Auto merge of #3755 - rust-lang:rustup-2024-07-20, r=RalfJung

Automatic Rustup

.github/workflows/release.yaml

@@ -132,7 +132,7 @@ jobs:
         run: target/${{ matrix.target }}/release/rust-analyzer analysis-stats --with-deps $(rustc --print sysroot)/lib/rustlib/src/rust/library/std
 
       - name: Upload artifacts
-        uses: actions/upload-artifact@v1
+        uses: actions/upload-artifact@v4
         with:
           name: dist-${{ matrix.target }}
           path: ./dist
@@ -177,7 +177,7 @@ jobs:
       - run: rm -rf editors/code/server
 
       - name: Upload artifacts
-        uses: actions/upload-artifact@v1
+        uses: actions/upload-artifact@v4
         with:
           name: dist-x86_64-unknown-linux-musl
           path: ./dist
@@ -206,39 +206,39 @@ jobs:
       - run: echo "HEAD_SHA=$(git rev-parse HEAD)" >> $GITHUB_ENV
       - run: 'echo "HEAD_SHA: $HEAD_SHA"'
 
-      - uses: actions/download-artifact@v1
+      - uses: actions/download-artifact@v4
         with:
           name: dist-aarch64-apple-darwin
           path: dist
-      - uses: actions/download-artifact@v1
+      - uses: actions/download-artifact@v4
         with:
           name: dist-x86_64-apple-darwin
           path: dist
-      - uses: actions/download-artifact@v1
+      - uses: actions/download-artifact@v4
         with:
           name: dist-x86_64-unknown-linux-gnu
           path: dist
-      - uses: actions/download-artifact@v1
+      - uses: actions/download-artifact@v4
         with:
           name: dist-x86_64-unknown-linux-musl
           path: dist
-      - uses: actions/download-artifact@v1
+      - uses: actions/download-artifact@v4
         with:
           name: dist-aarch64-unknown-linux-gnu
           path: dist
-      - uses: actions/download-artifact@v1
+      - uses: actions/download-artifact@v4
         with:
           name: dist-arm-unknown-linux-gnueabihf
           path: dist
-      - uses: actions/download-artifact@v1
+      - uses: actions/download-artifact@v4
         with:
           name: dist-x86_64-pc-windows-msvc
           path: dist
-      - uses: actions/download-artifact@v1
+      - uses: actions/download-artifact@v4
         with:
           name: dist-i686-pc-windows-msvc
           path: dist
-      - uses: actions/download-artifact@v1
+      - uses: actions/download-artifact@v4
         with:
           name: dist-aarch64-pc-windows-msvc
           path: dist

Cargo.lock

@@ -167,9 +167,9 @@ checksum = "fd16c4719339c4530435d38e511904438d07cce7950afa3718a84ac36c10e89e"
 
 [[package]]
 name = "chalk-derive"
-version = "0.97.0"
+version = "0.98.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "92a0aedc4ac2adc5c0b7dc9ec38c5c816284ad28da6d4ecd01873b9683f54972"
+checksum = "9426c8fd0fe61c3da880b801d3b510524df17843a8f9ec1f5b9cec24fb7412df"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -179,9 +179,9 @@ dependencies = [
 
 [[package]]
 name = "chalk-ir"
-version = "0.97.0"
+version = "0.98.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "db18493569b190f7266a04901e520fc3a5c00564475154287906f8a27302c119"
+checksum = "d5f2eb1cd6054da221bd1ac0197fb2fe5e2caf3dcb93619398fc1433f8f09093"
 dependencies = [
  "bitflags 2.5.0",
  "chalk-derive",
@@ -189,9 +189,9 @@ dependencies = [
 
 [[package]]
 name = "chalk-recursive"
-version = "0.97.0"
+version = "0.98.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae4ba8ce5bd2e1b59f1f79495bc8704db09a8285e51cc5ddf01d9baee1bf447d"
+checksum = "129dc03458f71cfb9c3cd621c9c68166a94e87b85b16ccd29af015d7ff9a1c61"
 dependencies = [
  "chalk-derive",
  "chalk-ir",
@@ -202,9 +202,9 @@ dependencies = [
 
 [[package]]
 name = "chalk-solve"
-version = "0.97.0"
+version = "0.98.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b2ec1b3b7f7b1ec38f099ef39c2bc3ea29335be1b8316d114baff46d96d131e9"
+checksum = "d7e8a8c1e928f98cdf227b868416ef21dcd8cc3c61b347576d783713444d41c8"
 dependencies = [
  "chalk-derive",
  "chalk-ir",
@@ -221,11 +221,6 @@ name = "countme"
 version = "3.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7704b5fdd17b18ae31c4c1da5a2e0305a2bf17b5249300a9ee9ed7b72114c636"
-dependencies = [
- "dashmap",
- "once_cell",
- "rustc-hash",
-]
 
 [[package]]
 name = "cov-mark"
@@ -548,10 +543,10 @@ dependencies = [
  "limit",
  "mbe",
  "once_cell",
- "profile",
  "ra-ap-rustc_abi",
  "ra-ap-rustc_parse_format",
  "rustc-hash",
+ "rustc_apfloat",
  "smallvec",
  "span",
  "stdx",
@@ -616,9 +611,10 @@ dependencies = [
  "oorandom",
  "project-model",
  "ra-ap-rustc_abi",
- "ra-ap-rustc_index 0.53.0",
+ "ra-ap-rustc_index",
  "ra-ap-rustc_pattern_analysis",
  "rustc-hash",
+ "rustc_apfloat",
  "scoped-tls",
  "smallvec",
  "span",
@@ -664,6 +660,7 @@ dependencies = [
  "profile",
  "pulldown-cmark",
  "pulldown-cmark-to-cmark",
+ "rustc_apfloat",
  "smallvec",
  "span",
  "stdx",
@@ -809,7 +806,6 @@ checksum = "168fb715dda47215e360912c096649d23d58bf392ac62f73919e831745e40f26"
 dependencies = [
  "equivalent",
  "hashbrown",
- "serde",
 ]
 
 [[package]]
@@ -1046,6 +1042,7 @@ checksum = "75761162ae2b0e580d7e7c390558127e5f01b4194debd6221fd8c207fc80e3f5"
 name = "mbe"
 version = "0.0.0"
 dependencies = [
+ "arrayvec",
  "cov-mark",
  "parser",
  "rustc-hash",
@@ -1250,7 +1247,6 @@ dependencies = [
  "expect-test",
  "limit",
  "ra-ap-rustc_lexer",
- "sourcegen",
  "stdx",
  "tracing",
 ]
@@ -1328,18 +1324,14 @@ dependencies = [
  "base-db",
  "indexmap",
  "la-arena 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "memmap2",
- "object 0.33.0",
  "paths",
  "rustc-hash",
  "serde",
  "serde_json",
- "snap",
  "span",
  "stdx",
  "text-size",
  "tracing",
- "triomphe",
  "tt",
 ]
 
@@ -1357,6 +1349,7 @@ dependencies = [
  "proc-macro-api",
  "proc-macro-test",
  "ra-ap-rustc_lexer",
+ "snap",
  "span",
  "stdx",
  "tt",
@@ -1403,13 +1396,9 @@ name = "profile"
 version = "0.0.0"
 dependencies = [
  "cfg-if",
- "countme",
- "la-arena 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc",
- "once_cell",
  "perf-event",
  "tikv-jemalloc-ctl",
- "tracing",
  "windows-sys 0.52.0",
 ]
 
@@ -1492,21 +1481,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "80b1d613eee933486c0613a7bc26e515e46f43adf479d1edd5e537f983e9ce46"
 dependencies = [
  "bitflags 2.5.0",
- "ra-ap-rustc_index 0.53.0",
+ "ra-ap-rustc_index",
  "tracing",
 ]
 
-[[package]]
-name = "ra-ap-rustc_index"
-version = "0.44.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9ad68bacffb87dcdbb23a3ce11261375078aaa06b85d348c49f39ffd5510dc20"
-dependencies = [
- "arrayvec",
- "ra-ap-rustc_index_macros 0.44.0",
- "smallvec",
-]
-
 [[package]]
 name = "ra-ap-rustc_index"
 version = "0.53.0"
@@ -1514,22 +1492,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f072060ac77e9e1a02cc20028095993af7e72cc0804779c68bcbf47b16de49c9"
 dependencies = [
  "arrayvec",
- "ra-ap-rustc_index_macros 0.53.0",
+ "ra-ap-rustc_index_macros",
  "smallvec",
 ]
 
-[[package]]
-name = "ra-ap-rustc_index_macros"
-version = "0.44.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8782aaf3a113837c533dfb1c45df91cd17e1fdd1d2f9a20c2e0d1976025c4f1f"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
- "synstructure",
-]
-
 [[package]]
 name = "ra-ap-rustc_index_macros"
 version = "0.53.0"
@@ -1558,17 +1524,17 @@ version = "0.53.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "70dad7a491c2554590222e0c9212dcb7c2e7aceb668875075012a35ea780d135"
 dependencies = [
- "ra-ap-rustc_index 0.53.0",
+ "ra-ap-rustc_index",
  "ra-ap-rustc_lexer",
 ]
 
 [[package]]
 name = "ra-ap-rustc_pattern_analysis"
-version = "0.44.0"
+version = "0.53.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d63d1e1d5b2a13273cee1a10011147418f40e12b70f70578ce1dee0f1cafc334"
+checksum = "34768e1faf88c31f2e9ad57b48318a52b507dafac0cddbf01b5d63bfc0b0a365"
 dependencies = [
- "ra-ap-rustc_index 0.44.0",
+ "ra-ap-rustc_index",
  "rustc-hash",
  "rustc_apfloat",
  "smallvec",
@@ -1685,7 +1651,6 @@ dependencies = [
  "ide",
  "ide-db",
  "ide-ssr",
- "indexmap",
  "itertools",
  "load-cargo",
  "lsp-server 0.7.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1708,7 +1673,6 @@ dependencies = [
  "semver",
  "serde",
  "serde_json",
- "sourcegen",
  "stdx",
  "syntax",
  "test-fixture",
@@ -1907,13 +1871,6 @@ version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1b6b67fb9a61334225b5b790716f609cd58395f895b3fe8b328786812a40bc3b"
 
-[[package]]
-name = "sourcegen"
-version = "0.0.0"
-dependencies = [
- "xshell",
-]
-
 [[package]]
 name = "span"
 version = "0.0.0"
@@ -1985,6 +1942,7 @@ dependencies = [
  "rayon",
  "rowan",
  "rustc-hash",
+ "rustc_apfloat",
  "smol_str",
  "stdx",
  "test-utils",
@@ -2251,6 +2209,7 @@ dependencies = [
 name = "tt"
 version = "0.0.0"
 dependencies = [
+ "arrayvec",
  "smol_str",
  "stdx",
  "text-size",

Cargo.toml

@@ -10,9 +10,7 @@ license = "MIT OR Apache-2.0"
 authors = ["rust-analyzer team"]
 
 [profile.dev]
-# Disabling debug info speeds up builds a bunch,
+debug = 1
-# and we don't rely on it for debugging that much.
-debug = 0
 
 [profile.dev.package]
 # These speed up local tests.
@@ -89,10 +87,9 @@ ra-ap-rustc_lexer = { version = "0.53.0", default-features = false }
 ra-ap-rustc_parse_format = { version = "0.53.0", default-features = false }
 ra-ap-rustc_index = { version = "0.53.0", default-features = false }
 ra-ap-rustc_abi = { version = "0.53.0", default-features = false }
-ra-ap-rustc_pattern_analysis = { version = "0.44.0", default-features = false }
+ra-ap-rustc_pattern_analysis = { version = "0.53.0", default-features = false }
 
 # local crates that aren't published to crates.io. These should not have versions.
-sourcegen = { path = "./crates/sourcegen" }
 test-fixture = { path = "./crates/test-fixture" }
 test-utils = { path = "./crates/test-utils" }
 
@@ -107,10 +104,10 @@ arrayvec = "0.7.4"
 bitflags = "2.4.1"
 cargo_metadata = "0.18.1"
 camino = "1.1.6"
-chalk-solve = { version = "0.97.0", default-features = false }
+chalk-solve = { version = "0.98.0", default-features = false }
-chalk-ir = "0.97.0"
+chalk-ir = "0.98.0"
-chalk-recursive = { version = "0.97.0", default-features = false }
+chalk-recursive = { version = "0.98.0", default-features = false }
-chalk-derive = "0.97.0"
+chalk-derive = "0.98.0"
 crossbeam-channel = "0.5.8"
 dissimilar = "1.0.7"
 dot = "0.1.4"
@@ -122,6 +119,8 @@ hashbrown = { version = "0.14", features = [
 indexmap = "2.1.0"
 itertools = "0.12.0"
 libc = "0.2.150"
+libloading = "0.8.0"
+memmap2 = "0.5.4"
 nohash-hasher = "0.2.0"
 oorandom = "11.1.3"
 object = { version = "0.33.0", default-features = false, features = [
@@ -145,6 +144,7 @@ smallvec = { version = "1.10.0", features = [
   "const_generics",
 ] }
 smol_str = "0.2.1"
+snap = "1.1.0"
 text-size = "1.1.1"
 tracing = "0.1.40"
 tracing-tree = "0.3.0"
@@ -158,6 +158,7 @@ url = "2.3.1"
 xshell = "0.2.5"
 
 
+
 # We need to freeze the version of the crate, as the raw-api feature is considered unstable
 dashmap = { version = "=5.5.3", features = ["raw-api"] }
 

crates/base-db/src/lib.rs

@@ -1,7 +1,5 @@
 //! base_db defines basic database traits. The concrete DB is defined by ide.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 mod change;
 mod input;
 

crates/cfg/src/lib.rs

@@ -1,7 +1,5 @@
 //! cfg defines conditional compiling options, `cfg` attribute parser and evaluator
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 mod cfg_expr;
 mod dnf;
 #[cfg(test)]

crates/flycheck/src/lib.rs

@@ -6,8 +6,6 @@
 // addition to `cargo check`. Either split it into 3 crates (one for test, one for check
 // and one common utilities) or change its name and docs to reflect the current state.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 use std::{fmt, io, process::Command, time::Duration};
 
 use crossbeam_channel::{never, select, unbounded, Receiver, Sender};
@@ -428,6 +426,8 @@ impl FlycheckActor {
                     }
                 }
 
+                cmd.arg("--keep-going");
+
                 options.apply_on_command(&mut cmd);
                 (cmd, options.extra_args.clone())
             }

crates/hir-def/Cargo.toml

@@ -28,6 +28,7 @@ tracing.workspace = true
 smallvec.workspace = true
 hashbrown.workspace = true
 triomphe.workspace = true
+rustc_apfloat = "0.2.0"
 
 ra-ap-rustc_parse_format.workspace = true
 ra-ap-rustc_abi.workspace = true
@@ -37,7 +38,6 @@ stdx.workspace = true
 intern.workspace = true
 base-db.workspace = true
 syntax.workspace = true
-profile.workspace = true
 hir-expand.workspace = true
 mbe.workspace = true
 cfg.workspace = true

