89 files changed, 1189 insertions, 591 deletions
diff --git a/.github/workflows/release.yaml b/.github/workflows/release.yaml
index a97ed24ba..94b6aa7c4 100644
--- a/.github/workflows/release.yaml
+++ b/.github/workflows/release.yaml
@@ -94,6 +94,7 @@ jobs:
        toolchain: stable
        profile: minimal
        override: true
+        components: rust-src
    - name: Install Nodejs
      uses: actions/setup-node@v1
@@ -108,10 +109,12 @@ jobs:
      if: github.ref != 'refs/heads/release'
      run: cargo xtask dist --nightly --client 0.3.$GITHUB_RUN_NUMBER-nightly
-    - name: Nightly analysis-stats check
+    - name: Run analysis-stats on rust-analyzer
-      if: github.ref != 'refs/heads/release'
      run: target/${{ env.RA_TARGET }}/release/rust-analyzer analysis-stats .
+    - name: Run analysis-stats on rust std library
+      run: target/${{ env.RA_TARGET }}/release/rust-analyzer analysis-stats --with-deps $(rustc --print sysroot)/lib/rustlib/src/rust/library/std
    - name: Upload artifacts
      uses: actions/upload-artifact@v1
      with:
diff --git a/Cargo.lock b/Cargo.lock
index 901784bec..bf1b9e417 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -77,15 +77,15 @@ checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
 [[package]]
 name = "backtrace"
-version = "0.3.55"
+version = "0.3.56"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ef5140344c85b01f9bbb4d4b7288a8aa4b3287ccef913a14bcc78a1063623598"
+checksum = "9d117600f438b1707d4e4ae15d3595657288f8235a0eb593e80ecc98ab34e1bc"
 dependencies = [
 "addr2line",
 "cfg-if 1.0.0",
 "libc",
 "miniz_oxide",
- "object 0.22.0",
+ "object",
 "rustc-demangle",
 ]
@@ -175,9 +175,9 @@ checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 [[package]]
 name = "chalk-derive"
-version = "0.47.0"
+version = "0.50.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3f00f6342a387edc822002d36a381e117afcac9f744951ff75fbf4a218edea5c"
+checksum = "ac605cf409013573e971d7292d4bec6f5495b19d5f98fc9d8b1a12270c3888e0"
 dependencies = [
 "proc-macro2",
 "quote",
@@ -187,9 +187,9 @@ dependencies = [
 [[package]]
 name = "chalk-ir"
-version = "0.47.0"
+version = "0.50.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c686e69913591ae753e5526e73cbee39db3d9b0a92cc9078ab780cabf1c70aa9"
+checksum = "fa1dbfb3c2c8b67edb5cd981f720550e43579090574f786145731f90c5d401ff"
 dependencies = [
 "bitflags",
 "chalk-derive",
@@ -198,9 +198,9 @@ dependencies = [
 [[package]]
 name = "chalk-recursive"
-version = "0.47.0"
+version = "0.50.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "310fdcac0340dab4163b766baa8067266e3b909108d1ac1b5246c033bde63975"
+checksum = "0882e2a3ba66901717a64f8bb0655e809f800ac6abed05cb605e7a41d4bf8999"
 dependencies = [
 "chalk-derive",
 "chalk-ir",
@@ -211,9 +211,9 @@ dependencies = [
 [[package]]
 name = "chalk-solve"
-version = "0.47.0"
+version = "0.50.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c3c3252116111c3548f1164ab8d98c67c49848b3bde10dd11b650fd023e91c72"
+checksum = "0d43cce07150eac39771ff4b198537cefef744734b2218a89c682295b54cd8d0"
 dependencies = [
 "chalk-derive",
 "chalk-ir",
@@ -274,6 +274,17 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "28b9d6de7f49e22cf97ad17fc4036ece69300032f45f78f30b4a4482cdc3f4a6"
 [[package]]
+name = "countme"
+version = "2.0.0-pre.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c5716604cba7c02a846ecad3f4a3fd2d2b641faccc2a24a51efb21aff0d01f35"
+dependencies = [
+ "dashmap",
+ "once_cell",
+ "rustc-hash",
+]
+[[package]]
 name = "crc32fast"
 version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -323,7 +334,7 @@ dependencies = [
 "const_fn",
 "crossbeam-utils 0.8.1",
 "lazy_static",
- "memoffset 0.6.1",
+ "memoffset",
 "scopeguard",
 ]
@@ -350,6 +361,16 @@ dependencies = [
 ]
 [[package]]
+name = "dashmap"
+version = "4.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e77a43b28d0668df09411cb0bc9a8c2adc40f9a048afe863e05fd43251e8e39c"
+dependencies = [
+ "cfg-if 1.0.0",
+ "num_cpus",
+]
+[[package]]
 name = "dissimilar"
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -397,13 +418,13 @@ dependencies = [
 [[package]]
 name = "filetime"
-version = "0.2.13"
+version = "0.2.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0c122a393ea57648015bf06fbd3d372378992e86b9ff5a7a497b076a28c79efe"
+checksum = "1d34cfa13a63ae058bfa601fe9e313bbdb3746427c1459185464ce0fcf62e1e8"
 dependencies = [
 "cfg-if 1.0.0",
 "libc",
- "redox_syscall",
+ "redox_syscall 0.2.4",
 "winapi 0.3.9",
 ]
@@ -942,15 +963,6 @@ dependencies = [
 [[package]]
 name = "memoffset"
-version = "0.5.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "043175f069eda7b85febe4a74abbaeff828d9f8b448515d3151a14a3542811aa"
-dependencies = [
- "autocfg",
-]
-[[package]]
-name = "memoffset"
 version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "157b4208e3059a8f9e78d559edc658e13df41410cb3ae03979c83130067fdd87"
@@ -1082,12 +1094,6 @@ dependencies = [
 [[package]]
 name = "object"
-version = "0.22.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8d3b63360ec3cb337817c2dbd47ab4a0f170d285d8e5a2064600f3def1402397"
-[[package]]
-name = "object"
 version = "0.23.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a9a7ab5d64814df0fe4a4b5ead45ed6c5f181ee3ff04ba344313a6c80446c5d4"
@@ -1124,7 +1130,7 @@ dependencies = [
 "cfg-if 1.0.0",
 "instant",
 "libc",
- "redox_syscall",
+ "redox_syscall 0.1.57",
 "smallvec",
 "winapi 0.3.9",
 ]
@@ -1205,9 +1211,9 @@ dependencies = [
 [[package]]
 name = "pico-args"
-version = "0.3.4"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "28b9b4df73455c861d7cbf8be42f01d3b373ed7f02e378d55fa84eafc6f638b1"
+checksum = "d70072c20945e1ab871c472a285fc772aefd4f5407723c206242f2c6f94595d6"
 [[package]]
 name = "pin-project-lite"
@@ -1251,7 +1257,7 @@ dependencies = [
 "libloading",
 "mbe",
 "memmap",
- "object 0.23.0",
+ "object",
 "proc_macro_api",
 "proc_macro_test",
 "serde_derive",
@@ -1269,6 +1275,7 @@ name = "profile"
 version = "0.0.0"
 dependencies = [
 "cfg-if 1.0.0",
+ "countme",
 "jemalloc-ctl",
 "la-arena",
 "libc",
@@ -1358,6 +1365,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "41cc0f7e4d5d4544e8861606a285bb08d3e70712ccc7d2b84d7c0ccfaf4b05ce"
 [[package]]
+name = "redox_syscall"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05ec8ca9416c5ea37062b502703cd7fcb207736bc294f6e0cf367ac6fc234570"
+dependencies = [
+ "bitflags",
+]
+[[package]]
 name = "regex"
 version = "1.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1384,15 +1400,15 @@ checksum = "b5eb417147ba9860a96cfe72a0b93bf88fee1744b5636ec99ab20c1aa9376581"
 [[package]]
 name = "rowan"
-version = "0.10.6"
+version = "0.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8a0734142c18710f7214dc21908e2f054e973b908dbb1a602a3e6691615aaaae"
+checksum = "24c2d78254049413f9d73495f883e7fa0b7a7d4b88468cd72a3bbbd0ad585cd1"
 dependencies = [
+ "countme",
 "hashbrown",
+ "memoffset",
 "rustc-hash",
- "smol_str",
 "text-size",
- "triomphe",
 ]
 [[package]]
@@ -1448,9 +1464,9 @@ dependencies = [
 [[package]]
 name = "rustc-ap-rustc_lexer"
-version = "697.0.0"
+version = "700.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "67adbe260a0a11910624d6d28c0304fcf7b063e666682111005c83b09f73429d"
+checksum = "5ed36784376b69c941d7aa36e960a52ac712e2663960357121a4d9f2cc58e225"
 dependencies = [
 "unicode-xid",
 ]
@@ -1544,18 +1560,18 @@ dependencies = [
 [[package]]
 name = "serde"
-version = "1.0.119"
+version = "1.0.120"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9bdd36f49e35b61d49efd8aa7fc068fd295961fd2286d0b2ee9a4c7a14e99cc3"
+checksum = "166b2349061381baf54a58e4b13c89369feb0ef2eaa57198899e2312aac30aab"
 dependencies = [
 "serde_derive",
 ]
 [[package]]
 name = "serde_derive"
-version = "1.0.119"
+version = "1.0.120"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "552954ce79a059ddd5fd68c271592374bd15cab2274970380c000118aeffe1cd"
+checksum = "0ca2a8cb5805ce9e3b95435e3765b7b553cecc762d938d409434338386cb5775"
 dependencies = [
 "proc-macro2",
 "quote",
@@ -1639,12 +1655,6 @@ dependencies = [
 ]
 [[package]]
-name = "stable_deref_trait"
-version = "1.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a8f112729512f8e442d81f95a8a7ddf2b7c6b8a1a6f509a95864142b30cab2d3"
-[[package]]
 name = "stdx"
 version = "0.0.0"
 dependencies = [
@@ -1872,17 +1882,6 @@ dependencies = [
 ]
 [[package]]
-name = "triomphe"
-version = "0.1.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6e9d872053cf9e5a833d8c1dd772cdc38ab66a908129d6f73c049c986161d07c"
-dependencies = [
- "memoffset 0.5.6",
- "serde",
- "stable_deref_trait",
-]
-[[package]]
 name = "tt"
 version = "0.0.0"
 dependencies = [
diff --git a/crates/assists/src/handlers/generate_function.rs b/crates/assists/src/handlers/generate_function.rs
index 06ac85f67..1805c1dfd 100644
--- a/crates/assists/src/handlers/generate_function.rs
+++ b/crates/assists/src/handlers/generate_function.rs
@@ -158,11 +158,11 @@ impl FunctionBuilder {
                it.text_range().end()
            }
            GeneratedFunctionTarget::InEmptyItemList(it) => {
-                let indent = IndentLevel::from_node(it.syntax());
+                let indent = IndentLevel::from_node(&it);
                leading_ws = format!("\n{}", indent + 1);
                fn_def = fn_def.indent(indent + 1);
                trailing_ws = format!("\n{}", indent);
-                it.syntax().text_range().start() + TextSize::of('{')
+                it.text_range().start() + TextSize::of('{')
            }
        };
@@ -179,14 +179,14 @@ impl FunctionBuilder {
 enum GeneratedFunctionTarget {
    BehindItem(SyntaxNode),
-    InEmptyItemList(ast::ItemList),
+    InEmptyItemList(SyntaxNode),
 }
 impl GeneratedFunctionTarget {
    fn syntax(&self) -> &SyntaxNode {
        match self {
            GeneratedFunctionTarget::BehindItem(it) => it,
-            GeneratedFunctionTarget::InEmptyItemList(it) => it.syntax(),
+            GeneratedFunctionTarget::InEmptyItemList(it) => it,
        }
    }
 }
@@ -323,7 +323,16 @@ fn next_space_for_fn_in_module(
            if let Some(last_item) = it.item_list().and_then(|it| it.items().last()) {
                GeneratedFunctionTarget::BehindItem(last_item.syntax().clone())
            } else {
-                GeneratedFunctionTarget::InEmptyItemList(it.item_list()?)
+                GeneratedFunctionTarget::InEmptyItemList(it.item_list()?.syntax().clone())
+            }
+        }
+        hir::ModuleSource::BlockExpr(it) => {
+            if let Some(last_item) =
+                it.statements().take_while(|stmt| matches!(stmt, ast::Stmt::Item(_))).last()
+            {
+                GeneratedFunctionTarget::BehindItem(last_item.syntax().clone())
+            } else {
+                GeneratedFunctionTarget::InEmptyItemList(it.syntax().clone())
            }
        }
    };
diff --git a/crates/assists/src/handlers/generate_impl.rs b/crates/assists/src/handlers/generate_impl.rs
index 9af45192b..827477272 100644
--- a/crates/assists/src/handlers/generate_impl.rs
+++ b/crates/assists/src/handlers/generate_impl.rs
@@ -1,6 +1,9 @@
 use itertools::Itertools;
 use stdx::format_to;
-use syntax::ast::{self, AstNode, AttrsOwner, GenericParamsOwner, NameOwner};
+use syntax::{
+    ast::{self, AstNode, AttrsOwner, GenericParamsOwner, NameOwner},
+    SmolStr,
+};
 use crate::{AssistContext, AssistId, AssistKind, Assists};
@@ -49,16 +52,16 @@ pub(crate) fn generate_impl(acc: &mut Assists, ctx: &AssistContext) -> Option<()
                format_to!(buf, "{}", type_params.syntax());
            }
            buf.push_str(" ");
-            buf.push_str(name.text().as_str());
+            buf.push_str(name.text());
            if let Some(type_params) = type_params {
                let lifetime_params = type_params
                    .lifetime_params()
                    .filter_map(|it| it.lifetime())
-                    .map(|it| it.text().clone());
+                    .map(|it| SmolStr::from(it.text()));
                let type_params = type_params
                    .type_params()
                    .filter_map(|it| it.name())
-                    .map(|it| it.text().clone());
+                    .map(|it| SmolStr::from(it.text()));
                let generic_params = lifetime_params.chain(type_params).format(", ");
                format_to!(buf, "<{}>", generic_params)
diff --git a/crates/assists/src/handlers/generate_new.rs b/crates/assists/src/handlers/generate_new.rs
index 5c52b2bc8..b7390855a 100644
--- a/crates/assists/src/handlers/generate_new.rs
+++ b/crates/assists/src/handlers/generate_new.rs
@@ -3,7 +3,7 @@ use itertools::Itertools;
 use stdx::format_to;
 use syntax::{
    ast::{self, AstNode, GenericParamsOwner, NameOwner, StructKind, VisibilityOwner},
-    T,
+    SmolStr, T,
 };
 use crate::{AssistContext, AssistId, AssistKind, Assists};
@@ -95,14 +95,14 @@ fn generate_impl_text(strukt: &ast::Struct, code: &str) -> String {
        format_to!(buf, "{}", type_params.syntax());
    }
    buf.push_str(" ");
-    buf.push_str(strukt.name().unwrap().text().as_str());
+    buf.push_str(strukt.name().unwrap().text());
    if let Some(type_params) = type_params {
        let lifetime_params = type_params
            .lifetime_params()
            .filter_map(|it| it.lifetime())
-            .map(|it| it.text().clone());
+            .map(|it| SmolStr::from(it.text()));
        let type_params =
-            type_params.type_params().filter_map(|it| it.name()).map(|it| it.text().clone());
+            type_params.type_params().filter_map(|it| it.name()).map(|it| SmolStr::from(it.text()));
        format_to!(buf, "<{}>", lifetime_params.chain(type_params).format(", "))
    }
diff --git a/crates/assists/src/handlers/raw_string.rs b/crates/assists/src/handlers/raw_string.rs
index be963f162..d95267607 100644
--- a/crates/assists/src/handlers/raw_string.rs
+++ b/crates/assists/src/handlers/raw_string.rs
@@ -138,7 +138,7 @@ pub(crate) fn remove_hash(acc: &mut Assists, ctx: &AssistContext) -> Option<()>
        return None;
    }
-    let text = token.text().as_str();
+    let text = token.text();
    if !text.starts_with("r#") && text.ends_with('#') {
        return None;
    }
diff --git a/crates/assists/src/handlers/replace_derive_with_manual_impl.rs b/crates/assists/src/handlers/replace_derive_with_manual_impl.rs
index bd4c1c806..6aa9d2f2c 100644
--- a/crates/assists/src/handlers/replace_derive_with_manual_impl.rs
+++ b/crates/assists/src/handlers/replace_derive_with_manual_impl.rs
@@ -3,7 +3,7 @@ use ide_db::imports_locator;
 use itertools::Itertools;
 use syntax::{
    ast::{self, make, AstNode},
-    Direction, SmolStr,
+    Direction,
    SyntaxKind::{IDENT, WHITESPACE},
    TextSize,
 };
@@ -43,17 +43,18 @@ pub(crate) fn replace_derive_with_manual_impl(
 ) -> Option<()> {
    let attr = ctx.find_node_at_offset::<ast::Attr>()?;
-    let attr_name = attr
+    let has_derive = attr
        .syntax()
        .descendants_with_tokens()
        .filter(|t| t.kind() == IDENT)
        .find_map(syntax::NodeOrToken::into_token)
-        .filter(|t| t.text() == "derive")?
+        .filter(|t| t.text() == "derive")
-        .text()
+        .is_some();
-        .clone();
+    if !has_derive {
+        return None;
+    }
-    let trait_token =
+    let trait_token = ctx.token_at_offset().find(|t| t.kind() == IDENT && t.text() != "derive")?;
-        ctx.token_at_offset().find(|t| t.kind() == IDENT && *t.text() != attr_name)?;
    let trait_path = make::path_unqualified(make::path_segment(make::name_ref(trait_token.text())));
    let annotated_name = attr.syntax().siblings(Direction::Next).find_map(ast::Name::cast)?;
@@ -176,9 +177,9 @@ fn update_attribute(
        .syntax()
        .descendants_with_tokens()
        .filter(|t| t.kind() == IDENT)
-        .filter_map(|t| t.into_token().map(|t| t.text().clone()))
+        .filter_map(|t| t.into_token().map(|t| t.text().to_string()))
        .filter(|t| t != trait_name.text())
-        .collect::<Vec<SmolStr>>();
+        .collect::<Vec<_>>();
    let has_more_derives = !new_attr_input.is_empty();
    if has_more_derives {
diff --git a/crates/assists/src/utils.rs b/crates/assists/src/utils.rs
index fc9f83bab..44c35bafa 100644
--- a/crates/assists/src/utils.rs
+++ b/crates/assists/src/utils.rs
@@ -223,7 +223,7 @@ fn invert_special_case(expr: &ast::Expr) -> Option<ast::Expr> {
            let method = mce.name_ref()?;
            let arg_list = mce.arg_list()?;
-            let method = match method.text().as_str() {
+            let method = match method.text() {
                "is_some" => "is_none",
                "is_none" => "is_some",
                "is_ok" => "is_err",
diff --git a/crates/hir/src/attrs.rs b/crates/hir/src/attrs.rs
index 99fb65bac..9e6a3e155 100644
--- a/crates/hir/src/attrs.rs
+++ b/crates/hir/src/attrs.rs
@@ -2,6 +2,7 @@
 use hir_def::{
    attr::{Attrs, Documentation},
    path::ModPath,
+    per_ns::PerNs,
    resolver::HasResolver,
    AttrDefId, GenericParamId, ModuleDefId,
 };
@@ -112,6 +113,11 @@ fn resolve_doc_path(
    let path = ast::Path::parse(link).ok()?;
    let modpath = ModPath::from_src(path, &Hygiene::new_unhygienic()).unwrap();
    let resolved = resolver.resolve_module_path_in_items(db.upcast(), &modpath);
+    if resolved == PerNs::none() {
+        if let Some(trait_id) = resolver.resolve_module_path_in_trait_items(db.upcast(), &modpath) {
+            return Some(ModuleDefId::TraitId(trait_id));
+        };
+    }
    let def = match ns {
        Some(Namespace::Types) => resolved.take_types()?,
        Some(Namespace::Values) => resolved.take_values()?,
diff --git a/crates/hir/src/code_model.rs b/crates/hir/src/code_model.rs
index a4141e111..aaa7013b6 100644
--- a/crates/hir/src/code_model.rs
+++ b/crates/hir/src/code_model.rs
@@ -90,7 +90,7 @@ impl Crate {
    }
    pub fn root_module(self, db: &dyn HirDatabase) -> Module {
-        let module_id = db.crate_def_map(self.id).root;
+        let module_id = db.crate_def_map(self.id).root();
        Module::new(self, module_id)
    }
@@ -302,7 +302,7 @@ impl Module {
    /// in the module tree of any target in `Cargo.toml`.
    pub fn crate_root(self, db: &dyn HirDatabase) -> Module {
        let def_map = db.crate_def_map(self.id.krate);
-        self.with_module_id(def_map.root)
+        self.with_module_id(def_map.root())
    }
    /// Iterates over all child modules.
