644
--- a/crates/proc_macro_api/src/version.rs
+++ b/crates/proc_macro_api/src/version.rs
@@ -95,7 +95,7 @@ fn read_section<'a>(dylib_binary: &'a [u8], section_name: &str) -> io::Result<&'
 /// * [version string bytes encoded in utf8] <- GET THIS BOI
 /// * [some more bytes that we don really care but still there] :-)
 /// Check this issue for more about the bytes layout:
-/// https://github.com/rust-analyzer/rust-analyzer/issues/6174
+/// <https://github.com/rust-analyzer/rust-analyzer/issues/6174>
 fn read_version(dylib_path: &Path) -> io::Result<String> {
     let dylib_file = File::open(dylib_path)?;
     let dylib_mmaped = unsafe { Mmap::map(&dylib_file) }?;
diff --git a/crates/proc_macro_srv/src/lib.rs b/crates/proc_macro_srv/src/lib.rs
index d4f04ee06..f54cbcd61 100644
--- a/crates/proc_macro_srv/src/lib.rs
+++ b/crates/proc_macro_srv/src/lib.rs
@@ -1,7 +1,7 @@
 //! RA Proc Macro Server
 //!
 //! This library is able to call compiled Rust custom derive dynamic libraries on arbitrary code.
-//! The general idea here is based on https://github.com/fedochet/rust-proc-macro-expander.
+//! The general idea here is based on <https://github.com/fedochet/rust-proc-macro-expander>.
 //!
 //! But we adapt it to better fit RA needs:
 //!
diff --git a/crates/proc_macro_srv/src/proc_macro/bridge/buffer.rs b/crates/proc_macro_srv/src/proc_macro/bridge/buffer.rs
index dae6ff1d1..3b2afe01f 100644
--- a/crates/proc_macro_srv/src/proc_macro/bridge/buffer.rs
+++ b/crates/proc_macro_srv/src/proc_macro/bridge/buffer.rs
@@ -1,6 +1,6 @@
 //! lib-proc-macro Buffer management for same-process client<->server communication.
 //!
-//! Copy from https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/buffer.rs
+//! Copy from <https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/buffer.rs>
 //! augmented with removing unstable features
 
 use std::io::{self, Write};
diff --git a/crates/proc_macro_srv/src/proc_macro/bridge/client.rs b/crates/proc_macro_srv/src/proc_macro/bridge/client.rs
index b036d4e20..c135cf7a2 100644
--- a/crates/proc_macro_srv/src/proc_macro/bridge/client.rs
+++ b/crates/proc_macro_srv/src/proc_macro/bridge/client.rs
@@ -1,6 +1,6 @@
 //! lib-proc-macro Client-side types.
 //!
-//! Copy from https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/client.rs
+//! Copy from <https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/client.rs>
 //! augmented with removing unstable features
 
 use super::*;
diff --git a/crates/proc_macro_srv/src/proc_macro/bridge/closure.rs b/crates/proc_macro_srv/src/proc_macro/bridge/closure.rs
index 273a97715..f5b6d897e 100644
--- a/crates/proc_macro_srv/src/proc_macro/bridge/closure.rs
+++ b/crates/proc_macro_srv/src/proc_macro/bridge/closure.rs
@@ -1,6 +1,6 @@
 //! lib-proc-macro Closure type (equivalent to `&mut dyn FnMut(A) -> R`) that's `repr(C)`.
 //!
-//! Copy from https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/closure.rs#
+//! Copy from <https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/closure.rs>
 //! augmented with removing unstable features
 
 #[repr(C)]
diff --git a/crates/proc_macro_srv/src/proc_macro/bridge/handle.rs b/crates/proc_macro_srv/src/proc_macro/bridge/handle.rs
index a2f77b5ac..d2a65d249 100644
--- a/crates/proc_macro_srv/src/proc_macro/bridge/handle.rs
+++ b/crates/proc_macro_srv/src/proc_macro/bridge/handle.rs
@@ -1,6 +1,6 @@
 //! lib-proc-macro Server-side handles and storage for per-handle data.
 //!
-//! Copy from https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/handle.rs
+//! Copy from <https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/handle.rs>
 //! augmented with removing unstable features
 
 use std::collections::{BTreeMap, HashMap};
diff --git a/crates/proc_macro_srv/src/proc_macro/bridge/mod.rs b/crates/proc_macro_srv/src/proc_macro/bridge/mod.rs
index e67902682..375396d1b 100644
--- a/crates/proc_macro_srv/src/proc_macro/bridge/mod.rs
+++ b/crates/proc_macro_srv/src/proc_macro/bridge/mod.rs
@@ -1,6 +1,6 @@
 //! lib-proc-macro Internal interface for communicating between a `proc_macro` client
 //!
-//! Copy from https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/mod.rs
+//! Copy from <https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/mod.rs>
 //! augmented with removing unstable features
 //!
 //! Internal interface for communicating between a `proc_macro` client
diff --git a/crates/proc_macro_srv/src/proc_macro/bridge/rpc.rs b/crates/proc_macro_srv/src/proc_macro/bridge/rpc.rs
index bd1e7c2fc..69928ec84 100644
--- a/crates/proc_macro_srv/src/proc_macro/bridge/rpc.rs
+++ b/crates/proc_macro_srv/src/proc_macro/bridge/rpc.rs
@@ -1,6 +1,6 @@
 //! lib-proc-macro Serialization for client-server communication.
 //!
-//! Copy from https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/rpc.rs
+//! Copy from <https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/rpc.rs>
 //! augmented with removing unstable features
 //!
 //! Serialization for client-server communication.
diff --git a/crates/proc_macro_srv/src/proc_macro/bridge/scoped_cell.rs b/crates/proc_macro_srv/src/proc_macro/bridge/scoped_cell.rs
index 6ef7ea43c..0436bc418 100644
--- a/crates/proc_macro_srv/src/proc_macro/bridge/scoped_cell.rs
+++ b/crates/proc_macro_srv/src/proc_macro/bridge/scoped_cell.rs
@@ -1,6 +1,6 @@
 //! lib-proc-macro `Cell` variant for (scoped) existential lifetimes.
 //!
-//! Copy from https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/scoped_cell.rs#L1
+//! Copy from <https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/scoped_cell.rs#L1>
 //! augmented with removing unstable features
 