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

@@ -15,8 +15,8 @@ use span::AstIdMap;
 use stdx::never;
 use syntax::{
     ast::{
-        self, ArrayExprKind, AstChildren, BlockExpr, HasArgList, HasAttrs, HasLoopBody, HasName,
+        self, ArrayExprKind, AstChildren, BlockExpr, HasArgList, HasAttrs, HasGenericArgs,
-        RangeItem, SlicePatComponents,
+        HasLoopBody, HasName, RangeItem, SlicePatComponents,
     },
     AstNode, AstPtr, AstToken as _, SyntaxNodePtr,
 };

crates/hir-def/src/builtin_type.rs

@@ -30,8 +30,10 @@ pub enum BuiltinUint {
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub enum BuiltinFloat {
+    F16,
     F32,
     F64,
+    F128,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -65,8 +67,10 @@ impl BuiltinType {
         (name![u64],   BuiltinType::Uint(BuiltinUint::U64)),
         (name![u128],  BuiltinType::Uint(BuiltinUint::U128)),
 
+        (name![f16], BuiltinType::Float(BuiltinFloat::F16)),
         (name![f32], BuiltinType::Float(BuiltinFloat::F32)),
         (name![f64], BuiltinType::Float(BuiltinFloat::F64)),
+        (name![f128], BuiltinType::Float(BuiltinFloat::F128)),
     ];
 
     pub fn by_name(name: &Name) -> Option<Self> {
@@ -97,8 +101,10 @@ impl AsName for BuiltinType {
                 BuiltinUint::U128 => name![u128],
             },
             BuiltinType::Float(it) => match it {
+                BuiltinFloat::F16 => name![f16],
                 BuiltinFloat::F32 => name![f32],
                 BuiltinFloat::F64 => name![f64],
+                BuiltinFloat::F128 => name![f128],
             },
         }
     }
@@ -155,8 +161,10 @@ impl BuiltinUint {
 impl BuiltinFloat {
     pub fn from_suffix(suffix: &str) -> Option<BuiltinFloat> {
         let res = match suffix {
+            "f16" => BuiltinFloat::F16,
             "f32" => BuiltinFloat::F32,
             "f64" => BuiltinFloat::F64,
+            "f128" => BuiltinFloat::F128,
             _ => return None,
         };
         Some(res)
@@ -192,8 +200,10 @@ impl fmt::Display for BuiltinUint {
 impl fmt::Display for BuiltinFloat {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(match self {
+            BuiltinFloat::F16 => "f16",
             BuiltinFloat::F32 => "f32",
             BuiltinFloat::F64 => "f64",
+            BuiltinFloat::F128 => "f128",
         })
     }
 }

crates/hir-def/src/child_by_source.rs

@@ -214,8 +214,8 @@ impl ChildBySource for GenericDefId {
         }
 
         let generic_params = db.generic_params(*self);
-        let mut toc_idx_iter = generic_params.type_or_consts.iter().map(|(idx, _)| idx);
+        let mut toc_idx_iter = generic_params.iter_type_or_consts().map(|(idx, _)| idx);
-        let lts_idx_iter = generic_params.lifetimes.iter().map(|(idx, _)| idx);
+        let lts_idx_iter = generic_params.iter_lt().map(|(idx, _)| idx);
 
         // For traits the first type index is `Self`, skip it.
         if let GenericDefId::TraitId(_) = *self {

crates/hir-def/src/data.rs

@@ -323,7 +323,7 @@ impl TraitAliasData {
 pub struct ImplData {
     pub target_trait: Option<Interned<TraitRef>>,
     pub self_ty: Interned<TypeRef>,
-    pub items: Vec<AssocItemId>,
+    pub items: Box<[AssocItemId]>,
     pub is_negative: bool,
     pub is_unsafe: bool,
     // box it as the vec is usually empty anyways
@@ -637,10 +637,6 @@ impl<'a> AssocItemCollector<'a> {
                     attr,
                 ) {
                     Ok(ResolvedAttr::Macro(call_id)) => {
-                        // If proc attribute macro expansion is disabled, skip expanding it here
-                        if !self.db.expand_proc_attr_macros() {
-                            continue 'attrs;
-                        }
                         let loc = self.db.lookup_intern_macro_call(call_id);
                         if let MacroDefKind::ProcMacro(_, exp, _) = loc.def.kind {
                             // If there's no expander for the proc macro (e.g. the

crates/hir-def/src/db.rs

@@ -80,9 +80,11 @@ pub trait InternDatabase: SourceDatabase {
 
 #[salsa::query_group(DefDatabaseStorage)]
 pub trait DefDatabase: InternDatabase + ExpandDatabase + Upcast<dyn ExpandDatabase> {
+    /// Whether to expand procedural macros during name resolution.
     #[salsa::input]
     fn expand_proc_attr_macros(&self) -> bool;
 
+    /// Computes an [`ItemTree`] for the given file or macro expansion.
     #[salsa::invoke(ItemTree::file_item_tree_query)]
     fn file_item_tree(&self, file_id: HirFileId) -> Arc<ItemTree>;
 
@@ -96,6 +98,7 @@ pub trait DefDatabase: InternDatabase + ExpandDatabase + Upcast<dyn ExpandDataba
     #[salsa::invoke(DefMap::block_def_map_query)]
     fn block_def_map(&self, block: BlockId) -> Arc<DefMap>;
 
+    /// Turns a MacroId into a MacroDefId, describing the macro's definition post name resolution.
     fn macro_def(&self, m: MacroId) -> MacroDefId;
 
     // region:data
@@ -190,6 +193,7 @@ pub trait DefDatabase: InternDatabase + ExpandDatabase + Upcast<dyn ExpandDataba
     #[salsa::invoke(Attrs::fields_attrs_query)]
     fn fields_attrs(&self, def: VariantId) -> Arc<ArenaMap<LocalFieldId, Attrs>>;
 
+    // should this really be a query?
     #[salsa::invoke(crate::attr::fields_attrs_source_map)]
     fn fields_attrs_source_map(
         &self,

crates/hir-def/src/find_path.rs

@@ -183,6 +183,8 @@ fn find_path_for_module(
             let kind = if name_already_occupied_in_type_ns {
                 cov_mark::hit!(ambiguous_crate_start);
                 PathKind::Abs
+            } else if ctx.cfg.prefer_absolute {
+                PathKind::Abs
             } else {
                 PathKind::Plain
             };
@@ -564,7 +566,13 @@ mod tests {
     /// item the `path` refers to returns that same path when called from the
     /// module the cursor is in.
     #[track_caller]
-    fn check_found_path_(ra_fixture: &str, path: &str, prefer_prelude: bool, expect: Expect) {
+    fn check_found_path_(
+        ra_fixture: &str,
+        path: &str,
+        prefer_prelude: bool,
+        prefer_absolute: bool,
+        expect: Expect,
+    ) {
         let (db, pos) = TestDB::with_position(ra_fixture);
         let module = db.module_at_position(pos);
         let parsed_path_file =
@@ -604,7 +612,7 @@ mod tests {
                 module,
                 prefix,
                 ignore_local_imports,
-                ImportPathConfig { prefer_no_std: false, prefer_prelude },
+                ImportPathConfig { prefer_no_std: false, prefer_prelude, prefer_absolute },
             );
             format_to!(
                 res,
@@ -619,11 +627,15 @@ mod tests {
     }
 
     fn check_found_path(ra_fixture: &str, path: &str, expect: Expect) {
-        check_found_path_(ra_fixture, path, false, expect);
+        check_found_path_(ra_fixture, path, false, false, expect);
     }
 
     fn check_found_path_prelude(ra_fixture: &str, path: &str, expect: Expect) {
-        check_found_path_(ra_fixture, path, true, expect);
+        check_found_path_(ra_fixture, path, true, false, expect);
+    }
+
+    fn check_found_path_absolute(ra_fixture: &str, path: &str, expect: Expect) {
+        check_found_path_(ra_fixture, path, false, true, expect);
     }
 
     #[test]
@@ -870,6 +882,39 @@ pub mod ast {
         );
     }
 
+    #[test]
+    fn partially_imported_with_prefer_absolute() {
+        cov_mark::check!(partially_imported);
+        // Similar to partially_imported test case above, but with prefer_absolute enabled.
+        // Even if the actual imported item is in external crate, if the path to that item
+        // is starting from the imported name, then the path should not start from "::".
+        // i.e. The first line in the expected output should not start from "::".
+        check_found_path_absolute(
+            r#"
+//- /main.rs crate:main deps:syntax
+
+use syntax::ast;
+$0
+
+//- /lib.rs crate:syntax
+pub mod ast {
+    pub enum ModuleItem {
+        A, B, C,
+    }
+}
+        "#,
+            "syntax::ast::ModuleItem",
+            expect![[r#"
+                Plain  (imports ✔): ast::ModuleItem
+                Plain  (imports ✖): ::syntax::ast::ModuleItem
+                ByCrate(imports ✔): crate::ast::ModuleItem
+                ByCrate(imports ✖): ::syntax::ast::ModuleItem
+                BySelf (imports ✔): self::ast::ModuleItem
+                BySelf (imports ✖): ::syntax::ast::ModuleItem
+            "#]],
+        );
+    }
+
     #[test]
     fn same_crate_reexport() {
         check_found_path(
@@ -1769,6 +1814,43 @@ pub mod foo {
         );
     }
 
+    #[test]
+    fn respects_absolute_setting() {
+        let ra_fixture = r#"
+//- /main.rs crate:main deps:krate
+$0
+//- /krate.rs crate:krate
+pub mod foo {
+    pub struct Foo;
+}
+"#;
+        check_found_path(
+            ra_fixture,
+            "krate::foo::Foo",
+            expect![[r#"
+            Plain  (imports ✔): krate::foo::Foo
+            Plain  (imports ✖): krate::foo::Foo
+            ByCrate(imports ✔): krate::foo::Foo
+            ByCrate(imports ✖): krate::foo::Foo
+            BySelf (imports ✔): krate::foo::Foo
+            BySelf (imports ✖): krate::foo::Foo
+        "#]],
+        );
+
+        check_found_path_absolute(
+            ra_fixture,
+            "krate::foo::Foo",
+            expect![[r#"
+            Plain  (imports ✔): ::krate::foo::Foo
+            Plain  (imports ✖): ::krate::foo::Foo
+            ByCrate(imports ✔): ::krate::foo::Foo
+            ByCrate(imports ✖): ::krate::foo::Foo
+            BySelf (imports ✔): ::krate::foo::Foo
+            BySelf (imports ✖): ::krate::foo::Foo
+        "#]],
+        );
+    }
+
     #[test]
     fn respect_segment_length() {
         check_found_path(

crates/hir-def/src/generics.rs

@@ -28,6 +28,7 @@ use crate::{
     LocalLifetimeParamId, LocalTypeOrConstParamId, Lookup, TypeOrConstParamId, TypeParamId,
 };
 
+/// The index of the self param in the generic of the non-parent definition.
 const SELF_PARAM_ID_IN_SELF: la_arena::Idx<TypeOrConstParamData> =
     LocalTypeOrConstParamId::from_raw(RawIdx::from_u32(0));
 
@@ -158,9 +159,9 @@ pub enum GenericParamDataRef<'a> {
 /// Data about the generic parameters of a function, struct, impl, etc.
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub struct GenericParams {
-    pub type_or_consts: Arena<TypeOrConstParamData>,
+    type_or_consts: Arena<TypeOrConstParamData>,
-    pub lifetimes: Arena<LifetimeParamData>,
+    lifetimes: Arena<LifetimeParamData>,
-    pub where_predicates: Box<[WherePredicate]>,
+    where_predicates: Box<[WherePredicate]>,
 }
 
 impl ops::Index<LocalTypeOrConstParamId> for GenericParams {
@@ -205,6 +206,219 @@ pub enum WherePredicateTypeTarget {
     TypeOrConstParam(LocalTypeOrConstParamId),
 }
 