@@ -1000,7 +1000,7 @@ impl MacroDef {
    /// early, in `hir_expand`, where modules simply do not exist yet.
    pub fn module(self, db: &dyn HirDatabase) -> Option<Module> {
        let krate = self.id.krate;
-        let module_id = db.crate_def_map(krate).root;
+        let module_id = db.crate_def_map(krate).root();
        Some(Module::new(Crate { id: krate }, module_id))
    }
diff --git a/crates/hir/src/db.rs b/crates/hir/src/db.rs
index d5d4cf5b6..d444f4bbb 100644
--- a/crates/hir/src/db.rs
+++ b/crates/hir/src/db.rs
@@ -1,13 +1,13 @@
 //! FIXME: write short doc here
 pub use hir_def::db::{
-    AttrsQuery, BodyQuery, BodyWithSourceMapQuery, ConstDataQuery, CrateDefMapQueryQuery,
+    AttrsQuery, BlockDefMapQuery, BodyQuery, BodyWithSourceMapQuery, ConstDataQuery,
-    CrateLangItemsQuery, DefDatabase, DefDatabaseStorage, EnumDataQuery, ExprScopesQuery,
+    CrateDefMapQueryQuery, CrateLangItemsQuery, DefDatabase, DefDatabaseStorage, EnumDataQuery,
-    FunctionDataQuery, GenericParamsQuery, ImplDataQuery, ImportMapQuery, InternConstQuery,
+    ExprScopesQuery, FunctionDataQuery, GenericParamsQuery, ImplDataQuery, ImportMapQuery,
-    InternDatabase, InternDatabaseStorage, InternEnumQuery, InternFunctionQuery, InternImplQuery,
+    InternConstQuery, InternDatabase, InternDatabaseStorage, InternEnumQuery, InternFunctionQuery,
-    InternStaticQuery, InternStructQuery, InternTraitQuery, InternTypeAliasQuery, InternUnionQuery,
+    InternImplQuery, InternStaticQuery, InternStructQuery, InternTraitQuery, InternTypeAliasQuery,
-    ItemTreeQuery, LangItemQuery, StaticDataQuery, StructDataQuery, TraitDataQuery,
+    InternUnionQuery, ItemTreeQuery, LangItemQuery, StaticDataQuery, StructDataQuery,
-    TypeAliasDataQuery, UnionDataQuery,
+    TraitDataQuery, TypeAliasDataQuery, UnionDataQuery,
 };
 pub use hir_expand::db::{
    AstDatabase, AstDatabaseStorage, AstIdMapQuery, HygieneFrameQuery, InternEagerExpansionQuery,
diff --git a/crates/hir_def/src/attr.rs b/crates/hir_def/src/attr.rs
index 1b09ff816..c72649c41 100644
--- a/crates/hir_def/src/attr.rs
+++ b/crates/hir_def/src/attr.rs
@@ -207,6 +207,7 @@ impl Attrs {
                        mod_data.definition_source(db).as_ref().map(|src| match src {
                            ModuleSource::SourceFile(file) => file as &dyn AttrsOwner,
                            ModuleSource::Module(module) => module as &dyn AttrsOwner,
+                            ModuleSource::BlockExpr(block) => block as &dyn AttrsOwner,
                        }),
                    ),
                }
diff --git a/crates/hir_def/src/body.rs b/crates/hir_def/src/body.rs
index 3b2dd0f6e..2c2c999dd 100644
--- a/crates/hir_def/src/body.rs
+++ b/crates/hir_def/src/body.rs
@@ -122,7 +122,7 @@ impl Expander {
        let mut err = None;
        let call_id =
-            macro_call.as_call_id_with_errors(db, self.crate_def_map.krate, resolver, &mut |e| {
+            macro_call.as_call_id_with_errors(db, self.crate_def_map.krate(), resolver, &mut |e| {
                err.get_or_insert(e);
            });
        let call_id = match call_id {
diff --git a/crates/hir_def/src/body/tests.rs b/crates/hir_def/src/body/tests.rs
index de77d5fc9..2e5d0a01e 100644
--- a/crates/hir_def/src/body/tests.rs
+++ b/crates/hir_def/src/body/tests.rs
@@ -6,18 +6,24 @@ use crate::{test_db::TestDB, ModuleDefId};
 use super::*;
 fn lower(ra_fixture: &str) -> Arc<Body> {
-    let (db, file_id) = crate::test_db::TestDB::with_single_file(ra_fixture);
+    let db = crate::test_db::TestDB::with_files(ra_fixture);
    let krate = db.crate_graph().iter().next().unwrap();
    let def_map = db.crate_def_map(krate);
-    let module = def_map.modules_for_file(file_id).next().unwrap();
+    let mut fn_def = None;
-    let module = &def_map[module];
+    'outer: for (_, module) in def_map.modules() {
-    let fn_def = match module.scope.declarations().next().unwrap() {
+        for decl in module.scope.declarations() {
-        ModuleDefId::FunctionId(it) => it,
+            match decl {
-        _ => panic!(),
+                ModuleDefId::FunctionId(it) => {
-    };
+                    fn_def = Some(it);
+                    break 'outer;
+                }
+                _ => {}
+            }
+        }
+    }
-    db.body(fn_def.into())
+    db.body(fn_def.unwrap().into())
 }
 fn check_diagnostics(ra_fixture: &str) {
@@ -42,6 +48,25 @@ fn main() { n_nuple!(1,2,3); }
 }
 #[test]
+fn macro_resolve() {
+    // Regression test for a path resolution bug introduced with inner item handling.
+    lower(
+        r"
+macro_rules! vec {
+    () => { () };
+    ($elem:expr; $n:expr) => { () };
+    ($($x:expr),+ $(,)?) => { () };
+}
+mod m {
+    fn outer() {
+        let _ = vec![FileSet::default(); self.len()];
+    }
+}
+      ",
+    );
+}
+#[test]
 fn cfg_diagnostics() {
    check_diagnostics(
        r"
diff --git a/crates/hir_def/src/db.rs b/crates/hir_def/src/db.rs
index 91c8d45cd..a87c80b8a 100644
--- a/crates/hir_def/src/db.rs
+++ b/crates/hir_def/src/db.rs
@@ -2,9 +2,9 @@
 use std::sync::Arc;
 use base_db::{salsa, CrateId, SourceDatabase, Upcast};
-use hir_expand::{db::AstDatabase, HirFileId};
+use hir_expand::{db::AstDatabase, AstId, HirFileId};
 use la_arena::ArenaMap;
-use syntax::SmolStr;
+use syntax::{ast, SmolStr};
 use crate::{
    adt::{EnumData, StructData},
@@ -55,6 +55,9 @@ pub trait DefDatabase: InternDatabase + AstDatabase + Upcast<dyn AstDatabase> {
    #[salsa::invoke(DefMap::crate_def_map_query)]
    fn crate_def_map_query(&self, krate: CrateId) -> Arc<DefMap>;
+    #[salsa::invoke(DefMap::block_def_map_query)]
+    fn block_def_map(&self, krate: CrateId, block: AstId<ast::BlockExpr>) -> Arc<DefMap>;
    #[salsa::invoke(StructData::struct_data_query)]
    fn struct_data(&self, id: StructId) -> Arc<StructData>;
    #[salsa::invoke(StructData::union_data_query)]
diff --git a/crates/hir_def/src/find_path.rs b/crates/hir_def/src/find_path.rs
index 422a6eeb4..db2d125ae 100644
--- a/crates/hir_def/src/find_path.rs
+++ b/crates/hir_def/src/find_path.rs
@@ -51,7 +51,7 @@ fn check_self_super(def_map: &DefMap, item: ItemInNs, from: ModuleId) -> Option<
    if item == ItemInNs::Types(from.into()) {
        // - if the item is the module we're in, use `self`
        Some(ModPath::from_segments(PathKind::Super(0), Vec::new()))
-    } else if let Some(parent_id) = def_map.modules[from.local_id].parent {
+    } else if let Some(parent_id) = def_map[from.local_id].parent {
        // - if the item is the parent module, use `super` (this is not used recursively, since `super::super` is ugly)
        if item
            == ItemInNs::Types(ModuleDefId::ModuleId(ModuleId {
@@ -111,7 +111,7 @@ fn find_path_inner(
    // - if the item is already in scope, return the name under which it is
    let def_map = db.crate_def_map(from.krate);
-    let from_scope: &crate::item_scope::ItemScope = &def_map.modules[from.local_id].scope;
+    let from_scope: &crate::item_scope::ItemScope = &def_map[from.local_id].scope;
    let scope_name =
        if let Some((name, _)) = from_scope.name_of(item) { Some(name.clone()) } else { None };
    if prefixed.is_none() && scope_name.is_some() {
@@ -123,7 +123,7 @@ fn find_path_inner(
    if item
        == ItemInNs::Types(ModuleDefId::ModuleId(ModuleId {
            krate: from.krate,
-            local_id: def_map.root,
+            local_id: def_map.root(),
        }))
    {
        return Some(ModPath::from_segments(PathKind::Crate, Vec::new()));
@@ -136,7 +136,7 @@ fn find_path_inner(
    }
    // - if the item is the crate root of a dependency crate, return the name from the extern prelude
-    for (name, def_id) in &def_map.extern_prelude {
+    for (name, def_id) in def_map.extern_prelude() {
        if item == ItemInNs::Types(*def_id) {
            let name = scope_name.unwrap_or_else(|| name.clone());
            return Some(ModPath::from_segments(PathKind::Plain, vec![name]));
@@ -144,10 +144,10 @@ fn find_path_inner(
    }
    // - if the item is in the prelude, return the name from there
-    if let Some(prelude_module) = def_map.prelude {
+    if let Some(prelude_module) = def_map.prelude() {
        let prelude_def_map = db.crate_def_map(prelude_module.krate);
        let prelude_scope: &crate::item_scope::ItemScope =
-            &prelude_def_map.modules[prelude_module.local_id].scope;
+            &prelude_def_map[prelude_module.local_id].scope;
        if let Some((name, vis)) = prelude_scope.name_of(item) {
            if vis.is_visible_from(db, from) {
                return Some(ModPath::from_segments(PathKind::Plain, vec![name.clone()]));
@@ -175,7 +175,7 @@ fn find_path_inner(
    // - otherwise, look for modules containing (reexporting) it and import it from one of those
-    let crate_root = ModuleId { local_id: def_map.root, krate: from.krate };
+    let crate_root = ModuleId { local_id: def_map.root(), krate: from.krate };
    let crate_attrs = db.attrs(crate_root.into());
    let prefer_no_std = crate_attrs.by_key("no_std").exists();
    let mut best_path = None;
@@ -287,7 +287,7 @@ fn find_local_import_locations(
    // Compute the initial worklist. We start with all direct child modules of `from` as well as all
    // of its (recursive) parent modules.
-    let data = &def_map.modules[from.local_id];
+    let data = &def_map[from.local_id];
    let mut worklist = data
        .children
        .values()
@@ -296,7 +296,7 @@ fn find_local_import_locations(
    let mut parent = data.parent;
    while let Some(p) = parent {
        worklist.push(ModuleId { krate: from.krate, local_id: p });
-        parent = def_map.modules[p].parent;
+        parent = def_map[p].parent;
    }
    let mut seen: FxHashSet<_> = FxHashSet::default();
diff --git a/crates/hir_def/src/import_map.rs b/crates/hir_def/src/import_map.rs
index fac0de90c..0251d016b 100644
--- a/crates/hir_def/src/import_map.rs
+++ b/crates/hir_def/src/import_map.rs
@@ -75,7 +75,7 @@ impl ImportMap {
        // We look only into modules that are public(ly reexported), starting with the crate root.
        let empty = ImportPath { segments: vec![] };
-        let root = ModuleId { krate, local_id: def_map.root };
+        let root = ModuleId { krate, local_id: def_map.root() };
        let mut worklist = vec![(root, empty)];
        while let Some((module, mod_path)) = worklist.pop() {
            let ext_def_map;
diff --git a/crates/hir_def/src/item_tree.rs b/crates/hir_def/src/item_tree.rs
index ff62928df..b8d7608e7 100644
--- a/crates/hir_def/src/item_tree.rs
+++ b/crates/hir_def/src/item_tree.rs
@@ -21,6 +21,7 @@ use hir_expand::{
    HirFileId, InFile,
 };
 use la_arena::{Arena, Idx, RawIdx};
+use profile::Count;
 use rustc_hash::FxHashMap;
 use smallvec::SmallVec;
 use syntax::{ast, match_ast};
@@ -67,15 +68,16 @@ impl GenericParamsId {
 /// The item tree of a source file.
 #[derive(Debug, Eq, PartialEq)]
 pub struct ItemTree {
+    _c: Count<Self>,
    top_level: SmallVec<[ModItem; 1]>,
    attrs: FxHashMap<AttrOwner, RawAttrs>,
-    inner_items: FxHashMap<FileAstId<ast::Item>, SmallVec<[ModItem; 1]>>,
    data: Option<Box<ItemTreeData>>,
 }
 impl ItemTree {
-    pub fn item_tree_query(db: &dyn DefDatabase, file_id: HirFileId) -> Arc<ItemTree> {
+    pub(crate) fn item_tree_query(db: &dyn DefDatabase, file_id: HirFileId) -> Arc<ItemTree> {
        let _p = profile::span("item_tree_query").detail(|| format!("{:?}", file_id));
        let syntax = if let Some(node) = db.parse_or_expand(file_id) {
            node
@@ -118,9 +120,9 @@ impl ItemTree {
    fn empty() -> Self {
        Self {
+            _c: Count::new(),
            top_level: Default::default(),
            attrs: Default::default(),
-            inner_items: Default::default(),
            data: Default::default(),
        }
    }
@@ -147,6 +149,7 @@ impl ItemTree {
                macro_defs,
                vis,
                generics,
+                inner_items,
            } = &mut **data;
            imports.shrink_to_fit();
@@ -169,6 +172,8 @@ impl ItemTree {
            vis.arena.shrink_to_fit();
            generics.arena.shrink_to_fit();
+            inner_items.shrink_to_fit();
        }
    }
@@ -191,16 +196,18 @@ impl ItemTree {
        self.raw_attrs(of).clone().filter(db, krate)
    }
-    /// Returns the lowered inner items that `ast` corresponds to.
+    pub fn all_inner_items(&self) -> impl Iterator<Item = ModItem> + '_ {
-    ///
+        match &self.data {
-    /// Most AST items are lowered to a single `ModItem`, but some (eg. `use` items) may be lowered
+            Some(data) => Some(data.inner_items.values().flatten().copied()).into_iter().flatten(),
-    /// to multiple items in the `ItemTree`.
+            None => None.into_iter().flatten(),
-    pub fn inner_items(&self, ast: FileAstId<ast::Item>) -> &[ModItem] {
+        }
-        &self.inner_items[&ast]
    }
-    pub fn all_inner_items(&self) -> impl Iterator<Item = ModItem> + '_ {
+    pub fn inner_items_of_block(&self, block: FileAstId<ast::BlockExpr>) -> &[ModItem] {
-        self.inner_items.values().flatten().copied()
+        match &self.data {
+            Some(data) => data.inner_items.get(&block).map(|it| &**it).unwrap_or(&[]),
+            None => &[],
+        }
    }
    pub fn source<S: ItemTreeNode>(&self, db: &dyn DefDatabase, of: ItemTreeId<S>) -> S::Source {
@@ -297,6 +304,8 @@ struct ItemTreeData {
    vis: ItemVisibilities,
    generics: GenericParamsStorage,
+    inner_items: FxHashMap<FileAstId<ast::BlockExpr>, SmallVec<[ModItem; 1]>>,
 }
 #[derive(Debug, Eq, PartialEq, Hash)]
diff --git a/crates/hir_def/src/item_tree/lower.rs b/crates/hir_def/src/item_tree/lower.rs
index 5e71ca42c..ce470fc3b 100644
--- a/crates/hir_def/src/item_tree/lower.rs
+++ b/crates/hir_def/src/item_tree/lower.rs
@@ -6,7 +6,7 @@ use hir_expand::{ast_id_map::AstIdMap, hygiene::Hygiene, name::known, HirFileId}
 use smallvec::SmallVec;
 use syntax::{
    ast::{self, ModuleItemOwner},
-    SyntaxNode,
+    SyntaxNode, WalkEvent,
 };
 use crate::{
@@ -37,7 +37,6 @@ pub(super) struct Ctx {
    file: HirFileId,
    source_ast_id_map: Arc<AstIdMap>,
    body_ctx: crate::body::LowerCtx,
-    inner_items: Vec<ModItem>,
    forced_visibility: Option<RawVisibilityId>,
 }
@@ -49,7 +48,6 @@ impl Ctx {
            file,
            source_ast_id_map: db.ast_id_map(file),
            body_ctx: crate::body::LowerCtx::new(db, file),
-            inner_items: Vec::new(),
            forced_visibility: None,
        }
    }
@@ -73,8 +71,6 @@ impl Ctx {
    }
    fn lower_mod_item(&mut self, item: &ast::Item, inner: bool) -> Option<ModItems> {
-        assert!(inner || self.inner_items.is_empty());
        // Collect inner items for 1-to-1-lowered items.
        match item {
            ast::Item::Struct(_)
@@ -150,14 +146,37 @@ impl Ctx {
    fn collect_inner_items(&mut self, container: &SyntaxNode) {
        let forced_vis = self.forced_visibility.take();
-        let mut inner_items = mem::take(&mut self.tree.inner_items);
-        inner_items.extend(container.descendants().skip(1).filter_map(ast::Item::cast).filter_map(
+        let mut block_stack = Vec::new();
-            |item| {
+        for event in container.preorder().skip(1) {
-                let ast_id = self.source_ast_id_map.ast_id(&item);
+            match event {
-                Some((ast_id, self.lower_mod_item(&item, true)?.0))
+                WalkEvent::Enter(node) => {
-            },
+                    match_ast! {
-        ));
+                        match node {
-        self.tree.inner_items = inner_items;
+                            ast::BlockExpr(block) => {
+                                block_stack.push(self.source_ast_id_map.ast_id(&block));
+                            },
+                            ast::Item(item) => {
+                                let mod_items = self.lower_mod_item(&item, true);
+                                let current_block = block_stack.last();
+                                if let (Some(mod_items), Some(block)) = (mod_items, current_block) {
+                                    if !mod_items.0.is_empty() {
+                                        self.data().inner_items.entry(*block).or_default().extend(mod_items.0.iter().copied());
+                                    }
+                                }
+                            },
+                            _ => {}
+                        }
+                    }
+                }
+                WalkEvent::Leave(node) => {
+                    if ast::BlockExpr::cast(node).is_some() {
+                        block_stack.pop();
+                    }
+                }
+            }
+        }
        self.forced_visibility = forced_vis;
    }
diff --git a/crates/hir_def/src/lang_item.rs b/crates/hir_def/src/lang_item.rs
index 30188b740..9e90f745c 100644
--- a/crates/hir_def/src/lang_item.rs
+++ b/crates/hir_def/src/lang_item.rs
@@ -84,7 +84,7 @@ impl LangItems {
        let crate_def_map = db.crate_def_map(krate);
-        for (_, module_data) in crate_def_map.modules.iter() {
+        for (_, module_data) in crate_def_map.modules() {
            for impl_def in module_data.scope.impls() {
                lang_items.collect_lang_item(db, impl_def, LangItemTarget::ImplDefId)
            }
diff --git a/crates/hir_def/src/nameres.rs b/crates/hir_def/src/nameres.rs
index 769a557ad..bd3ea9b8b 100644
--- a/crates/hir_def/src/nameres.rs
+++ b/crates/hir_def/src/nameres.rs
@@ -59,9 +59,10 @@ use std::sync::Arc;
 use base_db::{CrateId, Edition, FileId};
 use hir_expand::{diagnostics::DiagnosticSink, name::Name, InFile};
 use la_arena::Arena;
+use profile::Count;
 use rustc_hash::FxHashMap;
 use stdx::format_to;
-use syntax::ast;
+use syntax::{ast, AstNode};
 use crate::{
    db::DefDatabase,
@@ -75,14 +76,16 @@ use crate::{
 /// Contains all top-level defs from a macro-expanded crate
 #[derive(Debug, PartialEq, Eq)]
 pub struct DefMap {
-    pub root: LocalModuleId,
+    _c: Count<Self>,
-    pub modules: Arena<ModuleData>,
+    parent: Option<Arc<DefMap>>,
-    pub(crate) krate: CrateId,
+    root: LocalModuleId,
+    modules: Arena<ModuleData>,
+    krate: CrateId,
    /// The prelude module for this crate. This either comes from an import
    /// marked with the `prelude_import` attribute, or (in the normal case) from
    /// a dependency (`std` or `core`).
