Merge commit '37f84c101bca43b11027f30ab0c2852f9325bc3d' into sync-from-ra

.editorconfig

@@ -7,13 +7,10 @@ trim_trailing_whitespace = true
 end_of_line = lf
 insert_final_newline = true
 indent_style = space
-
-[*.{rs,toml}]
 indent_size = 4
 
-[*.ts]
+[*.md]
-indent_size = 4
+indent_size = 2
-[*.js]
+
-indent_size = 4
+[*.{yml, yaml}]
-[*.json]
+indent_size = 2
-indent_size = 4

.github/workflows/autopublish.yaml

@@ -49,8 +49,8 @@ jobs:
           cargo workspaces rename --from project-model project_model
           cargo workspaces rename --from test-utils test_utils
           cargo workspaces rename --from text-edit text_edit
-          cargo workspaces rename ra_ap_%n
           # Remove library crates from the workspaces so we don't auto-publish them as well
           sed -i 's/ "lib\/\*",//' ./Cargo.toml
+          cargo workspaces rename ra_ap_%n
           find crates/rust-analyzer -type f -name '*.rs' -exec sed -i 's/rust_analyzer/ra_ap_rust_analyzer/g' {} +
           cargo workspaces publish --yes --force '*' --exact --no-git-commit --allow-dirty --skip-published custom 0.0.$(($RUN_NUMBER + 133))

.github/workflows/metrics.yaml

@@ -1,8 +1,8 @@
 name: metrics
 on:
   push:
-   branches:
+    branches:
-   - master
+      - master
 
 env:
   CARGO_INCREMENTAL: 0
@@ -11,20 +11,135 @@ env:
   RUSTUP_MAX_RETRIES: 10
 
 jobs:
-  metrics:
+  setup_cargo:
     if: github.repository == 'rust-lang/rust-analyzer'
     runs-on: ubuntu-latest
+    steps:
+      - name: Install Rust toolchain
+        run: |
+          rustup update --no-self-update stable
+          rustup component add rustfmt rust-src
+          rustup default stable
+      - name: Cache cargo
+        uses: actions/cache@v3
+        with:
+          path: |
+            ~/.cargo/bin/
+            ~/.cargo/registry/index/
+            ~/.cargo/registry/cache/
+            ~/.cargo/git/db/
+          key: ${{ runner.os }}-cargo-${{ github.sha }}
+
+  build_metrics:
+    runs-on: ubuntu-latest
+    needs: setup_cargo
 
     steps:
-    - name: Checkout repository
+      - name: Checkout repository
-      uses: actions/checkout@v3
+        uses: actions/checkout@v3
 
-    - name: Install Rust toolchain
+      - name: Restore cargo cache
-      run: |
+        uses: actions/cache@v3
-        rustup update --no-self-update stable
+        with:
-        rustup component add rustfmt rust-src
+          path: |
+            ~/.cargo/bin/
+            ~/.cargo/registry/index/
+            ~/.cargo/registry/cache/
+            ~/.cargo/git/db/
+          key: ${{ runner.os }}-cargo-${{ github.sha }}
 
-    - name: Collect metrics
+      - name: Collect build metrics
-      run: cargo xtask metrics
+        run: cargo xtask metrics build
-      env:
+
-        METRICS_TOKEN: ${{ secrets.METRICS_TOKEN }}
+      - name: Cache target
+        uses: actions/cache@v3
+        with:
+          path: target/
+          key: ${{ runner.os }}-target-${{ github.sha }}
+
+      - name: Upload build metrics
+        uses: actions/upload-artifact@v3
+        with:
+          name: build-${{ github.sha }}
+          path: target/build.json
+          if-no-files-found: error
+
+  other_metrics:
+    strategy:
+      matrix:
+        names: [self, ripgrep, webrender, diesel]
+    runs-on: ubuntu-latest
+    needs: [setup_cargo, build_metrics]
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Restore cargo cache
+        uses: actions/cache@v3
+        with:
+          path: |
+            ~/.cargo/bin/
+            ~/.cargo/registry/index/
+            ~/.cargo/registry/cache/
+            ~/.cargo/git/db/
+          key: ${{ runner.os }}-cargo-${{ github.sha }}
+
+      - name: Restore target cache
+        uses: actions/cache@v3
+        with:
+          path: target/
+          key: ${{ runner.os }}-target-${{ github.sha }}
+
+      - name: Collect metrics
+        run: cargo xtask metrics ${{ matrix.names }}
+
+      - name: Upload metrics
+        uses: actions/upload-artifact@v3
+        with:
+          name: ${{ matrix.names }}-${{ github.sha }}
+          path: target/${{ matrix.names }}.json
+          if-no-files-found: error
+
+  generate_final_metrics:
+    runs-on: ubuntu-latest
+    needs: [build_metrics, other_metrics]
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Download build metrics
+        uses: actions/download-artifact@v3
+        with:
+          name: build-${{ github.sha }}
+
+      - name: Download self metrics
+        uses: actions/download-artifact@v3
+        with:
+          name: self-${{ github.sha }}
+
+      - name: Download ripgrep metrics
+        uses: actions/download-artifact@v3
+        with:
+          name: ripgrep-${{ github.sha }}
+
+      - name: Download webrender metrics
+        uses: actions/download-artifact@v3
+        with:
+          name: webrender-${{ github.sha }}
+
+      - name: Download diesel metrics
+        uses: actions/download-artifact@v3
+        with:
+          name: diesel-${{ github.sha }}
+
+      - name: Combine json
+        run: |
+          git clone --depth 1 https://$METRICS_TOKEN@github.com/rust-analyzer/metrics.git
+          jq -s ".[0] * .[1] * .[2] * .[3] * .[4]" build.json self.json ripgrep.json webrender.json diesel.json -c >> metrics/metrics.json
+          cd metrics
+          git add .
+          git -c user.name=Bot -c user.email=dummy@example.com commit --message 📈
+          git push origin master
+    env:
+      METRICS_TOKEN: ${{ secrets.METRICS_TOKEN }}

Cargo.toml

@@ -4,7 +4,7 @@ exclude = ["crates/proc-macro-test/imp"]
 resolver = "2"
 
 [workspace.package]
-rust-version = "1.66"
+rust-version = "1.70"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 authors = ["rust-analyzer team"]
@@ -35,6 +35,10 @@ debug = 0
 # chalk-ir = { path = "../chalk/chalk-ir" }
 # chalk-recursive = { path = "../chalk/chalk-recursive" }
 # chalk-derive = { path = "../chalk/chalk-derive" }
+# line-index = { path = "lib/line-index" }
+# la-arena = { path = "lib/la-arena" }
+# lsp-server = { path = "lib/lsp-server" }
+
 
 # ungrammar = { path = "../ungrammar" }
 
@@ -57,13 +61,13 @@ ide-diagnostics = { path = "./crates/ide-diagnostics", version = "0.0.0" }
 ide-ssr = { path = "./crates/ide-ssr", version = "0.0.0" }
 intern = { path = "./crates/intern", version = "0.0.0" }
 limit = { path = "./crates/limit", version = "0.0.0" }
+load-cargo = { path = "./crates/load-cargo", version = "0.0.0" }
 mbe = { path = "./crates/mbe", version = "0.0.0" }
 parser = { path = "./crates/parser", version = "0.0.0" }
 paths = { path = "./crates/paths", version = "0.0.0" }
 proc-macro-api = { path = "./crates/proc-macro-api", version = "0.0.0" }
 proc-macro-srv = { path = "./crates/proc-macro-srv", version = "0.0.0" }
 proc-macro-srv-cli = { path = "./crates/proc-macro-srv-cli", version = "0.0.0" }
-proc-macro-test = { path = "./crates/proc-macro-test", version = "0.0.0" }
 profile = { path = "./crates/profile", version = "0.0.0" }
 project-model = { path = "./crates/project-model", version = "0.0.0" }
 sourcegen = { path = "./crates/sourcegen", version = "0.0.0" }
@@ -75,7 +79,14 @@ toolchain = { path = "./crates/toolchain", version = "0.0.0" }
 tt = { path = "./crates/tt", version = "0.0.0" }
 vfs-notify = { path = "./crates/vfs-notify", version = "0.0.0" }
 vfs = { path = "./crates/vfs", version = "0.0.0" }
-line-index = { version = "0.1.0-pre.1", path = "./lib/line-index" }
+
+# local crates that aren't published to crates.io. These should not have versions.
+proc-macro-test = { path = "./crates/proc-macro-test" }
+
+# In-tree crates that are published separately and follow semver. See lib/README.md
+line-index = { version = "0.1.0-pre.1" }
+la-arena = { version = "0.3.1" }
+lsp-server = { version = "0.7.1" }
 
 # non-local crates
 smallvec = { version = "1.10.0", features = [
@@ -86,9 +97,10 @@ smallvec = { version = "1.10.0", features = [
 smol_str = "0.2.0"
 nohash-hasher = "0.2.0"
 text-size = "1.1.0"
-# the following crates are pinned to prevent us from pulling in syn 2 until all our dependencies have moved
+serde = { version = "1.0.156", features = ["derive"] }
-serde = { version = "=1.0.156", features = ["derive"] }
+serde_json = "1.0.96"
-serde_json = "1.0.94"
 triomphe = { version = "0.1.8", default-features = false, features = ["std"] }
+# can't upgrade due to dashmap depending on 0.12.3 currently
+hashbrown = { version = "0.12.3", features = ["inline-more"], default-features = false }
 
 rustc_lexer = { version = "0.1.0", package = "ra-ap-rustc_lexer" }

crates/base-db/Cargo.toml

@@ -17,7 +17,7 @@ rustc-hash = "1.1.0"
 
 triomphe.workspace = true
 
-la-arena = { version = "0.3.0", path = "../../lib/la-arena" }
+la-arena.workspace = true
 
 # local deps
 cfg.workspace = true

crates/base-db/src/fixture.rs

@@ -26,7 +26,7 @@ pub trait WithFixture: Default + SourceDatabaseExt + 'static {
         let fixture = ChangeFixture::parse(ra_fixture);
         let mut db = Self::default();
         fixture.change.apply(&mut db);
-        assert_eq!(fixture.files.len(), 1);
+        assert_eq!(fixture.files.len(), 1, "Multiple file found in the fixture");
         (db, fixture.files[0])
     }
 
@@ -102,6 +102,8 @@ pub struct ChangeFixture {
     pub change: Change,
 }
 
+const SOURCE_ROOT_PREFIX: &str = "/";
+
 impl ChangeFixture {
     pub fn parse(ra_fixture: &str) -> ChangeFixture {
         Self::parse_with_proc_macros(ra_fixture, Vec::new())
@@ -131,7 +133,6 @@ impl ChangeFixture {
 
         let mut file_set = FileSet::default();
         let mut current_source_root_kind = SourceRootKind::Local;
-        let source_root_prefix = "/".to_string();
         let mut file_id = FileId(0);
         let mut roots = Vec::new();
 
@@ -151,19 +152,23 @@ impl ChangeFixture {
                 entry.text.clone()
             };
 
-            let meta = FileMeta::from(entry);
+            let meta = FileMeta::from_fixture(entry, current_source_root_kind);
-            assert!(meta.path.starts_with(&source_root_prefix));
+            assert!(meta.path.starts_with(SOURCE_ROOT_PREFIX));
             if !meta.deps.is_empty() {
                 assert!(meta.krate.is_some(), "can't specify deps without naming the crate")
             }
 
-            if let Some(kind) = &meta.introduce_new_source_root {
+            if let Some(kind) = meta.introduce_new_source_root {
-                let root = match current_source_root_kind {
+                assert!(
+                    meta.krate.is_some(),
+                    "new_source_root meta doesn't make sense without crate meta"
+                );
+                let prev_kind = mem::replace(&mut current_source_root_kind, kind);
+                let prev_root = match prev_kind {
                     SourceRootKind::Local => SourceRoot::new_local(mem::take(&mut file_set)),
                     SourceRootKind::Library => SourceRoot::new_library(mem::take(&mut file_set)),
                 };
-                roots.push(root);
+                roots.push(prev_root);
-                current_source_root_kind = *kind;
             }
 
             if let Some((krate, origin, version)) = meta.krate {
@@ -185,7 +190,7 @@ impl ChangeFixture {
                     Some(toolchain),
                 );
                 let prev = crates.insert(crate_name.clone(), crate_id);
-                assert!(prev.is_none());
+                assert!(prev.is_none(), "multiple crates with same name: {}", crate_name);
                 for dep in meta.deps {
                     let prelude = meta.extern_prelude.contains(&dep);
                     let dep = CrateName::normalize_dashes(&dep);
@@ -219,7 +224,7 @@ impl ChangeFixture {
                 false,
                 CrateOrigin::Local { repo: None, name: None },
                 default_target_data_layout
-                    .map(|x| x.into())
+                    .map(|it| it.into())
                     .ok_or_else(|| "target_data_layout unset".into()),
                 Some(toolchain),
             );
@@ -442,51 +447,74 @@ struct FileMeta {
     target_data_layout: Option<String>,
 }
 
-fn parse_crate(crate_str: String) -> (String, CrateOrigin, Option<String>) {
+impl FileMeta {
-    if let Some((a, b)) = crate_str.split_once('@') {
+    fn from_fixture(f: Fixture, current_source_root_kind: SourceRootKind) -> Self {
-        let (version, origin) = match b.split_once(':') {
-            Some(("CratesIo", data)) => match data.split_once(',') {
-                Some((version, url)) => {
-                    (version, CrateOrigin::Local { repo: Some(url.to_owned()), name: None })
-                }
-                _ => panic!("Bad crates.io parameter: {data}"),
-            },
-            _ => panic!("Bad string for crate origin: {b}"),
-        };
-        (a.to_owned(), origin, Some(version.to_string()))
-    } else {
-        let crate_origin = match LangCrateOrigin::from(&*crate_str) {
-            LangCrateOrigin::Other => CrateOrigin::Local { repo: None, name: None },
-            origin => CrateOrigin::Lang(origin),
-        };
-        (crate_str, crate_origin, None)
-    }
-}
-
-impl From<Fixture> for FileMeta {
-    fn from(f: Fixture) -> FileMeta {
         let mut cfg = CfgOptions::default();
-        f.cfg_atoms.iter().for_each(|it| cfg.insert_atom(it.into()));
+        for (k, v) in f.cfgs {
-        f.cfg_key_values.iter().for_each(|(k, v)| cfg.insert_key_value(k.into(), v.into()));
+            if let Some(v) = v {
+                cfg.insert_key_value(k.into(), v.into());
+            } else {
+                cfg.insert_atom(k.into());
+            }
+        }
+
+        let introduce_new_source_root = f.introduce_new_source_root.map(|kind| match &*kind {
+            "local" => SourceRootKind::Local,
+            "library" => SourceRootKind::Library,
+            invalid => panic!("invalid source root kind '{invalid}'"),
+        });
+        let current_source_root_kind =
+            introduce_new_source_root.unwrap_or(current_source_root_kind);
+
         let deps = f.deps;
-        FileMeta {
+        Self {
             path: f.path,
-            krate: f.krate.map(parse_crate),
+            krate: f.krate.map(|it| parse_crate(it, current_source_root_kind, f.library)),
             extern_prelude: f.extern_prelude.unwrap_or_else(|| deps.clone()),
             deps,
             cfg,
-            edition: f.edition.as_ref().map_or(Edition::CURRENT, |v| Edition::from_str(v).unwrap()),
+            edition: f.edition.map_or(Edition::CURRENT, |v| Edition::from_str(&v).unwrap()),
             env: f.env.into_iter().collect(),
-            introduce_new_source_root: f.introduce_new_source_root.map(|kind| match &*kind {
+            introduce_new_source_root,
-                "local" => SourceRootKind::Local,
-                "library" => SourceRootKind::Library,
-                invalid => panic!("invalid source root kind '{invalid}'"),
-            }),
             target_data_layout: f.target_data_layout,
         }
     }
 }
 
+fn parse_crate(
+    crate_str: String,
+    current_source_root_kind: SourceRootKind,
+    explicit_non_workspace_member: bool,
+) -> (String, CrateOrigin, Option<String>) {
+    // syntax:
+    //   "my_awesome_crate"
+    //   "my_awesome_crate@0.0.1,http://example.com"
+    let (name, repo, version) = if let Some((name, remain)) = crate_str.split_once('@') {
+        let (version, repo) =
+            remain.split_once(',').expect("crate meta: found '@' without version and url");
+        (name.to_owned(), Some(repo.to_owned()), Some(version.to_owned()))
+    } else {
+        (crate_str, None, None)
+    };
+
+    let non_workspace_member = explicit_non_workspace_member
+        || matches!(current_source_root_kind, SourceRootKind::Library);
+
+    let origin = match LangCrateOrigin::from(&*name) {
+        LangCrateOrigin::Other => {
+            let name = name.clone();
+            if non_workspace_member {
+                CrateOrigin::Library { repo, name }
+            } else {
+                CrateOrigin::Local { repo, name: Some(name) }
+            }
+        }
+        origin => CrateOrigin::Lang(origin),
+    };
+
+    (name, origin, version)
+}
+
 // Identity mapping
 #[derive(Debug)]
 struct IdentityProcMacroExpander;

crates/base-db/src/input.rs

@@ -138,12 +138,12 @@ impl ops::Deref for CrateName {
     }
 }
 
-/// Origin of the crates. It is used in emitting monikers.
+/// Origin of the crates.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum CrateOrigin {
-    /// Crates that are from the rustc workspace
+    /// Crates that are from the rustc workspace.
     Rustc { name: String },
-    /// Crates that are workspace members,
+    /// Crates that are workspace members.
     Local { repo: Option<String>, name: Option<String> },
     /// Crates that are non member libraries.
     Library { repo: Option<String>, name: String },

crates/cfg/Cargo.toml

@@ -18,13 +18,13 @@ rustc-hash = "1.1.0"
 tt.workspace = true
 
 [dev-dependencies]
-expect-test = "1.4.0"
+expect-test = "1.4.1"
 oorandom = "11.1.3"
 # We depend on both individually instead of using `features = ["derive"]` to microoptimize the
 # build graph: if the feature was enabled, syn would be built early on in the graph if `smolstr`
 # supports `arbitrary`. This way, we avoid feature unification.
-arbitrary = "1.2.2"
+arbitrary = "1.3.0"
-derive_arbitrary = "1.2.2"
+derive_arbitrary = "1.3.1"
 
 # local deps
 mbe.workspace = true

crates/cfg/src/lib.rs

@@ -69,7 +69,7 @@ impl CfgOptions {
     }
 
     pub fn get_cfg_keys(&self) -> impl Iterator<Item = &SmolStr> {
-        self.enabled.iter().map(|x| match x {
+        self.enabled.iter().map(|it| match it {
             CfgAtom::Flag(key) => key,
             CfgAtom::KeyValue { key, .. } => key,
         })
@@ -79,7 +79,7 @@ impl CfgOptions {
         &'a self,
         cfg_key: &'a str,
     ) -> impl Iterator<Item = &'a SmolStr> + 'a {
-        self.enabled.iter().filter_map(move |x| match x {
+        self.enabled.iter().filter_map(move |it| match it {
             CfgAtom::KeyValue { key, value } if cfg_key == key => Some(value),
             _ => None,
         })

crates/flycheck/Cargo.toml

@@ -12,9 +12,9 @@ rust-version.workspace = true
 doctest = false
 
 [dependencies]
-crossbeam-channel = "0.5.5"
+crossbeam-channel = "0.5.8"
 tracing = "0.1.37"
-cargo_metadata = "0.15.0"
+cargo_metadata = "0.15.4"
 rustc-hash = "1.1.0"
 serde_json.workspace = true
 serde.workspace = true

crates/hir-def/Cargo.toml

@@ -21,14 +21,14 @@ dashmap = { version = "=5.4.0", features = ["raw-api"] }
 drop_bomb = "0.1.5"
 either = "1.7.0"
 fst = { version = "0.4.7", default-features = false }
-hashbrown = { version = "0.12.1", default-features = false }
+indexmap = "2.0.0"
-indexmap = "1.9.1"
 itertools = "0.10.5"
-la-arena = { version = "0.3.0", path = "../../lib/la-arena" }
+la-arena.workspace = true
 once_cell = "1.17.0"
 rustc-hash = "1.1.0"
-smallvec.workspace = true
 tracing = "0.1.35"
+smallvec.workspace = true
+hashbrown.workspace = true
 triomphe.workspace = true
 
 rustc_abi = { version = "0.0.20221221", package = "hkalbasi-rustc-ap-rustc_abi", default-features = false }

crates/hir-def/src/attr.rs

@@ -137,13 +137,16 @@ impl Attrs {
 
                 let cfg_options = &crate_graph[krate].cfg_options;
 
-                let Some(variant) = enum_.variants.clone().filter(|variant| {
+                let Some(variant) = enum_
-                    let attrs = item_tree.attrs(db, krate, (*variant).into());
+                    .variants
-                    attrs.is_cfg_enabled(cfg_options)
+                    .clone()
-                })
+                    .filter(|variant| {
-                .zip(0u32..)
+                        let attrs = item_tree.attrs(db, krate, (*variant).into());
-                .find(|(_variant, idx)| it.local_id == Idx::from_raw(RawIdx::from(*idx)))
+                        attrs.is_cfg_enabled(cfg_options)
-                .map(|(variant, _idx)| variant)
+                    })
+                    .zip(0u32..)
+                    .find(|(_variant, idx)| it.local_id == Idx::from_raw(RawIdx::from(*idx)))
+                    .map(|(variant, _idx)| variant)
                 else {
                     return Arc::new(res);
                 };
@@ -272,6 +275,25 @@ impl Attrs {
         self.by_key("proc_macro_derive").exists()
     }
 
+    pub fn is_test(&self) -> bool {
+        self.iter().any(|it| {
+            it.path()
+                .segments()
+                .iter()
+                .rev()
+                .zip(["core", "prelude", "v1", "test"].iter().rev())
+                .all(|it| it.0.as_str() == Some(it.1))
+        })
+    }
+
+    pub fn is_ignore(&self) -> bool {
+        self.by_key("ignore").exists()
+    }
+
+    pub fn is_bench(&self) -> bool {
+        self.by_key("bench").exists()
+    }
+
     pub fn is_unstable(&self) -> bool {
         self.by_key("unstable").exists()
     }
@@ -282,7 +304,7 @@ use std::slice::Iter as SliceIter;
 pub enum DocAtom {
     /// eg. `#[doc(hidden)]`
     Flag(SmolStr),
-    /// eg. `#[doc(alias = "x")]`
+    /// eg. `#[doc(alias = "it")]`
     ///
     /// Note that a key can have multiple values that are all considered "active" at the same time.
     /// For example, `#[doc(alias = "x")]` and `#[doc(alias = "y")]`.
@@ -462,6 +484,7 @@ impl AttrsWithOwner {
                 }
             },
             AttrDefId::ExternBlockId(it) => attrs_from_item_tree_loc(db, it),
+            AttrDefId::ExternCrateId(it) => attrs_from_item_tree_loc(db, it),
         };
 
         let attrs = raw_attrs.filter(db.upcast(), def.krate(db));
@@ -546,6 +569,7 @@ impl AttrsWithOwner {
                     .map(|source| ast::AnyHasAttrs::new(source[id.local_id].clone())),
             },
             AttrDefId::ExternBlockId(id) => any_has_attrs(db, id),
+            AttrDefId::ExternCrateId(id) => any_has_attrs(db, id),
         };
 
         AttrSourceMap::new(owner.as_ref().map(|node| node as &dyn HasAttrs))

crates/hir-def/src/body.rs

@@ -273,10 +273,10 @@ impl Body {
 
     pub fn is_binding_upvar(&self, binding: BindingId, relative_to: ExprId) -> bool {
         match self.binding_owners.get(&binding) {
-            Some(x) => {
+            Some(it) => {
                 // We assign expression ids in a way that outer closures will receive
                 // a lower id
-                x.into_raw() < relative_to.into_raw()
+                it.into_raw() < relative_to.into_raw()
             }
             None => true,
         }

crates/hir-def/src/body/lower.rs

@@ -297,11 +297,11 @@ impl ExprCollector<'_> {
                         let (result_expr_id, prev_binding_owner) =
                             this.initialize_binding_owner(syntax_ptr);
                         let inner_expr = this.collect_block(e);
-                        let x = this.db.intern_anonymous_const(ConstBlockLoc {
+                        let it = this.db.intern_anonymous_const(ConstBlockLoc {
                             parent: this.owner,
                             root: inner_expr,
                         });
-                        this.body.exprs[result_expr_id] = Expr::Const(x);
+                        this.body.exprs[result_expr_id] = Expr::Const(it);
                         this.current_binding_owner = prev_binding_owner;
                         result_expr_id
                     })
@@ -324,10 +324,10 @@ impl ExprCollector<'_> {
             ast::Expr::CallExpr(e) => {
                 let is_rustc_box = {
                     let attrs = e.attrs();
-                    attrs.filter_map(|x| x.as_simple_atom()).any(|x| x == "rustc_box")
+                    attrs.filter_map(|it| it.as_simple_atom()).any(|it| it == "rustc_box")
                 };
                 if is_rustc_box {
-                    let expr = self.collect_expr_opt(e.arg_list().and_then(|x| x.args().next()));
+                    let expr = self.collect_expr_opt(e.arg_list().and_then(|it| it.args().next()));
                     self.alloc_expr(Expr::Box { expr }, syntax_ptr)
                 } else {
                     let callee = self.collect_expr_opt(e.expr());
@@ -781,7 +781,7 @@ impl ExprCollector<'_> {
             pat: self.alloc_pat_desugared(some_pat),
             guard: None,
             expr: self.with_opt_labeled_rib(label, |this| {
-                this.collect_expr_opt(e.loop_body().map(|x| x.into()))
+                this.collect_expr_opt(e.loop_body().map(|it| it.into()))
             }),
         };
         let iter_name = Name::generate_new_name();
@@ -874,10 +874,10 @@ impl ExprCollector<'_> {
             }),
             guard: None,
             expr: {
-                let x = self.alloc_expr(Expr::Path(Path::from(break_name)), syntax_ptr.clone());
+                let it = self.alloc_expr(Expr::Path(Path::from(break_name)), syntax_ptr.clone());
                 let callee = self.alloc_expr(Expr::Path(try_from_residual), syntax_ptr.clone());
                 let result = self.alloc_expr(
-                    Expr::Call { callee, args: Box::new([x]), is_assignee_expr: false },
+                    Expr::Call { callee, args: Box::new([it]), is_assignee_expr: false },
                     syntax_ptr.clone(),
                 );
                 self.alloc_expr(
@@ -1240,12 +1240,12 @@ impl ExprCollector<'_> {
                 pats.push(self.collect_pat(first, binding_list));
                 binding_list.reject_new = true;
                 for rest in it {
-                    for (_, x) in binding_list.is_used.iter_mut() {
+                    for (_, it) in binding_list.is_used.iter_mut() {
-                        *x = false;
+                        *it = false;
                     }
                     pats.push(self.collect_pat(rest, binding_list));
-                    for (&id, &x) in binding_list.is_used.iter() {
+                    for (&id, &is_used) in binding_list.is_used.iter() {
-                        if !x {
+                        if !is_used {
                             self.body.bindings[id].problems =
                                 Some(BindingProblems::NotBoundAcrossAll);
                         }
@@ -1352,9 +1352,9 @@ impl ExprCollector<'_> {
             // FIXME: implement in a way that also builds source map and calculates assoc resolutions in type inference.
             ast::Pat::RangePat(p) => {
                 let mut range_part_lower = |p: Option<ast::Pat>| {
-                    p.and_then(|x| match &x {
+                    p.and_then(|it| match &it {
-                        ast::Pat::LiteralPat(x) => {
+                        ast::Pat::LiteralPat(it) => {
-                            Some(Box::new(LiteralOrConst::Literal(pat_literal_to_hir(x)?.0)))
+                            Some(Box::new(LiteralOrConst::Literal(pat_literal_to_hir(it)?.0)))
                         }
                         ast::Pat::IdentPat(p) => {
                             let name =
@@ -1451,9 +1451,7 @@ impl ExprCollector<'_> {
         &self,
         lifetime: Option<ast::Lifetime>,
     ) -> Result<Option<LabelId>, BodyDiagnostic> {
-        let Some(lifetime) = lifetime else {
+        let Some(lifetime) = lifetime else { return Ok(None) };
-            return Ok(None)
-        };
         let name = Name::new_lifetime(&lifetime);
 
         for (rib_idx, rib) in self.label_ribs.iter().enumerate().rev() {

crates/hir-def/src/body/pretty.rs

@@ -105,7 +105,7 @@ struct Printer<'a> {
     needs_indent: bool,
 }
 
-impl<'a> Write for Printer<'a> {
+impl Write for Printer<'_> {
     fn write_str(&mut self, s: &str) -> fmt::Result {
         for line in s.split_inclusive('\n') {
             if self.needs_indent {
@@ -125,7 +125,7 @@ impl<'a> Write for Printer<'a> {
     }
 }
 
-impl<'a> Printer<'a> {
+impl Printer<'_> {
     fn indented(&mut self, f: impl FnOnce(&mut Self)) {
         self.indent_level += 1;
         wln!(self);

crates/hir-def/src/body/tests.rs

@@ -3,12 +3,12 @@ mod block;
 use base_db::{fixture::WithFixture, SourceDatabase};
 use expect_test::Expect;
 
-use crate::ModuleDefId;
+use crate::{test_db::TestDB, ModuleDefId};
 
 use super::*;
 
 fn lower(ra_fixture: &str) -> Arc<Body> {
-    let db = crate::test_db::TestDB::with_files(ra_fixture);
+    let db = TestDB::with_files(ra_fixture);
 
     let krate = db.crate_graph().iter().next().unwrap();
     let def_map = db.crate_def_map(krate);
@@ -25,15 +25,15 @@ fn lower(ra_fixture: &str) -> Arc<Body> {
     db.body(fn_def.unwrap().into())
 }
 
-fn block_def_map_at(ra_fixture: &str) -> String {
+fn def_map_at(ra_fixture: &str) -> String {
-    let (db, position) = crate::test_db::TestDB::with_position(ra_fixture);
+    let (db, position) = TestDB::with_position(ra_fixture);
 
     let module = db.module_at_position(position);
     module.def_map(&db).dump(&db)
 }
 
 fn check_block_scopes_at(ra_fixture: &str, expect: Expect) {
-    let (db, position) = crate::test_db::TestDB::with_position(ra_fixture);
+    let (db, position) = TestDB::with_position(ra_fixture);
 
     let module = db.module_at_position(position);
     let actual = module.def_map(&db).dump_block_scopes(&db);
@@ -41,7 +41,7 @@ fn check_block_scopes_at(ra_fixture: &str, expect: Expect) {
 }
 
 fn check_at(ra_fixture: &str, expect: Expect) {
-    let actual = block_def_map_at(ra_fixture);
+    let actual = def_map_at(ra_fixture);
     expect.assert_eq(&actual);
 }
 

crates/hir-def/src/body/tests/block.rs

@@ -133,6 +133,47 @@ struct Struct {}
     );
 }
 
+#[test]
+fn super_imports_2() {
+    check_at(
+        r#"
+fn outer() {
+    mod m {
+        struct ResolveMe {}
+        fn middle() {
+            mod m2 {
+                fn inner() {
+                    use super::ResolveMe;
+                    $0
+                }
+            }
+        }
+    }
+}
+"#,
+        expect![[r#"
+            block scope
+            ResolveMe: t
+
+            block scope
+            m2: t
+
+            block scope::m2
+            inner: v
+
+            block scope
+            m: t
+
+            block scope::m
+            ResolveMe: t
+            middle: v
+
+            crate
+            outer: v
+        "#]],
+    );
+}
+
 #[test]
 fn nested_module_scoping() {
     check_block_scopes_at(
@@ -155,6 +196,42 @@ fn f() {
     );
 }
 
+#[test]
+fn self_imports() {
+    check_at(
+        r#"
+fn f() {
+    mod m {
+        struct ResolveMe {}
+        fn g() {
+            fn h() {
+                use self::ResolveMe;
+                $0
+            }
+        }
+    }
+}
+"#,
+        expect![[r#"
+            block scope
+            ResolveMe: t
+
+            block scope
+            h: v
+
+            block scope
+            m: t
+
+            block scope::m
+            ResolveMe: t
+            g: v
+
+            crate
+            f: v
+        "#]],
+    );
+}
+
 #[test]
 fn legacy_macro_items() {
     // Checks that legacy-scoped `macro_rules!` from parent namespaces are resolved and expanded

crates/hir-def/src/data.rs

@@ -24,11 +24,12 @@ use crate::{
         proc_macro::{parse_macro_name_and_helper_attrs, ProcMacroKind},
         DefMap, MacroSubNs,
     },
+    path::ImportAlias,
     type_ref::{TraitRef, TypeBound, TypeRef},
     visibility::RawVisibility,
-    AssocItemId, AstIdWithPath, ConstId, ConstLoc, FunctionId, FunctionLoc, HasModule, ImplId,
+    AssocItemId, AstIdWithPath, ConstId, ConstLoc, ExternCrateId, FunctionId, FunctionLoc,
-    Intern, ItemContainerId, ItemLoc, Lookup, Macro2Id, MacroRulesId, ModuleId, ProcMacroId,
+    HasModule, ImplId, Intern, ItemContainerId, ItemLoc, Lookup, Macro2Id, MacroRulesId, ModuleId,
-    StaticId, TraitAliasId, TraitId, TypeAliasId, TypeAliasLoc,
+    ProcMacroId, StaticId, TraitAliasId, TraitId, TypeAliasId, TypeAliasLoc,
 };
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -424,6 +425,7 @@ impl MacroRulesData {
         Arc::new(MacroRulesData { name: makro.name.clone(), macro_export })
     }
 }
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ProcMacroData {
     pub name: Name,
@@ -460,6 +462,30 @@ impl ProcMacroData {
     }
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ExternCrateDeclData {
+    pub name: Name,
+    pub alias: Option<ImportAlias>,
+    pub visibility: RawVisibility,
+}
+
+impl ExternCrateDeclData {
+    pub(crate) fn extern_crate_decl_data_query(
+        db: &dyn DefDatabase,
+        extern_crate: ExternCrateId,
+    ) -> Arc<ExternCrateDeclData> {
+        let loc = extern_crate.lookup(db);
+        let item_tree = loc.id.item_tree(db);
+        let extern_crate = &item_tree[loc.id.value];
+
+        Arc::new(Self {
+            name: extern_crate.name.clone(),
+            visibility: item_tree[extern_crate.visibility].clone(),
+            alias: extern_crate.alias.clone(),
+        })
+    }
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ConstData {
     /// `None` for `const _: () = ();`
@@ -573,7 +599,7 @@ impl<'a> AssocItemCollector<'a> {
             if !attrs.is_cfg_enabled(self.expander.cfg_options()) {
                 self.diagnostics.push(DefDiagnostic::unconfigured_code(
                     self.module_id.local_id,
-                    InFile::new(self.expander.current_file_id(), item.ast_id(item_tree).upcast()),
+                    InFile::new(self.expander.current_file_id(), item.ast_id(item_tree).erase()),
                     attrs.cfg().unwrap(),
                     self.expander.cfg_options().clone(),
                 ));

crates/hir-def/src/data/adt.rs

@@ -18,7 +18,6 @@ use triomphe::Arc;
 use crate::{
     builtin_type::{BuiltinInt, BuiltinUint},
     db::DefDatabase,
-    expander::CfgExpander,
     item_tree::{AttrOwner, Field, FieldAstId, Fields, ItemTree, ModItem, RawVisibilityId},
     lang_item::LangItem,
     lower::LowerCtx,
@@ -29,8 +28,8 @@ use crate::{
     tt::{Delimiter, DelimiterKind, Leaf, Subtree, TokenTree},
     type_ref::TypeRef,
     visibility::RawVisibility,
-    EnumId, LocalEnumVariantId, LocalFieldId, LocalModuleId, Lookup, ModuleId, StructId, UnionId,
+    EnumId, EnumLoc, LocalEnumVariantId, LocalFieldId, LocalModuleId, Lookup, ModuleId, StructId,
-    VariantId,
+    UnionId, VariantId,
 };
 
 /// Note that we use `StructData` for unions as well!
@@ -76,6 +75,7 @@ pub struct EnumData {
 pub struct EnumVariantData {
     pub name: Name,
     pub variant_data: Arc<VariantData>,
+    pub tree_id: la_arena::Idx<crate::item_tree::Variant>,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -147,6 +147,7 @@ fn parse_repr_tt(tt: &Subtree) -> Option<ReprOptions> {
                 }
                 "C" => ReprFlags::IS_C,
                 "transparent" => ReprFlags::IS_TRANSPARENT,
+                "simd" => ReprFlags::IS_SIMD,
                 repr => {
                     if let Some(builtin) = BuiltinInt::from_suffix(repr)
                         .map(Either::Left)
@@ -325,11 +326,12 @@ impl EnumData {
                 variants.alloc(EnumVariantData {
                     name: var.name.clone(),
                     variant_data: Arc::new(var_data),
+                    tree_id,
                 });
             } else {
                 diagnostics.push(DefDiagnostic::unconfigured_code(
                     loc.container.local_id,
-                    InFile::new(loc.id.file_id(), var.ast_id.upcast()),
+                    InFile::new(loc.id.file_id(), var.ast_id.erase()),
                     attrs.cfg().unwrap(),
                     cfg_options.clone(),
                 ))
@@ -367,9 +369,10 @@ impl HasChildSource<LocalEnumVariantId> for EnumId {
         &self,
         db: &dyn DefDatabase,
     ) -> InFile<ArenaMap<LocalEnumVariantId, Self::Value>> {
-        let src = self.lookup(db).source(db);
+        let loc = &self.lookup(db);
+        let src = loc.source(db);
         let mut trace = Trace::new_for_map();
-        lower_enum(db, &mut trace, &src, self.lookup(db).container);
+        lower_enum(db, &mut trace, &src, loc);
         src.with_value(trace.into_map())
     }
 }
@@ -378,31 +381,58 @@ fn lower_enum(
     db: &dyn DefDatabase,
     trace: &mut Trace<EnumVariantData, ast::Variant>,
     ast: &InFile<ast::Enum>,
-    module_id: ModuleId,
+    loc: &EnumLoc,
 ) {
-    let expander = CfgExpander::new(db, ast.file_id, module_id.krate);
+    let item_tree = loc.id.item_tree(db);
+    let krate = loc.container.krate;
+
+    let item_tree_variants = item_tree[loc.id.value].variants.clone();
+
+    let cfg_options = &db.crate_graph()[krate].cfg_options;
     let variants = ast
         .value
         .variant_list()
         .into_iter()
         .flat_map(|it| it.variants())
-        .filter(|var| expander.is_cfg_enabled(db, var));
+        .zip(item_tree_variants)
-    for var in variants {
+        .filter(|&(_, item_tree_id)| {
+            item_tree.attrs(db, krate, item_tree_id.into()).is_cfg_enabled(cfg_options)
+        });
+    for (var, item_tree_id) in variants {
         trace.alloc(
             || var.clone(),
             || EnumVariantData {
                 name: var.name().map_or_else(Name::missing, |it| it.as_name()),
-                variant_data: Arc::new(VariantData::new(db, ast.with_value(var.kind()), module_id)),
+                variant_data: Arc::new(VariantData::new(
+                    db,
+                    ast.with_value(var.kind()),
+                    loc.container,
+                    &item_tree,
+                    item_tree_id,
+                )),
+                tree_id: item_tree_id,
             },
         );
     }
 }
 
 impl VariantData {
-    fn new(db: &dyn DefDatabase, flavor: InFile<ast::StructKind>, module_id: ModuleId) -> Self {
+    fn new(
-        let mut expander = CfgExpander::new(db, flavor.file_id, module_id.krate);
+        db: &dyn DefDatabase,
+        flavor: InFile<ast::StructKind>,
+        module_id: ModuleId,
+        item_tree: &ItemTree,
+        variant: la_arena::Idx<crate::item_tree::Variant>,
+    ) -> Self {
         let mut trace = Trace::new_for_arena();
-        match lower_struct(db, &mut expander, &mut trace, &flavor) {
+        match lower_struct(
+            db,
+            &mut trace,
+            &flavor,
+            module_id.krate,
+            item_tree,
+            &item_tree[variant].fields,
+        ) {
             StructKind::Tuple => VariantData::Tuple(trace.into_arena()),
             StructKind::Record => VariantData::Record(trace.into_arena()),
             StructKind::Unit => VariantData::Unit,
@@ -434,28 +464,43 @@ impl HasChildSource<LocalFieldId> for VariantId {
     type Value = Either<ast::TupleField, ast::RecordField>;
 
     fn child_source(&self, db: &dyn DefDatabase) -> InFile<ArenaMap<LocalFieldId, Self::Value>> {
-        let (src, module_id) = match self {
+        let item_tree;
+        let (src, fields, container) = match *self {
             VariantId::EnumVariantId(it) => {
                 // I don't really like the fact that we call into parent source
                 // here, this might add to more queries then necessary.
+                let lookup = it.parent.lookup(db);
+                item_tree = lookup.id.item_tree(db);
                 let src = it.parent.child_source(db);
-                (src.map(|map| map[it.local_id].kind()), it.parent.lookup(db).container)
+                let tree_id = db.enum_data(it.parent).variants[it.local_id].tree_id;
+                let fields = &item_tree[tree_id].fields;
+                (src.map(|map| map[it.local_id].kind()), fields, lookup.container)
             }
             VariantId::StructId(it) => {
-                (it.lookup(db).source(db).map(|it| it.kind()), it.lookup(db).container)
+                let lookup = it.lookup(db);
+                item_tree = lookup.id.item_tree(db);
+                (
+                    lookup.source(db).map(|it| it.kind()),
+                    &item_tree[lookup.id.value].fields,
+                    lookup.container,
+                )
+            }
+            VariantId::UnionId(it) => {
+                let lookup = it.lookup(db);
+                item_tree = lookup.id.item_tree(db);
+                (
+                    lookup.source(db).map(|it| {
+                        it.record_field_list()
+                            .map(ast::StructKind::Record)
+                            .unwrap_or(ast::StructKind::Unit)
+                    }),
+                    &item_tree[lookup.id.value].fields,
+                    lookup.container,
+                )
             }
-            VariantId::UnionId(it) => (
-                it.lookup(db).source(db).map(|it| {
-                    it.record_field_list()
-                        .map(ast::StructKind::Record)
-                        .unwrap_or(ast::StructKind::Unit)
-                }),
-                it.lookup(db).container,
-            ),
         };
-        let mut expander = CfgExpander::new(db, src.file_id, module_id.krate);
         let mut trace = Trace::new_for_map();
-        lower_struct(db, &mut expander, &mut trace, &src);
+        lower_struct(db, &mut trace, &src, container.krate, &item_tree, fields);
         src.with_value(trace.into_map())
     }
 }
@@ -469,16 +514,19 @@ pub enum StructKind {
 
 fn lower_struct(
     db: &dyn DefDatabase,
-    expander: &mut CfgExpander,
     trace: &mut Trace<FieldData, Either<ast::TupleField, ast::RecordField>>,
     ast: &InFile<ast::StructKind>,
+    krate: CrateId,
+    item_tree: &ItemTree,
+    fields: &Fields,
 ) -> StructKind {
-    let ctx = LowerCtx::new(db, &expander.hygiene(), ast.file_id);
+    let ctx = LowerCtx::with_file_id(db, ast.file_id);
 
-    match &ast.value {
+    match (&ast.value, fields) {
-        ast::StructKind::Tuple(fl) => {
+        (ast::StructKind::Tuple(fl), Fields::Tuple(fields)) => {
-            for (i, fd) in fl.fields().enumerate() {
+            let cfg_options = &db.crate_graph()[krate].cfg_options;
-                if !expander.is_cfg_enabled(db, &fd) {
+            for ((i, fd), item_tree_id) in fl.fields().enumerate().zip(fields.clone()) {
+                if !item_tree.attrs(db, krate, item_tree_id.into()).is_cfg_enabled(cfg_options) {
                     continue;
                 }
 
@@ -493,9 +541,10 @@ fn lower_struct(
             }
             StructKind::Tuple
         }
-        ast::StructKind::Record(fl) => {
+        (ast::StructKind::Record(fl), Fields::Record(fields)) => {
-            for fd in fl.fields() {
+            let cfg_options = &db.crate_graph()[krate].cfg_options;
-                if !expander.is_cfg_enabled(db, &fd) {
+            for (fd, item_tree_id) in fl.fields().zip(fields.clone()) {
+                if !item_tree.attrs(db, krate, item_tree_id.into()).is_cfg_enabled(cfg_options) {
                     continue;
                 }
 
@@ -510,7 +559,7 @@ fn lower_struct(
             }
             StructKind::Record
         }
-        ast::StructKind::Unit => StructKind::Unit,
+        _ => StructKind::Unit,
     }
 }
 
@@ -539,8 +588,8 @@ fn lower_fields(
                         InFile::new(
                             current_file_id,
                             match field.ast_id {
-                                FieldAstId::Record(it) => it.upcast(),
+                                FieldAstId::Record(it) => it.erase(),
-                                FieldAstId::Tuple(it) => it.upcast(),
+                                FieldAstId::Tuple(it) => it.erase(),
                             },
                         ),
                         attrs.cfg().unwrap(),
@@ -563,8 +612,8 @@ fn lower_fields(
                         InFile::new(
                             current_file_id,
                             match field.ast_id {
-                                FieldAstId::Record(it) => it.upcast(),
+                                FieldAstId::Record(it) => it.erase(),
-                                FieldAstId::Tuple(it) => it.upcast(),
+                                FieldAstId::Tuple(it) => it.erase(),
                             },
                         ),
                         attrs.cfg().unwrap(),

crates/hir-def/src/db.rs

@@ -12,27 +12,31 @@ use crate::{
     body::{scope::ExprScopes, Body, BodySourceMap},
     data::{
         adt::{EnumData, StructData},
-        ConstData, FunctionData, ImplData, Macro2Data, MacroRulesData, ProcMacroData, StaticData,
+        ConstData, ExternCrateDeclData, FunctionData, ImplData, Macro2Data, MacroRulesData,
-        TraitAliasData, TraitData, TypeAliasData,
+        ProcMacroData, StaticData, TraitAliasData, TraitData, TypeAliasData,
     },
     generics::GenericParams,
     import_map::ImportMap,
     item_tree::{AttrOwner, ItemTree},
-    lang_item::{LangItem, LangItemTarget, LangItems},
+    lang_item::{self, LangItem, LangItemTarget, LangItems},
     nameres::{diagnostics::DefDiagnostic, DefMap},
     visibility::{self, Visibility},
     AttrDefId, BlockId, BlockLoc, ConstBlockId, ConstBlockLoc, ConstId, ConstLoc, DefWithBodyId,
-    EnumId, EnumLoc, ExternBlockId, ExternBlockLoc, FunctionId, FunctionLoc, GenericDefId, ImplId,
+    EnumId, EnumLoc, ExternBlockId, ExternBlockLoc, ExternCrateId, ExternCrateLoc, FunctionId,
-    ImplLoc, InTypeConstId, InTypeConstLoc, LocalEnumVariantId, LocalFieldId, Macro2Id, Macro2Loc,
+    FunctionLoc, GenericDefId, ImplId, ImplLoc, ImportId, ImportLoc, InTypeConstId, InTypeConstLoc,
-    MacroRulesId, MacroRulesLoc, ProcMacroId, ProcMacroLoc, StaticId, StaticLoc, StructId,
+    LocalEnumVariantId, LocalFieldId, Macro2Id, Macro2Loc, MacroRulesId, MacroRulesLoc,
-    StructLoc, TraitAliasId, TraitAliasLoc, TraitId, TraitLoc, TypeAliasId, TypeAliasLoc, UnionId,
+    ProcMacroId, ProcMacroLoc, StaticId, StaticLoc, StructId, StructLoc, TraitAliasId,
-    UnionLoc, VariantId,
+    TraitAliasLoc, TraitId, TraitLoc, TypeAliasId, TypeAliasLoc, UnionId, UnionLoc, VariantId,
 };
 
 #[salsa::query_group(InternDatabaseStorage)]
 pub trait InternDatabase: SourceDatabase {
     // region: items
     #[salsa::interned]
+    fn intern_import(&self, loc: ImportLoc) -> ImportId;
+    #[salsa::interned]
+    fn intern_extern_crate(&self, loc: ExternCrateLoc) -> ExternCrateId;
+    #[salsa::interned]
     fn intern_function(&self, loc: FunctionLoc) -> FunctionId;
     #[salsa::interned]
     fn intern_struct(&self, loc: StructLoc) -> StructId;
@@ -160,6 +164,9 @@ pub trait DefDatabase: InternDatabase + ExpandDatabase + Upcast<dyn ExpandDataba
     #[salsa::invoke(ProcMacroData::proc_macro_data_query)]
     fn proc_macro_data(&self, makro: ProcMacroId) -> Arc<ProcMacroData>;
 
+    #[salsa::invoke(ExternCrateDeclData::extern_crate_decl_data_query)]
+    fn extern_crate_decl_data(&self, extern_crate: ExternCrateId) -> Arc<ExternCrateDeclData>;
+
     // endregion:data
 
     #[salsa::invoke(Body::body_with_source_map_query)]
@@ -197,6 +204,9 @@ pub trait DefDatabase: InternDatabase + ExpandDatabase + Upcast<dyn ExpandDataba
     #[salsa::invoke(AttrsWithOwner::attrs_query)]
     fn attrs(&self, def: AttrDefId) -> Attrs;
 
+    #[salsa::invoke(lang_item::lang_attr_query)]
+    fn lang_attr(&self, def: AttrDefId) -> Option<LangItem>;
+
     #[salsa::transparent]
     #[salsa::invoke(AttrsWithOwner::attrs_with_owner)]
     fn attrs_with_owner(&self, def: AttrDefId) -> AttrsWithOwner;

crates/hir-def/src/dyn_map/keys.rs

@@ -8,8 +8,8 @@ use syntax::{ast, AstNode, AstPtr};
 
 use crate::{
     dyn_map::{DynMap, Policy},
-    ConstId, EnumId, EnumVariantId, FieldId, FunctionId, ImplId, LifetimeParamId, Macro2Id,
+    ConstId, EnumId, EnumVariantId, ExternCrateId, FieldId, FunctionId, ImplId, LifetimeParamId,
-    MacroRulesId, ProcMacroId, StaticId, StructId, TraitAliasId, TraitId, TypeAliasId,
+    Macro2Id, MacroRulesId, ProcMacroId, StaticId, StructId, TraitAliasId, TraitId, TypeAliasId,
     TypeOrConstParamId, UnionId,
 };
 
@@ -25,6 +25,7 @@ pub const TRAIT_ALIAS: Key<ast::TraitAlias, TraitAliasId> = Key::new();
 pub const STRUCT: Key<ast::Struct, StructId> = Key::new();
 pub const UNION: Key<ast::Union, UnionId> = Key::new();
 pub const ENUM: Key<ast::Enum, EnumId> = Key::new();
+pub const EXTERN_CRATE: Key<ast::ExternCrate, ExternCrateId> = Key::new();
 
 pub const VARIANT: Key<ast::Variant, EnumVariantId> = Key::new();
 pub const TUPLE_FIELD: Key<ast::TupleField, FieldId> = Key::new();

crates/hir-def/src/expander.rs

@@ -15,18 +15,11 @@ use crate::{
     MacroId, ModuleId,
 };
 