+impl GenericParams {
+    /// Number of Generic parameters (type_or_consts + lifetimes)
+    #[inline]
+    pub fn len(&self) -> usize {
+        self.type_or_consts.len() + self.lifetimes.len()
+    }
+
+    #[inline]
+    pub fn len_lifetimes(&self) -> usize {
+        self.lifetimes.len()
+    }
+
+    #[inline]
+    pub fn len_type_or_consts(&self) -> usize {
+        self.type_or_consts.len()
+    }
+
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
+    #[inline]
+    pub fn where_predicates(&self) -> std::slice::Iter<'_, WherePredicate> {
+        self.where_predicates.iter()
+    }
+
+    /// Iterator of type_or_consts field
+    #[inline]
+    pub fn iter_type_or_consts(
+        &self,
+    ) -> impl DoubleEndedIterator<Item = (LocalTypeOrConstParamId, &TypeOrConstParamData)> {
+        self.type_or_consts.iter()
+    }
+
+    /// Iterator of lifetimes field
+    #[inline]
+    pub fn iter_lt(
+        &self,
+    ) -> impl DoubleEndedIterator<Item = (LocalLifetimeParamId, &LifetimeParamData)> {
+        self.lifetimes.iter()
+    }
+
+    pub fn find_type_by_name(&self, name: &Name, parent: GenericDefId) -> Option<TypeParamId> {
+        self.type_or_consts.iter().find_map(|(id, p)| {
+            if p.name().as_ref() == Some(&name) && p.type_param().is_some() {
+                Some(TypeParamId::from_unchecked(TypeOrConstParamId { local_id: id, parent }))
+            } else {
+                None
+            }
+        })
+    }
+
+    pub fn find_const_by_name(&self, name: &Name, parent: GenericDefId) -> Option<ConstParamId> {
+        self.type_or_consts.iter().find_map(|(id, p)| {
+            if p.name().as_ref() == Some(&name) && p.const_param().is_some() {
+                Some(ConstParamId::from_unchecked(TypeOrConstParamId { local_id: id, parent }))
+            } else {
+                None
+            }
+        })
+    }
+
+    #[inline]
+    pub fn trait_self_param(&self) -> Option<LocalTypeOrConstParamId> {
+        if self.type_or_consts.is_empty() {
+            return None;
+        }
+        matches!(
+            self.type_or_consts[SELF_PARAM_ID_IN_SELF],
+            TypeOrConstParamData::TypeParamData(TypeParamData {
+                provenance: TypeParamProvenance::TraitSelf,
+                ..
+            })
+        )
+        .then(|| SELF_PARAM_ID_IN_SELF)
+    }
+
+    pub fn find_lifetime_by_name(
+        &self,
+        name: &Name,
+        parent: GenericDefId,
+    ) -> Option<LifetimeParamId> {
+        self.lifetimes.iter().find_map(|(id, p)| {
+            if &p.name == name {
+                Some(LifetimeParamId { local_id: id, parent })
+            } else {
+                None
+            }
+        })
+    }
+
+    pub(crate) fn generic_params_query(
+        db: &dyn DefDatabase,
+        def: GenericDefId,
+    ) -> Interned<GenericParams> {
+        let _p = tracing::info_span!("generic_params_query").entered();
+
+        let krate = def.krate(db);
+        let cfg_options = db.crate_graph();
+        let cfg_options = &cfg_options[krate].cfg_options;
+
+        // Returns the generic parameters that are enabled under the current `#[cfg]` options
+        let enabled_params =
+            |params: &Interned<GenericParams>, item_tree: &ItemTree, parent: GenericModItem| {
+                let enabled = |param| item_tree.attrs(db, krate, param).is_cfg_enabled(cfg_options);
+                let attr_owner_ct = |param| AttrOwner::TypeOrConstParamData(parent, param);
+                let attr_owner_lt = |param| AttrOwner::LifetimeParamData(parent, param);
+
+                // In the common case, no parameters will by disabled by `#[cfg]` attributes.
+                // Therefore, make a first pass to check if all parameters are enabled and, if so,
+                // clone the `Interned<GenericParams>` instead of recreating an identical copy.
+                let all_type_or_consts_enabled =
+                    params.type_or_consts.iter().all(|(idx, _)| enabled(attr_owner_ct(idx)));
+                let all_lifetimes_enabled =
+                    params.lifetimes.iter().all(|(idx, _)| enabled(attr_owner_lt(idx)));
+
+                if all_type_or_consts_enabled && all_lifetimes_enabled {
+                    params.clone()
+                } else {
+                    Interned::new(GenericParams {
+                        type_or_consts: all_type_or_consts_enabled
+                            .then(|| params.type_or_consts.clone())
+                            .unwrap_or_else(|| {
+                                params
+                                    .type_or_consts
+                                    .iter()
+                                    .filter(|&(idx, _)| enabled(attr_owner_ct(idx)))
+                                    .map(|(_, param)| param.clone())
+                                    .collect()
+                            }),
+                        lifetimes: all_lifetimes_enabled
+                            .then(|| params.lifetimes.clone())
+                            .unwrap_or_else(|| {
+                                params
+                                    .lifetimes
+                                    .iter()
+                                    .filter(|&(idx, _)| enabled(attr_owner_lt(idx)))
+                                    .map(|(_, param)| param.clone())
+                                    .collect()
+                            }),
+                        where_predicates: params.where_predicates.clone(),
+                    })
+                }
+            };
+        fn id_to_generics<Id: GenericsItemTreeNode>(
+            db: &dyn DefDatabase,
+            id: impl for<'db> Lookup<
+                Database<'db> = dyn DefDatabase + 'db,
+                Data = impl ItemTreeLoc<Id = Id>,
+            >,
+            enabled_params: impl Fn(
+                &Interned<GenericParams>,
+                &ItemTree,
+                GenericModItem,
+            ) -> Interned<GenericParams>,
+        ) -> Interned<GenericParams>
+        where
+            FileItemTreeId<Id>: Into<GenericModItem>,
+        {
+            let id = id.lookup(db).item_tree_id();
+            let tree = id.item_tree(db);
+            let item = &tree[id.value];
+            enabled_params(item.generic_params(), &tree, id.value.into())
+        }
+
+        match def {
+            GenericDefId::FunctionId(id) => {
+                let loc = id.lookup(db);
+                let tree = loc.id.item_tree(db);
+                let item = &tree[loc.id.value];
+
+                let enabled_params =
+                    enabled_params(&item.explicit_generic_params, &tree, loc.id.value.into());
+
+                let module = loc.container.module(db);
+                let func_data = db.function_data(id);
+                if func_data.params.is_empty() {
+                    enabled_params
+                } else {
+                    let mut generic_params = GenericParamsCollector {
+                        type_or_consts: enabled_params.type_or_consts.clone(),
+                        lifetimes: enabled_params.lifetimes.clone(),
+                        where_predicates: enabled_params.where_predicates.clone().into(),
+                    };
+
+                    // Don't create an `Expander` if not needed since this
+                    // could cause a reparse after the `ItemTree` has been created due to the spanmap.
+                    let mut expander = Lazy::new(|| {
+                        (module.def_map(db), Expander::new(db, loc.id.file_id(), module))
+                    });
+                    for param in func_data.params.iter() {
+                        generic_params.fill_implicit_impl_trait_args(db, &mut expander, param);
+                    }
+                    Interned::new(generic_params.finish())
+                }
+            }
+            GenericDefId::AdtId(AdtId::StructId(id)) => id_to_generics(db, id, enabled_params),
+            GenericDefId::AdtId(AdtId::EnumId(id)) => id_to_generics(db, id, enabled_params),
+            GenericDefId::AdtId(AdtId::UnionId(id)) => id_to_generics(db, id, enabled_params),
+            GenericDefId::TraitId(id) => id_to_generics(db, id, enabled_params),
+            GenericDefId::TraitAliasId(id) => id_to_generics(db, id, enabled_params),
+            GenericDefId::TypeAliasId(id) => id_to_generics(db, id, enabled_params),
+            GenericDefId::ImplId(id) => id_to_generics(db, id, enabled_params),
+            GenericDefId::ConstId(_) => Interned::new(GenericParams {
+                type_or_consts: Default::default(),
+                lifetimes: Default::default(),
+                where_predicates: Default::default(),
+            }),
+        }
+    }
+}
+
 #[derive(Clone, Default)]
 pub(crate) struct GenericParamsCollector {
     pub(crate) type_or_consts: Arena<TypeOrConstParamData>,
@@ -441,202 +655,3 @@ impl GenericParamsCollector {
         }
     }
 }
-
-impl GenericParams {
-    /// Number of Generic parameters (type_or_consts + lifetimes)
-    #[inline]
-    pub fn len(&self) -> usize {
-        self.type_or_consts.len() + self.lifetimes.len()
-    }
-
-    #[inline]
-    pub fn is_empty(&self) -> bool {
-        self.len() == 0
-    }
-
-    /// Iterator of type_or_consts field
-    #[inline]
-    pub fn iter_type_or_consts(
-        &self,
-    ) -> impl DoubleEndedIterator<Item = (LocalTypeOrConstParamId, &TypeOrConstParamData)> {
-        self.type_or_consts.iter()
-    }
-
-    /// Iterator of lifetimes field
-    #[inline]
-    pub fn iter_lt(
-        &self,
-    ) -> impl DoubleEndedIterator<Item = (LocalLifetimeParamId, &LifetimeParamData)> {
-        self.lifetimes.iter()
-    }
-
-    pub(crate) fn generic_params_query(
-        db: &dyn DefDatabase,
-        def: GenericDefId,
-    ) -> Interned<GenericParams> {
-        let _p = tracing::info_span!("generic_params_query").entered();
-
-        let krate = def.module(db).krate;
-        let cfg_options = db.crate_graph();
-        let cfg_options = &cfg_options[krate].cfg_options;
-
-        // Returns the generic parameters that are enabled under the current `#[cfg]` options
-        let enabled_params =
-            |params: &Interned<GenericParams>, item_tree: &ItemTree, parent: GenericModItem| {
-                let enabled = |param| item_tree.attrs(db, krate, param).is_cfg_enabled(cfg_options);
-                let attr_owner_ct = |param| AttrOwner::TypeOrConstParamData(parent, param);
-                let attr_owner_lt = |param| AttrOwner::LifetimeParamData(parent, param);
-
-                // In the common case, no parameters will by disabled by `#[cfg]` attributes.
-                // Therefore, make a first pass to check if all parameters are enabled and, if so,
-                // clone the `Interned<GenericParams>` instead of recreating an identical copy.
-                let all_type_or_consts_enabled =
-                    params.type_or_consts.iter().all(|(idx, _)| enabled(attr_owner_ct(idx)));
-                let all_lifetimes_enabled =
-                    params.lifetimes.iter().all(|(idx, _)| enabled(attr_owner_lt(idx)));
-
-                if all_type_or_consts_enabled && all_lifetimes_enabled {
-                    params.clone()
-                } else {
-                    Interned::new(GenericParams {
-                        type_or_consts: all_type_or_consts_enabled
-                            .then(|| params.type_or_consts.clone())
-                            .unwrap_or_else(|| {
-                                params
-                                    .type_or_consts
-                                    .iter()
-                                    .filter(|&(idx, _)| enabled(attr_owner_ct(idx)))
-                                    .map(|(_, param)| param.clone())
-                                    .collect()
-                            }),
-                        lifetimes: all_lifetimes_enabled
-                            .then(|| params.lifetimes.clone())
-                            .unwrap_or_else(|| {
-                                params
-                                    .lifetimes
-                                    .iter()
-                                    .filter(|&(idx, _)| enabled(attr_owner_lt(idx)))
-                                    .map(|(_, param)| param.clone())
-                                    .collect()
-                            }),
-                        where_predicates: params.where_predicates.clone(),
-                    })
-                }
-            };
-        fn id_to_generics<Id: GenericsItemTreeNode>(
-            db: &dyn DefDatabase,
-            id: impl for<'db> Lookup<
-                Database<'db> = dyn DefDatabase + 'db,
-                Data = impl ItemTreeLoc<Id = Id>,
-            >,
-            enabled_params: impl Fn(
-                &Interned<GenericParams>,
-                &ItemTree,
-                GenericModItem,
-            ) -> Interned<GenericParams>,
-        ) -> Interned<GenericParams>
-        where
-            FileItemTreeId<Id>: Into<GenericModItem>,
-        {
-            let id = id.lookup(db).item_tree_id();
-            let tree = id.item_tree(db);
-            let item = &tree[id.value];
-            enabled_params(item.generic_params(), &tree, id.value.into())
-        }
-
-        match def {
-            GenericDefId::FunctionId(id) => {
-                let loc = id.lookup(db);
-                let tree = loc.id.item_tree(db);
-                let item = &tree[loc.id.value];
-
-                let enabled_params =
-                    enabled_params(&item.explicit_generic_params, &tree, loc.id.value.into());
-
-                let module = loc.container.module(db);
-                let func_data = db.function_data(id);
-                if func_data.params.is_empty() {
-                    enabled_params
-                } else {
-                    let mut generic_params = GenericParamsCollector {
-                        type_or_consts: enabled_params.type_or_consts.clone(),
-                        lifetimes: enabled_params.lifetimes.clone(),
-                        where_predicates: enabled_params.where_predicates.clone().into(),
-                    };
-
-                    // Don't create an `Expander` if not needed since this
-                    // could cause a reparse after the `ItemTree` has been created due to the spanmap.
-                    let mut expander = Lazy::new(|| {
-                        (module.def_map(db), Expander::new(db, loc.id.file_id(), module))
-                    });
-                    for param in func_data.params.iter() {
-                        generic_params.fill_implicit_impl_trait_args(db, &mut expander, param);
-                    }
-                    Interned::new(generic_params.finish())
-                }
-            }
-            GenericDefId::AdtId(AdtId::StructId(id)) => id_to_generics(db, id, enabled_params),
-            GenericDefId::AdtId(AdtId::EnumId(id)) => id_to_generics(db, id, enabled_params),
-            GenericDefId::AdtId(AdtId::UnionId(id)) => id_to_generics(db, id, enabled_params),
-            GenericDefId::TraitId(id) => id_to_generics(db, id, enabled_params),
-            GenericDefId::TraitAliasId(id) => id_to_generics(db, id, enabled_params),
-            GenericDefId::TypeAliasId(id) => id_to_generics(db, id, enabled_params),
-            GenericDefId::ImplId(id) => id_to_generics(db, id, enabled_params),
-            GenericDefId::EnumVariantId(_) | GenericDefId::ConstId(_) => {
-                Interned::new(GenericParams {
-                    type_or_consts: Default::default(),
-                    lifetimes: Default::default(),
-                    where_predicates: Default::default(),
-                })
-            }
-        }
-    }
-
-    pub fn find_type_by_name(&self, name: &Name, parent: GenericDefId) -> Option<TypeParamId> {
-        self.type_or_consts.iter().find_map(|(id, p)| {
-            if p.name().as_ref() == Some(&name) && p.type_param().is_some() {
-                Some(TypeParamId::from_unchecked(TypeOrConstParamId { local_id: id, parent }))
-            } else {
-                None
-            }
-        })
-    }
-
-    pub fn find_const_by_name(&self, name: &Name, parent: GenericDefId) -> Option<ConstParamId> {
-        self.type_or_consts.iter().find_map(|(id, p)| {
-            if p.name().as_ref() == Some(&name) && p.const_param().is_some() {
-                Some(ConstParamId::from_unchecked(TypeOrConstParamId { local_id: id, parent }))
-            } else {
-                None
-            }
-        })
-    }
-
-    pub fn trait_self_param(&self) -> Option<LocalTypeOrConstParamId> {
-        if self.type_or_consts.is_empty() {
-            return None;
-        }
-        matches!(
-            self.type_or_consts[SELF_PARAM_ID_IN_SELF],
-            TypeOrConstParamData::TypeParamData(TypeParamData {
-                provenance: TypeParamProvenance::TraitSelf,
-                ..
-            })
-        )
-        .then(|| SELF_PARAM_ID_IN_SELF)
-    }
-
-    pub fn find_lifetime_by_name(
-        &self,
-        name: &Name,
-        parent: GenericDefId,
-    ) -> Option<LifetimeParamId> {
-        self.lifetimes.iter().find_map(|(id, p)| {
-            if &p.name == name {
-                Some(LifetimeParamId { local_id: id, parent })
-            } else {
-                None
-            }
-        })
-    }
-}

crates/hir-def/src/hir.rs

@@ -20,6 +20,7 @@ use std::fmt;
 use hir_expand::name::Name;
 use intern::Interned;
 use la_arena::{Idx, RawIdx};
+use rustc_apfloat::ieee::{Half as f16, Quad as f128};
 use smallvec::SmallVec;
 use syntax::ast;
 
@@ -56,29 +57,38 @@ pub struct Label {
 }
 pub type LabelId = Idx<Label>;
 
-// We convert float values into bits and that's how we don't need to deal with f32 and f64.
+// We leave float values as a string to avoid double rounding.
-// For PartialEq, bits comparison should work, as ordering is not important
+// For PartialEq, string comparison should work, as ordering is not important
 // https://github.com/rust-lang/rust-analyzer/issues/12380#issuecomment-1137284360
-#[derive(Default, Debug, Clone, Copy, Eq, PartialEq)]
+#[derive(Default, Debug, Clone, Eq, PartialEq)]
-pub struct FloatTypeWrapper(u64);
+pub struct FloatTypeWrapper(Box<str>);
 