-    pub(crate) prelude: Option<ModuleId>,
+    prelude: Option<ModuleId>,
-    pub(crate) extern_prelude: FxHashMap<Name, ModuleDefId>,
+    extern_prelude: FxHashMap<Name, ModuleDefId>,
    edition: Edition,
    diagnostics: Vec<DefDiagnostic>,
@@ -109,6 +112,10 @@ pub enum ModuleOrigin {
    Inline {
        definition: AstId<ast::Module>,
    },
+    /// Pseudo-module introduced by a block scope (contains only inner items).
+    BlockExpr {
+        block: AstId<ast::BlockExpr>,
+    },
 }
 impl Default for ModuleOrigin {
@@ -122,7 +129,7 @@ impl ModuleOrigin {
        match self {
            ModuleOrigin::File { declaration: module, .. }
            | ModuleOrigin::Inline { definition: module, .. } => Some(*module),
-            ModuleOrigin::CrateRoot { .. } => None,
+            ModuleOrigin::CrateRoot { .. } | ModuleOrigin::BlockExpr { .. } => None,
        }
    }
@@ -137,7 +144,7 @@ impl ModuleOrigin {
    pub fn is_inline(&self) -> bool {
        match self {
-            ModuleOrigin::Inline { .. } => true,
+            ModuleOrigin::Inline { .. } | ModuleOrigin::BlockExpr { .. } => true,
            ModuleOrigin::CrateRoot { .. } | ModuleOrigin::File { .. } => false,
        }
    }
@@ -155,6 +162,9 @@ impl ModuleOrigin {
                definition.file_id,
                ModuleSource::Module(definition.to_node(db.upcast())),
            ),
+            ModuleOrigin::BlockExpr { block } => {
+                InFile::new(block.file_id, ModuleSource::BlockExpr(block.to_node(db.upcast())))
+            }
        }
    }
 }
@@ -174,24 +184,51 @@ impl DefMap {
        let _p = profile::span("crate_def_map_query").detail(|| {
            db.crate_graph()[krate].display_name.as_deref().unwrap_or_default().to_string()
        });
-        let def_map = {
+        let edition = db.crate_graph()[krate].edition;
-            let edition = db.crate_graph()[krate].edition;
+        let def_map = DefMap::empty(krate, edition);
-            let mut modules: Arena<ModuleData> = Arena::default();
+        let def_map = collector::collect_defs(db, def_map, None);
-            let root = modules.alloc(ModuleData::default());
-            DefMap {
-                krate,
-                edition,
-                extern_prelude: FxHashMap::default(),
-                prelude: None,
-                root,
-                modules,
-                diagnostics: Vec::new(),
-            }
-        };
-        let def_map = collector::collect_defs(db, def_map);
        Arc::new(def_map)
    }
+    pub(crate) fn block_def_map_query(
+        db: &dyn DefDatabase,
+        krate: CrateId,
+        block: AstId<ast::BlockExpr>,
+    ) -> Arc<DefMap> {
+        let item_tree = db.item_tree(block.file_id);
+        let block_items = item_tree.inner_items_of_block(block.value);
+        let parent = parent_def_map(db, krate, block);
+        if block_items.is_empty() {
+            // If there are no inner items, nothing new is brought into scope, so we can just return
+            // the parent DefMap. This keeps DefMap parent chains short.
+            return parent;
+        }
+        let mut def_map = DefMap::empty(krate, parent.edition);
+        def_map.parent = Some(parent);
+        let def_map = collector::collect_defs(db, def_map, Some(block.value));
+        Arc::new(def_map)
+    }
+    fn empty(krate: CrateId, edition: Edition) -> DefMap {
+        let mut modules: Arena<ModuleData> = Arena::default();
+        let root = modules.alloc(ModuleData::default());
+        DefMap {
+            _c: Count::new(),
+            parent: None,
+            krate,
+            edition,
+            extern_prelude: FxHashMap::default(),
+            prelude: None,
+            root,
+            modules,
+            diagnostics: Vec::new(),
+        }
+    }
    pub fn add_diagnostics(
        &self,
        db: &dyn DefDatabase,
@@ -208,6 +245,26 @@ impl DefMap {
            .map(|(id, _data)| id)
    }
+    pub fn modules(&self) -> impl Iterator<Item = (LocalModuleId, &ModuleData)> + '_ {
+        self.modules.iter()
+    }
+    pub fn root(&self) -> LocalModuleId {
+        self.root
+    }
+    pub(crate) fn krate(&self) -> CrateId {
+        self.krate
+    }
+    pub(crate) fn prelude(&self) -> Option<ModuleId> {
+        self.prelude
+    }
+    pub(crate) fn extern_prelude(&self) -> impl Iterator<Item = (&Name, &ModuleDefId)> + '_ {
+        self.extern_prelude.iter()
+    }
    pub(crate) fn resolve_path(
        &self,
        db: &dyn DefDatabase,
@@ -224,7 +281,12 @@ impl DefMap {
    // even), as this should be a great debugging aid.
    pub fn dump(&self) -> String {
        let mut buf = String::new();
-        go(&mut buf, self, "crate", self.root);
+        let mut current_map = self;
+        while let Some(parent) = &current_map.parent {
+            go(&mut buf, current_map, "block scope", current_map.root);
+            current_map = &**parent;
+        }
+        go(&mut buf, current_map, "crate", current_map.root);
        return buf;
        fn go(buf: &mut String, map: &DefMap, path: &str, module: LocalModuleId) {
@@ -276,10 +338,40 @@ impl ModuleData {
    }
 }
+fn parent_def_map(
+    db: &dyn DefDatabase,
+    krate: CrateId,
+    block: AstId<ast::BlockExpr>,
+) -> Arc<DefMap> {
+    // FIXME: store this info in the item tree instead of reparsing here
+    let ast_id_map = db.ast_id_map(block.file_id);
+    let block_ptr = ast_id_map.get(block.value);
+    let root = match db.parse_or_expand(block.file_id) {
+        Some(it) => it,
+        None => {
+            return Arc::new(DefMap::empty(krate, Edition::Edition2018));
+        }
+    };
+    let ast = block_ptr.to_node(&root);
+    for ancestor in ast.syntax().ancestors().skip(1) {
+        if let Some(block_expr) = ast::BlockExpr::cast(ancestor) {
+            let ancestor_id = ast_id_map.ast_id(&block_expr);
+            let ast_id = InFile::new(block.file_id, ancestor_id);
+            let parent_map = db.block_def_map(krate, ast_id);
+            return parent_map;
+        }
+    }
+    // No enclosing block scope, so the parent is the crate-level DefMap.
+    db.crate_def_map(krate)
+}
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum ModuleSource {
    SourceFile(ast::SourceFile),
    Module(ast::Module),
+    BlockExpr(ast::BlockExpr),
 }
 mod diagnostics {
diff --git a/crates/hir_def/src/nameres/collector.rs b/crates/hir_def/src/nameres/collector.rs
index 61da56340..cd68efbe6 100644
--- a/crates/hir_def/src/nameres/collector.rs
+++ b/crates/hir_def/src/nameres/collector.rs
@@ -45,7 +45,11 @@ const GLOB_RECURSION_LIMIT: usize = 100;
 const EXPANSION_DEPTH_LIMIT: usize = 128;
 const FIXED_POINT_LIMIT: usize = 8192;
-pub(super) fn collect_defs(db: &dyn DefDatabase, mut def_map: DefMap) -> DefMap {
+pub(super) fn collect_defs(
+    db: &dyn DefDatabase,
+    mut def_map: DefMap,
+    block: Option<FileAstId<ast::BlockExpr>>,
+) -> DefMap {
    let crate_graph = db.crate_graph();
    // populate external prelude
@@ -93,6 +97,14 @@ pub(super) fn collect_defs(db: &dyn DefDatabase, mut def_map: DefMap) -> DefMap
        exports_proc_macros: false,
        from_glob_import: Default::default(),
    };
+    match block {
+        Some(block) => {
+            collector.seed_with_inner(block);
+        }
+        None => {
+            collector.seed_with_top_level();
+        }
+    }
    collector.collect();
    collector.finish()
 }
@@ -228,7 +240,7 @@ struct DefCollector<'a> {
 }
 impl DefCollector<'_> {
-    fn collect(&mut self) {
+    fn seed_with_top_level(&mut self) {
        let file_id = self.db.crate_graph()[self.def_map.krate].root_file_id;
        let item_tree = self.db.item_tree(file_id.into());
        let module_id = self.def_map.root;
@@ -248,7 +260,31 @@ impl DefCollector<'_> {
            }
            .collect(item_tree.top_level_items());
        }
+    }
+    fn seed_with_inner(&mut self, block: FileAstId<ast::BlockExpr>) {
+        let file_id = self.db.crate_graph()[self.def_map.krate].root_file_id;
+        let item_tree = self.db.item_tree(file_id.into());
+        let module_id = self.def_map.root;
+        self.def_map.modules[module_id].origin = ModuleOrigin::CrateRoot { definition: file_id };
+        if item_tree
+            .top_level_attrs(self.db, self.def_map.krate)
+            .cfg()
+            .map_or(true, |cfg| self.cfg_options.check(&cfg) != Some(false))
+        {
+            ModCollector {
+                def_collector: &mut *self,
+                macro_depth: 0,
+                module_id,
+                file_id: file_id.into(),
+                item_tree: &item_tree,
+                mod_dir: ModDir::root(),
+            }
+            .collect(item_tree.inner_items_of_block(block));
+        }
+    }
+    fn collect(&mut self) {
        // main name resolution fixed-point loop.
        let mut i = 0;
        loop {
@@ -1470,7 +1506,6 @@ impl ModCollector<'_, '_> {
 mod tests {
    use crate::{db::DefDatabase, test_db::TestDB};
    use base_db::{fixture::WithFixture, SourceDatabase};
-    use la_arena::Arena;
    use super::*;
@@ -1489,6 +1524,7 @@ mod tests {
            exports_proc_macros: false,
            from_glob_import: Default::default(),
        };
+        collector.seed_with_top_level();
        collector.collect();
        collector.def_map
    }
@@ -1497,20 +1533,8 @@ mod tests {
        let (db, _file_id) = TestDB::with_single_file(&code);
        let krate = db.test_crate();
-        let def_map = {
+        let edition = db.crate_graph()[krate].edition;
-            let edition = db.crate_graph()[krate].edition;
+        let def_map = DefMap::empty(krate, edition);
-            let mut modules: Arena<ModuleData> = Arena::default();
-            let root = modules.alloc(ModuleData::default());
-            DefMap {
-                krate,
-                edition,
-                extern_prelude: FxHashMap::default(),
-                prelude: None,
-                root,
-                modules,
-                diagnostics: Vec::new(),
-            }
-        };
        do_collect_defs(&db, def_map)
    }
diff --git a/crates/hir_def/src/nameres/path_resolution.rs b/crates/hir_def/src/nameres/path_resolution.rs
index 096a7d0ac..ec90f4e65 100644
--- a/crates/hir_def/src/nameres/path_resolution.rs
+++ b/crates/hir_def/src/nameres/path_resolution.rs
@@ -104,6 +104,43 @@ impl DefMap {
        path: &ModPath,
        shadow: BuiltinShadowMode,
    ) -> ResolvePathResult {
+        let mut result = ResolvePathResult::empty(ReachedFixedPoint::No);
+        result.segment_index = Some(usize::max_value());
+        let mut current_map = self;
+        loop {
+            let new = current_map.resolve_path_fp_with_macro_single(
+                db,
+                mode,
+                original_module,
+                path,
+                shadow,
+            );
+            // Merge `new` into `result`.
+            result.resolved_def = result.resolved_def.or(new.resolved_def);
+            if result.reached_fixedpoint == ReachedFixedPoint::No {
+                result.reached_fixedpoint = new.reached_fixedpoint;
+            }
+            // FIXME: this doesn't seem right; what if the different namespace resolutions come from different crates?
+            result.krate = result.krate.or(new.krate);
+            result.segment_index = result.segment_index.min(new.segment_index);
+            match &current_map.parent {
+                Some(map) => current_map = map,
+                None => return result,
+            }
+        }
+    }
+    pub(super) fn resolve_path_fp_with_macro_single(
+        &self,
+        db: &dyn DefDatabase,
+        mode: ResolveMode,
+        original_module: LocalModuleId,
+        path: &ModPath,
+        shadow: BuiltinShadowMode,
+    ) -> ResolvePathResult {
        let mut segments = path.segments.iter().enumerate();
        let mut curr_per_ns: PerNs = match path.kind {
            PathKind::DollarCrate(krate) => {
diff --git a/crates/hir_def/src/nameres/tests.rs b/crates/hir_def/src/nameres/tests.rs
index 723481c36..73e3a4702 100644
--- a/crates/hir_def/src/nameres/tests.rs
+++ b/crates/hir_def/src/nameres/tests.rs
@@ -4,11 +4,13 @@ mod macros;
 mod mod_resolution;
 mod diagnostics;
 mod primitives;
+mod block;
 use std::sync::Arc;
 use base_db::{fixture::WithFixture, SourceDatabase};
 use expect_test::{expect, Expect};
+use hir_expand::db::AstDatabase;
 use test_utils::mark;
 use crate::{db::DefDatabase, nameres::*, test_db::TestDB};
@@ -19,12 +21,30 @@ fn compute_crate_def_map(ra_fixture: &str) -> Arc<DefMap> {
    db.crate_def_map(krate)
 }
+fn compute_block_def_map(ra_fixture: &str) -> Arc<DefMap> {
+    let (db, position) = TestDB::with_position(ra_fixture);
+    let module = db.module_for_file(position.file_id);
+    let ast_map = db.ast_id_map(position.file_id.into());
+    let ast = db.parse(position.file_id);
+    let block: ast::BlockExpr =
+        syntax::algo::find_node_at_offset(&ast.syntax_node(), position.offset).unwrap();
+    let block_id = ast_map.ast_id(&block);
+    db.block_def_map(module.krate, InFile::new(position.file_id.into(), block_id))
+}
 fn check(ra_fixture: &str, expect: Expect) {
    let def_map = compute_crate_def_map(ra_fixture);
    let actual = def_map.dump();
    expect.assert_eq(&actual);
 }
+fn check_at(ra_fixture: &str, expect: Expect) {
+    let def_map = compute_block_def_map(ra_fixture);
+    let actual = def_map.dump();
+    expect.assert_eq(&actual);
+}
 #[test]
 fn crate_def_map_smoke_test() {
    check(
diff --git a/crates/hir_def/src/nameres/tests/block.rs b/crates/hir_def/src/nameres/tests/block.rs
new file mode 100644
index 000000000..01d6326a7
--- /dev/null
+++ b/crates/hir_def/src/nameres/tests/block.rs
@@ -0,0 +1,97 @@
+use super::*;
+#[test]
+fn inner_item_smoke() {
+    check_at(
+        r#"
+struct inner {}
+fn outer() {
+    $0
+    fn inner() {}
+}
+"#,
+        expect![[r#"
+            block scope
+            inner: v
+            crate
+            inner: t
+            outer: v
+        "#]],
+    );
+}
+#[test]
+fn use_from_crate() {
+    check_at(
+        r#"
+struct Struct;
+fn outer() {
+    use Struct;
+    use crate::Struct as CrateStruct;
+    use self::Struct as SelfStruct;
+    $0
+}
+"#,
+        expect![[r#"
+            block scope
+            CrateStruct: t v
+            SelfStruct: t v
+            Struct: t v
+            crate
+            Struct: t v
+            outer: v
+        "#]],
+    );
+}
+#[test]
+fn merge_namespaces() {
+    check_at(
+        r#"
+struct name {}
+fn outer() {
+    fn name() {}
+    use name as imported; // should import both `name`s
+    $0
+}
+"#,
+        expect![[r#"
+            block scope
+            imported: t v
+            name: v
+            crate
+            name: t
+            outer: v
+        "#]],
+    );
+}
+#[test]
+fn nested_blocks() {
+    check_at(
+        r#"
+fn outer() {
+    struct inner1 {}
+    fn inner() {
+        use inner1;
+        use outer;
+        fn inner2() {}
+        $0
+    }
+}
+"#,
+        expect![[r#"
+            block scope
+            inner1: t
+            inner2: v
+            outer: v
+            block scope
+            inner: v
+            inner1: t
+            crate
+            outer: v
+        "#]],
+    );
+}
diff --git a/crates/hir_def/src/resolver.rs b/crates/hir_def/src/resolver.rs
index a505bf2be..b2f577649 100644
--- a/crates/hir_def/src/resolver.rs
+++ b/crates/hir_def/src/resolver.rs
@@ -146,6 +146,19 @@ impl Resolver {
        self.resolve_module_path(db, path, BuiltinShadowMode::Module)
    }
+    pub fn resolve_module_path_in_trait_items(
+        &self,
+        db: &dyn DefDatabase,
+        path: &ModPath,
+    ) -> Option<TraitId> {
+        let (item_map, module) = self.module_scope()?;
+        let (module_res, ..) = item_map.resolve_path(db, module, &path, BuiltinShadowMode::Module);
+        match module_res.take_types()? {
+            ModuleDefId::TraitId(it) => Some(it),
+            _ => None,
+        }
+    }
    pub fn resolve_path_in_type_ns(
        &self,
        db: &dyn DefDatabase,
@@ -416,7 +429,7 @@ impl Resolver {
        let mut traits = FxHashSet::default();
        for scope in &self.scopes {
            if let Scope::ModuleScope(m) = scope {
-                if let Some(prelude) = m.crate_def_map.prelude {
+                if let Some(prelude) = m.crate_def_map.prelude() {
                    let prelude_def_map = db.crate_def_map(prelude.krate);
                    traits.extend(prelude_def_map[prelude.local_id].scope.traits());
                }
@@ -446,11 +459,11 @@ impl Resolver {
    pub fn module(&self) -> Option<ModuleId> {
        let (def_map, local_id) = self.module_scope()?;
-        Some(ModuleId { krate: def_map.krate, local_id })
+        Some(ModuleId { krate: def_map.krate(), local_id })
    }
    pub fn krate(&self) -> Option<CrateId> {
-        self.module_scope().map(|t| t.0.krate)
+        self.module_scope().map(|t| t.0.krate())
    }
    pub fn where_predicates_in_scope<'a>(
@@ -509,13 +522,13 @@ impl Scope {
                    seen.insert((name.clone(), scope));
                    f(name.clone(), ScopeDef::PerNs(scope));
                });
-                m.crate_def_map.extern_prelude.iter().for_each(|(name, &def)| {
+                m.crate_def_map.extern_prelude().for_each(|(name, &def)| {
                    f(name.clone(), ScopeDef::PerNs(PerNs::types(def, Visibility::Public)));
                });
                BUILTIN_SCOPE.iter().for_each(|(name, &def)| {
                    f(name.clone(), ScopeDef::PerNs(def));
                });
-                if let Some(prelude) = m.crate_def_map.prelude {
+                if let Some(prelude) = m.crate_def_map.prelude() {
                    let prelude_def_map = db.crate_def_map(prelude.krate);
                    prelude_def_map[prelude.local_id].scope.entries().for_each(|(name, def)| {
                        let seen_tuple = (name.clone(), def);
diff --git a/crates/hir_def/src/test_db.rs b/crates/hir_def/src/test_db.rs
index 574c0201a..4ff219fb7 100644
--- a/crates/hir_def/src/test_db.rs
+++ b/crates/hir_def/src/test_db.rs
@@ -75,7 +75,7 @@ impl TestDB {
    pub(crate) fn module_for_file(&self, file_id: FileId) -> crate::ModuleId {
        for &krate in self.relevant_crates(file_id).iter() {
            let crate_def_map = self.crate_def_map(krate);
-            for (local_id, data) in crate_def_map.modules.iter() {
+            for (local_id, data) in crate_def_map.modules() {
                if data.origin.file_id() == Some(file_id) {
                    return crate::ModuleId { krate, local_id };
                }
@@ -110,7 +110,7 @@ impl TestDB {
        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.iter() {
+            for (module_id, _) in crate_def_map.modules() {
                let file_id = crate_def_map[module_id].origin.file_id();
                files.extend(file_id)
            }
@@ -135,7 +135,7 @@ impl TestDB {
            let crate_def_map = self.crate_def_map(krate);
            let mut sink = DiagnosticSinkBuilder::new().build(&mut cb);
-            for (module_id, module) in crate_def_map.modules.iter() {
+            for (module_id, module) in crate_def_map.modules() {
                crate_def_map.add_diagnostics(self, module_id, &mut sink);
                for decl in module.scope.declarations() {
diff --git a/crates/hir_expand/src/ast_id_map.rs b/crates/hir_expand/src/ast_id_map.rs
index 2401b0cc5..0991fffd8 100644
--- a/crates/hir_expand/src/ast_id_map.rs
+++ b/crates/hir_expand/src/ast_id_map.rs
@@ -13,7 +13,7 @@ use std::{
 };
 use la_arena::{Arena, Idx};
-use syntax::{ast, AstNode, AstPtr, SyntaxNode, SyntaxNodePtr};
+use syntax::{ast, match_ast, AstNode, AstPtr, SyntaxNode, SyntaxNodePtr};
 /// `AstId` points to an AST node in a specific file.