 use std::cell::Cell;
diff --git a/crates/proc_macro_srv/src/proc_macro/bridge/server.rs b/crates/proc_macro_srv/src/proc_macro/bridge/server.rs
index 88fbdc078..cc9afd84b 100644
--- a/crates/proc_macro_srv/src/proc_macro/bridge/server.rs
+++ b/crates/proc_macro_srv/src/proc_macro/bridge/server.rs
@@ -1,6 +1,6 @@
 //! lib-proc-macro server-side traits
 //!
-//! Copy from https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/server.rs
+//! Copy from <https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/bridge/server.rs>
 //! augmented with removing unstable features
 
 use super::*;
diff --git a/crates/proc_macro_srv/src/proc_macro/diagnostic.rs b/crates/proc_macro_srv/src/proc_macro/diagnostic.rs
index 55d93917c..3c5b7bc01 100644
--- a/crates/proc_macro_srv/src/proc_macro/diagnostic.rs
+++ b/crates/proc_macro_srv/src/proc_macro/diagnostic.rs
@@ -1,6 +1,6 @@
 //! lib-proc-macro diagnostic
 //!
-//! Copy from https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/diagnostic.rs
+//! Copy from <https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/diagnostic.rs>
 //! augmented with removing unstable features
 
 use crate::proc_macro::Span;
@@ -91,7 +91,7 @@ impl<'a> Iterator for Children<'a> {
 impl Diagnostic {
     /// Creates a new diagnostic with the given `level` and `message`.
     pub fn new<T: Into<String>>(level: Level, message: T) -> Diagnostic {
-        Diagnostic { level: level, message: message.into(), spans: vec![], children: vec![] }
+        Diagnostic { level, message: message.into(), spans: vec![], children: vec![] }
     }
 
     /// Creates a new diagnostic with the given `level` and `message` pointing to
@@ -101,12 +101,7 @@ impl Diagnostic {
         S: MultiSpan,
         T: Into<String>,
     {
-        Diagnostic {
-            level: level,
-            message: message.into(),
-            spans: spans.into_spans(),
-            children: vec![],
-        }
+        Diagnostic { level, message: message.into(), spans: spans.into_spans(), children: vec![] }
     }
 
     diagnostic_child_methods!(span_error, error, Level::Error);
diff --git a/crates/proc_macro_srv/src/proc_macro/mod.rs b/crates/proc_macro_srv/src/proc_macro/mod.rs
index fc6e7344f..b7c1d04b5 100644
--- a/crates/proc_macro_srv/src/proc_macro/mod.rs
+++ b/crates/proc_macro_srv/src/proc_macro/mod.rs
@@ -1,6 +1,6 @@
 //! lib-proc-macro main module
 //!
-//! Copy from https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/lib.rs
+//! Copy from <https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/lib.rs>
 //! augmented with removing unstable features
 
 // NOTE(@edwin0cheng):
diff --git a/crates/proc_macro_srv/src/rustc_server.rs b/crates/proc_macro_srv/src/rustc_server.rs
index 5d765f6e2..65ca3eb6c 100644
--- a/crates/proc_macro_srv/src/rustc_server.rs
+++ b/crates/proc_macro_srv/src/rustc_server.rs
@@ -1,6 +1,6 @@
 //! Rustc proc-macro server implementation with tt
 //!
-//! Based on idea from https://github.com/fedochet/rust-proc-macro-expander
+//! Based on idea from <https://github.com/fedochet/rust-proc-macro-expander>
 //! The lib-proc-macro server backend is `TokenStream`-agnostic, such that
 //! we could provide any TokenStream implementation.
 //! The original idea from fedochet is using proc-macro2 as backend,
@@ -539,7 +539,7 @@ impl server::Literal for Rustc {
         } else {
             n.parse::<u128>().unwrap().to_string()
         };
-        return Literal { text: n.into(), id: tt::TokenId::unspecified() };
+        Literal { text: n.into(), id: tt::TokenId::unspecified() }
     }
 
     fn typed_integer(&mut self, n: &str, kind: &str) -> Self::Literal {
diff --git a/crates/profile/src/lib.rs b/crates/profile/src/lib.rs
index 7cd01a7df..5ea5039db 100644
--- a/crates/profile/src/lib.rs
+++ b/crates/profile/src/lib.rs
@@ -50,10 +50,10 @@ impl Drop for Scope {
 /// A wrapper around google_cpu_profiler.
 ///
 /// Usage:
-/// 1. Install gpref_tools (https://github.com/gperftools/gperftools), probably packaged with your Linux distro.
+/// 1. Install gpref_tools (<https://github.com/gperftools/gperftools>), probably packaged with your Linux distro.
 /// 2. Build with `cpu_profiler` feature.
 /// 3. Run the code, the *raw* output would be in the `./out.profile` file.
-/// 4. Install pprof for visualization (https://github.com/google/pprof).
+/// 4. Install pprof for visualization (<https://github.com/google/pprof>).
 /// 5. Bump sampling frequency to once per ms: `export CPUPROFILE_FREQUENCY=1000`
 /// 6. Use something like `pprof -svg target/release/rust-analyzer ./out.profile` to see the results.
 ///
@@ -75,7 +75,7 @@ impl Drop for Scope {
 ///
 /// See this diff for how to profile completions:
 ///
-/// https://github.com/rust-analyzer/rust-analyzer/pull/5306
+/// <https://github.com/rust-analyzer/rust-analyzer/pull/5306>
 #[derive(Debug)]
 pub struct CpuSpan {
     _private: (),
diff --git a/crates/profile/src/memory_usage.rs b/crates/profile/src/memory_usage.rs
index 6ef58c9c1..fbcb9e3c2 100644
--- a/crates/profile/src/memory_usage.rs
+++ b/crates/profile/src/memory_usage.rs
@@ -32,9 +32,7 @@ impl MemoryUsage {
                     allocated: Bytes(jemalloc_ctl::stats::allocated::read().unwrap() as isize),
                 }
             } else if #[cfg(all(target_os = "linux", target_env = "gnu"))] {
-                // Note: This is incredibly slow.
-                let alloc = unsafe { libc::mallinfo() }.uordblks as isize;
-                MemoryUsage { allocated: Bytes(alloc) }
+                memusage_linux()
             } else if #[cfg(windows)] {
                 // There doesn't seem to be an API for determining heap usage, so we try to
                 // approximate that by using the Commit Charge value.
@@ -58,6 +56,37 @@ impl MemoryUsage {
     }
 }
 