-/// A subset of Expander that only deals with cfg attributes. We only need it to
-/// avoid cyclic queries in crate def map during enum processing.
 #[derive(Debug)]
-pub(crate) struct CfgExpander {
+pub struct Expander {
     cfg_options: CfgOptions,
     hygiene: Hygiene,
     krate: CrateId,
-}
-
-#[derive(Debug)]
-pub struct Expander {
-    cfg_expander: CfgExpander,
     pub(crate) current_file_id: HirFileId,
     pub(crate) module: ModuleId,
     /// `recursion_depth == usize::MAX` indicates that the recursion limit has been reached.
@@ -34,41 +27,23 @@ pub struct Expander {
     recursion_limit: Limit,
 }
 
-impl CfgExpander {
-    pub(crate) fn new(
-        db: &dyn DefDatabase,
-        current_file_id: HirFileId,
-        krate: CrateId,
-    ) -> CfgExpander {
-        let hygiene = Hygiene::new(db.upcast(), current_file_id);
-        let cfg_options = db.crate_graph()[krate].cfg_options.clone();
-        CfgExpander { cfg_options, hygiene, krate }
-    }
-
-    pub(crate) fn parse_attrs(&self, db: &dyn DefDatabase, owner: &dyn ast::HasAttrs) -> Attrs {
-        Attrs::filter(db, self.krate, RawAttrs::new(db.upcast(), owner, &self.hygiene))
-    }
-
-    pub(crate) fn is_cfg_enabled(&self, db: &dyn DefDatabase, owner: &dyn ast::HasAttrs) -> bool {
-        let attrs = self.parse_attrs(db, owner);
-        attrs.is_cfg_enabled(&self.cfg_options)
-    }
-
-    pub(crate) fn hygiene(&self) -> &Hygiene {
-        &self.hygiene
-    }
-}
-
 impl Expander {
     pub fn new(db: &dyn DefDatabase, current_file_id: HirFileId, module: ModuleId) -> Expander {
-        let cfg_expander = CfgExpander::new(db, current_file_id, module.krate);
         let recursion_limit = db.recursion_limit(module.krate);
         #[cfg(not(test))]
         let recursion_limit = Limit::new(recursion_limit as usize);
         // Without this, `body::tests::your_stack_belongs_to_me` stack-overflows in debug
         #[cfg(test)]
         let recursion_limit = Limit::new(std::cmp::min(32, recursion_limit as usize));
-        Expander { cfg_expander, current_file_id, module, recursion_depth: 0, recursion_limit }
+        Expander {
+            current_file_id,
+            module,
+            recursion_depth: 0,
+            recursion_limit,
+            cfg_options: db.crate_graph()[module.krate].cfg_options.clone(),
+            hygiene: Hygiene::new(db.upcast(), current_file_id),
+            krate: module.krate,
+        }
     }
 
     pub fn enter_expand<T: ast::AstNode>(
@@ -120,7 +95,7 @@ impl Expander {
     }
 
     pub fn exit(&mut self, db: &dyn DefDatabase, mut mark: Mark) {
-        self.cfg_expander.hygiene = Hygiene::new(db.upcast(), mark.file_id);
+        self.hygiene = Hygiene::new(db.upcast(), mark.file_id);
         self.current_file_id = mark.file_id;
         if self.recursion_depth == u32::MAX {
             // Recursion limit has been reached somewhere in the macro expansion tree. Reset the
@@ -135,7 +110,7 @@ impl Expander {
     }
 
     pub fn ctx<'a>(&self, db: &'a dyn DefDatabase) -> LowerCtx<'a> {
-        LowerCtx::new(db, &self.cfg_expander.hygiene, self.current_file_id)
+        LowerCtx::new(db, &self.hygiene, self.current_file_id)
     }
 
     pub(crate) fn to_source<T>(&self, value: T) -> InFile<T> {
@@ -143,11 +118,11 @@ impl Expander {
     }
 
     pub(crate) fn parse_attrs(&self, db: &dyn DefDatabase, owner: &dyn ast::HasAttrs) -> Attrs {
-        self.cfg_expander.parse_attrs(db, owner)
+        Attrs::filter(db, self.krate, RawAttrs::new(db.upcast(), owner, &self.hygiene))
     }
 
     pub(crate) fn cfg_options(&self) -> &CfgOptions {
-        &self.cfg_expander.cfg_options
+        &self.cfg_options
     }
 
     pub fn current_file_id(&self) -> HirFileId {
@@ -155,7 +130,7 @@ impl Expander {
     }
 
     pub(crate) fn parse_path(&mut self, db: &dyn DefDatabase, path: ast::Path) -> Option<Path> {
-        let ctx = LowerCtx::new(db, &self.cfg_expander.hygiene, self.current_file_id);
+        let ctx = LowerCtx::new(db, &self.hygiene, self.current_file_id);
         Path::from_src(path, &ctx)
     }
 
@@ -194,7 +169,7 @@ impl Expander {
                 let parse = value.cast::<T>()?;
 
                 self.recursion_depth += 1;
-                self.cfg_expander.hygiene = Hygiene::new(db.upcast(), file_id);
+                self.hygiene = Hygiene::new(db.upcast(), file_id);
                 let old_file_id = std::mem::replace(&mut self.current_file_id, file_id);
                 let mark =
                     Mark { file_id: old_file_id, bomb: DropBomb::new("expansion mark dropped") };

crates/hir-def/src/find_path.rs

@@ -360,7 +360,7 @@ fn calculate_best_path(
                     prefer_no_std,
                 )?;
                 cov_mark::hit!(partially_imported);
-                path.push_segment(info.path.segments.last()?.clone());
+                path.push_segment(info.name.clone());
                 Some(path)
             })
         });

crates/hir-def/src/generics.rs

@@ -67,21 +67,21 @@ pub enum TypeOrConstParamData {
 impl TypeOrConstParamData {
     pub fn name(&self) -> Option<&Name> {
         match self {
-            TypeOrConstParamData::TypeParamData(x) => x.name.as_ref(),
+            TypeOrConstParamData::TypeParamData(it) => it.name.as_ref(),
-            TypeOrConstParamData::ConstParamData(x) => Some(&x.name),
+            TypeOrConstParamData::ConstParamData(it) => Some(&it.name),
         }
     }
 
     pub fn has_default(&self) -> bool {
         match self {
-            TypeOrConstParamData::TypeParamData(x) => x.default.is_some(),
+            TypeOrConstParamData::TypeParamData(it) => it.default.is_some(),
-            TypeOrConstParamData::ConstParamData(x) => x.has_default,
+            TypeOrConstParamData::ConstParamData(it) => it.has_default,
         }
     }
 
     pub fn type_param(&self) -> Option<&TypeParamData> {
         match self {
-            TypeOrConstParamData::TypeParamData(x) => Some(x),
+            TypeOrConstParamData::TypeParamData(it) => Some(it),
             TypeOrConstParamData::ConstParamData(_) => None,
         }
     }
@@ -89,14 +89,14 @@ impl TypeOrConstParamData {
     pub fn const_param(&self) -> Option<&ConstParamData> {
         match self {
             TypeOrConstParamData::TypeParamData(_) => None,
-            TypeOrConstParamData::ConstParamData(x) => Some(x),
+            TypeOrConstParamData::ConstParamData(it) => Some(it),
         }
     }
 
     pub fn is_trait_self(&self) -> bool {
         match self {
-            TypeOrConstParamData::TypeParamData(x) => {
+            TypeOrConstParamData::TypeParamData(it) => {
-                x.provenance == TypeParamProvenance::TraitSelf
+                it.provenance == TypeParamProvenance::TraitSelf
             }
             TypeOrConstParamData::ConstParamData(_) => false,
         }

crates/hir-def/src/hir/type_ref.rs

@@ -425,8 +425,8 @@ impl ConstRef {
         }
         match expr {
             ast::Expr::PathExpr(p) if is_path_ident(&p) => {
-                match p.path().and_then(|x| x.segment()).and_then(|x| x.name_ref()) {
+                match p.path().and_then(|it| it.segment()).and_then(|it| it.name_ref()) {
-                    Some(x) => Self::Path(x.as_name()),
+                    Some(it) => Self::Path(it.as_name()),
                     None => Self::Scalar(LiteralConstRef::Unknown),
                 }
             }

crates/hir-def/src/import_map.rs

@@ -1,13 +1,14 @@
 //! A map of all publicly exported items in a crate.
 
+use std::collections::hash_map::Entry;
 use std::{fmt, hash::BuildHasherDefault};
 
 use base_db::CrateId;
 use fst::{self, Streamer};
 use hir_expand::name::Name;
-use indexmap::{map::Entry, IndexMap};
+use indexmap::IndexMap;
 use itertools::Itertools;
-use rustc_hash::{FxHashSet, FxHasher};
+use rustc_hash::{FxHashMap, FxHashSet, FxHasher};
 use triomphe::Arc;
 
 use crate::{
@@ -17,52 +18,23 @@ use crate::{
 
 type FxIndexMap<K, V> = IndexMap<K, V, BuildHasherDefault<FxHasher>>;
 
+// FIXME: Support aliases: an item may be exported under multiple names, so `ImportInfo` should
+// have `Vec<(Name, ModuleId)>` instead of `(Name, ModuleId)`.
 /// Item import details stored in the `ImportMap`.
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub struct ImportInfo {
-    /// A path that can be used to import the item, relative to the crate's root.
+    /// A name that can be used to import the item, relative to the crate's root.
-    pub path: ImportPath,
+    pub name: Name,
     /// The module containing this item.
     pub container: ModuleId,
     /// Whether the import is a trait associated item or not.
     pub is_trait_assoc_item: bool,
 }
 
-#[derive(Debug, Clone, Eq, PartialEq)]
+/// A map from publicly exported items to its name.
-pub struct ImportPath {
-    pub segments: Vec<Name>,
-}
-
-impl ImportPath {
-    pub fn display<'a>(&'a self, db: &'a dyn DefDatabase) -> impl fmt::Display + 'a {
-        struct Display<'a> {
-            db: &'a dyn DefDatabase,
-            path: &'a ImportPath,
-        }
-        impl fmt::Display for Display<'_> {
-            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-                fmt::Display::fmt(
-                    &self.path.segments.iter().map(|it| it.display(self.db.upcast())).format("::"),
-                    f,
-                )
-            }
-        }
-        Display { db, path: self }
-    }
-
-    fn len(&self) -> usize {
-        self.segments.len()
-    }
-}
-
-/// A map from publicly exported items to the path needed to import/name them from a downstream
-/// crate.
 ///
 /// Reexports of items are taken into account, ie. if something is exported under multiple
 /// names, the one with the shortest import path will be used.
-///
-/// Note that all paths are relative to the containing crate's root, so the crate name still needs
-/// to be prepended to the `ModPath` before the path is valid.
 #[derive(Default)]
 pub struct ImportMap {
     map: FxIndexMap<ItemInNs, ImportInfo>,
@@ -70,122 +42,58 @@ pub struct ImportMap {
     /// List of keys stored in `map`, sorted lexicographically by their `ModPath`. Indexed by the
     /// values returned by running `fst`.
     ///
-    /// Since a path can refer to multiple items due to namespacing, we store all items with the
+    /// Since a name can refer to multiple items due to namespacing, we store all items with the
-    /// same path right after each other. This allows us to find all items after the FST gives us
+    /// same name right after each other. This allows us to find all items after the FST gives us
     /// the index of the first one.
     importables: Vec<ItemInNs>,
     fst: fst::Map<Vec<u8>>,
 }
 
 impl ImportMap {
-    pub fn import_map_query(db: &dyn DefDatabase, krate: CrateId) -> Arc<Self> {
+    pub(crate) fn import_map_query(db: &dyn DefDatabase, krate: CrateId) -> Arc<Self> {
         let _p = profile::span("import_map_query");
 
-        let mut import_map = collect_import_map(db, krate);
+        let map = collect_import_map(db, krate);
 
-        let mut importables = import_map
+        let mut importables: Vec<_> = map
-            .map
             .iter()
-            .map(|(item, info)| (item, fst_path(db, &info.path)))
+            // We've only collected items, whose name cannot be tuple field.
-            .collect::<Vec<_>>();
+            .map(|(&item, info)| (item, info.name.as_str().unwrap().to_ascii_lowercase()))
-        importables.sort_by(|(_, fst_path), (_, fst_path2)| fst_path.cmp(fst_path2));
+            .collect();
+        importables.sort_by(|(_, lhs_name), (_, rhs_name)| lhs_name.cmp(rhs_name));
 
         // Build the FST, taking care not to insert duplicate values.
-
         let mut builder = fst::MapBuilder::memory();
-        let mut last_batch_start = 0;
+        let iter = importables.iter().enumerate().dedup_by(|lhs, rhs| lhs.1 .1 == rhs.1 .1);
-
+        for (start_idx, (_, name)) in iter {
-        for idx in 0..importables.len() {
+            let _ = builder.insert(name, start_idx as u64);
-            let key = &importables[last_batch_start].1;
-            if let Some((_, fst_path)) = importables.get(idx + 1) {
-                if key == fst_path {
-                    continue;
-                }
-            }
-
-            let _ = builder.insert(key, last_batch_start as u64);
-
-            last_batch_start = idx + 1;
         }
 
-        import_map.fst = builder.into_map();
+        Arc::new(ImportMap {
-        import_map.importables = importables.iter().map(|&(&item, _)| item).collect();
+            map,
-
+            fst: builder.into_map(),
-        Arc::new(import_map)
+            importables: importables.into_iter().map(|(item, _)| item).collect(),
-    }
+        })
-
-    /// Returns the `ModPath` needed to import/mention `item`, relative to this crate's root.
-    pub fn path_of(&self, item: ItemInNs) -> Option<&ImportPath> {
-        self.import_info_for(item).map(|it| &it.path)
     }
 
     pub fn import_info_for(&self, item: ItemInNs) -> Option<&ImportInfo> {
         self.map.get(&item)
     }
-
-    #[cfg(test)]
-    fn fmt_for_test(&self, db: &dyn DefDatabase) -> String {
-        let mut importable_paths: Vec<_> = self
-            .map
-            .iter()
-            .map(|(item, info)| {
-                let ns = match item {
-                    ItemInNs::Types(_) => "t",
-                    ItemInNs::Values(_) => "v",
-                    ItemInNs::Macros(_) => "m",
-                };
-                format!("- {} ({ns})", info.path.display(db))
-            })
-            .collect();
-
-        importable_paths.sort();
-        importable_paths.join("\n")
-    }
-
-    fn collect_trait_assoc_items(
-        &mut self,
-        db: &dyn DefDatabase,
-        tr: TraitId,
-        is_type_in_ns: bool,
-        original_import_info: &ImportInfo,
-    ) {
-        let _p = profile::span("collect_trait_assoc_items");
-        for (assoc_item_name, item) in &db.trait_data(tr).items {
-            let module_def_id = match item {
-                AssocItemId::FunctionId(f) => ModuleDefId::from(*f),
-                AssocItemId::ConstId(c) => ModuleDefId::from(*c),
-                // cannot use associated type aliases directly: need a `<Struct as Trait>::TypeAlias`
-                // qualifier, ergo no need to store it for imports in import_map
-                AssocItemId::TypeAliasId(_) => {
-                    cov_mark::hit!(type_aliases_ignored);
-                    continue;
-                }
-            };
-            let assoc_item = if is_type_in_ns {
-                ItemInNs::Types(module_def_id)
-            } else {
-                ItemInNs::Values(module_def_id)
-            };
-
-            let mut assoc_item_info = original_import_info.clone();
-            assoc_item_info.path.segments.push(assoc_item_name.to_owned());
-            assoc_item_info.is_trait_assoc_item = true;
-            self.map.insert(assoc_item, assoc_item_info);
-        }
-    }
 }
 
-fn collect_import_map(db: &dyn DefDatabase, krate: CrateId) -> ImportMap {
+fn collect_import_map(db: &dyn DefDatabase, krate: CrateId) -> FxIndexMap<ItemInNs, ImportInfo> {
     let _p = profile::span("collect_import_map");
 
     let def_map = db.crate_def_map(krate);
-    let mut import_map = ImportMap::default();
+    let mut map = FxIndexMap::default();
 
     // We look only into modules that are public(ly reexported), starting with the crate root.
-    let empty = ImportPath { segments: vec![] };
     let root = def_map.module_id(DefMap::ROOT);
-    let mut worklist = vec![(root, empty)];
+    let mut worklist = vec![(root, 0)];
-    while let Some((module, mod_path)) = worklist.pop() {
+    // Records items' minimum module depth.
+    let mut depth_map = FxHashMap::default();
+
+    while let Some((module, depth)) = worklist.pop() {
         let ext_def_map;
         let mod_data = if module.krate == krate {
             &def_map[module.local_id]
@@ -201,52 +109,83 @@ fn collect_import_map(db: &dyn DefDatabase, krate: CrateId) -> ImportMap {
         });
 
         for (name, per_ns) in visible_items {
-            let mk_path = || {
-                let mut path = mod_path.clone();
-                path.segments.push(name.clone());
-                path
-            };
-
             for item in per_ns.iter_items() {
-                let path = mk_path();
+                let import_info = ImportInfo {
-                let path_len = path.len();
+                    name: name.clone(),
-                let import_info =
+                    container: module,
-                    ImportInfo { path, container: module, is_trait_assoc_item: false };
+                    is_trait_assoc_item: false,
+                };
 
-                if let Some(ModuleDefId::TraitId(tr)) = item.as_module_def_id() {
+                match depth_map.entry(item) {
-                    import_map.collect_trait_assoc_items(
-                        db,
-                        tr,
-                        matches!(item, ItemInNs::Types(_)),
-                        &import_info,
-                    );
-                }
-
-                match import_map.map.entry(item) {
                     Entry::Vacant(entry) => {
-                        entry.insert(import_info);
+                        entry.insert(depth);
                     }
                     Entry::Occupied(mut entry) => {
-                        // If the new path is shorter, prefer that one.
+                        if depth < *entry.get() {
-                        if path_len < entry.get().path.len() {
+                            entry.insert(depth);
-                            *entry.get_mut() = import_info;
                         } else {
                             continue;
                         }
                     }
                 }
 
-                // If we've just added a path to a module, descend into it. We might traverse
+                if let Some(ModuleDefId::TraitId(tr)) = item.as_module_def_id() {
-                // modules multiple times, but only if the new path to it is shorter than the
+                    collect_trait_assoc_items(
-                // first (else we `continue` above).
+                        db,
+                        &mut map,
+                        tr,
+                        matches!(item, ItemInNs::Types(_)),
+                        &import_info,
+                    );
+                }
+
+                map.insert(item, import_info);
+
+                // If we've just added a module, descend into it. We might traverse modules
+                // multiple times, but only if the module depth is smaller (else we `continue`
+                // above).
                 if let Some(ModuleDefId::ModuleId(mod_id)) = item.as_module_def_id() {
-                    worklist.push((mod_id, mk_path()));
+                    worklist.push((mod_id, depth + 1));
                 }
             }
         }
     }
 
-    import_map
+    map
+}
+
+fn collect_trait_assoc_items(
+    db: &dyn DefDatabase,
+    map: &mut FxIndexMap<ItemInNs, ImportInfo>,
+    tr: TraitId,
+    is_type_in_ns: bool,
+    trait_import_info: &ImportInfo,
+) {
+    let _p = profile::span("collect_trait_assoc_items");
+    for (assoc_item_name, item) in &db.trait_data(tr).items {
+        let module_def_id = match item {
+            AssocItemId::FunctionId(f) => ModuleDefId::from(*f),
+            AssocItemId::ConstId(c) => ModuleDefId::from(*c),
+            // cannot use associated type aliases directly: need a `<Struct as Trait>::TypeAlias`
+            // qualifier, ergo no need to store it for imports in import_map
+            AssocItemId::TypeAliasId(_) => {
+                cov_mark::hit!(type_aliases_ignored);
+                continue;
+            }
+        };
+        let assoc_item = if is_type_in_ns {
+            ItemInNs::Types(module_def_id)
+        } else {
+            ItemInNs::Values(module_def_id)
+        };
+
+        let assoc_item_info = ImportInfo {
+            container: trait_import_info.container,
+            name: assoc_item_name.clone(),
+            is_trait_assoc_item: true,
+        };
+        map.insert(assoc_item, assoc_item_info);
+    }
 }
 
 impl PartialEq for ImportMap {
@@ -260,7 +199,7 @@ impl Eq for ImportMap {}
 
 impl fmt::Debug for ImportMap {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        let mut importable_paths: Vec<_> = self
+        let mut importable_names: Vec<_> = self
             .map
             .iter()
             .map(|(item, _)| match item {
@@ -270,56 +209,40 @@ impl fmt::Debug for ImportMap {
             })
             .collect();
 
-        importable_paths.sort();
+        importable_names.sort();
-        f.write_str(&importable_paths.join("\n"))
+        f.write_str(&importable_names.join("\n"))
     }
 }
 
-fn fst_path(db: &dyn DefDatabase, path: &ImportPath) -> String {
-    let _p = profile::span("fst_path");
-    let mut s = path.display(db).to_string();
-    s.make_ascii_lowercase();
-    s
-}
-
-#[derive(Debug, Eq, PartialEq, Hash)]
-pub enum ImportKind {
-    Module,
-    Function,
-    Adt,
-    EnumVariant,
-    Const,
-    Static,
-    Trait,
-    TraitAlias,
-    TypeAlias,
-    BuiltinType,
-    AssociatedItem,
-    Macro,
-}
-
 /// A way to match import map contents against the search query.
 #[derive(Debug)]
-pub enum SearchMode {
+enum SearchMode {
     /// Import map entry should strictly match the query string.
-    Equals,
+    Exact,
-    /// Import map entry should contain the query string.
-    Contains,
     /// Import map entry should contain all letters from the query string,
     /// in the same order, but not necessary adjacent.
     Fuzzy,
 }
 
+/// Three possible ways to search for the name in associated and/or other items.
+#[derive(Debug, Clone, Copy)]
+pub enum AssocSearchMode {
+    /// Search for the name in both associated and other items.
+    Include,
+    /// Search for the name in other items only.
+    Exclude,
+    /// Search for the name in the associated items only.
+    AssocItemsOnly,
+}
+
 #[derive(Debug)]
 pub struct Query {
     query: String,
     lowercased: String,
-    name_only: bool,
-    assoc_items_only: bool,
     search_mode: SearchMode,
+    assoc_mode: AssocSearchMode,
     case_sensitive: bool,
     limit: usize,
-    exclude_import_kinds: FxHashSet<ImportKind>,
 }
 
 impl Query {
@@ -328,30 +251,21 @@ impl Query {
         Self {
             query,
             lowercased,
-            name_only: false,
+            search_mode: SearchMode::Exact,
-            assoc_items_only: false,
+            assoc_mode: AssocSearchMode::Include,
-            search_mode: SearchMode::Contains,
             case_sensitive: false,
-            limit: usize::max_value(),
+            limit: usize::MAX,
-            exclude_import_kinds: FxHashSet::default(),
         }
     }
 
-    /// Matches entries' names only, ignoring the rest of
+    /// Fuzzy finds items instead of exact matching.
-    /// the qualifier.
+    pub fn fuzzy(self) -> Self {
-    /// Example: for `std::marker::PhantomData`, the name is `PhantomData`.
+        Self { search_mode: SearchMode::Fuzzy, ..self }
-    pub fn name_only(self) -> Self {
-        Self { name_only: true, ..self }
     }
 
-    /// Matches only the entries that are associated items, ignoring the rest.
+    /// Specifies whether we want to include associated items in the result.
-    pub fn assoc_items_only(self) -> Self {
+    pub fn assoc_search_mode(self, assoc_mode: AssocSearchMode) -> Self {
-        Self { assoc_items_only: true, ..self }
+        Self { assoc_mode, ..self }
-    }
-
-    /// Specifies the way to search for the entries using the query.
-    pub fn search_mode(self, search_mode: SearchMode) -> Self {
-        Self { search_mode, ..self }
     }
 
     /// Limits the returned number of items to `limit`.
@@ -364,12 +278,6 @@ impl Query {
         Self { case_sensitive: true, ..self }
     }
 
-    /// Do not include imports of the specified kind in the search results.
-    pub fn exclude_import_kind(mut self, import_kind: ImportKind) -> Self {
-        self.exclude_import_kinds.insert(import_kind);
-        self
-    }
-
     fn import_matches(
         &self,
         db: &dyn DefDatabase,
@@ -377,49 +285,36 @@ impl Query {
         enforce_lowercase: bool,
     ) -> bool {
         let _p = profile::span("import_map::Query::import_matches");
-        if import.is_trait_assoc_item {
+        match (import.is_trait_assoc_item, self.assoc_mode) {
-            if self.exclude_import_kinds.contains(&ImportKind::AssociatedItem) {
+            (true, AssocSearchMode::Exclude) => return false,
-                return false;
+            (false, AssocSearchMode::AssocItemsOnly) => return false,
-            }
+            _ => {}
-        } else if self.assoc_items_only {
-            return false;
         }
 
-        let mut input = if import.is_trait_assoc_item || self.name_only {
+        let mut input = import.name.display(db.upcast()).to_string();
-            import.path.segments.last().unwrap().display(db.upcast()).to_string()
+        let case_insensitive = enforce_lowercase || !self.case_sensitive;
-        } else {
+        if case_insensitive {
-            import.path.display(db).to_string()
-        };
-        if enforce_lowercase || !self.case_sensitive {
             input.make_ascii_lowercase();
         }
 
-        let query_string =
+        let query_string = if case_insensitive { &self.lowercased } else { &self.query };
-            if !enforce_lowercase && self.case_sensitive { &self.query } else { &self.lowercased };
 
         match self.search_mode {
-            SearchMode::Equals => &input == query_string,
+            SearchMode::Exact => &input == query_string,
-            SearchMode::Contains => input.contains(query_string),
             SearchMode::Fuzzy => {
-                let mut unchecked_query_chars = query_string.chars();
+                let mut input_chars = input.chars();
-                let mut mismatching_query_char = unchecked_query_chars.next();
+                for query_char in query_string.chars() {
-
+                    if input_chars.find(|&it| it == query_char).is_none() {
-                for input_char in input.chars() {
+                        return false;
-                    match mismatching_query_char {
-                        None => return true,
-                        Some(matching_query_char) if matching_query_char == input_char => {
-                            mismatching_query_char = unchecked_query_chars.next();
-                        }
-                        _ => (),
                     }
                 }
-                mismatching_query_char.is_none()
+                true
             }
         }
     }
 }
 
-/// Searches dependencies of `krate` for an importable path matching `query`.
+/// Searches dependencies of `krate` for an importable name matching `query`.
 ///
 /// This returns a list of items that could be imported from dependencies of `krate`.
 pub fn search_dependencies(
@@ -442,65 +337,44 @@ pub fn search_dependencies(
 
     let mut stream = op.union();
 
-    let mut all_indexed_values = FxHashSet::default();
-    while let Some((_, indexed_values)) = stream.next() {
-        all_indexed_values.extend(indexed_values.iter().copied());
-    }
-
     let mut res = FxHashSet::default();
-    for indexed_value in all_indexed_values {
+    while let Some((_, indexed_values)) = stream.next() {
-        let import_map = &import_maps[indexed_value.index];
+        for indexed_value in indexed_values {
-        let importables = &import_map.importables[indexed_value.value as usize..];
+            let import_map = &import_maps[indexed_value.index];
+            let importables = &import_map.importables[indexed_value.value as usize..];
 
-        let common_importable_data = &import_map.map[&importables[0]];
+            let common_importable_data = &import_map.map[&importables[0]];
-        if !query.import_matches(db, common_importable_data, true) {
+            if !query.import_matches(db, common_importable_data, true) {
-            continue;
+                continue;
-        }
+            }
 
-        // Path shared by the importable items in this group.
+            // Name shared by the importable items in this group.
-        let common_importables_path_fst = fst_path(db, &common_importable_data.path);
+            let common_importable_name =
-        // Add the items from this `ModPath` group. Those are all subsequent items in
+                common_importable_data.name.to_smol_str().to_ascii_lowercase();
-        // `importables` whose paths match `path`.
+            // Add the items from this name group. Those are all subsequent items in
-        let iter = importables
+            // `importables` whose name match `common_importable_name`.
-            .iter()
+            let iter = importables
-            .copied()
+                .iter()
-            .take_while(|item| {
+                .copied()
-                common_importables_path_fst == fst_path(db, &import_map.map[item].path)
+                .take_while(|item| {
-            })
+                    common_importable_name
-            .filter(|&item| match item_import_kind(item) {
+                        == import_map.map[item].name.to_smol_str().to_ascii_lowercase()
-                Some(import_kind) => !query.exclude_import_kinds.contains(&import_kind),
+                })
-                None => true,
+                .filter(|item| {
-            })
+                    !query.case_sensitive // we've already checked the common importables name case-insensitively
-            .filter(|item| {
-                !query.case_sensitive // we've already checked the common importables path case-insensitively
                         || query.import_matches(db, &import_map.map[item], false)
-            });
+                });
-        res.extend(iter);
+            res.extend(iter);
 
-        if res.len() >= query.limit {
+            if res.len() >= query.limit {
-            return res;
+                return res;
+            }
         }
     }
 
     res
 }
 
-fn item_import_kind(item: ItemInNs) -> Option<ImportKind> {
-    Some(match item.as_module_def_id()? {
-        ModuleDefId::ModuleId(_) => ImportKind::Module,
-        ModuleDefId::FunctionId(_) => ImportKind::Function,
-        ModuleDefId::AdtId(_) => ImportKind::Adt,
-        ModuleDefId::EnumVariantId(_) => ImportKind::EnumVariant,
-        ModuleDefId::ConstId(_) => ImportKind::Const,
-        ModuleDefId::StaticId(_) => ImportKind::Static,
-        ModuleDefId::TraitId(_) => ImportKind::Trait,
-        ModuleDefId::TraitAliasId(_) => ImportKind::TraitAlias,
-        ModuleDefId::TypeAliasId(_) => ImportKind::TypeAlias,
-        ModuleDefId::BuiltinType(_) => ImportKind::BuiltinType,
-        ModuleDefId::MacroId(_) => ImportKind::Macro,
-    })
-}
-
 #[cfg(test)]
 mod tests {
     use base_db::{fixture::WithFixture, SourceDatabase, Upcast};
@@ -510,16 +384,39 @@ mod tests {
 
     use super::*;
 
+    impl ImportMap {
+        fn fmt_for_test(&self, db: &dyn DefDatabase) -> String {
+            let mut importable_paths: Vec<_> = self
+                .map
+                .iter()
+                .map(|(item, info)| {
+                    let path = render_path(db, info);
+                    let ns = match item {
+                        ItemInNs::Types(_) => "t",
+                        ItemInNs::Values(_) => "v",
+                        ItemInNs::Macros(_) => "m",
+                    };
+                    format!("- {path} ({ns})")
+                })
+                .collect();
+
+            importable_paths.sort();
+            importable_paths.join("\n")
+        }
+    }
+
     fn check_search(ra_fixture: &str, crate_name: &str, query: Query, expect: Expect) {
         let db = TestDB::with_files(ra_fixture);
         let crate_graph = db.crate_graph();
         let krate = crate_graph
             .iter()
-            .find(|krate| {
+            .find(|&krate| {
-                crate_graph[*krate].display_name.as_ref().map(|n| n.to_string())
+                crate_graph[krate]
-                    == Some(crate_name.to_string())
+                    .display_name
+                    .as_ref()
+                    .is_some_and(|it| &**it.crate_name() == crate_name)
             })
-            .unwrap();
+            .expect("could not find crate");
 
         let actual = search_dependencies(db.upcast(), krate, query)
             .into_iter()
@@ -530,7 +427,7 @@ mod tests {
                 let (path, mark) = match assoc_item_path(&db, &dependency_imports, dependency) {
                     Some(assoc_item_path) => (assoc_item_path, "a"),
                     None => (
-                        dependency_imports.path_of(dependency)?.display(&db).to_string(),
+                        render_path(&db, dependency_imports.import_info_for(dependency)?),
                         match dependency {
                             ItemInNs::Types(ModuleDefId::FunctionId(_))
                             | ItemInNs::Values(ModuleDefId::FunctionId(_)) => "f",
@@ -560,57 +457,25 @@ mod tests {
         dependency_imports: &ImportMap,
         dependency: ItemInNs,
     ) -> Option<String> {
-        let dependency_assoc_item_id = match dependency {
+        let (dependency_assoc_item_id, container) = match dependency.as_module_def_id()? {
-            ItemInNs::Types(ModuleDefId::FunctionId(id))
+            ModuleDefId::FunctionId(id) => (AssocItemId::from(id), id.lookup(db).container),
-            | ItemInNs::Values(ModuleDefId::FunctionId(id)) => AssocItemId::from(id),
+            ModuleDefId::ConstId(id) => (AssocItemId::from(id), id.lookup(db).container),
-            ItemInNs::Types(ModuleDefId::ConstId(id))
+            ModuleDefId::TypeAliasId(id) => (AssocItemId::from(id), id.lookup(db).container),
-            | ItemInNs::Values(ModuleDefId::ConstId(id)) => AssocItemId::from(id),
-            ItemInNs::Types(ModuleDefId::TypeAliasId(id))
-            | ItemInNs::Values(ModuleDefId::TypeAliasId(id)) => AssocItemId::from(id),
             _ => return None,
         };
 
-        let trait_ = assoc_to_trait(db, dependency)?;
+        let ItemContainerId::TraitId(trait_id) = container else {
-        if let ModuleDefId::TraitId(tr) = trait_.as_module_def_id()? {
+            return None;
-            let trait_data = db.trait_data(tr);
-            let assoc_item_name =
-                trait_data.items.iter().find_map(|(assoc_item_name, assoc_item_id)| {
-                    if &dependency_assoc_item_id == assoc_item_id {
-                        Some(assoc_item_name)
-                    } else {
-                        None
-                    }
-                })?;
-            return Some(format!(
-                "{}::{}",
-                dependency_imports.path_of(trait_)?.display(db),
-                assoc_item_name.display(db.upcast())
-            ));
-        }
-        None
-    }
-
-    fn assoc_to_trait(db: &dyn DefDatabase, item: ItemInNs) -> Option<ItemInNs> {
-        let assoc: AssocItemId = match item {
-            ItemInNs::Types(it) | ItemInNs::Values(it) => match it {
-                ModuleDefId::TypeAliasId(it) => it.into(),
-                ModuleDefId::FunctionId(it) => it.into(),
-                ModuleDefId::ConstId(it) => it.into(),
-                _ => return None,
-            },
-            _ => return None,
         };
 
-        let container = match assoc {
+        let trait_info = dependency_imports.import_info_for(ItemInNs::Types(trait_id.into()))?;
-            AssocItemId::FunctionId(it) => it.lookup(db).container,
-            AssocItemId::ConstId(it) => it.lookup(db).container,
-            AssocItemId::TypeAliasId(it) => it.lookup(db).container,
-        };
 
-        match container {
+        let trait_data = db.trait_data(trait_id);
-            ItemContainerId::TraitId(it) => Some(ItemInNs::Types(it.into())),
+        let (assoc_item_name, _) = trait_data
-            _ => None,
+            .items
-        }
+            .iter()
+            .find(|(_, assoc_item_id)| &dependency_assoc_item_id == assoc_item_id)?;
+        Some(format!("{}::{}", render_path(db, trait_info), assoc_item_name.display(db.upcast())))
     }
 
     fn check(ra_fixture: &str, expect: Expect) {
@@ -633,6 +498,24 @@ mod tests {
         expect.assert_eq(&actual)
     }
 
+    fn render_path(db: &dyn DefDatabase, info: &ImportInfo) -> String {
+        let mut module = info.container;
+        let mut segments = vec![&info.name];
+
+        let def_map = module.def_map(db);
+        assert!(def_map.block_id().is_none(), "block local items should not be in `ImportMap`");
+
+        while let Some(parent) = module.containing_module(db) {
+            let parent_data = &def_map[parent.local_id];
+            let (name, _) =
+                parent_data.children.iter().find(|(_, id)| **id == module.local_id).unwrap();
+            segments.push(name);
+            module = parent;
+        }
+
+        segments.iter().rev().map(|it| it.display(db.upcast())).join("::")
+    }
+
     #[test]
     fn smoke() {
         check(
@@ -749,6 +632,7 @@ mod tests {
     #[test]
     fn module_reexport() {
         // Reexporting modules from a dependency adds all contents to the import map.
+        // XXX: The rendered paths are relative to the defining crate.
         check(
             r"
             //- /main.rs crate:main deps:lib
@@ -764,9 +648,9 @@ mod tests {
                 - module::S (t)
                 - module::S (v)
                 main:
+                - module::S (t)
+                - module::S (v)
                 - reexported_module (t)
-                - reexported_module::S (t)
-                - reexported_module::S (v)
             "#]],
         );
     }
@@ -868,10 +752,9 @@ mod tests {
         check_search(
             ra_fixture,
             "main",
-            Query::new("fmt".to_string()).search_mode(SearchMode::Fuzzy),
+            Query::new("fmt".to_string()).fuzzy(),
             expect![[r#"
                 dep::fmt (t)
-                dep::fmt::Display (t)
                 dep::fmt::Display::FMT_CONST (a)
                 dep::fmt::Display::format_function (a)
                 dep::fmt::Display::format_method (a)
@@ -898,7 +781,9 @@ mod tests {
         check_search(
             ra_fixture,
             "main",
-            Query::new("fmt".to_string()).search_mode(SearchMode::Fuzzy).assoc_items_only(),
+            Query::new("fmt".to_string())
+                .fuzzy()
+                .assoc_search_mode(AssocSearchMode::AssocItemsOnly),
             expect![[r#"
                 dep::fmt::Display::FMT_CONST (a)
                 dep::fmt::Display::format_function (a)
@@ -909,23 +794,10 @@ mod tests {
         check_search(
             ra_fixture,
             "main",
-            Query::new("fmt".to_string())
+            Query::new("fmt".to_string()).fuzzy().assoc_search_mode(AssocSearchMode::Exclude),
-                .search_mode(SearchMode::Fuzzy)
-                .exclude_import_kind(ImportKind::AssociatedItem),
             expect![[r#"
-            dep::fmt (t)
+                dep::fmt (t)
-            dep::fmt::Display (t)
+            "#]],
-        "#]],
-        );
-
-        check_search(
-            ra_fixture,
-            "main",
-            Query::new("fmt".to_string())
-                .search_mode(SearchMode::Fuzzy)
-                .assoc_items_only()
-                .exclude_import_kind(ImportKind::AssociatedItem),
-            expect![[r#""#]],
         );
     }
 
@@ -958,13 +830,12 @@ mod tests {
         check_search(
             ra_fixture,
             "main",
-            Query::new("fmt".to_string()).search_mode(SearchMode::Fuzzy),
+            Query::new("fmt".to_string()).fuzzy(),
             expect![[r#"
                 dep::Fmt (m)
                 dep::Fmt (t)
                 dep::Fmt (v)
                 dep::fmt (t)
-                dep::fmt::Display (t)
                 dep::fmt::Display::fmt (a)
                 dep::format (f)
             "#]],
@@ -973,7 +844,7 @@ mod tests {
         check_search(
             ra_fixture,
             "main",
-            Query::new("fmt".to_string()).search_mode(SearchMode::Equals),
+            Query::new("fmt".to_string()),
             expect![[r#"
                 dep::Fmt (m)
                 dep::Fmt (t)
@@ -982,20 +853,6 @@ mod tests {
                 dep::fmt::Display::fmt (a)
             "#]],
         );
-
-        check_search(
-            ra_fixture,
-            "main",
-            Query::new("fmt".to_string()).search_mode(SearchMode::Contains),
-            expect![[r#"
-                dep::Fmt (m)
-                dep::Fmt (t)
-                dep::Fmt (v)
-                dep::fmt (t)
-                dep::fmt::Display (t)
-                dep::fmt::Display::fmt (a)
-            "#]],
-        );
     }
 
     #[test]
@@ -1033,7 +890,6 @@ mod tests {
                 dep::Fmt (t)
                 dep::Fmt (v)
                 dep::fmt (t)
-                dep::fmt::Display (t)
                 dep::fmt::Display::fmt (a)
             "#]],
         );
@@ -1041,7 +897,7 @@ mod tests {
         check_search(
             ra_fixture,
             "main",
-            Query::new("fmt".to_string()).name_only(),
+            Query::new("fmt".to_string()),
             expect![[r#"
                 dep::Fmt (m)
                 dep::Fmt (t)
@@ -1106,43 +962,10 @@ mod tests {
         pub fn no() {}
     "#,
             "main",
-            Query::new("".to_string()).limit(2),
+            Query::new("".to_string()).fuzzy().limit(1),
             expect![[r#"
-                dep::Fmt (m)
+                dep::fmt::Display (t)
-                dep::Fmt (t)
-                dep::Fmt (v)
-                dep::fmt (t)
             "#]],
         );
     }
-
-    #[test]
-    fn search_exclusions() {
-        let ra_fixture = r#"
-            //- /main.rs crate:main deps:dep
-            //- /dep.rs crate:dep
-
-            pub struct fmt;
-            pub struct FMT;
-        "#;
-
-        check_search(
-            ra_fixture,
-            "main",
-            Query::new("FMT".to_string()),
-            expect![[r#"
-                dep::FMT (t)
-                dep::FMT (v)
-                dep::fmt (t)
-                dep::fmt (v)
-            "#]],
-        );
-
-        check_search(
-            ra_fixture,
-            "main",
-            Query::new("FMT".to_string()).exclude_import_kind(ImportKind::Adt),
-            expect![[r#""#]],
-        );
-    }
 }

crates/hir-def/src/item_scope.rs

@@ -14,8 +14,8 @@ use stdx::format_to;
 use syntax::ast;
 
 use crate::{
-    db::DefDatabase, per_ns::PerNs, visibility::Visibility, AdtId, BuiltinType, ConstId, HasModule,
+    db::DefDatabase, per_ns::PerNs, visibility::Visibility, AdtId, BuiltinType, ConstId,
-    ImplId, LocalModuleId, MacroId, ModuleDefId, ModuleId, TraitId,
+    ExternCrateId, HasModule, ImplId, LocalModuleId, MacroId, ModuleDefId, ModuleId, TraitId,
 };
 
 #[derive(Copy, Clone, Debug)]
@@ -50,6 +50,7 @@ pub struct ItemScope {
     unnamed_consts: Vec<ConstId>,
     /// Traits imported via `use Trait as _;`.
     unnamed_trait_imports: FxHashMap<TraitId, Visibility>,
+    extern_crate_decls: Vec<ExternCrateId>,
     /// Macros visible in current module in legacy textual scope
     ///
     /// For macros invoked by an unqualified identifier like `bar!()`, `legacy_macros` will be searched in first.
@@ -188,7 +189,11 @@ impl ItemScope {
     }
 
     pub(crate) fn define_impl(&mut self, imp: ImplId) {
-        self.impls.push(imp)
+        self.impls.push(imp);
+    }
+
+    pub(crate) fn define_extern_crate_decl(&mut self, extern_crate: ExternCrateId) {
+        self.extern_crate_decls.push(extern_crate);
     }
 
     pub(crate) fn define_unnamed_const(&mut self, konst: ConstId) {
@@ -397,6 +402,7 @@ impl ItemScope {
             legacy_macros,
             attr_macros,
             derive_macros,
+            extern_crate_decls,
         } = self;
         types.shrink_to_fit();
         values.shrink_to_fit();
@@ -409,6 +415,7 @@ impl ItemScope {
         legacy_macros.shrink_to_fit();
         attr_macros.shrink_to_fit();
         derive_macros.shrink_to_fit();
+        extern_crate_decls.shrink_to_fit();
     }
 }
 

crates/hir-def/src/item_tree.rs

@@ -46,7 +46,7 @@ use ast::{AstNode, HasName, StructKind};
 use base_db::CrateId;
 use either::Either;
 use hir_expand::{
-    ast_id_map::FileAstId,
+    ast_id_map::{AstIdNode, FileAstId},
     attrs::RawAttrs,
     hygiene::Hygiene,
     name::{name, AsName, Name},
@@ -314,7 +314,7 @@ from_attrs!(ModItem(ModItem), Variant(Idx<Variant>), Field(Idx<Field>), Param(Id
 
 /// Trait implemented by all item nodes in the item tree.
 pub trait ItemTreeNode: Clone {
-    type Source: AstNode + Into<ast::Item>;
+    type Source: AstIdNode + Into<ast::Item>;
 
     fn ast_id(&self) -> FileAstId<Self::Source>;
 

crates/hir-def/src/item_tree/pretty.rs

@@ -52,7 +52,7 @@ struct Printer<'a> {
     needs_indent: bool,
 }
 
-impl<'a> Printer<'a> {
+impl Printer<'_> {
     fn indented(&mut self, f: impl FnOnce(&mut Self)) {
         self.indent_level += 1;
         wln!(self);
@@ -572,7 +572,7 @@ impl<'a> Printer<'a> {
     }
 }
 
-impl<'a> Write for Printer<'a> {
+impl Write for Printer<'_> {
     fn write_str(&mut self, s: &str) -> fmt::Result {
         for line in s.split_inclusive('\n') {
             if self.needs_indent {

crates/hir-def/src/lang_item.rs

@@ -180,15 +180,15 @@ impl LangItems {
         T: Into<AttrDefId> + Copy,
     {
         let _p = profile::span("collect_lang_item");
-        if let Some(lang_item) = lang_attr(db, item) {
+        if let Some(lang_item) = db.lang_attr(item.into()) {
             self.items.entry(lang_item).or_insert_with(|| constructor(item));
         }
     }
 }
 
-pub fn lang_attr(db: &dyn DefDatabase, item: impl Into<AttrDefId> + Copy) -> Option<LangItem> {
+pub(crate) fn lang_attr_query(db: &dyn DefDatabase, item: AttrDefId) -> Option<LangItem> {
-    let attrs = db.attrs(item.into());
+    let attrs = db.attrs(item);
-    attrs.by_key("lang").string_value().cloned().and_then(|it| LangItem::from_str(&it))
+    attrs.by_key("lang").string_value().and_then(|it| LangItem::from_str(&it))
 }
 
 pub enum GenericRequirement {

crates/hir-def/src/lib.rs

@@ -64,7 +64,7 @@ use std::{
 
 use base_db::{impl_intern_key, salsa, CrateId, ProcMacroKind};
 use hir_expand::{
-    ast_id_map::FileAstId,
+    ast_id_map::{AstIdNode, FileAstId},
     attrs::{Attr, AttrId, AttrInput},
     builtin_attr_macro::BuiltinAttrExpander,
     builtin_derive_macro::BuiltinDeriveExpander,
@@ -88,8 +88,8 @@ use crate::{
     builtin_type::BuiltinType,
     data::adt::VariantData,
     item_tree::{
-        Const, Enum, Function, Impl, ItemTreeId, ItemTreeNode, MacroDef, MacroRules, Static,
+        Const, Enum, ExternCrate, Function, Impl, Import, ItemTreeId, ItemTreeNode, MacroDef,
-        Struct, Trait, TraitAlias, TypeAlias, Union,
+        MacroRules, Static, Struct, Trait, TraitAlias, TypeAlias, Union,
     },
 };
 
@@ -145,24 +145,28 @@ pub struct ModuleId {
 }
 
 impl ModuleId {
-    pub fn def_map(&self, db: &dyn db::DefDatabase) -> Arc<DefMap> {
+    pub fn def_map(self, db: &dyn db::DefDatabase) -> Arc<DefMap> {
         match self.block {
             Some(block) => db.block_def_map(block),
             None => db.crate_def_map(self.krate),
         }
     }
 
-    pub fn krate(&self) -> CrateId {
+    pub fn krate(self) -> CrateId {
         self.krate
     }
 
-    pub fn containing_module(&self, db: &dyn db::DefDatabase) -> Option<ModuleId> {
+    pub fn containing_module(self, db: &dyn db::DefDatabase) -> Option<ModuleId> {
         self.def_map(db).containing_module(self.local_id)
     }
 
-    pub fn containing_block(&self) -> Option<BlockId> {
+    pub fn containing_block(self) -> Option<BlockId> {
         self.block
     }
+
+    pub fn is_block_module(self) -> bool {
+        self.block.is_some() && self.local_id == DefMap::ROOT
+    }
 }
 
 /// An ID of a module, **local** to a `DefMap`.
@@ -313,6 +317,16 @@ pub struct ImplId(salsa::InternId);
 type ImplLoc = ItemLoc<Impl>;
 impl_intern!(ImplId, ImplLoc, intern_impl, lookup_intern_impl);
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Ord, PartialOrd)]
+pub struct ImportId(salsa::InternId);
+type ImportLoc = ItemLoc<Import>;
+impl_intern!(ImportId, ImportLoc, intern_import, lookup_intern_import);
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Ord, PartialOrd)]
+pub struct ExternCrateId(salsa::InternId);
+type ExternCrateLoc = ItemLoc<ExternCrate>;
+impl_intern!(ExternCrateId, ExternCrateLoc, intern_extern_crate, lookup_intern_extern_crate);
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Ord, PartialOrd)]
 pub struct ExternBlockId(salsa::InternId);
 type ExternBlockLoc = ItemLoc<ExternBlock>;
@@ -392,14 +406,14 @@ impl TypeParamId {
 
 impl TypeParamId {
     /// Caller should check if this toc id really belongs to a type
-    pub fn from_unchecked(x: TypeOrConstParamId) -> Self {
+    pub fn from_unchecked(it: TypeOrConstParamId) -> Self {
-        Self(x)
+        Self(it)
     }
 }
 
 impl From<TypeParamId> for TypeOrConstParamId {
-    fn from(x: TypeParamId) -> Self {
+    fn from(it: TypeParamId) -> Self {
-        x.0
+        it.0
     }
 }
 
@@ -418,14 +432,14 @@ impl ConstParamId {
 
 impl ConstParamId {
     /// Caller should check if this toc id really belongs to a const
-    pub fn from_unchecked(x: TypeOrConstParamId) -> Self {
+    pub fn from_unchecked(it: TypeOrConstParamId) -> Self {
-        Self(x)
+        Self(it)
     }
 }
 
 impl From<ConstParamId> for TypeOrConstParamId {
-    fn from(x: ConstParamId) -> Self {
+    fn from(it: ConstParamId) -> Self {
-        x.0
+        it.0
     }
 }
 