 pub struct FileAstId<N: AstNode> {
@@ -72,12 +72,20 @@ impl AstIdMap {
        // get lower ids then children. That is, adding a new child does not
        // change parent's id. This means that, say, adding a new function to a
        // trait does not change ids of top-level items, which helps caching.
-        bdfs(node, |it| match ast::Item::cast(it) {
+        bdfs(node, |it| {
-            Some(module_item) => {
+            match_ast! {
-                res.alloc(module_item.syntax());
+                match it {
-                true
+                    ast::Item(module_item) => {
+                        res.alloc(module_item.syntax());
+                        true
+                    },
+                    ast::BlockExpr(block) => {
+                        res.alloc(block.syntax());
+                        true
+                    },
+                    _ => false,
+                }
            }
-            None => false,
        });
        res
    }
diff --git a/crates/hir_expand/src/builtin_derive.rs b/crates/hir_expand/src/builtin_derive.rs
index eb257579f..b7f1aae8f 100644
--- a/crates/hir_expand/src/builtin_derive.rs
+++ b/crates/hir_expand/src/builtin_derive.rs
@@ -102,7 +102,7 @@ fn parse_adt(tt: &tt::Subtree) -> Result<BasicAdtInfo, mbe::ExpandError> {
        debug!("name token not found");
        mbe::ExpandError::ConversionError
    })?;
-    let name_token = tt::Ident { id: name_token_id, text: name.text().clone() };
+    let name_token = tt::Ident { id: name_token_id, text: name.text().into() };
    let type_params = params.map_or(0, |type_param_list| type_param_list.type_params().count());
    Ok(BasicAdtInfo { name: name_token, type_params })
 }
diff --git a/crates/hir_expand/src/db.rs b/crates/hir_expand/src/db.rs
index 467516eb7..cb6e23320 100644
--- a/crates/hir_expand/src/db.rs
+++ b/crates/hir_expand/src/db.rs
@@ -173,7 +173,7 @@ fn macro_arg_text(db: &dyn AstDatabase, id: MacroCallId) -> Option<GreenNode> {
    };
    let loc = db.lookup_intern_macro(id);
    let arg = loc.kind.arg(db)?;
-    Some(arg.green().clone())
+    Some(arg.green().to_owned())
 }
 fn macro_arg(db: &dyn AstDatabase, id: MacroCallId) -> Option<Arc<(tt::Subtree, mbe::TokenMap)>> {
diff --git a/crates/hir_expand/src/name.rs b/crates/hir_expand/src/name.rs
index 95d853b6d..d692cec14 100644
--- a/crates/hir_expand/src/name.rs
+++ b/crates/hir_expand/src/name.rs
@@ -38,7 +38,7 @@ impl Name {
    }
    pub fn new_lifetime(lt: &ast::Lifetime) -> Name {
-        Self::new_text(lt.text().clone())
+        Self::new_text(lt.text().into())
    }
    /// Shortcut to create inline plain text name
@@ -47,12 +47,12 @@ impl Name {
    }
    /// Resolve a name from the text of token.
-    fn resolve(raw_text: &SmolStr) -> Name {
+    fn resolve(raw_text: &str) -> Name {
        let raw_start = "r#";
-        if raw_text.as_str().starts_with(raw_start) {
+        if raw_text.starts_with(raw_start) {
            Name::new_text(SmolStr::new(&raw_text[raw_start.len()..]))
        } else {
-            Name::new_text(raw_text.clone())
+            Name::new_text(raw_text.into())
        }
    }
diff --git a/crates/hir_ty/Cargo.toml b/crates/hir_ty/Cargo.toml
index 98434b741..db42a00dc 100644
--- a/crates/hir_ty/Cargo.toml
+++ b/crates/hir_ty/Cargo.toml
@@ -17,9 +17,9 @@ ena = "0.14.0"
 log = "0.4.8"
 rustc-hash = "1.1.0"
 scoped-tls = "1"
-chalk-solve = { version = "0.47", default-features = false }
+chalk-solve = { version = "0.50", default-features = false }
-chalk-ir = "0.47"
+chalk-ir = "0.50"
-chalk-recursive = "0.47"
+chalk-recursive = "0.50"
 la-arena = { version = "0.2.0", path = "../../lib/arena" }
 stdx = { path = "../stdx", version = "0.0.0" }
diff --git a/crates/hir_ty/src/diagnostics.rs b/crates/hir_ty/src/diagnostics.rs
index c67a289f2..247da43f2 100644
--- a/crates/hir_ty/src/diagnostics.rs
+++ b/crates/hir_ty/src/diagnostics.rs
@@ -409,7 +409,7 @@ mod tests {
                let crate_def_map = self.crate_def_map(krate);
                let mut fns = Vec::new();
-                for (module_id, _) in crate_def_map.modules.iter() {
+                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);
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index 9bf3b51b0..d7351d212 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -491,7 +491,10 @@ impl<'a> InferenceContext<'a> {
            Expr::Box { expr } => {
                let inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
                if let Some(box_) = self.resolve_boxed_box() {
-                    Ty::apply_one(TypeCtor::Adt(box_), inner_ty)
+                    let mut sb = Substs::build_for_type_ctor(self.db, TypeCtor::Adt(box_));
+                    sb = sb.push(inner_ty);
+                    sb = sb.fill(repeat_with(|| self.table.new_type_var()));
+                    Ty::apply(TypeCtor::Adt(box_), sb.build())
                } else {
                    Ty::Unknown
                }
diff --git a/crates/hir_ty/src/method_resolution.rs b/crates/hir_ty/src/method_resolution.rs
index 8a289f52a..f06aeeb42 100644
--- a/crates/hir_ty/src/method_resolution.rs
+++ b/crates/hir_ty/src/method_resolution.rs
@@ -112,7 +112,7 @@ impl TraitImpls {
        let mut impls = Self { map: FxHashMap::default() };
        let crate_def_map = db.crate_def_map(krate);
-        for (_module_id, module_data) in crate_def_map.modules.iter() {
+        for (_module_id, module_data) in crate_def_map.modules() {
            for impl_id in module_data.scope.impls() {
                let target_trait = match db.impl_trait(impl_id) {
                    Some(tr) => tr.value.trait_,
@@ -198,7 +198,7 @@ impl InherentImpls {
        let mut map: FxHashMap<_, Vec<_>> = FxHashMap::default();
        let crate_def_map = db.crate_def_map(krate);
-        for (_module_id, module_data) in crate_def_map.modules.iter() {
+        for (_module_id, module_data) in crate_def_map.modules() {
            for impl_id in module_data.scope.impls() {
                let data = db.impl_data(impl_id);
                if data.target_trait.is_some() {
diff --git a/crates/hir_ty/src/test_db.rs b/crates/hir_ty/src/test_db.rs
index 646e16bbe..3bbcbc242 100644
--- a/crates/hir_ty/src/test_db.rs
+++ b/crates/hir_ty/src/test_db.rs
@@ -81,7 +81,7 @@ impl TestDB {
    pub(crate) fn module_for_file(&self, file_id: FileId) -> ModuleId {
        for &krate in self.relevant_crates(file_id).iter() {
            let crate_def_map = self.crate_def_map(krate);
-            for (local_id, data) in crate_def_map.modules.iter() {
+            for (local_id, data) in crate_def_map.modules() {
                if data.origin.file_id() == Some(file_id) {
                    return ModuleId { krate, local_id };
                }
@@ -95,7 +95,7 @@ impl TestDB {
        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.iter() {
+            for (module_id, _) in crate_def_map.modules() {
                let file_id = crate_def_map[module_id].origin.file_id();
                files.extend(file_id)
            }
diff --git a/crates/hir_ty/src/tests/simple.rs b/crates/hir_ty/src/tests/simple.rs
index 8d431b920..16682f76f 100644
--- a/crates/hir_ty/src/tests/simple.rs
+++ b/crates/hir_ty/src/tests/simple.rs
@@ -29,6 +29,30 @@ mod boxed {
 }
 #[test]
+fn infer_box_with_allocator() {
+    check_types(
+        r#"
+//- /main.rs crate:main deps:std
+fn test() {
+    let x = box 1;
+    let t = (x, box x, box &1, box [1]);
+    t;
+} //^ (Box<i32, {unknown}>, Box<Box<i32, {unknown}>, {unknown}>, Box<&i32, {unknown}>, Box<[i32; _], {unknown}>)
+//- /std.rs crate:std
+#[prelude_import] use prelude::*;
+mod boxed {
+    #[lang = "owned_box"]
+    pub struct Box<T: ?Sized, A: Allocator> {
+        inner: *mut T,
+        allocator: A,
+    }
+}
+"#,
+    );
+}
+#[test]
 fn infer_adt_self() {
    check_types(
        r#"
diff --git a/crates/ide/src/display/navigation_target.rs b/crates/ide/src/display/navigation_target.rs
index 8d08e4763..16fa828ad 100644
--- a/crates/ide/src/display/navigation_target.rs
+++ b/crates/ide/src/display/navigation_target.rs
@@ -130,8 +130,7 @@ impl NavigationTarget {
        node: InFile<&dyn ast::NameOwner>,
        kind: SymbolKind,
    ) -> NavigationTarget {
-        let name =
+        let name = node.value.name().map(|it| it.text().into()).unwrap_or_else(|| "_".into());
-            node.value.name().map(|it| it.text().clone()).unwrap_or_else(|| SmolStr::new("_"));
        let focus_range =
            node.value.name().map(|it| node.with_value(it.syntax()).original_file_range(db).range);
        let frange = node.map(|it| it.syntax()).original_file_range(db);
@@ -272,6 +271,7 @@ impl ToNav for hir::Module {
            ModuleSource::Module(node) => {
                (node.syntax(), node.name().map(|it| it.syntax().text_range()))
            }
+            ModuleSource::BlockExpr(node) => (node.syntax(), None),
        };
        let frange = src.with_value(syntax).original_file_range(db);
        NavigationTarget::from_syntax(frange.file_id, name, focus, frange.range, SymbolKind::Module)
diff --git a/crates/ide/src/display/short_label.rs b/crates/ide/src/display/short_label.rs
index 990f740b8..7ac050473 100644
--- a/crates/ide/src/display/short_label.rs
+++ b/crates/ide/src/display/short_label.rs
@@ -53,6 +53,12 @@ impl ShortLabel for ast::SourceFile {
    }
 }
+impl ShortLabel for ast::BlockExpr {
+    fn short_label(&self) -> Option<String> {
+        None
+    }
+}
 impl ShortLabel for ast::TypeAlias {
    fn short_label(&self) -> Option<String> {
        short_label_from_node(self, "type ")
@@ -90,7 +96,7 @@ impl ShortLabel for ast::Variant {
 impl ShortLabel for ast::ConstParam {
    fn short_label(&self) -> Option<String> {
        let mut buf = "const ".to_owned();
-        buf.push_str(self.name()?.text().as_str());
+        buf.push_str(self.name()?.text());
        if let Some(type_ref) = self.ty() {
            format_to!(buf, ": {}", type_ref.syntax());
        }
@@ -117,6 +123,6 @@ where
 {
    let mut buf = node.visibility().map(|v| format!("{} ", v.syntax())).unwrap_or_default();
    buf.push_str(label);
-    buf.push_str(node.name()?.text().as_str());
+    buf.push_str(node.name()?.text());
    Some(buf)
 }
diff --git a/crates/ide/src/doc_links.rs b/crates/ide/src/doc_links.rs
index 1f08d7810..730e0dd0a 100644
--- a/crates/ide/src/doc_links.rs
+++ b/crates/ide/src/doc_links.rs
@@ -221,14 +221,31 @@ fn rewrite_intra_doc_link(
    }?;
    let krate = resolved.module(db)?.krate();
    let canonical_path = resolved.canonical_path(db)?;
-    let new_target = get_doc_url(db, &krate)?
+    let mut new_url = get_doc_url(db, &krate)?
        .join(&format!("{}/", krate.display_name(db)?))
        .ok()?
        .join(&canonical_path.replace("::", "/"))
        .ok()?
        .join(&get_symbol_filename(db, &resolved)?)
-        .ok()?