+// FIXME(#17451): Use builtin types once stabilised.
 impl FloatTypeWrapper {
-    pub fn new(value: f64) -> Self {
+    pub fn new(value: String) -> Self {
-        Self(value.to_bits())
+        Self(value.into())
     }
 
-    pub fn into_f64(self) -> f64 {
+    pub fn to_f128(&self) -> f128 {
-        f64::from_bits(self.0)
+        self.0.parse().unwrap_or_default()
     }
 
-    pub fn into_f32(self) -> f32 {
+    pub fn to_f64(&self) -> f64 {
-        f64::from_bits(self.0) as f32
+        self.0.parse().unwrap_or_default()
+    }
+
+    pub fn to_f32(&self) -> f32 {
+        self.0.parse().unwrap_or_default()
+    }
+
+    pub fn to_f16(&self) -> f16 {
+        self.0.parse().unwrap_or_default()
     }
 }
 
 impl fmt::Display for FloatTypeWrapper {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{:?}", f64::from_bits(self.0))
+        f.write_str(&self.0)
     }
 }
 
@@ -91,7 +101,7 @@ pub enum Literal {
     Bool(bool),
     Int(i128, Option<BuiltinInt>),
     Uint(u128, Option<BuiltinUint>),
-    // Here we are using a wrapper around float because f32 and f64 do not implement Eq, so they
+    // Here we are using a wrapper around float because float primitives do not implement Eq, so they
     // could not be used directly here, to understand how the wrapper works go to definition of
     // FloatTypeWrapper
     Float(FloatTypeWrapper, Option<BuiltinFloat>),
@@ -120,10 +130,7 @@ impl From<ast::LiteralKind> for Literal {
         match ast_lit_kind {
             LiteralKind::IntNumber(lit) => {
                 if let builtin @ Some(_) = lit.suffix().and_then(BuiltinFloat::from_suffix) {
-                    Literal::Float(
+                    Literal::Float(FloatTypeWrapper::new(lit.value_string()), builtin)
-                        FloatTypeWrapper::new(lit.float_value().unwrap_or(Default::default())),
-                        builtin,
-                    )
                 } else if let builtin @ Some(_) = lit.suffix().and_then(BuiltinUint::from_suffix) {
                     Literal::Uint(lit.value().unwrap_or(0), builtin)
                 } else {
@@ -133,7 +140,7 @@ impl From<ast::LiteralKind> for Literal {
             }
             LiteralKind::FloatNumber(lit) => {
                 let ty = lit.suffix().and_then(BuiltinFloat::from_suffix);
-                Literal::Float(FloatTypeWrapper::new(lit.value().unwrap_or(Default::default())), ty)
+                Literal::Float(FloatTypeWrapper::new(lit.value_string()), ty)
             }
             LiteralKind::ByteString(bs) => {
                 let text = bs.value().map_or_else(|_| Default::default(), Box::from);

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

@@ -10,7 +10,7 @@ use hir_expand::{
     AstId,
 };
 use intern::Interned;
-use syntax::ast::{self, HasName, IsString};
+use syntax::ast::{self, HasGenericArgs, HasName, IsString};
 
 use crate::{
     builtin_type::{BuiltinInt, BuiltinType, BuiltinUint},
@@ -245,7 +245,13 @@ impl TypeRef {
             // for types are close enough for our purposes to the inner type for now...
             ast::Type::ForType(inner) => TypeRef::from_ast_opt(ctx, inner.ty()),
             ast::Type::ImplTraitType(inner) => {
-                TypeRef::ImplTrait(type_bounds_from_ast(ctx, inner.type_bound_list()))
+                if ctx.outer_impl_trait() {
+                    // Disallow nested impl traits
+                    TypeRef::Error
+                } else {
+                    let _guard = ctx.outer_impl_trait_scope(true);
+                    TypeRef::ImplTrait(type_bounds_from_ast(ctx, inner.type_bound_list()))
+                }
             }
             ast::Type::DynTraitType(inner) => {
                 TypeRef::DynTrait(type_bounds_from_ast(ctx, inner.type_bound_list()))

crates/hir-def/src/item_scope.rs

@@ -8,7 +8,6 @@ use hir_expand::{attrs::AttrId, db::ExpandDatabase, name::Name, AstId, MacroCall
 use itertools::Itertools;
 use la_arena::Idx;
 use once_cell::sync::Lazy;
-use profile::Count;
 use rustc_hash::{FxHashMap, FxHashSet};
 use smallvec::{smallvec, SmallVec};
 use stdx::format_to;
@@ -65,8 +64,6 @@ pub struct ImportId {
 
 #[derive(Debug, Default, PartialEq, Eq)]
 pub struct ItemScope {
-    _c: Count<Self>,
-
     /// Defs visible in this scope. This includes `declarations`, but also
     /// imports. The imports belong to this module and can be resolved by using them on
     /// the `use_imports_*` fields.
@@ -722,7 +719,6 @@ impl ItemScope {
     pub(crate) fn shrink_to_fit(&mut self) {
         // Exhaustive match to require handling new fields.
         let Self {
-            _c: _,
             types,
             values,
             macros,

crates/hir-def/src/item_tree.rs

@@ -48,6 +48,7 @@ use either::Either;
 use hir_expand::{attrs::RawAttrs, name::Name, ExpandTo, HirFileId, InFile};
 use intern::Interned;
 use la_arena::{Arena, Idx, IdxRange, RawIdx};
+use once_cell::sync::OnceCell;
 use rustc_hash::FxHashMap;
 use smallvec::SmallVec;
 use span::{AstIdNode, FileAstId, SyntaxContextId};
@@ -100,6 +101,7 @@ pub struct ItemTree {
 impl ItemTree {
     pub(crate) fn file_item_tree_query(db: &dyn DefDatabase, file_id: HirFileId) -> Arc<ItemTree> {
         let _p = tracing::info_span!("file_item_tree_query", ?file_id).entered();
+        static EMPTY: OnceCell<Arc<ItemTree>> = OnceCell::new();
 
         let syntax = db.parse_or_expand(file_id);
 
@@ -131,18 +133,47 @@ impl ItemTree {
         if let Some(attrs) = top_attrs {
             item_tree.attrs.insert(AttrOwner::TopLevel, attrs);
         }
-        item_tree.shrink_to_fit();
+        if item_tree.data.is_none() && item_tree.top_level.is_empty() && item_tree.attrs.is_empty()
-        Arc::new(item_tree)
+        {
+            EMPTY
+                .get_or_init(|| {
+                    Arc::new(ItemTree {
+                        top_level: SmallVec::new_const(),
+                        attrs: FxHashMap::default(),
+                        data: None,
+                    })
+                })
+                .clone()
+        } else {
+            item_tree.shrink_to_fit();
+            Arc::new(item_tree)
+        }
     }
 
     pub(crate) fn block_item_tree_query(db: &dyn DefDatabase, block: BlockId) -> Arc<ItemTree> {
+        let _p = tracing::info_span!("block_item_tree_query", ?block).entered();
+        static EMPTY: OnceCell<Arc<ItemTree>> = OnceCell::new();
+
         let loc = block.lookup(db);
         let block = loc.ast_id.to_node(db.upcast());
 
         let ctx = lower::Ctx::new(db, loc.ast_id.file_id);
         let mut item_tree = ctx.lower_block(&block);
-        item_tree.shrink_to_fit();
+        if item_tree.data.is_none() && item_tree.top_level.is_empty() && item_tree.attrs.is_empty()
-        Arc::new(item_tree)
+        {
+            EMPTY
+                .get_or_init(|| {
+                    Arc::new(ItemTree {
+                        top_level: SmallVec::new_const(),
+                        attrs: FxHashMap::default(),
+                        data: None,
+                    })
+                })
+                .clone()
+        } else {
+            item_tree.shrink_to_fit();
+            Arc::new(item_tree)
+        }
     }
 
     /// Returns an iterator over all items located at the top level of the `HirFileId` this
@@ -585,24 +616,30 @@ impl Index<RawVisibilityId> for ItemTree {
     type Output = RawVisibility;
     fn index(&self, index: RawVisibilityId) -> &Self::Output {
         static VIS_PUB: RawVisibility = RawVisibility::Public;
-        static VIS_PRIV_IMPLICIT: RawVisibility = RawVisibility::Module(
+        static VIS_PRIV_IMPLICIT: OnceCell<RawVisibility> = OnceCell::new();
-            ModPath::from_kind(PathKind::SELF),
+        static VIS_PRIV_EXPLICIT: OnceCell<RawVisibility> = OnceCell::new();
-            VisibilityExplicitness::Implicit,
+        static VIS_PUB_CRATE: OnceCell<RawVisibility> = OnceCell::new();
-        );
-        static VIS_PRIV_EXPLICIT: RawVisibility = RawVisibility::Module(
-            ModPath::from_kind(PathKind::SELF),
-            VisibilityExplicitness::Explicit,
-        );
-        static VIS_PUB_CRATE: RawVisibility = RawVisibility::Module(
-            ModPath::from_kind(PathKind::Crate),
-            VisibilityExplicitness::Explicit,
-        );
 
         match index {
-            RawVisibilityId::PRIV_IMPLICIT => &VIS_PRIV_IMPLICIT,
+            RawVisibilityId::PRIV_IMPLICIT => VIS_PRIV_IMPLICIT.get_or_init(|| {
-            RawVisibilityId::PRIV_EXPLICIT => &VIS_PRIV_EXPLICIT,
+                RawVisibility::Module(
+                    Interned::new(ModPath::from_kind(PathKind::SELF)),
+                    VisibilityExplicitness::Implicit,
+                )
+            }),
+            RawVisibilityId::PRIV_EXPLICIT => VIS_PRIV_EXPLICIT.get_or_init(|| {
+                RawVisibility::Module(
+                    Interned::new(ModPath::from_kind(PathKind::SELF)),
+                    VisibilityExplicitness::Explicit,
+                )
+            }),
             RawVisibilityId::PUB => &VIS_PUB,
-            RawVisibilityId::PUB_CRATE => &VIS_PUB_CRATE,
+            RawVisibilityId::PUB_CRATE => VIS_PUB_CRATE.get_or_init(|| {
+                RawVisibility::Module(
+                    Interned::new(ModPath::from_kind(PathKind::Crate)),
+                    VisibilityExplicitness::Explicit,
+                )
+            }),
             _ => &self.data().vis.arena[Idx::from_raw(index.0.into())],
         }
     }

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

@@ -532,7 +532,7 @@ impl Printer<'_> {
 
         w!(self, "<");
         let mut first = true;
-        for (idx, lt) in params.lifetimes.iter() {
+        for (idx, lt) in params.iter_lt() {
             if !first {
                 w!(self, ", ");
             }
@@ -540,7 +540,7 @@ impl Printer<'_> {
             self.print_attrs_of(AttrOwner::LifetimeParamData(parent, idx), " ");
             w!(self, "{}", lt.name.display(self.db.upcast()));
         }
-        for (idx, x) in params.type_or_consts.iter() {
+        for (idx, x) in params.iter_type_or_consts() {
             if !first {
                 w!(self, ", ");
             }
@@ -570,13 +570,13 @@ impl Printer<'_> {
     }
 
     fn print_where_clause(&mut self, params: &GenericParams) -> bool {
-        if params.where_predicates.is_empty() {
+        if params.where_predicates().next().is_none() {
             return false;
         }
 
         w!(self, "\nwhere");
         self.indented(|this| {
-            for (i, pred) in params.where_predicates.iter().enumerate() {
+            for (i, pred) in params.where_predicates().enumerate() {
                 if i != 0 {
                     wln!(this, ",");
                 }
@@ -607,12 +607,10 @@ impl Printer<'_> {
 
                 match target {
                     WherePredicateTypeTarget::TypeRef(ty) => this.print_type_ref(ty),
-                    WherePredicateTypeTarget::TypeOrConstParam(id) => {
+                    WherePredicateTypeTarget::TypeOrConstParam(id) => match params[*id].name() {
-                        match &params.type_or_consts[*id].name() {
+                        Some(name) => w!(this, "{}", name.display(self.db.upcast())),
-                            Some(name) => w!(this, "{}", name.display(self.db.upcast())),
+                        None => w!(this, "_anon_{}", id.into_raw()),
-                            None => w!(this, "_anon_{}", id.into_raw()),
+                    },
-                        }
-                    }
                 }
                 w!(this, ": ");
                 this.print_type_bounds(std::slice::from_ref(bound));

crates/hir-def/src/lib.rs

@@ -7,7 +7,6 @@
 //! Note that `hir_def` is a work in progress, so not all of the above is
 //! actually true.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 
 #[cfg(feature = "in-rust-tree")]
@@ -117,6 +116,8 @@ pub struct ImportPathConfig {
     pub prefer_no_std: bool,
     /// If true, prefer import paths containing a prelude module.
     pub prefer_prelude: bool,
+    /// If true, prefer abs path (starting with `::`) where it is available.
+    pub prefer_absolute: bool,
 }
 
 #[derive(Debug)]
@@ -689,7 +690,7 @@ pub enum TypeOwnerId {
 }
 
 impl TypeOwnerId {
-    fn as_generic_def_id(self) -> Option<GenericDefId> {
+    fn as_generic_def_id(self, db: &dyn DefDatabase) -> Option<GenericDefId> {
         Some(match self {
             TypeOwnerId::FunctionId(it) => GenericDefId::FunctionId(it),
             TypeOwnerId::ConstId(it) => GenericDefId::ConstId(it),
@@ -698,7 +699,9 @@ impl TypeOwnerId {
             TypeOwnerId::TraitAliasId(it) => GenericDefId::TraitAliasId(it),
             TypeOwnerId::TypeAliasId(it) => GenericDefId::TypeAliasId(it),
             TypeOwnerId::ImplId(it) => GenericDefId::ImplId(it),
-            TypeOwnerId::EnumVariantId(it) => GenericDefId::EnumVariantId(it),
+            TypeOwnerId::EnumVariantId(it) => {
+                GenericDefId::AdtId(AdtId::EnumId(it.lookup(db).parent))
+            }
             TypeOwnerId::InTypeConstId(_) | TypeOwnerId::StaticId(_) => return None,
         })
     }
@@ -740,7 +743,6 @@ impl From<GenericDefId> for TypeOwnerId {
             GenericDefId::TraitAliasId(it) => it.into(),
             GenericDefId::TypeAliasId(it) => it.into(),
             GenericDefId::ImplId(it) => it.into(),
-            GenericDefId::EnumVariantId(it) => it.into(),
             GenericDefId::ConstId(it) => it.into(),
         }
     }
@@ -849,8 +851,8 @@ impl GeneralConstId {
     pub fn generic_def(self, db: &dyn DefDatabase) -> Option<GenericDefId> {
         match self {
             GeneralConstId::ConstId(it) => Some(it.into()),
-            GeneralConstId::ConstBlockId(it) => it.lookup(db).parent.as_generic_def_id(),
+            GeneralConstId::ConstBlockId(it) => it.lookup(db).parent.as_generic_def_id(db),
-            GeneralConstId::InTypeConstId(it) => it.lookup(db).owner.as_generic_def_id(),
+            GeneralConstId::InTypeConstId(it) => it.lookup(db).owner.as_generic_def_id(db),
         }
     }
 