@@ -548,14 +562,14 @@ pub enum TypeOwnerId {
 impl TypeOwnerId {
     fn as_generic_def_id(self) -> Option<GenericDefId> {
         Some(match self {
-            TypeOwnerId::FunctionId(x) => GenericDefId::FunctionId(x),
+            TypeOwnerId::FunctionId(it) => GenericDefId::FunctionId(it),
-            TypeOwnerId::ConstId(x) => GenericDefId::ConstId(x),
+            TypeOwnerId::ConstId(it) => GenericDefId::ConstId(it),
-            TypeOwnerId::AdtId(x) => GenericDefId::AdtId(x),
+            TypeOwnerId::AdtId(it) => GenericDefId::AdtId(it),
-            TypeOwnerId::TraitId(x) => GenericDefId::TraitId(x),
+            TypeOwnerId::TraitId(it) => GenericDefId::TraitId(it),
-            TypeOwnerId::TraitAliasId(x) => GenericDefId::TraitAliasId(x),
+            TypeOwnerId::TraitAliasId(it) => GenericDefId::TraitAliasId(it),
-            TypeOwnerId::TypeAliasId(x) => GenericDefId::TypeAliasId(x),
+            TypeOwnerId::TypeAliasId(it) => GenericDefId::TypeAliasId(it),
-            TypeOwnerId::ImplId(x) => GenericDefId::ImplId(x),
+            TypeOwnerId::ImplId(it) => GenericDefId::ImplId(it),
-            TypeOwnerId::EnumVariantId(x) => GenericDefId::EnumVariantId(x),
+            TypeOwnerId::EnumVariantId(it) => GenericDefId::EnumVariantId(it),
             TypeOwnerId::InTypeConstId(_) | TypeOwnerId::ModuleId(_) | TypeOwnerId::StaticId(_) => {
                 return None
             }
@@ -578,15 +592,15 @@ impl_from!(
     for TypeOwnerId
 );
 
-// Every `DefWithBodyId` is a type owner, since bodies can contain type (e.g. `{ let x: Type = _; }`)
+// Every `DefWithBodyId` is a type owner, since bodies can contain type (e.g. `{ let it: Type = _; }`)
 impl From<DefWithBodyId> for TypeOwnerId {
     fn from(value: DefWithBodyId) -> Self {
         match value {
-            DefWithBodyId::FunctionId(x) => x.into(),
+            DefWithBodyId::FunctionId(it) => it.into(),
-            DefWithBodyId::StaticId(x) => x.into(),
+            DefWithBodyId::StaticId(it) => it.into(),
-            DefWithBodyId::ConstId(x) => x.into(),
+            DefWithBodyId::ConstId(it) => it.into(),
-            DefWithBodyId::InTypeConstId(x) => x.into(),
+            DefWithBodyId::InTypeConstId(it) => it.into(),
-            DefWithBodyId::VariantId(x) => x.into(),
+            DefWithBodyId::VariantId(it) => it.into(),
         }
     }
 }
@@ -594,14 +608,14 @@ impl From<DefWithBodyId> for TypeOwnerId {
 impl From<GenericDefId> for TypeOwnerId {
     fn from(value: GenericDefId) -> Self {
         match value {
-            GenericDefId::FunctionId(x) => x.into(),
+            GenericDefId::FunctionId(it) => it.into(),
-            GenericDefId::AdtId(x) => x.into(),
+            GenericDefId::AdtId(it) => it.into(),
-            GenericDefId::TraitId(x) => x.into(),
+            GenericDefId::TraitId(it) => it.into(),
-            GenericDefId::TraitAliasId(x) => x.into(),
+            GenericDefId::TraitAliasId(it) => it.into(),
-            GenericDefId::TypeAliasId(x) => x.into(),
+            GenericDefId::TypeAliasId(it) => it.into(),
-            GenericDefId::ImplId(x) => x.into(),
+            GenericDefId::ImplId(it) => it.into(),
-            GenericDefId::EnumVariantId(x) => x.into(),
+            GenericDefId::EnumVariantId(it) => it.into(),
-            GenericDefId::ConstId(x) => x.into(),
+            GenericDefId::ConstId(it) => it.into(),
         }
     }
 }
@@ -716,7 +730,7 @@ impl GeneralConstId {
                 .const_data(const_id)
                 .name
                 .as_ref()
-                .and_then(|x| x.as_str())
+                .and_then(|it| it.as_str())
                 .unwrap_or("_")
                 .to_owned(),
             GeneralConstId::ConstBlockId(id) => format!("{{anonymous const {id:?}}}"),
@@ -821,6 +835,7 @@ pub enum AttrDefId {
     ImplId(ImplId),
     GenericParamId(GenericParamId),
     ExternBlockId(ExternBlockId),
+    ExternCrateId(ExternCrateId),
 }
 
 impl_from!(
@@ -835,7 +850,8 @@ impl_from!(
     TypeAliasId,
     MacroId(Macro2Id, MacroRulesId, ProcMacroId),
     ImplId,
-    GenericParamId
+    GenericParamId,
+    ExternCrateId
     for AttrDefId
 );
 
@@ -927,6 +943,12 @@ impl HasModule for AdtId {
     }
 }
 
+impl HasModule for ExternCrateId {
+    fn module(&self, db: &dyn db::DefDatabase) -> ModuleId {
+        self.lookup(db).container
+    }
+}
+
 impl HasModule for VariantId {
     fn module(&self, db: &dyn db::DefDatabase) -> ModuleId {
         match self {
@@ -950,17 +972,17 @@ impl HasModule for MacroId {
 impl HasModule for TypeOwnerId {
     fn module(&self, db: &dyn db::DefDatabase) -> ModuleId {
         match self {
-            TypeOwnerId::FunctionId(x) => x.lookup(db).module(db),
+            TypeOwnerId::FunctionId(it) => it.lookup(db).module(db),
-            TypeOwnerId::StaticId(x) => x.lookup(db).module(db),
+            TypeOwnerId::StaticId(it) => it.lookup(db).module(db),
-            TypeOwnerId::ConstId(x) => x.lookup(db).module(db),
+            TypeOwnerId::ConstId(it) => it.lookup(db).module(db),
-            TypeOwnerId::InTypeConstId(x) => x.lookup(db).owner.module(db),
+            TypeOwnerId::InTypeConstId(it) => it.lookup(db).owner.module(db),
-            TypeOwnerId::AdtId(x) => x.module(db),
+            TypeOwnerId::AdtId(it) => it.module(db),
-            TypeOwnerId::TraitId(x) => x.lookup(db).container,
+            TypeOwnerId::TraitId(it) => it.lookup(db).container,
-            TypeOwnerId::TraitAliasId(x) => x.lookup(db).container,
+            TypeOwnerId::TraitAliasId(it) => it.lookup(db).container,
-            TypeOwnerId::TypeAliasId(x) => x.lookup(db).module(db),
+            TypeOwnerId::TypeAliasId(it) => it.lookup(db).module(db),
-            TypeOwnerId::ImplId(x) => x.lookup(db).container,
+            TypeOwnerId::ImplId(it) => it.lookup(db).container,
-            TypeOwnerId::EnumVariantId(x) => x.parent.lookup(db).container,
+            TypeOwnerId::EnumVariantId(it) => it.parent.lookup(db).container,
-            TypeOwnerId::ModuleId(x) => *x,
+            TypeOwnerId::ModuleId(it) => *it,
         }
     }
 }
@@ -1050,6 +1072,7 @@ impl AttrDefId {
                 .krate
             }
             AttrDefId::MacroId(it) => it.module(db).krate,
+            AttrDefId::ExternCrateId(it) => it.lookup(db).container.krate,
         }
     }
 }
@@ -1101,12 +1124,12 @@ impl AsMacroCall for InFile<&ast::MacroCall> {
 
 /// Helper wrapper for `AstId` with `ModPath`
 #[derive(Clone, Debug, Eq, PartialEq)]
-struct AstIdWithPath<T: ast::AstNode> {
+struct AstIdWithPath<T: AstIdNode> {
     ast_id: AstId<T>,
     path: path::ModPath,
 }
 
-impl<T: ast::AstNode> AstIdWithPath<T> {
+impl<T: AstIdNode> AstIdWithPath<T> {
     fn new(file_id: HirFileId, ast_id: FileAstId<T>, path: path::ModPath) -> AstIdWithPath<T> {
         AstIdWithPath { ast_id: AstId::new(file_id, ast_id), path }
     }

crates/hir-def/src/lower.rs

@@ -1,5 +1,9 @@
 //! Context for lowering paths.
-use hir_expand::{ast_id_map::AstIdMap, hygiene::Hygiene, AstId, HirFileId, InFile};
+use hir_expand::{
+    ast_id_map::{AstIdMap, AstIdNode},
+    hygiene::Hygiene,
+    AstId, HirFileId, InFile,
+};
 use once_cell::unsync::OnceCell;
 use syntax::ast;
 use triomphe::Arc;
@@ -37,7 +41,7 @@ impl<'a> LowerCtx<'a> {
         Path::from_src(ast, self)
     }
 
-    pub(crate) fn ast_id<N: syntax::AstNode>(&self, item: &N) -> Option<AstId<N>> {
+    pub(crate) fn ast_id<N: AstIdNode>(&self, item: &N) -> Option<AstId<N>> {
         let &(file_id, ref ast_id_map) = self.ast_id_map.as_ref()?;
         let ast_id_map = ast_id_map.get_or_init(|| self.db.ast_id_map(file_id));
         Some(InFile::new(file_id, ast_id_map.ast_id(item)))

crates/hir-def/src/macro_expansion_tests/builtin_derive_macro.rs

@@ -278,6 +278,44 @@ impl < > core::cmp::Eq for Command< > where {}"#]],
     );
 }
 
+#[test]
+fn test_partial_eq_expand_with_derive_const() {
+    // FIXME: actually expand with const
+    check(
+        r#"
+//- minicore: derive, eq
+#[derive_const(PartialEq, Eq)]
+enum Command {
+    Move { x: i32, y: i32 },
+    Do(&'static str),
+    Jump,
+}
+"#,
+        expect![[r#"
+#[derive_const(PartialEq, Eq)]
+enum Command {
+    Move { x: i32, y: i32 },
+    Do(&'static str),
+    Jump,
+}
+
+impl < > core::cmp::PartialEq for Command< > where {
+    fn eq(&self , other: &Self ) -> bool {
+        match (self , other) {
+            (Command::Move {
+                x: x_self, y: y_self,
+            }
+            , Command::Move {
+                x: x_other, y: y_other,
+            }
+            )=>x_self.eq(x_other) && y_self.eq(y_other), (Command::Do(f0_self, ), Command::Do(f0_other, ))=>f0_self.eq(f0_other), (Command::Jump, Command::Jump)=>true , _unused=>false
+        }
+    }
+}
+impl < > core::cmp::Eq for Command< > where {}"#]],
+    );
+}
+
 #[test]
 fn test_partial_ord_expand() {
     check(
@@ -378,6 +416,44 @@ fn test_hash_expand() {
 //- minicore: derive, hash
 use core::hash::Hash;
 
+#[derive(Hash)]
+struct Foo {
+    x: i32,
+    y: u64,
+    z: (i32, u64),
+}
+"#,
+        expect![[r#"
+use core::hash::Hash;
+
+#[derive(Hash)]
+struct Foo {
+    x: i32,
+    y: u64,
+    z: (i32, u64),
+}
+
+impl < > core::hash::Hash for Foo< > where {
+    fn hash<H: core::hash::Hasher>(&self , ra_expand_state: &mut H) {
+        match self {
+            Foo {
+                x: x, y: y, z: z,
+            }
+            => {
+                x.hash(ra_expand_state);
+                y.hash(ra_expand_state);
+                z.hash(ra_expand_state);
+            }
+            ,
+        }
+    }
+}"#]],
+    );
+    check(
+        r#"
+//- minicore: derive, hash
+use core::hash::Hash;
+
 #[derive(Hash)]
 enum Command {
     Move { x: i32, y: i32 },

crates/hir-def/src/macro_expansion_tests/builtin_fn_macro.rs

@@ -201,7 +201,7 @@ macro_rules! format_args {
 }
 
 fn main() {
-    ::core::fmt::Arguments::new_v1(&["", " ", ], &[::core::fmt::Argument::new(&(arg1(a, b, c)), ::core::fmt::Display::fmt), ::core::fmt::Argument::new(&(arg2), ::core::fmt::Debug::fmt), ]);
+    ::core::fmt::Arguments::new_v1(&["", " ", ], &[::core::fmt::ArgumentV1::new(&(arg1(a, b, c)), ::core::fmt::Display::fmt), ::core::fmt::ArgumentV1::new(&(arg2), ::core::fmt::Debug::fmt), ]);
 }
 "##]],
     );
@@ -235,11 +235,11 @@ macro_rules! format_args {
 
 fn main() {
     /* error: no rule matches input tokens */;
-    /* error: no rule matches input tokens */;
+    /* error: expected expression */;
-    /* error: no rule matches input tokens */;
+    /* error: expected expression, expected COMMA */;
-    /* error: no rule matches input tokens */::core::fmt::Arguments::new_v1(&["", ], &[::core::fmt::Argument::new(&(), ::core::fmt::Display::fmt), ]);
+    /* error: expected expression */::core::fmt::Arguments::new_v1(&["", ], &[::core::fmt::ArgumentV1::new(&(), ::core::fmt::Display::fmt), ]);
-    /* error: no rule matches input tokens */;
+    /* error: expected expression, expected R_PAREN */;
-    ::core::fmt::Arguments::new_v1(&["", ], &[::core::fmt::Argument::new(&(5), ::core::fmt::Display::fmt), ]);
+    ::core::fmt::Arguments::new_v1(&["", ], &[::core::fmt::ArgumentV1::new(&(5), ::core::fmt::Display::fmt), ]);
 }
 "##]],
     );
@@ -267,7 +267,7 @@ macro_rules! format_args {
 }
 
 fn main() {
-    ::core::fmt::Arguments::new_v1(&["", " ", ], &[::core::fmt::Argument::new(&(a::<A, B>()), ::core::fmt::Display::fmt), ::core::fmt::Argument::new(&(b), ::core::fmt::Debug::fmt), ]);
+    ::core::fmt::Arguments::new_v1(&["", " ", ], &[::core::fmt::ArgumentV1::new(&(a::<A, B>()), ::core::fmt::Display::fmt), ::core::fmt::ArgumentV1::new(&(b), ::core::fmt::Debug::fmt), ]);
 }
 "##]],
     );
@@ -300,7 +300,7 @@ macro_rules! format_args {
 }
 
 fn main() {
-    ::core::fmt::Arguments::new_v1(&[r#""#, r#",mismatch,""#, r#"",""#, r#"""#, ], &[::core::fmt::Argument::new(&(location_csv_pat(db, &analysis, vfs, &sm, pat_id)), ::core::fmt::Display::fmt), ::core::fmt::Argument::new(&(mismatch.expected.display(db)), ::core::fmt::Display::fmt), ::core::fmt::Argument::new(&(mismatch.actual.display(db)), ::core::fmt::Display::fmt), ]);
+    ::core::fmt::Arguments::new_v1(&[r#""#, r#",mismatch,""#, r#"",""#, r#"""#, ], &[::core::fmt::ArgumentV1::new(&(location_csv_pat(db, &analysis, vfs, &sm, pat_id)), ::core::fmt::Display::fmt), ::core::fmt::ArgumentV1::new(&(mismatch.expected.display(db)), ::core::fmt::Display::fmt), ::core::fmt::ArgumentV1::new(&(mismatch.actual.display(db)), ::core::fmt::Display::fmt), ]);
 }
 "##]],
     );
@@ -334,7 +334,7 @@ macro_rules! format_args {
 }
 
 fn main() {
-    ::core::fmt::Arguments::new_v1(&["xxx", "y", "zzz", ], &[::core::fmt::Argument::new(&(2), ::core::fmt::Display::fmt), ::core::fmt::Argument::new(&(b), ::core::fmt::Debug::fmt), ]);
+    ::core::fmt::Arguments::new_v1(&["xxx", "y", "zzz", ], &[::core::fmt::ArgumentV1::new(&(2), ::core::fmt::Display::fmt), ::core::fmt::ArgumentV1::new(&(b), ::core::fmt::Debug::fmt), ]);
 }
 "##]],
     );
@@ -364,8 +364,8 @@ macro_rules! format_args {
 
 fn main() {
     let _ =
-        /* error: no rule matches input tokens *//* parse error: expected field name or number */
+        /* error: expected field name or number *//* parse error: expected field name or number */
-::core::fmt::Arguments::new_v1(&["", " ", ], &[::core::fmt::Argument::new(&(a.), ::core::fmt::Display::fmt), ::core::fmt::Argument::new(&(), ::core::fmt::Debug::fmt), ]);
+::core::fmt::Arguments::new_v1(&["", " ", ], &[::core::fmt::ArgumentV1::new(&(a.), ::core::fmt::Display::fmt), ::core::fmt::ArgumentV1::new(&(), ::core::fmt::Debug::fmt), ]);
 }
 "##]],
     );

crates/hir-def/src/macro_expansion_tests/mbe.rs

@@ -98,6 +98,42 @@ fn#19 main#20(#21)#21 {#22
 "##]],
     );
 }
+
+#[test]
+fn token_mapping_eager() {
+    check(
+        r#"
+#[rustc_builtin_macro]
+#[macro_export]
+macro_rules! format_args {}
+
+macro_rules! identity {
+    ($expr:expr) => { $expr };
+}
+
+fn main(foo: ()) {
+    format_args/*+tokenids*/!("{} {} {}", format_args!("{}", 0), foo, identity!(10), "bar")
+}
+
+"#,
+        expect![[r##"
+#[rustc_builtin_macro]
+#[macro_export]
+macro_rules! format_args {}
+
+macro_rules! identity {
+    ($expr:expr) => { $expr };
+}
+
+fn main(foo: ()) {
+    // format_args/*+tokenids*/!("{} {} {}"#1,#3 format_args!("{}", 0#10),#12 foo#13,#14 identity!(10#18),#21 "bar"#22)
+::core#4294967295::fmt#4294967295::Arguments#4294967295::new_v1#4294967295(&#4294967295[#4294967295""#4294967295,#4294967295 " "#4294967295,#4294967295 " "#4294967295,#4294967295 ]#4294967295,#4294967295 &#4294967295[::core#4294967295::fmt#4294967295::ArgumentV1#4294967295::new#4294967295(&#4294967295(::core#4294967295::fmt#4294967295::Arguments#4294967295::new_v1#4294967295(&#4294967295[#4294967295""#4294967295,#4294967295 ]#4294967295,#4294967295 &#4294967295[::core#4294967295::fmt#4294967295::ArgumentV1#4294967295::new#4294967295(&#4294967295(#42949672950#10)#4294967295,#4294967295 ::core#4294967295::fmt#4294967295::Display#4294967295::fmt#4294967295)#4294967295,#4294967295 ]#4294967295)#4294967295)#4294967295,#4294967295 ::core#4294967295::fmt#4294967295::Display#4294967295::fmt#4294967295)#4294967295,#4294967295 ::core#4294967295::fmt#4294967295::ArgumentV1#4294967295::new#4294967295(&#4294967295(#4294967295foo#13)#4294967295,#4294967295 ::core#4294967295::fmt#4294967295::Display#4294967295::fmt#4294967295)#4294967295,#4294967295 ::core#4294967295::fmt#4294967295::ArgumentV1#4294967295::new#4294967295(&#4294967295(#429496729510#18)#4294967295,#4294967295 ::core#4294967295::fmt#4294967295::Display#4294967295::fmt#4294967295)#4294967295,#4294967295 ]#4294967295)#4294967295
+}
+
+"##]],
+    );
+}
+
 #[test]
 fn float_field_access_macro_input() {
     check(

crates/hir-def/src/macro_expansion_tests/mod.rs

@@ -20,8 +20,8 @@ use ::mbe::TokenMap;
 use base_db::{fixture::WithFixture, ProcMacro, SourceDatabase};
 use expect_test::Expect;
 use hir_expand::{
-    db::{ExpandDatabase, TokenExpander},
+    db::{DeclarativeMacroExpander, ExpandDatabase},
-    AstId, InFile, MacroDefId, MacroDefKind, MacroFile,
+    AstId, InFile, MacroFile,
 };
 use stdx::format_to;
 use syntax::{
@@ -100,32 +100,29 @@ pub fn identity_when_valid(_attr: TokenStream, item: TokenStream) -> TokenStream
         let call_offset = macro_.syntax().text_range().start().into();
         let file_ast_id = db.ast_id_map(source.file_id).ast_id(&macro_);
         let ast_id = AstId::new(source.file_id, file_ast_id.upcast());
-        let kind = MacroDefKind::Declarative(ast_id);
 
-        let macro_def = db
+        let DeclarativeMacroExpander { mac, def_site_token_map } =
-            .macro_def(MacroDefId { krate, kind, local_inner: false, allow_internal_unsafe: false })
+            &*db.decl_macro_expander(krate, ast_id);
-            .unwrap();
+        assert_eq!(mac.err(), None);
-        if let TokenExpander::DeclarativeMacro { mac, def_site_token_map } = &*macro_def {
+        let tt = match &macro_ {
-            let tt = match &macro_ {
+            ast::Macro::MacroRules(mac) => mac.token_tree().unwrap(),
-                ast::Macro::MacroRules(mac) => mac.token_tree().unwrap(),
+            ast::Macro::MacroDef(_) => unimplemented!(""),
-                ast::Macro::MacroDef(_) => unimplemented!(""),
+        };
-            };
 
-            let tt_start = tt.syntax().text_range().start();
+        let tt_start = tt.syntax().text_range().start();
-            tt.syntax().descendants_with_tokens().filter_map(SyntaxElement::into_token).for_each(
+        tt.syntax().descendants_with_tokens().filter_map(SyntaxElement::into_token).for_each(
-                |token| {
+            |token| {
-                    let range = token.text_range().checked_sub(tt_start).unwrap();
+                let range = token.text_range().checked_sub(tt_start).unwrap();
-                    if let Some(id) = def_site_token_map.token_by_range(range) {
+                if let Some(id) = def_site_token_map.token_by_range(range) {
-                        let offset = (range.end() + tt_start).into();
+                    let offset = (range.end() + tt_start).into();
-                        text_edits.push((offset..offset, format!("#{}", id.0)));
+                    text_edits.push((offset..offset, format!("#{}", id.0)));
-                    }
+                }
-                },
+            },
-            );
+        );
-            text_edits.push((
+        text_edits.push((
-                call_offset..call_offset,
+            call_offset..call_offset,
-                format!("// call ids will be shifted by {:?}\n", mac.shift()),
+            format!("// call ids will be shifted by {:?}\n", mac.shift()),
-            ));
+        ));
-        }
     }
 
     for macro_call in source_file.syntax().descendants().filter_map(ast::MacroCall::cast) {
@@ -190,7 +187,7 @@ pub fn identity_when_valid(_attr: TokenStream, item: TokenStream) -> TokenStream
         let range: Range<usize> = range.into();
 
         if show_token_ids {
-            if let Some((tree, map, _)) = arg.as_deref() {
+            if let Some((tree, map, _)) = arg.value.as_deref() {
                 let tt_range = call.token_tree().unwrap().syntax().text_range();
                 let mut ranges = Vec::new();
                 extract_id_ranges(&mut ranges, map, tree);
@@ -239,7 +236,7 @@ pub fn identity_when_valid(_attr: TokenStream, item: TokenStream) -> TokenStream
 
     for impl_id in def_map[local_id].scope.impls() {
         let src = impl_id.lookup(&db).source(&db);
-        if src.file_id.is_builtin_derive(&db).is_some() {
+        if src.file_id.is_builtin_derive(&db) {
             let pp = pretty_print_macro_expansion(src.value.syntax().clone(), None);
             format_to!(expanded_text, "\n{}", pp)
         }

crates/hir-def/src/nameres.rs

@@ -60,7 +60,7 @@ mod tests;
 use std::{cmp::Ord, ops::Deref};
 
 use base_db::{CrateId, Edition, FileId, ProcMacroKind};
-use hir_expand::{name::Name, InFile, MacroCallId, MacroDefId};
+use hir_expand::{name::Name, HirFileId, InFile, MacroCallId, MacroDefId};
 use itertools::Itertools;
 use la_arena::Arena;
 use profile::Count;
@@ -196,6 +196,10 @@ impl BlockRelativeModuleId {
     fn into_module(self, krate: CrateId) -> ModuleId {
         ModuleId { krate, block: self.block, local_id: self.local_id }
     }
+
+    fn is_block_module(self) -> bool {
+        self.block.is_some() && self.local_id == DefMap::ROOT
+    }
 }
 
 impl std::ops::Index<LocalModuleId> for DefMap {
@@ -278,7 +282,9 @@ pub struct ModuleData {
     pub origin: ModuleOrigin,
     /// Declared visibility of this module.
     pub visibility: Visibility,
-    /// Always [`None`] for block modules
+    /// Parent module in the same `DefMap`.
+    ///
+    /// [`None`] for block modules because they are always its `DefMap`'s root.
     pub parent: Option<LocalModuleId>,
     pub children: FxHashMap<Name, LocalModuleId>,
     pub scope: ItemScope,
@@ -626,6 +632,17 @@ impl ModuleData {
         self.origin.definition_source(db)
     }
 
+    /// Same as [`definition_source`] but only returns the file id to prevent parsing the ASt.
+    pub fn definition_source_file_id(&self) -> HirFileId {
+        match self.origin {
+            ModuleOrigin::File { definition, .. } | ModuleOrigin::CrateRoot { definition } => {
+                definition.into()
+            }
+            ModuleOrigin::Inline { definition, .. } => definition.file_id,
+            ModuleOrigin::BlockExpr { block } => block.file_id,
+        }
+    }
+
     /// Returns a node which declares this module, either a `mod foo;` or a `mod foo {}`.
     /// `None` for the crate root or block.
     pub fn declaration_source(&self, db: &dyn DefDatabase) -> Option<InFile<ast::Module>> {

crates/hir-def/src/nameres/collector.rs

@@ -52,10 +52,10 @@ use crate::{
     tt,
     visibility::{RawVisibility, Visibility},
     AdtId, AstId, AstIdWithPath, ConstLoc, CrateRootModuleId, EnumLoc, EnumVariantId,
-    ExternBlockLoc, FunctionId, FunctionLoc, ImplLoc, Intern, ItemContainerId, LocalModuleId,
+    ExternBlockLoc, ExternCrateLoc, FunctionId, FunctionLoc, ImplLoc, ImportLoc, Intern,
-    Macro2Id, Macro2Loc, MacroExpander, MacroId, MacroRulesId, MacroRulesLoc, ModuleDefId,
+    ItemContainerId, LocalModuleId, Macro2Id, Macro2Loc, MacroExpander, MacroId, MacroRulesId,
-    ModuleId, ProcMacroId, ProcMacroLoc, StaticLoc, StructLoc, TraitAliasLoc, TraitLoc,
+    MacroRulesLoc, ModuleDefId, ModuleId, ProcMacroId, ProcMacroLoc, StaticLoc, StructLoc,
-    TypeAliasLoc, UnionLoc, UnresolvedMacro,
+    TraitAliasLoc, TraitLoc, TypeAliasLoc, UnionLoc, UnresolvedMacro,
 };
 
 static GLOB_RECURSION_LIMIT: Limit = Limit::new(100);
@@ -156,10 +156,9 @@ struct Import {
     alias: Option<ImportAlias>,
     visibility: RawVisibility,
     kind: ImportKind,
-    is_prelude: bool,
-    is_extern_crate: bool,
-    is_macro_use: bool,
     source: ImportSource,
+    is_prelude: bool,
+    is_macro_use: bool,
 }
 
 impl Import {
@@ -168,26 +167,23 @@ impl Import {
         krate: CrateId,
         tree: &ItemTree,
         id: ItemTreeId<item_tree::Import>,
-    ) -> Vec<Self> {
+        mut cb: impl FnMut(Self),
+    ) {
         let it = &tree[id.value];
         let attrs = &tree.attrs(db, krate, ModItem::from(id.value).into());
         let visibility = &tree[it.visibility];
         let is_prelude = attrs.by_key("prelude_import").exists();
-
-        let mut res = Vec::new();
         it.use_tree.expand(|idx, path, kind, alias| {
-            res.push(Self {
+            cb(Self {
                 path,
                 alias,
                 visibility: visibility.clone(),
                 kind,
                 is_prelude,
-                is_extern_crate: false,
                 is_macro_use: false,
                 source: ImportSource::Import { id, use_tree: idx },
             });
         });
-        res
     }
 
     fn from_extern_crate(
@@ -205,7 +201,6 @@ impl Import {
             visibility: visibility.clone(),
             kind: ImportKind::Plain,
             is_prelude: false,
-            is_extern_crate: true,
             is_macro_use: attrs.by_key("macro_use").exists(),
             source: ImportSource::ExternCrate(id),
         }
@@ -776,7 +771,7 @@ impl DefCollector<'_> {
         let _p = profile::span("resolve_import")
             .detail(|| format!("{}", import.path.display(self.db.upcast())));
         tracing::debug!("resolving import: {:?} ({:?})", import, self.def_map.data.edition);
-        if import.is_extern_crate {
+        if matches!(import.source, ImportSource::ExternCrate { .. }) {
             let name = import
                 .path
                 .as_ident()
@@ -813,11 +808,8 @@ impl DefCollector<'_> {
                 }
             }
 
-            // Check whether all namespace is resolved
+            // Check whether all namespaces are resolved.
-            if def.take_types().is_some()
+            if def.is_full() {
-                && def.take_values().is_some()
-                && def.take_macros().is_some()
-            {
                 PartialResolvedImport::Resolved(def)
             } else {
                 PartialResolvedImport::Indeterminate(def)
@@ -826,7 +818,7 @@ impl DefCollector<'_> {
     }
 
     fn resolve_extern_crate(&self, name: &Name) -> Option<CrateRootModuleId> {
-        if *name == name!(self) {
+        if *name == name![self] {
             cov_mark::hit!(extern_crate_self_as);
             Some(self.def_map.crate_root())
         } else {
@@ -867,7 +859,7 @@ impl DefCollector<'_> {
                 tracing::debug!("resolved import {:?} ({:?}) to {:?}", name, import, def);
 
                 // extern crates in the crate root are special-cased to insert entries into the extern prelude: rust-lang/rust#54658
-                if import.is_extern_crate
+                if matches!(import.source, ImportSource::ExternCrate { .. })
                     && self.def_map.block.is_none()
                     && module_id == DefMap::ROOT
                 {
@@ -1585,21 +1577,34 @@ impl ModCollector<'_, '_> {
             match item {
                 ModItem::Mod(m) => self.collect_module(m, &attrs),
                 ModItem::Import(import_id) => {
-                    let imports = Import::from_use(
+                    let _import_id = ImportLoc {
+                        container: module,
+                        id: ItemTreeId::new(self.tree_id, import_id),
+                    }
+                    .intern(db);
+                    Import::from_use(
                         db,
                         krate,
                         self.item_tree,
                         ItemTreeId::new(self.tree_id, import_id),
-                    );
+                        |import| {
-                    self.def_collector.unresolved_imports.extend(imports.into_iter().map(
+                            self.def_collector.unresolved_imports.push(ImportDirective {
-                        |import| ImportDirective {
+                                module_id: self.module_id,
-                            module_id: self.module_id,
+                                import,
-                            import,
+                                status: PartialResolvedImport::Unresolved,
-                            status: PartialResolvedImport::Unresolved,
+                            });
                         },
-                    ));
+                    )
                 }
                 ModItem::ExternCrate(import_id) => {
+                    let extern_crate_id = ExternCrateLoc {
+                        container: module,
+                        id: ItemTreeId::new(self.tree_id, import_id),
+                    }
+                    .intern(db);
+                    self.def_collector.def_map.modules[self.module_id]
+                        .scope
+                        .define_extern_crate_decl(extern_crate_id);
                     self.def_collector.unresolved_imports.push(ImportDirective {
                         module_id: self.module_id,
                         import: Import::from_extern_crate(
@@ -2230,8 +2235,12 @@ impl ModCollector<'_, '_> {
     }
 
     fn import_all_legacy_macros(&mut self, module_id: LocalModuleId) {
-        let Some((source, target)) = Self::borrow_modules(self.def_collector.def_map.modules.as_mut(), module_id, self.module_id) else {
+        let Some((source, target)) = Self::borrow_modules(
-            return
+            self.def_collector.def_map.modules.as_mut(),
+            module_id,
+            self.module_id,
+        ) else {
+            return;
         };
 
         for (name, macs) in source.scope.legacy_macros() {
@@ -2271,7 +2280,7 @@ impl ModCollector<'_, '_> {
     fn emit_unconfigured_diagnostic(&mut self, item: ModItem, cfg: &CfgExpr) {
         let ast_id = item.ast_id(self.item_tree);
 
-        let ast_id = InFile::new(self.file_id(), ast_id.upcast());
+        let ast_id = InFile::new(self.file_id(), ast_id.erase());
         self.def_collector.def_map.diagnostics.push(DefDiagnostic::unconfigured_code(
             self.module_id,
             ast_id,

crates/hir-def/src/nameres/diagnostics.rs

@@ -2,12 +2,9 @@
 
 use base_db::CrateId;
 use cfg::{CfgExpr, CfgOptions};
-use hir_expand::{attrs::AttrId, MacroCallKind};
+use hir_expand::{attrs::AttrId, ErasedAstId, MacroCallKind};
 use la_arena::Idx;
-use syntax::{
+use syntax::{ast, SyntaxError};
-    ast::{self, AnyHasAttrs},
-    SyntaxError,
-};
 
 use crate::{
     item_tree::{self, ItemTreeId},
@@ -24,7 +21,7 @@ pub enum DefDiagnosticKind {
 
     UnresolvedImport { id: ItemTreeId<item_tree::Import>, index: Idx<ast::UseTree> },
 
-    UnconfiguredCode { ast: AstId<AnyHasAttrs>, cfg: CfgExpr, opts: CfgOptions },
+    UnconfiguredCode { ast: ErasedAstId, cfg: CfgExpr, opts: CfgOptions },
 
     UnresolvedProcMacro { ast: MacroCallKind, krate: CrateId },
 
@@ -81,7 +78,7 @@ impl DefDiagnostic {
 
     pub fn unconfigured_code(
         container: LocalModuleId,
-        ast: AstId<ast::AnyHasAttrs>,
+        ast: ErasedAstId,
         cfg: CfgExpr,
         opts: CfgOptions,
     ) -> Self {

crates/hir-def/src/nameres/path_resolution.rs

@@ -12,11 +12,12 @@
 
 use base_db::Edition;
 use hir_expand::name::Name;
+use triomphe::Arc;
 
 use crate::{
     db::DefDatabase,
     item_scope::BUILTIN_SCOPE,
-    nameres::{sub_namespace_match, BuiltinShadowMode, DefMap, MacroSubNs},
+    nameres::{sub_namespace_match, BlockInfo, BuiltinShadowMode, DefMap, MacroSubNs},
     path::{ModPath, PathKind},
     per_ns::PerNs,
     visibility::{RawVisibility, Visibility},
@@ -159,13 +160,15 @@ impl DefMap {
                 (None, new) => new,
             };
 
-            match &current_map.block {
+            match current_map.block {
-                Some(block) => {
+                Some(block) if original_module == Self::ROOT => {
+                    // Block modules "inherit" names from its parent module.
                     original_module = block.parent.local_id;
                     arc = block.parent.def_map(db, current_map.krate);
-                    current_map = &*arc;
+                    current_map = &arc;
                 }
-                None => return result,
+                // Proper (non-block) modules, including those in block `DefMap`s, don't.
+                _ => return result,
             }
         }
     }
@@ -189,7 +192,7 @@ impl DefMap {
         ));
 
         let mut segments = path.segments().iter().enumerate();
-        let mut curr_per_ns: PerNs = match path.kind {
+        let mut curr_per_ns = match path.kind {
             PathKind::DollarCrate(krate) => {
                 if krate == self.krate {
                     cov_mark::hit!(macro_dollar_crate_self);
@@ -241,51 +244,54 @@ impl DefMap {
                 )
             }
             PathKind::Super(lvl) => {
-                let mut module = original_module;
+                let mut local_id = original_module;
-                for i in 0..lvl {
+                let mut ext;
-                    match self.modules[module].parent {
+                let mut def_map = self;
-                        Some(it) => module = it,
+
-                        None => match &self.block {
+                // Adjust `local_id` to `self`, i.e. the nearest non-block module.
-                            Some(block) => {
+                if def_map.module_id(local_id).is_block_module() {
-                                // Look up remaining path in parent `DefMap`
+                    (ext, local_id) = adjust_to_nearest_non_block_module(db, def_map, local_id);
-                                let new_path = ModPath::from_segments(
+                    def_map = &ext;
-                                    PathKind::Super(lvl - i),
+                }
-                                    path.segments().to_vec(),
+
-                                );
+                // Go up the module tree but skip block modules as `super` always refers to the
-                                tracing::debug!(
+                // nearest non-block module.
-                                    "`super` path: {} -> {} in parent map",
+                for _ in 0..lvl {
-                                    path.display(db.upcast()),
+                    // Loop invariant: at the beginning of each loop, `local_id` must refer to a
-                                    new_path.display(db.upcast())
+                    // non-block module.
-                                );
+                    if let Some(parent) = def_map.modules[local_id].parent {
-                                return block
+                        local_id = parent;
-                                    .parent
+                        if def_map.module_id(local_id).is_block_module() {
-                                    .def_map(db, self.krate)
+                            (ext, local_id) =
-                                    .resolve_path_fp_with_macro(
+                                adjust_to_nearest_non_block_module(db, def_map, local_id);
-                                        db,
+                            def_map = &ext;
-                                        mode,
+                        }
-                                        block.parent.local_id,
+                    } else {
-                                        &new_path,
+                        stdx::always!(def_map.block.is_none());
-                                        shadow,
+                        tracing::debug!("super path in root module");
-                                        expected_macro_subns,
+                        return ResolvePathResult::empty(ReachedFixedPoint::Yes);
-                                    );
-                            }
-                            None => {
-                                tracing::debug!("super path in root module");
-                                return ResolvePathResult::empty(ReachedFixedPoint::Yes);
-                            }
-                        },
                     }
                 }
 
-                // Resolve `self` to the containing crate-rooted module if we're a block
+                let module = def_map.module_id(local_id);
-                self.with_ancestor_maps(db, module, &mut |def_map, module| {
+                stdx::never!(module.is_block_module());
-                    if def_map.block.is_some() {
+
-                        None // keep ascending
+                if self.block != def_map.block {
-                    } else {
+                    // If we have a different `DefMap` from `self` (the orignal `DefMap` we started
-                        Some(PerNs::types(def_map.module_id(module).into(), Visibility::Public))
+                    // with), resolve the remaining path segments in that `DefMap`.
-                    }
+                    let path =
-                })
+                        ModPath::from_segments(PathKind::Super(0), path.segments().iter().cloned());
-                .expect("block DefMap not rooted in crate DefMap")
+                    return def_map.resolve_path_fp_with_macro(
+                        db,
+                        mode,
+                        local_id,
+                        &path,
+                        shadow,
+                        expected_macro_subns,
+                    );
+                }
+
+                PerNs::types(module.into(), Visibility::Public)
             }
             PathKind::Abs => {
                 // 2018-style absolute path -- only extern prelude
@@ -508,3 +514,27 @@ impl DefMap {
         }
     }
 }
+
+/// Given a block module, returns its nearest non-block module and the `DefMap` it blongs to.
+fn adjust_to_nearest_non_block_module(
+    db: &dyn DefDatabase,
+    def_map: &DefMap,
+    mut local_id: LocalModuleId,
+) -> (Arc<DefMap>, LocalModuleId) {
+    // INVARIANT: `local_id` in `def_map` must be a block module.
+    stdx::always!(def_map.module_id(local_id).is_block_module());
+
+    let mut ext;
+    // This needs to be a local variable due to our mighty lifetime.
+    let mut def_map = def_map;
+    loop {
+        let BlockInfo { parent, .. } = def_map.block.expect("block module without parent module");
+
+        ext = parent.def_map(db, def_map.krate);
+        def_map = &ext;
+        local_id = parent.local_id;
+        if !parent.is_block_module() {
+            return (ext, local_id);
+        }
+    }
+}

crates/hir-def/src/path.rs

@@ -45,7 +45,7 @@ pub enum Path {
         /// Invariant: the same len as `self.mod_path.segments` or `None` if all segments are `None`.
         generic_args: Option<Box<[Option<Interned<GenericArgs>>]>>,
     },
-    /// A link to a lang item. It is used in desugaring of things like `x?`. We can show these
+    /// A link to a lang item. It is used in desugaring of things like `it?`. We can show these
     /// links via a normal path since they might be private and not accessible in the usage place.
     LangItem(LangItemTarget),
 }
@@ -135,10 +135,7 @@ impl Path {
 
     pub fn segments(&self) -> PathSegments<'_> {
         let Path::Normal { mod_path, generic_args, .. } = self else {
-            return PathSegments {
+            return PathSegments { segments: &[], generic_args: None };
-                segments: &[],
-                generic_args: None,
-            };
         };
         let s =
             PathSegments { segments: mod_path.segments(), generic_args: generic_args.as_deref() };

crates/hir-def/src/path/lower.rs

@@ -74,8 +74,8 @@ pub(super) fn lower_path(mut path: ast::Path, ctx: &LowerCtx<'_>) -> Option<Path
                     // <T as Trait<A>>::Foo desugars to Trait<Self=T, A>::Foo
                     Some(trait_ref) => {
                         let Path::Normal { mod_path, generic_args: path_generic_args, .. } =
-                            Path::from_src(trait_ref.path()?, ctx)? else
+                            Path::from_src(trait_ref.path()?, ctx)?
-                        {
+                        else {
                             return None;
                         };
                         let num_segments = mod_path.segments().len();

crates/hir-def/src/pretty.rs

@@ -12,8 +12,8 @@ use crate::{
 };
 
 pub(crate) fn print_path(db: &dyn ExpandDatabase, path: &Path, buf: &mut dyn Write) -> fmt::Result {
-    if let Path::LangItem(x) = path {
+    if let Path::LangItem(it) = path {
-        return write!(buf, "$lang_item::{x:?}");
+        return write!(buf, "$lang_item::{it:?}");
     }
     match path.type_anchor() {
         Some(anchor) => {

crates/hir-def/src/resolver.rs

@@ -22,10 +22,10 @@ use crate::{
     per_ns::PerNs,
     visibility::{RawVisibility, Visibility},
     AdtId, AssocItemId, ConstId, ConstParamId, CrateRootModuleId, DefWithBodyId, EnumId,
-    EnumVariantId, ExternBlockId, FunctionId, GenericDefId, GenericParamId, HasModule, ImplId,
+    EnumVariantId, ExternBlockId, ExternCrateId, FunctionId, GenericDefId, GenericParamId,
-    ItemContainerId, LifetimeParamId, LocalModuleId, Lookup, Macro2Id, MacroId, MacroRulesId,
+    HasModule, ImplId, ItemContainerId, LifetimeParamId, LocalModuleId, Lookup, Macro2Id, MacroId,
-    ModuleDefId, ModuleId, ProcMacroId, StaticId, StructId, TraitAliasId, TraitId, TypeAliasId,
+    MacroRulesId, ModuleDefId, ModuleId, ProcMacroId, StaticId, StructId, TraitAliasId, TraitId,
-    TypeOrConstParamId, TypeOwnerId, TypeParamId, VariantId,
+    TypeAliasId, TypeOrConstParamId, TypeOwnerId, TypeParamId, VariantId,
 };
 
 #[derive(Debug, Clone)]
@@ -186,12 +186,12 @@ impl Resolver {
             Path::LangItem(l) => {
                 return Some((
                     match *l {
-                        LangItemTarget::Union(x) => TypeNs::AdtId(x.into()),
+                        LangItemTarget::Union(it) => TypeNs::AdtId(it.into()),
-                        LangItemTarget::TypeAlias(x) => TypeNs::TypeAliasId(x),
+                        LangItemTarget::TypeAlias(it) => TypeNs::TypeAliasId(it),
-                        LangItemTarget::Struct(x) => TypeNs::AdtId(x.into()),
+                        LangItemTarget::Struct(it) => TypeNs::AdtId(it.into()),
-                        LangItemTarget::EnumVariant(x) => TypeNs::EnumVariantId(x),
+                        LangItemTarget::EnumVariant(it) => TypeNs::EnumVariantId(it),
-                        LangItemTarget::EnumId(x) => TypeNs::AdtId(x.into()),
+                        LangItemTarget::EnumId(it) => TypeNs::AdtId(it.into()),
-                        LangItemTarget::Trait(x) => TypeNs::TraitId(x),
+                        LangItemTarget::Trait(it) => TypeNs::TraitId(it),
                         LangItemTarget::Function(_)
                         | LangItemTarget::ImplDef(_)
                         | LangItemTarget::Static(_) => return None,
@@ -273,10 +273,10 @@ impl Resolver {
             Path::Normal { mod_path, .. } => mod_path,
             Path::LangItem(l) => {
                 return Some(ResolveValueResult::ValueNs(match *l {
-                    LangItemTarget::Function(x) => ValueNs::FunctionId(x),
+                    LangItemTarget::Function(it) => ValueNs::FunctionId(it),
-                    LangItemTarget::Static(x) => ValueNs::StaticId(x),
+                    LangItemTarget::Static(it) => ValueNs::StaticId(it),
-                    LangItemTarget::Struct(x) => ValueNs::StructId(x),
+                    LangItemTarget::Struct(it) => ValueNs::StructId(it),
-                    LangItemTarget::EnumVariant(x) => ValueNs::EnumVariantId(x),
+                    LangItemTarget::EnumVariant(it) => ValueNs::EnumVariantId(it),
                     LangItemTarget::Union(_)
                     | LangItemTarget::ImplDef(_)
                     | LangItemTarget::TypeAlias(_)
@@ -425,14 +425,14 @@ impl Resolver {
     /// The shadowing is accounted for: in
     ///
     /// ```
-    /// let x = 92;
+    /// let it = 92;
     /// {
-    ///     let x = 92;
+    ///     let it = 92;
     ///     $0
     /// }
     /// ```
     ///
-    /// there will be only one entry for `x` in the result.
+    /// there will be only one entry for `it` in the result.
     ///
     /// The result is ordered *roughly* from the innermost scope to the
     /// outermost: when the name is introduced in two namespaces in two scopes,
@@ -1018,20 +1018,26 @@ impl HasResolver for ExternBlockId {
     }
 }
 
+impl HasResolver for ExternCrateId {
+    fn resolver(self, db: &dyn DefDatabase) -> Resolver {
+        self.lookup(db).container.resolver(db)
+    }
+}
+
 impl HasResolver for TypeOwnerId {
     fn resolver(self, db: &dyn DefDatabase) -> Resolver {
         match self {
-            TypeOwnerId::FunctionId(x) => x.resolver(db),
+            TypeOwnerId::FunctionId(it) => it.resolver(db),
-            TypeOwnerId::StaticId(x) => x.resolver(db),
+            TypeOwnerId::StaticId(it) => it.resolver(db),
-            TypeOwnerId::ConstId(x) => x.resolver(db),
+            TypeOwnerId::ConstId(it) => it.resolver(db),
-            TypeOwnerId::InTypeConstId(x) => x.lookup(db).owner.resolver(db),
+            TypeOwnerId::InTypeConstId(it) => it.lookup(db).owner.resolver(db),
-            TypeOwnerId::AdtId(x) => x.resolver(db),
+            TypeOwnerId::AdtId(it) => it.resolver(db),
-            TypeOwnerId::TraitId(x) => x.resolver(db),
+            TypeOwnerId::TraitId(it) => it.resolver(db),
-            TypeOwnerId::TraitAliasId(x) => x.resolver(db),
+            TypeOwnerId::TraitAliasId(it) => it.resolver(db),
-            TypeOwnerId::TypeAliasId(x) => x.resolver(db),
+            TypeOwnerId::TypeAliasId(it) => it.resolver(db),
-            TypeOwnerId::ImplId(x) => x.resolver(db),
+            TypeOwnerId::ImplId(it) => it.resolver(db),
-            TypeOwnerId::EnumVariantId(x) => x.resolver(db),
+            TypeOwnerId::EnumVariantId(it) => it.resolver(db),
-            TypeOwnerId::ModuleId(x) => x.resolver(db),
+            TypeOwnerId::ModuleId(it) => it.resolver(db),
         }
     }
 }

crates/hir-expand/Cargo.toml

@@ -16,11 +16,9 @@ cov-mark = "2.0.0-pre.1"
 tracing = "0.1.35"
 either = "1.7.0"
 rustc-hash = "1.1.0"
-la-arena = { version = "0.3.0", path = "../../lib/la-arena" }
+la-arena.workspace = true
 itertools = "0.10.5"
-hashbrown = { version = "0.12.1", features = [
+hashbrown.workspace = true
-    "inline-more",
-], default-features = false }
 smallvec.workspace = true
 triomphe.workspace = true
 

crates/hir-expand/src/ast_id_map.rs

@@ -18,47 +18,89 @@ use rustc_hash::FxHasher;
 use syntax::{ast, AstNode, AstPtr, SyntaxNode, SyntaxNodePtr};
 
 /// `AstId` points to an AST node in a specific file.
-pub struct FileAstId<N: AstNode> {
+pub struct FileAstId<N: AstIdNode> {
     raw: ErasedFileAstId,
     covariant: PhantomData<fn() -> N>,
 }
 
-impl<N: AstNode> Clone for FileAstId<N> {
+impl<N: AstIdNode> Clone for FileAstId<N> {
     fn clone(&self) -> FileAstId<N> {
         *self
     }
 }
-impl<N: AstNode> Copy for FileAstId<N> {}
+impl<N: AstIdNode> Copy for FileAstId<N> {}
 
-impl<N: AstNode> PartialEq for FileAstId<N> {
+impl<N: AstIdNode> PartialEq for FileAstId<N> {
     fn eq(&self, other: &Self) -> bool {
         self.raw == other.raw
     }
 }
-impl<N: AstNode> Eq for FileAstId<N> {}
+impl<N: AstIdNode> Eq for FileAstId<N> {}
-impl<N: AstNode> Hash for FileAstId<N> {
+impl<N: AstIdNode> Hash for FileAstId<N> {
     fn hash<H: Hasher>(&self, hasher: &mut H) {
         self.raw.hash(hasher);
     }
 }
 
-impl<N: AstNode> fmt::Debug for FileAstId<N> {
+impl<N: AstIdNode> fmt::Debug for FileAstId<N> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "FileAstId::<{}>({})", type_name::<N>(), self.raw.into_raw())
     }
 }
 
-impl<N: AstNode> FileAstId<N> {
+impl<N: AstIdNode> FileAstId<N> {
     // Can't make this a From implementation because of coherence
-    pub fn upcast<M: AstNode>(self) -> FileAstId<M>
+    pub fn upcast<M: AstIdNode>(self) -> FileAstId<M>
     where
         N: Into<M>,
     {
         FileAstId { raw: self.raw, covariant: PhantomData }
     }
+
+    pub fn erase(self) -> ErasedFileAstId {
+        self.raw
+    }
 }
 
-type ErasedFileAstId = Idx<SyntaxNodePtr>;
+pub type ErasedFileAstId = Idx<SyntaxNodePtr>;
+
+pub trait AstIdNode: AstNode {}
+macro_rules! register_ast_id_node {
+    (impl AstIdNode for $($ident:ident),+ ) => {
+        $(
+            impl AstIdNode for ast::$ident {}
+        )+
+        fn should_alloc_id(kind: syntax::SyntaxKind) -> bool {
+            $(
+                ast::$ident::can_cast(kind)
+            )||+
+        }
+    };
+}
+register_ast_id_node! {
+    impl AstIdNode for
+    Item,
+        Adt,
+            Enum,
+            Struct,
+            Union,
+        Const,
+        ExternBlock,
+        ExternCrate,
+        Fn,
+        Impl,
+        Macro,
+            MacroDef,
+            MacroRules,
+        MacroCall,
+        Module,
+        Static,
+        Trait,
+        TraitAlias,
+        TypeAlias,
+        Use,
+    AssocItem, BlockExpr, Variant, RecordField, TupleField, ConstArg
+}
 