+        .ok()?;
-        .into_string();
+    if let ModuleDef::Trait(t) = resolved {
+        let items = t.items(db);
+        if let Some(field_or_assoc_item) = items.iter().find_map(|assoc_item| {
+            if let Some(name) = assoc_item.name(db) {
+                if link.to_string() == format!("{}::{}", canonical_path, name) {
+                    return Some(FieldOrAssocItem::AssocItem(*assoc_item));
+                }
+            }
+            None
+        }) {
+            if let Some(fragment) = get_symbol_fragment(db, &field_or_assoc_item) {
+                new_url = new_url.join(&fragment).ok()?;
+            }
+        };
+    }
+    let new_target = new_url.into_string();
    let new_title = strip_prefixes_suffixes(title);
    Some((new_target, new_title.to_string()))
 }
diff --git a/crates/ide/src/extend_selection.rs b/crates/ide/src/extend_selection.rs
index 17a540972..2d722dee0 100644
--- a/crates/ide/src/extend_selection.rs
+++ b/crates/ide/src/extend_selection.rs
@@ -213,8 +213,8 @@ fn extend_ws(root: &SyntaxNode, ws: SyntaxToken, offset: TextSize) -> TextRange
    let ws_text = ws.text();
    let suffix = TextRange::new(offset, ws.text_range().end()) - ws.text_range().start();
    let prefix = TextRange::new(ws.text_range().start(), offset) - ws.text_range().start();
-    let ws_suffix = &ws_text.as_str()[suffix];
+    let ws_suffix = &ws_text[suffix];
-    let ws_prefix = &ws_text.as_str()[prefix];
+    let ws_prefix = &ws_text[prefix];
    if ws_text.contains('\n') && !ws_suffix.contains('\n') {
        if let Some(node) = ws.next_sibling_or_token() {
            let start = match ws_prefix.rfind('\n') {
diff --git a/crates/ide/src/goto_definition.rs b/crates/ide/src/goto_definition.rs
index a1d2bce1d..1a997fa40 100644
--- a/crates/ide/src/goto_definition.rs
+++ b/crates/ide/src/goto_definition.rs
@@ -2,16 +2,14 @@ use either::Either;
 use hir::{HasAttrs, ModuleDef, Semantics};
 use ide_db::{
    defs::{Definition, NameClass, NameRefClass},
-    symbol_index, RootDatabase,
+    RootDatabase,
 };
 use syntax::{
    ast, match_ast, AstNode, AstToken, SyntaxKind::*, SyntaxToken, TextSize, TokenAtOffset, T,
 };
 use crate::{
-    display::{ToNav, TryToNav},
+    display::TryToNav, doc_links::extract_definitions_from_markdown, runnables::doc_owner_to_def,
-    doc_links::extract_definitions_from_markdown,
-    runnables::doc_owner_to_def,
    FilePosition, NavigationTarget, RangeInfo,
 };
@@ -38,28 +36,26 @@ pub(crate) fn goto_definition(
        return Some(RangeInfo::new(original_token.text_range(), vec![nav]));
    }
-    let nav_targets = match_ast! {
+    let nav = match_ast! {
        match parent {
            ast::NameRef(name_ref) => {
-                reference_definition(&sema, Either::Right(&name_ref)).to_vec()
+                reference_definition(&sema, Either::Right(&name_ref))
            },
            ast::Name(name) => {
                let def = NameClass::classify(&sema, &name)?.referenced_or_defined(sema.db);
-                let nav = def.try_to_nav(sema.db)?;
+                def.try_to_nav(sema.db)
-                vec![nav]
            },
            ast::Lifetime(lt) => if let Some(name_class) = NameClass::classify_lifetime(&sema, &lt) {
                let def = name_class.referenced_or_defined(sema.db);
-                let nav = def.try_to_nav(sema.db)?;
+                def.try_to_nav(sema.db)
-                vec![nav]
            } else {
-                reference_definition(&sema, Either::Left(&lt)).to_vec()
+                reference_definition(&sema, Either::Left(&lt))
            },
            _ => return None,
        }
    };
-    Some(RangeInfo::new(original_token.text_range(), nav_targets))
+    Some(RangeInfo::new(original_token.text_range(), nav.into_iter().collect()))
 }
 fn def_for_doc_comment(
@@ -120,42 +116,16 @@ fn pick_best(tokens: TokenAtOffset<SyntaxToken>) -> Option<SyntaxToken> {
    }
 }
-#[derive(Debug)]
-pub(crate) enum ReferenceResult {
-    Exact(NavigationTarget),
-    Approximate(Vec<NavigationTarget>),
-}
-impl ReferenceResult {
-    fn to_vec(self) -> Vec<NavigationTarget> {
-        match self {
-            ReferenceResult::Exact(target) => vec![target],
-            ReferenceResult::Approximate(vec) => vec,
-        }
-    }
-}
 pub(crate) fn reference_definition(
    sema: &Semantics<RootDatabase>,
    name_ref: Either<&ast::Lifetime, &ast::NameRef>,
-) -> ReferenceResult {
+) -> Option<NavigationTarget> {
    let name_kind = name_ref.either(
        |lifetime| NameRefClass::classify_lifetime(sema, lifetime),
        |name_ref| NameRefClass::classify(sema, name_ref),
-    );
+    )?;
-    if let Some(def) = name_kind {
+    let def = name_kind.referenced(sema.db);
-        let def = def.referenced(sema.db);
+    def.try_to_nav(sema.db)
-        return match def.try_to_nav(sema.db) {
-            Some(nav) => ReferenceResult::Exact(nav),
-            None => ReferenceResult::Approximate(Vec::new()),
-        };
-    }
-    // Fallback index based approach:
-    let name = name_ref.either(ast::Lifetime::text, ast::NameRef::text);
-    let navs =
-        symbol_index::index_resolve(sema.db, name).into_iter().map(|s| s.to_nav(sema.db)).collect();
-    ReferenceResult::Approximate(navs)
 }
 #[cfg(test)]
@@ -192,12 +162,12 @@ mod tests {
    fn goto_def_for_extern_crate() {
        check(
            r#"
-            //- /main.rs crate:main deps:std
+//- /main.rs crate:main deps:std
-            extern crate std$0;
+extern crate std$0;
-            //- /std/lib.rs crate:std
+//- /std/lib.rs crate:std
-            // empty
+// empty
-            //^ file
+//^ file
-            "#,
+"#,
        )
    }
@@ -205,12 +175,12 @@ mod tests {
    fn goto_def_for_renamed_extern_crate() {
        check(
            r#"
-            //- /main.rs crate:main deps:std
+//- /main.rs crate:main deps:std
-            extern crate std as abc$0;
+extern crate std as abc$0;
-            //- /std/lib.rs crate:std
+//- /std/lib.rs crate:std
-            // empty
+// empty
-            //^ file
+//^ file
-            "#,
+"#,
        )
    }
@@ -297,13 +267,13 @@ fn bar() {
    fn goto_def_for_macros_from_other_crates() {
        check(
            r#"
-//- /lib.rs
+//- /lib.rs crate:main deps:foo
 use foo::foo;
 fn bar() {
    $0foo!();
 }
-//- /foo/lib.rs
+//- /foo/lib.rs crate:foo
 #[macro_export]
 macro_rules! foo { () => { () } }
           //^^^
@@ -315,10 +285,10 @@ macro_rules! foo { () => { () } }
    fn goto_def_for_macros_in_use_tree() {
        check(
            r#"
-//- /lib.rs
+//- /lib.rs crate:main deps:foo
 use foo::foo$0;
-//- /foo/lib.rs
+//- /foo/lib.rs crate:foo
 #[macro_export]
 macro_rules! foo { () => { () } }
           //^^^
@@ -976,10 +946,10 @@ type Alias<T> = T$0;
    fn goto_def_for_macro_container() {
        check(
            r#"
-//- /lib.rs
+//- /lib.rs crate:main deps:foo
 foo::module$0::mac!();
-//- /foo/lib.rs
+//- /foo/lib.rs crate:foo
 pub mod module {
      //^^^^^^
    #[macro_export]
diff --git a/crates/ide/src/hover.rs b/crates/ide/src/hover.rs
index 44ebdbd35..d47a4cb0f 100644
--- a/crates/ide/src/hover.rs
+++ b/crates/ide/src/hover.rs
@@ -321,6 +321,7 @@ fn hover_for_definition(db: &RootDatabase, def: Definition) -> Option<Markup> {
                match it.definition_source(db).value {
                    ModuleSource::Module(it) => it.short_label(),
                    ModuleSource::SourceFile(it) => it.short_label(),
+                    ModuleSource::BlockExpr(it) => it.short_label(),
                },
                mod_path,
            ),
@@ -1825,6 +1826,35 @@ pub struct B$0ar
            "#]],
        );
    }
+    #[test]
+    fn test_hover_intra_link_reference_to_trait_method() {
+        check(
+            r#"
+pub trait Foo {
+    fn buzz() -> usize;
+}
+/// [Foo][buzz]
+///
+/// [buzz]: Foo::buzz
+pub struct B$0ar
+"#,
+            expect![[r#"
+                *Bar*
+                ```rust
+                test
+                ```
+                ```rust
+                pub struct Bar
+                ```
+                ---
+                [Foo](https://docs.rs/test/*/test/trait.Foo.html#tymethod.buzz)
+            "#]],
+        );
+    }
    #[test]
    fn test_hover_external_url() {
diff --git a/crates/ide/src/inlay_hints.rs b/crates/ide/src/inlay_hints.rs
index a2039fcc7..54485fd30 100644
--- a/crates/ide/src/inlay_hints.rs
+++ b/crates/ide/src/inlay_hints.rs
@@ -411,7 +411,7 @@ fn get_string_representation(expr: &ast::Expr) -> Option<String> {
    match expr {
        ast::Expr::MethodCallExpr(method_call_expr) => {
            let name_ref = method_call_expr.name_ref()?;
-            match name_ref.text().as_str() {
+            match name_ref.text() {
                "clone" => method_call_expr.receiver().map(|rec| rec.to_string()),
                name_ref => Some(name_ref.to_owned()),
            }
diff --git a/crates/ide/src/join_lines.rs b/crates/ide/src/join_lines.rs
index 981467c8d..631bde0f1 100644
--- a/crates/ide/src/join_lines.rs
+++ b/crates/ide/src/join_lines.rs
@@ -59,7 +59,7 @@ fn remove_newline(edit: &mut TextEditBuilder, token: &SyntaxToken, offset: TextS
        // The node is either the first or the last in the file
        let suff = &token.text()[TextRange::new(
            offset - token.text_range().start() + TextSize::of('\n'),
-            TextSize::of(token.text().as_str()),
+            TextSize::of(token.text()),
        )];
        let spaces = suff.bytes().take_while(|&b| b == b' ').count();
diff --git a/crates/ide/src/runnables.rs b/crates/ide/src/runnables.rs
index e282b31af..33170906d 100644
--- a/crates/ide/src/runnables.rs
+++ b/crates/ide/src/runnables.rs
@@ -9,6 +9,7 @@ use syntax::{
    ast::{self, AstNode, AttrsOwner},
    match_ast, SyntaxNode,
 };
+use test_utils::mark;
 use crate::{
    display::{ToNav, TryToNav},
@@ -96,28 +97,26 @@ impl Runnable {
 pub(crate) fn runnables(db: &RootDatabase, file_id: FileId) -> Vec<Runnable> {
    let sema = Semantics::new(db);
    let module = match sema.to_module_def(file_id) {
-        None => return vec![],
+        None => return Vec::new(),
        Some(it) => it,
    };
-    runnables_mod(&sema, module)
+    let mut res = Vec::new();
+    runnables_mod(&sema, &mut res, module);
+    res
 }
-fn runnables_mod(sema: &Semantics<RootDatabase>, module: hir::Module) -> Vec<Runnable> {
+fn runnables_mod(sema: &Semantics<RootDatabase>, acc: &mut Vec<Runnable>, module: hir::Module) {
-    let mut res: Vec<Runnable> = module
+    acc.extend(module.declarations(sema.db).into_iter().filter_map(|def| {
-        .declarations(sema.db)
+        let runnable = match def {
-        .into_iter()
+            hir::ModuleDef::Module(it) => runnable_mod(&sema, it),
-        .filter_map(|def| {
+            hir::ModuleDef::Function(it) => runnable_fn(&sema, it),
-            let runnable = match def {
+            _ => None,
-                hir::ModuleDef::Module(it) => runnable_mod(&sema, it),
+        };
-                hir::ModuleDef::Function(it) => runnable_fn(&sema, it),
+        runnable.or_else(|| module_def_doctest(&sema, def))
-                _ => None,
+    }));
-            };
-            runnable.or_else(|| module_def_doctest(&sema, def))
-        })
-        .collect();
-    res.extend(module.impl_defs(sema.db).into_iter().flat_map(|it| it.items(sema.db)).filter_map(
+    acc.extend(module.impl_defs(sema.db).into_iter().flat_map(|it| it.items(sema.db)).filter_map(
        |def| match def {
            hir::AssocItem::Function(it) => {
                runnable_fn(&sema, it).or_else(|| module_def_doctest(&sema, it.into()))
@@ -127,12 +126,15 @@ fn runnables_mod(sema: &Semantics<RootDatabase>, module: hir::Module) -> Vec<Run
        },
    ));
-    res.extend(module.declarations(sema.db).into_iter().flat_map(|def| match def {
+    for def in module.declarations(sema.db) {
-        hir::ModuleDef::Module(it) => runnables_mod(sema, it),
+        if let hir::ModuleDef::Module(submodule) = def {
-        _ => vec![],
+            match submodule.definition_source(sema.db).value {
-    }));
+                hir::ModuleSource::Module(_) => runnables_mod(sema, acc, submodule),
+                hir::ModuleSource::SourceFile(_) => mark::hit!(dont_recurse_in_outline_submodules),
-    res
+                hir::ModuleSource::BlockExpr(_) => {} // inner items aren't runnable
+            }
+        }
+    }
 }
 pub(crate) fn runnable_fn(sema: &Semantics<RootDatabase>, def: hir::Function) -> Option<Runnable> {
@@ -326,6 +328,7 @@ fn has_test_function_or_multiple_test_submodules(
 #[cfg(test)]
 mod tests {
    use expect_test::{expect, Expect};
+    use test_utils::mark;
    use crate::fixture;
@@ -1050,4 +1053,25 @@ mod tests {
            "#]],
        );
    }
+    #[test]
+    fn dont_recurse_in_outline_submodules() {
+        mark::check!(dont_recurse_in_outline_submodules);
+        check(
+            r#"
+//- /lib.rs
+$0
+mod m;
+//- /m.rs
+mod tests {
+    #[test]
+    fn t() {}
+}
+"#,
+            &[],
+            expect![[r#"
+                []
+            "#]],
+        );
+    }
 }
diff --git a/crates/ide/src/status.rs b/crates/ide/src/status.rs
index e10d7c3a4..137c38c0d 100644
--- a/crates/ide/src/status.rs
+++ b/crates/ide/src/status.rs
@@ -38,6 +38,7 @@ pub(crate) fn status(db: &RootDatabase, file_id: Option<FileId>) -> String {
    format_to!(buf, "{}\n", syntax_tree_stats(db));
    format_to!(buf, "{} (macros)\n", macro_syntax_tree_stats(db));
    format_to!(buf, "{} total\n", memory_usage());
+    format_to!(buf, "\ncounts:\n{}", profile::countme::get_all());
    if let Some(file_id) = file_id {
        format_to!(buf, "\nfile info:\n");
@@ -60,6 +61,7 @@ pub(crate) fn status(db: &RootDatabase, file_id: Option<FileId>) -> String {
            None => format_to!(buf, "does not belong to any crate"),
        }
    }
    buf
 }
diff --git a/crates/ide/src/syntax_highlighting/format.rs b/crates/ide/src/syntax_highlighting/format.rs
index 63bff6376..8c67a0863 100644
--- a/crates/ide/src/syntax_highlighting/format.rs
+++ b/crates/ide/src/syntax_highlighting/format.rs
@@ -31,7 +31,7 @@ fn is_format_string(string: &ast::String) -> Option<()> {
    let parent = string.syntax().parent();
    let name = parent.parent().and_then(ast::MacroCall::cast)?.path()?.segment()?.name_ref()?;
-    if !matches!(name.text().as_str(), "format_args" | "format_args_nl") {
+    if !matches!(name.text(), "format_args" | "format_args_nl") {
        return None;
    }
diff --git a/crates/ide/src/syntax_highlighting/inject.rs b/crates/ide/src/syntax_highlighting/inject.rs
index 281461493..8cdc3688f 100644
--- a/crates/ide/src/syntax_highlighting/inject.rs
+++ b/crates/ide/src/syntax_highlighting/inject.rs
@@ -116,7 +116,7 @@ pub(super) fn doc_comment(hl: &mut Highlights, node: &SyntaxNode) {
            None => (),
        }
-        let line: &str = comment.text().as_str();
+        let line: &str = comment.text();
        let range = comment.syntax().text_range();
        let mut pos = TextSize::of(comment.prefix());
diff --git a/crates/ide_db/src/apply_change.rs b/crates/ide_db/src/apply_change.rs
index c770a236b..9d9b6de7a 100644
--- a/crates/ide_db/src/apply_change.rs
+++ b/crates/ide_db/src/apply_change.rs
@@ -149,6 +149,7 @@ impl RootDatabase {
            // DefDatabase
            hir::db::ItemTreeQuery
+            hir::db::BlockDefMapQuery
            hir::db::CrateDefMapQueryQuery
            hir::db::StructDataQuery
            hir::db::UnionDataQuery
diff --git a/crates/ide_db/src/defs.rs b/crates/ide_db/src/defs.rs
index d9875ffef..a8091dbee 100644
--- a/crates/ide_db/src/defs.rs
+++ b/crates/ide_db/src/defs.rs
@@ -343,7 +343,7 @@ impl NameRefClass {
                        hir::AssocItem::TypeAlias(it) => Some(*it),
                        _ => None,
                    })
-                    .find(|alias| alias.name(sema.db).to_string() == **name_ref.text())
+                    .find(|alias| &alias.name(sema.db).to_string() == name_ref.text())
                {
                    return Some(NameRefClass::Definition(Definition::ModuleDef(
                        ModuleDef::TypeAlias(ty),
diff --git a/crates/ide_db/src/helpers/insert_use.rs b/crates/ide_db/src/helpers/insert_use.rs
index 877d4f1c7..fd4035198 100644
--- a/crates/ide_db/src/helpers/insert_use.rs
+++ b/crates/ide_db/src/helpers/insert_use.rs
@@ -507,7 +507,7 @@ impl ImportGroup {
            PathSegmentKind::SelfKw => ImportGroup::ThisModule,
            PathSegmentKind::SuperKw => ImportGroup::SuperModule,
            PathSegmentKind::CrateKw => ImportGroup::ThisCrate,
-            PathSegmentKind::Name(name) => match name.text().as_str() {
+            PathSegmentKind::Name(name) => match name.text() {
                "std" => ImportGroup::Std,
                "core" => ImportGroup::Std,
                _ => ImportGroup::ExternCrate,
diff --git a/crates/ide_db/src/search.rs b/crates/ide_db/src/search.rs
index 0ecb13a64..b9ba0aed5 100644
--- a/crates/ide_db/src/search.rs
+++ b/crates/ide_db/src/search.rs
@@ -228,6 +228,15 @@ impl Definition {
                            // so do nothing.
                        }
                    }
+                    ModuleSource::BlockExpr(b) => {
+                        if is_first {
+                            let range = Some(b.syntax().text_range());
+                            res.insert(file_id, range);
+                        } else {
+                            // We have already added the enclosing file to the search scope,
+                            // so do nothing.