+#[cfg(all(target_os = "linux", target_env = "gnu", not(feature = "jemalloc")))]
+fn memusage_linux() -> MemoryUsage {
+    // Linux/glibc has 2 APIs for allocator introspection that we can use: mallinfo and mallinfo2.
+    // mallinfo uses `int` fields and cannot handle memory usage exceeding 2 GB.
+    // mallinfo2 is very recent, so its presence needs to be detected at runtime.
+    // Both are abysmally slow.
+
+    use std::ffi::CStr;
+    use std::sync::atomic::{AtomicUsize, Ordering};
+
+    static MALLINFO2: AtomicUsize = AtomicUsize::new(1);
+
+    let mut mallinfo2 = MALLINFO2.load(Ordering::Relaxed);
+    if mallinfo2 == 1 {
+        let cstr = CStr::from_bytes_with_nul(b"mallinfo2\0").unwrap();
+        mallinfo2 = unsafe { libc::dlsym(libc::RTLD_DEFAULT, cstr.as_ptr()) } as usize;
+        // NB: races don't matter here, since they'll always store the same value
+        MALLINFO2.store(mallinfo2, Ordering::Relaxed);
+    }
+
+    if mallinfo2 == 0 {
+        // mallinfo2 does not exist, use mallinfo.
+        let alloc = unsafe { libc::mallinfo() }.uordblks as isize;
+        MemoryUsage { allocated: Bytes(alloc) }
+    } else {
+        let mallinfo2: fn() -> libc::mallinfo2 = unsafe { std::mem::transmute(mallinfo2) };
+        let alloc = mallinfo2().uordblks as isize;
+        MemoryUsage { allocated: Bytes(alloc) }
+    }
+}
+
 #[derive(Default, PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Copy)]
 pub struct Bytes(isize);
 
diff --git a/crates/project_model/src/build_data.rs b/crates/project_model/src/build_data.rs
index 33a4f8168..53cb4bae7 100644
--- a/crates/project_model/src/build_data.rs
+++ b/crates/project_model/src/build_data.rs
@@ -184,7 +184,7 @@ impl WorkspaceBuildData {
 
                 // Copy-pasted from existing cargo_metadata. It seems like we
                 // should be using sered_stacker here?
-                let mut deserializer = serde_json::Deserializer::from_str(&line);
+                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()));
diff --git a/crates/project_model/src/cargo_workspace.rs b/crates/project_model/src/cargo_workspace.rs
index b8ad08364..ac079f83e 100644
--- a/crates/project_model/src/cargo_workspace.rs
+++ b/crates/project_model/src/cargo_workspace.rs
@@ -278,7 +278,7 @@ impl CargoWorkspace {
                 id, edition, name, manifest_path, version, metadata, ..
             } = meta_pkg;
             let meta = from_value::<PackageMetadata>(metadata.clone()).unwrap_or_default();
-            let is_member = ws_members.contains(&id);
+            let is_member = ws_members.contains(id);
             let edition = edition
                 .parse::<Edition>()
                 .with_context(|| format!("Failed to parse edition {}", edition))?;
diff --git a/crates/project_model/src/sysroot.rs b/crates/project_model/src/sysroot.rs
index 4e39d6dd3..a22f79c15 100644
--- a/crates/project_model/src/sysroot.rs
+++ b/crates/project_model/src/sysroot.rs
@@ -142,12 +142,12 @@ fn discover_sysroot_src_dir(
         log::debug!("RUST_SRC_PATH is set, but is invalid (no core: {:?}), ignoring", core);
     }
 
-    get_rust_src(&sysroot_path)
+    get_rust_src(sysroot_path)
         .or_else(|| {
             let mut rustup = Command::new(toolchain::rustup());
             rustup.current_dir(current_dir).args(&["component", "add", "rust-src"]);
             utf8_stdout(rustup).ok()?;
-            get_rust_src(&sysroot_path)
+            get_rust_src(sysroot_path)
         })
         .ok_or_else(|| {
             format_err!(
diff --git a/crates/project_model/src/workspace.rs b/crates/project_model/src/workspace.rs
index 84990075f..ef0f3c9e4 100644
--- a/crates/project_model/src/workspace.rs
+++ b/crates/project_model/src/workspace.rs
@@ -185,7 +185,7 @@ impl ProjectWorkspace {
 
     pub fn load_detached_files(detached_files: Vec<AbsPathBuf>) -> Result<ProjectWorkspace> {
         let sysroot = Sysroot::discover(
-            &detached_files.first().ok_or_else(|| format_err!("No detached files to load"))?,
+            detached_files.first().ok_or_else(|| format_err!("No detached files to load"))?,
         )?;
         let rustc_cfg = rustc_cfg::get(None, None);
         Ok(ProjectWorkspace::DetachedFiles { files: detached_files, sysroot, rustc_cfg })
@@ -324,7 +324,7 @@ impl ProjectWorkspace {
     pub fn collect_build_data_configs(&self, collector: &mut BuildDataCollector) {
         match self {
             ProjectWorkspace::Cargo { cargo, .. } => {
-                collector.add_config(&cargo.workspace_root(), cargo.build_data_config().clone());
+                collector.add_config(cargo.workspace_root(), cargo.build_data_config().clone());
             }
             _ => {}
         }
@@ -348,7 +348,7 @@ fn project_json_to_crate_graph(
         .crates()
         .filter_map(|(crate_id, krate)| {
             let file_path = &krate.root_module;
-            let file_id = load(&file_path)?;
+            let file_id = load(file_path)?;
             Some((crate_id, krate, file_id))
         })
         .map(|(crate_id, krate, file_id)| {
@@ -534,7 +534,7 @@ fn detached_files_to_crate_graph(
     cfg_options.extend(rustc_cfg);
 
     for detached_file in detached_files {
-        let file_id = match load(&detached_file) {
+        let file_id = match load(detached_file) {
             Some(file_id) => file_id,
             None => {
                 log::error!("Failed to load detached file {:?}", detached_file);
@@ -602,7 +602,7 @@ fn handle_rustc_crates(
                         crate_graph,
                         &rustc_workspace[pkg],
                         rustc_build_data_map.and_then(|it| it.get(&rustc_workspace[pkg].id)),
-                        &cfg_options,
+                        cfg_options,
                         proc_macro_loader,
                         file_id,
                         &rustc_workspace[tgt].name,
@@ -685,7 +685,7 @@ fn add_target_crate_root(
     let proc_macro = build_data
         .as_ref()
         .and_then(|it| it.proc_macro_dylib_path.as_ref())
-        .map(|it| proc_macro_loader(&it))
+        .map(|it| proc_macro_loader(it))
         .unwrap_or_default();
 