 /// Maps items' `SyntaxNode`s to `ErasedFileAstId`s and back.
 #[derive(Default)]
@@ -92,14 +134,7 @@ impl AstIdMap {
         // 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| {
-            let kind = it.kind();
+            if should_alloc_id(it.kind()) {
-            if ast::Item::can_cast(kind)
-                || ast::BlockExpr::can_cast(kind)
-                || ast::Variant::can_cast(kind)
-                || ast::RecordField::can_cast(kind)
-                || ast::TupleField::can_cast(kind)
-                || ast::ConstArg::can_cast(kind)
-            {
                 res.alloc(&it);
                 true
             } else {
@@ -120,15 +155,19 @@ impl AstIdMap {
         res
     }
 
-    pub fn ast_id<N: AstNode>(&self, item: &N) -> FileAstId<N> {
+    pub fn ast_id<N: AstIdNode>(&self, item: &N) -> FileAstId<N> {
         let raw = self.erased_ast_id(item.syntax());
         FileAstId { raw, covariant: PhantomData }
     }
 
-    pub fn get<N: AstNode>(&self, id: FileAstId<N>) -> AstPtr<N> {
+    pub fn get<N: AstIdNode>(&self, id: FileAstId<N>) -> AstPtr<N> {
         AstPtr::try_from_raw(self.arena[id.raw].clone()).unwrap()
     }
 
+    pub(crate) fn get_raw(&self, id: ErasedFileAstId) -> SyntaxNodePtr {
+        self.arena[id].clone()
+    }
+
     fn erased_ast_id(&self, item: &SyntaxNode) -> ErasedFileAstId {
         let ptr = SyntaxNodePtr::new(item);
         let hash = hash_ptr(&ptr);

crates/hir-expand/src/builtin_attr_macro.rs

@@ -35,7 +35,7 @@ macro_rules! register_builtin {
 
 impl BuiltinAttrExpander {
     pub fn is_derive(self) -> bool {
-        matches!(self, BuiltinAttrExpander::Derive)
+        matches!(self, BuiltinAttrExpander::Derive | BuiltinAttrExpander::DeriveConst)
     }
     pub fn is_test(self) -> bool {
         matches!(self, BuiltinAttrExpander::Test)
@@ -50,6 +50,8 @@ register_builtin! {
     (cfg_accessible, CfgAccessible) => dummy_attr_expand,
     (cfg_eval, CfgEval) => dummy_attr_expand,
     (derive, Derive) => derive_attr_expand,
+    // derive const is equivalent to derive for our proposes.
+    (derive_const, DeriveConst) => derive_attr_expand,
     (global_allocator, GlobalAllocator) => dummy_attr_expand,
     (test, Test) => dummy_attr_expand,
     (test_case, TestCase) => dummy_attr_expand

crates/hir-expand/src/builtin_derive_macro.rs

@@ -12,9 +12,7 @@ use crate::{
     name::{AsName, Name},
     tt::{self, TokenId},
 };
-use syntax::ast::{
+use syntax::ast::{self, AstNode, FieldList, HasAttrs, HasGenericParams, HasName, HasTypeBounds};
-    self, AstNode, FieldList, HasAttrs, HasGenericParams, HasModuleItem, HasName, HasTypeBounds,
-};
 
 use crate::{db::ExpandDatabase, name, quote, ExpandError, ExpandResult, MacroCallId};
 
@@ -30,12 +28,13 @@ macro_rules! register_builtin {
                 &self,
                 db: &dyn ExpandDatabase,
                 id: MacroCallId,
-                tt: &tt::Subtree,
+                tt: &ast::Adt,
+                token_map: &TokenMap,
             ) -> ExpandResult<tt::Subtree> {
                 let expander = match *self {
                     $( BuiltinDeriveExpander::$trait => $expand, )*
                 };
-                expander(db, id, tt)
+                expander(db, id, tt, token_map)
             }
 
             fn find_by_name(name: &name::Name) -> Option<Self> {
@@ -72,12 +71,12 @@ enum VariantShape {
 }
 
 fn tuple_field_iterator(n: usize) -> impl Iterator<Item = tt::Ident> {
-    (0..n).map(|x| Ident::new(format!("f{x}"), tt::TokenId::unspecified()))
+    (0..n).map(|it| Ident::new(format!("f{it}"), tt::TokenId::unspecified()))
 }
 
 impl VariantShape {
     fn as_pattern(&self, path: tt::Subtree) -> tt::Subtree {
-        self.as_pattern_map(path, |x| quote!(#x))
+        self.as_pattern_map(path, |it| quote!(#it))
     }
 
     fn field_names(&self) -> Vec<tt::Ident> {
@@ -95,17 +94,17 @@ impl VariantShape {
     ) -> tt::Subtree {
         match self {
             VariantShape::Struct(fields) => {
-                let fields = fields.iter().map(|x| {
+                let fields = fields.iter().map(|it| {
-                    let mapped = field_map(x);
+                    let mapped = field_map(it);
-                    quote! { #x : #mapped , }
+                    quote! { #it : #mapped , }
                 });
                 quote! {
                     #path { ##fields }
                 }
             }
             &VariantShape::Tuple(n) => {
-                let fields = tuple_field_iterator(n).map(|x| {
+                let fields = tuple_field_iterator(n).map(|it| {
-                    let mapped = field_map(&x);
+                    let mapped = field_map(&it);
                     quote! {
                         #mapped ,
                     }
@@ -118,16 +117,16 @@ impl VariantShape {
         }
     }
 
-    fn from(value: Option<FieldList>, token_map: &TokenMap) -> Result<Self, ExpandError> {
+    fn from(tm: &TokenMap, value: Option<FieldList>) -> Result<Self, ExpandError> {
         let r = match value {
             None => VariantShape::Unit,
-            Some(FieldList::RecordFieldList(x)) => VariantShape::Struct(
+            Some(FieldList::RecordFieldList(it)) => VariantShape::Struct(
-                x.fields()
+                it.fields()
-                    .map(|x| x.name())
+                    .map(|it| it.name())
-                    .map(|x| name_to_token(token_map, x))
+                    .map(|it| name_to_token(tm, it))
                     .collect::<Result<_, _>>()?,
             ),
-            Some(FieldList::TupleFieldList(x)) => VariantShape::Tuple(x.fields().count()),
+            Some(FieldList::TupleFieldList(it)) => VariantShape::Tuple(it.fields().count()),
         };
         Ok(r)
     }
@@ -141,7 +140,7 @@ enum AdtShape {
 
 impl AdtShape {
     fn as_pattern(&self, name: &tt::Ident) -> Vec<tt::Subtree> {
-        self.as_pattern_map(name, |x| quote!(#x))
+        self.as_pattern_map(name, |it| quote!(#it))
     }
 
     fn field_names(&self) -> Vec<Vec<tt::Ident>> {
@@ -190,32 +189,19 @@ struct BasicAdtInfo {
     associated_types: Vec<tt::Subtree>,
 }
 
-fn parse_adt(tt: &tt::Subtree) -> Result<BasicAdtInfo, ExpandError> {
+fn parse_adt(tm: &TokenMap, adt: &ast::Adt) -> Result<BasicAdtInfo, ExpandError> {
-    let (parsed, token_map) = mbe::token_tree_to_syntax_node(tt, mbe::TopEntryPoint::MacroItems);
-    let macro_items = ast::MacroItems::cast(parsed.syntax_node()).ok_or_else(|| {
-        debug!("derive node didn't parse");
-        ExpandError::other("invalid item definition")
-    })?;
-    let item = macro_items.items().next().ok_or_else(|| {
-        debug!("no module item parsed");
-        ExpandError::other("no item found")
-    })?;
-    let adt = ast::Adt::cast(item.syntax().clone()).ok_or_else(|| {
-        debug!("expected adt, found: {:?}", item);
-        ExpandError::other("expected struct, enum or union")
-    })?;
     let (name, generic_param_list, shape) = match &adt {
         ast::Adt::Struct(it) => (
             it.name(),
             it.generic_param_list(),
-            AdtShape::Struct(VariantShape::from(it.field_list(), &token_map)?),
+            AdtShape::Struct(VariantShape::from(tm, it.field_list())?),
         ),
         ast::Adt::Enum(it) => {
             let default_variant = it
                 .variant_list()
                 .into_iter()
-                .flat_map(|x| x.variants())
+                .flat_map(|it| it.variants())
-                .position(|x| x.attrs().any(|x| x.simple_name() == Some("default".into())));
+                .position(|it| it.attrs().any(|it| it.simple_name() == Some("default".into())));
             (
                 it.name(),
                 it.generic_param_list(),
@@ -224,11 +210,11 @@ fn parse_adt(tt: &tt::Subtree) -> Result<BasicAdtInfo, ExpandError> {
                     variants: it
                         .variant_list()
                         .into_iter()
-                        .flat_map(|x| x.variants())
+                        .flat_map(|it| it.variants())
-                        .map(|x| {
+                        .map(|it| {
                             Ok((
-                                name_to_token(&token_map, x.name())?,
+                                name_to_token(tm, it.name())?,
-                                VariantShape::from(x.field_list(), &token_map)?,
+                                VariantShape::from(tm, it.field_list())?,
                             ))
                         })
                         .collect::<Result<_, ExpandError>>()?,
@@ -246,16 +232,16 @@ fn parse_adt(tt: &tt::Subtree) -> Result<BasicAdtInfo, ExpandError> {
             let name = {
                 let this = param.name();
                 match this {
-                    Some(x) => {
+                    Some(it) => {
-                        param_type_set.insert(x.as_name());
+                        param_type_set.insert(it.as_name());
-                        mbe::syntax_node_to_token_tree(x.syntax()).0
+                        mbe::syntax_node_to_token_tree(it.syntax()).0
                     }
                     None => tt::Subtree::empty(),
                 }
             };
             let bounds = match &param {
-                ast::TypeOrConstParam::Type(x) => {
+                ast::TypeOrConstParam::Type(it) => {
-                    x.type_bound_list().map(|x| mbe::syntax_node_to_token_tree(x.syntax()).0)
+                    it.type_bound_list().map(|it| mbe::syntax_node_to_token_tree(it.syntax()).0)
                 }
                 ast::TypeOrConstParam::Const(_) => None,
             };
@@ -296,9 +282,9 @@ fn parse_adt(tt: &tt::Subtree) -> Result<BasicAdtInfo, ExpandError> {
             let name = p.path()?.qualifier()?.as_single_name_ref()?.as_name();
             param_type_set.contains(&name).then_some(p)
         })
-        .map(|x| mbe::syntax_node_to_token_tree(x.syntax()).0)
+        .map(|it| mbe::syntax_node_to_token_tree(it.syntax()).0)
         .collect();
-    let name_token = name_to_token(&token_map, name)?;
+    let name_token = name_to_token(&tm, name)?;
     Ok(BasicAdtInfo { name: name_token, shape, param_types, associated_types })
 }
 
@@ -345,11 +331,12 @@ fn name_to_token(token_map: &TokenMap, name: Option<ast::Name>) -> Result<tt::Id
 /// where B1, ..., BN are the bounds given by `bounds_paths`. Z is a phantom type, and
 /// therefore does not get bound by the derived trait.
 fn expand_simple_derive(
-    tt: &tt::Subtree,
+    tt: &ast::Adt,
+    tm: &TokenMap,
     trait_path: tt::Subtree,
     make_trait_body: impl FnOnce(&BasicAdtInfo) -> tt::Subtree,
 ) -> ExpandResult<tt::Subtree> {
-    let info = match parse_adt(tt) {
+    let info = match parse_adt(tm, tt) {
         Ok(info) => info,
         Err(e) => return ExpandResult::new(tt::Subtree::empty(), e),
     };
@@ -373,10 +360,10 @@ fn expand_simple_derive(
         })
         .unzip();
 
-    where_block.extend(info.associated_types.iter().map(|x| {
+    where_block.extend(info.associated_types.iter().map(|it| {
-        let x = x.clone();
+        let it = it.clone();
         let bound = trait_path.clone();
-        quote! { #x : #bound , }
+        quote! { #it : #bound , }
     }));
 
     let name = info.name;
@@ -405,19 +392,21 @@ fn find_builtin_crate(db: &dyn ExpandDatabase, id: MacroCallId) -> tt::TokenTree
 fn copy_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
-    tt: &tt::Subtree,
+    tt: &ast::Adt,
+    tm: &TokenMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = find_builtin_crate(db, id);
-    expand_simple_derive(tt, quote! { #krate::marker::Copy }, |_| quote! {})
+    expand_simple_derive(tt, tm, quote! { #krate::marker::Copy }, |_| quote! {})
 }
 
 fn clone_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
-    tt: &tt::Subtree,
+    tt: &ast::Adt,
+    tm: &TokenMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = find_builtin_crate(db, id);
-    expand_simple_derive(tt, quote! { #krate::clone::Clone }, |adt| {
+    expand_simple_derive(tt, tm, quote! { #krate::clone::Clone }, |adt| {
         if matches!(adt.shape, AdtShape::Union) {
             let star = tt::Punct {
                 char: '*',
@@ -444,7 +433,7 @@ fn clone_expand(
         }
         let name = &adt.name;
         let patterns = adt.shape.as_pattern(name);
-        let exprs = adt.shape.as_pattern_map(name, |x| quote! { #x .clone() });
+        let exprs = adt.shape.as_pattern_map(name, |it| quote! { #it .clone() });
         let arms = patterns.into_iter().zip(exprs.into_iter()).map(|(pat, expr)| {
             let fat_arrow = fat_arrow();
             quote! {
@@ -479,10 +468,11 @@ fn and_and() -> ::tt::Subtree<TokenId> {
 fn default_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
-    tt: &tt::Subtree,
+    tt: &ast::Adt,
+    tm: &TokenMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = &find_builtin_crate(db, id);
-    expand_simple_derive(tt, quote! { #krate::default::Default }, |adt| {
+    expand_simple_derive(tt, tm, quote! { #krate::default::Default }, |adt| {
         let body = match &adt.shape {
             AdtShape::Struct(fields) => {
                 let name = &adt.name;
@@ -518,16 +508,17 @@ fn default_expand(
 fn debug_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
-    tt: &tt::Subtree,
+    tt: &ast::Adt,
+    tm: &TokenMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = &find_builtin_crate(db, id);
-    expand_simple_derive(tt, quote! { #krate::fmt::Debug }, |adt| {
+    expand_simple_derive(tt, tm, quote! { #krate::fmt::Debug }, |adt| {
         let for_variant = |name: String, v: &VariantShape| match v {
             VariantShape::Struct(fields) => {
-                let for_fields = fields.iter().map(|x| {
+                let for_fields = fields.iter().map(|it| {
-                    let x_string = x.to_string();
+                    let x_string = it.to_string();
                     quote! {
-                        .field(#x_string, & #x)
+                        .field(#x_string, & #it)
                     }
                 });
                 quote! {
@@ -535,9 +526,9 @@ fn debug_expand(
                 }
             }
             VariantShape::Tuple(n) => {
-                let for_fields = tuple_field_iterator(*n).map(|x| {
+                let for_fields = tuple_field_iterator(*n).map(|it| {
                     quote! {
-                        .field( & #x)
+                        .field( & #it)
                     }
                 });
                 quote! {
@@ -598,10 +589,11 @@ fn debug_expand(
 fn hash_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
-    tt: &tt::Subtree,
+    tt: &ast::Adt,
+    tm: &TokenMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = &find_builtin_crate(db, id);
-    expand_simple_derive(tt, quote! { #krate::hash::Hash }, |adt| {
+    expand_simple_derive(tt, tm, quote! { #krate::hash::Hash }, |adt| {
         if matches!(adt.shape, AdtShape::Union) {
             // FIXME: Return expand error here
             return quote! {};
@@ -621,7 +613,7 @@ fn hash_expand(
         let arms = adt.shape.as_pattern(&adt.name).into_iter().zip(adt.shape.field_names()).map(
             |(pat, names)| {
                 let expr = {
-                    let it = names.iter().map(|x| quote! { #x . hash(ra_expand_state); });
+                    let it = names.iter().map(|it| quote! { #it . hash(ra_expand_state); });
                     quote! { {
                         ##it
                     } }
@@ -632,9 +624,14 @@ fn hash_expand(
                 }
             },
         );
+        let check_discriminant = if matches!(&adt.shape, AdtShape::Enum { .. }) {
+            quote! { #krate::mem::discriminant(self).hash(ra_expand_state); }
+        } else {
+            quote! {}
+        };
         quote! {
             fn hash<H: #krate::hash::Hasher>(&self, ra_expand_state: &mut H) {
-                #krate::mem::discriminant(self).hash(ra_expand_state);
+                #check_discriminant
                 match self {
                     ##arms
                 }
@@ -646,19 +643,21 @@ fn hash_expand(
 fn eq_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
-    tt: &tt::Subtree,
+    tt: &ast::Adt,
+    tm: &TokenMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = find_builtin_crate(db, id);
-    expand_simple_derive(tt, quote! { #krate::cmp::Eq }, |_| quote! {})
+    expand_simple_derive(tt, tm, quote! { #krate::cmp::Eq }, |_| quote! {})
 }
 
 fn partial_eq_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
-    tt: &tt::Subtree,
+    tt: &ast::Adt,
+    tm: &TokenMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = find_builtin_crate(db, id);
-    expand_simple_derive(tt, quote! { #krate::cmp::PartialEq }, |adt| {
+    expand_simple_derive(tt, tm, quote! { #krate::cmp::PartialEq }, |adt| {
         if matches!(adt.shape, AdtShape::Union) {
             // FIXME: Return expand error here
             return quote! {};
@@ -674,9 +673,9 @@ fn partial_eq_expand(
                         quote!(true)
                     }
                     [first, rest @ ..] => {
-                        let rest = rest.iter().map(|x| {
+                        let rest = rest.iter().map(|it| {
-                            let t1 = Ident::new(format!("{}_self", x.text), x.span);
+                            let t1 = Ident::new(format!("{}_self", it.text), it.span);
-                            let t2 = Ident::new(format!("{}_other", x.text), x.span);
+                            let t2 = Ident::new(format!("{}_other", it.text), it.span);
                             let and_and = and_and();
                             quote!(#and_and #t1 .eq( #t2 ))
                         });
@@ -708,12 +707,12 @@ fn self_and_other_patterns(
     adt: &BasicAdtInfo,
     name: &tt::Ident,
 ) -> (Vec<tt::Subtree>, Vec<tt::Subtree>) {
-    let self_patterns = adt.shape.as_pattern_map(name, |x| {
+    let self_patterns = adt.shape.as_pattern_map(name, |it| {
-        let t = Ident::new(format!("{}_self", x.text), x.span);
+        let t = Ident::new(format!("{}_self", it.text), it.span);
         quote!(#t)
     });
-    let other_patterns = adt.shape.as_pattern_map(name, |x| {
+    let other_patterns = adt.shape.as_pattern_map(name, |it| {
-        let t = Ident::new(format!("{}_other", x.text), x.span);
+        let t = Ident::new(format!("{}_other", it.text), it.span);
         quote!(#t)
     });
     (self_patterns, other_patterns)
@@ -722,10 +721,11 @@ fn self_and_other_patterns(
 fn ord_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
-    tt: &tt::Subtree,
+    tt: &ast::Adt,
+    tm: &TokenMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = &find_builtin_crate(db, id);
-    expand_simple_derive(tt, quote! { #krate::cmp::Ord }, |adt| {
+    expand_simple_derive(tt, tm, quote! { #krate::cmp::Ord }, |adt| {
         fn compare(
             krate: &tt::TokenTree,
             left: tt::Subtree,
@@ -747,9 +747,6 @@ fn ord_expand(
             // FIXME: Return expand error here
             return quote!();
         }
-        let left = quote!(#krate::intrinsics::discriminant_value(self));
-        let right = quote!(#krate::intrinsics::discriminant_value(other));
-
         let (self_patterns, other_patterns) = self_and_other_patterns(adt, &adt.name);
         let arms = izip!(self_patterns, other_patterns, adt.shape.field_names()).map(
             |(pat1, pat2, fields)| {
@@ -764,17 +761,17 @@ fn ord_expand(
             },
         );
         let fat_arrow = fat_arrow();
-        let body = compare(
+        let mut body = quote! {
-            krate,
+            match (self, other) {
-            left,
+                ##arms
-            right,
+                _unused #fat_arrow #krate::cmp::Ordering::Equal
-            quote! {
+            }
-                match (self, other) {
+        };
-                    ##arms
+        if matches!(&adt.shape, AdtShape::Enum { .. }) {
-                    _unused #fat_arrow #krate::cmp::Ordering::Equal
+            let left = quote!(#krate::intrinsics::discriminant_value(self));
-                }
+            let right = quote!(#krate::intrinsics::discriminant_value(other));
-            },
+            body = compare(krate, left, right, body);
-        );
+        }
         quote! {
             fn cmp(&self, other: &Self) -> #krate::cmp::Ordering {
                 #body
@@ -786,10 +783,11 @@ fn ord_expand(
 fn partial_ord_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
-    tt: &tt::Subtree,
+    tt: &ast::Adt,
+    tm: &TokenMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = &find_builtin_crate(db, id);
-    expand_simple_derive(tt, quote! { #krate::cmp::PartialOrd }, |adt| {
+    expand_simple_derive(tt, tm, quote! { #krate::cmp::PartialOrd }, |adt| {
         fn compare(
             krate: &tt::TokenTree,
             left: tt::Subtree,

crates/hir-expand/src/builtin_fn_macro.rs

@@ -339,7 +339,7 @@ fn format_args_expand_general(
                 parts.push(mem::take(&mut last_part));
                 let arg_tree = if argument.is_empty() {
                     match args.next() {
-                        Some(x) => x,
+                        Some(it) => it,
                         None => {
                             err = Some(mbe::ExpandError::NoMatchingRule.into());
                             tt::Subtree::empty()
@@ -361,7 +361,7 @@ fn format_args_expand_general(
                         quote!(::core::fmt::Display::fmt)
                     }
                 };
-                arg_tts.push(quote! { ::core::fmt::Argument::new(&(#arg_tree), #formatter), });
+                arg_tts.push(quote! { ::core::fmt::ArgumentV1::new(&(#arg_tree), #formatter), });
             }
             '}' => {
                 if format_iter.peek() == Some(&'}') {
@@ -378,11 +378,11 @@ fn format_args_expand_general(
     if !last_part.is_empty() {
         parts.push(last_part);
     }
-    let part_tts = parts.into_iter().map(|x| {
+    let part_tts = parts.into_iter().map(|it| {
         let text = if let Some(raw) = &raw_sharps {
-            format!("r{raw}\"{}\"{raw}", x).into()
+            format!("r{raw}\"{}\"{raw}", it).into()
         } else {
-            format!("\"{}\"", x).into()
+            format!("\"{}\"", it).into()
         };
         let l = tt::Literal { span: tt::TokenId::unspecified(), text };
         quote!(#l ,)
@@ -574,7 +574,7 @@ fn concat_bytes_expand(
                     syntax::SyntaxKind::BYTE => bytes.push(token.text().to_string()),
                     syntax::SyntaxKind::BYTE_STRING => {
                         let components = unquote_byte_string(lit).unwrap_or_default();
-                        components.into_iter().for_each(|x| bytes.push(x.to_string()));
+                        components.into_iter().for_each(|it| bytes.push(it.to_string()));
                     }
                     _ => {
                         err.get_or_insert(mbe::ExpandError::UnexpectedToken.into());
@@ -692,7 +692,7 @@ pub(crate) fn include_arg_to_tt(
     arg_id: MacroCallId,
 ) -> Result<(triomphe::Arc<(::tt::Subtree<::tt::TokenId>, TokenMap)>, FileId), ExpandError> {
     let loc = db.lookup_intern_macro_call(arg_id);
-    let Some(EagerCallInfo {arg, arg_id: Some(arg_id), .. }) = loc.eager.as_deref() else {
+    let Some(EagerCallInfo { arg,arg_id, .. }) = loc.eager.as_deref() else {
         panic!("include_arg_to_tt called on non include macro call: {:?}", &loc.eager);
     };
     let path = parse_string(&arg.0)?;

crates/hir-expand/src/db.rs

@@ -1,9 +1,9 @@
 //! Defines database & queries for macro expansion.
 
-use base_db::{salsa, Edition, SourceDatabase};
+use base_db::{salsa, CrateId, Edition, SourceDatabase};
 use either::Either;
 use limit::Limit;
-use mbe::syntax_node_to_token_tree;
+use mbe::{syntax_node_to_token_tree, ValueResult};
 use rustc_hash::FxHashSet;
 use syntax::{
     ast::{self, HasAttrs, HasDocComments},
@@ -13,7 +13,7 @@ use triomphe::Arc;
 
 use crate::{
     ast_id_map::AstIdMap, builtin_attr_macro::pseudo_derive_attr_expansion,
-    builtin_fn_macro::EagerExpander, fixup, hygiene::HygieneFrame, tt, BuiltinAttrExpander,
+    builtin_fn_macro::EagerExpander, fixup, hygiene::HygieneFrame, tt, AstId, BuiltinAttrExpander,
     BuiltinDeriveExpander, BuiltinFnLikeExpander, EagerCallInfo, ExpandError, ExpandResult,
     ExpandTo, HirFileId, HirFileIdRepr, MacroCallId, MacroCallKind, MacroCallLoc, MacroDefId,
     MacroDefKind, MacroFile, ProcMacroExpander,
@@ -27,62 +27,68 @@ use crate::{
 /// Actual max for `analysis-stats .` at some point: 30672.
 static TOKEN_LIMIT: Limit = Limit::new(1_048_576);
 
+#[derive(Debug, Clone, Eq, PartialEq)]
+/// Old-style `macro_rules` or the new macros 2.0
+pub struct DeclarativeMacroExpander {
+    pub mac: mbe::DeclarativeMacro,
+    pub def_site_token_map: mbe::TokenMap,
+}
+
+impl DeclarativeMacroExpander {
+    pub fn expand(&self, tt: tt::Subtree) -> ExpandResult<tt::Subtree> {
+        match self.mac.err() {
+            Some(e) => ExpandResult::new(
+                tt::Subtree::empty(),
+                ExpandError::other(format!("invalid macro definition: {e}")),
+            ),
+            None => self.mac.expand(tt).map_err(Into::into),
+        }
+    }
+
+    pub fn map_id_down(&self, token_id: tt::TokenId) -> tt::TokenId {
+        self.mac.map_id_down(token_id)
+    }
+
+    pub fn map_id_up(&self, token_id: tt::TokenId) -> (tt::TokenId, mbe::Origin) {
+        self.mac.map_id_up(token_id)
+    }
+}
+
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub enum TokenExpander {
-    /// Old-style `macro_rules` or the new macros 2.0
+    DeclarativeMacro(Arc<DeclarativeMacroExpander>),
-    DeclarativeMacro { mac: mbe::DeclarativeMacro, def_site_token_map: mbe::TokenMap },
     /// Stuff like `line!` and `file!`.
-    Builtin(BuiltinFnLikeExpander),
+    BuiltIn(BuiltinFnLikeExpander),
     /// Built-in eagerly expanded fn-like macros (`include!`, `concat!`, etc.)
-    BuiltinEager(EagerExpander),
+    BuiltInEager(EagerExpander),
     /// `global_allocator` and such.
-    BuiltinAttr(BuiltinAttrExpander),
+    BuiltInAttr(BuiltinAttrExpander),
     /// `derive(Copy)` and such.
-    BuiltinDerive(BuiltinDeriveExpander),
+    BuiltInDerive(BuiltinDeriveExpander),
     /// The thing we love the most here in rust-analyzer -- procedural macros.
     ProcMacro(ProcMacroExpander),
 }
 
+// FIXME: Get rid of these methods
 impl TokenExpander {
-    fn expand(
-        &self,
-        db: &dyn ExpandDatabase,
-        id: MacroCallId,
-        tt: &tt::Subtree,
-    ) -> ExpandResult<tt::Subtree> {
-        match self {
-            TokenExpander::DeclarativeMacro { mac, .. } => mac.expand(tt).map_err(Into::into),
-            TokenExpander::Builtin(it) => it.expand(db, id, tt).map_err(Into::into),
-            TokenExpander::BuiltinEager(it) => it.expand(db, id, tt).map_err(Into::into),
-            TokenExpander::BuiltinAttr(it) => it.expand(db, id, tt),
-            TokenExpander::BuiltinDerive(it) => it.expand(db, id, tt),
-            TokenExpander::ProcMacro(_) => {
-                // We store the result in salsa db to prevent non-deterministic behavior in
-                // some proc-macro implementation
-                // See #4315 for details
-                db.expand_proc_macro(id)
-            }
-        }
-    }
-
     pub(crate) fn map_id_down(&self, id: tt::TokenId) -> tt::TokenId {
         match self {
-            TokenExpander::DeclarativeMacro { mac, .. } => mac.map_id_down(id),
+            TokenExpander::DeclarativeMacro(expander) => expander.map_id_down(id),
-            TokenExpander::Builtin(..)
+            TokenExpander::BuiltIn(..)
-            | TokenExpander::BuiltinEager(..)
+            | TokenExpander::BuiltInEager(..)
-            | TokenExpander::BuiltinAttr(..)
+            | TokenExpander::BuiltInAttr(..)
-            | TokenExpander::BuiltinDerive(..)
+            | TokenExpander::BuiltInDerive(..)
             | TokenExpander::ProcMacro(..) => id,
         }
     }
 
     pub(crate) fn map_id_up(&self, id: tt::TokenId) -> (tt::TokenId, mbe::Origin) {
         match self {
-            TokenExpander::DeclarativeMacro { mac, .. } => mac.map_id_up(id),
+            TokenExpander::DeclarativeMacro(expander) => expander.map_id_up(id),
-            TokenExpander::Builtin(..)
+            TokenExpander::BuiltIn(..)
-            | TokenExpander::BuiltinEager(..)
+            | TokenExpander::BuiltInEager(..)
-            | TokenExpander::BuiltinAttr(..)
+            | TokenExpander::BuiltInAttr(..)
-            | TokenExpander::BuiltinDerive(..)
+            | TokenExpander::BuiltInDerive(..)
             | TokenExpander::ProcMacro(..) => (id, mbe::Origin::Call),
         }
     }
@@ -118,14 +124,26 @@ pub trait ExpandDatabase: SourceDatabase {
     fn macro_arg(
         &self,
         id: MacroCallId,
-    ) -> Option<Arc<(tt::Subtree, mbe::TokenMap, fixup::SyntaxFixupUndoInfo)>>;
+    ) -> ValueResult<
+        Option<Arc<(tt::Subtree, mbe::TokenMap, fixup::SyntaxFixupUndoInfo)>>,
+        Arc<Box<[SyntaxError]>>,
+    >;
     /// Extracts syntax node, corresponding to a macro call. That's a firewall
     /// query, only typing in the macro call itself changes the returned
     /// subtree.
-    fn macro_arg_text(&self, id: MacroCallId) -> Option<GreenNode>;
+    fn macro_arg_node(
-    /// Gets the expander for this macro. This compiles declarative macros, and
+        &self,
-    /// just fetches procedural ones.
+        id: MacroCallId,
-    fn macro_def(&self, id: MacroDefId) -> Result<Arc<TokenExpander>, mbe::ParseError>;
+    ) -> ValueResult<Option<GreenNode>, Arc<Box<[SyntaxError]>>>;
+    /// Fetches the expander for this macro.
+    #[salsa::transparent]
+    fn macro_expander(&self, id: MacroDefId) -> TokenExpander;
+    /// Fetches (and compiles) the expander of this decl macro.
+    fn decl_macro_expander(
+        &self,
+        def_crate: CrateId,
+        id: AstId<ast::Macro>,
+    ) -> Arc<DeclarativeMacroExpander>;
 
     /// Expand macro call to a token tree.
     // This query is LRU cached
@@ -141,8 +159,8 @@ pub trait ExpandDatabase: SourceDatabase {
     /// Special case of the previous query for procedural macros. We can't LRU
     /// proc macros, since they are not deterministic in general, and
     /// non-determinism breaks salsa in a very, very, very bad way.
-    /// @edwin0cheng heroically debugged this once!
+    /// @edwin0cheng heroically debugged this once! See #4315 for details
-    fn expand_proc_macro(&self, call: MacroCallId) -> ExpandResult<tt::Subtree>;
+    fn expand_proc_macro(&self, call: MacroCallId) -> ExpandResult<Arc<tt::Subtree>>;
     /// Firewall query that returns the errors from the `parse_macro_expansion` query.
     fn parse_macro_expansion_error(
         &self,
@@ -163,7 +181,6 @@ pub fn expand_speculative(
     token_to_map: SyntaxToken,
 ) -> Option<(SyntaxNode, SyntaxToken)> {
     let loc = db.lookup_intern_macro_call(actual_macro_call);
-    let macro_def = db.macro_def(loc.def).ok()?;
     let token_range = token_to_map.text_range();
 
     // Build the subtree and token mapping for the speculative args
@@ -221,7 +238,12 @@ pub fn expand_speculative(
         None => {
             let range = token_range.checked_sub(speculative_args.text_range().start())?;
             let token_id = spec_args_tmap.token_by_range(range)?;
-            macro_def.map_id_down(token_id)
+            match loc.def.kind {
+                MacroDefKind::Declarative(it) => {
+                    db.decl_macro_expander(loc.krate, it).map_id_down(token_id)
+                }
+                _ => token_id,
+            }
         }
     };
 
@@ -235,7 +257,17 @@ pub fn expand_speculative(
         MacroDefKind::BuiltInAttr(BuiltinAttrExpander::Derive, _) => {
             pseudo_derive_attr_expansion(&tt, attr_arg.as_ref()?)
         }
-        _ => macro_def.expand(db, actual_macro_call, &tt),
+        MacroDefKind::BuiltInDerive(expander, ..) => {
+            // this cast is a bit sus, can we avoid losing the typedness here?
+            let adt = ast::Adt::cast(speculative_args.clone()).unwrap();
+            expander.expand(db, actual_macro_call, &adt, &spec_args_tmap)
+        }
+        MacroDefKind::Declarative(it) => db.decl_macro_expander(loc.krate, it).expand(tt),
+        MacroDefKind::BuiltIn(it, _) => it.expand(db, actual_macro_call, &tt).map_err(Into::into),
+        MacroDefKind::BuiltInEager(it, _) => {
+            it.expand(db, actual_macro_call, &tt).map_err(Into::into)
+        }
+        MacroDefKind::BuiltInAttr(it, _) => it.expand(db, actual_macro_call, &tt),
     };
 
     let expand_to = macro_expand_to(db, actual_macro_call);
@@ -297,17 +329,31 @@ fn parse_macro_expansion(
     ExpandResult { value: (parse, Arc::new(rev_token_map)), err }
 }
 
+fn parse_macro_expansion_error(
+    db: &dyn ExpandDatabase,
+    macro_call_id: MacroCallId,
+) -> ExpandResult<Box<[SyntaxError]>> {
+    db.parse_macro_expansion(MacroFile { macro_call_id })
+        .map(|it| it.0.errors().to_vec().into_boxed_slice())
+}
+
 fn macro_arg(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
-) -> Option<Arc<(tt::Subtree, mbe::TokenMap, fixup::SyntaxFixupUndoInfo)>> {
+) -> ValueResult<
+    Option<Arc<(tt::Subtree, mbe::TokenMap, fixup::SyntaxFixupUndoInfo)>>,
+    Arc<Box<[SyntaxError]>>,
+> {
     let loc = db.lookup_intern_macro_call(id);
 
-    if let Some(EagerCallInfo { arg, arg_id: Some(_), error: _ }) = loc.eager.as_deref() {
+    if let Some(EagerCallInfo { arg, arg_id: _, error: _ }) = loc.eager.as_deref() {
-        return Some(Arc::new((arg.0.clone(), arg.1.clone(), Default::default())));
+        return ValueResult::ok(Some(Arc::new((arg.0.clone(), arg.1.clone(), Default::default()))));
     }
 
-    let arg = db.macro_arg_text(id)?;
+    let ValueResult { value, err } = db.macro_arg_node(id);
+    let Some(arg) = value else {
+        return ValueResult { value: None, err };
+    };
 
     let node = SyntaxNode::new_root(arg);
     let censor = censor_for_macro_input(&loc, &node);
@@ -325,9 +371,16 @@ fn macro_arg(
         // proc macros expect their inputs without parentheses, MBEs expect it with them included
         tt.delimiter = tt::Delimiter::unspecified();
     }
-    Some(Arc::new((tt, tmap, fixups.undo_info)))
+    let val = Some(Arc::new((tt, tmap, fixups.undo_info)));
+    match err {
+        Some(err) => ValueResult::new(val, err),
+        None => ValueResult::ok(val),
+    }
 }
 
+/// Certain macro calls expect some nodes in the input to be preprocessed away, namely:
+/// - derives expect all `#[derive(..)]` invocations up to the currently invoked one to be stripped
+/// - attributes expect the invoking attribute to be stripped
 fn censor_for_macro_input(loc: &MacroCallLoc, node: &SyntaxNode) -> FxHashSet<SyntaxNode> {
     // FIXME: handle `cfg_attr`
     (|| {
@@ -364,9 +417,44 @@ fn censor_for_macro_input(loc: &MacroCallLoc, node: &SyntaxNode) -> FxHashSet<Sy
     .unwrap_or_default()
 }
 
-fn macro_arg_text(db: &dyn ExpandDatabase, id: MacroCallId) -> Option<GreenNode> {
+fn macro_arg_node(
+    db: &dyn ExpandDatabase,
+    id: MacroCallId,
+) -> ValueResult<Option<GreenNode>, Arc<Box<[SyntaxError]>>> {
+    let err = || -> Arc<Box<[_]>> {
+        Arc::new(Box::new([SyntaxError::new_at_offset(
+            "invalid macro call".to_owned(),
+            syntax::TextSize::from(0),
+        )]))
+    };
     let loc = db.lookup_intern_macro_call(id);
-    let arg = loc.kind.arg(db)?;
+    let arg = if let MacroDefKind::BuiltInEager(..) = loc.def.kind {
+        let res = if let Some(EagerCallInfo { arg, .. }) = loc.eager.as_deref() {
+            Some(mbe::token_tree_to_syntax_node(&arg.0, mbe::TopEntryPoint::Expr).0)
+        } else {
+            loc.kind
+                .arg(db)
+                .and_then(|arg| ast::TokenTree::cast(arg.value))
+                .map(|tt| tt.reparse_as_expr().to_syntax())
+        };
+
+        match res {
+            Some(res) if res.errors().is_empty() => res.syntax_node(),
+            Some(res) => {
+                return ValueResult::new(
+                    Some(res.syntax_node().green().into()),
+                    // Box::<[_]>::from(res.errors()), not stable yet
+                    Arc::new(res.errors().to_vec().into_boxed_slice()),
+                );
+            }
+            None => return ValueResult::only_err(err()),
+        }
+    } else {
+        match loc.kind.arg(db) {
+            Some(res) => res.value,
+            None => return ValueResult::only_err(err()),
+        }
+    };
     if matches!(loc.kind, MacroCallKind::FnLike { .. }) {
         let first = arg.first_child_or_token().map_or(T![.], |it| it.kind());
         let last = arg.last_child_or_token().map_or(T![.], |it| it.kind());
@@ -381,101 +469,146 @@ fn macro_arg_text(db: &dyn ExpandDatabase, id: MacroCallId) -> Option<GreenNode>
             // Some day, we'll have explicit recursion counters for all
             // recursive things, at which point this code might be removed.
             cov_mark::hit!(issue9358_bad_macro_stack_overflow);
-            return None;
+            return ValueResult::only_err(Arc::new(Box::new([SyntaxError::new(
+                "unbalanced token tree".to_owned(),
+                arg.text_range(),
+            )])));
         }
     }
-    if let Some(EagerCallInfo { arg, .. }) = loc.eager.as_deref() {
+    ValueResult::ok(Some(arg.green().into()))
-        Some(
-            mbe::token_tree_to_syntax_node(&arg.0, mbe::TopEntryPoint::Expr)
-                .0
-                .syntax_node()
-                .green()
-                .into(),
-        )
-    } else {
-        Some(arg.green().into())
-    }
 }
 
-fn macro_def(
+fn decl_macro_expander(
     db: &dyn ExpandDatabase,
-    id: MacroDefId,
+    def_crate: CrateId,
-) -> Result<Arc<TokenExpander>, mbe::ParseError> {
+    id: AstId<ast::Macro>,
+) -> Arc<DeclarativeMacroExpander> {
+    let is_2021 = db.crate_graph()[def_crate].edition >= Edition::Edition2021;
+    let (mac, def_site_token_map) = match id.to_node(db) {
+        ast::Macro::MacroRules(macro_rules) => match macro_rules.token_tree() {
+            Some(arg) => {
+                let (tt, def_site_token_map) = mbe::syntax_node_to_token_tree(arg.syntax());
+                let mac = mbe::DeclarativeMacro::parse_macro_rules(&tt, is_2021);
+                (mac, def_site_token_map)
+            }
+            None => (
+                mbe::DeclarativeMacro::from_err(
+                    mbe::ParseError::Expected("expected a token tree".into()),
+                    is_2021,
+                ),
+                Default::default(),
+            ),
+        },
+        ast::Macro::MacroDef(macro_def) => match macro_def.body() {
+            Some(arg) => {
+                let (tt, def_site_token_map) = mbe::syntax_node_to_token_tree(arg.syntax());
+                let mac = mbe::DeclarativeMacro::parse_macro2(&tt, is_2021);
+                (mac, def_site_token_map)
+            }
+            None => (
+                mbe::DeclarativeMacro::from_err(
+                    mbe::ParseError::Expected("expected a token tree".into()),
+                    is_2021,
+                ),
+                Default::default(),
+            ),
+        },
+    };
+    Arc::new(DeclarativeMacroExpander { mac, def_site_token_map })
+}
+
+fn macro_expander(db: &dyn ExpandDatabase, id: MacroDefId) -> TokenExpander {
     match id.kind {
         MacroDefKind::Declarative(ast_id) => {
-            let is_2021 = db.crate_graph()[id.krate].edition >= Edition::Edition2021;
+            TokenExpander::DeclarativeMacro(db.decl_macro_expander(id.krate, ast_id))
-            let (mac, def_site_token_map) = match ast_id.to_node(db) {
-                ast::Macro::MacroRules(macro_rules) => {
-                    let arg = macro_rules
-                        .token_tree()
-                        .ok_or_else(|| mbe::ParseError::Expected("expected a token tree".into()))?;
-                    let (tt, def_site_token_map) = mbe::syntax_node_to_token_tree(arg.syntax());
-                    let mac = mbe::DeclarativeMacro::parse_macro_rules(&tt, is_2021)?;
-                    (mac, def_site_token_map)
-                }
-                ast::Macro::MacroDef(macro_def) => {
-                    let arg = macro_def
-                        .body()
-                        .ok_or_else(|| mbe::ParseError::Expected("expected a token tree".into()))?;
-                    let (tt, def_site_token_map) = mbe::syntax_node_to_token_tree(arg.syntax());
-                    let mac = mbe::DeclarativeMacro::parse_macro2(&tt, is_2021)?;
-                    (mac, def_site_token_map)
-                }
-            };
-            Ok(Arc::new(TokenExpander::DeclarativeMacro { mac, def_site_token_map }))
         }
-        MacroDefKind::BuiltIn(expander, _) => Ok(Arc::new(TokenExpander::Builtin(expander))),
+        MacroDefKind::BuiltIn(expander, _) => TokenExpander::BuiltIn(expander),
-        MacroDefKind::BuiltInAttr(expander, _) => {
+        MacroDefKind::BuiltInAttr(expander, _) => TokenExpander::BuiltInAttr(expander),
-            Ok(Arc::new(TokenExpander::BuiltinAttr(expander)))
+        MacroDefKind::BuiltInDerive(expander, _) => TokenExpander::BuiltInDerive(expander),
-        }
+        MacroDefKind::BuiltInEager(expander, ..) => TokenExpander::BuiltInEager(expander),
-        MacroDefKind::BuiltInDerive(expander, _) => {
+        MacroDefKind::ProcMacro(expander, ..) => TokenExpander::ProcMacro(expander),
-            Ok(Arc::new(TokenExpander::BuiltinDerive(expander)))
-        }
-        MacroDefKind::BuiltInEager(expander, ..) => {
-            Ok(Arc::new(TokenExpander::BuiltinEager(expander)))
-        }
-        MacroDefKind::ProcMacro(expander, ..) => Ok(Arc::new(TokenExpander::ProcMacro(expander))),
     }
 }
 
 fn macro_expand(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandResult<Arc<tt::Subtree>> {
     let _p = profile::span("macro_expand");
     let loc = db.lookup_intern_macro_call(id);
-    if let Some(EagerCallInfo { arg, arg_id: None, error }) = loc.eager.as_deref() {
+
-        // This is an input expansion for an eager macro. These are already pre-expanded
+    let ExpandResult { value: tt, mut err } = match loc.def.kind {
-        return ExpandResult { value: Arc::new(arg.0.clone()), err: error.clone() };
+        MacroDefKind::ProcMacro(..) => return db.expand_proc_macro(id),
-    }
+        MacroDefKind::BuiltInDerive(expander, ..) => {
-    let expander = match db.macro_def(loc.def) {
+            let arg = db.macro_arg_node(id).value.unwrap();
-        Ok(it) => it,
+
-        // FIXME: We should make sure to enforce a variant that invalid macro
+            let node = SyntaxNode::new_root(arg);
-        // definitions do not get expanders that could reach this call path!
+            let censor = censor_for_macro_input(&loc, &node);
-        Err(err) => {
+            let mut fixups = fixup::fixup_syntax(&node);
-            return ExpandResult {
+            fixups.replace.extend(censor.into_iter().map(|node| (node.into(), Vec::new())));
-                value: Arc::new(tt::Subtree {
+            let (tmap, _) = mbe::syntax_node_to_token_map_with_modifications(
-                    delimiter: tt::Delimiter::UNSPECIFIED,
+                &node,
-                    token_trees: vec![],
+                fixups.token_map,
-                }),
+                fixups.next_id,
-                err: Some(ExpandError::other(format!("invalid macro definition: {err}"))),
+                fixups.replace,
-            }
+                fixups.append,
+            );
+
+            // this cast is a bit sus, can we avoid losing the typedness here?
+            let adt = ast::Adt::cast(node).unwrap();
+            let mut res = expander.expand(db, id, &adt, &tmap);
+            fixup::reverse_fixups(&mut res.value, &tmap, &fixups.undo_info);
+            res
+        }
+        _ => {
+            let ValueResult { value, err } = db.macro_arg(id);
+            let Some(macro_arg) = value else {
+                return ExpandResult {
+                    value: Arc::new(tt::Subtree {
+                        delimiter: tt::Delimiter::UNSPECIFIED,
+                        token_trees: Vec::new(),
+                    }),
+                    // FIXME: We should make sure to enforce an invariant that invalid macro
+                    // calls do not reach this call path!
+                    err: Some(ExpandError::other("invalid token tree")),
+                };
+            };
+
+            let (arg, arg_tm, undo_info) = &*macro_arg;
+            let mut res = match loc.def.kind {
+                MacroDefKind::Declarative(id) => {
+                    db.decl_macro_expander(loc.def.krate, id).expand(arg.clone())
+                }
+                MacroDefKind::BuiltIn(it, _) => it.expand(db, id, &arg).map_err(Into::into),
+                // This might look a bit odd, but we do not expand the inputs to eager macros here.
+                // Eager macros inputs are expanded, well, eagerly when we collect the macro calls.
+                // That kind of expansion uses the ast id map of an eager macros input though which goes through
+                // the HirFileId machinery. As eager macro inputs are assigned a macro file id that query
+                // will end up going through here again, whereas we want to just want to inspect the raw input.
+                // As such we just return the input subtree here.
+                MacroDefKind::BuiltInEager(..) if loc.eager.is_none() => {
+                    let mut arg = arg.clone();
+                    fixup::reverse_fixups(&mut arg, arg_tm, undo_info);
+
+                    return ExpandResult {
+                        value: Arc::new(arg),
+                        err: err.map(|err| {
+                            let mut buf = String::new();
+                            for err in &**err {
+                                use std::fmt::Write;
+                                _ = write!(buf, "{}, ", err);
+                            }
+                            buf.pop();
+                            buf.pop();
+                            ExpandError::other(buf)
+                        }),
+                    };
+                }
+                MacroDefKind::BuiltInEager(it, _) => it.expand(db, id, &arg).map_err(Into::into),
+                MacroDefKind::BuiltInAttr(it, _) => it.expand(db, id, &arg),
+                _ => unreachable!(),
+            };
+            fixup::reverse_fixups(&mut res.value, arg_tm, undo_info);
+            res
         }
     };
-    let Some(macro_arg) = db.macro_arg(id) else {
-        return ExpandResult {
-            value: Arc::new(
-                tt::Subtree {
-                    delimiter: tt::Delimiter::UNSPECIFIED,
-                    token_trees: Vec::new(),
-                },
-            ),
-            // FIXME: We should make sure to enforce a variant that invalid macro
-            // calls do not reach this call path!
-            err: Some(ExpandError::other(
-                "invalid token tree"
-            )),
-        };
-    };
-    let (arg_tt, arg_tm, undo_info) = &*macro_arg;
-    let ExpandResult { value: mut tt, mut err } = expander.expand(db, id, arg_tt);
 
     if let Some(EagerCallInfo { error, .. }) = loc.eager.as_deref() {
         // FIXME: We should report both errors!
@@ -483,48 +616,29 @@ fn macro_expand(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandResult<Arc<tt
     }
 
     // Set a hard limit for the expanded tt
-    let count = tt.count();
+    if let Err(value) = check_tt_count(&tt) {
-    if TOKEN_LIMIT.check(count).is_err() {
+        return value;
-        return ExpandResult {
-            value: Arc::new(tt::Subtree {
-                delimiter: tt::Delimiter::UNSPECIFIED,
-                token_trees: vec![],
-            }),
-            err: Some(ExpandError::other(format!(
-                "macro invocation exceeds token limit: produced {} tokens, limit is {}",
-                count,
-                TOKEN_LIMIT.inner(),
-            ))),
-        };
     }
 
-    fixup::reverse_fixups(&mut tt, arg_tm, undo_info);
-
     ExpandResult { value: Arc::new(tt), err }
 }
 