@@ -888,12 +890,12 @@ impl From<EnumVariantId> for DefWithBodyId {
 }
 
 impl DefWithBodyId {
-    pub fn as_generic_def_id(self) -> Option<GenericDefId> {
+    pub fn as_generic_def_id(self, db: &dyn DefDatabase) -> Option<GenericDefId> {
         match self {
             DefWithBodyId::FunctionId(f) => Some(f.into()),
             DefWithBodyId::StaticId(_) => None,
             DefWithBodyId::ConstId(c) => Some(c.into()),
-            DefWithBodyId::VariantId(c) => Some(c.into()),
+            DefWithBodyId::VariantId(c) => Some(c.lookup(db).parent.into()),
             // FIXME: stable rust doesn't allow generics in constants, but we should
             // use `TypeOwnerId::as_generic_def_id` when it does.
             DefWithBodyId::InTypeConstId(_) => None,
@@ -921,10 +923,6 @@ pub enum GenericDefId {
     TraitAliasId(TraitAliasId),
     TypeAliasId(TypeAliasId),
     ImplId(ImplId),
-    // enum variants cannot have generics themselves, but their parent enums
-    // can, and this makes some code easier to write
-    // FIXME: Try to remove this as that will reduce the amount of query slots generated per enum?
-    EnumVariantId(EnumVariantId),
     // consts can have type parameters from their parents (i.e. associated consts of traits)
     ConstId(ConstId),
 }
@@ -935,7 +933,6 @@ impl_from!(
     TraitAliasId,
     TypeAliasId,
     ImplId,
-    EnumVariantId,
     ConstId
     for GenericDefId
 );
@@ -967,7 +964,6 @@ impl GenericDefId {
             GenericDefId::TraitAliasId(it) => file_id_and_params_of_item_loc(db, it),
             GenericDefId::ImplId(it) => file_id_and_params_of_item_loc(db, it),
             GenericDefId::ConstId(it) => (it.lookup(db).id.file_id(), None),
-            GenericDefId::EnumVariantId(it) => (it.lookup(db).id.file_id(), None),
         }
     }
 
@@ -982,6 +978,14 @@ impl GenericDefId {
             _ => None,
         }
     }
+
+    pub fn from_callable(db: &dyn DefDatabase, def: CallableDefId) -> GenericDefId {
+        match def {
+            CallableDefId::FunctionId(f) => f.into(),
+            CallableDefId::StructId(s) => s.into(),
+            CallableDefId::EnumVariantId(e) => e.lookup(db).parent.into(),
+        }
+    }
 }
 
 impl From<AssocItemId> for GenericDefId {
@@ -994,6 +998,36 @@ impl From<AssocItemId> for GenericDefId {
     }
 }
 
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum CallableDefId {
+    FunctionId(FunctionId),
+    StructId(StructId),
+    EnumVariantId(EnumVariantId),
+}
+
+impl InternValueTrivial for CallableDefId {}
+
+impl_from!(FunctionId, StructId, EnumVariantId for CallableDefId);
+impl From<CallableDefId> for ModuleDefId {
+    fn from(def: CallableDefId) -> ModuleDefId {
+        match def {
+            CallableDefId::FunctionId(f) => ModuleDefId::FunctionId(f),
+            CallableDefId::StructId(s) => ModuleDefId::AdtId(AdtId::StructId(s)),
+            CallableDefId::EnumVariantId(e) => ModuleDefId::EnumVariantId(e),
+        }
+    }
+}
+
+impl CallableDefId {
+    pub fn krate(self, db: &dyn DefDatabase) -> CrateId {
+        match self {
+            CallableDefId::FunctionId(f) => f.krate(db),
+            CallableDefId::StructId(s) => s.krate(db),
+            CallableDefId::EnumVariantId(e) => e.krate(db),
+        }
+    }
+}
+
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub enum AttrDefId {
     ModuleId(ModuleId),
@@ -1310,7 +1344,6 @@ impl HasModule for GenericDefId {
             GenericDefId::TraitAliasId(it) => it.module(db),
             GenericDefId::TypeAliasId(it) => it.module(db),
             GenericDefId::ImplId(it) => it.module(db),
-            GenericDefId::EnumVariantId(it) => it.module(db),
             GenericDefId::ConstId(it) => it.module(db),
         }
     }

crates/hir-def/src/lower.rs

@@ -18,6 +18,26 @@ pub struct LowerCtx<'a> {
     span_map: OnceCell<SpanMap>,
     ast_id_map: OnceCell<Arc<AstIdMap>>,
     impl_trait_bounds: RefCell<Vec<Vec<Interned<TypeBound>>>>,
+    // Prevent nested impl traits like `impl Foo<impl Bar>`.
+    outer_impl_trait: RefCell<bool>,
+}
+
+pub(crate) struct OuterImplTraitGuard<'a> {
+    ctx: &'a LowerCtx<'a>,
+    old: bool,
+}
+
+impl<'a> OuterImplTraitGuard<'a> {
+    fn new(ctx: &'a LowerCtx<'a>, impl_trait: bool) -> Self {
+        let old = ctx.outer_impl_trait.replace(impl_trait);
+        Self { ctx, old }
+    }
+}
+
+impl<'a> Drop for OuterImplTraitGuard<'a> {
+    fn drop(&mut self) {
+        self.ctx.outer_impl_trait.replace(self.old);
+    }
 }
 
 impl<'a> LowerCtx<'a> {
@@ -28,6 +48,7 @@ impl<'a> LowerCtx<'a> {
             span_map: OnceCell::new(),
             ast_id_map: OnceCell::new(),
             impl_trait_bounds: RefCell::new(Vec::new()),
+            outer_impl_trait: RefCell::default(),
         }
     }
 
@@ -42,6 +63,7 @@ impl<'a> LowerCtx<'a> {
             span_map,
             ast_id_map: OnceCell::new(),
             impl_trait_bounds: RefCell::new(Vec::new()),
+            outer_impl_trait: RefCell::default(),
         }
     }
 
@@ -67,4 +89,12 @@ impl<'a> LowerCtx<'a> {
     pub fn take_impl_traits_bounds(&self) -> Vec<Vec<Interned<TypeBound>>> {
         self.impl_trait_bounds.take()
     }
+
+    pub(crate) fn outer_impl_trait(&self) -> bool {
+        *self.outer_impl_trait.borrow()
+    }
+
+    pub(crate) fn outer_impl_trait_scope(&'a self, impl_trait: bool) -> OuterImplTraitGuard<'a> {
+        OuterImplTraitGuard::new(self, impl_trait)
+    }
 }

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

@@ -36,6 +36,7 @@ macro_rules! m {
         let _ = 'c';
         let _ = 1000;
         let _ = 12E+99_f64;
+        let _ = 45E+1234_f128;
         let _ = "rust1";
         let _ = -92;
     }
@@ -50,6 +51,7 @@ macro_rules! m {
         let _ = 'c';
         let _ = 1000;
         let _ = 12E+99_f64;
+        let _ = 45E+1234_f128;
         let _ = "rust1";
         let _ = -92;
     }
@@ -58,6 +60,7 @@ fn f() {
     let _ = 'c';
     let _ = 1000;
     let _ = 12E+99_f64;
+    let _ = 45E+1234_f128;
     let _ = "rust1";
     let _ = -92;
 }

crates/hir-def/src/nameres.rs

@@ -103,12 +103,13 @@ const PREDEFINED_TOOLS: &[SmolStr] = &[
 /// is computed by the `block_def_map` query.
 #[derive(Debug, PartialEq, Eq)]
 pub struct DefMap {
+    /// The crate this `DefMap` belongs to.
+    krate: CrateId,
     /// When this is a block def map, this will hold the block id of the block and module that
     /// contains this block.
     block: Option<BlockInfo>,
     /// The modules and their data declared in this crate.
     pub modules: Arena<ModuleData>,
-    krate: CrateId,
     /// The prelude module for this crate. This either comes from an import
     /// marked with the `prelude_import` attribute, or (in the normal case) from
     /// a dependency (`std` or `core`).
@@ -124,6 +125,7 @@ pub struct DefMap {
 
     /// Tracks which custom derives are in scope for an item, to allow resolution of derive helper
     /// attributes.
+    // FIXME: Figure out a better way for the IDE layer to resolve these?
     derive_helpers_in_scope: FxHashMap<AstId<ast::Item>, Vec<(Name, MacroId, MacroCallId)>>,
 
     /// The diagnostics that need to be emitted for this crate.

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

@@ -83,7 +83,9 @@ pub(super) fn collect_defs(db: &dyn DefDatabase, def_map: DefMap, tree_id: TreeI
                     let name = Name::new_text_dont_use(it.name.clone());
                     (
                         name,
-                        if it.disabled {
+                        if !db.expand_proc_attr_macros() {
+                            CustomProcMacroExpander::dummy()
+                        } else if it.disabled {
                             CustomProcMacroExpander::disabled()
                         } else {
                             CustomProcMacroExpander::new(hir_expand::proc_macro::ProcMacroId::new(
@@ -1331,16 +1333,6 @@ impl DefCollector<'_> {
 
                     let call_id = call_id();
                     if let MacroDefKind::ProcMacro(_, exp, _) = def.kind {
-                        // If proc attribute macro expansion is disabled, skip expanding it here
-                        if !self.db.expand_proc_attr_macros() {
-                            self.def_map.diagnostics.push(DefDiagnostic::unresolved_proc_macro(
-                                directive.module_id,
-                                self.db.lookup_intern_macro_call(call_id).kind,
-                                def.krate,
-                            ));
-                            return recollect_without(self);
-                        }
-
                         // If there's no expander for the proc macro (e.g.
                         // because proc macros are disabled, or building the
                         // proc macro crate failed), report this and skip

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

@@ -17,16 +17,47 @@ use crate::{
 
 #[derive(Debug, PartialEq, Eq)]
 pub enum DefDiagnosticKind {
-    UnresolvedModule { ast: AstId<ast::Module>, candidates: Box<[String]> },
+    UnresolvedModule {
-    UnresolvedExternCrate { ast: AstId<ast::ExternCrate> },
+        ast: AstId<ast::Module>,
-    UnresolvedImport { id: ItemTreeId<item_tree::Use>, index: Idx<ast::UseTree> },
+        candidates: Box<[String]>,
-    UnconfiguredCode { ast: ErasedAstId, cfg: CfgExpr, opts: CfgOptions },
+    },
-    UnresolvedProcMacro { ast: MacroCallKind, krate: CrateId },
+    UnresolvedExternCrate {
-    UnresolvedMacroCall { ast: MacroCallKind, path: ModPath },
+        ast: AstId<ast::ExternCrate>,
-    UnimplementedBuiltinMacro { ast: AstId<ast::Macro> },
+    },
-    InvalidDeriveTarget { ast: AstId<ast::Item>, id: usize },
+    UnresolvedImport {
-    MalformedDerive { ast: AstId<ast::Adt>, id: usize },
+        id: ItemTreeId<item_tree::Use>,
-    MacroDefError { ast: AstId<ast::Macro>, message: String },
+        index: Idx<ast::UseTree>,
+    },
+    UnconfiguredCode {
+        ast: ErasedAstId,
+        cfg: CfgExpr,
+        opts: CfgOptions,
+    },
+    /// A proc-macro that is lacking an expander, this might be due to build scripts not yet having
+    /// run or proc-macro expansion being disabled.
+    UnresolvedProcMacro {
+        ast: MacroCallKind,
+        krate: CrateId,
+    },
+    UnresolvedMacroCall {
+        ast: MacroCallKind,
+        path: ModPath,
+    },
+    UnimplementedBuiltinMacro {
+        ast: AstId<ast::Macro>,
+    },
+    InvalidDeriveTarget {
+        ast: AstId<ast::Item>,
+        id: usize,
+    },
+    MalformedDerive {
+        ast: AstId<ast::Adt>,
+        id: usize,
+    },
+    MacroDefError {
+        ast: AstId<ast::Macro>,
+        message: String,
+    },
 }
 
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -92,10 +123,6 @@ impl DefDiagnostic {
         Self { in_module: container, kind: DefDiagnosticKind::UnconfiguredCode { ast, cfg, opts } }
     }
 
-    // FIXME: Whats the difference between this and unresolved_macro_call
-    // FIXME: This is used for a lot of things, unresolved proc macros, disabled proc macros, etc
-    // yet the diagnostic handler in ide-diagnostics has to figure out what happened because this
-    // struct loses all that information!
     pub fn unresolved_proc_macro(
         container: LocalModuleId,
         ast: MacroCallKind,