+                        }
+                    }
                    ModuleSource::SourceFile(_) => {
                        res.insert(file_id, None);
                    }
@@ -257,6 +266,7 @@ impl Definition {
        let mut res = FxHashMap::default();
        let range = match module_src.value {
            ModuleSource::Module(m) => Some(m.syntax().text_range()),
+            ModuleSource::BlockExpr(b) => Some(b.syntax().text_range()),
            ModuleSource::SourceFile(_) => None,
        };
        res.insert(file_id, range);
diff --git a/crates/ide_db/src/symbol_index.rs b/crates/ide_db/src/symbol_index.rs
index 0aa6a0765..e954bd72e 100644
--- a/crates/ide_db/src/symbol_index.rs
+++ b/crates/ide_db/src/symbol_index.rs
@@ -191,7 +191,7 @@ pub fn crate_symbols(db: &RootDatabase, krate: CrateId, query: Query) -> Vec<Fil
    let def_map = db.crate_def_map(krate);
    let mut files = Vec::new();
-    let mut modules = vec![def_map.root];
+    let mut modules = vec![def_map.root()];
    while let Some(module) = modules.pop() {
        let data = &def_map[module];
        files.extend(data.origin.file_id());
@@ -209,7 +209,7 @@ pub fn crate_symbols(db: &RootDatabase, krate: CrateId, query: Query) -> Vec<Fil
    query.search(&buf)
 }
-pub fn index_resolve(db: &RootDatabase, name: &SmolStr) -> Vec<FileSymbol> {
+pub fn index_resolve(db: &RootDatabase, name: &str) -> Vec<FileSymbol> {
    let mut query = Query::new(name.to_string());
    query.exact();
    query.limit(4);
@@ -409,7 +409,7 @@ fn to_symbol(node: &SyntaxNode) -> Option<(SmolStr, SyntaxNodePtr, TextRange)> {
    fn decl<N: NameOwner>(node: N) -> Option<(SmolStr, SyntaxNodePtr, TextRange)> {
        let name = node.name()?;
        let name_range = name.syntax().text_range();
-        let name = name.text().clone();
+        let name = name.text().into();
        let ptr = SyntaxNodePtr::new(node.syntax());
        Some((name, ptr, name_range))
diff --git a/crates/mbe/src/syntax_bridge.rs b/crates/mbe/src/syntax_bridge.rs
index 51002e7b8..0cdc175be 100644
--- a/crates/mbe/src/syntax_bridge.rs
+++ b/crates/mbe/src/syntax_bridge.rs
@@ -507,7 +507,7 @@ impl SrcToken for SynToken {
        }
    }
    fn to_text(&self) -> SmolStr {
-        self.token().text().clone()
+        self.token().text().into()
    }
 }
@@ -682,10 +682,8 @@ impl<'a> TreeSink for TtTreeSink<'a> {
            self.text_pos += TextSize::of(text);
        }
-        let text = SmolStr::new(self.buf.as_str());
+        self.inner.token(kind, self.buf.as_str());
        self.buf.clear();
-        self.inner.token(kind, text);
        // Add whitespace between adjoint puncts
        let next = last.bump();
        if let (
diff --git a/crates/profile/Cargo.toml b/crates/profile/Cargo.toml
index f7231c2b8..cc7da27f7 100644
--- a/crates/profile/Cargo.toml
+++ b/crates/profile/Cargo.toml
@@ -14,6 +14,7 @@ once_cell = "1.3.1"
 cfg-if = "1"
 libc = "0.2.73"
 la-arena = { version = "0.2.0", path = "../../lib/arena" }
+countme = { version = "2.0.0-pre.2", features = ["enable"] }
 jemalloc-ctl = { version = "0.3.3", optional = true }
 [target.'cfg(target_os = "linux")'.dependencies]
diff --git a/crates/profile/src/hprof.rs b/crates/profile/src/hprof.rs
index 8957ea016..29d2ed518 100644
--- a/crates/profile/src/hprof.rs
+++ b/crates/profile/src/hprof.rs
@@ -3,6 +3,7 @@ use once_cell::sync::Lazy;
 use std::{
    cell::RefCell,
    collections::{BTreeMap, HashSet},
+    env,
    io::{stderr, Write},
    sync::{
        atomic::{AtomicBool, Ordering},
@@ -18,7 +19,8 @@ use crate::tree::{Idx, Tree};
 /// env RA_PROFILE=foo|bar|baz   // enabled only selected entries
 /// env RA_PROFILE=*@3>10        // dump everything, up to depth 3, if it takes more than 10 ms
 pub fn init() {
-    let spec = std::env::var("RA_PROFILE").unwrap_or_default();
+    countme::enable(env::var("RA_COUNT").is_ok());
+    let spec = env::var("RA_PROFILE").unwrap_or_default();
    init_from(&spec);
 }
diff --git a/crates/profile/src/lib.rs b/crates/profile/src/lib.rs
index aa6ccc36c..79dba47d5 100644
--- a/crates/profile/src/lib.rs
+++ b/crates/profile/src/lib.rs
@@ -15,6 +15,13 @@ pub use crate::{
    stop_watch::{StopWatch, StopWatchSpan},
 };
+pub use countme;
+/// Include `_c: Count<Self>` field in important structs to count them.
+///
+/// To view the counts, run with `RA_COUNT=1`. The overhead of disabled count is
+/// almost zero.
+pub use countme::Count;
 thread_local!(static IN_SCOPE: RefCell<bool> = RefCell::new(false));
 /// Allows to check if the current code is withing some dynamic scope, can be
diff --git a/crates/project_model/src/build_data.rs b/crates/project_model/src/build_data.rs
new file mode 100644
index 000000000..cf32995e0
--- /dev/null
+++ b/crates/project_model/src/build_data.rs
@@ -0,0 +1,206 @@
+//! Handles build script specific information
+use std::{
+    ffi::OsStr,
+    io::BufReader,
+    path::{Path, PathBuf},
+    process::{Command, Stdio},
+};
+use anyhow::Result;
+use cargo_metadata::{BuildScript, Message, Package, PackageId};
+use itertools::Itertools;
+use paths::{AbsPath, AbsPathBuf};
+use rustc_hash::FxHashMap;
+use stdx::JodChild;
+use crate::{cfg_flag::CfgFlag, CargoConfig};
+#[derive(Debug, Clone, Default)]
+pub(crate) struct BuildDataMap {
+    data: FxHashMap<PackageId, BuildData>,
+}
+#[derive(Debug, Clone, Default, PartialEq, Eq)]
+pub struct BuildData {
+    /// List of config flags defined by this package's build script
+    pub cfgs: Vec<CfgFlag>,
+    /// List of cargo-related environment variables with their value
+    ///
+    /// If the package has a build script which defines environment variables,
+    /// they can also be found here.
+    pub envs: Vec<(String, String)>,
+    /// Directory where a build script might place its output
+    pub out_dir: Option<AbsPathBuf>,
+    /// Path to the proc-macro library file if this package exposes proc-macros
+    pub proc_macro_dylib_path: Option<AbsPathBuf>,
+}
+impl BuildDataMap {
+    pub(crate) fn new(
+        cargo_toml: &AbsPath,
+        cargo_features: &CargoConfig,
+        packages: &Vec<Package>,
+        progress: &dyn Fn(String),
+    ) -> Result<BuildDataMap> {
+        let mut cmd = Command::new(toolchain::cargo());
+        cmd.args(&["check", "--workspace", "--message-format=json", "--manifest-path"])
+            .arg(cargo_toml.as_ref());
+        // --all-targets includes tests, benches and examples in addition to the
+        // default lib and bins. This is an independent concept from the --targets
+        // flag below.
+        cmd.arg("--all-targets");
+        if let Some(target) = &cargo_features.target {
+            cmd.args(&["--target", target]);
+        }
+        if cargo_features.all_features {
+            cmd.arg("--all-features");
+        } else {
+            if cargo_features.no_default_features {
+                // FIXME: `NoDefaultFeatures` is mutual exclusive with `SomeFeatures`
+                // https://github.com/oli-obk/cargo_metadata/issues/79
+                cmd.arg("--no-default-features");
+            }
+            if !cargo_features.features.is_empty() {
+                cmd.arg("--features");
+                cmd.arg(cargo_features.features.join(" "));
+            }
+        }
+        cmd.stdout(Stdio::piped()).stderr(Stdio::null()).stdin(Stdio::null());
+        let mut child = cmd.spawn().map(JodChild)?;
+        let child_stdout = child.stdout.take().unwrap();
+        let stdout = BufReader::new(child_stdout);
+        let mut res = BuildDataMap::default();
+        for message in cargo_metadata::Message::parse_stream(stdout) {
+            if let Ok(message) = message {
+                match message {
+                    Message::BuildScriptExecuted(BuildScript {
+                        package_id,
+                        out_dir,
+                        cfgs,
+                        env,
+                        ..
+                    }) => {
+                        let cfgs = {
+                            let mut acc = Vec::new();
+                            for cfg in cfgs {
+                                match cfg.parse::<CfgFlag>() {
+                                    Ok(it) => acc.push(it),
+                                    Err(err) => {
+                                        anyhow::bail!("invalid cfg from cargo-metadata: {}", err)
+                                    }
+                                };
+                            }
+                            acc
+                        };
+                        let res = res.data.entry(package_id.clone()).or_default();
+                        // cargo_metadata crate returns default (empty) path for
+                        // older cargos, which is not absolute, so work around that.
+                        if out_dir != PathBuf::default() {
+                            let out_dir = AbsPathBuf::assert(out_dir);
+                            res.out_dir = Some(out_dir);
+                            res.cfgs = cfgs;
+                        }
+                        res.envs = env;
+                    }
+                    Message::CompilerArtifact(message) => {
+                        progress(format!("metadata {}", message.target.name));
+                        if message.target.kind.contains(&"proc-macro".to_string()) {
+                            let package_id = message.package_id;
+                            // Skip rmeta file
+                            if let Some(filename) =
+                                message.filenames.iter().find(|name| is_dylib(name))
+                            {
+                                let filename = AbsPathBuf::assert(filename.clone());
+                                let res = res.data.entry(package_id.clone()).or_default();
+                                res.proc_macro_dylib_path = Some(filename);
+                            }
+                        }
+                    }
+                    Message::CompilerMessage(message) => {
+                        progress(message.target.name.clone());
+                    }
+                    Message::Unknown => (),
+                    Message::BuildFinished(_) => {}
+                    Message::TextLine(_) => {}
+                }
+            }
+        }
+        res.inject_cargo_env(packages);
+        Ok(res)
+    }
+    pub(crate) fn with_cargo_env(packages: &Vec<Package>) -> Self {
+        let mut res = Self::default();
+        res.inject_cargo_env(packages);
+        res
+    }
+    pub(crate) fn get(&self, id: &PackageId) -> Option<&BuildData> {
+        self.data.get(id)
+    }
+    fn inject_cargo_env(&mut self, packages: &Vec<Package>) {
+        for meta_pkg in packages {
+            let resource = self.data.entry(meta_pkg.id.clone()).or_default();
+            inject_cargo_env(meta_pkg, &mut resource.envs);
+            if let Some(out_dir) = &resource.out_dir {
+                // NOTE: cargo and rustc seem to hide non-UTF-8 strings from env! and option_env!()
+                if let Some(out_dir) = out_dir.to_str().map(|s| s.to_owned()) {
+                    resource.envs.push(("OUT_DIR".to_string(), out_dir));
+                }
+            }
+        }
+    }
+}
+// FIXME: File a better way to know if it is a dylib
+fn is_dylib(path: &Path) -> bool {
+    match path.extension().and_then(OsStr::to_str).map(|it| it.to_string().to_lowercase()) {
+        None => false,
+        Some(ext) => matches!(ext.as_str(), "dll" | "dylib" | "so"),
+    }
+}
+/// Recreates the compile-time environment variables that Cargo sets.
+///
+/// Should be synced with <https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-crates>
+fn inject_cargo_env(package: &cargo_metadata::Package, env: &mut Vec<(String, String)>) {
+    // FIXME: Missing variables:
+    // CARGO, CARGO_PKG_HOMEPAGE, CARGO_CRATE_NAME, CARGO_BIN_NAME, CARGO_BIN_EXE_<name>
+    let mut manifest_dir = package.manifest_path.clone();
+    manifest_dir.pop();
+    if let Some(cargo_manifest_dir) = manifest_dir.to_str() {
+        env.push(("CARGO_MANIFEST_DIR".into(), cargo_manifest_dir.into()));
+    }
+    env.push(("CARGO_PKG_VERSION".into(), package.version.to_string()));
+    env.push(("CARGO_PKG_VERSION_MAJOR".into(), package.version.major.to_string()));
+    env.push(("CARGO_PKG_VERSION_MINOR".into(), package.version.minor.to_string()));
+    env.push(("CARGO_PKG_VERSION_PATCH".into(), package.version.patch.to_string()));
+    let pre = package.version.pre.iter().map(|id| id.to_string()).format(".");
+    env.push(("CARGO_PKG_VERSION_PRE".into(), pre.to_string()));
+    let authors = package.authors.join(";");
+    env.push(("CARGO_PKG_AUTHORS".into(), authors));
+    env.push(("CARGO_PKG_NAME".into(), package.name.clone()));
+    env.push(("CARGO_PKG_DESCRIPTION".into(), package.description.clone().unwrap_or_default()));
+    //env.push(("CARGO_PKG_HOMEPAGE".into(), package.homepage.clone().unwrap_or_default()));
+    env.push(("CARGO_PKG_REPOSITORY".into(), package.repository.clone().unwrap_or_default()));
+    env.push(("CARGO_PKG_LICENSE".into(), package.license.clone().unwrap_or_default()));
+    let license_file =
+        package.license_file.as_ref().map(|buf| buf.display().to_string()).unwrap_or_default();
+    env.push(("CARGO_PKG_LICENSE_FILE".into(), license_file));
+}
diff --git a/crates/project_model/src/cargo_workspace.rs b/crates/project_model/src/cargo_workspace.rs
index c0ed37fc1..c8a5333c4 100644
--- a/crates/project_model/src/cargo_workspace.rs
+++ b/crates/project_model/src/cargo_workspace.rs
@@ -1,24 +1,15 @@
 //! FIXME: write short doc here
-use std::{
+use std::{convert::TryInto, ops, process::Command};
-    convert::TryInto,
-    ffi::OsStr,
-    io::BufReader,
-    ops,
-    path::{Path, PathBuf},
-    process::{Command, Stdio},
-};
 use anyhow::{Context, Result};
 use base_db::Edition;
-use cargo_metadata::{BuildScript, CargoOpt, Message, MetadataCommand, PackageId};
+use cargo_metadata::{CargoOpt, MetadataCommand};
-use itertools::Itertools;
 use la_arena::{Arena, Idx};
 use paths::{AbsPath, AbsPathBuf};
 use rustc_hash::FxHashMap;
-use stdx::JodChild;
-use crate::cfg_flag::CfgFlag;
+use crate::build_data::{BuildData, BuildDataMap};
 use crate::utf8_stdout;
 /// `CargoWorkspace` represents the logical structure of, well, a Cargo
@@ -99,19 +90,12 @@ pub struct PackageData {
    pub dependencies: Vec<PackageDependency>,
    /// Rust edition for this package
    pub edition: Edition,
-    /// List of features to activate
+    /// Features provided by the crate, mapped to the features required by that feature.
-    pub features: Vec<String>,
+    pub features: FxHashMap<String, Vec<String>>,
-    /// List of config flags defined by this package's build script
+    /// List of features enabled on this package
-    pub cfgs: Vec<CfgFlag>,
+    pub active_features: Vec<String>,
-    /// List of cargo-related environment variables with their value
+    /// Build script related data for this package
-    ///
+    pub build_data: BuildData,
-    /// If the package has a build script which defines environment variables,
-    /// they can also be found here.
-    pub envs: Vec<(String, String)>,
-    /// Directory where a build script might place its output
-    pub out_dir: Option<AbsPathBuf>,
-    /// Path to the proc-macro library file if this package exposes proc-macros
-    pub proc_macro_dylib_path: Option<AbsPathBuf>,
 }
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -244,17 +228,11 @@ impl CargoWorkspace {
            )
        })?;
-        let mut out_dir_by_id = FxHashMap::default();
+        let resources = if config.load_out_dirs_from_check {
-        let mut cfgs = FxHashMap::default();
+            BuildDataMap::new(cargo_toml, config, &meta.packages, progress)?
-        let mut envs = FxHashMap::default();
+        } else {
-        let mut proc_macro_dylib_paths = FxHashMap::default();
+            BuildDataMap::with_cargo_env(&meta.packages)
-        if config.load_out_dirs_from_check {
+        };
-            let resources = load_extern_resources(cargo_toml, config, progress)?;
-            out_dir_by_id = resources.out_dirs;
-            cfgs = resources.cfgs;
-            envs = resources.env;
-            proc_macro_dylib_paths = resources.proc_dylib_paths;
-        }
        let mut pkg_by_id = FxHashMap::default();
        let mut packages = Arena::default();
@@ -265,7 +243,7 @@ impl CargoWorkspace {
        meta.packages.sort_by(|a, b| a.id.cmp(&b.id));
        for meta_pkg in meta.packages {
            let id = meta_pkg.id.clone();
-            inject_cargo_env(&meta_pkg, envs.entry(id).or_default());
+            let build_data = resources.get(&id).cloned().unwrap_or_default();
            let cargo_metadata::Package { id, edition, name, manifest_path, version, .. } =
                meta_pkg;
@@ -281,11 +259,9 @@ impl CargoWorkspace {
                is_member,
                edition,
                dependencies: Vec::new(),
-                features: Vec::new(),
+                features: meta_pkg.features.into_iter().collect(),
-                cfgs: cfgs.get(&id).cloned().unwrap_or_default(),
+                active_features: Vec::new(),
-                envs: envs.get(&id).cloned().unwrap_or_default(),
+                build_data,
-                out_dir: out_dir_by_id.get(&id).cloned(),
-                proc_macro_dylib_path: proc_macro_dylib_paths.get(&id).cloned(),
            });
            let pkg_data = &mut packages[pkg];
            pkg_by_id.insert(id, pkg);
@@ -328,7 +304,7 @@ impl CargoWorkspace {
                let dep = PackageDependency { name: dep_node.name, pkg };
                packages[source].dependencies.push(dep);
            }
-            packages[source].features.extend(node.features);
+            packages[source].active_features.extend(node.features);
        }
        let workspace_root = AbsPathBuf::assert(meta.workspace_root);
@@ -362,149 +338,3 @@ impl CargoWorkspace {
        self.packages.iter().filter(|(_, v)| v.name == name).count() == 1
    }
 }
-#[derive(Debug, Clone, Default)]
-pub(crate) struct ExternResources {
-    out_dirs: FxHashMap<PackageId, AbsPathBuf>,
-    proc_dylib_paths: FxHashMap<PackageId, AbsPathBuf>,
-    cfgs: FxHashMap<PackageId, Vec<CfgFlag>>,
-    env: FxHashMap<PackageId, Vec<(String, String)>>,
-}
-pub(crate) fn load_extern_resources(
-    cargo_toml: &Path,
-    cargo_features: &CargoConfig,
-    progress: &dyn Fn(String),
-) -> Result<ExternResources> {
-    let mut cmd = Command::new(toolchain::cargo());
-    cmd.args(&["check", "--workspace", "--message-format=json", "--manifest-path"]).arg(cargo_toml);
-    // --all-targets includes tests, benches and examples in addition to the
-    // default lib and bins. This is an independent concept from the --targets
-    // flag below.
-    cmd.arg("--all-targets");
-    if let Some(target) = &cargo_features.target {
-        cmd.args(&["--target", target]);
-    }
-    if cargo_features.all_features {
-        cmd.arg("--all-features");
-    } else {
-        if cargo_features.no_default_features {
-            // FIXME: `NoDefaultFeatures` is mutual exclusive with `SomeFeatures`
-            // https://github.com/oli-obk/cargo_metadata/issues/79
-            cmd.arg("--no-default-features");
-        }
-        if !cargo_features.features.is_empty() {
-            cmd.arg("--features");
-            cmd.arg(cargo_features.features.join(" "));
-        }
-    }
-    cmd.stdout(Stdio::piped()).stderr(Stdio::null()).stdin(Stdio::null());
-    let mut child = cmd.spawn().map(JodChild)?;
-    let child_stdout = child.stdout.take().unwrap();
-    let stdout = BufReader::new(child_stdout);
-    let mut res = ExternResources::default();
-    for message in cargo_metadata::Message::parse_stream(stdout) {
-        if let Ok(message) = message {
-            match message {
-                Message::BuildScriptExecuted(BuildScript {
-                    package_id,
-                    out_dir,
-                    cfgs,
-                    env,
-                    ..
-                }) => {
-                    let cfgs = {
-                        let mut acc = Vec::new();
-                        for cfg in cfgs {
-                            match cfg.parse::<CfgFlag>() {
-                                Ok(it) => acc.push(it),
-                                Err(err) => {
-                                    anyhow::bail!("invalid cfg from cargo-metadata: {}", err)
-                                }
-                            };
-                        }
-                        acc
-                    };
-                    // cargo_metadata crate returns default (empty) path for
-                    // older cargos, which is not absolute, so work around that.