-fn parse_macro_expansion_error(
+fn expand_proc_macro(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandResult<Arc<tt::Subtree>> {
-    db: &dyn ExpandDatabase,
-    macro_call_id: MacroCallId,
-) -> ExpandResult<Box<[SyntaxError]>> {
-    db.parse_macro_expansion(MacroFile { macro_call_id })
-        .map(|it| it.0.errors().to_vec().into_boxed_slice())
-}
-
-fn expand_proc_macro(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandResult<tt::Subtree> {
     let loc = db.lookup_intern_macro_call(id);
-    let Some(macro_arg) = db.macro_arg(id) else {
+    let Some(macro_arg) = db.macro_arg(id).value else {
         return ExpandResult {
-            value: tt::Subtree {
+            value: Arc::new(tt::Subtree {
                 delimiter: tt::Delimiter::UNSPECIFIED,
                 token_trees: Vec::new(),
-            },
+            }),
-            err: Some(ExpandError::other(
+            // FIXME: We should make sure to enforce an invariant that invalid macro
-                "invalid token tree"
+            // calls do not reach this call path!
-            )),
+            err: Some(ExpandError::other("invalid token tree")),
         };
     };
 
+    let (arg_tt, arg_tm, undo_info) = &*macro_arg;
+
     let expander = match loc.def.kind {
         MacroDefKind::ProcMacro(expander, ..) => expander,
         _ => unreachable!(),
@@ -533,13 +647,23 @@ fn expand_proc_macro(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandResult<t
     let attr_arg = match &loc.kind {
         MacroCallKind::Attr { attr_args, .. } => {
             let mut attr_args = attr_args.0.clone();
-            mbe::Shift::new(&macro_arg.0).shift_all(&mut attr_args);
+            mbe::Shift::new(arg_tt).shift_all(&mut attr_args);
             Some(attr_args)
         }
         _ => None,
     };
 
-    expander.expand(db, loc.def.krate, loc.krate, &macro_arg.0, attr_arg.as_ref())
+    let ExpandResult { value: mut tt, err } =
+        expander.expand(db, loc.def.krate, loc.krate, arg_tt, attr_arg.as_ref());
+
+    // Set a hard limit for the expanded tt
+    if let Err(value) = check_tt_count(&tt) {
+        return value;
+    }
+
+    fixup::reverse_fixups(&mut tt, arg_tm, undo_info);
+
+    ExpandResult { value: Arc::new(tt), err }
 }
 
 fn hygiene_frame(db: &dyn ExpandDatabase, file_id: HirFileId) -> Arc<HygieneFrame> {
@@ -563,3 +687,22 @@ fn token_tree_to_syntax_node(
     };
     mbe::token_tree_to_syntax_node(tt, entry_point)
 }
+
+fn check_tt_count(tt: &tt::Subtree) -> Result<(), ExpandResult<Arc<tt::Subtree>>> {
+    let count = tt.count();
+    if TOKEN_LIMIT.check(count).is_err() {
+        Err(ExpandResult {
+            value: Arc::new(tt::Subtree {
+                delimiter: tt::Delimiter::UNSPECIFIED,
+                token_trees: vec![],
+            }),
+            err: Some(ExpandError::other(format!(
+                "macro invocation exceeds token limit: produced {} tokens, limit is {}",
+                count,
+                TOKEN_LIMIT.inner(),
+            ))),
+        })
+    } else {
+        Ok(())
+    }
+}

crates/hir-expand/src/eager.rs

@@ -19,7 +19,8 @@
 //!
 //! See the full discussion : <https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Eager.20expansion.20of.20built-in.20macros>
 use base_db::CrateId;
-use syntax::{ted, Parse, SyntaxNode};
+use rustc_hash::FxHashMap;
+use syntax::{ted, Parse, SyntaxNode, TextRange, TextSize, WalkEvent};
 use triomphe::Arc;
 
 use crate::{
@@ -38,19 +39,8 @@ pub fn expand_eager_macro_input(
     def: MacroDefId,
     resolver: &dyn Fn(ModPath) -> Option<MacroDefId>,
 ) -> Result<ExpandResult<Option<MacroCallId>>, UnresolvedMacro> {
-    assert!(matches!(def.kind, MacroDefKind::BuiltInEager(..)));
-    let token_tree = macro_call.value.token_tree();
-
-    let Some(token_tree) = token_tree else {
-        return Ok(ExpandResult { value: None, err:
-            Some(ExpandError::other(
-                "invalid token tree"
-            )),
-        });
-    };
-    let (parsed_args, arg_token_map) = mbe::syntax_node_to_token_tree(token_tree.syntax());
-
     let ast_map = db.ast_id_map(macro_call.file_id);
+    // the expansion which the ast id map is built upon has no whitespace, so the offsets are wrong as macro_call is from the token tree that has whitespace!
     let call_id = InFile::new(macro_call.file_id, ast_map.ast_id(&macro_call.value));
     let expand_to = ExpandTo::from_call_site(&macro_call.value);
 
@@ -61,41 +51,69 @@ pub fn expand_eager_macro_input(
     let arg_id = db.intern_macro_call(MacroCallLoc {
         def,
         krate,
-        eager: Some(Box::new(EagerCallInfo {
+        eager: None,
-            arg: Arc::new((parsed_args, arg_token_map)),
-            arg_id: None,
-            error: None,
-        })),
         kind: MacroCallKind::FnLike { ast_id: call_id, expand_to: ExpandTo::Expr },
     });
-    let arg_as_expr = match db.macro_arg_text(arg_id) {
+    let ExpandResult { value: (arg_exp, arg_exp_map), err: parse_err } =
-        Some(it) => it,
+        db.parse_macro_expansion(arg_id.as_macro_file());
-        None => {
+    // we need this map here as the expansion of the eager input fake file loses whitespace ...
-            return Ok(ExpandResult {
+    let mut ws_mapping = FxHashMap::default();
-                value: None,
+    if let Some((_, tm, _)) = db.macro_arg(arg_id).value.as_deref() {
-                err: Some(ExpandError::other("invalid token tree")),
+        ws_mapping.extend(tm.entries().filter_map(|(id, range)| {
-            })
+            Some((arg_exp_map.first_range_by_token(id, syntax::SyntaxKind::TOMBSTONE)?, range))
+        }));
+    }
+
+    let ExpandResult { value: expanded_eager_input, err } = {
+        eager_macro_recur(
+            db,
+            &Hygiene::new(db, macro_call.file_id),
+            InFile::new(arg_id.as_file(), arg_exp.syntax_node()),
+            krate,
+            resolver,
+        )?
+    };
+    let err = parse_err.or(err);
+
+    let Some((expanded_eager_input, mapping)) = expanded_eager_input else {
+        return Ok(ExpandResult { value: None, err });
+    };
+
+    let og_tmap = mbe::syntax_node_to_token_map(
+        macro_call.value.token_tree().expect("macro_arg_text succeeded").syntax(),
+    );
+
+    let (mut subtree, expanded_eager_input_token_map) =
+        mbe::syntax_node_to_token_tree(&expanded_eager_input);
+
+    // The tokenmap and ids of subtree point into the expanded syntax node, but that is inaccessible from the outside
+    // so we need to remap them to the original input of the eager macro.
+    subtree.visit_ids(&|id| {
+        // Note: we discard all token ids of braces and the like here, but that's not too bad and only a temporary fix
+
+        if let Some(range) =
+            expanded_eager_input_token_map.first_range_by_token(id, syntax::SyntaxKind::TOMBSTONE)
+        {
+            // remap from expanded eager input to eager input expansion
+            if let Some(og_range) = mapping.get(&range) {
+                // remap from eager input expansion to original eager input
+                if let Some(&og_range) = ws_mapping.get(og_range) {
+                    if let Some(og_token) = og_tmap.token_by_range(og_range) {
+                        return og_token;
+                    }
+                }
+            }
         }
-    };
+        tt::TokenId::UNSPECIFIED
-    let ExpandResult { value: expanded_eager_input, err } = eager_macro_recur(
+    });
-        db,
-        &Hygiene::new(db, macro_call.file_id),
-        InFile::new(arg_id.as_file(), SyntaxNode::new_root(arg_as_expr)),
-        krate,
-        resolver,
-    )?;
-    let Some(expanded_eager_input) = expanded_eager_input else {
-        return Ok(ExpandResult { value: None, err })
-    };
-    let (mut subtree, token_map) = mbe::syntax_node_to_token_tree(&expanded_eager_input);
     subtree.delimiter = crate::tt::Delimiter::unspecified();
 
     let loc = MacroCallLoc {
         def,
         krate,
         eager: Some(Box::new(EagerCallInfo {
-            arg: Arc::new((subtree, token_map)),
+            arg: Arc::new((subtree, og_tmap)),
-            arg_id: Some(arg_id),
+            arg_id,
             error: err.clone(),
         })),
         kind: MacroCallKind::FnLike { ast_id: call_id, expand_to },
@@ -109,19 +127,16 @@ fn lazy_expand(
     def: &MacroDefId,
     macro_call: InFile<ast::MacroCall>,
     krate: CrateId,
-) -> ExpandResult<InFile<Parse<SyntaxNode>>> {
+) -> ExpandResult<(InFile<Parse<SyntaxNode>>, Arc<mbe::TokenMap>)> {
     let ast_id = db.ast_id_map(macro_call.file_id).ast_id(&macro_call.value);
 
     let expand_to = ExpandTo::from_call_site(&macro_call.value);
-    let id = def.as_lazy_macro(
+    let ast_id = macro_call.with_value(ast_id);
-        db,
+    let id = def.as_lazy_macro(db, krate, MacroCallKind::FnLike { ast_id, expand_to });
-        krate,
-        MacroCallKind::FnLike { ast_id: macro_call.with_value(ast_id), expand_to },
-    );
-
     let macro_file = id.as_macro_file();
 
-    db.parse_macro_expansion(macro_file).map(|parse| InFile::new(macro_file.into(), parse.0))
+    db.parse_macro_expansion(macro_file)
+        .map(|parse| (InFile::new(macro_file.into(), parse.0), parse.1))
 }
 
 fn eager_macro_recur(
@@ -130,18 +145,43 @@ fn eager_macro_recur(
     curr: InFile<SyntaxNode>,
     krate: CrateId,
     macro_resolver: &dyn Fn(ModPath) -> Option<MacroDefId>,
-) -> Result<ExpandResult<Option<SyntaxNode>>, UnresolvedMacro> {
+) -> Result<ExpandResult<Option<(SyntaxNode, FxHashMap<TextRange, TextRange>)>>, UnresolvedMacro> {
     let original = curr.value.clone_for_update();
+    let mut mapping = FxHashMap::default();
 
-    let children = original.descendants().filter_map(ast::MacroCall::cast);
     let mut replacements = Vec::new();
 
     // Note: We only report a single error inside of eager expansions
     let mut error = None;
+    let mut offset = 0i32;
+    let apply_offset = |it: TextSize, offset: i32| {
+        TextSize::from(u32::try_from(offset + u32::from(it) as i32).unwrap_or_default())
+    };
+    let mut children = original.preorder_with_tokens();
 
     // Collect replacement
-    for child in children {
+    while let Some(child) = children.next() {
-        let def = match child.path().and_then(|path| ModPath::from_src(db, path, hygiene)) {
+        let WalkEvent::Enter(child) = child else { continue };
+        let call = match child {
+            syntax::NodeOrToken::Node(node) => match ast::MacroCall::cast(node) {
+                Some(it) => {
+                    children.skip_subtree();
+                    it
+                }
+                None => continue,
+            },
+            syntax::NodeOrToken::Token(t) => {
+                mapping.insert(
+                    TextRange::new(
+                        apply_offset(t.text_range().start(), offset),
+                        apply_offset(t.text_range().end(), offset),
+                    ),
+                    t.text_range(),
+                );
+                continue;
+            }
+        };
+        let def = match call.path().and_then(|path| ModPath::from_src(db, path, hygiene)) {
             Some(path) => macro_resolver(path.clone()).ok_or(UnresolvedMacro { path })?,
             None => {
                 error = Some(ExpandError::other("malformed macro invocation"));
@@ -153,7 +193,7 @@ fn eager_macro_recur(
                 let ExpandResult { value, err } = match expand_eager_macro_input(
                     db,
                     krate,
-                    curr.with_value(child.clone()),
+                    curr.with_value(call.clone()),
                     def,
                     macro_resolver,
                 ) {
@@ -161,9 +201,22 @@ fn eager_macro_recur(
                     Err(err) => return Err(err),
                 };
                 match value {
-                    Some(call) => {
+                    Some(call_id) => {
                         let ExpandResult { value, err: err2 } =
-                            db.parse_macro_expansion(call.as_macro_file());
+                            db.parse_macro_expansion(call_id.as_macro_file());
+
+                        let call_tt_start =
+                            call.token_tree().unwrap().syntax().text_range().start();
+                        let call_start = apply_offset(call.syntax().text_range().start(), offset);
+                        if let Some((_, arg_map, _)) = db.macro_arg(call_id).value.as_deref() {
+                            mapping.extend(arg_map.entries().filter_map(|(tid, range)| {
+                                value
+                                    .1
+                                    .first_range_by_token(tid, syntax::SyntaxKind::TOMBSTONE)
+                                    .map(|r| (r + call_start, range + call_tt_start))
+                            }));
+                        };
+
                         ExpandResult {
                             value: Some(value.0.syntax_node().clone_for_update()),
                             err: err.or(err2),
@@ -177,36 +230,61 @@ fn eager_macro_recur(
             | MacroDefKind::BuiltInAttr(..)
             | MacroDefKind::BuiltInDerive(..)
             | MacroDefKind::ProcMacro(..) => {
-                let ExpandResult { value, err } =
+                let ExpandResult { value: (parse, tm), err } =
-                    lazy_expand(db, &def, curr.with_value(child.clone()), krate);
+                    lazy_expand(db, &def, curr.with_value(call.clone()), krate);
+                let decl_mac = if let MacroDefKind::Declarative(ast_id) = def.kind {
+                    Some(db.decl_macro_expander(def.krate, ast_id))
+                } else {
+                    None
+                };
 
                 // replace macro inside
-                let hygiene = Hygiene::new(db, value.file_id);
+                let hygiene = Hygiene::new(db, parse.file_id);
                 let ExpandResult { value, err: error } = eager_macro_recur(
                     db,
                     &hygiene,
                     // FIXME: We discard parse errors here
-                    value.map(|it| it.syntax_node()),
+                    parse.as_ref().map(|it| it.syntax_node()),
                     krate,
                     macro_resolver,
                 )?;
                 let err = err.or(error);
-                ExpandResult { value, err }
+
+                let call_tt_start = call.token_tree().unwrap().syntax().text_range().start();
+                let call_start = apply_offset(call.syntax().text_range().start(), offset);
+                if let Some((_tt, arg_map, _)) = parse
+                    .file_id
+                    .macro_file()
+                    .and_then(|id| db.macro_arg(id.macro_call_id).value)
+                    .as_deref()
+                {
+                    mapping.extend(arg_map.entries().filter_map(|(tid, range)| {
+                        tm.first_range_by_token(
+                            decl_mac.as_ref().map(|it| it.map_id_down(tid)).unwrap_or(tid),
+                            syntax::SyntaxKind::TOMBSTONE,
+                        )
+                        .map(|r| (r + call_start, range + call_tt_start))
+                    }));
+                };
+                // FIXME: Do we need to re-use _m here?
+                ExpandResult { value: value.map(|(n, _m)| n), err }
             }
         };
         if err.is_some() {
             error = err;
         }
         // check if the whole original syntax is replaced
-        if child.syntax() == &original {
+        if call.syntax() == &original {
-            return Ok(ExpandResult { value, err: error });
+            return Ok(ExpandResult { value: value.zip(Some(mapping)), err: error });
         }
 
         if let Some(insert) = value {
-            replacements.push((child, insert));
+            offset += u32::from(insert.text_range().len()) as i32
+                - u32::from(call.syntax().text_range().len()) as i32;
+            replacements.push((call, insert));
         }
     }
 
     replacements.into_iter().rev().for_each(|(old, new)| ted::replace(old.syntax(), new));
-    Ok(ExpandResult { value: Some(original), err: error })
+    Ok(ExpandResult { value: Some((original, mapping)), err: error })
 }

crates/hir-expand/src/fixup.rs

@@ -26,7 +26,7 @@ pub(crate) struct SyntaxFixups {
 /// This is the information needed to reverse the fixups.
 #[derive(Debug, Default, PartialEq, Eq)]
 pub struct SyntaxFixupUndoInfo {
-    original: Vec<Subtree>,
+    original: Box<[Subtree]>,
 }
 
 const EMPTY_ID: SyntheticTokenId = SyntheticTokenId(!0);
@@ -272,7 +272,7 @@ pub(crate) fn fixup_syntax(node: &SyntaxNode) -> SyntaxFixups {
         replace,
         token_map,
         next_id,
-        undo_info: SyntaxFixupUndoInfo { original },
+        undo_info: SyntaxFixupUndoInfo { original: original.into_boxed_slice() },
     }
 }
 
@@ -472,13 +472,13 @@ fn foo () {match __ra_fixup {}}
         check(
             r#"
 fn foo() {
-    match x {
+    match it {
 
     }
 }
 "#,
             expect![[r#"
-fn foo () {match x {}}
+fn foo () {match it {}}
 "#]],
         )
     }
@@ -547,11 +547,11 @@ fn foo () {a . __ra_fixup ; bar () ;}
         check(
             r#"
 fn foo() {
-    let x = a
+    let it = a
 }
 "#,
             expect![[r#"
-fn foo () {let x = a ;}
+fn foo () {let it = a ;}
 "#]],
         )
     }
@@ -561,11 +561,11 @@ fn foo () {let x = a ;}
         check(
             r#"
 fn foo() {
-    let x = a.
+    let it = a.
 }
 "#,
             expect![[r#"
-fn foo () {let x = a . __ra_fixup ;}
+fn foo () {let it = a . __ra_fixup ;}
 "#]],
         )
     }

crates/hir-expand/src/hygiene.rs

@@ -126,7 +126,7 @@ struct HygieneInfo {
     /// The start offset of the `macro_rules!` arguments or attribute input.
     attr_input_or_mac_def_start: Option<InFile<TextSize>>,
 
-    macro_def: Arc<TokenExpander>,
+    macro_def: TokenExpander,
     macro_arg: Arc<(crate::tt::Subtree, mbe::TokenMap, fixup::SyntaxFixupUndoInfo)>,
     macro_arg_shift: mbe::Shift,
     exp_map: Arc<mbe::TokenMap>,
@@ -149,19 +149,15 @@ impl HygieneInfo {
                     token_id = unshifted;
                     (&attr_args.1, self.attr_input_or_mac_def_start?)
                 }
-                None => (
+                None => (&self.macro_arg.1, loc.kind.arg(db)?.map(|it| it.text_range().start())),
-                    &self.macro_arg.1,
-                    InFile::new(loc.kind.file_id(), loc.kind.arg(db)?.text_range().start()),
-                ),
             },
             _ => match origin {
-                mbe::Origin::Call => (
+                mbe::Origin::Call => {
-                    &self.macro_arg.1,
+                    (&self.macro_arg.1, loc.kind.arg(db)?.map(|it| it.text_range().start()))
-                    InFile::new(loc.kind.file_id(), loc.kind.arg(db)?.text_range().start()),
+                }
-                ),
+                mbe::Origin::Def => match (&self.macro_def, &self.attr_input_or_mac_def_start) {
-                mbe::Origin::Def => match (&*self.macro_def, &self.attr_input_or_mac_def_start) {
+                    (TokenExpander::DeclarativeMacro(expander), Some(tt)) => {
-                    (TokenExpander::DeclarativeMacro { def_site_token_map, .. }, Some(tt)) => {
+                        (&expander.def_site_token_map, *tt)
-                        (def_site_token_map, *tt)
                     }
                     _ => panic!("`Origin::Def` used with non-`macro_rules!` macro"),
                 },
@@ -198,9 +194,9 @@ fn make_hygiene_info(
         _ => None,
     });
 
-    let macro_def = db.macro_def(loc.def).ok()?;
+    let macro_def = db.macro_expander(loc.def);
     let (_, exp_map) = db.parse_macro_expansion(macro_file).value;
-    let macro_arg = db.macro_arg(macro_file.macro_call_id).unwrap_or_else(|| {
+    let macro_arg = db.macro_arg(macro_file.macro_call_id).value.unwrap_or_else(|| {
         Arc::new((
             tt::Subtree { delimiter: tt::Delimiter::UNSPECIFIED, token_trees: Vec::new() },
             Default::default(),

crates/hir-expand/src/lib.rs

@@ -37,11 +37,11 @@ use either::Either;
 use syntax::{
     algo::{self, skip_trivia_token},
     ast::{self, AstNode, HasDocComments},
-    Direction, SyntaxNode, SyntaxToken,
+    AstPtr, Direction, SyntaxNode, SyntaxNodePtr, SyntaxToken,
 };
 
 use crate::{
-    ast_id_map::FileAstId,
+    ast_id_map::{AstIdNode, ErasedFileAstId, FileAstId},
     attrs::AttrId,
     builtin_attr_macro::BuiltinAttrExpander,
     builtin_derive_macro::BuiltinDeriveExpander,
@@ -127,7 +127,8 @@ impl_intern_key!(MacroCallId);
 pub struct MacroCallLoc {
     pub def: MacroDefId,
     pub(crate) krate: CrateId,
-    /// Some if `def` is a builtin eager macro.
+    /// Some if this is a macro call for an eager macro. Note that this is `None`
+    /// for the eager input macro file.
     eager: Option<Box<EagerCallInfo>>,
     pub kind: MacroCallKind,
 }
@@ -152,11 +153,10 @@ pub enum MacroDefKind {
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 struct EagerCallInfo {
-    /// NOTE: This can be *either* the expansion result, *or* the argument to the eager macro!
+    /// The expanded argument of the eager macro.
     arg: Arc<(tt::Subtree, TokenMap)>,
-    /// call id of the eager macro's input file. If this is none, macro call containing this call info
+    /// Call id of the eager macro's input file (this is the macro file for its fully expanded input).
-    /// is an eager macro's input, otherwise it is its output.
+    arg_id: MacroCallId,
-    arg_id: Option<MacroCallId>,
     error: Option<ExpandError>,
 }
 
@@ -221,11 +221,7 @@ impl HirFileId {
                 HirFileIdRepr::FileId(id) => break id,
                 HirFileIdRepr::MacroFile(MacroFile { macro_call_id }) => {
                     let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_call_id);
-                    let is_include_expansion = loc.def.is_include()
+                    let is_include_expansion = loc.def.is_include() && loc.eager.is_some();
-                        && matches!(
-                            loc.eager.as_deref(),
-                            Some(EagerCallInfo { arg_id: Some(_), .. })
-                        );
                     file_id = match is_include_expansion.then(|| db.include_expand(macro_call_id)) {
                         Some(Ok((_, file))) => file.into(),
                         _ => loc.kind.file_id(),
@@ -270,57 +266,13 @@ impl HirFileId {
     /// Return expansion information if it is a macro-expansion file
     pub fn expansion_info(self, db: &dyn db::ExpandDatabase) -> Option<ExpansionInfo> {
         let macro_file = self.macro_file()?;
-        let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
+        ExpansionInfo::new(db, macro_file)
-
-        let arg_tt = loc.kind.arg(db)?;
-
-        let macro_def = db.macro_def(loc.def).ok()?;
-        let (parse, exp_map) = db.parse_macro_expansion(macro_file).value;
-        let macro_arg = db.macro_arg(macro_file.macro_call_id).unwrap_or_else(|| {
-            Arc::new((
-                tt::Subtree { delimiter: tt::Delimiter::UNSPECIFIED, token_trees: Vec::new() },
-                Default::default(),
-                Default::default(),
-            ))
-        });
-
-        let def = loc.def.ast_id().left().and_then(|id| {
-            let def_tt = match id.to_node(db) {
-                ast::Macro::MacroRules(mac) => mac.token_tree()?,
-                ast::Macro::MacroDef(_) if matches!(*macro_def, TokenExpander::BuiltinAttr(_)) => {
-                    return None
-                }
-                ast::Macro::MacroDef(mac) => mac.body()?,
-            };
-            Some(InFile::new(id.file_id, def_tt))
-        });
-        let attr_input_or_mac_def = def.or_else(|| match loc.kind {
-            MacroCallKind::Attr { ast_id, invoc_attr_index, .. } => {
-                // FIXME: handle `cfg_attr`
-                let tt = ast_id
-                    .to_node(db)
-                    .doc_comments_and_attrs()
-                    .nth(invoc_attr_index.ast_index())
-                    .and_then(Either::left)?
-                    .token_tree()?;
-                Some(InFile::new(ast_id.file_id, tt))
-            }
-            _ => None,
-        });
-
-        Some(ExpansionInfo {
-            expanded: InFile::new(self, parse.syntax_node()),
-            arg: InFile::new(loc.kind.file_id(), arg_tt),
-            attr_input_or_mac_def,
-            macro_arg_shift: mbe::Shift::new(&macro_arg.0),
-            macro_arg,
-            macro_def,
-            exp_map,
-        })
     }
 
-    /// Indicate it is macro file generated for builtin derive
+    pub fn as_builtin_derive_attr_node(
-    pub fn is_builtin_derive(&self, db: &dyn db::ExpandDatabase) -> Option<InFile<ast::Attr>> {
+        &self,
+        db: &dyn db::ExpandDatabase,
+    ) -> Option<InFile<ast::Attr>> {
         let macro_file = self.macro_file()?;
         let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
         let attr = match loc.def.kind {
@@ -333,8 +285,22 @@ impl HirFileId {
     pub fn is_custom_derive(&self, db: &dyn db::ExpandDatabase) -> bool {
         match self.macro_file() {
             Some(macro_file) => {
-                let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
+                matches!(
-                matches!(loc.def.kind, MacroDefKind::ProcMacro(_, ProcMacroKind::CustomDerive, _))
+                    db.lookup_intern_macro_call(macro_file.macro_call_id).def.kind,
+                    MacroDefKind::ProcMacro(_, ProcMacroKind::CustomDerive, _)
+                )
+            }
+            None => false,
+        }
+    }
+
+    pub fn is_builtin_derive(&self, db: &dyn db::ExpandDatabase) -> bool {
+        match self.macro_file() {
+            Some(macro_file) => {
+                matches!(
+                    db.lookup_intern_macro_call(macro_file.macro_call_id).def.kind,
+                    MacroDefKind::BuiltInDerive(..)
+                )
             }
             None => false,
         }
@@ -344,8 +310,7 @@ impl HirFileId {
     pub fn is_include_macro(&self, db: &dyn db::ExpandDatabase) -> bool {
         match self.macro_file() {
             Some(macro_file) => {
-                let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
+                db.lookup_intern_macro_call(macro_file.macro_call_id).def.is_include()
-                loc.def.is_include()
             }
             _ => false,
         }
@@ -355,7 +320,7 @@ impl HirFileId {
         match self.macro_file() {
             Some(macro_file) => {
                 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
-                matches!(loc.eager.as_deref(), Some(EagerCallInfo { .. }))
+                matches!(loc.def.kind, MacroDefKind::BuiltInEager(..))
             }
             _ => false,
         }
@@ -536,9 +501,9 @@ impl MacroCallKind {
         };
 
         let range = match kind {
-            MacroCallKind::FnLike { ast_id, .. } => ast_id.to_node(db).syntax().text_range(),
+            MacroCallKind::FnLike { ast_id, .. } => ast_id.to_ptr(db).text_range(),
-            MacroCallKind::Derive { ast_id, .. } => ast_id.to_node(db).syntax().text_range(),
+            MacroCallKind::Derive { ast_id, .. } => ast_id.to_ptr(db).text_range(),
-            MacroCallKind::Attr { ast_id, .. } => ast_id.to_node(db).syntax().text_range(),
+            MacroCallKind::Attr { ast_id, .. } => ast_id.to_ptr(db).text_range(),
         };
 
         FileRange { range, file_id }
@@ -588,13 +553,18 @@ impl MacroCallKind {
         FileRange { range, file_id }
     }
 
-    fn arg(&self, db: &dyn db::ExpandDatabase) -> Option<SyntaxNode> {
+    fn arg(&self, db: &dyn db::ExpandDatabase) -> Option<InFile<SyntaxNode>> {
         match self {
-            MacroCallKind::FnLike { ast_id, .. } => {
+            MacroCallKind::FnLike { ast_id, .. } => ast_id
-                Some(ast_id.to_node(db).token_tree()?.syntax().clone())
+                .to_in_file_node(db)
+                .map(|it| Some(it.token_tree()?.syntax().clone()))
+                .transpose(),
+            MacroCallKind::Derive { ast_id, .. } => {
+                Some(ast_id.to_in_file_node(db).syntax().cloned())
+            }
+            MacroCallKind::Attr { ast_id, .. } => {
+                Some(ast_id.to_in_file_node(db).syntax().cloned())
             }
-            MacroCallKind::Derive { ast_id, .. } => Some(ast_id.to_node(db).syntax().clone()),
-            MacroCallKind::Attr { ast_id, .. } => Some(ast_id.to_node(db).syntax().clone()),
         }
     }
 }
@@ -612,13 +582,13 @@ impl MacroCallId {
 /// ExpansionInfo mainly describes how to map text range between src and expanded macro
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ExpansionInfo {
-    expanded: InFile<SyntaxNode>,
+    expanded: InMacroFile<SyntaxNode>,
     /// The argument TokenTree or item for attributes
     arg: InFile<SyntaxNode>,
     /// The `macro_rules!` or attribute input.
     attr_input_or_mac_def: Option<InFile<ast::TokenTree>>,
 
-    macro_def: Arc<TokenExpander>,
+    macro_def: TokenExpander,
     macro_arg: Arc<(tt::Subtree, mbe::TokenMap, fixup::SyntaxFixupUndoInfo)>,
     /// A shift built from `macro_arg`'s subtree, relevant for attributes as the item is the macro arg
     /// and as such we need to shift tokens if they are part of an attributes input instead of their item.
@@ -628,7 +598,7 @@ pub struct ExpansionInfo {
 
 impl ExpansionInfo {
     pub fn expanded(&self) -> InFile<SyntaxNode> {
-        self.expanded.clone()
+        self.expanded.clone().into()
     }
 
     pub fn call_node(&self) -> Option<InFile<SyntaxNode>> {
@@ -659,7 +629,7 @@ impl ExpansionInfo {
         let token_id_in_attr_input = if let Some(item) = item {
             // check if we are mapping down in an attribute input
             // this is a special case as attributes can have two inputs
-            let call_id = self.expanded.file_id.macro_file()?.macro_call_id;
+            let call_id = self.expanded.file_id.macro_call_id;
             let loc = db.lookup_intern_macro_call(call_id);
 
             let token_range = token.value.text_range();
@@ -705,7 +675,7 @@ impl ExpansionInfo {
                 let relative_range =
                     token.value.text_range().checked_sub(self.arg.value.text_range().start())?;
                 let token_id = self.macro_arg.1.token_by_range(relative_range)?;
-                // conditionally shift the id by a declaratives macro definition
+                // conditionally shift the id by a declarative macro definition
                 self.macro_def.map_id_down(token_id)
             }
         };
@@ -715,7 +685,7 @@ impl ExpansionInfo {
             .ranges_by_token(token_id, token.value.kind())
             .flat_map(move |range| self.expanded.value.covering_element(range).into_token());
 
-        Some(tokens.map(move |token| self.expanded.with_value(token)))
+        Some(tokens.map(move |token| InFile::new(self.expanded.file_id.into(), token)))
     }
 
     /// Map a token up out of the expansion it resides in into the arguments of the macro call of the expansion.
@@ -724,18 +694,17 @@ impl ExpansionInfo {
         db: &dyn db::ExpandDatabase,
         token: InFile<&SyntaxToken>,
     ) -> Option<(InFile<SyntaxToken>, Origin)> {
+        assert_eq!(token.file_id, self.expanded.file_id.into());
         // Fetch the id through its text range,
         let token_id = self.exp_map.token_by_range(token.value.text_range())?;
         // conditionally unshifting the id to accommodate for macro-rules def site
         let (mut token_id, origin) = self.macro_def.map_id_up(token_id);
 
-        let call_id = self.expanded.file_id.macro_file()?.macro_call_id;
+        let call_id = self.expanded.file_id.macro_call_id;
         let loc = db.lookup_intern_macro_call(call_id);
 
         // Special case: map tokens from `include!` expansions to the included file
-        if loc.def.is_include()
+        if loc.def.is_include() {
-            && matches!(loc.eager.as_deref(), Some(EagerCallInfo { arg_id: Some(_), .. }))
-        {
             if let Ok((tt_and_map, file_id)) = db.include_expand(call_id) {
                 let range = tt_and_map.1.first_range_by_token(token_id, token.value.kind())?;
                 let source = db.parse(file_id);
@@ -765,9 +734,9 @@ impl ExpansionInfo {
             }
             _ => match origin {
                 mbe::Origin::Call => (&self.macro_arg.1, self.arg.clone()),
-                mbe::Origin::Def => match (&*self.macro_def, &self.attr_input_or_mac_def) {
+                mbe::Origin::Def => match (&self.macro_def, &self.attr_input_or_mac_def) {
-                    (TokenExpander::DeclarativeMacro { def_site_token_map, .. }, Some(tt)) => {
+                    (TokenExpander::DeclarativeMacro(expander), Some(tt)) => {
-                        (def_site_token_map, tt.syntax().cloned())
+                        (&expander.def_site_token_map, tt.syntax().cloned())
                     }
                     _ => panic!("`Origin::Def` used with non-`macro_rules!` macro"),
                 },
@@ -779,6 +748,58 @@ impl ExpansionInfo {
             tt.value.covering_element(range + tt.value.text_range().start()).into_token()?;
         Some((tt.with_value(token), origin))
     }
+
+    fn new(db: &dyn db::ExpandDatabase, macro_file: MacroFile) -> Option<ExpansionInfo> {
+        let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
+
+        let arg_tt = loc.kind.arg(db)?;
+
+        let macro_def = db.macro_expander(loc.def);
+        let (parse, exp_map) = db.parse_macro_expansion(macro_file).value;
+        let expanded = InMacroFile { file_id: macro_file, value: parse.syntax_node() };
+
+        let macro_arg = db.macro_arg(macro_file.macro_call_id).value.unwrap_or_else(|| {
+            Arc::new((
+                tt::Subtree { delimiter: tt::Delimiter::UNSPECIFIED, token_trees: Vec::new() },
+                Default::default(),
+                Default::default(),
+            ))
+        });
+
+        let def = loc.def.ast_id().left().and_then(|id| {
+            let def_tt = match id.to_node(db) {
+                ast::Macro::MacroRules(mac) => mac.token_tree()?,
+                ast::Macro::MacroDef(_) if matches!(macro_def, TokenExpander::BuiltInAttr(_)) => {
+                    return None
+                }
+                ast::Macro::MacroDef(mac) => mac.body()?,
+            };
+            Some(InFile::new(id.file_id, def_tt))
+        });
+        let attr_input_or_mac_def = def.or_else(|| match loc.kind {
+            MacroCallKind::Attr { ast_id, invoc_attr_index, .. } => {
+                // FIXME: handle `cfg_attr`
+                let tt = ast_id
+                    .to_node(db)
+                    .doc_comments_and_attrs()
+                    .nth(invoc_attr_index.ast_index())
+                    .and_then(Either::left)?
+                    .token_tree()?;
+                Some(InFile::new(ast_id.file_id, tt))
+            }
+            _ => None,
+        });
+
+        Some(ExpansionInfo {
+            expanded,
+            arg: arg_tt,
+            attr_input_or_mac_def,
+            macro_arg_shift: mbe::Shift::new(&macro_arg.0),
+            macro_arg,
+            macro_def,
+            exp_map,
+        })
+    }
 }
 
 /// `AstId` points to an AST node in any file.
@@ -786,10 +807,26 @@ impl ExpansionInfo {
 /// It is stable across reparses, and can be used as salsa key/value.
 pub type AstId<N> = InFile<FileAstId<N>>;
 
-impl<N: AstNode> AstId<N> {
+impl<N: AstIdNode> AstId<N> {
     pub fn to_node(&self, db: &dyn db::ExpandDatabase) -> N {
-        let root = db.parse_or_expand(self.file_id);
+        self.to_ptr(db).to_node(&db.parse_or_expand(self.file_id))
-        db.ast_id_map(self.file_id).get(self.value).to_node(&root)
+    }
+    pub fn to_in_file_node(&self, db: &dyn db::ExpandDatabase) -> InFile<N> {
+        InFile::new(self.file_id, self.to_ptr(db).to_node(&db.parse_or_expand(self.file_id)))
+    }
+    pub fn to_ptr(&self, db: &dyn db::ExpandDatabase) -> AstPtr<N> {
+        db.ast_id_map(self.file_id).get(self.value)
+    }
+}
+
+pub type ErasedAstId = InFile<ErasedFileAstId>;
+
+impl ErasedAstId {
+    pub fn to_node(&self, db: &dyn db::ExpandDatabase) -> SyntaxNode {
+        self.to_ptr(db).to_node(&db.parse_or_expand(self.file_id))
+    }
+    pub fn to_ptr(&self, db: &dyn db::ExpandDatabase) -> SyntaxNodePtr {
+        db.ast_id_map(self.file_id).get_raw(self.value)
     }
 }
 
@@ -850,7 +887,7 @@ impl<L, R> InFile<Either<L, R>> {
     }
 }
 
-impl<'a> InFile<&'a SyntaxNode> {
+impl InFile<&SyntaxNode> {
     pub fn ancestors_with_macros(
         self,
         db: &dyn db::ExpandDatabase,
@@ -1011,6 +1048,18 @@ impl InFile<SyntaxToken> {
     }
 }
 
+#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
+pub struct InMacroFile<T> {
+    pub file_id: MacroFile,
+    pub value: T,
+}
+
+impl<T> From<InMacroFile<T>> for InFile<T> {
+    fn from(macro_file: InMacroFile<T>) -> Self {
+        InFile { file_id: macro_file.file_id.into(), value: macro_file.value }
+    }
+}
+
 fn ascend_node_border_tokens(
     db: &dyn db::ExpandDatabase,
     InFile { file_id, value: node }: InFile<&SyntaxNode>,

crates/hir-expand/src/mod_path.rs

@@ -126,7 +126,7 @@ struct Display<'a> {
     path: &'a ModPath,
 }
 
-impl<'a> fmt::Display for Display<'a> {
+impl fmt::Display for Display<'_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         display_fmt_path(self.db, self.path, f, true)
     }
@@ -137,7 +137,7 @@ struct UnescapedDisplay<'a> {
     path: &'a UnescapedModPath<'a>,
 }
 
-impl<'a> fmt::Display for UnescapedDisplay<'a> {
+impl fmt::Display for UnescapedDisplay<'_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         display_fmt_path(self.db, self.path.0, f, false)
     }

crates/hir-expand/src/name.rs

@@ -24,7 +24,7 @@ enum Repr {
     TupleField(usize),
 }
 
-impl<'a> UnescapedName<'a> {
+impl UnescapedName<'_> {
     /// Returns the textual representation of this name as a [`SmolStr`]. Prefer using this over
     /// [`ToString::to_string`] if possible as this conversion is cheaper in the general case.
     pub fn to_smol_str(&self) -> SmolStr {
@@ -40,7 +40,7 @@ impl<'a> UnescapedName<'a> {
         }
     }
 
-    pub fn display(&'a self, db: &dyn crate::db::ExpandDatabase) -> impl fmt::Display + 'a {
+    pub fn display(&self, db: &dyn crate::db::ExpandDatabase) -> impl fmt::Display + '_ {
         _ = db;
         UnescapedDisplay { name: self }
     }
@@ -96,6 +96,15 @@ impl Name {
         Name::new_inline("[missing name]")
     }
 
+    /// Returns true if this is a fake name for things missing in the source code. See
+    /// [`missing()`][Self::missing] for details.
+    ///
+    /// Use this method instead of comparing with `Self::missing()` as missing names
+    /// (ideally should) have a `gensym` semantics.
+    pub fn is_missing(&self) -> bool {
+        self == &Name::missing()
+    }
+
     /// Generates a new name which is only equal to itself, by incrementing a counter. Due
     /// its implementation, it should not be used in things that salsa considers, like
     /// type names or field names, and it should be only used in names of local variables
@@ -162,7 +171,7 @@ struct Display<'a> {
     name: &'a Name,
 }
 
-impl<'a> fmt::Display for Display<'a> {
+impl fmt::Display for Display<'_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match &self.name.0 {
             Repr::Text(text) => fmt::Display::fmt(&text, f),
@@ -175,7 +184,7 @@ struct UnescapedDisplay<'a> {
     name: &'a UnescapedName<'a>,
 }
 
-impl<'a> fmt::Display for UnescapedDisplay<'a> {
+impl fmt::Display for UnescapedDisplay<'_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match &self.name.0 .0 {
             Repr::Text(text) => {
@@ -282,8 +291,10 @@ pub mod known {
         alloc,
         iter,
         ops,
+        fmt,
         future,
         result,
+        string,
         boxed,
         option,
         prelude,
@@ -311,6 +322,7 @@ pub mod known {
         RangeToInclusive,
         RangeTo,
         Range,
+        String,
         Neg,
         Not,
         None,
@@ -321,6 +333,7 @@ pub mod known {
         iter_mut,
         len,
         is_empty,
+        as_str,
         new,
         // Builtin macros
         asm,
@@ -334,6 +347,7 @@ pub mod known {
         core_panic,
         env,
         file,
+        format,
         format_args_nl,
         format_args,
         global_asm,
@@ -365,6 +379,7 @@ pub mod known {
         cfg_eval,
         crate_type,
         derive,
+        derive_const,
         global_allocator,
         no_core,
         no_std,

crates/hir-ty/Cargo.toml

@@ -19,14 +19,15 @@ bitflags = "2.1.0"
 smallvec.workspace = true
 ena = "0.14.0"
 either = "1.7.0"
+oorandom = "11.1.3"
 tracing = "0.1.35"
 rustc-hash = "1.1.0"
 scoped-tls = "1.0.0"
-chalk-solve = { version = "0.91.0", default-features = false }
+chalk-solve = { version = "0.92.0", default-features = false }
-chalk-ir = "0.91.0"
+chalk-ir = "0.92.0"
-chalk-recursive = { version = "0.91.0", default-features = false }
+chalk-recursive = { version = "0.92.0", default-features = false }
-chalk-derive = "0.91.0"
+chalk-derive = "0.92.0"
-la-arena = { version = "0.3.0", path = "../../lib/la-arena" }
+la-arena.workspace = true
 once_cell = "1.17.0"
 triomphe.workspace = true
 nohash-hasher.workspace = true
@@ -47,7 +48,6 @@ limit.workspace = true
 expect-test = "1.4.0"
 tracing = "0.1.35"
 tracing-subscriber = { version = "0.3.16", default-features = false, features = [
-    "env-filter",
     "registry",
 ] }
 tracing-tree = "0.2.1"

crates/hir-ty/src/autoderef.rs

@@ -36,7 +36,7 @@ pub fn autoderef(
 ) -> impl Iterator<Item = Ty> {
     let mut table = InferenceTable::new(db, env);
     let ty = table.instantiate_canonical(ty);
-    let mut autoderef = Autoderef::new(&mut table, ty);
+    let mut autoderef = Autoderef::new(&mut table, ty, false);
     let mut v = Vec::new();
     while let Some((ty, _steps)) = autoderef.next() {
         // `ty` may contain unresolved inference variables. Since there's no chance they would be
@@ -63,12 +63,13 @@ pub(crate) struct Autoderef<'a, 'db> {
     ty: Ty,
     at_start: bool,
     steps: Vec<(AutoderefKind, Ty)>,
+    explicit: bool,
 }
 
 impl<'a, 'db> Autoderef<'a, 'db> {
-    pub(crate) fn new(table: &'a mut InferenceTable<'db>, ty: Ty) -> Self {
+    pub(crate) fn new(table: &'a mut InferenceTable<'db>, ty: Ty, explicit: bool) -> Self {
         let ty = table.resolve_ty_shallow(&ty);
-        Autoderef { table, ty, at_start: true, steps: Vec::new() }
+        Autoderef { table, ty, at_start: true, steps: Vec::new(), explicit }
     }
 
     pub(crate) fn step_count(&self) -> usize {
@@ -97,7 +98,7 @@ impl Iterator for Autoderef<'_, '_> {
             return None;
         }
 
-        let (kind, new_ty) = autoderef_step(self.table, self.ty.clone())?;
+        let (kind, new_ty) = autoderef_step(self.table, self.ty.clone(), self.explicit)?;
 
         self.steps.push((kind, self.ty.clone()));
         self.ty = new_ty;
@@ -109,8 +110,9 @@ impl Iterator for Autoderef<'_, '_> {
 pub(crate) fn autoderef_step(
     table: &mut InferenceTable<'_>,
     ty: Ty,
+    explicit: bool,
 ) -> Option<(AutoderefKind, Ty)> {
-    if let Some(derefed) = builtin_deref(table, &ty, false) {
+    if let Some(derefed) = builtin_deref(table, &ty, explicit) {
         Some((AutoderefKind::Builtin, table.resolve_ty_shallow(derefed)))
     } else {
         Some((AutoderefKind::Overloaded, deref_by_trait(table, ty)?))
@@ -124,7 +126,6 @@ pub(crate) fn builtin_deref<'ty>(
 ) -> Option<&'ty Ty> {
     match ty.kind(Interner) {
         TyKind::Ref(.., ty) => Some(ty),
-        // FIXME: Maybe accept this but diagnose if its not explicit?
         TyKind::Raw(.., ty) if explicit => Some(ty),
         &TyKind::Adt(chalk_ir::AdtId(adt), ref substs) => {
             if crate::lang_items::is_box(table.db, adt) {

crates/hir-ty/src/chalk_db.rs

@@ -5,13 +5,13 @@ use std::{iter, sync::Arc};
 
 use tracing::debug;
 
-use chalk_ir::{cast::Cast, fold::shift::Shift, CanonicalVarKinds};
+use chalk_ir::{cast::Caster, fold::shift::Shift, CanonicalVarKinds};
 use chalk_solve::rust_ir::{self, OpaqueTyDatumBound, WellKnownTrait};
 
 use base_db::CrateId;
 use hir_def::{
     hir::Movability,
-    lang_item::{lang_attr, LangItem, LangItemTarget},
+    lang_item::{LangItem, LangItemTarget},
     AssocItemId, BlockId, GenericDefId, HasModule, ItemContainerId, Lookup, TypeAliasId,
 };
 use hir_expand::name::name;
@@ -46,7 +46,7 @@ pub(crate) type AssociatedTyValue = chalk_solve::rust_ir::AssociatedTyValue<Inte
 pub(crate) type FnDefDatum = chalk_solve::rust_ir::FnDefDatum<Interner>;
 pub(crate) type Variances = chalk_ir::Variances<Interner>;
 
-impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
+impl chalk_solve::RustIrDatabase<Interner> for ChalkContext<'_> {
     fn associated_ty_data(&self, id: AssocTypeId) -> Arc<AssociatedTyDatum> {
         self.db.associated_ty_data(id)
     }
@@ -60,9 +60,37 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
         // FIXME: keep track of these
         Arc::new(rust_ir::AdtRepr { c: false, packed: false, int: None })
     }
-    fn discriminant_type(&self, _ty: chalk_ir::Ty<Interner>) -> chalk_ir::Ty<Interner> {
+    fn discriminant_type(&self, ty: chalk_ir::Ty<Interner>) -> chalk_ir::Ty<Interner> {
-        // FIXME: keep track of this
+        if let chalk_ir::TyKind::Adt(id, _) = ty.kind(Interner) {
-        chalk_ir::TyKind::Scalar(chalk_ir::Scalar::Uint(chalk_ir::UintTy::U32)).intern(Interner)
+            if let hir_def::AdtId::EnumId(e) = id.0 {
+                let enum_data = self.db.enum_data(e);
+                let ty = enum_data.repr.unwrap_or_default().discr_type();
+                return chalk_ir::TyKind::Scalar(match ty {
+                    hir_def::layout::IntegerType::Pointer(is_signed) => match is_signed {
+                        true => chalk_ir::Scalar::Int(chalk_ir::IntTy::Isize),
+                        false => chalk_ir::Scalar::Uint(chalk_ir::UintTy::Usize),
+                    },
+                    hir_def::layout::IntegerType::Fixed(size, is_signed) => match is_signed {
+                        true => chalk_ir::Scalar::Int(match size {
+                            hir_def::layout::Integer::I8 => chalk_ir::IntTy::I8,
+                            hir_def::layout::Integer::I16 => chalk_ir::IntTy::I16,
+                            hir_def::layout::Integer::I32 => chalk_ir::IntTy::I32,
+                            hir_def::layout::Integer::I64 => chalk_ir::IntTy::I64,
+                            hir_def::layout::Integer::I128 => chalk_ir::IntTy::I128,
+                        }),
+                        false => chalk_ir::Scalar::Uint(match size {
+                            hir_def::layout::Integer::I8 => chalk_ir::UintTy::U8,
+                            hir_def::layout::Integer::I16 => chalk_ir::UintTy::U16,
+                            hir_def::layout::Integer::I32 => chalk_ir::UintTy::U32,
+                            hir_def::layout::Integer::I64 => chalk_ir::UintTy::U64,
+                            hir_def::layout::Integer::I128 => chalk_ir::UintTy::U128,
+                        }),
+                    },
+                })
+                .intern(Interner);
+            }
+        }
+        chalk_ir::TyKind::Scalar(chalk_ir::Scalar::Uint(chalk_ir::UintTy::U8)).intern(Interner)
     }
     fn impl_datum(&self, impl_id: ImplId) -> Arc<ImplDatum> {
         self.db.impl_datum(self.krate, impl_id)
@@ -565,7 +593,7 @@ pub(crate) fn trait_datum_query(
     let where_clauses = convert_where_clauses(db, trait_.into(), &bound_vars);
     let associated_ty_ids = trait_data.associated_types().map(to_assoc_type_id).collect();
     let trait_datum_bound = rust_ir::TraitDatumBound { where_clauses };
-    let well_known = lang_attr(db.upcast(), trait_).and_then(well_known_trait_from_lang_item);
+    let well_known = db.lang_attr(trait_.into()).and_then(well_known_trait_from_lang_item);
     let trait_datum = TraitDatum {
         id: trait_id,
         binders: make_binders(db, &generic_params, trait_datum_bound),
@@ -593,6 +621,7 @@ fn well_known_trait_from_lang_item(item: LangItem) -> Option<WellKnownTrait> {
         LangItem::Unsize => WellKnownTrait::Unsize,
         LangItem::Tuple => WellKnownTrait::Tuple,
         LangItem::PointeeTrait => WellKnownTrait::Pointee,
+        LangItem::FnPtrTrait => WellKnownTrait::FnPtr,
         _ => return None,
     })
 }
@@ -614,6 +643,7 @@ fn lang_item_from_well_known_trait(trait_: WellKnownTrait) -> LangItem {
         WellKnownTrait::Unpin => LangItem::Unpin,
         WellKnownTrait::Unsize => LangItem::Unsize,
         WellKnownTrait::Pointee => LangItem::PointeeTrait,
+        WellKnownTrait::FnPtr => LangItem::FnPtrTrait,
     }
 }
 