     let display_name = CrateDisplayName::from_canonical_name(cargo_name.to_string());
diff --git a/crates/rust-analyzer/src/cargo_target_spec.rs b/crates/rust-analyzer/src/cargo_target_spec.rs
index f4cd43448..5d8547152 100644
--- a/crates/rust-analyzer/src/cargo_target_spec.rs
+++ b/crates/rust-analyzer/src/cargo_target_spec.rs
@@ -123,7 +123,7 @@ impl CargoTargetSpec {
         let res = CargoTargetSpec {
             workspace_root: cargo_ws.workspace_root().to_path_buf(),
             cargo_toml: package_data.manifest.clone(),
-            package: cargo_ws.package_flag(&package_data),
+            package: cargo_ws.package_flag(package_data),
             target: target_data.name.clone(),
             target_kind: target_data.kind,
         };
diff --git a/crates/rust-analyzer/src/cli/load_cargo.rs b/crates/rust-analyzer/src/cli/load_cargo.rs
index 19cb1c046..b5f5519b4 100644
--- a/crates/rust-analyzer/src/cli/load_cargo.rs
+++ b/crates/rust-analyzer/src/cli/load_cargo.rs
@@ -126,7 +126,7 @@ fn load_crate_graph(
             }
         }
     }
-    let source_roots = source_root_config.partition(&vfs);
+    let source_roots = source_root_config.partition(vfs);
     analysis_change.set_roots(source_roots);
 
     analysis_change.set_crate_graph(crate_graph);
diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs
index 91a9b55a8..c4757a1cb 100644
--- a/crates/rust-analyzer/src/config.rs
+++ b/crates/rust-analyzer/src/config.rs
@@ -1064,8 +1064,8 @@ 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.rs b/crates/rust-analyzer/src/diagnostics.rs
index d4b9db362..2f63c26ce 100644
--- a/crates/rust-analyzer/src/diagnostics.rs
+++ b/crates/rust-analyzer/src/diagnostics.rs
@@ -47,7 +47,7 @@ impl DiagnosticCollection {
     ) {
         let diagnostics = self.check.entry(file_id).or_default();
         for existing_diagnostic in diagnostics.iter() {
-            if are_diagnostics_equal(&existing_diagnostic, &diagnostic) {
+            if are_diagnostics_equal(existing_diagnostic, &diagnostic) {
                 return;
             }
         }
diff --git a/crates/rust-analyzer/src/diagnostics/to_proto.rs b/crates/rust-analyzer/src/diagnostics/to_proto.rs
index 82dd0da9a..8594d923c 100644
--- a/crates/rust-analyzer/src/diagnostics/to_proto.rs
+++ b/crates/rust-analyzer/src/diagnostics/to_proto.rs
@@ -224,7 +224,7 @@ pub(crate) fn map_rust_diagnostic_to_lsp(
 
     let mut message = rd.message.clone();
     for child in &rd.children {
-        let child = map_rust_child_diagnostic(config, workspace_root, &child);
+        let child = map_rust_child_diagnostic(config, workspace_root, child);
         match child {
             MappedRustChildDiagnostic::SubDiagnostic(sub) => {
                 subdiagnostics.push(sub);
@@ -268,7 +268,7 @@ pub(crate) fn map_rust_diagnostic_to_lsp(
     primary_spans
         .iter()
         .flat_map(|primary_span| {
-            let primary_location = primary_location(config, workspace_root, &primary_span);
+            let primary_location = primary_location(config, workspace_root, primary_span);
 
             let mut message = message.clone();
             if needs_primary_span_label {
@@ -298,7 +298,7 @@ pub(crate) fn map_rust_diagnostic_to_lsp(
                 // generated that code.
                 let is_in_macro_call = i != 0;
 
-                let secondary_location = location(config, workspace_root, &span);
+                let secondary_location = location(config, workspace_root, span);
                 if secondary_location == primary_location {
                     continue;
                 }
diff --git a/crates/rust-analyzer/src/dispatch.rs b/crates/rust-analyzer/src/dispatch.rs
index 2011a4132..5991e72b5 100644
--- a/crates/rust-analyzer/src/dispatch.rs
+++ b/crates/rust-analyzer/src/dispatch.rs
@@ -104,7 +104,7 @@ impl<'a> RequestDispatcher<'a> {
 
         let res = crate::from_json(R::METHOD, req.params);
         match res {
-            Ok(params) => return Some((req.id, params)),
+            Ok(params) => Some((req.id, params)),
             Err(err) => {
                 let response = lsp_server::Response::new_err(
                     req.id,
@@ -112,7 +112,7 @@ impl<'a> RequestDispatcher<'a> {
                     err.to_string(),
                 );
                 self.global_state.respond(response);
-                return None;
+                None
             }
         }
     }
diff --git a/crates/rust-analyzer/src/global_state.rs b/crates/rust-analyzer/src/global_state.rs
index 582a89667..583900cfe 100644
--- a/crates/rust-analyzer/src/global_state.rs
+++ b/crates/rust-analyzer/src/global_state.rs
@@ -194,7 +194,7 @@ impl GlobalState {
                 change.change_file(file.file_id, text);
             }
             if has_fs_changes {
-                let roots = self.source_root_config.partition(&vfs);
+                let roots = self.source_root_config.partition(vfs);
                 change.set_roots(roots);
             }
             change
@@ -291,7 +291,7 @@ impl GlobalStateSnapshot {
     }
 
     pub(crate) fn url_file_version(&self, url: &Url) -> Option<i32> {
-        let path = from_proto::vfs_path(&url).ok()?;
+        let path = from_proto::vfs_path(url).ok()?;
         Some(self.mem_docs.get(&path)?.version)
     }
 
@@ -300,7 +300,7 @@ impl GlobalStateSnapshot {
         base.pop();
         let path = base.join(&path.path).unwrap();
         let path = path.as_path().unwrap();
-        url_from_abs_path(&path)
+        url_from_abs_path(path)
     }
 
     pub(crate) fn cargo_target_for_crate_root(
@@ -312,7 +312,7 @@ impl GlobalStateSnapshot {
         let path = path.as_path()?;
         self.workspaces.iter().find_map(|ws| match ws {
             ProjectWorkspace::Cargo { cargo, .. } => {
-                cargo.target_by_root(&path).map(|it| (cargo, it))
+                cargo.target_by_root(path).map(|it| (cargo, it))
             }
             ProjectWorkspace::Json { .. } => None,
             ProjectWorkspace::DetachedFiles { .. } => None,
@@ -323,7 +323,7 @@ impl GlobalStateSnapshot {
 pub(crate) fn file_id_to_url(vfs: &vfs::Vfs, id: FileId) -> Url {
     let path = vfs.file_path(id);
     let path = path.as_path().unwrap();
-    url_from_abs_path(&path)
+    url_from_abs_path(path)
 }
 