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

@@ -9,7 +9,7 @@ use hir_expand::{
     name::{name, AsName},
 };
 use intern::Interned;
-use syntax::ast::{self, AstNode, HasTypeBounds};
+use syntax::ast::{self, AstNode, HasGenericArgs, HasTypeBounds};
 
 use crate::{
     path::{AssociatedTypeBinding, GenericArg, GenericArgs, ModPath, Path, PathKind},
@@ -202,6 +202,8 @@ pub(super) fn lower_generic_args(
                     continue;
                 }
                 if let Some(name_ref) = assoc_type_arg.name_ref() {
+                    // Nested impl traits like `impl Foo<Assoc = impl Bar>` are allowed
+                    let _guard = lower_ctx.outer_impl_trait_scope(false);
                     let name = name_ref.as_name();
                     let args = assoc_type_arg
                         .generic_arg_list()

crates/hir-def/src/resolver.rs

@@ -596,7 +596,7 @@ impl Resolver {
                 Scope::GenericParams { params, def } => Some((params, def)),
                 _ => None,
             })
-            .flat_map(|(params, def)| params.where_predicates.iter().zip(iter::repeat(def)))
+            .flat_map(|(params, def)| params.where_predicates().zip(iter::repeat(def)))
     }
 
     pub fn generic_def(&self) -> Option<GenericDefId> {
@@ -758,10 +758,10 @@ impl Scope {
             }
             Scope::GenericParams { params, def: parent } => {
                 let parent = *parent;
-                for (local_id, param) in params.type_or_consts.iter() {
+                for (local_id, param) in params.iter_type_or_consts() {
                     if let Some(name) = &param.name() {
                         let id = TypeOrConstParamId { parent, local_id };
-                        let data = &db.generic_params(parent).type_or_consts[local_id];
+                        let data = &db.generic_params(parent)[local_id];
                         acc.add(
                             name,
                             ScopeDef::GenericParam(match data {
@@ -775,7 +775,7 @@ impl Scope {
                         );
                     }
                 }
-                for (local_id, param) in params.lifetimes.iter() {
+                for (local_id, param) in params.iter_lt() {
                     let id = LifetimeParamId { parent, local_id };
                     acc.add(&param.name, ScopeDef::GenericParam(id.into()))
                 }
@@ -1164,7 +1164,6 @@ impl HasResolver for GenericDefId {
             GenericDefId::TraitAliasId(inner) => inner.resolver(db),
             GenericDefId::TypeAliasId(inner) => inner.resolver(db),
             GenericDefId::ImplId(inner) => inner.resolver(db),
-            GenericDefId::EnumVariantId(inner) => inner.resolver(db),
             GenericDefId::ConstId(inner) => inner.resolver(db),
         }
     }

crates/hir-def/src/src.rs

@@ -64,7 +64,7 @@ impl HasChildSource<LocalTypeOrConstParamId> for GenericDefId {
         db: &dyn DefDatabase,
     ) -> InFile<ArenaMap<LocalTypeOrConstParamId, Self::Value>> {
         let generic_params = db.generic_params(*self);
-        let mut idx_iter = generic_params.type_or_consts.iter().map(|(idx, _)| idx);
+        let mut idx_iter = generic_params.iter_type_or_consts().map(|(idx, _)| idx);
 
         let (file_id, generic_params_list) = self.file_id_and_params_of(db);
 
@@ -103,7 +103,7 @@ impl HasChildSource<LocalLifetimeParamId> for GenericDefId {
         db: &dyn DefDatabase,
     ) -> InFile<ArenaMap<LocalLifetimeParamId, Self::Value>> {
         let generic_params = db.generic_params(*self);
-        let idx_iter = generic_params.lifetimes.iter().map(|(idx, _)| idx);
+        let idx_iter = generic_params.iter_lt().map(|(idx, _)| idx);
 
         let (file_id, generic_params_list) = self.file_id_and_params_of(db);
 

crates/hir-def/src/visibility.rs

@@ -2,6 +2,7 @@
 
 use std::iter;
 
+use intern::Interned;
 use la_arena::ArenaMap;
 use span::SyntaxContextId;
 use syntax::ast;
@@ -20,14 +21,17 @@ use crate::{
 pub enum RawVisibility {
     /// `pub(in module)`, `pub(crate)` or `pub(super)`. Also private, which is
     /// equivalent to `pub(self)`.
-    Module(ModPath, VisibilityExplicitness),
+    Module(Interned<ModPath>, VisibilityExplicitness),
     /// `pub`.
     Public,
 }
 
 impl RawVisibility {
-    pub(crate) const fn private() -> RawVisibility {
+    pub(crate) fn private() -> RawVisibility {
-        RawVisibility::Module(ModPath::from_kind(PathKind::SELF), VisibilityExplicitness::Implicit)
+        RawVisibility::Module(
+            Interned::new(ModPath::from_kind(PathKind::SELF)),
+            VisibilityExplicitness::Implicit,
+        )
     }
 
     pub(crate) fn from_ast(
@@ -60,7 +64,7 @@ impl RawVisibility {
             ast::VisibilityKind::PubSelf => ModPath::from_kind(PathKind::SELF),
             ast::VisibilityKind::Pub => return RawVisibility::Public,
         };
-        RawVisibility::Module(path, VisibilityExplicitness::Explicit)
+        RawVisibility::Module(Interned::new(path), VisibilityExplicitness::Explicit)
     }
 
     pub fn resolve(

crates/hir-expand/src/change.rs

@@ -25,7 +25,8 @@ impl ChangeWithProcMacros {
 
     pub fn apply(self, db: &mut (impl ExpandDatabase + SourceDatabaseExt)) {
         self.source_change.apply(db);
-        if let Some(proc_macros) = self.proc_macros {
+        if let Some(mut proc_macros) = self.proc_macros {
+            proc_macros.shrink_to_fit();
             db.set_proc_macros_with_durability(Arc::new(proc_macros), Durability::HIGH);
         }
         if let Some(target_data_layouts) = self.target_data_layouts {

crates/hir-expand/src/declarative.rs

@@ -172,15 +172,30 @@ impl DeclarativeMacroExpander {
             ),
             ast::Macro::MacroDef(macro_def) => (
                 match macro_def.body() {
-                    Some(arg) => {
+                    Some(body) => {
-                        let tt = mbe::syntax_node_to_token_tree(
+                        let span =
-                            arg.syntax(),
+                            map.span_for_range(macro_def.macro_token().unwrap().text_range());
+                        let args = macro_def.args().map(|args| {
+                            mbe::syntax_node_to_token_tree(
+                                args.syntax(),
+                                map.as_ref(),
+                                span,
+                                DocCommentDesugarMode::Mbe,
+                            )
+                        });
+                        let body = mbe::syntax_node_to_token_tree(
+                            body.syntax(),
                             map.as_ref(),
-                            map.span_for_range(macro_def.macro_token().unwrap().text_range()),
+                            span,
                             DocCommentDesugarMode::Mbe,
                         );
 
-                        mbe::DeclarativeMacro::parse_macro2(&tt, edition, new_meta_vars)
+                        mbe::DeclarativeMacro::parse_macro2(
+                            args.as_ref(),
+                            &body,
+                            edition,
+                            new_meta_vars,
+                        )
                     }
                     None => mbe::DeclarativeMacro::from_err(mbe::ParseError::Expected(
                         "expected a token tree".into(),

crates/hir-expand/src/files.rs

@@ -1,4 +1,6 @@
 //! Things to wrap other things in file ids.
+use std::borrow::Borrow;
+
 use either::Either;
 use span::{
     AstIdNode, ErasedFileAstId, FileAstId, FileId, FileRange, HirFileId, HirFileIdRepr,
@@ -76,6 +78,13 @@ impl<FileKind: Copy, T> InFileWrapper<FileKind, T> {
     pub fn as_ref(&self) -> InFileWrapper<FileKind, &T> {
         self.with_value(&self.value)
     }
+
+    pub fn borrow<U>(&self) -> InFileWrapper<FileKind, &U>
+    where
+        T: Borrow<U>,
+    {
+        self.with_value(self.value.borrow())
+    }
 }
 
 impl<FileKind: Copy, T: Clone> InFileWrapper<FileKind, &T> {
@@ -156,14 +165,61 @@ impl<FileId: Copy, N: AstNode> InFileWrapper<FileId, &N> {
 }
 
 // region:specific impls
+impl<SN: Borrow<SyntaxNode>> InRealFile<SN> {
+    pub fn file_range(&self) -> FileRange {
+        FileRange { file_id: self.file_id, range: self.value.borrow().text_range() }
+    }
+}
+
+impl<SN: Borrow<SyntaxNode>> InFile<SN> {
+    pub fn parent_ancestors_with_macros(
+        self,
+        db: &dyn db::ExpandDatabase,
+    ) -> impl Iterator<Item = InFile<SyntaxNode>> + '_ {
+        let succ = move |node: &InFile<SyntaxNode>| match node.value.parent() {
+            Some(parent) => Some(node.with_value(parent)),
+            None => db
+                .lookup_intern_macro_call(node.file_id.macro_file()?.macro_call_id)
+                .to_node_item(db)
+                .syntax()
+                .cloned()
+                .map(|node| node.parent())
+                .transpose(),
+        };
+        std::iter::successors(succ(&self.borrow().cloned()), succ)
+    }
+
+    pub fn ancestors_with_macros(
+        self,
+        db: &dyn db::ExpandDatabase,
+    ) -> impl Iterator<Item = InFile<SyntaxNode>> + '_ {
+        let succ = move |node: &InFile<SyntaxNode>| match node.value.parent() {
+            Some(parent) => Some(node.with_value(parent)),
+            None => db
+                .lookup_intern_macro_call(node.file_id.macro_file()?.macro_call_id)
+                .to_node_item(db)
+                .syntax()
+                .cloned()
+                .map(|node| node.parent())
+                .transpose(),
+        };
+        std::iter::successors(Some(self.borrow().cloned()), succ)
+    }
+
+    pub fn kind(&self) -> parser::SyntaxKind {
+        self.value.borrow().kind()
+    }
+
+    pub fn text_range(&self) -> TextRange {
+        self.value.borrow().text_range()
+    }
 
-impl InFile<&SyntaxNode> {
     /// Falls back to the macro call range if the node cannot be mapped up fully.
     ///
     /// For attributes and derives, this will point back to the attribute only.
     /// For the entire item use [`InFile::original_file_range_full`].
     pub fn original_file_range_rooted(self, db: &dyn db::ExpandDatabase) -> FileRange {
-        self.map(SyntaxNode::text_range).original_node_file_range_rooted(db)
+        self.borrow().map(SyntaxNode::text_range).original_node_file_range_rooted(db)
     }
 
     /// Falls back to the macro call range if the node cannot be mapped up fully.
@@ -171,15 +227,7 @@ impl InFile<&SyntaxNode> {
         self,
         db: &dyn db::ExpandDatabase,
     ) -> FileRange {
-        self.map(SyntaxNode::text_range).original_node_file_range_with_macro_call_body(db)
+        self.borrow().map(SyntaxNode::text_range).original_node_file_range_with_macro_call_body(db)
-    }
-
-    /// Attempts to map the syntax node back up its macro calls.
-    pub fn original_file_range_opt(
-        self,
-        db: &dyn db::ExpandDatabase,
-    ) -> Option<(FileRange, SyntaxContextId)> {
-        self.map(SyntaxNode::text_range).original_node_file_range_opt(db)
     }
 
     pub fn original_syntax_node_rooted(
@@ -190,16 +238,19 @@ impl InFile<&SyntaxNode> {
         // as we don't have node inputs otherwise and therefore can't find an `N` node in the input
         let file_id = match self.file_id.repr() {
             HirFileIdRepr::FileId(file_id) => {
-                return Some(InRealFile { file_id, value: self.value.clone() })
+                return Some(InRealFile { file_id, value: self.value.borrow().clone() })
             }
             HirFileIdRepr::MacroFile(m) if m.is_attr_macro(db) => m,
             _ => return None,
         };
 
-        let FileRange { file_id, range } =
+        let FileRange { file_id, range } = map_node_range_up_rooted(
-            map_node_range_up_rooted(db, &db.expansion_span_map(file_id), self.value.text_range())?;
+            db,
+            &db.expansion_span_map(file_id),
+            self.value.borrow().text_range(),
+        )?;
 
-        let kind = self.value.kind();
+        let kind = self.kind();
         let value = db
             .parse(file_id)
             .syntax_node()
@@ -211,6 +262,16 @@ impl InFile<&SyntaxNode> {
     }
 }
 
+impl InFile<&SyntaxNode> {
+    /// Attempts to map the syntax node back up its macro calls.
+    pub fn original_file_range_opt(
+        self,
+        db: &dyn db::ExpandDatabase,
+    ) -> Option<(FileRange, SyntaxContextId)> {
+        self.borrow().map(SyntaxNode::text_range).original_node_file_range_opt(db)
+    }
+}
+
 impl InMacroFile<SyntaxToken> {
     pub fn upmap_once(
         self,

crates/hir-expand/src/lib.rs

@@ -4,7 +4,6 @@
 //! tree originates not from the text of some `FileId`, but from some macro
 //! expansion.
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
-#![warn(rust_2018_idioms, unused_lifetimes)]
 
 pub mod attrs;
 pub mod builtin_attr_macro;

crates/hir-expand/src/name.rs

@@ -275,8 +275,10 @@ pub mod known {
         u32,
         u64,
         u128,
+        f16,
         f32,
         f64,
+        f128,
         bool,
         char,
         str,

crates/hir-ty/Cargo.toml

@@ -33,6 +33,7 @@ triomphe.workspace = true
 nohash-hasher.workspace = true
 typed-arena = "2.0.1"
 indexmap.workspace = true
+rustc_apfloat = "0.2.0"
 
 ra-ap-rustc_abi.workspace = true
 ra-ap-rustc_index.workspace = true

crates/hir-ty/src/builder.rs

@@ -63,7 +63,14 @@ impl<D> TyBuilder<D> {
     }
 
     fn build_internal(self) -> (D, Substitution) {
-        assert_eq!(self.vec.len(), self.param_kinds.len(), "{:?}", &self.param_kinds);
+        assert_eq!(
+            self.vec.len(),
+            self.param_kinds.len(),
+            "{} args received, {} expected ({:?})",
+            self.vec.len(),
+            self.param_kinds.len(),
+            &self.param_kinds
+        );
         for (a, e) in self.vec.iter().zip(self.param_kinds.iter()) {
             self.assert_match_kind(a, e);
         }
@@ -252,8 +259,9 @@ impl TyBuilder<()> {
     /// This method prepopulates the builder with placeholder substitution of `parent`, so you
     /// should only push exactly 3 `GenericArg`s before building.
     pub fn subst_for_coroutine(db: &dyn HirDatabase, parent: DefWithBodyId) -> TyBuilder<()> {
-        let parent_subst =
+        let parent_subst = parent
-            parent.as_generic_def_id().map(|p| generics(db.upcast(), p).placeholder_subst(db));
+            .as_generic_def_id(db.upcast())
+            .map(|p| generics(db.upcast(), p).placeholder_subst(db));
         // These represent resume type, yield type, and return type of coroutine.
         let params = std::iter::repeat(ParamKind::Type).take(3).collect();
         TyBuilder::new((), params, parent_subst)
@@ -266,7 +274,7 @@ impl TyBuilder<()> {
     ) -> Substitution {
         let sig_ty = sig_ty.cast(Interner);
         let self_subst = iter::once(&sig_ty);
-        let Some(parent) = parent.as_generic_def_id() else {
+        let Some(parent) = parent.as_generic_def_id(db.upcast()) else {
             return Substitution::from_iter(Interner, self_subst);
         };
         Substitution::from_iter(
@@ -296,7 +304,8 @@ impl TyBuilder<hir_def::AdtId> {
     ) -> Self {
         // Note that we're building ADT, so we never have parent generic parameters.
         let defaults = db.generic_defaults(self.data.into());
-        for default_ty in defaults.iter().skip(self.vec.len()) {
+
+        for default_ty in &defaults[self.vec.len()..] {
             // NOTE(skip_binders): we only check if the arg type is error type.
             if let Some(x) = default_ty.skip_binders().ty(Interner) {
                 if x.is_unknown() {

crates/hir-ty/src/chalk_db.rs

@@ -13,7 +13,8 @@ use hir_def::{
     data::adt::StructFlags,
     hir::Movability,
     lang_item::{LangItem, LangItemTarget},
-    AssocItemId, BlockId, GenericDefId, HasModule, ItemContainerId, Lookup, TypeAliasId, VariantId,
+    AssocItemId, BlockId, CallableDefId, GenericDefId, HasModule, ItemContainerId, Lookup,
+    TypeAliasId, VariantId,
 };
 use hir_expand::name::name;
 