@@ -844,28 +874,34 @@ pub(super) fn generic_predicate_to_inline_bound(
             }
             let args_no_self = trait_ref.substitution.as_slice(Interner)[1..]
                 .iter()
-                .map(|ty| ty.clone().cast(Interner))
+                .cloned()
+                .casted(Interner)
                 .collect();
             let trait_bound = rust_ir::TraitBound { trait_id: trait_ref.trait_id, args_no_self };
             Some(chalk_ir::Binders::new(binders, rust_ir::InlineBound::TraitBound(trait_bound)))
         }
         WhereClause::AliasEq(AliasEq { alias: AliasTy::Projection(projection_ty), ty }) => {
-            let trait_ = projection_ty.trait_(db);
+            let generics =
-            if projection_ty.self_type_parameter(db) != self_ty_shifted_in {
+                generics(db.upcast(), from_assoc_type_id(projection_ty.associated_ty_id).into());
+            let (assoc_args, trait_args) =
+                projection_ty.substitution.as_slice(Interner).split_at(generics.len_self());
+            let (self_ty, args_no_self) =
+                trait_args.split_first().expect("projection without trait self type");
+            if self_ty.assert_ty_ref(Interner) != &self_ty_shifted_in {
                 return None;
             }
-            let args_no_self = projection_ty.substitution.as_slice(Interner)[1..]
+
-                .iter()
+            let args_no_self = args_no_self.iter().cloned().casted(Interner).collect();
-                .map(|ty| ty.clone().cast(Interner))
+            let parameters = assoc_args.to_vec();
-                .collect();
+
             let alias_eq_bound = rust_ir::AliasEqBound {
                 value: ty.clone(),
                 trait_bound: rust_ir::TraitBound {
-                    trait_id: to_chalk_trait_id(trait_),
+                    trait_id: to_chalk_trait_id(projection_ty.trait_(db)),
                     args_no_self,
                 },
                 associated_ty_id: projection_ty.associated_ty_id,
-                parameters: Vec::new(), // FIXME we don't support generic associated types yet
+                parameters,
             };
             Some(chalk_ir::Binders::new(
                 binders,

crates/hir-ty/src/chalk_ext.rs

@@ -343,7 +343,8 @@ impl TyExt for Ty {
 
     fn is_copy(self, db: &dyn HirDatabase, owner: DefWithBodyId) -> bool {
         let crate_id = owner.module(db.upcast()).krate();
-        let Some(copy_trait) = db.lang_item(crate_id, LangItem::Copy).and_then(|x| x.as_trait()) else {
+        let Some(copy_trait) = db.lang_item(crate_id, LangItem::Copy).and_then(|it| it.as_trait())
+        else {
             return false;
         };
         let trait_ref = TyBuilder::trait_ref(db, copy_trait).push(self).build();

crates/hir-ty/src/consteval.rs

@@ -88,7 +88,7 @@ pub(crate) fn path_to_const(
                     ConstValue::Placeholder(to_placeholder_idx(db, p.into()))
                 }
                 ParamLoweringMode::Variable => match args.param_idx(p.into()) {
-                    Some(x) => ConstValue::BoundVar(BoundVar::new(debruijn, x)),
+                    Some(it) => ConstValue::BoundVar(BoundVar::new(debruijn, it)),
                     None => {
                         never!(
                             "Generic list doesn't contain this param: {:?}, {:?}, {:?}",
@@ -139,11 +139,11 @@ pub fn intern_const_ref(
     let bytes = match value {
         LiteralConstRef::Int(i) => {
             // FIXME: We should handle failure of layout better.
-            let size = layout.map(|x| x.size.bytes_usize()).unwrap_or(16);
+            let size = layout.map(|it| it.size.bytes_usize()).unwrap_or(16);
             ConstScalar::Bytes(i.to_le_bytes()[0..size].to_vec(), MemoryMap::default())
         }
         LiteralConstRef::UInt(i) => {
-            let size = layout.map(|x| x.size.bytes_usize()).unwrap_or(16);
+            let size = layout.map(|it| it.size.bytes_usize()).unwrap_or(16);
             ConstScalar::Bytes(i.to_le_bytes()[0..size].to_vec(), MemoryMap::default())
         }
         LiteralConstRef::Bool(b) => ConstScalar::Bytes(vec![*b as u8], MemoryMap::default()),
@@ -171,7 +171,7 @@ pub fn try_const_usize(db: &dyn HirDatabase, c: &Const) -> Option<u128> {
         chalk_ir::ConstValue::InferenceVar(_) => None,
         chalk_ir::ConstValue::Placeholder(_) => None,
         chalk_ir::ConstValue::Concrete(c) => match &c.interned {
-            ConstScalar::Bytes(x, _) => Some(u128::from_le_bytes(pad16(&x, false))),
+            ConstScalar::Bytes(it, _) => Some(u128::from_le_bytes(pad16(&it, false))),
             ConstScalar::UnevaluatedConst(c, subst) => {
                 let ec = db.const_eval(*c, subst.clone()).ok()?;
                 try_const_usize(db, &ec)
@@ -228,7 +228,7 @@ pub(crate) fn const_eval_query(
         }
         GeneralConstId::InTypeConstId(c) => db.mir_body(c.into())?,
     };
-    let c = interpret_mir(db, &body, false).0?;
+    let c = interpret_mir(db, body, false).0?;
     Ok(c)
 }
 
@@ -241,7 +241,7 @@ pub(crate) fn const_eval_static_query(
         Substitution::empty(Interner),
         db.trait_environment_for_body(def.into()),
     )?;
-    let c = interpret_mir(db, &body, false).0?;
+    let c = interpret_mir(db, body, false).0?;
     Ok(c)
 }
 
@@ -268,7 +268,7 @@ pub(crate) fn const_eval_discriminant_variant(
         Substitution::empty(Interner),
         db.trait_environment_for_body(def),
     )?;
-    let c = interpret_mir(db, &mir_body, false).0?;
+    let c = interpret_mir(db, mir_body, false).0?;
     let c = try_const_usize(db, &c).unwrap() as i128;
     Ok(c)
 }
@@ -293,7 +293,7 @@ pub(crate) fn eval_to_const(
     }
     let infer = ctx.clone().resolve_all();
     if let Ok(mir_body) = lower_to_mir(ctx.db, ctx.owner, &ctx.body, &infer, expr) {
-        if let Ok(result) = interpret_mir(db, &mir_body, true).0 {
+        if let Ok(result) = interpret_mir(db, Arc::new(mir_body), true).0 {
             return result;
         }
     }

crates/hir-ty/src/consteval/tests.rs

@@ -1,10 +1,11 @@
 use base_db::{fixture::WithFixture, FileId};
 use chalk_ir::Substitution;
 use hir_def::db::DefDatabase;
+use test_utils::skip_slow_tests;
 
 use crate::{
     consteval::try_const_usize, db::HirDatabase, mir::pad16, test_db::TestDB, Const, ConstScalar,
-    Interner,
+    Interner, MemoryMap,
 };
 
 use super::{
@@ -16,7 +17,7 @@ mod intrinsics;
 
 fn simplify(e: ConstEvalError) -> ConstEvalError {
     match e {
-        ConstEvalError::MirEvalError(MirEvalError::InFunction(_, e, _, _)) => {
+        ConstEvalError::MirEvalError(MirEvalError::InFunction(e, _)) => {
             simplify(ConstEvalError::MirEvalError(*e))
         }
         _ => e,
@@ -36,7 +37,37 @@ fn check_fail(ra_fixture: &str, error: impl FnOnce(ConstEvalError) -> bool) {
 
 #[track_caller]
 fn check_number(ra_fixture: &str, answer: i128) {
-    let (db, file_id) = TestDB::with_single_file(ra_fixture);
+    check_answer(ra_fixture, |b, _| {
+        assert_eq!(
+            b,
+            &answer.to_le_bytes()[0..b.len()],
+            "Bytes differ. In decimal form: actual = {}, expected = {answer}",
+            i128::from_le_bytes(pad16(b, true))
+        );
+    });
+}
+
+#[track_caller]
+fn check_str(ra_fixture: &str, answer: &str) {
+    check_answer(ra_fixture, |b, mm| {
+        let addr = usize::from_le_bytes(b[0..b.len() / 2].try_into().unwrap());
+        let size = usize::from_le_bytes(b[b.len() / 2..].try_into().unwrap());
+        let Some(bytes) = mm.get(addr, size) else {
+            panic!("string data missed in the memory map");
+        };
+        assert_eq!(
+            bytes,
+            answer.as_bytes(),
+            "Bytes differ. In string form: actual = {}, expected = {answer}",
+            String::from_utf8_lossy(bytes)
+        );
+    });
+}
+
+#[track_caller]
+fn check_answer(ra_fixture: &str, check: impl FnOnce(&[u8], &MemoryMap)) {
+    let (db, file_ids) = TestDB::with_many_files(ra_fixture);
+    let file_id = *file_ids.last().unwrap();
     let r = match eval_goal(&db, file_id) {
         Ok(t) => t,
         Err(e) => {
@@ -46,13 +77,8 @@ fn check_number(ra_fixture: &str, answer: i128) {
     };
     match &r.data(Interner).value {
         chalk_ir::ConstValue::Concrete(c) => match &c.interned {
-            ConstScalar::Bytes(b, _) => {
+            ConstScalar::Bytes(b, mm) => {
-                assert_eq!(
+                check(b, mm);
-                    b,
-                    &answer.to_le_bytes()[0..b.len()],
-                    "Bytes differ. In decimal form: actual = {}, expected = {answer}",
-                    i128::from_le_bytes(pad16(b, true))
-                );
             }
             x => panic!("Expected number but found {:?}", x),
         },
@@ -87,7 +113,7 @@ fn eval_goal(db: &TestDB, file_id: FileId) -> Result<Const, ConstEvalError> {
             }
             _ => None,
         })
-        .unwrap();
+        .expect("No const named GOAL found in the test");
     db.const_eval(const_id.into(), Substitution::empty(Interner))
 }
 
@@ -108,6 +134,7 @@ fn bit_op() {
     check_fail(r#"const GOAL: i8 = 1 << 8"#, |e| {
         e == ConstEvalError::MirEvalError(MirEvalError::Panic("Overflow in Shl".to_string()))
     });
+    check_number(r#"const GOAL: i32 = 100000000i32 << 11"#, (100000000i32 << 11) as i128);
 }
 
 #[test]
@@ -166,14 +193,21 @@ fn casts() {
     check_number(
         r#"
     //- minicore: coerce_unsized, index, slice
+    struct X {
+        unsize_field: [u8],
+    }
+
     const GOAL: usize = {
         let a = [10, 20, 3, 15];
         let x: &[i32] = &a;
-        let y: *const [i32] = x;
+        let x: *const [i32] = x;
-        let z = y as *const [u8]; // slice fat pointer cast don't touch metadata
+        let x = x as *const [u8]; // slice fat pointer cast don't touch metadata
-        let q = z as *const str;
+        let x = x as *const str;
-        let p = q as *const [u8];
+        let x = x as *const X;
-        let w = unsafe { &*z };
+        let x = x as *const [i16];
+        let x = x as *const X;
+        let x = x as *const [u8];
+        let w = unsafe { &*x };
         w.len()
     };
         "#,
@@ -198,6 +232,30 @@ fn raw_pointer_equality() {
     );
 }
 
+#[test]
+fn alignment() {
+    check_answer(
+        r#"
+//- minicore: transmute
+use core::mem::transmute;
+const GOAL: usize = {
+    let x: i64 = 2;
+    transmute(&x)
+}
+        "#,
+        |b, _| assert_eq!(b[0] % 8, 0),
+    );
+    check_answer(
+        r#"
+//- minicore: transmute
+use core::mem::transmute;
+static X: i64 = 12;
+const GOAL: usize = transmute(&X);
+        "#,
+        |b, _| assert_eq!(b[0] % 8, 0),
+    );
+}
+
 #[test]
 fn locals() {
     check_number(
@@ -1550,6 +1608,30 @@ fn closures() {
     );
 }
 
+#[test]
+fn manual_fn_trait_impl() {
+    check_number(
+        r#"
+//- minicore: fn, copy
+struct S(i32);
+
+impl FnOnce<(i32, i32)> for S {
+    type Output = i32;
+
+    extern "rust-call" fn call_once(self, arg: (i32, i32)) -> i32 {
+        arg.0 + arg.1 + self.0
+    }
+}
+
+const GOAL: i32 = {
+    let s = S(1);
+    s(2, 3)
+};
+"#,
+        6,
+    );
+}
+
 #[test]
 fn closure_and_impl_fn() {
     check_number(
@@ -1661,6 +1743,18 @@ fn function_pointer() {
         "#,
         5,
     );
+    check_number(
+        r#"
+    fn add2(x: u8) -> u8 {
+        x + 2
+    }
+    const GOAL: u8 = {
+        let plus2 = add2 as fn(u8) -> u8;
+        plus2(3)
+    };
+        "#,
+        5,
+    );
     check_number(
         r#"
     //- minicore: coerce_unsized, index, slice
@@ -1849,6 +1943,38 @@ fn dyn_trait() {
     );
 }
 
+#[test]
+fn coerce_unsized() {
+    check_number(
+        r#"
+//- minicore: coerce_unsized, deref_mut, slice, index, transmute, non_null
+use core::ops::{Deref, DerefMut, CoerceUnsized};
+use core::{marker::Unsize, mem::transmute, ptr::NonNull};
+
+struct ArcInner<T: ?Sized> {
+    strong: usize,
+    weak: usize,
+    data: T,
+}
+
+pub struct Arc<T: ?Sized> {
+    inner: NonNull<ArcInner<T>>,
+}
+
+impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Arc<U>> for Arc<T> {}
+
+const GOAL: usize = {
+    let x = transmute::<usize, Arc<[i32; 3]>>(12);
+    let y: Arc<[i32]> = x;
+    let z = transmute::<Arc<[i32]>, (usize, usize)>(y);
+    z.1
+};
+
+        "#,
+        3,
+    );
+}
+
 #[test]
 fn boxes() {
     check_number(
@@ -1960,6 +2086,17 @@ fn array_and_index() {
     );
 }
 
+#[test]
+fn string() {
+    check_str(
+        r#"
+    //- minicore: coerce_unsized, index, slice
+    const GOAL: &str = "hello";
+        "#,
+        "hello",
+    );
+}
+
 #[test]
 fn byte_string() {
     check_number(
@@ -2018,6 +2155,57 @@ fn consts() {
     "#,
         6,
     );
+
+    check_number(
+        r#"
+    const F1: i32 = 2147483647;
+    const F2: i32 = F1 - 25;
+    const GOAL: i32 = F2;
+    "#,
+        2147483622,
+    );
+
+    check_number(
+        r#"
+    const F1: i32 = -2147483648;
+    const F2: i32 = F1 + 18;
+    const GOAL: i32 = F2;
+    "#,
+        -2147483630,
+    );
+
+    check_number(
+        r#"
+    const F1: i32 = 10;
+    const F2: i32 = F1 - 20;
+    const GOAL: i32 = F2;
+    "#,
+        -10,
+    );
+
+    check_number(
+        r#"
+    const F1: i32 = 25;
+    const F2: i32 = F1 - 25;
+    const GOAL: i32 = F2;
+    "#,
+        0,
+    );
+
+    check_number(
+        r#"
+    const A: i32 = -2147483648;
+    const GOAL: bool = A > 0;
+    "#,
+        0,
+    );
+
+    check_number(
+        r#"
+    const GOAL: i64 = (-2147483648_i32) as i64;
+    "#,
+        -2147483648,
+    );
 }
 
 #[test]
@@ -2285,6 +2473,25 @@ fn const_trait_assoc() {
     "#,
         32,
     );
+    check_number(
+        r#"
+    //- /a/lib.rs crate:a
+    pub trait ToConst {
+        const VAL: usize;
+    }
+    pub const fn to_const<T: ToConst>() -> usize {
+        T::VAL
+    }
+    //- /main.rs crate:main deps:a
+    use a::{ToConst, to_const};
+    struct U0;
+    impl ToConst for U0 {
+        const VAL: usize = 5;
+    }
+    const GOAL: usize = to_const::<U0>();
+    "#,
+        5,
+    );
     check_number(
         r#"
     struct S<T>(*mut T);
@@ -2310,22 +2517,12 @@ fn const_trait_assoc() {
     );
 }
 
-#[test]
-fn panic_messages() {
-    check_fail(
-        r#"
-    //- minicore: panic
-    const GOAL: u8 = {
-        let x: u16 = 2;
-        panic!("hello");
-    };
-    "#,
-        |e| e == ConstEvalError::MirEvalError(MirEvalError::Panic("hello".to_string())),
-    );
-}
-
 #[test]
 fn exec_limits() {
+    if skip_slow_tests() {
+        return;
+    }
+
     check_fail(
         r#"
     const GOAL: usize = loop {};
@@ -2339,7 +2536,7 @@ fn exec_limits() {
     }
     const GOAL: i32 = f(0);
     "#,
-        |e| e == ConstEvalError::MirEvalError(MirEvalError::StackOverflow),
+        |e| e == ConstEvalError::MirEvalError(MirEvalError::ExecutionLimitExceeded),
     );
     // Reasonable code should still work
     check_number(
@@ -2362,6 +2559,28 @@ fn exec_limits() {
     );
 }
 
+#[test]
+fn memory_limit() {
+    check_fail(
+        r#"
+        extern "Rust" {
+            #[rustc_allocator]
+            fn __rust_alloc(size: usize, align: usize) -> *mut u8;
+        }
+
+        const GOAL: u8 = unsafe {
+            __rust_alloc(30_000_000_000, 1); // 30GB
+            2
+        };
+        "#,
+        |e| {
+            e == ConstEvalError::MirEvalError(MirEvalError::Panic(
+                "Memory allocation of 30000000000 bytes failed".to_string(),
+            ))
+        },
+    );
+}
+
 #[test]
 fn type_error() {
     check_fail(
@@ -2376,6 +2595,37 @@ fn type_error() {
     );
 }
 
+#[test]
+fn unsized_field() {
+    check_number(
+        r#"
+    //- minicore: coerce_unsized, index, slice, transmute
+    use core::mem::transmute;
+
+    struct Slice([u8]);
+    struct Slice2(Slice);
+
+    impl Slice2 {
+        fn as_inner(&self) -> &Slice {
+            &self.0
+        }
+
+        fn as_bytes(&self) -> &[u8] {
+            &self.as_inner().0
+        }
+    }
+
+    const GOAL: u8 = unsafe {
+        let x: &[u8] = &[1, 2, 3];
+        let x: &Slice2 = transmute(x);
+        let x = x.as_bytes();
+        x[0] + x[1] + x[2]
+    };
+        "#,
+        6,
+    );
+}
+
 #[test]
 fn unsized_local() {
     check_fail(

crates/hir-ty/src/consteval/tests/intrinsics.rs

@@ -14,6 +14,171 @@ fn size_of() {
     );
 }
 
+#[test]
+fn size_of_val() {
+    check_number(
+        r#"
+        //- minicore: coerce_unsized
+        extern "rust-intrinsic" {
+            pub fn size_of_val<T: ?Sized>(_: *const T) -> usize;
+        }
+
+        struct X(i32, u8);
+
+        const GOAL: usize = size_of_val(&X(1, 2));
+        "#,
+        8,
+    );
+    check_number(
+        r#"
+        //- minicore: coerce_unsized
+        extern "rust-intrinsic" {
+            pub fn size_of_val<T: ?Sized>(_: *const T) -> usize;
+        }
+
+        const GOAL: usize = {
+            let it: &[i32] = &[1, 2, 3];
+            size_of_val(it)
+        };
+        "#,
+        12,
+    );
+    check_number(
+        r#"
+        //- minicore: coerce_unsized, transmute
+        use core::mem::transmute;
+
+        extern "rust-intrinsic" {
+            pub fn size_of_val<T: ?Sized>(_: *const T) -> usize;
+        }
+
+        struct X {
+            x: i64,
+            y: u8,
+            t: [i32],
+        }
+
+        const GOAL: usize = unsafe {
+            let y: &X = transmute([0usize, 3]);
+            size_of_val(y)
+        };
+        "#,
+        24,
+    );
+    check_number(
+        r#"
+        //- minicore: coerce_unsized, transmute
+        use core::mem::transmute;
+
+        extern "rust-intrinsic" {
+            pub fn size_of_val<T: ?Sized>(_: *const T) -> usize;
+        }
+
+        struct X {
+            x: i32,
+            y: i64,
+            t: [u8],
+        }
+
+        const GOAL: usize = unsafe {
+            let y: &X = transmute([0usize, 15]);
+            size_of_val(y)
+        };
+    "#,
+        32,
+    );
+    check_number(
+        r#"
+        //- minicore: coerce_unsized, fmt, builtin_impls
+        extern "rust-intrinsic" {
+            pub fn size_of_val<T: ?Sized>(_: *const T) -> usize;
+        }
+
+        const GOAL: usize = {
+            let x: &i16 = &5;
+            let y: &dyn core::fmt::Debug = x;
+            let z: &dyn core::fmt::Debug = &y;
+            size_of_val(x) + size_of_val(y) * 10 + size_of_val(z) * 100
+        };
+        "#,
+        1622,
+    );
+    check_number(
+        r#"
+        //- minicore: coerce_unsized
+        extern "rust-intrinsic" {
+            pub fn size_of_val<T: ?Sized>(_: *const T) -> usize;
+        }
+
+        const GOAL: usize = {
+            size_of_val("salam")
+        };
+        "#,
+        5,
+    );
+}
+
+#[test]
+fn min_align_of_val() {
+    check_number(
+        r#"
+        //- minicore: coerce_unsized
+        extern "rust-intrinsic" {
+            pub fn min_align_of_val<T: ?Sized>(_: *const T) -> usize;
+        }
+
+        struct X(i32, u8);
+
+        const GOAL: usize = min_align_of_val(&X(1, 2));
+        "#,
+        4,
+    );
+    check_number(
+        r#"
+        //- minicore: coerce_unsized
+        extern "rust-intrinsic" {
+            pub fn min_align_of_val<T: ?Sized>(_: *const T) -> usize;
+        }
+
+        const GOAL: usize = {
+            let x: &[i32] = &[1, 2, 3];
+            min_align_of_val(x)
+        };
+        "#,
+        4,
+    );
+}
+
+#[test]
+fn type_name() {
+    check_str(
+        r#"
+        extern "rust-intrinsic" {
+            pub fn type_name<T: ?Sized>() -> &'static str;
+        }
+
+        const GOAL: &str = type_name::<i32>();
+        "#,
+        "i32",
+    );
+    check_str(
+        r#"
+        extern "rust-intrinsic" {
+            pub fn type_name<T: ?Sized>() -> &'static str;
+        }
+
+        mod mod1 {
+            pub mod mod2 {
+                pub struct Ty;
+            }
+        }
+
+        const GOAL: &str = type_name::<mod1::mod2::Ty>();
+        "#,
+        "mod1::mod2::Ty",
+    );
+}
+
 #[test]
 fn transmute() {
     check_number(
@@ -28,10 +193,29 @@ fn transmute() {
     );
 }
 
+#[test]
+fn read_via_copy() {
+    check_number(
+        r#"
+        extern "rust-intrinsic" {
+            pub fn read_via_copy<T>(e: *const T) -> T;
+            pub fn volatile_load<T>(e: *const T) -> T;
+        }
+
+        const GOAL: i32 = {
+            let x = 2;
+            read_via_copy(&x) + volatile_load(&x)
+        };
+        "#,
+        4,
+    );
+}
+
 #[test]
 fn const_eval_select() {
     check_number(
         r#"
+        //- minicore: fn
         extern "rust-intrinsic" {
             pub fn const_eval_select<ARG, F, G, RET>(arg: ARG, called_in_const: F, called_at_rt: G) -> RET
             where
@@ -68,7 +252,7 @@ fn wrapping_add() {
 }
 
 #[test]
-fn saturating_add() {
+fn saturating() {
     check_number(
         r#"
         extern "rust-intrinsic" {
@@ -79,6 +263,16 @@ fn saturating_add() {
         "#,
         255,
     );
+    check_number(
+        r#"
+        extern "rust-intrinsic" {
+            pub fn saturating_sub<T>(a: T, b: T) -> T;
+        }
+
+        const GOAL: bool = saturating_sub(5u8, 7) == 0 && saturating_sub(8u8, 4) == 4;
+        "#,
+        1,
+    );
     check_number(
         r#"
         extern "rust-intrinsic" {
@@ -112,6 +306,7 @@ fn allocator() {
             *ptr = 23;
             *ptr2 = 32;
             let ptr = __rust_realloc(ptr, 4, 1, 8);
+            let ptr = __rust_realloc(ptr, 8, 1, 3);
             let ptr2 = ((ptr as usize) + 1) as *mut u8;
             *ptr + *ptr2
         };
@@ -159,6 +354,24 @@ fn needs_drop() {
     );
 }
 
+#[test]
+fn discriminant_value() {
+    check_number(
+        r#"
+        //- minicore: discriminant, option
+        use core::marker::DiscriminantKind;
+        extern "rust-intrinsic" {
+            pub fn discriminant_value<T>(v: &T) -> <T as DiscriminantKind>::Discriminant;
+        }
+        const GOAL: bool = {
+            discriminant_value(&Some(2i32)) == discriminant_value(&Some(5i32))
+                && discriminant_value(&Some(2i32)) != discriminant_value(&None::<i32>)
+        };
+        "#,
+        1,
+    );
+}
+
 #[test]
 fn likely() {
     check_number(
@@ -327,6 +540,24 @@ fn copy_nonoverlapping() {
     );
 }
 
+#[test]
+fn write_bytes() {
+    check_number(
+        r#"
+        extern "rust-intrinsic" {
+            fn write_bytes<T>(dst: *mut T, val: u8, count: usize);
+        }
+
+        const GOAL: i32 = unsafe {
+            let mut x = 2;
+            write_bytes(&mut x, 5, 1);
+            x
+        };
+        "#,
+        0x05050505,
+    );
+}
+
 #[test]
 fn copy() {
     check_number(
@@ -362,6 +593,20 @@ fn ctpop() {
     );
 }
 
+#[test]
+fn ctlz() {
+    check_number(
+        r#"
+        extern "rust-intrinsic" {
+            pub fn ctlz<T: Copy>(x: T) -> T;
+        }
+
+        const GOAL: u8 = ctlz(0b0001_1100_u8);
+        "#,
+        3,
+    );
+}
+
 #[test]
 fn cttz() {
     check_number(
@@ -375,3 +620,85 @@ fn cttz() {
         3,
     );
 }
+
+#[test]
+fn rotate() {
+    check_number(
+        r#"
+        extern "rust-intrinsic" {
+            pub fn rotate_left<T: Copy>(x: T, y: T) -> T;
+        }
+
+        const GOAL: i64 = rotate_left(0xaa00000000006e1i64, 12);
+        "#,
+        0x6e10aa,
+    );
+    check_number(
+        r#"
+        extern "rust-intrinsic" {
+            pub fn rotate_right<T: Copy>(x: T, y: T) -> T;
+        }
+
+        const GOAL: i64 = rotate_right(0x6e10aa, 12);
+        "#,
+        0xaa00000000006e1,
+    );
+    check_number(
+        r#"
+        extern "rust-intrinsic" {
+            pub fn rotate_left<T: Copy>(x: T, y: T) -> T;
+        }
+
+        const GOAL: i8 = rotate_left(129, 2);
+        "#,
+        6,
+    );
+    check_number(
+        r#"
+        extern "rust-intrinsic" {
+            pub fn rotate_right<T: Copy>(x: T, y: T) -> T;
+        }
+
+        const GOAL: i32 = rotate_right(10006016, 1020315);
+        "#,
+        320192512,
+    );
+}
+
+#[test]
+fn simd() {
+    check_number(
+        r#"
+        pub struct i8x16(
+            i8,i8,i8,i8,i8,i8,i8,i8,i8,i8,i8,i8,i8,i8,i8,i8,
+        );
+        extern "platform-intrinsic" {
+            pub fn simd_bitmask<T, U>(x: T) -> U;
+        }
+        const GOAL: u16 = simd_bitmask(i8x16(
+            0, 1, 0, 0, 2, 255, 100, 0, 50, 0, 1, 1, 0, 0, 0, 0
+        ));
+        "#,
+        0b0000110101110010,
+    );
+    check_number(
+        r#"
+        pub struct i8x16(
+            i8,i8,i8,i8,i8,i8,i8,i8,i8,i8,i8,i8,i8,i8,i8,i8,
+        );
+        extern "platform-intrinsic" {
+            pub fn simd_lt<T, U>(x: T, y: T) -> U;
+            pub fn simd_bitmask<T, U>(x: T) -> U;
+        }
+        const GOAL: u16 = simd_bitmask(simd_lt::<i8x16, i8x16>(
+            i8x16(
+                -105, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
+            ),
+            i8x16(
+                -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
+            ),
+        ));
+        "#,
+        0xFFFF,
+    );
+}

crates/hir-ty/src/db.rs

@@ -110,6 +110,14 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     #[salsa::invoke(crate::layout::target_data_layout_query)]
     fn target_data_layout(&self, krate: CrateId) -> Option<Arc<TargetDataLayout>>;
 
+    #[salsa::invoke(crate::method_resolution::lookup_impl_method_query)]
+    fn lookup_impl_method(
+        &self,
+        env: Arc<crate::TraitEnvironment>,
+        func: FunctionId,
+        fn_subst: Substitution,
+    ) -> (FunctionId, Substitution);
+
     #[salsa::invoke(crate::lower::callable_item_sig)]
     fn callable_item_signature(&self, def: CallableDefId) -> PolyFnSig;
 

crates/hir-ty/src/diagnostics.rs

@@ -5,7 +5,7 @@ mod unsafe_check;
 mod decl_check;
 
 pub use crate::diagnostics::{
-    decl_check::{incorrect_case, IncorrectCase},
+    decl_check::{incorrect_case, CaseType, IncorrectCase},
     expr::{
         record_literal_missing_fields, record_pattern_missing_fields, BodyValidationDiagnostic,
     },

crates/hir-ty/src/diagnostics/decl_check.rs

@@ -57,11 +57,11 @@ pub fn incorrect_case(
 
 #[derive(Debug)]
 pub enum CaseType {
-    // `some_var`
+    /// `some_var`
     LowerSnakeCase,
-    // `SOME_CONST`
+    /// `SOME_CONST`
     UpperSnakeCase,
-    // `SomeStruct`
+    /// `SomeStruct`
     UpperCamelCase,
 }
 
@@ -181,6 +181,7 @@ impl<'a> DeclValidator<'a> {
                 AttrDefId::TraitAliasId(taid) => Some(taid.lookup(self.db.upcast()).container.into()),
                 AttrDefId::ImplId(iid) => Some(iid.lookup(self.db.upcast()).container.into()),
                 AttrDefId::ExternBlockId(id) => Some(id.lookup(self.db.upcast()).container.into()),
+                AttrDefId::ExternCrateId(id) =>  Some(id.lookup(self.db.upcast()).container.into()),
                 // These warnings should not explore macro definitions at all
                 AttrDefId::MacroId(_) => None,
                 AttrDefId::AdtId(aid) => match aid {

crates/hir-ty/src/display.rs

@@ -192,7 +192,7 @@ pub trait HirDisplay {
     }
 }
 
-impl<'a> HirFormatter<'a> {
+impl HirFormatter<'_> {
     pub fn write_joined<T: HirDisplay>(
         &mut self,
         iter: impl IntoIterator<Item = T>,
@@ -342,7 +342,7 @@ impl<T: HirDisplay> HirDisplayWrapper<'_, T> {
     }
 }
 
-impl<'a, T> fmt::Display for HirDisplayWrapper<'a, T>
+impl<T> fmt::Display for HirDisplayWrapper<'_, T>
 where
     T: HirDisplay,
 {
@@ -360,7 +360,7 @@ where
 
 const TYPE_HINT_TRUNCATION: &str = "…";
 
-impl<T: HirDisplay> HirDisplay for &'_ T {
+impl<T: HirDisplay> HirDisplay for &T {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
         HirDisplay::hir_fmt(*self, f)
     }
@@ -446,28 +446,6 @@ impl HirDisplay for Const {
     }
 }
 
-pub struct HexifiedConst(pub Const);
-
-impl HirDisplay for HexifiedConst {
-    fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
-        let data = &self.0.data(Interner);
-        if let TyKind::Scalar(s) = data.ty.kind(Interner) {
-            if matches!(s, Scalar::Int(_) | Scalar::Uint(_)) {
-                if let ConstValue::Concrete(c) = &data.value {
-                    if let ConstScalar::Bytes(b, m) = &c.interned {
-                        let value = u128::from_le_bytes(pad16(b, false));
-                        if value >= 10 {
-                            render_const_scalar(f, &b, m, &data.ty)?;
-                            return write!(f, " ({:#X})", value);
-                        }
-                    }
-                }
-            }
-        }
-        self.0.hir_fmt(f)
-    }
-}
-
 fn render_const_scalar(
     f: &mut HirFormatter<'_>,
     b: &[u8],
@@ -481,28 +459,28 @@ fn render_const_scalar(
         TyKind::Scalar(s) => match s {
             Scalar::Bool => write!(f, "{}", if b[0] == 0 { false } else { true }),
             Scalar::Char => {
-                let x = u128::from_le_bytes(pad16(b, false)) as u32;
+                let it = u128::from_le_bytes(pad16(b, false)) as u32;
-                let Ok(c) = char::try_from(x) else {
+                let Ok(c) = char::try_from(it) else {
                     return f.write_str("<unicode-error>");
                 };
                 write!(f, "{c:?}")
             }
             Scalar::Int(_) => {
-                let x = i128::from_le_bytes(pad16(b, true));
+                let it = i128::from_le_bytes(pad16(b, true));
-                write!(f, "{x}")
+                write!(f, "{it}")
             }
             Scalar::Uint(_) => {
-                let x = u128::from_le_bytes(pad16(b, false));
+                let it = u128::from_le_bytes(pad16(b, false));
-                write!(f, "{x}")
+                write!(f, "{it}")
             }
             Scalar::Float(fl) => match fl {
                 chalk_ir::FloatTy::F32 => {
-                    let x = f32::from_le_bytes(b.try_into().unwrap());
+                    let it = f32::from_le_bytes(b.try_into().unwrap());
-                    write!(f, "{x:?}")
+                    write!(f, "{it:?}")
                 }
                 chalk_ir::FloatTy::F64 => {
-                    let x = f64::from_le_bytes(b.try_into().unwrap());
+                    let it = f64::from_le_bytes(b.try_into().unwrap());
-                    write!(f, "{x:?}")
+                    write!(f, "{it:?}")
                 }
             },
         },
@@ -636,7 +614,8 @@ fn render_const_scalar(
                 }
                 hir_def::AdtId::EnumId(e) => {
                     let Some((var_id, var_layout)) =
-                            detect_variant_from_bytes(&layout, f.db, krate, b, e) else {
+                        detect_variant_from_bytes(&layout, f.db, krate, b, e)
+                    else {
                         return f.write_str("<failed-to-detect-variant>");
                     };
                     let data = &f.db.enum_data(e).variants[var_id];
@@ -658,8 +637,8 @@ fn render_const_scalar(
         }
         TyKind::FnDef(..) => ty.hir_fmt(f),
         TyKind::Function(_) | TyKind::Raw(_, _) => {
-            let x = u128::from_le_bytes(pad16(b, false));
+            let it = u128::from_le_bytes(pad16(b, false));
-            write!(f, "{:#X} as ", x)?;
+            write!(f, "{:#X} as ", it)?;
             ty.hir_fmt(f)
         }
         TyKind::Array(ty, len) => {
@@ -735,7 +714,7 @@ fn render_variant_after_name(
                 }
                 write!(f, " }}")?;
             } else {
-                let mut it = it.map(|x| x.0);
+                let mut it = it.map(|it| it.0);
                 write!(f, "(")?;
                 if let Some(id) = it.next() {
                     render_field(f, id)?;
@@ -1277,19 +1256,20 @@ fn hir_fmt_generics(
                         i: usize,
                         parameters: &Substitution,
                     ) -> bool {
-                        if parameter.ty(Interner).map(|x| x.kind(Interner)) == Some(&TyKind::Error)
+                        if parameter.ty(Interner).map(|it| it.kind(Interner))
+                            == Some(&TyKind::Error)
                         {
                             return true;
                         }
                         if let Some(ConstValue::Concrete(c)) =
-                            parameter.constant(Interner).map(|x| &x.data(Interner).value)
+                            parameter.constant(Interner).map(|it| &it.data(Interner).value)
                         {
                             if c.interned == ConstScalar::Unknown {
                                 return true;
                             }
                         }
                         let default_parameter = match default_parameters.get(i) {
-                            Some(x) => x,
+                            Some(it) => it,
                             None => return true,
                         };
                         let actual_default =

crates/hir-ty/src/infer.rs

@@ -290,7 +290,7 @@ impl Default for InternedStandardTypes {
 ///    ```
 ///
 ///    Note that for a struct, the 'deep' unsizing of the struct is not recorded.
-///    E.g., `struct Foo<T> { x: T }` we can coerce &Foo<[i32; 4]> to &Foo<[i32]>
+///    E.g., `struct Foo<T> { it: T }` we can coerce &Foo<[i32; 4]> to &Foo<[i32]>
 ///    The autoderef and -ref are the same as in the above example, but the type
 ///    stored in `unsize` is `Foo<[i32]>`, we don't store any further detail about
 ///    the underlying conversions from `[i32; 4]` to `[i32]`.
@@ -1172,7 +1172,7 @@ impl<'a> InferenceContext<'a> {
         unresolved: Option<usize>,
         path: &ModPath,
     ) -> (Ty, Option<VariantId>) {
-        let remaining = unresolved.map(|x| path.segments()[x..].len()).filter(|x| x > &0);
+        let remaining = unresolved.map(|it| path.segments()[it..].len()).filter(|it| it > &0);
         match remaining {
             None => {
                 let variant = ty.as_adt().and_then(|(adt_id, _)| match adt_id {
@@ -1232,7 +1232,9 @@ impl<'a> InferenceContext<'a> {
             .as_function()?
             .lookup(self.db.upcast())
             .container
-        else { return None };
+        else {
+            return None;
+        };
         self.resolve_output_on(trait_)
     }
 
@@ -1322,7 +1324,7 @@ impl Expectation {
     /// The primary use case is where the expected type is a fat pointer,
     /// like `&[isize]`. For example, consider the following statement:
     ///
-    ///     let x: &[isize] = &[1, 2, 3];
+    ///     let it: &[isize] = &[1, 2, 3];
     ///
     /// In this case, the expected type for the `&[1, 2, 3]` expression is
     /// `&[isize]`. If however we were to say that `[1, 2, 3]` has the

crates/hir-ty/src/infer/closure.rs

@@ -139,7 +139,7 @@ impl HirPlace {
     ) -> CaptureKind {
         match current_capture {
             CaptureKind::ByRef(BorrowKind::Mut { .. }) => {
-                if self.projections[len..].iter().any(|x| *x == ProjectionElem::Deref) {
+                if self.projections[len..].iter().any(|it| *it == ProjectionElem::Deref) {
                     current_capture = CaptureKind::ByRef(BorrowKind::Unique);
                 }
             }
@@ -199,7 +199,7 @@ impl CapturedItem {
                             .to_string(),
                         VariantData::Tuple(fields) => fields
                             .iter()
-                            .position(|x| x.0 == f.local_id)
+                            .position(|it| it.0 == f.local_id)
                             .unwrap_or_default()
                             .to_string(),
                         VariantData::Unit => "[missing field]".to_string(),
@@ -439,10 +439,10 @@ impl InferenceContext<'_> {
     }
 
     fn walk_expr(&mut self, tgt_expr: ExprId) {
-        if let Some(x) = self.result.expr_adjustments.get_mut(&tgt_expr) {
+        if let Some(it) = self.result.expr_adjustments.get_mut(&tgt_expr) {
             // FIXME: this take is completely unneeded, and just is here to make borrow checker
             // happy. Remove it if you can.
-            let x_taken = mem::take(x);
+            let x_taken = mem::take(it);
             self.walk_expr_with_adjust(tgt_expr, &x_taken);
             *self.result.expr_adjustments.get_mut(&tgt_expr).unwrap() = x_taken;
         } else {
@@ -536,7 +536,7 @@ impl InferenceContext<'_> {
                 if let &Some(expr) = spread {
                     self.consume_expr(expr);
                 }
-                self.consume_exprs(fields.iter().map(|x| x.expr));
+                self.consume_exprs(fields.iter().map(|it| it.expr));
             }
             Expr::Field { expr, name: _ } => self.select_from_expr(*expr),
             Expr::UnaryOp { expr, op: UnaryOp::Deref } => {
@@ -548,7 +548,7 @@ impl InferenceContext<'_> {
                 } else if let Some((f, _)) = self.result.method_resolution(tgt_expr) {
                     let mutability = 'b: {
                         if let Some(deref_trait) =
-                            self.resolve_lang_item(LangItem::DerefMut).and_then(|x| x.as_trait())
+                            self.resolve_lang_item(LangItem::DerefMut).and_then(|it| it.as_trait())
                         {
                             if let Some(deref_fn) =
                                 self.db.trait_data(deref_trait).method_by_name(&name![deref_mut])
@@ -615,8 +615,8 @@ impl InferenceContext<'_> {
                         "We sort closures, so we should always have data for inner closures",
                     );
                 let mut cc = mem::take(&mut self.current_captures);
-                cc.extend(captures.iter().filter(|x| self.is_upvar(&x.place)).map(|x| {
+                cc.extend(captures.iter().filter(|it| self.is_upvar(&it.place)).map(|it| {
-                    CapturedItemWithoutTy { place: x.place.clone(), kind: x.kind, span: x.span }
+                    CapturedItemWithoutTy { place: it.place.clone(), kind: it.kind, span: it.span }
                 }));
                 self.current_captures = cc;
             }
@@ -694,7 +694,7 @@ impl InferenceContext<'_> {
                 },
             },
         }
-        if self.result.pat_adjustments.get(&p).map_or(false, |x| !x.is_empty()) {
+        if self.result.pat_adjustments.get(&p).map_or(false, |it| !it.is_empty()) {
             for_mut = BorrowKind::Unique;
         }
         self.body.walk_pats_shallow(p, |p| self.walk_pat_inner(p, update_result, for_mut));
@@ -706,9 +706,9 @@ impl InferenceContext<'_> {
 
     fn expr_ty_after_adjustments(&self, e: ExprId) -> Ty {
         let mut ty = None;
-        if let Some(x) = self.result.expr_adjustments.get(&e) {
+        if let Some(it) = self.result.expr_adjustments.get(&e) {
-            if let Some(x) = x.last() {
+            if let Some(it) = it.last() {
-                ty = Some(x.target.clone());
+                ty = Some(it.target.clone());
             }
         }
         ty.unwrap_or_else(|| self.expr_ty(e))
@@ -727,7 +727,7 @@ impl InferenceContext<'_> {
             // FIXME: We handle closure as a special case, since chalk consider every closure as copy. We
             // should probably let chalk know which closures are copy, but I don't know how doing it
             // without creating query cycles.
-            return self.result.closure_info.get(id).map(|x| x.1 == FnTrait::Fn).unwrap_or(true);
+            return self.result.closure_info.get(id).map(|it| it.1 == FnTrait::Fn).unwrap_or(true);
         }
         self.table.resolve_completely(ty).is_copy(self.db, self.owner)
     }
@@ -748,7 +748,7 @@ impl InferenceContext<'_> {
     }
 
     fn minimize_captures(&mut self) {
-        self.current_captures.sort_by_key(|x| x.place.projections.len());
+        self.current_captures.sort_by_key(|it| it.place.projections.len());
         let mut hash_map = HashMap::<HirPlace, usize>::new();
         let result = mem::take(&mut self.current_captures);
         for item in result {
@@ -759,7 +759,7 @@ impl InferenceContext<'_> {
                     break Some(*k);
                 }
                 match it.next() {
-                    Some(x) => lookup_place.projections.push(x.clone()),
+                    Some(it) => lookup_place.projections.push(it.clone()),
                     None => break None,
                 }
             };
@@ -780,7 +780,7 @@ impl InferenceContext<'_> {
     }
 
     fn consume_with_pat(&mut self, mut place: HirPlace, pat: PatId) {
-        let cnt = self.result.pat_adjustments.get(&pat).map(|x| x.len()).unwrap_or_default();
+        let cnt = self.result.pat_adjustments.get(&pat).map(|it| it.len()).unwrap_or_default();
         place.projections = place
             .projections
             .iter()
@@ -894,10 +894,10 @@ impl InferenceContext<'_> {
 
     fn closure_kind(&self) -> FnTrait {
         let mut r = FnTrait::Fn;
-        for x in &self.current_captures {
+        for it in &self.current_captures {
             r = cmp::min(
                 r,
-                match &x.kind {
+                match &it.kind {
                     CaptureKind::ByRef(BorrowKind::Unique | BorrowKind::Mut { .. }) => {
                         FnTrait::FnMut
                     }
@@ -933,7 +933,7 @@ impl InferenceContext<'_> {
         }
         self.minimize_captures();
         let result = mem::take(&mut self.current_captures);
-        let captures = result.into_iter().map(|x| x.with_ty(self)).collect::<Vec<_>>();
+        let captures = result.into_iter().map(|it| it.with_ty(self)).collect::<Vec<_>>();
         self.result.closure_info.insert(closure, (captures, closure_kind));
         closure_kind
     }
@@ -973,20 +973,20 @@ impl InferenceContext<'_> {
     fn sort_closures(&mut self) -> Vec<(ClosureId, Vec<(Ty, Ty, Vec<Ty>, ExprId)>)> {
         let mut deferred_closures = mem::take(&mut self.deferred_closures);
         let mut dependents_count: FxHashMap<ClosureId, usize> =
-            deferred_closures.keys().map(|x| (*x, 0)).collect();
+            deferred_closures.keys().map(|it| (*it, 0)).collect();
         for (_, deps) in &self.closure_dependencies {
             for dep in deps {
                 *dependents_count.entry(*dep).or_default() += 1;
             }
         }
         let mut queue: Vec<_> =
-            deferred_closures.keys().copied().filter(|x| dependents_count[x] == 0).collect();
+            deferred_closures.keys().copied().filter(|it| dependents_count[it] == 0).collect();
         let mut result = vec![];
-        while let Some(x) = queue.pop() {
+        while let Some(it) = queue.pop() {
-            if let Some(d) = deferred_closures.remove(&x) {
+            if let Some(d) = deferred_closures.remove(&it) {
-                result.push((x, d));
+                result.push((it, d));
             }
-            for dep in self.closure_dependencies.get(&x).into_iter().flat_map(|x| x.iter()) {
+            for dep in self.closure_dependencies.get(&it).into_iter().flat_map(|it| it.iter()) {
                 let cnt = dependents_count.get_mut(dep).unwrap();
                 *cnt -= 1;
                 if *cnt == 0 {

crates/hir-ty/src/infer/coerce.rs

@@ -220,7 +220,7 @@ pub(crate) fn coerce(
     Ok((adjustments, table.resolve_with_fallback(ty, &fallback)))
 }
 
-impl<'a> InferenceContext<'a> {
+impl InferenceContext<'_> {
     /// Unify two types, but may coerce the first one to the second one
     /// using "implicit coercion rules" if needed.
     pub(super) fn coerce(
@@ -239,7 +239,7 @@ impl<'a> InferenceContext<'a> {
     }
 }
 
-impl<'a> InferenceTable<'a> {
+impl InferenceTable<'_> {
     /// Unify two types, but may coerce the first one to the second one
     /// using "implicit coercion rules" if needed.
     pub(crate) fn coerce(
@@ -377,7 +377,7 @@ impl<'a> InferenceTable<'a> {
 
         let snapshot = self.snapshot();
 
-        let mut autoderef = Autoderef::new(self, from_ty.clone());
+        let mut autoderef = Autoderef::new(self, from_ty.clone(), false);
         let mut first_error = None;
         let mut found = None;
 

crates/hir-ty/src/infer/expr.rs

@@ -50,7 +50,7 @@ use super::{
     InferenceContext, InferenceDiagnostic, TypeMismatch,
 };
 
-impl<'a> InferenceContext<'a> {
+impl InferenceContext<'_> {
     pub(crate) fn infer_expr(&mut self, tgt_expr: ExprId, expected: &Expectation) -> Ty {
         let ty = self.infer_expr_inner(tgt_expr, expected);
         if let Some(expected_ty) = expected.only_has_type(&mut self.table) {
@@ -316,7 +316,7 @@ impl<'a> InferenceContext<'a> {
             }
             Expr::Call { callee, args, .. } => {
                 let callee_ty = self.infer_expr(*callee, &Expectation::none());
-                let mut derefs = Autoderef::new(&mut self.table, callee_ty.clone());
+                let mut derefs = Autoderef::new(&mut self.table, callee_ty.clone(), false);
                 let (res, derefed_callee) = 'b: {
                     // manual loop to be able to access `derefs.table`
                     while let Some((callee_deref_ty, _)) = derefs.next() {
@@ -928,7 +928,7 @@ impl<'a> InferenceContext<'a> {
                 if let TyKind::Ref(Mutability::Mut, _, inner) = derefed_callee.kind(Interner) {
                     if adjustments
                         .last()
-                        .map(|x| matches!(x.kind, Adjust::Borrow(_)))
+                        .map(|it| matches!(it.kind, Adjust::Borrow(_)))
                         .unwrap_or(true)
                     {
                         // prefer reborrow to move
@@ -1385,7 +1385,7 @@ impl<'a> InferenceContext<'a> {
         receiver_ty: &Ty,
         name: &Name,
     ) -> Option<(Ty, Option<FieldId>, Vec<Adjustment>, bool)> {
-        let mut autoderef = Autoderef::new(&mut self.table, receiver_ty.clone());
+        let mut autoderef = Autoderef::new(&mut self.table, receiver_ty.clone(), false);
         let mut private_field = None;
         let res = autoderef.by_ref().find_map(|(derefed_ty, _)| {
             let (field_id, parameters) = match derefed_ty.kind(Interner) {
@@ -1449,6 +1449,13 @@ impl<'a> InferenceContext<'a> {
 
     fn infer_field_access(&mut self, tgt_expr: ExprId, receiver: ExprId, name: &Name) -> Ty {
         let receiver_ty = self.infer_expr_inner(receiver, &Expectation::none());
+
+        if name.is_missing() {
+            // Bail out early, don't even try to look up field. Also, we don't issue an unresolved
+            // field diagnostic because this is a syntax error rather than a semantic error.
+            return self.err_ty();
+        }
+
         match self.lookup_field(&receiver_ty, name) {
             Some((ty, field_id, adjustments, is_public)) => {
                 self.write_expr_adj(receiver, adjustments);

crates/hir-ty/src/infer/mutability.rs

@@ -12,7 +12,7 @@ use crate::{lower::lower_to_chalk_mutability, Adjust, Adjustment, AutoBorrow, Ov
 
 use super::InferenceContext;
 