 pub(crate) fn url_to_file_id(vfs: &vfs::Vfs, url: &Url) -> Result<FileId> {
diff --git a/crates/rust-analyzer/src/handlers.rs b/crates/rust-analyzer/src/handlers.rs
index 40dd0da3e..ccf66294f 100644
--- a/crates/rust-analyzer/src/handlers.rs
+++ b/crates/rust-analyzer/src/handlers.rs
@@ -781,7 +781,7 @@ pub(crate) fn handle_completion_resolve(
     let resolve_data = match original_completion
         .data
         .take()
-        .map(|data| serde_json::from_value::<CompletionResolveData>(data))
+        .map(serde_json::from_value::<CompletionResolveData>)
         .transpose()?
     {
         Some(data) => data,
@@ -1229,14 +1229,13 @@ pub(crate) fn publish_diagnostics(
         .map(|d| Diagnostic {
             range: to_proto::range(&line_index, d.range),
             severity: Some(to_proto::diagnostic_severity(d.severity)),
-            code: d.code.map(|d| d.as_str().to_owned()).map(NumberOrString::String),
-            code_description: d.code.and_then(|code| {
-                lsp_types::Url::parse(&format!(
+            code: Some(NumberOrString::String(d.code.as_str().to_string())),
+            code_description: Some(lsp_types::CodeDescription {
+                href: lsp_types::Url::parse(&format!(
                     "https://rust-analyzer.github.io/manual.html#{}",
-                    code.as_str()
+                    d.code.as_str()
                 ))
-                .ok()
-                .map(|href| lsp_types::CodeDescription { href })
+                .unwrap(),
             }),
             source: Some("rust-analyzer".to_string()),
             message: d.message,
@@ -1396,7 +1395,7 @@ pub(crate) fn handle_semantic_tokens_full_delta(
 
     if let Some(prev_id) = &cached_tokens.result_id {
         if *prev_id == params.previous_result_id {
-            let delta = to_proto::semantic_token_delta(&cached_tokens, &semantic_tokens);
+            let delta = to_proto::semantic_token_delta(cached_tokens, &semantic_tokens);
             *cached_tokens = semantic_tokens;
             return Ok(Some(delta.into()));
         }
@@ -1540,7 +1539,7 @@ fn runnable_action_links(
     snap: &GlobalStateSnapshot,
     runnable: Runnable,
 ) -> Option<lsp_ext::CommandLinkGroup> {
-    let cargo_spec = CargoTargetSpec::for_file(&snap, runnable.nav.file_id).ok()?;
+    let cargo_spec = CargoTargetSpec::for_file(snap, runnable.nav.file_id).ok()?;
     let hover_config = snap.config.hover();
     if !hover_config.runnable() || should_skip_target(&runnable, cargo_spec.as_ref()) {
         return None;
@@ -1624,7 +1623,7 @@ fn run_rustfmt(
     text_document: TextDocumentIdentifier,
     range: Option<lsp_types::Range>,
 ) -> Result<Option<Vec<lsp_types::TextEdit>>> {
-    let file_id = from_proto::file_id(&snap, &text_document.uri)?;
+    let file_id = from_proto::file_id(snap, &text_document.uri)?;
     let file = snap.analysis.file_text(file_id)?;
     let crate_ids = snap.analysis.crate_for(file_id)?;
 
@@ -1671,7 +1670,7 @@ fn run_rustfmt(
                     .into());
                 }
 
-                let frange = from_proto::file_range(&snap, text_document, range)?;
+                let frange = from_proto::file_range(snap, text_document, range)?;
                 let start_line = line_index.index.line_col(frange.range.start()).line;
                 let end_line = line_index.index.line_col(frange.range.end()).line;
 
diff --git a/crates/rust-analyzer/src/lsp_utils.rs b/crates/rust-analyzer/src/lsp_utils.rs
index 8000b5490..087c26a71 100644
--- a/crates/rust-analyzer/src/lsp_utils.rs
+++ b/crates/rust-analyzer/src/lsp_utils.rs
@@ -124,7 +124,7 @@ pub(crate) fn apply_document_changes(
         match change.range {
             Some(range) => {
                 if !index_valid.covers(range.end.line) {
-                    line_index.index = Arc::new(ide::LineIndex::new(&old_text));
+                    line_index.index = Arc::new(ide::LineIndex::new(old_text));
                 }
                 index_valid = IndexValid::UpToLineExclusive(range.start.line);
                 let range = from_proto::text_range(&line_index, range);
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index 31d8ea9e7..1417d8379 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -701,7 +701,7 @@ impl GlobalState {
                     },
                 );
 
-                return Ok(());
+                Ok(())
             })?
             .on::<lsp_types::notification::DidChangeWatchedFiles>(|this, params| {
                 for change in params.changes {
@@ -740,7 +740,7 @@ impl GlobalState {
         let subscriptions = self
             .mem_docs
             .keys()
-            .map(|path| self.vfs.read().0.file_id(&path).unwrap())
+            .map(|path| self.vfs.read().0.file_id(path).unwrap())
             .collect::<Vec<_>>();
 
         log::trace!("updating notifications for {:?}", subscriptions);
diff --git a/crates/rust-analyzer/src/semantic_tokens.rs b/crates/rust-analyzer/src/semantic_tokens.rs
index db216d951..c20642231 100644
--- a/crates/rust-analyzer/src/semantic_tokens.rs
+++ b/crates/rust-analyzer/src/semantic_tokens.rs
@@ -112,7 +112,7 @@ impl ops::BitOrAssign<SemanticTokenModifier> for ModifierSet {
 