@@ -28,9 +29,9 @@ use crate::{
     to_assoc_type_id, to_chalk_trait_id,
     traits::ChalkContext,
     utils::ClosureSubst,
-    wrap_empty_binders, AliasEq, AliasTy, BoundVar, CallableDefId, DebruijnIndex, FnDefId,
+    wrap_empty_binders, AliasEq, AliasTy, BoundVar, DebruijnIndex, FnDefId, Interner, ProjectionTy,
-    Interner, ProjectionTy, ProjectionTyExt, QuantifiedWhereClause, Substitution, TraitRef,
+    ProjectionTyExt, QuantifiedWhereClause, Substitution, TraitRef, TraitRefExt, Ty, TyBuilder,
-    TraitRefExt, Ty, TyBuilder, TyExt, TyKind, WhereClause,
+    TyExt, TyKind, WhereClause,
 };
 
 pub(crate) type AssociatedTyDatum = chalk_solve::rust_ir::AssociatedTyDatum<Interner>;
@@ -102,7 +103,7 @@ impl chalk_solve::RustIrDatabase<Interner> for ChalkContext<'_> {
         &self,
         fn_def_id: chalk_ir::FnDefId<Interner>,
     ) -> Arc<rust_ir::FnDefDatum<Interner>> {
-        self.db.fn_def_datum(self.krate, fn_def_id)
+        self.db.fn_def_datum(fn_def_id)
     }
 
     fn impls_for_trait(
@@ -912,16 +913,13 @@ fn type_alias_associated_ty_value(
     Arc::new(value)
 }
 
-pub(crate) fn fn_def_datum_query(
+pub(crate) fn fn_def_datum_query(db: &dyn HirDatabase, fn_def_id: FnDefId) -> Arc<FnDefDatum> {
-    db: &dyn HirDatabase,
-    _krate: CrateId,
-    fn_def_id: FnDefId,
-) -> Arc<FnDefDatum> {
     let callable_def: CallableDefId = from_chalk(db, fn_def_id);
-    let generic_params = generics(db.upcast(), callable_def.into());
+    let generic_def = GenericDefId::from_callable(db.upcast(), callable_def);
+    let generic_params = generics(db.upcast(), generic_def);
     let (sig, binders) = db.callable_item_signature(callable_def).into_value_and_skipped_binders();
     let bound_vars = generic_params.bound_vars_subst(db, DebruijnIndex::INNERMOST);
-    let where_clauses = convert_where_clauses(db, callable_def.into(), &bound_vars);
+    let where_clauses = convert_where_clauses(db, generic_def, &bound_vars);
     let bound = rust_ir::FnDefDatumBound {
         // Note: Chalk doesn't actually use this information yet as far as I am aware, but we provide it anyway
         inputs_and_output: chalk_ir::Binders::empty(
@@ -948,7 +946,8 @@ pub(crate) fn fn_def_datum_query(
 
 pub(crate) fn fn_def_variance_query(db: &dyn HirDatabase, fn_def_id: FnDefId) -> Variances {
     let callable_def: CallableDefId = from_chalk(db, fn_def_id);
-    let generic_params = generics(db.upcast(), callable_def.into());
+    let generic_params =
+        generics(db.upcast(), GenericDefId::from_callable(db.upcast(), callable_def));
     Variances::from_iter(
         Interner,
         std::iter::repeat(chalk_ir::Variance::Invariant).take(generic_params.len()),

crates/hir-ty/src/chalk_ext.rs

@@ -119,8 +119,10 @@ impl TyExt for Ty {
             TyKind::Scalar(Scalar::Bool) => Some(BuiltinType::Bool),
             TyKind::Scalar(Scalar::Char) => Some(BuiltinType::Char),
             TyKind::Scalar(Scalar::Float(fty)) => Some(BuiltinType::Float(match fty {
+                FloatTy::F128 => BuiltinFloat::F128,
                 FloatTy::F64 => BuiltinFloat::F64,
                 FloatTy::F32 => BuiltinFloat::F32,
+                FloatTy::F16 => BuiltinFloat::F16,
             })),
             TyKind::Scalar(Scalar::Int(ity)) => Some(BuiltinType::Int(match ity {
                 IntTy::Isize => BuiltinInt::Isize,
@@ -188,9 +190,10 @@ impl TyExt for Ty {
     fn as_generic_def(&self, db: &dyn HirDatabase) -> Option<GenericDefId> {
         match *self.kind(Interner) {
             TyKind::Adt(AdtId(adt), ..) => Some(adt.into()),
-            TyKind::FnDef(callable, ..) => {
+            TyKind::FnDef(callable, ..) => Some(GenericDefId::from_callable(
-                Some(db.lookup_intern_callable_def(callable.into()).into())
+                db.upcast(),
-            }
+                db.lookup_intern_callable_def(callable.into()),
+            )),
             TyKind::AssociatedType(type_alias, ..) => Some(from_assoc_type_id(type_alias).into()),
             TyKind::Foreign(type_alias, ..) => Some(from_foreign_def_id(type_alias).into()),
             _ => None,
@@ -308,7 +311,7 @@ impl TyExt for Ty {
             TyKind::Placeholder(idx) => {
                 let id = from_placeholder_idx(db, *idx);
                 let generic_params = db.generic_params(id.parent);
-                let param_data = &generic_params.type_or_consts[id.local_id];
+                let param_data = &generic_params[id.local_id];
                 match param_data {
                     TypeOrConstParamData::TypeParamData(p) => match p.provenance {
                         hir_def::generics::TypeParamProvenance::ArgumentImplTrait => {

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

@@ -1,6 +1,10 @@
 use base_db::FileId;
 use chalk_ir::Substitution;
 use hir_def::db::DefDatabase;
+use rustc_apfloat::{
+    ieee::{Half as f16, Quad as f128},
+    Float,
+};
 use test_fixture::WithFixture;
 use test_utils::skip_slow_tests;
 
@@ -140,6 +144,14 @@ fn bit_op() {
 
 #[test]
 fn floating_point() {
+    check_number(
+        r#"const GOAL: f128 = 2.0 + 3.0 * 5.5 - 8.;"#,
+        "10.5".parse::<f128>().unwrap().to_bits() as i128,
+    );
+    check_number(
+        r#"const GOAL: f128 = -90.0 + 36.0;"#,
+        "-54.0".parse::<f128>().unwrap().to_bits() as i128,
+    );
     check_number(
         r#"const GOAL: f64 = 2.0 + 3.0 * 5.5 - 8.;"#,
         i128::from_le_bytes(pad16(&f64::to_le_bytes(10.5), true)),
@@ -152,6 +164,20 @@ fn floating_point() {
         r#"const GOAL: f32 = -90.0 + 36.0;"#,
         i128::from_le_bytes(pad16(&f32::to_le_bytes(-54.0), true)),
     );
+    check_number(
+        r#"const GOAL: f16 = 2.0 + 3.0 * 5.5 - 8.;"#,
+        i128::from_le_bytes(pad16(
+            &u16::try_from("10.5".parse::<f16>().unwrap().to_bits()).unwrap().to_le_bytes(),
+            true,
+        )),
+    );
+    check_number(
+        r#"const GOAL: f16 = -90.0 + 36.0;"#,
+        i128::from_le_bytes(pad16(
+            &u16::try_from("-54.0".parse::<f16>().unwrap().to_bits()).unwrap().to_le_bytes(),
+            true,
+        )),
+    );
 }
 
 #[test]

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

@@ -411,6 +411,7 @@ fn likely() {
 
 #[test]
 fn floating_point() {
+    // FIXME(#17451): Add `f16` and `f128` tests once intrinsics are added.
     check_number(
         r#"
         extern "rust-intrinsic" {
@@ -426,6 +427,7 @@ fn floating_point() {
             true,
         )),
     );
+    #[allow(unknown_lints, clippy::unnecessary_min_or_max)]
     check_number(
         r#"
         extern "rust-intrinsic" {

crates/hir-ty/src/db.rs

@@ -9,8 +9,8 @@ use base_db::{
     CrateId, Upcast,
 };
 use hir_def::{
-    db::DefDatabase, hir::ExprId, layout::TargetDataLayout, AdtId, BlockId, ConstParamId,
+    db::DefDatabase, hir::ExprId, layout::TargetDataLayout, AdtId, BlockId, CallableDefId,
-    DefWithBodyId, EnumVariantId, FunctionId, GeneralConstId, GenericDefId, ImplId,
+    ConstParamId, DefWithBodyId, EnumVariantId, FunctionId, GeneralConstId, GenericDefId, ImplId,
     LifetimeParamId, LocalFieldId, StaticId, TypeAliasId, TypeOrConstParamId, VariantId,
 };
 use la_arena::ArenaMap;
@@ -24,9 +24,8 @@ use crate::{
     lower::{GenericDefaults, GenericPredicates},
     method_resolution::{InherentImpls, TraitImpls, TyFingerprint},
     mir::{BorrowckResult, MirBody, MirLowerError},
-    Binders, CallableDefId, ClosureId, Const, FnDefId, ImplTraitId, ImplTraits, InferenceResult,
+    Binders, ClosureId, Const, FnDefId, ImplTraitId, ImplTraits, InferenceResult, Interner,
-    Interner, PolyFnSig, QuantifiedWhereClause, Substitution, TraitEnvironment, TraitRef, Ty,
+    PolyFnSig, Substitution, TraitEnvironment, TraitRef, Ty, TyDefId, ValueTyDefId,
-    TyDefId, ValueTyDefId,
 };
 use hir_expand::name::Name;
 
@@ -81,8 +80,32 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     #[salsa::cycle(crate::consteval::const_eval_discriminant_recover)]
     fn const_eval_discriminant(&self, def: EnumVariantId) -> Result<i128, ConstEvalError>;
 
+    #[salsa::invoke(crate::method_resolution::lookup_impl_method_query)]
+    fn lookup_impl_method(
+        &self,
+        env: Arc<TraitEnvironment>,
+        func: FunctionId,
+        fn_subst: Substitution,
+    ) -> (FunctionId, Substitution);
+
     // endregion:mir
 
+    #[salsa::invoke(crate::layout::layout_of_adt_query)]
+    #[salsa::cycle(crate::layout::layout_of_adt_recover)]
+    fn layout_of_adt(
+        &self,
+        def: AdtId,
+        subst: Substitution,
+        env: Arc<TraitEnvironment>,
+    ) -> Result<Arc<Layout>, LayoutError>;
+
+    #[salsa::invoke(crate::layout::layout_of_ty_query)]
+    #[salsa::cycle(crate::layout::layout_of_ty_recover)]
+    fn layout_of_ty(&self, ty: Ty, env: Arc<TraitEnvironment>) -> Result<Arc<Layout>, LayoutError>;
+
+    #[salsa::invoke(crate::layout::target_data_layout_query)]
+    fn target_data_layout(&self, krate: CrateId) -> Result<Arc<TargetDataLayout>, Arc<str>>;
+
     #[salsa::invoke(crate::lower::ty_query)]
     #[salsa::cycle(crate::lower::ty_recover)]
     fn ty(&self, def: TyDefId) -> Binders<Ty>;
@@ -105,30 +128,6 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     #[salsa::invoke(crate::lower::field_types_query)]
     fn field_types(&self, var: VariantId) -> Arc<ArenaMap<LocalFieldId, Binders<Ty>>>;
 
-    #[salsa::invoke(crate::layout::layout_of_adt_query)]
-    #[salsa::cycle(crate::layout::layout_of_adt_recover)]
-    fn layout_of_adt(
-        &self,
-        def: AdtId,
-        subst: Substitution,
-        env: Arc<TraitEnvironment>,
-    ) -> Result<Arc<Layout>, LayoutError>;
-
-    #[salsa::invoke(crate::layout::layout_of_ty_query)]
-    #[salsa::cycle(crate::layout::layout_of_ty_recover)]
-    fn layout_of_ty(&self, ty: Ty, env: Arc<TraitEnvironment>) -> Result<Arc<Layout>, LayoutError>;
-
-    #[salsa::invoke(crate::layout::target_data_layout_query)]
-    fn target_data_layout(&self, krate: CrateId) -> Result<Arc<TargetDataLayout>, Arc<str>>;
-
-    #[salsa::invoke(crate::method_resolution::lookup_impl_method_query)]
-    fn lookup_impl_method(
-        &self,
-        env: Arc<TraitEnvironment>,
-        func: FunctionId,
-        fn_subst: Substitution,
-    ) -> (FunctionId, Substitution);
-
     #[salsa::invoke(crate::lower::callable_item_sig)]
     fn callable_item_signature(&self, def: CallableDefId) -> PolyFnSig;
 
@@ -145,7 +144,7 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
         def: GenericDefId,
         param_id: TypeOrConstParamId,
         assoc_name: Option<Name>,
-    ) -> Arc<[Binders<QuantifiedWhereClause>]>;
+    ) -> GenericPredicates;
 
     #[salsa::invoke(crate::lower::generic_predicates_query)]
     fn generic_predicates(&self, def: GenericDefId) -> GenericPredicates;
@@ -232,7 +231,7 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     ) -> sync::Arc<chalk_db::ImplDatum>;
 
     #[salsa::invoke(chalk_db::fn_def_datum_query)]
-    fn fn_def_datum(&self, krate: CrateId, fn_def_id: FnDefId) -> sync::Arc<chalk_db::FnDefDatum>;
+    fn fn_def_datum(&self, fn_def_id: FnDefId) -> sync::Arc<chalk_db::FnDefDatum>;
 
     #[salsa::invoke(chalk_db::fn_def_variance_query)]
     fn fn_def_variance(&self, fn_def_id: FnDefId) -> chalk_db::Variances;

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

@@ -196,6 +196,9 @@ impl ExprValidator {
             let Some(pat_ty) = self.infer.type_of_pat.get(arm.pat) else {
                 return;
             };
+            if pat_ty.contains_unknown() {
+                return;
+            }
 
             // We only include patterns whose type matches the type
             // of the scrutinee expression. If we had an InvalidMatchArmPattern

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

@@ -51,6 +51,7 @@ pub(crate) struct Pat {
 #[derive(Clone, Debug, PartialEq)]
 pub(crate) enum PatKind {
     Wild,
+    Never,
 