-                    if out_dir != PathBuf::default() {
-                        let out_dir = AbsPathBuf::assert(out_dir);
-                        res.out_dirs.insert(package_id.clone(), out_dir);
-                        res.cfgs.insert(package_id.clone(), cfgs);
-                    }
-                    res.env.insert(package_id, env);
-                }
-                Message::CompilerArtifact(message) => {
-                    progress(format!("metadata {}", message.target.name));
-                    if message.target.kind.contains(&"proc-macro".to_string()) {
-                        let package_id = message.package_id;
-                        // Skip rmeta file
-                        if let Some(filename) = message.filenames.iter().find(|name| is_dylib(name))
-                        {
-                            let filename = AbsPathBuf::assert(filename.clone());
-                            res.proc_dylib_paths.insert(package_id, filename);
-                        }
-                    }
-                }
-                Message::CompilerMessage(message) => {
-                    progress(message.target.name.clone());
-                }
-                Message::Unknown => (),
-                Message::BuildFinished(_) => {}
-                Message::TextLine(_) => {}
-            }
-        }
-    }
-    Ok(res)
-}
-// FIXME: File a better way to know if it is a dylib
-fn is_dylib(path: &Path) -> bool {
-    match path.extension().and_then(OsStr::to_str).map(|it| it.to_string().to_lowercase()) {
-        None => false,
-        Some(ext) => matches!(ext.as_str(), "dll" | "dylib" | "so"),
-    }
-}
-/// Recreates the compile-time environment variables that Cargo sets.
-///
-/// Should be synced with <https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-crates>
-fn inject_cargo_env(package: &cargo_metadata::Package, env: &mut Vec<(String, String)>) {
-    // FIXME: Missing variables:
-    // CARGO, CARGO_PKG_HOMEPAGE, CARGO_CRATE_NAME, CARGO_BIN_NAME, CARGO_BIN_EXE_<name>
-    let mut manifest_dir = package.manifest_path.clone();
-    manifest_dir.pop();
-    if let Some(cargo_manifest_dir) = manifest_dir.to_str() {
-        env.push(("CARGO_MANIFEST_DIR".into(), cargo_manifest_dir.into()));
-    }
-    env.push(("CARGO_PKG_VERSION".into(), package.version.to_string()));
-    env.push(("CARGO_PKG_VERSION_MAJOR".into(), package.version.major.to_string()));
-    env.push(("CARGO_PKG_VERSION_MINOR".into(), package.version.minor.to_string()));
-    env.push(("CARGO_PKG_VERSION_PATCH".into(), package.version.patch.to_string()));
-    let pre = package.version.pre.iter().map(|id| id.to_string()).format(".");
-    env.push(("CARGO_PKG_VERSION_PRE".into(), pre.to_string()));
-    let authors = package.authors.join(";");
-    env.push(("CARGO_PKG_AUTHORS".into(), authors));
-    env.push(("CARGO_PKG_NAME".into(), package.name.clone()));
-    env.push(("CARGO_PKG_DESCRIPTION".into(), package.description.clone().unwrap_or_default()));
-    //env.push(("CARGO_PKG_HOMEPAGE".into(), package.homepage.clone().unwrap_or_default()));
-    env.push(("CARGO_PKG_REPOSITORY".into(), package.repository.clone().unwrap_or_default()));
-    env.push(("CARGO_PKG_LICENSE".into(), package.license.clone().unwrap_or_default()));
-    let license_file =
-        package.license_file.as_ref().map(|buf| buf.display().to_string()).unwrap_or_default();
-    env.push(("CARGO_PKG_LICENSE_FILE".into(), license_file));
-}
diff --git a/crates/project_model/src/lib.rs b/crates/project_model/src/lib.rs
index 970a7e140..525c336e6 100644
--- a/crates/project_model/src/lib.rs
+++ b/crates/project_model/src/lib.rs
@@ -6,6 +6,7 @@ mod project_json;
 mod sysroot;
 mod workspace;
 mod rustc_cfg;
+mod build_data;
 use std::{
    fs::{read_dir, ReadDir},
diff --git a/crates/project_model/src/workspace.rs b/crates/project_model/src/workspace.rs
index 8e0481ae9..bc5041e5a 100644
--- a/crates/project_model/src/workspace.rs
+++ b/crates/project_model/src/workspace.rs
@@ -178,7 +178,7 @@ impl ProjectWorkspace {
                    let pkg_root = cargo[pkg].root().to_path_buf();
                    let mut include = vec![pkg_root.clone()];
-                    include.extend(cargo[pkg].out_dir.clone());
+                    include.extend(cargo[pkg].build_data.out_dir.clone());
                    let mut exclude = vec![pkg_root.join(".git")];
                    if is_member {
@@ -481,26 +481,24 @@ fn add_target_crate_root(
    let edition = pkg.edition;
    let cfg_options = {
        let mut opts = cfg_options.clone();
-        for feature in pkg.features.iter() {
+        for feature in pkg.active_features.iter() {
            opts.insert_key_value("feature".into(), feature.into());
        }
-        opts.extend(pkg.cfgs.iter().cloned());
+        opts.extend(pkg.build_data.cfgs.iter().cloned());
        opts
    };
    let mut env = Env::default();
-    for (k, v) in &pkg.envs {
+    for (k, v) in &pkg.build_data.envs {
        env.set(k, v.clone());
    }
-    if let Some(out_dir) = &pkg.out_dir {
-        // NOTE: cargo and rustc seem to hide non-UTF-8 strings from env! and option_env!()
-        if let Some(out_dir) = out_dir.to_str().map(|s| s.to_owned()) {
-            env.set("OUT_DIR", out_dir);
-        }
-    }
-    let proc_macro =
+    let proc_macro = pkg
-        pkg.proc_macro_dylib_path.as_ref().map(|it| proc_macro_loader(&it)).unwrap_or_default();
+        .build_data
+        .proc_macro_dylib_path
+        .as_ref()
+        .map(|it| proc_macro_loader(&it))
+        .unwrap_or_default();
    let display_name = CrateDisplayName::from_canonical_name(pkg.name.clone());
    let crate_id = crate_graph.add_crate_root(
diff --git a/crates/rust-analyzer/Cargo.toml b/crates/rust-analyzer/Cargo.toml
index 3cb45b030..268c00942 100644
--- a/crates/rust-analyzer/Cargo.toml
+++ b/crates/rust-analyzer/Cargo.toml
@@ -24,7 +24,7 @@ jod-thread = "0.1.0"
 log = "0.4.8"
 lsp-types = { version = "0.86.0", features = ["proposed"] }
 parking_lot = "0.11.0"
-pico-args = "0.3.1"
+pico-args = "0.4.0"
 oorandom = "11.1.2"
 rustc-hash = "1.1.0"
 serde = { version = "1.0.106", features = ["derive"] }
diff --git a/crates/rust-analyzer/src/bin/args.rs b/crates/rust-analyzer/src/bin/args.rs
index 0a471154e..7d917946e 100644
--- a/crates/rust-analyzer/src/bin/args.rs
+++ b/crates/rust-analyzer/src/bin/args.rs
@@ -109,7 +109,7 @@ impl Args {
        let mut matches = Arguments::from_env();
        if matches.contains("--version") {
-            matches.finish()?;
+            finish_args(matches)?;
            return Ok(Args {
                verbosity: Verbosity::Normal,
                log_file: None,
@@ -143,7 +143,7 @@ impl Args {
        let subcommand = match matches.subcommand()? {
            Some(it) => it,
            None => {
-                matches.finish()?;
+                finish_args(matches)?;
                return Ok(Args { verbosity, log_file, command: Command::RunServer });
            }
        };
@@ -160,7 +160,7 @@ impl Args {
                load_output_dirs: matches.contains("--load-output-dirs"),
                with_proc_macro: matches.contains("--with-proc-macro"),
                path: matches
-                    .free_from_str()?
+                    .opt_free_from_str()?
                    .ok_or_else(|| format_err!("expected positional argument"))?,
            }),
            "analysis-bench" => Command::Bench(BenchCmd {
@@ -187,21 +187,21 @@ impl Args {
                load_output_dirs: matches.contains("--load-output-dirs"),
                with_proc_macro: matches.contains("--with-proc-macro"),
                path: matches
-                    .free_from_str()?
+                    .opt_free_from_str()?
                    .ok_or_else(|| format_err!("expected positional argument"))?,
            }),
            "diagnostics" => Command::Diagnostics {
                load_output_dirs: matches.contains("--load-output-dirs"),
                with_proc_macro: matches.contains("--with-proc-macro"),
                path: matches
-                    .free_from_str()?
+                    .opt_free_from_str()?
                    .ok_or_else(|| format_err!("expected positional argument"))?,
            },
            "proc-macro" => Command::ProcMacro,
            "ssr" => Command::Ssr {
                rules: {
                    let mut acc = Vec::new();
-                    while let Some(rule) = matches.free_from_str()? {
+                    while let Some(rule) = matches.opt_free_from_str()? {
                        acc.push(rule);
                    }
                    acc
@@ -211,7 +211,7 @@ impl Args {
                debug_snippet: matches.opt_value_from_str("--debug")?,
                patterns: {
                    let mut acc = Vec::new();
-                    while let Some(rule) = matches.free_from_str()? {
+                    while let Some(rule) = matches.opt_free_from_str()? {
                        acc.push(rule);
                    }
                    acc
@@ -222,7 +222,14 @@ impl Args {
                return Ok(Args { verbosity, log_file: None, command: Command::Help });
            }
        };
-        matches.finish()?;
+        finish_args(matches)?;
        Ok(Args { verbosity, log_file, command })
    }
 }
+fn finish_args(args: Arguments) -> Result<()> {
+    if !args.finish().is_empty() {
+        bail!("Unused arguments.");
+    }
+    Ok(())
+}
diff --git a/crates/rust-analyzer/src/cli/analysis_stats.rs b/crates/rust-analyzer/src/cli/analysis_stats.rs
index fd1407e60..66416f709 100644
--- a/crates/rust-analyzer/src/cli/analysis_stats.rs
+++ b/crates/rust-analyzer/src/cli/analysis_stats.rs
@@ -2,6 +2,7 @@
 //! errors.
 use std::{
+    env,
    path::PathBuf,
    time::{SystemTime, UNIX_EPOCH},
 };
@@ -295,6 +296,10 @@ impl AnalysisStatsCmd {
            report_metric("total memory", memory.allocated.megabytes() as u64, "MB");
        }
+        if env::var("RA_COUNT").is_ok() {
+            eprintln!("{}", profile::countme::get_all());
+        }
        if self.memory_usage && verbosity.is_verbose() {
            print_memory_usage(host, vfs);
        }
diff --git a/crates/rust-analyzer/src/handlers.rs b/crates/rust-analyzer/src/handlers.rs
index 10cbd7eeb..809452e6d 100644
--- a/crates/rust-analyzer/src/handlers.rs
+++ b/crates/rust-analyzer/src/handlers.rs
@@ -859,6 +859,23 @@ pub(crate) fn handle_formatting(
        RustfmtConfig::Rustfmt { extra_args } => {
            let mut cmd = process::Command::new(toolchain::rustfmt());
            cmd.args(extra_args);
+            // try to chdir to the file so we can respect `rustfmt.toml`
+            // FIXME: use `rustfmt --config-path` once
+            // https://github.com/rust-lang/rustfmt/issues/4660 gets fixed
+            match params.text_document.uri.to_file_path() {
+                Ok(mut path) => {
+                    // pop off file name
+                    if path.pop() && path.is_dir() {
+                        cmd.current_dir(path);
+                    }
+                }
+                Err(_) => {
+                    log::error!(
+                        "Unable to get file path for {}, rustfmt.toml might be ignored",
+                        params.text_document.uri
+                    );
+                }
+            }
            if let Some(&crate_id) = crate_ids.first() {
                // Assume all crates are in the same edition
                let edition = snap.analysis.crate_edition(crate_id)?;
diff --git a/crates/ssr/src/matching.rs b/crates/ssr/src/matching.rs
index 42d313f91..df013bae9 100644
--- a/crates/ssr/src/matching.rs
+++ b/crates/ssr/src/matching.rs
@@ -10,8 +10,11 @@ use hir::Semantics;
 use ide_db::base_db::FileRange;
 use rustc_hash::FxHashMap;
 use std::{cell::Cell, iter::Peekable};
-use syntax::ast::{AstNode, AstToken};
 use syntax::{ast, SyntaxElement, SyntaxElementChildren, SyntaxKind, SyntaxNode, SyntaxToken};
+use syntax::{
+    ast::{AstNode, AstToken},
+    SmolStr,
+};
 use test_utils::mark;
 // Creates a match error. If we're currently attempting to match some code that we thought we were
@@ -398,11 +401,11 @@ impl<'db, 'sema> Matcher<'db, 'sema> {
        code: &SyntaxNode,
    ) -> Result<(), MatchFailed> {
        // Build a map keyed by field name.
-        let mut fields_by_name = FxHashMap::default();
+        let mut fields_by_name: FxHashMap<SmolStr, SyntaxNode> = FxHashMap::default();
        for child in code.children() {
            if let Some(record) = ast::RecordExprField::cast(child.clone()) {
                if let Some(name) = record.field_name() {
-                    fields_by_name.insert(name.text().clone(), child.clone());
+                    fields_by_name.insert(name.text().into(), child.clone());
                }
            }
        }
@@ -473,9 +476,7 @@ impl<'db, 'sema> Matcher<'db, 'sema> {
                        }
                        SyntaxElement::Node(n) => {
                            if let Some(first_token) = n.first_token() {
-                                if Some(first_token.text().as_str())
+                                if Some(first_token.text()) == next_pattern_token.as_deref() {
-                                    == 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)?;
diff --git a/crates/ssr/src/replacing.rs b/crates/ssr/src/replacing.rs
index 7e7ce37bd..06a94a46c 100644
--- a/crates/ssr/src/replacing.rs
+++ b/crates/ssr/src/replacing.rs
@@ -173,7 +173,7 @@ impl ReplacementRenderer<'_> {
                );
            }
        } else {
-            self.out.push_str(token.text().as_str());
+            self.out.push_str(token.text());
        }
    }
diff --git a/crates/ssr/src/resolving.rs b/crates/ssr/src/resolving.rs
index f5ceb5729..14e5a3b69 100644
--- a/crates/ssr/src/resolving.rs
+++ b/crates/ssr/src/resolving.rs
@@ -228,7 +228,7 @@ impl<'db> ResolutionScope<'db> {
                None,
                |_ty, assoc_item| {
                    let item_name = assoc_item.name(self.scope.db)?;
-                    if item_name.to_string().as_str() == name.text().as_str() {
+                    if item_name.to_string().as_str() == name.text() {
                        Some(hir::PathResolution::AssocItem(assoc_item))
                    } else {
                        None
diff --git a/crates/syntax/Cargo.toml b/crates/syntax/Cargo.toml
index 52394b337..24298fbfa 100644
--- a/crates/syntax/Cargo.toml
+++ b/crates/syntax/Cargo.toml
@@ -12,15 +12,12 @@ doctest = false
 [dependencies]
 itertools = "0.10.0"
-rowan = "0.10.3"
+rowan = "0.12"
-rustc_lexer = { version = "697.0.0", package = "rustc-ap-rustc_lexer" }
+rustc_lexer = { version = "700.0.0", package = "rustc-ap-rustc_lexer" }
 rustc-hash = "1.1.0"
 arrayvec = "0.5.1"
 once_cell = "1.3.1"
 indexmap = "1.4.0"
-# This crate transitively depends on `smol_str` via `rowan`.