-impl<'a> InferenceContext<'a> {
+impl InferenceContext<'_> {
     pub(crate) fn infer_mut_body(&mut self) {
         self.infer_mut_expr(self.body.body_expr, Mutability::Not);
     }
@@ -73,12 +73,12 @@ impl<'a> InferenceContext<'a> {
                 self.infer_mut_expr(c, Mutability::Not);
                 self.infer_mut_expr(body, Mutability::Not);
             }
-            Expr::MethodCall { receiver: x, method_name: _, args, generic_args: _ }
+            Expr::MethodCall { receiver: it, method_name: _, args, generic_args: _ }
-            | Expr::Call { callee: x, args, is_assignee_expr: _ } => {
+            | Expr::Call { callee: it, args, is_assignee_expr: _ } => {
-                self.infer_mut_not_expr_iter(args.iter().copied().chain(Some(*x)));
+                self.infer_mut_not_expr_iter(args.iter().copied().chain(Some(*it)));
             }
             Expr::Match { expr, arms } => {
-                let m = self.pat_iter_bound_mutability(arms.iter().map(|x| x.pat));
+                let m = self.pat_iter_bound_mutability(arms.iter().map(|it| it.pat));
                 self.infer_mut_expr(*expr, m);
                 for arm in arms.iter() {
                     self.infer_mut_expr(arm.expr, Mutability::Not);
@@ -96,7 +96,7 @@ impl<'a> InferenceContext<'a> {
                 }
             }
             Expr::RecordLit { path: _, fields, spread, ellipsis: _, is_assignee_expr: _ } => {
-                self.infer_mut_not_expr_iter(fields.iter().map(|x| x.expr).chain(*spread))
+                self.infer_mut_not_expr_iter(fields.iter().map(|it| it.expr).chain(*spread))
             }
             &Expr::Index { base, index } => {
                 if mutability == Mutability::Mut {
@@ -204,8 +204,8 @@ impl<'a> InferenceContext<'a> {
     }
 
     /// Checks if the pat contains a `ref mut` binding. Such paths makes the context of bounded expressions
-    /// mutable. For example in `let (ref mut x0, ref x1) = *x;` we need to use `DerefMut` for `*x` but in
+    /// mutable. For example in `let (ref mut x0, ref x1) = *it;` we need to use `DerefMut` for `*it` but in
-    /// `let (ref x0, ref x1) = *x;` we should use `Deref`.
+    /// `let (ref x0, ref x1) = *it;` we should use `Deref`.
     fn pat_bound_mutability(&self, pat: PatId) -> Mutability {
         let mut r = Mutability::Not;
         self.body.walk_bindings_in_pat(pat, |b| {

crates/hir-ty/src/infer/pat.rs

@@ -56,7 +56,7 @@ impl PatLike for PatId {
     }
 }
 
-impl<'a> InferenceContext<'a> {
+impl InferenceContext<'_> {
     /// Infers type for tuple struct pattern or its corresponding assignee expression.
     ///
     /// Ellipses found in the original pattern or expression must be filtered out.
@@ -306,7 +306,7 @@ impl<'a> InferenceContext<'a> {
         self.result
             .pat_adjustments
             .get(&pat)
-            .and_then(|x| x.first())
+            .and_then(|it| it.first())
             .unwrap_or(&self.result.type_of_pat[pat])
             .clone()
     }

crates/hir-ty/src/infer/unify.rs

@@ -22,7 +22,7 @@ use crate::{
     TraitEnvironment, Ty, TyBuilder, TyExt, TyKind, VariableKind,
 };
 
-impl<'a> InferenceContext<'a> {
+impl InferenceContext<'_> {
     pub(super) fn canonicalize<T: TypeFoldable<Interner> + HasInterner<Interner = Interner>>(
         &mut self,
         t: T,
@@ -91,7 +91,7 @@ pub(crate) fn unify(
     let mut table = InferenceTable::new(db, env);
     let vars = Substitution::from_iter(
         Interner,
-        tys.binders.iter(Interner).map(|x| match &x.kind {
+        tys.binders.iter(Interner).map(|it| match &it.kind {
             chalk_ir::VariableKind::Ty(_) => {
                 GenericArgData::Ty(table.new_type_var()).intern(Interner)
             }
@@ -547,7 +547,7 @@ impl<'a> InferenceTable<'a> {
             table: &'a mut InferenceTable<'b>,
             highest_known_var: InferenceVar,
         }
-        impl<'a, 'b> TypeFolder<Interner> for VarFudger<'a, 'b> {
+        impl TypeFolder<Interner> for VarFudger<'_, '_> {
             fn as_dyn(&mut self) -> &mut dyn TypeFolder<Interner, Error = Self::Error> {
                 self
             }
@@ -686,8 +686,8 @@ impl<'a> InferenceTable<'a> {
 
         let mut arg_tys = vec![];
         let arg_ty = TyBuilder::tuple(num_args)
-            .fill(|x| {
+            .fill(|it| {
-                let arg = match x {
+                let arg = match it {
                     ParamKind::Type => self.new_type_var(),
                     ParamKind::Const(ty) => {
                         never!("Tuple with const parameter");
@@ -753,7 +753,7 @@ impl<'a> InferenceTable<'a> {
     {
         fold_tys_and_consts(
             ty,
-            |x, _| match x {
+            |it, _| match it {
                 Either::Left(ty) => Either::Left(self.insert_type_vars_shallow(ty)),
                 Either::Right(c) => Either::Right(self.insert_const_vars_shallow(c)),
             },
@@ -798,7 +798,7 @@ impl<'a> InferenceTable<'a> {
     }
 }
 
-impl<'a> fmt::Debug for InferenceTable<'a> {
+impl fmt::Debug for InferenceTable<'_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("InferenceTable").field("num_vars", &self.type_variable_table.len()).finish()
     }
@@ -826,7 +826,7 @@ mod resolve {
         pub(super) var_stack: &'a mut Vec<InferenceVar>,
         pub(super) fallback: F,
     }
-    impl<'a, 'b, F> TypeFolder<Interner> for Resolver<'a, 'b, F>
+    impl<F> TypeFolder<Interner> for Resolver<'_, '_, F>
     where
         F: Fn(InferenceVar, VariableKind, GenericArg, DebruijnIndex) -> GenericArg,
     {

crates/hir-ty/src/layout.rs

@@ -7,7 +7,7 @@ use hir_def::{
         Abi, FieldsShape, Integer, LayoutCalculator, LayoutS, Primitive, ReprOptions, Scalar, Size,
         StructKind, TargetDataLayout, WrappingRange,
     },
-    LocalEnumVariantId, LocalFieldId,
+    LocalEnumVariantId, LocalFieldId, StructId,
 };
 use la_arena::{Idx, RawIdx};
 use stdx::never;
@@ -24,8 +24,8 @@ pub use self::{
 };
 
 macro_rules! user_error {
-    ($x: expr) => {
+    ($it: expr) => {
-        return Err(LayoutError::UserError(format!($x)))
+        return Err(LayoutError::UserError(format!($it)))
     };
 }
 
@@ -77,18 +77,101 @@ impl<'a> LayoutCalculator for LayoutCx<'a> {
     }
 }
 
+// FIXME: move this to the `rustc_abi`.
+fn layout_of_simd_ty(
+    db: &dyn HirDatabase,
+    id: StructId,
+    subst: &Substitution,
+    krate: CrateId,
+    dl: &TargetDataLayout,
+) -> Result<Arc<Layout>, LayoutError> {
+    let fields = db.field_types(id.into());
+
+    // Supported SIMD vectors are homogeneous ADTs with at least one field:
+    //
+    // * #[repr(simd)] struct S(T, T, T, T);
+    // * #[repr(simd)] struct S { it: T, y: T, z: T, w: T }
+    // * #[repr(simd)] struct S([T; 4])
+    //
+    // where T is a primitive scalar (integer/float/pointer).
+
+    let f0_ty = match fields.iter().next() {
+        Some(it) => it.1.clone().substitute(Interner, subst),
+        None => {
+            user_error!("simd type with zero fields");
+        }
+    };
+
+    // The element type and number of elements of the SIMD vector
+    // are obtained from:
+    //
+    // * the element type and length of the single array field, if
+    // the first field is of array type, or
+    //
+    // * the homogeneous field type and the number of fields.
+    let (e_ty, e_len, is_array) = if let TyKind::Array(e_ty, _) = f0_ty.kind(Interner) {
+        // Extract the number of elements from the layout of the array field:
+        let FieldsShape::Array { count, .. } = db.layout_of_ty(f0_ty.clone(), krate)?.fields else {
+            user_error!("Array with non array layout");
+        };
+
+        (e_ty.clone(), count, true)
+    } else {
+        // First ADT field is not an array:
+        (f0_ty, fields.iter().count() as u64, false)
+    };
+
+    // Compute the ABI of the element type:
+    let e_ly = db.layout_of_ty(e_ty, krate)?;
+    let Abi::Scalar(e_abi) = e_ly.abi else {
+        user_error!("simd type with inner non scalar type");
+    };
+
+    // Compute the size and alignment of the vector:
+    let size = e_ly.size.checked_mul(e_len, dl).ok_or(LayoutError::SizeOverflow)?;
+    let align = dl.vector_align(size);
+    let size = size.align_to(align.abi);
+
+    // Compute the placement of the vector fields:
+    let fields = if is_array {
+        FieldsShape::Arbitrary { offsets: [Size::ZERO].into(), memory_index: [0].into() }
+    } else {
+        FieldsShape::Array { stride: e_ly.size, count: e_len }
+    };
+
+    Ok(Arc::new(Layout {
+        variants: Variants::Single { index: struct_variant_idx() },
+        fields,
+        abi: Abi::Vector { element: e_abi, count: e_len },
+        largest_niche: e_ly.largest_niche,
+        size,
+        align,
+    }))
+}
+
 pub fn layout_of_ty_query(
     db: &dyn HirDatabase,
     ty: Ty,
     krate: CrateId,
 ) -> Result<Arc<Layout>, LayoutError> {
-    let Some(target) = db.target_data_layout(krate) else { return Err(LayoutError::TargetLayoutNotAvailable) };
+    let Some(target) = db.target_data_layout(krate) else {
+        return Err(LayoutError::TargetLayoutNotAvailable);
+    };
     let cx = LayoutCx { krate, target: &target };
     let dl = &*cx.current_data_layout();
     let trait_env = Arc::new(TraitEnvironment::empty(krate));
     let ty = normalize(db, trait_env, ty.clone());
     let result = match ty.kind(Interner) {
-        TyKind::Adt(AdtId(def), subst) => return db.layout_of_adt(*def, subst.clone(), krate),
+        TyKind::Adt(AdtId(def), subst) => {
+            if let hir_def::AdtId::StructId(s) = def {
+                let data = db.struct_data(*s);
+                let repr = data.repr.unwrap_or_default();
+                if repr.simd() {
+                    return layout_of_simd_ty(db, *s, subst, krate, &target);
+                }
+            };
+            return db.layout_of_adt(*def, subst.clone(), krate);
+        }
         TyKind::Scalar(s) => match s {
             chalk_ir::Scalar::Bool => Layout::scalar(
                 dl,
@@ -147,7 +230,7 @@ pub fn layout_of_ty_query(
                 .iter(Interner)
                 .map(|k| db.layout_of_ty(k.assert_ty_ref(Interner).clone(), krate))
                 .collect::<Result<Vec<_>, _>>()?;
-            let fields = fields.iter().map(|x| &**x).collect::<Vec<_>>();
+            let fields = fields.iter().map(|it| &**it).collect::<Vec<_>>();
             let fields = fields.iter().collect::<Vec<_>>();
             cx.univariant(dl, &fields, &ReprOptions::default(), kind).ok_or(LayoutError::Unknown)?
         }
@@ -265,14 +348,14 @@ pub fn layout_of_ty_query(
             let (captures, _) = infer.closure_info(c);
             let fields = captures
                 .iter()
-                .map(|x| {
+                .map(|it| {
                     db.layout_of_ty(
-                        x.ty.clone().substitute(Interner, ClosureSubst(subst).parent_subst()),
+                        it.ty.clone().substitute(Interner, ClosureSubst(subst).parent_subst()),
                         krate,
                     )
                 })
                 .collect::<Result<Vec<_>, _>>()?;
-            let fields = fields.iter().map(|x| &**x).collect::<Vec<_>>();
+            let fields = fields.iter().map(|it| &**it).collect::<Vec<_>>();
             let fields = fields.iter().collect::<Vec<_>>();
             cx.univariant(dl, &fields, &ReprOptions::default(), StructKind::AlwaysSized)
                 .ok_or(LayoutError::Unknown)?
@@ -315,7 +398,10 @@ fn struct_tail_erasing_lifetimes(db: &dyn HirDatabase, pointee: Ty) -> Ty {
             let data = db.struct_data(*i);
             let mut it = data.variant_data.fields().iter().rev();
             match it.next() {
-                Some((f, _)) => field_ty(db, (*i).into(), f, subst),
+                Some((f, _)) => {
+                    let last_field_ty = field_ty(db, (*i).into(), f, subst);
+                    struct_tail_erasing_lifetimes(db, last_field_ty)
+                }
                 None => pointee,
             }
         }

crates/hir-ty/src/layout/adt.rs

@@ -31,7 +31,9 @@ pub fn layout_of_adt_query(
     subst: Substitution,
     krate: CrateId,
 ) -> Result<Arc<Layout>, LayoutError> {
-    let Some(target) = db.target_data_layout(krate) else { return Err(LayoutError::TargetLayoutNotAvailable) };
+    let Some(target) = db.target_data_layout(krate) else {
+        return Err(LayoutError::TargetLayoutNotAvailable);
+    };
     let cx = LayoutCx { krate, target: &target };
     let dl = cx.current_data_layout();
     let handle_variant = |def: VariantId, var: &VariantData| {
@@ -70,9 +72,9 @@ pub fn layout_of_adt_query(
     };
     let variants = variants
         .iter()
-        .map(|x| x.iter().map(|x| &**x).collect::<Vec<_>>())
+        .map(|it| it.iter().map(|it| &**it).collect::<Vec<_>>())
         .collect::<SmallVec<[_; 1]>>();
-    let variants = variants.iter().map(|x| x.iter().collect()).collect();
+    let variants = variants.iter().map(|it| it.iter().collect()).collect();
     let result = if matches!(def, AdtId::UnionId(..)) {
         cx.layout_of_union(&repr, &variants).ok_or(LayoutError::Unknown)?
     } else {
@@ -103,7 +105,7 @@ pub fn layout_of_adt_query(
                 && variants
                     .iter()
                     .next()
-                    .and_then(|x| x.last().map(|x| x.is_unsized()))
+                    .and_then(|it| it.last().map(|it| !it.is_unsized()))
                     .unwrap_or(true),
         )
         .ok_or(LayoutError::SizeOverflow)?
@@ -116,9 +118,9 @@ fn layout_scalar_valid_range(db: &dyn HirDatabase, def: AdtId) -> (Bound<u128>,
     let get = |name| {
         let attr = attrs.by_key(name).tt_values();
         for tree in attr {
-            if let Some(x) = tree.token_trees.first() {
+            if let Some(it) = tree.token_trees.first() {
-                if let Ok(x) = x.to_string().parse() {
+                if let Ok(it) = it.to_string().parse() {
-                    return Bound::Included(x);
+                    return Bound::Included(it);
                 }
             }
         }

crates/hir-ty/src/layout/tests.rs

@@ -270,6 +270,20 @@ struct Goal(Foo<S>);
     );
 }
 
+#[test]
+fn simd_types() {
+    check_size_and_align(
+        r#"
+            #[repr(simd)]
+            struct SimdType(i64, i64);
+            struct Goal(SimdType);
+        "#,
+        "",
+        16,
+        16,
+    );
+}
+
 #[test]
 fn return_position_impl_trait() {
     size_and_align_expr! {
@@ -343,6 +357,24 @@ fn return_position_impl_trait() {
     }
 }
 
+#[test]
+fn unsized_ref() {
+    size_and_align! {
+        struct S1([u8]);
+        struct S2(S1);
+        struct S3(i32, str);
+        struct S4(u64, S3);
+        #[allow(dead_code)]
+        struct S5 {
+            field1: u8,
+            field2: i16,
+            field_last: S4,
+        }
+
+        struct Goal(&'static S1, &'static S2, &'static S3, &'static S4, &'static S5);
+    }
+}
+
 #[test]
 fn enums() {
     size_and_align! {
@@ -369,11 +401,11 @@ fn tuple() {
 }
 
 #[test]
-fn non_zero() {
+fn non_zero_and_non_null() {
     size_and_align! {
-        minicore: non_zero, option;
+        minicore: non_zero, non_null, option;
-        use core::num::NonZeroU8;
+        use core::{num::NonZeroU8, ptr::NonNull};
-        struct Goal(Option<NonZeroU8>);
+        struct Goal(Option<NonZeroU8>, Option<NonNull<i32>>);
     }
 }
 
@@ -432,3 +464,41 @@ fn enums_with_discriminants() {
         }
     }
 }
+
+#[test]
+fn core_mem_discriminant() {
+    size_and_align! {
+        minicore: discriminant;
+        struct S(i32, u64);
+        struct Goal(core::mem::Discriminant<S>);
+    }
+    size_and_align! {
+        minicore: discriminant;
+        #[repr(u32)]
+        enum S {
+            A,
+            B,
+            C,
+        }
+        struct Goal(core::mem::Discriminant<S>);
+    }
+    size_and_align! {
+        minicore: discriminant;
+        enum S {
+            A(i32),
+            B(i64),
+            C(u8),
+        }
+        struct Goal(core::mem::Discriminant<S>);
+    }
+    size_and_align! {
+        minicore: discriminant;
+        #[repr(C, u16)]
+        enum S {
+            A(i32),
+            B(i64) = 200,
+            C = 1000,
+        }
+        struct Goal(core::mem::Discriminant<S>);
+    }
+}

crates/hir-ty/src/lib.rs

@@ -180,9 +180,16 @@ impl MemoryMap {
     /// allocator function as `f` and it will return a mapping of old addresses to new addresses.
     fn transform_addresses(
         &self,
-        mut f: impl FnMut(&[u8]) -> Result<usize, MirEvalError>,
+        mut f: impl FnMut(&[u8], usize) -> Result<usize, MirEvalError>,
     ) -> Result<HashMap<usize, usize>, MirEvalError> {
-        self.memory.iter().map(|x| Ok((*x.0, f(x.1)?))).collect()
+        self.memory
+            .iter()
+            .map(|x| {
+                let addr = *x.0;
+                let align = if addr == 0 { 64 } else { (addr - (addr & (addr - 1))).min(64) };
+                Ok((addr, f(x.1, align)?))
+            })
+            .collect()
     }
 
     fn get<'a>(&'a self, addr: usize, size: usize) -> Option<&'a [u8]> {

crates/hir-ty/src/lower.rs

@@ -23,7 +23,7 @@ use hir_def::{
     generics::{
         TypeOrConstParamData, TypeParamProvenance, WherePredicate, WherePredicateTypeTarget,
     },
-    lang_item::{lang_attr, LangItem},
+    lang_item::LangItem,
     nameres::MacroSubNs,
     path::{GenericArg, GenericArgs, ModPath, Path, PathKind, PathSegment, PathSegments},
     resolver::{HasResolver, Resolver, TypeNs},
@@ -959,10 +959,10 @@ impl<'a> TyLoweringContext<'a> {
     }
 
     pub(crate) fn lower_where_predicate(
-        &'a self,
+        &self,
-        where_predicate: &'a WherePredicate,
+        where_predicate: &WherePredicate,
         ignore_bindings: bool,
-    ) -> impl Iterator<Item = QuantifiedWhereClause> + 'a {
+    ) -> impl Iterator<Item = QuantifiedWhereClause> {
         match where_predicate {
             WherePredicate::ForLifetime { target, bound, .. }
             | WherePredicate::TypeBound { target, bound } => {
@@ -1012,7 +1012,7 @@ impl<'a> TyLoweringContext<'a> {
                         //   (So ideally, we'd only ignore `~const Drop` here)
                         // - `Destruct` impls are built-in in 1.62 (current nightly as of 08-04-2022), so until
                         //   the builtin impls are supported by Chalk, we ignore them here.
-                        if let Some(lang) = lang_attr(self.db.upcast(), tr.hir_trait_id()) {
+                        if let Some(lang) = self.db.lang_attr(tr.hir_trait_id().into()) {
                             if matches!(lang, LangItem::Drop | LangItem::Destruct) {
                                 return false;
                             }

crates/hir-ty/src/method_resolution.rs

@@ -534,7 +534,7 @@ impl ReceiverAdjustments {
         let mut ty = table.resolve_ty_shallow(&ty);
         let mut adjust = Vec::new();
         for _ in 0..self.autoderefs {
-            match autoderef::autoderef_step(table, ty.clone()) {
+            match autoderef::autoderef_step(table, ty.clone(), true) {
                 None => {
                     never!("autoderef not possible for {:?}", ty);
                     ty = TyKind::Error.intern(Interner);
@@ -559,10 +559,10 @@ impl ReceiverAdjustments {
             adjust.push(a);
         }
         if self.unsize_array {
-            ty = 'x: {
+            ty = 'it: {
                 if let TyKind::Ref(m, l, inner) = ty.kind(Interner) {
                     if let TyKind::Array(inner, _) = inner.kind(Interner) {
-                        break 'x TyKind::Ref(
+                        break 'it TyKind::Ref(
                             m.clone(),
                             l.clone(),
                             TyKind::Slice(inner.clone()).intern(Interner),
@@ -666,7 +666,7 @@ pub fn is_dyn_method(
     let self_ty = trait_ref.self_type_parameter(Interner);
     if let TyKind::Dyn(d) = self_ty.kind(Interner) {
         let is_my_trait_in_bounds =
-            d.bounds.skip_binders().as_slice(Interner).iter().any(|x| match x.skip_binders() {
+            d.bounds.skip_binders().as_slice(Interner).iter().any(|it| match it.skip_binders() {
                 // rustc doesn't accept `impl Foo<2> for dyn Foo<5>`, so if the trait id is equal, no matter
                 // what the generics are, we are sure that the method is come from the vtable.
                 WhereClause::Implemented(tr) => tr.trait_id == trait_ref.trait_id,
@@ -682,14 +682,14 @@ pub fn is_dyn_method(
 /// Looks up the impl method that actually runs for the trait method `func`.
 ///
 /// Returns `func` if it's not a method defined in a trait or the lookup failed.
-pub fn lookup_impl_method(
+pub(crate) fn lookup_impl_method_query(
     db: &dyn HirDatabase,
     env: Arc<TraitEnvironment>,
     func: FunctionId,
     fn_subst: Substitution,
 ) -> (FunctionId, Substitution) {
     let ItemContainerId::TraitId(trait_id) = func.lookup(db.upcast()).container else {
-        return (func, fn_subst)
+        return (func, fn_subst);
     };
     let trait_params = db.generic_params(trait_id.into()).type_or_consts.len();
     let fn_params = fn_subst.len(Interner) - trait_params;
@@ -699,8 +699,8 @@ pub fn lookup_impl_method(
     };
 
     let name = &db.function_data(func).name;
-    let Some((impl_fn, impl_subst)) = lookup_impl_assoc_item_for_trait_ref(trait_ref, db, env, name)
+    let Some((impl_fn, impl_subst)) =
-        .and_then(|assoc| {
+        lookup_impl_assoc_item_for_trait_ref(trait_ref, db, env, name).and_then(|assoc| {
             if let (AssocItemId::FunctionId(id), subst) = assoc {
                 Some((id, subst))
             } else {
@@ -731,7 +731,7 @@ fn lookup_impl_assoc_item_for_trait_ref(
     let impls = db.trait_impls_in_deps(env.krate);
     let self_impls = match self_ty.kind(Interner) {
         TyKind::Adt(id, _) => {
-            id.0.module(db.upcast()).containing_block().map(|x| db.trait_impls_in_block(x))
+            id.0.module(db.upcast()).containing_block().map(|it| db.trait_impls_in_block(it))
         }
         _ => None,
     };
@@ -895,8 +895,8 @@ pub fn iterate_method_candidates_dyn(
             // (just as rustc does an autoderef and then autoref again).
 
             // We have to be careful about the order we're looking at candidates
-            // in here. Consider the case where we're resolving `x.clone()`
+            // in here. Consider the case where we're resolving `it.clone()`
-            // where `x: &Vec<_>`. This resolves to the clone method with self
+            // where `it: &Vec<_>`. This resolves to the clone method with self
             // type `Vec<_>`, *not* `&_`. I.e. we need to consider methods where
             // the receiver type exactly matches before cases where we have to
             // do autoref. But in the autoderef steps, the `&_` self type comes
@@ -1012,8 +1012,8 @@ fn iterate_method_candidates_by_receiver(
     let snapshot = table.snapshot();
     // We're looking for methods with *receiver* type receiver_ty. These could
     // be found in any of the derefs of receiver_ty, so we have to go through
-    // that.
+    // that, including raw derefs.
-    let mut autoderef = autoderef::Autoderef::new(&mut table, receiver_ty.clone());
+    let mut autoderef = autoderef::Autoderef::new(&mut table, receiver_ty.clone(), true);
     while let Some((self_ty, _)) = autoderef.next() {
         iterate_inherent_methods(
             &self_ty,
@@ -1028,7 +1028,7 @@ fn iterate_method_candidates_by_receiver(
 
     table.rollback_to(snapshot);
 
-    let mut autoderef = autoderef::Autoderef::new(&mut table, receiver_ty.clone());
+    let mut autoderef = autoderef::Autoderef::new(&mut table, receiver_ty.clone(), true);
     while let Some((self_ty, _)) = autoderef.next() {
         iterate_trait_method_candidates(
             &self_ty,
@@ -1480,8 +1480,8 @@ fn generic_implements_goal(
         .push(self_ty.value.clone())
         .fill_with_bound_vars(DebruijnIndex::INNERMOST, kinds.len())
         .build();
-    kinds.extend(trait_ref.substitution.iter(Interner).skip(1).map(|x| {
+    kinds.extend(trait_ref.substitution.iter(Interner).skip(1).map(|it| {
-        let vk = match x.data(Interner) {
+        let vk = match it.data(Interner) {
             chalk_ir::GenericArgData::Ty(_) => {
                 chalk_ir::VariableKind::Ty(chalk_ir::TyVariableKind::General)
             }
@@ -1504,7 +1504,7 @@ fn autoderef_method_receiver(
     ty: Ty,
 ) -> Vec<(Canonical<Ty>, ReceiverAdjustments)> {
     let mut deref_chain: Vec<_> = Vec::new();
-    let mut autoderef = autoderef::Autoderef::new(table, ty);
+    let mut autoderef = autoderef::Autoderef::new(table, ty, true);
     while let Some((ty, derefs)) = autoderef.next() {
         deref_chain.push((
             autoderef.table.canonicalize(ty).value,

crates/hir-ty/src/mir.rs

@@ -3,9 +3,14 @@
 use std::{fmt::Display, iter};
 
 use crate::{
-    consteval::usize_const, db::HirDatabase, display::HirDisplay, infer::PointerCast,
+    consteval::usize_const,
-    lang_items::is_box, mapping::ToChalk, CallableDefId, ClosureId, Const, ConstScalar,
+    db::HirDatabase,
-    InferenceResult, Interner, MemoryMap, Substitution, Ty, TyKind,
+    display::HirDisplay,
+    infer::{normalize, PointerCast},
+    lang_items::is_box,
+    mapping::ToChalk,
+    CallableDefId, ClosureId, Const, ConstScalar, InferenceResult, Interner, MemoryMap,
+    Substitution, TraitEnvironment, Ty, TyKind,
 };
 use base_db::CrateId;
 use chalk_ir::Mutability;
@@ -22,7 +27,9 @@ mod pretty;
 mod monomorphization;
 
 pub use borrowck::{borrowck_query, BorrowckResult, MutabilityReason};
-pub use eval::{interpret_mir, pad16, Evaluator, MirEvalError, VTableMap};
+pub use eval::{
+    interpret_mir, pad16, render_const_using_debug_impl, Evaluator, MirEvalError, VTableMap,
+};
 pub use lower::{
     lower_to_mir, mir_body_for_closure_query, mir_body_query, mir_body_recover, MirLowerError,
 };
@@ -32,6 +39,7 @@ pub use monomorphization::{
 };
 use smallvec::{smallvec, SmallVec};
 use stdx::{impl_from, never};
+use triomphe::Arc;
 
 use super::consteval::{intern_const_scalar, try_const_usize};
 
@@ -129,11 +137,19 @@ pub enum ProjectionElem<V, T> {
 impl<V, T> ProjectionElem<V, T> {
     pub fn projected_ty(
         &self,
-        base: Ty,
+        mut base: Ty,
         db: &dyn HirDatabase,
         closure_field: impl FnOnce(ClosureId, &Substitution, usize) -> Ty,
         krate: CrateId,
     ) -> Ty {
+        if matches!(base.data(Interner).kind, TyKind::Alias(_) | TyKind::AssociatedType(..)) {
+            base = normalize(
+                db,
+                // FIXME: we should get this from caller
+                Arc::new(TraitEnvironment::empty(krate)),
+                base,
+            );
+        }
         match self {
             ProjectionElem::Deref => match &base.data(Interner).kind {
                 TyKind::Raw(_, inner) | TyKind::Ref(_, _, inner) => inner.clone(),
@@ -321,8 +337,8 @@ impl SwitchTargets {
 
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub struct Terminator {
-    span: MirSpan,
+    pub span: MirSpan,
-    kind: TerminatorKind,
+    pub kind: TerminatorKind,
 }
 
 #[derive(Debug, PartialEq, Eq, Clone)]

crates/hir-ty/src/mir/borrowck.rs

@@ -52,7 +52,7 @@ fn all_mir_bodies(
                 let closures = body.closures.clone();
                 Box::new(
                     iter::once(Ok(body))
-                        .chain(closures.into_iter().flat_map(|x| for_closure(db, x))),
+                        .chain(closures.into_iter().flat_map(|it| for_closure(db, it))),
                 )
             }
             Err(e) => Box::new(iter::once(Err(e))),
@@ -62,7 +62,7 @@ fn all_mir_bodies(
         Ok(body) => {
             let closures = body.closures.clone();
             Box::new(
-                iter::once(Ok(body)).chain(closures.into_iter().flat_map(|x| for_closure(db, x))),
+                iter::once(Ok(body)).chain(closures.into_iter().flat_map(|it| for_closure(db, it))),
             )
         }
         Err(e) => Box::new(iter::once(Err(e))),
@@ -171,7 +171,7 @@ fn moved_out_of_ref(db: &dyn HirDatabase, body: &MirBody) -> Vec<MovedOutOfRef>
                 }
                 TerminatorKind::Call { func, args, .. } => {
                     for_operand(func, terminator.span);
-                    args.iter().for_each(|x| for_operand(x, terminator.span));
+                    args.iter().for_each(|it| for_operand(it, terminator.span));
                 }
                 TerminatorKind::Assert { cond, .. } => {
                     for_operand(cond, terminator.span);
@@ -245,7 +245,7 @@ fn ever_initialized_map(
     body: &MirBody,
 ) -> ArenaMap<BasicBlockId, ArenaMap<LocalId, bool>> {
     let mut result: ArenaMap<BasicBlockId, ArenaMap<LocalId, bool>> =
-        body.basic_blocks.iter().map(|x| (x.0, ArenaMap::default())).collect();
+        body.basic_blocks.iter().map(|it| (it.0, ArenaMap::default())).collect();
     fn dfs(
         db: &dyn HirDatabase,
         body: &MirBody,
@@ -271,7 +271,10 @@ fn ever_initialized_map(
             }
         }
         let Some(terminator) = &block.terminator else {
-            never!("Terminator should be none only in construction.\nThe body:\n{}", body.pretty_print(db));
+            never!(
+                "Terminator should be none only in construction.\nThe body:\n{}",
+                body.pretty_print(db)
+            );
             return;
         };
         let targets = match &terminator.kind {
@@ -311,7 +314,7 @@ fn ever_initialized_map(
         result[body.start_block].insert(l, true);
         dfs(db, body, body.start_block, l, &mut result);
     }
-    for l in body.locals.iter().map(|x| x.0) {
+    for l in body.locals.iter().map(|it| it.0) {
         if !result[body.start_block].contains_idx(l) {
             result[body.start_block].insert(l, false);
             dfs(db, body, body.start_block, l, &mut result);
@@ -325,10 +328,10 @@ fn mutability_of_locals(
     body: &MirBody,
 ) -> ArenaMap<LocalId, MutabilityReason> {
     let mut result: ArenaMap<LocalId, MutabilityReason> =
-        body.locals.iter().map(|x| (x.0, MutabilityReason::Not)).collect();
+        body.locals.iter().map(|it| (it.0, MutabilityReason::Not)).collect();
     let mut push_mut_span = |local, span| match &mut result[local] {
         MutabilityReason::Mut { spans } => spans.push(span),
-        x @ MutabilityReason::Not => *x = MutabilityReason::Mut { spans: vec![span] },
+        it @ MutabilityReason::Not => *it = MutabilityReason::Mut { spans: vec![span] },
     };
     let ever_init_maps = ever_initialized_map(db, body);
     for (block_id, mut ever_init_map) in ever_init_maps.into_iter() {

crates/hir-ty/src/mir/eval/shim.rs

@@ -3,20 +3,26 @@
 
 use std::cmp;
 
+use chalk_ir::TyKind;
+use hir_def::resolver::HasResolver;
+use hir_expand::mod_path::ModPath;
+
 use super::*;
 
+mod simd;
+
 macro_rules! from_bytes {
     ($ty:tt, $value:expr) => {
         ($ty::from_le_bytes(match ($value).try_into() {
-            Ok(x) => x,
+            Ok(it) => it,
             Err(_) => return Err(MirEvalError::TypeError("mismatched size")),
         }))
     };
 }
 
 macro_rules! not_supported {
-    ($x: expr) => {
+    ($it: expr) => {
-        return Err(MirEvalError::NotSupported(format!($x)))
+        return Err(MirEvalError::NotSupported(format!($it)))
     };
 }
 
@@ -26,7 +32,7 @@ impl Evaluator<'_> {
         def: FunctionId,
         args: &[IntervalAndTy],
         generic_args: &Substitution,
-        locals: &Locals<'_>,
+        locals: &Locals,
         destination: Interval,
         span: MirSpan,
     ) -> Result<bool> {
@@ -53,6 +59,28 @@ impl Evaluator<'_> {
             )?;
             return Ok(true);
         }
+        let is_platform_intrinsic = match &function_data.abi {
+            Some(abi) => *abi == Interned::new_str("platform-intrinsic"),
+            None => match def.lookup(self.db.upcast()).container {
+                hir_def::ItemContainerId::ExternBlockId(block) => {
+                    let id = block.lookup(self.db.upcast()).id;
+                    id.item_tree(self.db.upcast())[id.value].abi.as_deref()
+                        == Some("platform-intrinsic")
+                }
+                _ => false,
+            },
+        };
+        if is_platform_intrinsic {
+            self.exec_platform_intrinsic(
+                function_data.name.as_text().unwrap_or_default().as_str(),
+                args,
+                generic_args,
+                destination,
+                &locals,
+                span,
+            )?;
+            return Ok(true);
+        }
         let is_extern_c = match def.lookup(self.db.upcast()).container {
             hir_def::ItemContainerId::ExternBlockId(block) => {
                 let id = block.lookup(self.db.upcast()).id;
@@ -74,25 +102,25 @@ impl Evaluator<'_> {
         let alloc_fn = function_data
             .attrs
             .iter()
-            .filter_map(|x| x.path().as_ident())
+            .filter_map(|it| it.path().as_ident())
-            .filter_map(|x| x.as_str())
+            .filter_map(|it| it.as_str())
-            .find(|x| {
+            .find(|it| {
                 [
                     "rustc_allocator",
                     "rustc_deallocator",
                     "rustc_reallocator",
                     "rustc_allocator_zeroed",
                 ]
-                .contains(x)
+                .contains(it)
             });
         if let Some(alloc_fn) = alloc_fn {
             self.exec_alloc_fn(alloc_fn, args, destination)?;
             return Ok(true);
         }
-        if let Some(x) = self.detect_lang_function(def) {
+        if let Some(it) = self.detect_lang_function(def) {
             let arg_bytes =
-                args.iter().map(|x| Ok(x.get(&self)?.to_owned())).collect::<Result<Vec<_>>>()?;
+                args.iter().map(|it| Ok(it.get(&self)?.to_owned())).collect::<Result<Vec<_>>>()?;
-            let result = self.exec_lang_item(x, generic_args, &arg_bytes, locals, span)?;
+            let result = self.exec_lang_item(it, generic_args, &arg_bytes, locals, span)?;
             destination.write_from_bytes(self, &result)?;
             return Ok(true);
         }
@@ -112,7 +140,7 @@ impl Evaluator<'_> {
                 };
                 let size = from_bytes!(usize, size.get(self)?);
                 let align = from_bytes!(usize, align.get(self)?);
-                let result = self.heap_allocate(size, align);
+                let result = self.heap_allocate(size, align)?;
                 destination.write_from_bytes(self, &result.to_bytes())?;
             }
             "rustc_deallocator" => { /* no-op for now */ }
@@ -120,14 +148,18 @@ impl Evaluator<'_> {
                 let [ptr, old_size, align, new_size] = args else {
                     return Err(MirEvalError::TypeError("rustc_allocator args are not provided"));
                 };
-                let ptr = Address::from_bytes(ptr.get(self)?)?;
                 let old_size = from_bytes!(usize, old_size.get(self)?);
                 let new_size = from_bytes!(usize, new_size.get(self)?);
-                let align = from_bytes!(usize, align.get(self)?);
+                if old_size >= new_size {
-                let result = self.heap_allocate(new_size, align);
+                    destination.write_from_interval(self, ptr.interval)?;
-                Interval { addr: result, size: old_size }
+                } else {
-                    .write_from_interval(self, Interval { addr: ptr, size: old_size })?;
+                    let ptr = Address::from_bytes(ptr.get(self)?)?;
-                destination.write_from_bytes(self, &result.to_bytes())?;
+                    let align = from_bytes!(usize, align.get(self)?);
+                    let result = self.heap_allocate(new_size, align)?;
+                    Interval { addr: result, size: old_size }
+                        .write_from_interval(self, Interval { addr: ptr, size: old_size })?;
+                    destination.write_from_bytes(self, &result.to_bytes())?;
+                }
             }
             _ => not_supported!("unknown alloc function"),
         }
@@ -136,7 +168,7 @@ impl Evaluator<'_> {
 
     fn detect_lang_function(&self, def: FunctionId) -> Option<LangItem> {
         use LangItem::*;
-        let candidate = lang_attr(self.db.upcast(), def)?;
+        let candidate = self.db.lang_attr(def.into())?;
         // We want to execute these functions with special logic
         if [PanicFmt, BeginPanic, SliceLen, DropInPlace].contains(&candidate) {
             return Some(candidate);
@@ -146,56 +178,35 @@ impl Evaluator<'_> {
 
     fn exec_lang_item(
         &mut self,
-        x: LangItem,
+        it: LangItem,
         generic_args: &Substitution,
         args: &[Vec<u8>],
-        locals: &Locals<'_>,
+        locals: &Locals,
         span: MirSpan,
     ) -> Result<Vec<u8>> {
         use LangItem::*;
         let mut args = args.iter();
-        match x {
+        match it {
             BeginPanic => Err(MirEvalError::Panic("<unknown-panic-payload>".to_string())),
             PanicFmt => {
                 let message = (|| {
-                    let arguments_struct =
+                    let resolver = self.db.crate_def_map(self.crate_id).crate_root().resolver(self.db.upcast());
-                        self.db.lang_item(self.crate_id, LangItem::FormatArguments)?.as_struct()?;
+                    let Some(format_fn) = resolver.resolve_path_in_value_ns_fully(
-                    let arguments_layout = self
+                        self.db.upcast(),
-                        .layout_adt(arguments_struct.into(), Substitution::empty(Interner))
+                        &hir_def::path::Path::from_known_path_with_no_generic(ModPath::from_segments(
-                        .ok()?;
+                            hir_expand::mod_path::PathKind::Abs,
-                    let arguments_field_pieces =
+                            [name![std], name![fmt], name![format]].into_iter(),
-                        self.db.struct_data(arguments_struct).variant_data.field(&name![pieces])?;
+                        )),
-                    let pieces_offset = arguments_layout
+                    ) else {
-                        .fields
+                        not_supported!("std::fmt::format not found");
-                        .offset(u32::from(arguments_field_pieces.into_raw()) as usize)
+                    };
-                        .bytes_usize();
+                    let hir_def::resolver::ValueNs::FunctionId(format_fn) = format_fn else { not_supported!("std::fmt::format is not a function") };
-                    let ptr_size = self.ptr_size();
+                    let message_string = self.interpret_mir(self.db.mir_body(format_fn.into()).map_err(|e| MirEvalError::MirLowerError(format_fn, e))?, args.map(|x| IntervalOrOwned::Owned(x.clone())))?;
-                    let arg = args.next()?;
+                    let addr = Address::from_bytes(&message_string[self.ptr_size()..2 * self.ptr_size()])?;
-                    let pieces_array_addr =
+                    let size = from_bytes!(usize, message_string[2 * self.ptr_size()..]);
-                        Address::from_bytes(&arg[pieces_offset..pieces_offset + ptr_size]).ok()?;
+                    Ok(std::string::String::from_utf8_lossy(self.read_memory(addr, size)?).into_owned())
-                    let pieces_array_len = usize::from_le_bytes(
-                        (&arg[pieces_offset + ptr_size..pieces_offset + 2 * ptr_size])
-                            .try_into()
-                            .ok()?,
-                    );
-                    let mut message = "".to_string();
-                    for i in 0..pieces_array_len {
-                        let piece_ptr_addr = pieces_array_addr.offset(2 * i * ptr_size);
-                        let piece_addr =
-                            Address::from_bytes(self.read_memory(piece_ptr_addr, ptr_size).ok()?)
-                                .ok()?;
-                        let piece_len = usize::from_le_bytes(
-                            self.read_memory(piece_ptr_addr.offset(ptr_size), ptr_size)
-                                .ok()?
-                                .try_into()
-                                .ok()?,
-                        );
-                        let piece_data = self.read_memory(piece_addr, piece_len).ok()?;
-                        message += &std::string::String::from_utf8_lossy(piece_data);
-                    }
-                    Some(message)
                 })()
-                .unwrap_or_else(|| "<format-args-evaluation-failed>".to_string());
+                .unwrap_or_else(|e| format!("Failed to render panic format args: {e:?}"));
                 Err(MirEvalError::Panic(message))
             }
             SliceLen => {
@@ -207,7 +218,7 @@ impl Evaluator<'_> {
             }
             DropInPlace => {
                 let ty =
-                    generic_args.as_slice(Interner).get(0).and_then(|x| x.ty(Interner)).ok_or(
+                    generic_args.as_slice(Interner).get(0).and_then(|it| it.ty(Interner)).ok_or(
                         MirEvalError::TypeError(
                             "generic argument of drop_in_place is not provided",
                         ),
@@ -224,7 +235,35 @@ impl Evaluator<'_> {
                 )?;
                 Ok(vec![])
             }
-            x => not_supported!("Executing lang item {x:?}"),
+            it => not_supported!("Executing lang item {it:?}"),
+        }
+    }
+
+    fn exec_syscall(
+        &mut self,
+        id: i64,
+        args: &[IntervalAndTy],
+        destination: Interval,
+        _locals: &Locals,
+        _span: MirSpan,
+    ) -> Result<()> {
+        match id {
+            318 => {
+                // SYS_getrandom
+                let [buf, len, _flags] = args else {
+                    return Err(MirEvalError::TypeError("SYS_getrandom args are not provided"));
+                };
+                let addr = Address::from_bytes(buf.get(self)?)?;
+                let size = from_bytes!(usize, len.get(self)?);
+                for i in 0..size {
+                    let rand_byte = self.random_state.rand_u64() as u8;
+                    self.write_memory(addr.offset(i), &[rand_byte])?;
+                }
+                destination.write_from_interval(self, len.interval)
+            }
+            _ => {
+                not_supported!("Unknown syscall id {id:?}")
+            }
         }
     }
 
@@ -234,8 +273,8 @@ impl Evaluator<'_> {
         args: &[IntervalAndTy],
         _generic_args: &Substitution,
         destination: Interval,
-        locals: &Locals<'_>,
+        locals: &Locals,
-        _span: MirSpan,
+        span: MirSpan,
     ) -> Result<()> {
         match as_str {
             "memcmp" => {
@@ -299,7 +338,9 @@ impl Evaluator<'_> {
             }
             "pthread_getspecific" => {
                 let Some(arg0) = args.get(0) else {
-                    return Err(MirEvalError::TypeError("pthread_getspecific arg0 is not provided"));
+                    return Err(MirEvalError::TypeError(
+                        "pthread_getspecific arg0 is not provided",
+                    ));
                 };
                 let key = from_bytes!(usize, &pad16(arg0.get(self)?, false)[0..8]);
                 let value = self.thread_local_storage.get_key(key)?;
@@ -308,11 +349,15 @@ impl Evaluator<'_> {
             }
             "pthread_setspecific" => {
                 let Some(arg0) = args.get(0) else {
-                    return Err(MirEvalError::TypeError("pthread_setspecific arg0 is not provided"));
+                    return Err(MirEvalError::TypeError(
+                        "pthread_setspecific arg0 is not provided",
+                    ));
                 };
                 let key = from_bytes!(usize, &pad16(arg0.get(self)?, false)[0..8]);
                 let Some(arg1) = args.get(1) else {
-                    return Err(MirEvalError::TypeError("pthread_setspecific arg1 is not provided"));
+                    return Err(MirEvalError::TypeError(
+                        "pthread_setspecific arg1 is not provided",
+                    ));
                 };
                 let value = from_bytes!(u128, pad16(arg1.get(self)?, false));
                 self.thread_local_storage.set_key(key, value)?;
@@ -326,17 +371,52 @@ impl Evaluator<'_> {
                 destination.write_from_bytes(self, &0u64.to_le_bytes()[0..destination.size])?;
                 Ok(())
             }
+            "syscall" => {
+                let Some((id, rest)) = args.split_first() else {
+                    return Err(MirEvalError::TypeError(
+                        "syscall arg1 is not provided",
+                    ));
+                };
+                let id = from_bytes!(i64, id.get(self)?);
+                self.exec_syscall(id, rest, destination, locals, span)
+            }
+            "sched_getaffinity" => {
+                let [_pid, _set_size, set] = args else {
+                    return Err(MirEvalError::TypeError("libc::write args are not provided"));
+                };
+                let set = Address::from_bytes(set.get(self)?)?;
+                // Only enable core 0 (we are single threaded anyway), which is bitset 0x0000001
+                self.write_memory(set, &[1])?;
+                // return 0 as success
+                self.write_memory_using_ref(destination.addr, destination.size)?.fill(0);
+                Ok(())
+            }
             _ => not_supported!("unknown external function {as_str}"),
         }
     }
 