 /// Tokens are encoded relative to each other.
 ///
-/// This is a direct port of https://github.com/microsoft/vscode-languageserver-node/blob/f425af9de46a0187adb78ec8a46b9b2ce80c5412/server/src/sematicTokens.proposed.ts#L45
+/// This is a direct port of <https://github.com/microsoft/vscode-languageserver-node/blob/f425af9de46a0187adb78ec8a46b9b2ce80c5412/server/src/sematicTokens.proposed.ts#L45>
 pub(crate) struct SemanticTokensBuilder {
     id: String,
     prev_line: u32,
diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
index 7428a3043..e53cd3c7b 100644
--- a/crates/rust-analyzer/src/to_proto.rs
+++ b/crates/rust-analyzer/src/to_proto.rs
@@ -405,7 +405,7 @@ pub(crate) fn semantic_tokens(
                 text_range =
                     TextRange::new(text_range.start(), text_range.end() - TextSize::of('\n'));
             }
-            let range = range(&line_index, text_range);
+            let range = range(line_index, text_range);
             builder.push(range, token_index, modifier_bitset);
         }
     }
@@ -781,7 +781,7 @@ pub(crate) fn snippet_workspace_edit(
         document_changes.extend_from_slice(&ops);
     }
     for (file_id, edit) in source_change.source_file_edits {
-        let edit = snippet_text_document_edit(&snap, source_change.is_snippet, file_id, edit)?;
+        let edit = snippet_text_document_edit(snap, source_change.is_snippet, file_id, edit)?;
         document_changes.push(lsp_ext::SnippetDocumentChangeOperation::Edit(edit));
     }
     let mut workspace_edit = lsp_ext::SnippetWorkspaceEdit {
@@ -957,7 +957,7 @@ pub(crate) fn code_lens(
             let annotation_range = range(&line_index, annotation.range);
 
             let action = run.action();
-            let r = runnable(&snap, run)?;
+            let r = runnable(snap, run)?;
 
             let command = if debug {
                 command::debug_single(&r)
@@ -1236,12 +1236,12 @@ fn main() {
         assert_eq!(folds.len(), 4);
 
         let line_index = LineIndex {
-            index: Arc::new(ide::LineIndex::new(&text)),
+            index: Arc::new(ide::LineIndex::new(text)),
             endings: LineEndings::Unix,
             encoding: OffsetEncoding::Utf16,
         };
         let converted: Vec<lsp_types::FoldingRange> =
-            folds.into_iter().map(|it| folding_range(&text, &line_index, true, it)).collect();
+            folds.into_iter().map(|it| folding_range(text, &line_index, true, it)).collect();
 
         let expected_lines = [(0, 2), (4, 10), (5, 6), (7, 9)];
         assert_eq!(converted.len(), expected_lines.len());
diff --git a/crates/rust-analyzer/tests/slow-tests/main.rs b/crates/rust-analyzer/tests/slow-tests/main.rs
index 9e89209ea..3585132d4 100644
--- a/crates/rust-analyzer/tests/slow-tests/main.rs
+++ b/crates/rust-analyzer/tests/slow-tests/main.rs
@@ -493,7 +493,7 @@ fn preserves_dos_line_endings() {
     }
 
     let server = Project::with_fixture(
-        &"
+        "
 //- /Cargo.toml
 [package]
 name = \"foo\"
@@ -758,7 +758,7 @@ pub fn foo(_input: TokenStream) -> TokenStream {
         ```rust
         fn bar()
         ```"#]]
-    .assert_eq(&value);
+    .assert_eq(value);
 }
 
 #[test]
@@ -795,7 +795,7 @@ fn main() {}
 
 "#;
     let server =
-        Project::with_fixture(&code).tmp_dir(tmp_dir).server().wait_until_workspace_is_loaded();
+        Project::with_fixture(code).tmp_dir(tmp_dir).server().wait_until_workspace_is_loaded();
 
     //rename same level file
     server.request::<WillRenameFiles>(
diff --git a/crates/rust-analyzer/tests/slow-tests/support.rs b/crates/rust-analyzer/tests/slow-tests/support.rs
index 75e677762..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();
@@ -323,7 +325,7 @@ fn find_mismatch<'a>(expected: &'a Value, actual: &'a Value) -> Option<(&'a Valu
 
             if !l.is_empty() {
                 assert!(!r.is_empty());
-                Some((&l[0], &r[0]))
+                Some((l[0], r[0]))
             } else {
                 assert_eq!(r.len(), 0);
                 None
diff --git a/crates/stdx/src/panic_context.rs b/crates/stdx/src/panic_context.rs
index 8d51e20d3..26debf3c4 100644
--- a/crates/stdx/src/panic_context.rs
+++ b/crates/stdx/src/panic_context.rs
@@ -1,6 +1,6 @@
 //! A micro-crate to enhance panic messages with context info.
 //!
-//! FIXME: upstream to https://github.com/kriomant/panic-context ?
+//! FIXME: upstream to <https://github.com/kriomant/panic-context> ?
 
 use std::{cell::RefCell, panic, sync::Once};
 
diff --git a/crates/stdx/src/process.rs b/crates/stdx/src/process.rs
index b0fa12f76..692a2ab3d 100644
--- a/crates/stdx/src/process.rs
+++ b/crates/stdx/src/process.rs
@@ -1,7 +1,7 @@
 //! Read both stdout and stderr of child without deadlocks.
 //!
-//! https://github.com/rust-lang/cargo/blob/905af549966f23a9288e9993a85d1249a5436556/crates/cargo-util/src/read2.rs
-//! https://github.com/rust-lang/cargo/blob/58a961314437258065e23cb6316dfc121d96fb71/crates/cargo-util/src/process_builder.rs#L231
+//! <https://github.com/rust-lang/cargo/blob/905af549966f23a9288e9993a85d1249a5436556/crates/cargo-util/src/read2.rs>
+//! <https://github.com/rust-lang/cargo/blob/58a961314437258065e23cb6316dfc121d96fb71/crates/cargo-util/src/process_builder.rs#L231>
 