-# ideally, `serde` should be enabled by `rust-analyzer`, but we enable it here
-# to reduce number of compilations
 smol_str = { version = "0.1.15", features = ["serde"] }
 serde = { version = "1.0.106", features = ["derive"] }
diff --git a/crates/syntax/src/algo.rs b/crates/syntax/src/algo.rs
index 827ae78f9..2ff92f9f6 100644
--- a/crates/syntax/src/algo.rs
+++ b/crates/syntax/src/algo.rs
@@ -4,6 +4,7 @@ use std::{
    fmt,
    hash::BuildHasherDefault,
    ops::{self, RangeInclusive},
+    ptr,
 };
 use indexmap::IndexMap;
@@ -171,7 +172,7 @@ pub fn diff(from: &SyntaxNode, to: &SyntaxNode) -> TreeDiff {
            && lhs.text_range().len() == rhs.text_range().len()
            && match (&lhs, &rhs) {
                (NodeOrToken::Node(lhs), NodeOrToken::Node(rhs)) => {
-                    lhs.green() == rhs.green() || lhs.text() == rhs.text()
+                    ptr::eq(lhs.green(), rhs.green()) || lhs.text() == rhs.text()
                }
                (NodeOrToken::Token(lhs), NodeOrToken::Token(rhs)) => lhs.text() == rhs.text(),
                _ => false,
@@ -566,7 +567,7 @@ impl<'a> SyntaxRewriter<'a> {
 fn element_to_green(element: SyntaxElement) -> NodeOrToken<rowan::GreenNode, rowan::GreenToken> {
    match element {
-        NodeOrToken::Node(it) => NodeOrToken::Node(it.green().clone()),
+        NodeOrToken::Node(it) => NodeOrToken::Node(it.green().to_owned()),
        NodeOrToken::Token(it) => NodeOrToken::Token(it.green().clone()),
    }
 }
@@ -624,7 +625,7 @@ fn position_of_child(parent: &SyntaxNode, child: SyntaxElement) -> usize {
 fn to_green_element(element: SyntaxElement) -> NodeOrToken<rowan::GreenNode, rowan::GreenToken> {
    match element {
-        NodeOrToken::Node(it) => it.green().clone().into(),
+        NodeOrToken::Node(it) => it.green().to_owned().into(),
        NodeOrToken::Token(it) => it.green().clone().into(),
    }
 }
diff --git a/crates/syntax/src/ast.rs b/crates/syntax/src/ast.rs
index 83de067d9..a25ff655e 100644
--- a/crates/syntax/src/ast.rs
+++ b/crates/syntax/src/ast.rs
@@ -12,7 +12,7 @@ use std::marker::PhantomData;
 use crate::{
    syntax_node::{SyntaxNode, SyntaxNodeChildren, SyntaxToken},
-    SmolStr, SyntaxKind,
+    SyntaxKind,
 };
 pub use self::{
@@ -54,7 +54,7 @@ pub trait AstToken {
    fn syntax(&self) -> &SyntaxToken;
-    fn text(&self) -> &SmolStr {
+    fn text(&self) -> &str {
        self.syntax().text()
    }
 }
diff --git a/crates/syntax/src/ast/make.rs b/crates/syntax/src/ast/make.rs
index 9ffc3ae11..b755c9692 100644
--- a/crates/syntax/src/ast/make.rs
+++ b/crates/syntax/src/ast/make.rs
@@ -478,7 +478,7 @@ fn ast_from_text<N: AstNode>(text: &str) -> N {
 }
 fn unroot(n: SyntaxNode) -> SyntaxNode {
-    SyntaxNode::new_root(n.green().clone())
+    SyntaxNode::new_root(n.green().to_owned())
 }
 pub mod tokens {
@@ -495,7 +495,7 @@ pub mod tokens {
            .syntax()
            .descendants_with_tokens()
            .filter_map(|it| it.into_token())
-            .find(|it| it.kind() == WHITESPACE && it.text().as_str() == " ")
+            .find(|it| it.kind() == WHITESPACE && it.text() == " ")
            .unwrap()
    }
@@ -523,7 +523,7 @@ pub mod tokens {
            .syntax()
            .descendants_with_tokens()
            .filter_map(|it| it.into_token())
-            .find(|it| it.kind() == WHITESPACE && it.text().as_str() == "\n")
+            .find(|it| it.kind() == WHITESPACE && it.text() == "\n")
            .unwrap()
    }
@@ -533,7 +533,7 @@ pub mod tokens {
            .syntax()
            .descendants_with_tokens()
            .filter_map(|it| it.into_token())
-            .find(|it| it.kind() == WHITESPACE && it.text().as_str() == "\n\n")
+            .find(|it| it.kind() == WHITESPACE && it.text() == "\n\n")
            .unwrap()
    }
diff --git a/crates/syntax/src/ast/node_ext.rs b/crates/syntax/src/ast/node_ext.rs
index 738c92a5b..5c8cf900f 100644
--- a/crates/syntax/src/ast/node_ext.rs
+++ b/crates/syntax/src/ast/node_ext.rs
@@ -13,19 +13,19 @@ use crate::{
 };
 impl ast::Lifetime {
-    pub fn text(&self) -> &SmolStr {
+    pub fn text(&self) -> &str {
        text_of_first_token(self.syntax())
    }
 }
 impl ast::Name {
-    pub fn text(&self) -> &SmolStr {
+    pub fn text(&self) -> &str {
        text_of_first_token(self.syntax())
    }
 }
 impl ast::NameRef {
-    pub fn text(&self) -> &SmolStr {
+    pub fn text(&self) -> &str {
        text_of_first_token(self.syntax())
    }
@@ -34,7 +34,7 @@ impl ast::NameRef {
    }
 }
-fn text_of_first_token(node: &SyntaxNode) -> &SmolStr {
+fn text_of_first_token(node: &SyntaxNode) -> &str {
    node.green().children().next().and_then(|it| it.into_token()).unwrap().text()
 }
@@ -121,7 +121,7 @@ impl ast::Attr {
    pub fn simple_name(&self) -> Option<SmolStr> {
        let path = self.path()?;
        match (path.segment(), path.qualifier()) {
-            (Some(segment), None) => Some(segment.syntax().first_token()?.text().clone()),
+            (Some(segment), None) => Some(segment.syntax().first_token()?.text().into()),
            _ => None,
        }
    }
diff --git a/crates/syntax/src/ast/token_ext.rs b/crates/syntax/src/ast/token_ext.rs
index 5e9620a40..5e07ec7d1 100644
--- a/crates/syntax/src/ast/token_ext.rs
+++ b/crates/syntax/src/ast/token_ext.rs
@@ -41,7 +41,7 @@ impl ast::Comment {
        match kind {
            CommentKind { shape, doc: Some(_) } => {
                let prefix = kind.prefix();
-                let text = &self.text().as_str()[prefix.len()..];
+                let text = &self.text()[prefix.len()..];
                let ws = text.chars().next().filter(|c| c.is_whitespace());
                let text = ws.map_or(text, |ws| &text[ws.len_utf8()..]);
                match shape {
@@ -156,13 +156,13 @@ impl ast::String {
    pub fn value(&self) -> Option<Cow<'_, str>> {
        if self.is_raw() {
-            let text = self.text().as_str();
+            let text = self.text();
            let text =
                &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
            return Some(Cow::Borrowed(text));
        }
-        let text = self.text().as_str();
+        let text = self.text();
        let text = &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
        let mut buf = String::new();
@@ -190,7 +190,7 @@ impl ast::String {
    }
    pub fn quote_offsets(&self) -> Option<QuoteOffsets> {
-        let text = self.text().as_str();
+        let text = self.text();
        let offsets = QuoteOffsets::new(text)?;
        let o = self.syntax().text_range().start();
        let offsets = QuoteOffsets {
@@ -560,7 +560,7 @@ impl HasFormatSpecifier for ast::String {
    fn char_ranges(
        &self,
    ) -> Option<Vec<(TextRange, Result<char, rustc_lexer::unescape::EscapeError>)>> {
-        let text = self.text().as_str();
+        let text = self.text();
        let text = &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
        let offset = self.text_range_between_quotes()?.start() - self.syntax().text_range().start();
@@ -590,7 +590,7 @@ impl ast::IntNumber {
    pub fn value(&self) -> Option<u128> {
        let token = self.syntax();
-        let mut text = token.text().as_str();
+        let mut text = token.text();
        if let Some(suffix) = self.suffix() {
            text = &text[..text.len() - suffix.len()]
        }
diff --git a/crates/syntax/src/lib.rs b/crates/syntax/src/lib.rs
index ea7482bb1..11294c5b2 100644
--- a/crates/syntax/src/lib.rs
+++ b/crates/syntax/src/lib.rs
@@ -56,9 +56,9 @@ pub use crate::{
 };
 pub use parser::{SyntaxKind, T};
 pub use rowan::{
-    Direction, GreenNode, NodeOrToken, SmolStr, SyntaxText, TextRange, TextSize, TokenAtOffset,
+    Direction, GreenNode, NodeOrToken, SyntaxText, TextRange, TextSize, TokenAtOffset, WalkEvent,
-    WalkEvent,
 };
+pub use smol_str::SmolStr;
 /// `Parse` is the result of the parsing: a syntax tree and a collection of
 /// errors.
diff --git a/crates/syntax/src/parsing/reparsing.rs b/crates/syntax/src/parsing/reparsing.rs
index 76f01084c..3d637bf91 100644
--- a/crates/syntax/src/parsing/reparsing.rs
+++ b/crates/syntax/src/parsing/reparsing.rs
@@ -73,8 +73,7 @@ fn reparse_token<'node>(
                new_text.pop();
            }
-            let new_token =
+            let new_token = GreenToken::new(rowan::SyntaxKind(prev_token_kind.into()), &new_text);
-                GreenToken::new(rowan::SyntaxKind(prev_token_kind.into()), new_text.into());
            Some((
                prev_token.replace_with(new_token),
                new_err.into_iter().collect(),
diff --git a/crates/syntax/src/parsing/text_tree_sink.rs b/crates/syntax/src/parsing/text_tree_sink.rs
index ce27c3dd9..d5ddc076f 100644
--- a/crates/syntax/src/parsing/text_tree_sink.rs
+++ b/crates/syntax/src/parsing/text_tree_sink.rs
@@ -8,7 +8,7 @@ use crate::{
    ast,
    parsing::Token,
    syntax_node::GreenNode,
-    SmolStr, SyntaxError,
+    SyntaxError,
    SyntaxKind::{self, *},
    SyntaxTreeBuilder, TextRange, TextSize,
 };
@@ -135,7 +135,7 @@ impl<'a> TextTreeSink<'a> {
    fn do_token(&mut self, kind: SyntaxKind, len: TextSize, n_tokens: usize) {
        let range = TextRange::at(self.text_pos, len);
-        let text: SmolStr = self.text[range].into();
+        let text = &self.text[range];
        self.text_pos += len;
        self.token_pos += n_tokens;
        self.inner.token(kind, text);
diff --git a/crates/syntax/src/syntax_node.rs b/crates/syntax/src/syntax_node.rs
index cc30138fa..8f643b228 100644
--- a/crates/syntax/src/syntax_node.rs
+++ b/crates/syntax/src/syntax_node.rs
@@ -8,7 +8,7 @@
 use rowan::{GreenNodeBuilder, Language};
-use crate::{Parse, SmolStr, SyntaxError, SyntaxKind, TextSize};
+use crate::{Parse, SyntaxError, SyntaxKind, TextSize};
 pub(crate) use rowan::{GreenNode, GreenToken, NodeOrToken};
@@ -53,7 +53,7 @@ impl SyntaxTreeBuilder {
        Parse::new(green, errors)
    }
-    pub fn token(&mut self, kind: SyntaxKind, text: SmolStr) {
+    pub fn token(&mut self, kind: SyntaxKind, text: &str) {
        let kind = RustLanguage::kind_to_raw(kind);
        self.inner.token(kind, text)
    }
diff --git a/crates/syntax/src/validation.rs b/crates/syntax/src/validation.rs
index 7901580ee..7694e8834 100644
--- a/crates/syntax/src/validation.rs
+++ b/crates/syntax/src/validation.rs
@@ -116,7 +116,7 @@ fn validate_literal(literal: ast::Literal, acc: &mut Vec<SyntaxError>) {
    }
    let token = literal.token();
-    let text = token.text().as_str();
+    let text = token.text();
    // FIXME: lift this lambda refactor to `fn` (https://github.com/rust-analyzer/rust-analyzer/pull/2834#discussion_r366199205)
    let mut push_err = |prefix_len, (off, err): (usize, unescape::EscapeError)| {
diff --git a/docs/dev/README.md b/docs/dev/README.md
index dd2bfc493..24197b332 100644
--- a/docs/dev/README.md
+++ b/docs/dev/README.md
@@ -251,6 +251,9 @@ RA_PROFILE=*@3>10        // dump everything, up to depth 3, if it takes more tha
 In particular, I have `export RA_PROFILE='*>10'` in my shell profile.
+We also have a "counting" profiler which counts number of instances of popular structs.
+It is enabled by `RA_COUNT=1`.
 To measure time for from-scratch analysis, use something like this:
 ```
diff --git a/docs/dev/style.md b/docs/dev/style.md
index 21330948b..428cee3ad 100644
--- a/docs/dev/style.md
+++ b/docs/dev/style.md
@@ -6,6 +6,9 @@ Our approach to "clean code" is two-fold:
 It is explicitly OK for a reviewer to flag only some nits in the PR, and then send a follow-up cleanup PR for things which are easier to explain by example, cc-ing the original author.
 Sending small cleanup PRs (like renaming a single local variable) is encouraged.
+When reviewing pull requests prefer extending this document to leaving
+non-reusable comments on the pull request itself.
 # General
 ## Scale of Changes
@@ -139,6 +142,17 @@ There are many benefits to this:
 Formatting ensures that you can use your editor's "number of selected characters" feature to correlate offsets with test's source code.
+## Marked Tests
+Use
+[`mark::hit! / mark::check!`](https://github.com/rust-analyzer/rust-analyzer/blob/71fe719dd5247ed8615641d9303d7ca1aa201c2f/crates/test_utils/src/mark.rs)
+when testing specific conditions.
+Do not place several marks into a single test or condition.
+Do not reuse marks between several tests.
+**Rationale:** marks provide an easy way to find the canonical test for each bit of code.
+This makes it much easier to understand.
 ## Function Preconditions
 Express function preconditions in types and force the caller to provide them (rather than checking in callee):
@@ -280,6 +294,9 @@ Prefer `Default` even it has to be implemented manually.
 **Rationale:** less typing in the common case, uniformity.
+Use `Vec::new` rather than `vec![]`. **Rationale:** uniformity, strength
+reduction.
 ## Functions Over Objects
 Avoid creating "doer" objects.
@@ -372,6 +389,14 @@ This allows for exceptionally good performance, but leads to increased compile t
 Runtime performance obeys 80%/20% rule -- only a small fraction of code is hot.
 Compile time **does not** obey this rule -- all code has to be compiled.
+## Appropriate String Types
+When interfacing with OS APIs, use `OsString`, even if the original source of data is utf-8 encoded.
+**Rationale:** cleanly delineates the boundary when the data goes into the OS-land.
+Use `AbsPathBuf` and `AbsPath` over `std::Path`.
+**Rationale:** rust-analyzer is a long-lived process which handles several projects at the same time.
+It is important not to leak cwd by accident.
 # Premature Pessimization
@@ -418,12 +443,44 @@ fn frobnicate(s: &str) {
 **Rationale:** reveals the costs.
 It is also more efficient when the caller already owns the allocation.
-## Collection types
+## Collection Types
 Prefer `rustc_hash::FxHashMap` and `rustc_hash::FxHashSet` instead of the ones in `std::collections`.
 **Rationale:** they use a hasher that's significantly faster and using them consistently will reduce code size by some small amount.
+## Avoid Intermediate Collections
+When writing a recursive function to compute a sets of things, use an accumulator parameter instead of returning a fresh collection.
+Accumulator goes first in the list of arguments.
+```rust
+// GOOD
+pub fn reachable_nodes(node: Node) -> FxHashSet<Node> {
+    let mut res = FxHashSet::default();
+    go(&mut res, node);
+    res
+}
+fn go(acc: &mut FxHashSet<Node>, node: Node) {
+    acc.insert(node);
+    for n in node.neighbors() {
+        go(acc, n);
+    }
+}
+// BAD
+pub fn reachable_nodes(node: Node) -> FxHashSet<Node> {
+    let mut res = FxHashSet::default();
+    res.insert(node);
+    for n in node.neighbors() {
+        res.extend(reachable_nodes(n));
+    }
+    res
+}
+```
+**Rational:** re-use allocations, accumulator style is more concise for complex cases.
 # Style
 ## Order of Imports
diff --git a/xtask/Cargo.toml b/xtask/Cargo.toml
index 4abc7b053..4e6b439fd 100644
--- a/xtask/Cargo.toml
+++ b/xtask/Cargo.toml
@@ -12,7 +12,7 @@ doctest = false
 [dependencies]
 anyhow = "1.0.26"
 flate2 = "1.0"
-pico-args = "0.3.1"
+pico-args = "0.4.0"
 proc-macro2 = "1.0.8"
 quote = "1.0.2"
 ungrammar = "1.9"
diff --git a/xtask/src/codegen/gen_assists_docs.rs b/xtask/src/codegen/gen_assists_docs.rs
index 6e18a50a6..51f58180c 100644
--- a/xtask/src/codegen/gen_assists_docs.rs
+++ b/xtask/src/codegen/gen_assists_docs.rs
@@ -4,7 +4,7 @@ use std::{fmt, path::Path};
 use crate::{
    codegen::{self, extract_comment_blocks_with_empty_lines, reformat, Location, Mode, PREAMBLE},
-    project_root, rust_files, Result,
+    project_root, rust_files_in, Result,
 };
 pub fn generate_assists_tests(mode: Mode) -> Result<()> {
@@ -32,7 +32,7 @@ struct Assist {
 impl Assist {
    fn collect() -> Result<Vec<Assist>> {
        let mut res = Vec::new();
-        for path in rust_files(&project_root().join("crates/assists/src/handlers")) {
+        for path in rust_files_in(&project_root().join("crates/assists/src/handlers")) {
            collect_file(&mut res, path.as_path())?;
        }
        res.sort_by(|lhs, rhs| lhs.id.cmp(&rhs.id));
diff --git a/xtask/src/codegen/gen_diagnostic_docs.rs b/xtask/src/codegen/gen_diagnostic_docs.rs
index 00aaea5b7..7c14d4a07 100644
--- a/xtask/src/codegen/gen_diagnostic_docs.rs
+++ b/xtask/src/codegen/gen_diagnostic_docs.rs
@@ -27,7 +27,7 @@ struct Diagnostic {
 impl Diagnostic {
    fn collect() -> Result<Vec<Diagnostic>> {
        let mut res = Vec::new();
-        for path in rust_files(&project_root()) {
+        for path in rust_files() {
            collect_file(&mut res, path)?;
        }
        res.sort_by(|lhs, rhs| lhs.id.cmp(&rhs.id));
diff --git a/xtask/src/codegen/gen_feature_docs.rs b/xtask/src/codegen/gen_feature_docs.rs
index 065dd33f1..61081063b 100644
--- a/xtask/src/codegen/gen_feature_docs.rs
+++ b/xtask/src/codegen/gen_feature_docs.rs
@@ -26,7 +26,7 @@ struct Feature {
 impl Feature {
    fn collect() -> Result<Vec<Feature>> {
        let mut res = Vec::new();
-        for path in rust_files(&project_root()) {
+        for path in rust_files() {
            collect_file(&mut res, path)?;
        }
        res.sort_by(|lhs, rhs| lhs.id.cmp(&rhs.id));
diff --git a/xtask/src/lib.rs b/xtask/src/lib.rs
index babec2dbd..16b06b853 100644
--- a/xtask/src/lib.rs
+++ b/xtask/src/lib.rs
@@ -34,7 +34,11 @@ pub fn project_root() -> PathBuf {
    .to_path_buf()
 }
-pub fn rust_files(path: &Path) -> impl Iterator<Item = PathBuf> {
+pub fn rust_files() -> impl Iterator<Item = PathBuf> {
+    rust_files_in(&project_root().join("crates"))
+}
+pub fn rust_files_in(path: &Path) -> impl Iterator<Item = PathBuf> {
    let iter = WalkDir::new(path);
    return iter
        .into_iter()
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
index c3e5c7326..5a99f4a76 100644
--- a/xtask/src/main.rs
+++ b/xtask/src/main.rs
@@ -10,6 +10,7 @@
 use std::env;
+use anyhow::bail;
 use codegen::CodegenCmd;
 use pico_args::Arguments;
 use xshell::{cmd, cp, pushd};
@@ -76,7 +77,7 @@ FLAGS:
            let client_opt = args.opt_value_from_str("--client")?;
-            args.finish()?;
+            finish_args(args)?;
            InstallCmd {
                client: if server { None } else { Some(client_opt.unwrap_or_default()) },
@@ -86,53 +87,53 @@ FLAGS:
        }
        "codegen" => {
            let features = args.contains("--features");
-            args.finish()?;
+            finish_args(args)?;
            CodegenCmd { features }.run()
        }
        "format" => {
-            args.finish()?;
+            finish_args(args)?;
            run_rustfmt(Mode::Overwrite)
        }
        "install-pre-commit-hook" => {
-            args.finish()?;
+            finish_args(args)?;
            pre_commit::install_hook()
        }
        "lint" => {
-            args.finish()?;
+            finish_args(args)?;
            run_clippy()
        }
        "fuzz-tests" => {
-            args.finish()?;
+            finish_args(args)?;
            run_fuzzer()
        }
        "pre-cache" => {
-            args.finish()?;
+            finish_args(args)?;
            PreCacheCmd.run()
        }
        "release" => {
            let dry_run = args.contains("--dry-run");
-            args.finish()?;
+            finish_args(args)?;
            ReleaseCmd { dry_run }.run()
        }
        "promote" => {
            let dry_run = args.contains("--dry-run");
-            args.finish()?;
+            finish_args(args)?;
            PromoteCmd { dry_run }.run()
        }
        "dist" => {
            let nightly = args.contains("--nightly");
            let client_version: Option<String> = args.opt_value_from_str("--client")?;
-            args.finish()?;
+            finish_args(args)?;
            DistCmd { nightly, client_version }.run()
        }
        "metrics" => {
            let dry_run = args.contains("--dry-run");
-            args.finish()?;
+            finish_args(args)?;
            MetricsCmd { dry_run }.run()
        }
        "bb" => {
-            let suffix: String = args.free_from_str()?.unwrap();
+            let suffix: String = args.free_from_str()?;
-            args.finish()?;
+            finish_args(args)?;
            cmd!("cargo build --release").run()?;
            cp("./target/release/rust-analyzer", format!("./target/rust-analyzer-{}", suffix))?;
            Ok(())
@@ -161,3 +162,10 @@ SUBCOMMANDS:
        }
    }
 }
+fn finish_args(args: Arguments) -> Result<()> {
+    if !args.finish().is_empty() {
+        bail!("Unused arguments.");
+    }
+    Ok(())
+}
diff --git a/xtask/tests/tidy.rs b/xtask/tests/tidy.rs
index 6abad189a..9a6933b09 100644
--- a/xtask/tests/tidy.rs
+++ b/xtask/tests/tidy.rs
@@ -82,7 +82,7 @@ Please adjust docs/dev/lsp-extensions.md.
 #[test]
 fn rust_files_are_tidy() {
    let mut tidy_docs = TidyDocs::default();
-    for path in rust_files(&project_root().join("crates")) {
+    for path in rust_files() {
        let text = read_file(&path).unwrap();
        check_todo(&path, &text);
        check_dbg(&path, &text);