+    fn exec_platform_intrinsic(
+        &mut self,
+        name: &str,
+        args: &[IntervalAndTy],
+        generic_args: &Substitution,
+        destination: Interval,
+        locals: &Locals,
+        span: MirSpan,
+    ) -> Result<()> {
+        if let Some(name) = name.strip_prefix("simd_") {
+            return self.exec_simd_intrinsic(name, args, generic_args, destination, locals, span);
+        }
+        not_supported!("unknown platform intrinsic {name}");
+    }
+
     fn exec_intrinsic(
         &mut self,
         name: &str,
         args: &[IntervalAndTy],
         generic_args: &Substitution,
         destination: Interval,
-        locals: &Locals<'_>,
+        locals: &Locals,
         span: MirSpan,
     ) -> Result<()> {
         if let Some(name) = name.strip_prefix("atomic_") {
@@ -347,7 +427,9 @@ impl Evaluator<'_> {
                 "sqrt" | "sin" | "cos" | "exp" | "exp2" | "log" | "log10" | "log2" | "fabs"
                 | "floor" | "ceil" | "trunc" | "rint" | "nearbyint" | "round" | "roundeven" => {
                     let [arg] = args else {
-                        return Err(MirEvalError::TypeError("f64 intrinsic signature doesn't match fn (f64) -> f64"));
+                        return Err(MirEvalError::TypeError(
+                            "f64 intrinsic signature doesn't match fn (f64) -> f64",
+                        ));
                     };
                     let arg = from_bytes!(f64, arg.get(self)?);
                     match name {
@@ -373,7 +455,9 @@ impl Evaluator<'_> {
                 }
                 "pow" | "minnum" | "maxnum" | "copysign" => {
                     let [arg1, arg2] = args else {
-                        return Err(MirEvalError::TypeError("f64 intrinsic signature doesn't match fn (f64, f64) -> f64"));
+                        return Err(MirEvalError::TypeError(
+                            "f64 intrinsic signature doesn't match fn (f64, f64) -> f64",
+                        ));
                     };
                     let arg1 = from_bytes!(f64, arg1.get(self)?);
                     let arg2 = from_bytes!(f64, arg2.get(self)?);
@@ -387,7 +471,9 @@ impl Evaluator<'_> {
                 }
                 "powi" => {
                     let [arg1, arg2] = args else {
-                        return Err(MirEvalError::TypeError("powif64 signature doesn't match fn (f64, i32) -> f64"));
+                        return Err(MirEvalError::TypeError(
+                            "powif64 signature doesn't match fn (f64, i32) -> f64",
+                        ));
                     };
                     let arg1 = from_bytes!(f64, arg1.get(self)?);
                     let arg2 = from_bytes!(i32, arg2.get(self)?);
@@ -395,7 +481,9 @@ impl Evaluator<'_> {
                 }
                 "fma" => {
                     let [arg1, arg2, arg3] = args else {
-                        return Err(MirEvalError::TypeError("fmaf64 signature doesn't match fn (f64, f64, f64) -> f64"));
+                        return Err(MirEvalError::TypeError(
+                            "fmaf64 signature doesn't match fn (f64, f64, f64) -> f64",
+                        ));
                     };
                     let arg1 = from_bytes!(f64, arg1.get(self)?);
                     let arg2 = from_bytes!(f64, arg2.get(self)?);
@@ -411,7 +499,9 @@ impl Evaluator<'_> {
                 "sqrt" | "sin" | "cos" | "exp" | "exp2" | "log" | "log10" | "log2" | "fabs"
                 | "floor" | "ceil" | "trunc" | "rint" | "nearbyint" | "round" | "roundeven" => {
                     let [arg] = args else {
-                        return Err(MirEvalError::TypeError("f32 intrinsic signature doesn't match fn (f32) -> f32"));
+                        return Err(MirEvalError::TypeError(
+                            "f32 intrinsic signature doesn't match fn (f32) -> f32",
+                        ));
                     };
                     let arg = from_bytes!(f32, arg.get(self)?);
                     match name {
@@ -437,7 +527,9 @@ impl Evaluator<'_> {
                 }
                 "pow" | "minnum" | "maxnum" | "copysign" => {
                     let [arg1, arg2] = args else {
-                        return Err(MirEvalError::TypeError("f32 intrinsic signature doesn't match fn (f32, f32) -> f32"));
+                        return Err(MirEvalError::TypeError(
+                            "f32 intrinsic signature doesn't match fn (f32, f32) -> f32",
+                        ));
                     };
                     let arg1 = from_bytes!(f32, arg1.get(self)?);
                     let arg2 = from_bytes!(f32, arg2.get(self)?);
@@ -451,7 +543,9 @@ impl Evaluator<'_> {
                 }
                 "powi" => {
                     let [arg1, arg2] = args else {
-                        return Err(MirEvalError::TypeError("powif32 signature doesn't match fn (f32, i32) -> f32"));
+                        return Err(MirEvalError::TypeError(
+                            "powif32 signature doesn't match fn (f32, i32) -> f32",
+                        ));
                     };
                     let arg1 = from_bytes!(f32, arg1.get(self)?);
                     let arg2 = from_bytes!(i32, arg2.get(self)?);
@@ -459,7 +553,9 @@ impl Evaluator<'_> {
                 }
                 "fma" => {
                     let [arg1, arg2, arg3] = args else {
-                        return Err(MirEvalError::TypeError("fmaf32 signature doesn't match fn (f32, f32, f32) -> f32"));
+                        return Err(MirEvalError::TypeError(
+                            "fmaf32 signature doesn't match fn (f32, f32, f32) -> f32",
+                        ));
                     };
                     let arg1 = from_bytes!(f32, arg1.get(self)?);
                     let arg2 = from_bytes!(f32, arg2.get(self)?);
@@ -472,21 +568,74 @@ impl Evaluator<'_> {
         }
         match name {
             "size_of" => {
-                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|x| x.ty(Interner)) else {
+                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|it| it.ty(Interner))
+                else {
                     return Err(MirEvalError::TypeError("size_of generic arg is not provided"));
                 };
                 let size = self.size_of_sized(ty, locals, "size_of arg")?;
                 destination.write_from_bytes(self, &size.to_le_bytes()[0..destination.size])
             }
             "min_align_of" | "pref_align_of" => {
-                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|x| x.ty(Interner)) else {
+                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|it| it.ty(Interner)) else {
                     return Err(MirEvalError::TypeError("align_of generic arg is not provided"));
                 };
                 let align = self.layout(ty)?.align.abi.bytes();
                 destination.write_from_bytes(self, &align.to_le_bytes()[0..destination.size])
             }
+            "size_of_val" => {
+                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|it| it.ty(Interner))
+                else {
+                    return Err(MirEvalError::TypeError("size_of_val generic arg is not provided"));
+                };
+                let [arg] = args else {
+                    return Err(MirEvalError::TypeError("size_of_val args are not provided"));
+                };
+                if let Some((size, _)) = self.size_align_of(ty, locals)? {
+                    destination.write_from_bytes(self, &size.to_le_bytes())
+                } else {
+                    let metadata = arg.interval.slice(self.ptr_size()..self.ptr_size() * 2);
+                    let (size, _) = self.size_align_of_unsized(ty, metadata, locals)?;
+                    destination.write_from_bytes(self, &size.to_le_bytes())
+                }
+            }
+            "min_align_of_val" => {
+                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|it| it.ty(Interner)) else {
+                    return Err(MirEvalError::TypeError("min_align_of_val generic arg is not provided"));
+                };
+                let [arg] = args else {
+                    return Err(MirEvalError::TypeError("min_align_of_val args are not provided"));
+                };
+                if let Some((_, align)) = self.size_align_of(ty, locals)? {
+                    destination.write_from_bytes(self, &align.to_le_bytes())
+                } else {
+                    let metadata = arg.interval.slice(self.ptr_size()..self.ptr_size() * 2);
+                    let (_, align) = self.size_align_of_unsized(ty, metadata, locals)?;
+                    destination.write_from_bytes(self, &align.to_le_bytes())
+                }
+            }
+            "type_name" => {
+                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|it| it.ty(Interner))
+                else {
+                    return Err(MirEvalError::TypeError("type_name generic arg is not provided"));
+                };
+                let Ok(ty_name) = ty.display_source_code(
+                    self.db,
+                    locals.body.owner.module(self.db.upcast()),
+                    true,
+                ) else {
+                    not_supported!("fail in generating type_name using source code display");
+                };
+                let len = ty_name.len();
+                let addr = self.heap_allocate(len, 1)?;
+                self.write_memory(addr, ty_name.as_bytes())?;
+                destination.slice(0..self.ptr_size()).write_from_bytes(self, &addr.to_bytes())?;
+                destination
+                    .slice(self.ptr_size()..2 * self.ptr_size())
+                    .write_from_bytes(self, &len.to_le_bytes())
+            }
             "needs_drop" => {
-                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|x| x.ty(Interner)) else {
+                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|it| it.ty(Interner))
+                else {
                     return Err(MirEvalError::TypeError("size_of generic arg is not provided"));
                 };
                 let result = !ty.clone().is_copy(self.db, locals.body.owner);
@@ -501,13 +650,17 @@ impl Evaluator<'_> {
                 let ans = lhs.get(self)? == rhs.get(self)?;
                 destination.write_from_bytes(self, &[u8::from(ans)])
             }
-            "saturating_add" => {
+            "saturating_add" | "saturating_sub" => {
                 let [lhs, rhs] = args else {
                     return Err(MirEvalError::TypeError("saturating_add args are not provided"));
                 };
                 let lhs = u128::from_le_bytes(pad16(lhs.get(self)?, false));
                 let rhs = u128::from_le_bytes(pad16(rhs.get(self)?, false));
-                let ans = lhs.saturating_add(rhs);
+                let ans = match name {
+                    "saturating_add" => lhs.saturating_add(rhs),
+                    "saturating_sub" => lhs.saturating_sub(rhs),
+                    _ => unreachable!(),
+                };
                 let bits = destination.size * 8;
                 // FIXME: signed
                 let is_signed = false;
@@ -544,6 +697,26 @@ impl Evaluator<'_> {
                 let ans = lhs.wrapping_mul(rhs);
                 destination.write_from_bytes(self, &ans.to_le_bytes()[0..destination.size])
             }
+            "wrapping_shl" | "unchecked_shl" => {
+                // FIXME: signed
+                let [lhs, rhs] = args else {
+                    return Err(MirEvalError::TypeError("unchecked_shl args are not provided"));
+                };
+                let lhs = u128::from_le_bytes(pad16(lhs.get(self)?, false));
+                let rhs = u128::from_le_bytes(pad16(rhs.get(self)?, false));
+                let ans = lhs.wrapping_shl(rhs as u32);
+                destination.write_from_bytes(self, &ans.to_le_bytes()[0..destination.size])
+            }
+            "wrapping_shr" | "unchecked_shr" => {
+                // FIXME: signed
+                let [lhs, rhs] = args else {
+                    return Err(MirEvalError::TypeError("unchecked_shr args are not provided"));
+                };
+                let lhs = u128::from_le_bytes(pad16(lhs.get(self)?, false));
+                let rhs = u128::from_le_bytes(pad16(rhs.get(self)?, false));
+                let ans = lhs.wrapping_shr(rhs as u32);
+                destination.write_from_bytes(self, &ans.to_le_bytes()[0..destination.size])
+            }
             "unchecked_rem" => {
                 // FIXME: signed
                 let [lhs, rhs] = args else {
@@ -588,7 +761,7 @@ impl Evaluator<'_> {
                     _ => unreachable!(),
                 };
                 let is_overflow = u128overflow
-                    || ans.to_le_bytes()[op_size..].iter().any(|&x| x != 0 && x != 255);
+                    || ans.to_le_bytes()[op_size..].iter().any(|&it| it != 0 && it != 255);
                 let is_overflow = vec![u8::from(is_overflow)];
                 let layout = self.layout(&result_ty)?;
                 let result = self.make_by_layout(
@@ -603,10 +776,15 @@ impl Evaluator<'_> {
             }
             "copy" | "copy_nonoverlapping" => {
                 let [src, dst, offset] = args else {
-                    return Err(MirEvalError::TypeError("copy_nonoverlapping args are not provided"));
+                    return Err(MirEvalError::TypeError(
+                        "copy_nonoverlapping args are not provided",
+                    ));
                 };
-                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|x| x.ty(Interner)) else {
+                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|it| it.ty(Interner))
-                    return Err(MirEvalError::TypeError("copy_nonoverlapping generic arg is not provided"));
+                else {
+                    return Err(MirEvalError::TypeError(
+                        "copy_nonoverlapping generic arg is not provided",
+                    ));
                 };
                 let src = Address::from_bytes(src.get(self)?)?;
                 let dst = Address::from_bytes(dst.get(self)?)?;
@@ -621,7 +799,8 @@ impl Evaluator<'_> {
                 let [ptr, offset] = args else {
                     return Err(MirEvalError::TypeError("offset args are not provided"));
                 };
-                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|x| x.ty(Interner)) else {
+                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|it| it.ty(Interner))
+                else {
                     return Err(MirEvalError::TypeError("offset generic arg is not provided"));
                 };
                 let ptr = u128::from_le_bytes(pad16(ptr.get(self)?, false));
@@ -652,20 +831,106 @@ impl Evaluator<'_> {
             }
             "ctpop" => {
                 let [arg] = args else {
-                    return Err(MirEvalError::TypeError("likely arg is not provided"));
+                    return Err(MirEvalError::TypeError("ctpop arg is not provided"));
                 };
                 let result = u128::from_le_bytes(pad16(arg.get(self)?, false)).count_ones();
                 destination
                     .write_from_bytes(self, &(result as u128).to_le_bytes()[0..destination.size])
             }
+            "ctlz" | "ctlz_nonzero" => {
+                let [arg] = args else {
+                    return Err(MirEvalError::TypeError("cttz arg is not provided"));
+                };
+                let result =
+                    u128::from_le_bytes(pad16(arg.get(self)?, false)).leading_zeros() as usize;
+                let result = result - (128 - arg.interval.size * 8);
+                destination
+                    .write_from_bytes(self, &(result as u128).to_le_bytes()[0..destination.size])
+            }
             "cttz" | "cttz_nonzero" => {
                 let [arg] = args else {
-                    return Err(MirEvalError::TypeError("likely arg is not provided"));
+                    return Err(MirEvalError::TypeError("cttz arg is not provided"));
                 };
                 let result = u128::from_le_bytes(pad16(arg.get(self)?, false)).trailing_zeros();
                 destination
                     .write_from_bytes(self, &(result as u128).to_le_bytes()[0..destination.size])
             }
+            "rotate_left" => {
+                let [lhs, rhs] = args else {
+                    return Err(MirEvalError::TypeError("rotate_left args are not provided"));
+                };
+                let lhs = &lhs.get(self)?[0..destination.size];
+                let rhs = rhs.get(self)?[0] as u32;
+                match destination.size {
+                    1 => {
+                        let r = from_bytes!(u8, lhs).rotate_left(rhs);
+                        destination.write_from_bytes(self, &r.to_le_bytes())
+                    }
+                    2 => {
+                        let r = from_bytes!(u16, lhs).rotate_left(rhs);
+                        destination.write_from_bytes(self, &r.to_le_bytes())
+                    }
+                    4 => {
+                        let r = from_bytes!(u32, lhs).rotate_left(rhs);
+                        destination.write_from_bytes(self, &r.to_le_bytes())
+                    }
+                    8 => {
+                        let r = from_bytes!(u64, lhs).rotate_left(rhs);
+                        destination.write_from_bytes(self, &r.to_le_bytes())
+                    }
+                    16 => {
+                        let r = from_bytes!(u128, lhs).rotate_left(rhs);
+                        destination.write_from_bytes(self, &r.to_le_bytes())
+                    }
+                    s => not_supported!("destination with size {s} for rotate_left"),
+                }
+            }
+            "rotate_right" => {
+                let [lhs, rhs] = args else {
+                    return Err(MirEvalError::TypeError("rotate_right args are not provided"));
+                };
+                let lhs = &lhs.get(self)?[0..destination.size];
+                let rhs = rhs.get(self)?[0] as u32;
+                match destination.size {
+                    1 => {
+                        let r = from_bytes!(u8, lhs).rotate_right(rhs);
+                        destination.write_from_bytes(self, &r.to_le_bytes())
+                    }
+                    2 => {
+                        let r = from_bytes!(u16, lhs).rotate_right(rhs);
+                        destination.write_from_bytes(self, &r.to_le_bytes())
+                    }
+                    4 => {
+                        let r = from_bytes!(u32, lhs).rotate_right(rhs);
+                        destination.write_from_bytes(self, &r.to_le_bytes())
+                    }
+                    8 => {
+                        let r = from_bytes!(u64, lhs).rotate_right(rhs);
+                        destination.write_from_bytes(self, &r.to_le_bytes())
+                    }
+                    16 => {
+                        let r = from_bytes!(u128, lhs).rotate_right(rhs);
+                        destination.write_from_bytes(self, &r.to_le_bytes())
+                    }
+                    s => not_supported!("destination with size {s} for rotate_right"),
+                }
+            }
+            "discriminant_value" => {
+                let [arg] = args else {
+                    return Err(MirEvalError::TypeError("discriminant_value arg is not provided"));
+                };
+                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|it| it.ty(Interner))
+                else {
+                    return Err(MirEvalError::TypeError(
+                        "discriminant_value generic arg is not provided",
+                    ));
+                };
+                let addr = Address::from_bytes(arg.get(self)?)?;
+                let size = self.size_of_sized(ty, locals, "discriminant_value ptr type")?;
+                let interval = Interval { addr, size };
+                let r = self.compute_discriminant(ty.clone(), interval.get(self)?)?;
+                destination.write_from_bytes(self, &r.to_le_bytes()[0..destination.size])
+            }
             "const_eval_select" => {
                 let [tuple, const_fn, _] = args else {
                     return Err(MirEvalError::TypeError("const_eval_select args are not provided"));
@@ -681,24 +946,119 @@ impl Evaluator<'_> {
                     let addr = tuple.interval.addr.offset(offset);
                     args.push(IntervalAndTy::new(addr, field, self, locals)?);
                 }
-                self.exec_fn_trait(&args, destination, locals, span)
+                if let Some(target) = self.db.lang_item(self.crate_id, LangItem::FnOnce) {
+                    if let Some(def) = target
+                        .as_trait()
+                        .and_then(|it| self.db.trait_data(it).method_by_name(&name![call_once]))
+                    {
+                        self.exec_fn_trait(
+                            def,
+                            &args,
+                            // FIXME: wrong for manual impls of `FnOnce`
+                            Substitution::empty(Interner),
+                            locals,
+                            destination,
+                            None,
+                            span,
+                        )?;
+                        return Ok(());
+                    }
+                }
+                not_supported!("FnOnce was not available for executing const_eval_select");
+            }
+            "read_via_copy" | "volatile_load" => {
+                let [arg] = args else {
+                    return Err(MirEvalError::TypeError("read_via_copy args are not provided"));
+                };
+                let addr = Address::from_bytes(arg.interval.get(self)?)?;
+                destination.write_from_interval(self, Interval { addr, size: destination.size })
+            }
+            "write_bytes" => {
+                let [dst, val, count] = args else {
+                    return Err(MirEvalError::TypeError("write_bytes args are not provided"));
+                };
+                let count = from_bytes!(usize, count.get(self)?);
+                let val = from_bytes!(u8, val.get(self)?);
+                let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|it| it.ty(Interner))
+                else {
+                    return Err(MirEvalError::TypeError(
+                        "write_bytes generic arg is not provided",
+                    ));
+                };
+                let dst = Address::from_bytes(dst.get(self)?)?;
+                let size = self.size_of_sized(ty, locals, "copy_nonoverlapping ptr type")?;
+                let size = count * size;
+                self.write_memory_using_ref(dst, size)?.fill(val);
+                Ok(())
             }
             _ => not_supported!("unknown intrinsic {name}"),
         }
     }
 
+    fn size_align_of_unsized(
+        &mut self,
+        ty: &Ty,
+        metadata: Interval,
+        locals: &Locals,
+    ) -> Result<(usize, usize)> {
+        Ok(match ty.kind(Interner) {
+            TyKind::Str => (from_bytes!(usize, metadata.get(self)?), 1),
+            TyKind::Slice(inner) => {
+                let len = from_bytes!(usize, metadata.get(self)?);
+                let (size, align) = self.size_align_of_sized(inner, locals, "slice inner type")?;
+                (size * len, align)
+            }
+            TyKind::Dyn(_) => self.size_align_of_sized(
+                self.vtable_map.ty_of_bytes(metadata.get(self)?)?,
+                locals,
+                "dyn concrete type",
+            )?,
+            TyKind::Adt(id, subst) => {
+                let id = id.0;
+                let layout = self.layout_adt(id, subst.clone())?;
+                let id = match id {
+                    AdtId::StructId(s) => s,
+                    _ => not_supported!("unsized enum or union"),
+                };
+                let field_types = &self.db.field_types(id.into());
+                let last_field_ty =
+                    field_types.iter().rev().next().unwrap().1.clone().substitute(Interner, subst);
+                let sized_part_size =
+                    layout.fields.offset(field_types.iter().count() - 1).bytes_usize();
+                let sized_part_align = layout.align.abi.bytes() as usize;
+                let (unsized_part_size, unsized_part_align) =
+                    self.size_align_of_unsized(&last_field_ty, metadata, locals)?;
+                let align = sized_part_align.max(unsized_part_align) as isize;
+                let size = (sized_part_size + unsized_part_size) as isize;
+                // Must add any necessary padding to `size`
+                // (to make it a multiple of `align`) before returning it.
+                //
+                // Namely, the returned size should be, in C notation:
+                //
+                //   `size + ((size & (align-1)) ? align : 0)`
+                //
+                // emulated via the semi-standard fast bit trick:
+                //
+                //   `(size + (align-1)) & -align`
+                let size = (size + (align - 1)) & (-align);
+                (size as usize, align as usize)
+            }
+            _ => not_supported!("unsized type other than str, slice, struct and dyn"),
+        })
+    }
+
     fn exec_atomic_intrinsic(
         &mut self,
         name: &str,
         args: &[IntervalAndTy],
         generic_args: &Substitution,
         destination: Interval,
-        locals: &Locals<'_>,
+        locals: &Locals,
         _span: MirSpan,
     ) -> Result<()> {
         // We are a single threaded runtime with no UB checking and no optimization, so
         // we can implement these as normal functions.
-        let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|x| x.ty(Interner)) else {
+        let Some(ty) = generic_args.as_slice(Interner).get(0).and_then(|it| it.ty(Interner)) else {
             return Err(MirEvalError::TypeError("atomic intrinsic generic arg is not provided"));
         };
         let Some(arg0) = args.get(0) else {

crates/hir-ty/src/mir/eval/shim/simd.rs

@@ -0,0 +1,177 @@
+//! Shim implementation for simd intrinsics
+
+use std::cmp::Ordering;
+
+use crate::TyKind;
+
+use super::*;
+
+macro_rules! from_bytes {
+    ($ty:tt, $value:expr) => {
+        ($ty::from_le_bytes(match ($value).try_into() {
+            Ok(it) => it,
+            Err(_) => return Err(MirEvalError::TypeError("mismatched size")),
+        }))
+    };
+}
+
+macro_rules! not_supported {
+    ($it: expr) => {
+        return Err(MirEvalError::NotSupported(format!($it)))
+    };
+}
+
+impl Evaluator<'_> {
+    fn detect_simd_ty(&self, ty: &Ty) -> Result<(usize, Ty)> {
+        match ty.kind(Interner) {
+            TyKind::Adt(id, subst) => {
+                let len = match subst.as_slice(Interner).get(1).and_then(|it| it.constant(Interner))
+                {
+                    Some(len) => len,
+                    _ => {
+                        if let AdtId::StructId(id) = id.0 {
+                            let struct_data = self.db.struct_data(id);
+                            let fields = struct_data.variant_data.fields();
+                            let Some((first_field, _)) = fields.iter().next() else {
+                                not_supported!("simd type with no field");
+                            };
+                            let field_ty = self.db.field_types(id.into())[first_field]
+                                .clone()
+                                .substitute(Interner, subst);
+                            return Ok((fields.len(), field_ty));
+                        }
+                        return Err(MirEvalError::TypeError("simd type with no len param"));
+                    }
+                };
+                match try_const_usize(self.db, len) {
+                    Some(len) => {
+                        let Some(ty) = subst.as_slice(Interner).get(0).and_then(|it| it.ty(Interner)) else {
+                            return Err(MirEvalError::TypeError("simd type with no ty param"));
+                        };
+                        Ok((len as usize, ty.clone()))
+                    }
+                    None => Err(MirEvalError::TypeError("simd type with unevaluatable len param")),
+                }
+            }
+            _ => Err(MirEvalError::TypeError("simd type which is not a struct")),
+        }
+    }
+
+    pub(super) fn exec_simd_intrinsic(
+        &mut self,
+        name: &str,
+        args: &[IntervalAndTy],
+        _generic_args: &Substitution,
+        destination: Interval,
+        _locals: &Locals,
+        _span: MirSpan,
+    ) -> Result<()> {
+        match name {
+            "and" | "or" | "xor" => {
+                let [left, right] = args else {
+                    return Err(MirEvalError::TypeError("simd bit op args are not provided"));
+                };
+                let result = left
+                    .get(self)?
+                    .iter()
+                    .zip(right.get(self)?)
+                    .map(|(&it, &y)| match name {
+                        "and" => it & y,
+                        "or" => it | y,
+                        "xor" => it ^ y,
+                        _ => unreachable!(),
+                    })
+                    .collect::<Vec<_>>();
+                destination.write_from_bytes(self, &result)
+            }
+            "eq" | "ne" | "lt" | "le" | "gt" | "ge" => {
+                let [left, right] = args else {
+                    return Err(MirEvalError::TypeError("simd args are not provided"));
+                };
+                let (len, ty) = self.detect_simd_ty(&left.ty)?;
+                let is_signed = matches!(ty.as_builtin(), Some(BuiltinType::Int(_)));
+                let size = left.interval.size / len;
+                let dest_size = destination.size / len;
+                let mut destination_bytes = vec![];
+                let vector = left.get(self)?.chunks(size).zip(right.get(self)?.chunks(size));
+                for (l, r) in vector {
+                    let mut result = Ordering::Equal;
+                    for (l, r) in l.iter().zip(r).rev() {
+                        let it = l.cmp(r);
+                        if it != Ordering::Equal {
+                            result = it;
+                            break;
+                        }
+                    }
+                    if is_signed {
+                        if let Some((&l, &r)) = l.iter().zip(r).rev().next() {
+                            if l != r {
+                                result = (l as i8).cmp(&(r as i8));
+                            }
+                        }
+                    }
+                    let result = match result {
+                        Ordering::Less => ["lt", "le", "ne"].contains(&name),
+                        Ordering::Equal => ["ge", "le", "eq"].contains(&name),
+                        Ordering::Greater => ["ge", "gt", "ne"].contains(&name),
+                    };
+                    let result = if result { 255 } else { 0 };
+                    destination_bytes.extend(std::iter::repeat(result).take(dest_size));
+                }
+
+                destination.write_from_bytes(self, &destination_bytes)
+            }
+            "bitmask" => {
+                let [op] = args else {
+                    return Err(MirEvalError::TypeError("simd_bitmask args are not provided"));
+                };
+                let (op_len, _) = self.detect_simd_ty(&op.ty)?;
+                let op_count = op.interval.size / op_len;
+                let mut result: u64 = 0;
+                for (i, val) in op.get(self)?.chunks(op_count).enumerate() {
+                    if !val.iter().all(|&it| it == 0) {
+                        result |= 1 << i;
+                    }
+                }
+                destination.write_from_bytes(self, &result.to_le_bytes()[0..destination.size])
+            }
+            "shuffle" => {
+                let [left, right, index] = args else {
+                    return Err(MirEvalError::TypeError("simd_shuffle args are not provided"));
+                };
+                let TyKind::Array(_, index_len) = index.ty.kind(Interner) else {
+                    return Err(MirEvalError::TypeError(
+                        "simd_shuffle index argument has non-array type",
+                    ));
+                };
+                let index_len = match try_const_usize(self.db, index_len) {
+                    Some(it) => it as usize,
+                    None => {
+                        return Err(MirEvalError::TypeError(
+                            "simd type with unevaluatable len param",
+                        ))
+                    }
+                };
+                let (left_len, _) = self.detect_simd_ty(&left.ty)?;
+                let left_size = left.interval.size / left_len;
+                let vector =
+                    left.get(self)?.chunks(left_size).chain(right.get(self)?.chunks(left_size));
+                let mut result = vec![];
+                for index in index.get(self)?.chunks(index.interval.size / index_len) {
+                    let index = from_bytes!(u32, index) as usize;
+                    let val = match vector.clone().nth(index) {
+                        Some(it) => it,
+                        None => {
+                            return Err(MirEvalError::TypeError(
+                                "out of bound access in simd shuffle",
+                            ))
+                        }
+                    };
+                    result.extend(val);
+                }
+                destination.write_from_bytes(self, &result)
+            }
+            _ => not_supported!("unknown simd intrinsic {name}"),
+        }
+    }
+}

crates/hir-ty/src/mir/eval/tests.rs

@@ -30,7 +30,7 @@ fn eval_main(db: &TestDB, file_id: FileId) -> Result<(String, String), MirEvalEr
             db.trait_environment(func_id.into()),
         )
         .map_err(|e| MirEvalError::MirLowerError(func_id.into(), e))?;
-    let (result, stdout, stderr) = interpret_mir(db, &body, false);
+    let (result, stdout, stderr) = interpret_mir(db, body, false);
     result?;
     Ok((stdout, stderr))
 }
@@ -613,6 +613,34 @@ fn main() {
     );
 }
 
+#[test]
+fn syscalls() {
+    check_pass(
+        r#"
+//- minicore: option
+
+extern "C" {
+    pub unsafe extern "C" fn syscall(num: i64, ...) -> i64;
+}
+
+const SYS_getrandom: i64 = 318;
+
+fn should_not_reach() {
+    _ // FIXME: replace this function with panic when that works
+}
+
+fn main() {
+    let mut x: i32 = 0;
+    let r = syscall(SYS_getrandom, &mut x, 4usize, 0);
+    if r != 4 {
+        should_not_reach();
+    }
+}
+
+"#,
+    )
+}
+
 #[test]
 fn posix_tls() {
     check_pass(

crates/hir-ty/src/mir/lower/as_place.rs

@@ -1,12 +1,12 @@
 //! MIR lowering for places
 
 use super::*;
-use hir_def::{lang_item::lang_attr, FunctionId};
+use hir_def::FunctionId;
 use hir_expand::name;
 
 macro_rules! not_supported {
-    ($x: expr) => {
+    ($it: expr) => {
-        return Err(MirLowerError::NotSupported(format!($x)))
+        return Err(MirLowerError::NotSupported(format!($it)))
     };
 }
 
@@ -18,7 +18,9 @@ impl MirLowerCtx<'_> {
     ) -> Result<Option<(Place, BasicBlockId)>> {
         let ty = self.expr_ty_without_adjust(expr_id);
         let place = self.temp(ty, prev_block, expr_id.into())?;
-        let Some(current) = self.lower_expr_to_place_without_adjust(expr_id, place.into(), prev_block)? else {
+        let Some(current) =
+            self.lower_expr_to_place_without_adjust(expr_id, place.into(), prev_block)?
+        else {
             return Ok(None);
         };
         Ok(Some((place.into(), current)))
@@ -32,10 +34,12 @@ impl MirLowerCtx<'_> {
     ) -> Result<Option<(Place, BasicBlockId)>> {
         let ty = adjustments
             .last()
-            .map(|x| x.target.clone())
+            .map(|it| it.target.clone())
             .unwrap_or_else(|| self.expr_ty_without_adjust(expr_id));
         let place = self.temp(ty, prev_block, expr_id.into())?;
-        let Some(current) = self.lower_expr_to_place_with_adjust(expr_id, place.into(), prev_block, adjustments)? else {
+        let Some(current) =
+            self.lower_expr_to_place_with_adjust(expr_id, place.into(), prev_block, adjustments)?
+        else {
             return Ok(None);
         };
         Ok(Some((place.into(), current)))
@@ -57,16 +61,17 @@ impl MirLowerCtx<'_> {
         if let Some((last, rest)) = adjustments.split_last() {
             match last.kind {
                 Adjust::Deref(None) => {
-                    let Some(mut x) = self.lower_expr_as_place_with_adjust(
+                    let Some(mut it) = self.lower_expr_as_place_with_adjust(
                         current,
                         expr_id,
                         upgrade_rvalue,
                         rest,
-                    )? else {
+                    )?
+                    else {
                         return Ok(None);
                     };
-                    x.0 = x.0.project(ProjectionElem::Deref);
+                    it.0 = it.0.project(ProjectionElem::Deref);
-                    Ok(Some(x))
+                    Ok(Some(it))
                 }
                 Adjust::Deref(Some(od)) => {
                     let Some((r, current)) = self.lower_expr_as_place_with_adjust(
@@ -74,14 +79,15 @@ impl MirLowerCtx<'_> {
                         expr_id,
                         upgrade_rvalue,
                         rest,
-                    )? else {
+                    )?
+                    else {
                         return Ok(None);
                     };
                     self.lower_overloaded_deref(
                         current,
                         r,
                         rest.last()
-                            .map(|x| x.target.clone())
+                            .map(|it| it.target.clone())
                             .unwrap_or_else(|| self.expr_ty_without_adjust(expr_id)),
                         last.target.clone(),
                         expr_id.into(),
@@ -156,7 +162,7 @@ impl MirLowerCtx<'_> {
                     let is_builtin = match self.expr_ty_without_adjust(*expr).kind(Interner) {
                         TyKind::Ref(..) | TyKind::Raw(..) => true,
                         TyKind::Adt(id, _) => {
-                            if let Some(lang_item) = lang_attr(self.db.upcast(), id.0) {
+                            if let Some(lang_item) = self.db.lang_attr(id.0.into()) {
                                 lang_item == LangItem::OwnedBox
                             } else {
                                 false
@@ -165,7 +171,8 @@ impl MirLowerCtx<'_> {
                         _ => false,
                     };
                     if !is_builtin {
-                        let Some((p, current)) = self.lower_expr_as_place(current, *expr, true)? else {
+                        let Some((p, current)) = self.lower_expr_as_place(current, *expr, true)?
+                        else {
                             return Ok(None);
                         };
                         return self.lower_overloaded_deref(
@@ -192,7 +199,8 @@ impl MirLowerCtx<'_> {
                             },
                         );
                     }
-                    let Some((mut r, current)) = self.lower_expr_as_place(current, *expr, true)? else {
+                    let Some((mut r, current)) = self.lower_expr_as_place(current, *expr, true)?
+                    else {
                         return Ok(None);
                     };
                     r = r.project(ProjectionElem::Deref);
@@ -217,12 +225,18 @@ impl MirLowerCtx<'_> {
                     )
                 {
                     let Some(index_fn) = self.infer.method_resolution(expr_id) else {
-                        return Err(MirLowerError::UnresolvedMethod("[overloaded index]".to_string()));
+                        return Err(MirLowerError::UnresolvedMethod(
+                            "[overloaded index]".to_string(),
+                        ));
                     };
-                    let Some((base_place, current)) = self.lower_expr_as_place(current, *base, true)? else {
+                    let Some((base_place, current)) =
+                        self.lower_expr_as_place(current, *base, true)?
+                    else {
                         return Ok(None);
                     };
-                    let Some((index_operand, current)) = self.lower_expr_to_some_operand(*index, current)? else {
+                    let Some((index_operand, current)) =
+                        self.lower_expr_to_some_operand(*index, current)?
+                    else {
                         return Ok(None);
                     };
                     return self.lower_overloaded_index(
@@ -239,8 +253,8 @@ impl MirLowerCtx<'_> {
                     .infer
                     .expr_adjustments
                     .get(base)
-                    .and_then(|x| x.split_last())
+                    .and_then(|it| it.split_last())
-                    .map(|x| x.1)
+                    .map(|it| it.1)
                     .unwrap_or(&[]);
                 let Some((mut p_base, current)) =
                     self.lower_expr_as_place_with_adjust(current, *base, true, adjusts)?
@@ -249,7 +263,8 @@ impl MirLowerCtx<'_> {
                 };
                 let l_index =
                     self.temp(self.expr_ty_after_adjustments(*index), current, expr_id.into())?;
-                let Some(current) = self.lower_expr_to_place(*index, l_index.into(), current)? else {
+                let Some(current) = self.lower_expr_to_place(*index, l_index.into(), current)?
+                else {
                     return Ok(None);
                 };
                 p_base = p_base.project(ProjectionElem::Index(l_index));
@@ -282,7 +297,15 @@ impl MirLowerCtx<'_> {
             )
             .intern(Interner),
         );
-        let Some(current) = self.lower_call(index_fn_op, Box::new([Operand::Copy(place), index_operand]), result.clone(), current, false, span)? else {
+        let Some(current) = self.lower_call(
+            index_fn_op,
+            Box::new([Operand::Copy(place), index_operand]),
+            result.clone(),
+            current,
+            false,
+            span,
+        )?
+        else {
             return Ok(None);
         };
         result = result.project(ProjectionElem::Deref);
@@ -329,7 +352,15 @@ impl MirLowerCtx<'_> {
             .intern(Interner),
         );
         let mut result: Place = self.temp(target_ty_ref, current, span)?.into();
-        let Some(current) = self.lower_call(deref_fn_op, Box::new([Operand::Copy(ref_place)]), result.clone(), current, false, span)? else {
+        let Some(current) = self.lower_call(
+            deref_fn_op,
+            Box::new([Operand::Copy(ref_place)]),
+            result.clone(),
+            current,
+            false,
+            span,
+        )?
+        else {
             return Ok(None);
         };
         result = result.project(ProjectionElem::Deref);

crates/hir-ty/src/mir/lower/pattern_matching.rs

@@ -307,6 +307,11 @@ impl MirLowerCtx<'_> {
                     mode,
                 )?,
                 None => {
+                    // The path is not a variant, so it is a const
+                    if mode != MatchingMode::Check {
+                        // A const don't bind anything. Only needs check.
+                        return Ok((current, current_else));
+                    }
                     let unresolved_name = || MirLowerError::unresolved_path(self.db, p);
                     let resolver = self.owner.resolver(self.db.upcast());
                     let pr = resolver
@@ -362,8 +367,8 @@ impl MirLowerCtx<'_> {
             },
             Pat::Lit(l) => match &self.body.exprs[*l] {
                 Expr::Literal(l) => {
-                    let c = self.lower_literal_to_operand(self.infer[pattern].clone(), l)?;
                     if mode == MatchingMode::Check {
+                        let c = self.lower_literal_to_operand(self.infer[pattern].clone(), l)?;
                         self.pattern_match_const(current_else, current, c, cond_place, pattern)?
                     } else {
                         (current, current_else)

crates/hir-ty/src/mir/monomorphization.rs

@@ -13,15 +13,14 @@ use chalk_ir::{
     fold::{FallibleTypeFolder, TypeFoldable, TypeSuperFoldable},
     ConstData, DebruijnIndex,
 };
-use hir_def::{DefWithBodyId, GeneralConstId};
+use hir_def::DefWithBodyId;
 use triomphe::Arc;
 
 use crate::{
-    consteval::unknown_const,
+    consteval::{intern_const_scalar, unknown_const},
     db::HirDatabase,
     from_placeholder_idx,
     infer::normalize,
-    method_resolution::lookup_impl_const,
     utils::{generics, Generics},
     ClosureId, Const, Interner, ProjectionTy, Substitution, TraitEnvironment, Ty, TyKind,
 };
@@ -29,8 +28,8 @@ use crate::{
 use super::{MirBody, MirLowerError, Operand, Rvalue, StatementKind, TerminatorKind};
 
 macro_rules! not_supported {
-    ($x: expr) => {
+    ($it: expr) => {
-        return Err(MirLowerError::NotSupported(format!($x)))
+        return Err(MirLowerError::NotSupported(format!($it)))
     };
 }
 
@@ -97,16 +96,16 @@ impl FallibleTypeFolder<Interner> for Filler<'_> {
         idx: chalk_ir::PlaceholderIndex,
         _outer_binder: DebruijnIndex,
     ) -> std::result::Result<chalk_ir::Const<Interner>, Self::Error> {
-        let x = from_placeholder_idx(self.db, idx);
+        let it = from_placeholder_idx(self.db, idx);
-        let Some(idx) = self.generics.as_ref().and_then(|g| g.param_idx(x)) else {
+        let Some(idx) = self.generics.as_ref().and_then(|g| g.param_idx(it)) else {
             not_supported!("missing idx in generics");
         };
         Ok(self
             .subst
             .as_slice(Interner)
             .get(idx)
-            .and_then(|x| x.constant(Interner))
+            .and_then(|it| it.constant(Interner))
-            .ok_or_else(|| MirLowerError::GenericArgNotProvided(x, self.subst.clone()))?
+            .ok_or_else(|| MirLowerError::GenericArgNotProvided(it, self.subst.clone()))?
             .clone())
     }
 
@@ -115,16 +114,16 @@ impl FallibleTypeFolder<Interner> for Filler<'_> {
         idx: chalk_ir::PlaceholderIndex,
         _outer_binder: DebruijnIndex,
     ) -> std::result::Result<Ty, Self::Error> {
-        let x = from_placeholder_idx(self.db, idx);
+        let it = from_placeholder_idx(self.db, idx);
-        let Some(idx) = self.generics.as_ref().and_then(|g| g.param_idx(x)) else {
+        let Some(idx) = self.generics.as_ref().and_then(|g| g.param_idx(it)) else {
             not_supported!("missing idx in generics");
         };
         Ok(self
             .subst
             .as_slice(Interner)
             .get(idx)
-            .and_then(|x| x.ty(Interner))
+            .and_then(|it| it.ty(Interner))
-            .ok_or_else(|| MirLowerError::GenericArgNotProvided(x, self.subst.clone()))?
+            .ok_or_else(|| MirLowerError::GenericArgNotProvided(it, self.subst.clone()))?
             .clone())
     }
 
@@ -180,7 +179,7 @@ impl Filler<'_> {
                                 MirLowerError::GenericArgNotProvided(
                                     self.generics
                                         .as_ref()
-                                        .and_then(|x| x.iter().nth(b.index))
+                                        .and_then(|it| it.iter().nth(b.index))
                                         .unwrap()
                                         .0,
                                     self.subst.clone(),
@@ -193,25 +192,12 @@ impl Filler<'_> {
                     | chalk_ir::ConstValue::Placeholder(_) => {}
                     chalk_ir::ConstValue::Concrete(cc) => match &cc.interned {
                         crate::ConstScalar::UnevaluatedConst(const_id, subst) => {
-                            let mut const_id = *const_id;
                             let mut subst = subst.clone();
                             self.fill_subst(&mut subst)?;
-                            if let GeneralConstId::ConstId(c) = const_id {
+                            *c = intern_const_scalar(
-                                let (c, s) = lookup_impl_const(
+                                crate::ConstScalar::UnevaluatedConst(*const_id, subst),
-                                    self.db,
+                                c.data(Interner).ty.clone(),
-                                    self.db.trait_environment_for_body(self.owner),
+                            );
-                                    c,
-                                    subst,
-                                );
-                                const_id = GeneralConstId::ConstId(c);
-                                subst = s;
-                            }
-                            let result =
-                                self.db.const_eval(const_id.into(), subst).map_err(|e| {
-                                    let name = const_id.name(self.db.upcast());
-                                    MirLowerError::ConstEvalError(name, Box::new(e))
-                                })?;
-                            *c = result;
                         }
                         crate::ConstScalar::Bytes(_, _) | crate::ConstScalar::Unknown => (),
                     },

crates/hir-ty/src/mir/pretty.rs

@@ -135,7 +135,7 @@ impl<'a> MirPrettyCtx<'a> {
 
     fn for_closure(&mut self, closure: ClosureId) {
         let body = match self.db.mir_body_for_closure(closure) {
-            Ok(x) => x,
+            Ok(it) => it,
             Err(e) => {
                 wln!(self, "// error in {closure:?}: {e:?}");
                 return;
@@ -145,7 +145,7 @@ impl<'a> MirPrettyCtx<'a> {
         let indent = mem::take(&mut self.indent);
         let mut ctx = MirPrettyCtx {
             body: &body,
-            local_to_binding: body.binding_locals.iter().map(|(x, y)| (*y, x)).collect(),
+            local_to_binding: body.binding_locals.iter().map(|(it, y)| (*y, it)).collect(),
             result,
             indent,
             ..*self
@@ -167,7 +167,7 @@ impl<'a> MirPrettyCtx<'a> {
     }
 
     fn new(body: &'a MirBody, hir_body: &'a Body, db: &'a dyn HirDatabase) -> Self {
-        let local_to_binding = body.binding_locals.iter().map(|(x, y)| (*y, x)).collect();
+        let local_to_binding = body.binding_locals.iter().map(|(it, y)| (*y, it)).collect();
         MirPrettyCtx {
             body,
             db,
@@ -315,17 +315,17 @@ impl<'a> MirPrettyCtx<'a> {
                         }
                     }
                 }
-                ProjectionElem::TupleOrClosureField(x) => {
+                ProjectionElem::TupleOrClosureField(it) => {
                     f(this, local, head);
-                    w!(this, ".{}", x);
+                    w!(this, ".{}", it);
                 }
                 ProjectionElem::Index(l) => {
                     f(this, local, head);
                     w!(this, "[{}]", this.local_name(*l).display(this.db));
                 }
-                x => {
+                it => {
                     f(this, local, head);
-                    w!(this, ".{:?}", x);
+                    w!(this, ".{:?}", it);
                 }
             }
         }
@@ -356,14 +356,14 @@ impl<'a> MirPrettyCtx<'a> {
                 }
                 self.place(p);
             }
-            Rvalue::Aggregate(AggregateKind::Tuple(_), x) => {
+            Rvalue::Aggregate(AggregateKind::Tuple(_), it) => {
                 w!(self, "(");
-                self.operand_list(x);
+                self.operand_list(it);
                 w!(self, ")");
             }
-            Rvalue::Aggregate(AggregateKind::Array(_), x) => {
+            Rvalue::Aggregate(AggregateKind::Array(_), it) => {
                 w!(self, "[");
-                self.operand_list(x);
+                self.operand_list(it);
                 w!(self, "]");
             }
             Rvalue::Repeat(op, len) => {
@@ -371,19 +371,19 @@ impl<'a> MirPrettyCtx<'a> {
                 self.operand(op);
                 w!(self, "; {}]", len.display(self.db));
             }
-            Rvalue::Aggregate(AggregateKind::Adt(_, _), x) => {
+            Rvalue::Aggregate(AggregateKind::Adt(_, _), it) => {
                 w!(self, "Adt(");
-                self.operand_list(x);
+                self.operand_list(it);
                 w!(self, ")");
             }
-            Rvalue::Aggregate(AggregateKind::Closure(_), x) => {
+            Rvalue::Aggregate(AggregateKind::Closure(_), it) => {
                 w!(self, "Closure(");
-                self.operand_list(x);
+                self.operand_list(it);
                 w!(self, ")");
             }
-            Rvalue::Aggregate(AggregateKind::Union(_, _), x) => {
+            Rvalue::Aggregate(AggregateKind::Union(_, _), it) => {
                 w!(self, "Union(");
-                self.operand_list(x);
+                self.operand_list(it);
                 w!(self, ")");
             }
             Rvalue::Len(p) => {
@@ -428,8 +428,8 @@ impl<'a> MirPrettyCtx<'a> {
         }
     }
 
-    fn operand_list(&mut self, x: &[Operand]) {
+    fn operand_list(&mut self, it: &[Operand]) {
-        let mut it = x.iter();
+        let mut it = it.iter();
         if let Some(first) = it.next() {
             self.operand(first);
             for op in it {

crates/hir-ty/src/tests.rs

@@ -30,7 +30,7 @@ use syntax::{
     ast::{self, AstNode, HasName},
     SyntaxNode,
 };
-use tracing_subscriber::{layer::SubscriberExt, EnvFilter, Registry};
+use tracing_subscriber::{layer::SubscriberExt, Registry};
 use tracing_tree::HierarchicalLayer;
 use triomphe::Arc;
 
@@ -52,7 +52,8 @@ fn setup_tracing() -> Option<tracing::subscriber::DefaultGuard> {
         return None;
     }
 
-    let filter = EnvFilter::from_env("CHALK_DEBUG");
+    let filter: tracing_subscriber::filter::Targets =
+        env::var("CHALK_DEBUG").ok().and_then(|it| it.parse().ok()).unwrap_or_default();
     let layer = HierarchicalLayer::default()
         .with_indent_lines(true)
         .with_ansi(false)
@@ -205,7 +206,9 @@ fn check_impl(ra_fixture: &str, allow_none: bool, only_types: bool, display_sour
             let Some(node) = (match expr_or_pat {
                 hir_def::hir::ExprOrPatId::ExprId(expr) => expr_node(&body_source_map, expr, &db),
                 hir_def::hir::ExprOrPatId::PatId(pat) => pat_node(&body_source_map, pat, &db),
-            }) else { continue; };
+            }) else {
+                continue;
+            };
             let range = node.as_ref().original_file_range(&db);
             let actual = format!(
                 "expected {}, got {}",

crates/hir-ty/src/tests/macros.rs

@@ -202,11 +202,11 @@ fn expr_macro_def_expanded_in_various_places() {
             100..119 'for _ ...!() {}': IntoIterator::IntoIter<isize>
             100..119 'for _ ...!() {}': &mut IntoIterator::IntoIter<isize>
             100..119 'for _ ...!() {}': fn next<IntoIterator::IntoIter<isize>>(&mut IntoIterator::IntoIter<isize>) -> Option<<IntoIterator::IntoIter<isize> as Iterator>::Item>
-            100..119 'for _ ...!() {}': Option<Iterator::Item<IntoIterator::IntoIter<isize>>>
+            100..119 'for _ ...!() {}': Option<IntoIterator::Item<isize>>
             100..119 'for _ ...!() {}': ()
             100..119 'for _ ...!() {}': ()
             100..119 'for _ ...!() {}': ()
-            104..105 '_': Iterator::Item<IntoIterator::IntoIter<isize>>
+            104..105 '_': IntoIterator::Item<isize>
             117..119 '{}': ()
             124..134 '|| spam!()': impl Fn() -> isize
             140..156 'while ...!() {}': ()
@@ -293,11 +293,11 @@ fn expr_macro_rules_expanded_in_various_places() {
             114..133 'for _ ...!() {}': IntoIterator::IntoIter<isize>
             114..133 'for _ ...!() {}': &mut IntoIterator::IntoIter<isize>
             114..133 'for _ ...!() {}': fn next<IntoIterator::IntoIter<isize>>(&mut IntoIterator::IntoIter<isize>) -> Option<<IntoIterator::IntoIter<isize> as Iterator>::Item>
-            114..133 'for _ ...!() {}': Option<Iterator::Item<IntoIterator::IntoIter<isize>>>
+            114..133 'for _ ...!() {}': Option<IntoIterator::Item<isize>>
             114..133 'for _ ...!() {}': ()
             114..133 'for _ ...!() {}': ()
             114..133 'for _ ...!() {}': ()
-            118..119 '_': Iterator::Item<IntoIterator::IntoIter<isize>>
+            118..119 '_': IntoIterator::Item<isize>
             131..133 '{}': ()
             138..148 '|| spam!()': impl Fn() -> isize
             154..170 'while ...!() {}': ()

crates/hir-ty/src/tests/method_resolution.rs

@@ -1215,6 +1215,52 @@ fn main() {
     );
 }
 
+#[test]
+fn inherent_method_deref_raw() {
+    check_types(
+        r#"
+struct Val;
+
+impl Val {
+    pub fn method(self: *const Val) -> u32 {
+        0
+    }
+}
+
+fn main() {
+    let foo: *const Val;
+    foo.method();
+ // ^^^^^^^^^^^^ u32
+}
+"#,
+    );
+}
+
+#[test]
+fn trait_method_deref_raw() {
+    check_types(
+        r#"
+trait Trait {
+    fn method(self: *const Self) -> u32;
+}
+
+struct Val;
+
+impl Trait for Val {
+    fn method(self: *const Self) -> u32 {
+        0
+    }
+}
+
+fn main() {
+    let foo: *const Val;
+    foo.method();
+ // ^^^^^^^^^^^^ u32
+}
+"#,
+    );
+}
+
 #[test]
 fn method_on_dyn_impl() {
     check_types(

crates/hir-ty/src/tests/regression.rs

@@ -1240,11 +1240,11 @@ fn test() {
             16..66 'for _ ...     }': IntoIterator::IntoIter<()>
             16..66 'for _ ...     }': &mut IntoIterator::IntoIter<()>
             16..66 'for _ ...     }': fn next<IntoIterator::IntoIter<()>>(&mut IntoIterator::IntoIter<()>) -> Option<<IntoIterator::IntoIter<()> as Iterator>::Item>
-            16..66 'for _ ...     }': Option<Iterator::Item<IntoIterator::IntoIter<()>>>
+            16..66 'for _ ...     }': Option<IntoIterator::Item<()>>
             16..66 'for _ ...     }': ()
             16..66 'for _ ...     }': ()
             16..66 'for _ ...     }': ()
-            20..21 '_': Iterator::Item<IntoIterator::IntoIter<()>>
+            20..21 '_': IntoIterator::Item<()>
             25..39 '{ let x = 0; }': ()
             31..32 'x': i32
             35..36 '0': i32

crates/hir-ty/src/tests/traits.rs

@@ -4148,6 +4148,30 @@ where
     );
 }
 
+#[test]
+fn gats_in_bounds_for_assoc() {
+    check_types(
+        r#"
+trait Trait {
+    type Assoc: Another<Gat<i32> = usize>;
+    type Assoc2<T>: Another<Gat<T> = T>;
+}
+trait Another {
+    type Gat<T>;
+    fn foo(&self) -> Self::Gat<i32>;
+    fn bar<T>(&self) -> Self::Gat<T>;
+}
+
+fn test<T: Trait>(a: T::Assoc, b: T::Assoc2<isize>) {
+    let v = a.foo();
+      //^ usize
+    let v = b.bar::<isize>();
+      //^ isize
+}
+"#,
+    );
+}
+
 #[test]
 fn bin_op_with_scalar_fallback() {
     // Extra impls are significant so that chalk doesn't give us definite guidances.

crates/hir-ty/src/traits.rs

@@ -170,7 +170,7 @@ fn solve(
 
 struct LoggingRustIrDatabaseLoggingOnDrop<'a>(LoggingRustIrDatabase<Interner, ChalkContext<'a>>);
 
-impl<'a> Drop for LoggingRustIrDatabaseLoggingOnDrop<'a> {
+impl Drop for LoggingRustIrDatabaseLoggingOnDrop<'_> {
     fn drop(&mut self) {
         eprintln!("chalk program:\n{}", self.0);
     }

crates/hir-ty/src/utils.rs

@@ -89,7 +89,7 @@ struct SuperTraits<'a> {
     seen: FxHashSet<ChalkTraitId>,
 }
 
-impl<'a> SuperTraits<'a> {
+impl SuperTraits<'_> {
     fn elaborate(&mut self, trait_ref: &TraitRef) {
         direct_super_trait_refs(self.db, trait_ref, |trait_ref| {
             if !self.seen.contains(&trait_ref.trait_id) {
@@ -99,7 +99,7 @@ impl<'a> SuperTraits<'a> {
     }
 }
 
-impl<'a> Iterator for SuperTraits<'a> {
+impl Iterator for SuperTraits<'_> {
     type Item = TraitRef;
 
     fn next(&mut self) -> Option<Self::Item> {

crates/hir/Cargo.toml

@@ -18,7 +18,7 @@ arrayvec = "0.7.2"
 itertools = "0.10.5"
 smallvec.workspace = true
 triomphe.workspace = true
-once_cell = "1.17.0"
+once_cell = "1.17.1"
 
 # local deps
 base-db.workspace = true