 use std::{
     io,
diff --git a/crates/syntax/Cargo.toml b/crates/syntax/Cargo.toml
index 2106732cd..f1525a649 100644
--- a/crates/syntax/Cargo.toml
+++ b/crates/syntax/Cargo.toml
@@ -11,7 +11,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = { version = "1.1", features = ["thread-local"] }
+cov-mark = "2.0.0-pre.1"
 itertools = "0.10.0"
 rowan = "=0.13.0-pre.6"
 rustc_lexer = { version = "721.0.0", package = "rustc-ap-rustc_lexer" }
diff --git a/crates/syntax/src/ast/edit.rs b/crates/syntax/src/ast/edit.rs
index 19107ee38..2663c0759 100644
--- a/crates/syntax/src/ast/edit.rs
+++ b/crates/syntax/src/ast/edit.rs
@@ -30,7 +30,7 @@ impl ast::UseTree {
         let suffix = if self.path().as_ref() == Some(prefix) && self.use_tree_list().is_none() {
             make::path_unqualified(make::path_segment_self())
         } else {
-            match split_path_prefix(&prefix) {
+            match split_path_prefix(prefix) {
                 Some(it) => it,
                 None => return self.clone(),
             }
@@ -95,7 +95,7 @@ impl fmt::Display for IndentLevel {
         let indent = if len <= spaces.len() {
             &spaces[..len]
         } else {
-            buf = iter::repeat(' ').take(len).collect::<String>();
+            buf = " ".repeat(len);
             &buf
         };
         fmt::Display::fmt(indent, f)
diff --git a/crates/syntax/src/ast/node_ext.rs b/crates/syntax/src/ast/node_ext.rs
index 3d27d2c1a..2bd9ad867 100644
--- a/crates/syntax/src/ast/node_ext.rs
+++ b/crates/syntax/src/ast/node_ext.rs
@@ -325,6 +325,15 @@ 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)]
diff --git a/crates/syntax/src/ast/token_ext.rs b/crates/syntax/src/ast/token_ext.rs
index 4b1e1ccee..ad52d9f54 100644
--- a/crates/syntax/src/ast/token_ext.rs
+++ b/crates/syntax/src/ast/token_ext.rs
@@ -242,7 +242,7 @@ impl ast::ByteString {
             (Ok(c), true) if char_range.len() == 1 && Some(c) == text_iter.next() => (),
             (Ok(c), true) => {
                 buf.reserve_exact(text.len());
-                buf.extend_from_slice(&text[..char_range.start].as_bytes());
+                buf.extend_from_slice(text[..char_range.start].as_bytes());
                 buf.push(c as u8);
             }
             (Err(_), _) => has_error = true,
diff --git a/crates/syntax/src/parsing.rs b/crates/syntax/src/parsing.rs
index 431ed0699..001921343 100644
--- a/crates/syntax/src/parsing.rs
+++ b/crates/syntax/src/parsing.rs
@@ -15,7 +15,7 @@ use crate::{syntax_node::GreenNode, AstNode, SyntaxError, SyntaxNode};
 pub(crate) use crate::parsing::{lexer::*, reparsing::incremental_reparse};
 
 pub(crate) fn parse_text(text: &str) -> (GreenNode, Vec<SyntaxError>) {
-    let (tokens, lexer_errors) = tokenize(&text);
+    let (tokens, lexer_errors) = tokenize(text);
 
     let mut token_source = TextTokenSource::new(text, &tokens);
     let mut tree_sink = TextTreeSink::new(text, &tokens);
@@ -33,7 +33,7 @@ pub(crate) fn parse_text_fragment<T: AstNode>(
     text: &str,
     fragment_kind: parser::FragmentKind,
 ) -> Result<T, ()> {
-    let (tokens, lexer_errors) = tokenize(&text);
+    let (tokens, lexer_errors) = tokenize(text);
     if !lexer_errors.is_empty() {
         return Err(());
     }
diff --git a/crates/syntax/src/parsing/lexer.rs b/crates/syntax/src/parsing/lexer.rs
index 7c8d0a4c4..ae4844e48 100644
--- a/crates/syntax/src/parsing/lexer.rs
+++ b/crates/syntax/src/parsing/lexer.rs
@@ -144,7 +144,7 @@ fn rustc_token_kind_to_syntax_kind(
             }
 
             rustc_lexer::TokenKind::RawIdent => IDENT,
-            rustc_lexer::TokenKind::Literal { kind, .. } => return match_literal_kind(&kind),
+            rustc_lexer::TokenKind::Literal { kind, .. } => return match_literal_kind(kind),
 
             rustc_lexer::TokenKind::Lifetime { starts_with_number: false } => LIFETIME_IDENT,
             rustc_lexer::TokenKind::Lifetime { starts_with_number: true } => {
diff --git a/crates/syntax/src/parsing/reparsing.rs b/crates/syntax/src/parsing/reparsing.rs
index 304f47b3d..186cc9e74 100644
--- a/crates/syntax/src/parsing/reparsing.rs
+++ b/crates/syntax/src/parsing/reparsing.rs
@@ -26,11 +26,11 @@ pub(crate) fn incremental_reparse(
     edit: &Indel,
     errors: Vec<SyntaxError>,
 ) -> Option<(GreenNode, Vec<SyntaxError>, TextRange)> {
-    if let Some((green, new_errors, old_range)) = reparse_token(node, &edit) {
+    if let Some((green, new_errors, old_range)) = reparse_token(node, edit) {
         return Some((green, merge_errors(errors, new_errors, old_range, edit), old_range));
     }
 
-    if let Some((green, new_errors, old_range)) = reparse_block(node, &edit) {
+    if let Some((green, new_errors, old_range)) = reparse_block(node, edit) {
         return Some((green, merge_errors(errors, new_errors, old_range, edit), old_range));
     }
     None
@@ -52,7 +52,7 @@ fn reparse_token(
                 }
             }
 
-            let mut new_text = get_text_after_edit(prev_token.clone().into(), &edit);
+            let mut new_text = get_text_after_edit(prev_token.clone().into(), edit);
             let (new_token_kind, new_err) = lex_single_syntax_kind(&new_text)?;
 
             if new_token_kind != prev_token_kind
diff --git a/crates/syntax/src/tests.rs b/crates/syntax/src/tests.rs
index 9f2426171..4961ca08d 100644
--- a/crates/syntax/src/tests.rs
+++ b/crates/syntax/src/tests.rs
@@ -69,13 +69,13 @@ fn parser_tests() {
     dir_tests(&test_data_dir(), &["parser/inline/ok", "parser/ok"], "rast", |text, path| {
         let parse = SourceFile::parse(text);
         let errors = parse.errors();
-        assert_errors_are_absent(&errors, path);
+        assert_errors_are_absent(errors, path);
         parse.debug_dump()
     });
     dir_tests(&test_data_dir(), &["parser/err", "parser/inline/err"], "rast", |text, path| {
         let parse = SourceFile::parse(text);
         let errors = parse.errors();
-        assert_errors_are_present(&errors, path);
+        assert_errors_are_present(errors, path);
         parse.debug_dump()
     });
 }
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/test_utils/src/fixture.rs b/crates/test_utils/src/fixture.rs
index d0bddf7d8..005a5c092 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
@@ -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 ac5a9509d..d55bae62a 100644
--- a/crates/test_utils/src/lib.rs
+++ b/crates/test_utils/src/lib.rs
@@ -23,7 +23,10 @@ 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";
@@ -190,10 +193,21 @@ pub fn add_cursor(text: &str, offset: TextSize) -> String {
     res
 }
 
-/// Extracts `//^ some text` annotations
+/// Extracts `//^^^ some text` annotations.
+///
+/// A run of `^^^` can be arbitrary long and points to the corresponding range
+/// in the line above.
+///
+/// The `// ^file text` syntax can be used to attach `text` to the entirety of
+/// the file.
+///
+/// Multiline string values are supported:
+///
+/// // ^^^ first line
+/// //   | second line
 pub fn extract_annotations(text: &str) -> Vec<(TextRange, String)> {
     let mut res = Vec::new();
-    let mut prev_line_start: Option<TextSize> = None;
+    let mut prev_line_start: Option<TextSize> = Some(0.into());
     let mut line_start: TextSize = 0.into();
     let mut prev_line_annotations: Vec<(TextSize, usize)> = Vec::new();
     for line in text.split_inclusive('\n') {
@@ -202,10 +216,15 @@ pub fn extract_annotations(text: &str) -> Vec<(TextRange, String)> {
             let annotation_offset = TextSize::of(&line[..idx + "//".len()]);
             for annotation in extract_line_annotations(&line[idx + "//".len()..]) {
                 match annotation {
-                    LineAnnotation::Annotation { mut range, content } => {
+                    LineAnnotation::Annotation { mut range, content, file } => {
                         range += annotation_offset;
                         this_line_annotations.push((range.end(), res.len()));
-                        res.push((range + prev_line_start.unwrap(), content))
+                        let range = if file {
+                            TextRange::up_to(TextSize::of(text))
+                        } else {
+                            range + prev_line_start.unwrap()
+                        };
+                        res.push((range, content))
                     }
                     LineAnnotation::Continuation { mut offset, content } => {
                         offset += annotation_offset;
@@ -226,11 +245,12 @@ pub fn extract_annotations(text: &str) -> Vec<(TextRange, String)> {
 
         prev_line_annotations = this_line_annotations;
     }
+
     res
 }
 
 enum LineAnnotation {
-    Annotation { range: TextRange, content: String },
+    Annotation { range: TextRange, content: String, file: bool },
     Continuation { offset: TextSize, content: String },
 }
 
@@ -251,12 +271,20 @@ fn extract_line_annotations(mut line: &str) -> Vec<LineAnnotation> {
         }
         let range = TextRange::at(offset, len.try_into().unwrap());
         let next = line[len..].find(marker).map_or(line.len(), |it| it + len);
-        let content = line[len..][..next - len].trim().to_string();
+        let mut content = &line[len..][..next - len];
+
+        let mut file = false;
+        if !continuation && content.starts_with("file") {
+            file = true;
+            content = &content["file".len()..]
+        }
+
+        let content = content.trim().to_string();
 
         let annotation = if continuation {
             LineAnnotation::Continuation { offset: range.end(), content }
         } else {
-            LineAnnotation::Annotation { range, content }
+            LineAnnotation::Annotation { range, content, file }
         };
         res.push(annotation);
 
@@ -277,16 +305,20 @@ fn main() {
     zoo + 1
 } //^^^ type:
   //  | i32
+
+// ^file
     "#,
     );
     let res = extract_annotations(&text)
         .into_iter()
         .map(|(range, ann)| (&text[range], ann))
         .collect::<Vec<_>>();
+
     assert_eq!(
-        res,
-        vec![("x", "def".into()), ("y", "def".into()), ("zoo", "type:\ni32\n".into()),]
+        res[..3],
+        [("x", "def".into()), ("y", "def".into()), ("zoo", "type:\ni32\n".into())]
     );
+    assert_eq!(res[3].0.len(), 115);
 }
 
 /// Returns `false` if slow tests should not run, otherwise returns `true` and
diff --git a/crates/test_utils/src/minicore.rs b/crates/test_utils/src/minicore.rs
new file mode 100644
index 000000000..e04ca58d2
--- /dev/null
+++ b/crates/test_utils/src/minicore.rs
@@ -0,0 +1,234 @@
+//! 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
+//!     fn:
+//!     pin:
+//!     future: pin
+//!     option:
+//!     result:
+
+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
+}
+
+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;
+    pub use self::deref::DerefMut; //:deref_mut
+                                   // endregion:deref
+
+    // 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: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
+
+pub mod prelude {
+    pub mod v1 {
+        pub use crate::{
+            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/tt/src/buffer.rs b/crates/tt/src/buffer.rs
index e0021039a..dc577700f 100644
--- a/crates/tt/src/buffer.rs
+++ b/crates/tt/src/buffer.rs
@@ -133,7 +133,7 @@ impl<'a> TokenTreeRef<'a> {
     }
 }
 
-/// A safe version of `Cursor` from `syn` crate https://github.com/dtolnay/syn/blob/6533607f91686545cb034d2838beea338d9d0742/src/buffer.rs#L125
+/// A safe version of `Cursor` from `syn` crate <https://github.com/dtolnay/syn/blob/6533607f91686545cb034d2838beea338d9d0742/src/buffer.rs#L125>
 #[derive(Copy, Clone, Debug)]
 pub struct Cursor<'a> {
     buffer: &'a TokenBuffer<'a>,
diff --git a/crates/tt/src/lib.rs b/crates/tt/src/lib.rs
index bed44d600..b51ad5d0f 100644
--- a/crates/tt/src/lib.rs
+++ b/crates/tt/src/lib.rs
@@ -88,7 +88,7 @@ pub struct Ident {
 }
 
 fn print_debug_subtree(f: &mut fmt::Formatter<'_>, subtree: &Subtree, level: usize) -> fmt::Result {
-    let align = std::iter::repeat("  ").take(level).collect::<String>();
+    let align = "  ".repeat(level);
 
     let aux = match subtree.delimiter.map(|it| (it.kind, it.id.0)) {
         None => "$".to_string(),
@@ -113,7 +113,7 @@ fn print_debug_subtree(f: &mut fmt::Formatter<'_>, subtree: &Subtree, level: usi
 }
 
 fn print_debug_token(f: &mut fmt::Formatter<'_>, tkn: &TokenTree, level: usize) -> fmt::Result {
-    let align = std::iter::repeat("  ").take(level).collect::<String>();
+    let align = "  ".repeat(level);
 
     match tkn {
         TokenTree::Leaf(leaf) => match leaf {
diff --git a/crates/vfs/src/file_set.rs b/crates/vfs/src/file_set.rs
index 0a4590c8d..0011f73c9 100644
--- a/crates/vfs/src/file_set.rs
+++ b/crates/vfs/src/file_set.rs
@@ -111,7 +111,7 @@ impl FileSetConfig {
         let mut scratch_space = Vec::new();
         let mut res = vec![FileSet::default(); self.len()];
         for (file_id, path) in vfs.iter() {
-            let root = self.classify(&path, &mut scratch_space);
+            let root = self.classify(path, &mut scratch_space);
             res[root].insert(file_id, path.clone())
         }
         res