     /// `x`, `ref x`, `x @ P`, etc.
     Binding {
@@ -294,6 +295,7 @@ impl HirDisplay for Pat {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
         match &*self.kind {
             PatKind::Wild => write!(f, "_"),
+            PatKind::Never => write!(f, "!"),
             PatKind::Binding { name, subpattern } => {
                 write!(f, "{}", name.display(f.db.upcast()))?;
                 if let Some(subpattern) = subpattern {

crates/hir-ty/src/diagnostics/match_check/pat_analysis.rs

@@ -4,12 +4,10 @@ use std::fmt;
 
 use hir_def::{DefWithBodyId, EnumId, EnumVariantId, HasModule, LocalFieldId, ModuleId, VariantId};
 use once_cell::unsync::Lazy;
-use rustc_hash::FxHashMap;
 use rustc_pattern_analysis::{
     constructor::{Constructor, ConstructorSet, VariantVisibility},
-    index::IdxContainer,
     usefulness::{compute_match_usefulness, PlaceValidity, UsefulnessReport},
-    Captures, PatCx, PrivateUninhabitedField,
+    Captures, IndexVec, PatCx, PrivateUninhabitedField,
 };
 use smallvec::{smallvec, SmallVec};
 use stdx::never;
@@ -26,10 +24,10 @@ use super::{is_box, FieldPat, Pat, PatKind};
 use Constructor::*;
 
 // Re-export r-a-specific versions of all these types.
-pub(crate) type DeconstructedPat<'p> =
+pub(crate) type DeconstructedPat<'db> =
-    rustc_pattern_analysis::pat::DeconstructedPat<MatchCheckCtx<'p>>;
+    rustc_pattern_analysis::pat::DeconstructedPat<MatchCheckCtx<'db>>;
-pub(crate) type MatchArm<'p> = rustc_pattern_analysis::MatchArm<'p, MatchCheckCtx<'p>>;
+pub(crate) type MatchArm<'db> = rustc_pattern_analysis::MatchArm<'db, MatchCheckCtx<'db>>;
-pub(crate) type WitnessPat<'p> = rustc_pattern_analysis::pat::WitnessPat<MatchCheckCtx<'p>>;
+pub(crate) type WitnessPat<'db> = rustc_pattern_analysis::pat::WitnessPat<MatchCheckCtx<'db>>;
 
 /// [Constructor] uses this in unimplemented variants.
 /// It allows porting match expressions from upstream algorithm without losing semantics.
@@ -54,23 +52,27 @@ impl EnumVariantContiguousIndex {
     }
 }
 
+impl rustc_pattern_analysis::Idx for EnumVariantContiguousIndex {
+    fn new(idx: usize) -> Self {
+        EnumVariantContiguousIndex(idx)
+    }
+
+    fn index(self) -> usize {
+        self.0
+    }
+}
+
 #[derive(Clone)]
-pub(crate) struct MatchCheckCtx<'p> {
+pub(crate) struct MatchCheckCtx<'db> {
     module: ModuleId,
     body: DefWithBodyId,
-    pub(crate) db: &'p dyn HirDatabase,
+    pub(crate) db: &'db dyn HirDatabase,
     exhaustive_patterns: bool,
     min_exhaustive_patterns: bool,
 }
 
-#[derive(Clone)]
+impl<'db> MatchCheckCtx<'db> {
-pub(crate) struct PatData<'p> {
+    pub(crate) fn new(module: ModuleId, body: DefWithBodyId, db: &'db dyn HirDatabase) -> Self {
-    /// Keep db around so that we can print variant names in `Debug`.
-    pub(crate) db: &'p dyn HirDatabase,
-}
-
-impl<'p> MatchCheckCtx<'p> {
-    pub(crate) fn new(module: ModuleId, body: DefWithBodyId, db: &'p dyn HirDatabase) -> Self {
         let def_map = db.crate_def_map(module.krate());
         let exhaustive_patterns = def_map.is_unstable_feature_enabled("exhaustive_patterns");
         let min_exhaustive_patterns =
@@ -80,9 +82,9 @@ impl<'p> MatchCheckCtx<'p> {
 
     pub(crate) fn compute_match_usefulness(
         &self,
-        arms: &[MatchArm<'p>],
+        arms: &[MatchArm<'db>],
         scrut_ty: Ty,
-    ) -> Result<UsefulnessReport<'p, Self>, ()> {
+    ) -> Result<UsefulnessReport<'db, Self>, ()> {
         // FIXME: Determine place validity correctly. For now, err on the safe side.
         let place_validity = PlaceValidity::MaybeInvalid;
         // Measured to take ~100ms on modern hardware.
@@ -101,7 +103,7 @@ impl<'p> MatchCheckCtx<'p> {
     }
 
     fn variant_id_for_adt(
-        db: &'p dyn HirDatabase,
+        db: &'db dyn HirDatabase,
         ctor: &Constructor<Self>,
         adt: hir_def::AdtId,
     ) -> Option<VariantId> {
@@ -126,7 +128,7 @@ impl<'p> MatchCheckCtx<'p> {
         &'a self,
         ty: &'a Ty,
         variant: VariantId,
-    ) -> impl Iterator<Item = (LocalFieldId, Ty)> + Captures<'a> + Captures<'p> {
+    ) -> impl Iterator<Item = (LocalFieldId, Ty)> + Captures<'a> + Captures<'db> {
         let (_, substs) = ty.as_adt().unwrap();
 
         let field_tys = self.db.field_types(variant);
@@ -139,8 +141,8 @@ impl<'p> MatchCheckCtx<'p> {
         })
     }
 
-    pub(crate) fn lower_pat(&self, pat: &Pat) -> DeconstructedPat<'p> {
+    pub(crate) fn lower_pat(&self, pat: &Pat) -> DeconstructedPat<'db> {
-        let singleton = |pat: DeconstructedPat<'p>| vec![pat.at_index(0)];
+        let singleton = |pat: DeconstructedPat<'db>| vec![pat.at_index(0)];
         let ctor;
         let mut fields: Vec<_>;
         let arity;
@@ -228,6 +230,11 @@ impl<'p> MatchCheckCtx<'p> {
                 fields = Vec::new();
                 arity = 0;
             }
+            PatKind::Never => {
+                ctor = Never;
+                fields = Vec::new();
+                arity = 0;
+            }
             PatKind::Or { pats } => {
                 ctor = Or;
                 fields = pats
@@ -238,11 +245,10 @@ impl<'p> MatchCheckCtx<'p> {
                 arity = pats.len();
             }
         }
-        let data = PatData { db: self.db };
+        DeconstructedPat::new(ctor, fields, arity, pat.ty.clone(), ())
-        DeconstructedPat::new(ctor, fields, arity, pat.ty.clone(), data)
     }
 
-    pub(crate) fn hoist_witness_pat(&self, pat: &WitnessPat<'p>) -> Pat {
+    pub(crate) fn hoist_witness_pat(&self, pat: &WitnessPat<'db>) -> Pat {
         let mut subpatterns = pat.iter_fields().map(|p| self.hoist_witness_pat(p));
         let kind = match pat.ctor() {
             &Bool(value) => PatKind::LiteralBool { value },
@@ -290,6 +296,7 @@ impl<'p> MatchCheckCtx<'p> {
             Slice(_) => unimplemented!(),
             &Str(void) => match void {},
             Wildcard | NonExhaustive | Hidden | PrivateUninhabited => PatKind::Wild,
+            Never => PatKind::Never,
             Missing | F32Range(..) | F64Range(..) | Opaque(..) | Or => {
                 never!("can't convert to pattern: {:?}", pat.ctor());
                 PatKind::Wild
@@ -299,13 +306,13 @@ impl<'p> MatchCheckCtx<'p> {
     }
 }
 
-impl<'p> PatCx for MatchCheckCtx<'p> {
+impl<'db> PatCx for MatchCheckCtx<'db> {
     type Error = ();
     type Ty = Ty;
     type VariantIdx = EnumVariantContiguousIndex;
     type StrLit = Void;
     type ArmData = ();
-    type PatData = PatData<'p>;
+    type PatData = ();
 
     fn is_exhaustive_patterns_feature_on(&self) -> bool {
         self.exhaustive_patterns
@@ -339,8 +346,8 @@ impl<'p> PatCx for MatchCheckCtx<'p> {
             },
             Ref => 1,
             Slice(..) => unimplemented!(),
-            Bool(..) | IntRange(..) | F32Range(..) | F64Range(..) | Str(..) | Opaque(..)
+            Never | Bool(..) | IntRange(..) | F32Range(..) | F64Range(..) | Str(..)
-            | NonExhaustive | PrivateUninhabited | Hidden | Missing | Wildcard => 0,
+            | Opaque(..) | NonExhaustive | PrivateUninhabited | Hidden | Missing | Wildcard => 0,
             Or => {
                 never!("The `Or` constructor doesn't have a fixed arity");
                 0
@@ -402,8 +409,10 @@ impl<'p> PatCx for MatchCheckCtx<'p> {
                 }
             },
             Slice(_) => unreachable!("Found a `Slice` constructor in match checking"),
-            Bool(..) | IntRange(..) | F32Range(..) | F64Range(..) | Str(..) | Opaque(..)
+            Never | Bool(..) | IntRange(..) | F32Range(..) | F64Range(..) | Str(..)
-            | NonExhaustive | PrivateUninhabited | Hidden | Missing | Wildcard => smallvec![],
+            | Opaque(..) | NonExhaustive | PrivateUninhabited | Hidden | Missing | Wildcard => {
+                smallvec![]
+            }
             Or => {
                 never!("called `Fields::wildcards` on an `Or` ctor");
                 smallvec![]
@@ -442,11 +451,8 @@ impl<'p> PatCx for MatchCheckCtx<'p> {
                 if enum_data.variants.is_empty() && !is_declared_nonexhaustive {
                     ConstructorSet::NoConstructors
                 } else {
-                    let mut variants = FxHashMap::with_capacity_and_hasher(
+                    let mut variants = IndexVec::with_capacity(enum_data.variants.len());
-                        enum_data.variants.len(),
+                    for &(variant, _) in enum_data.variants.iter() {
-                        Default::default(),
-                    );
-                    for (i, &(variant, _)) in enum_data.variants.iter().enumerate() {
                         let is_uninhabited =
                             is_enum_variant_uninhabited_from(cx.db, variant, subst, cx.module);
                         let visibility = if is_uninhabited {
@@ -454,13 +460,10 @@ impl<'p> PatCx for MatchCheckCtx<'p> {
                         } else {
                             VariantVisibility::Visible
                         };
-                        variants.insert(EnumVariantContiguousIndex(i), visibility);
+                        variants.push(visibility);
                     }
 
-                    ConstructorSet::Variants {
+                    ConstructorSet::Variants { variants, non_exhaustive: is_declared_nonexhaustive }
-                        variants: IdxContainer(variants),
-                        non_exhaustive: is_declared_nonexhaustive,
-                    }
                 }
             }
             TyKind::Adt(AdtId(hir_def::AdtId::UnionId(_)), _) => ConstructorSet::Union,
@@ -476,26 +479,27 @@ impl<'p> PatCx for MatchCheckCtx<'p> {
 
     fn write_variant_name(
         f: &mut fmt::Formatter<'_>,
-        pat: &rustc_pattern_analysis::pat::DeconstructedPat<Self>,
+        _ctor: &Constructor<Self>,
+        _ty: &Self::Ty,
     ) -> fmt::Result {
-        let db = pat.data().db;
+        write!(f, "<write_variant_name unsupported>")
-        let variant =
+        // We lack the database here ...
-            pat.ty().as_adt().and_then(|(adt, _)| Self::variant_id_for_adt(db, pat.ctor(), adt));
+        // let variant = ty.as_adt().and_then(|(adt, _)| Self::variant_id_for_adt(db, ctor, adt));
 
-        if let Some(variant) = variant {
+        // if let Some(variant) = variant {
-            match variant {
+        //     match variant {
-                VariantId::EnumVariantId(v) => {
+        //         VariantId::EnumVariantId(v) => {
-                    write!(f, "{}", db.enum_variant_data(v).name.display(db.upcast()))?;
+        //             write!(f, "{}", db.enum_variant_data(v).name.display(db.upcast()))?;
-                }
+        //         }
-                VariantId::StructId(s) => {
+        //         VariantId::StructId(s) => {
-                    write!(f, "{}", db.struct_data(s).name.display(db.upcast()))?
+        //             write!(f, "{}", db.struct_data(s).name.display(db.upcast()))?
-                }
+        //         }
-                VariantId::UnionId(u) => {
+        //         VariantId::UnionId(u) => {
-                    write!(f, "{}", db.union_data(u).name.display(db.upcast()))?
+        //             write!(f, "{}", db.union_data(u).name.display(db.upcast()))?
-                }
+        //         }
-            }
+        //     }
-        }
+        // }
-        Ok(())
+        // Ok(())
     }
 
     fn bug(&self, fmt: fmt::Arguments<'_>) {
@@ -507,7 +511,7 @@ impl<'p> PatCx for MatchCheckCtx<'p> {
     }
 }
 
-impl<'p> fmt::Debug for MatchCheckCtx<'p> {
+impl<'db> fmt::Debug for MatchCheckCtx<'db> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("MatchCheckCtx").finish()
     }

crates/hir-ty/src/display.rs

@@ -21,13 +21,17 @@ use hir_def::{
     path::{Path, PathKind},
     type_ref::{TraitBoundModifier, TypeBound, TypeRef},
     visibility::Visibility,
-    HasModule, ImportPathConfig, ItemContainerId, LocalFieldId, Lookup, ModuleDefId, ModuleId,
+    GenericDefId, HasModule, ImportPathConfig, ItemContainerId, LocalFieldId, Lookup, ModuleDefId,
-    TraitId,
+    ModuleId, TraitId,
 };
 use hir_expand::name::Name;
 use intern::{Internable, Interned};
 use itertools::Itertools;
 use la_arena::ArenaMap;
+use rustc_apfloat::{
+    ieee::{Half as f16, Quad as f128},
+    Float,
+};
 use smallvec::SmallVec;
 use stdx::{never, IsNoneOr};
 use triomphe::Arc;
@@ -545,6 +549,17 @@ fn render_const_scalar(
                 write!(f, "{it}")
             }
             Scalar::Float(fl) => match fl {
+                chalk_ir::FloatTy::F16 => {
+                    // FIXME(#17451): Replace with builtins once they are stabilised.
+                    let it = f16::from_bits(u16::from_le_bytes(b.try_into().unwrap()).into());
+                    let s = it.to_string();
+                    if s.strip_prefix('-').unwrap_or(&s).chars().all(|c| c.is_ascii_digit()) {
+                        // Match Rust debug formatting
+                        write!(f, "{s}.0")
+                    } else {
+                        write!(f, "{s}")
+                    }
+                }
                 chalk_ir::FloatTy::F32 => {
                     let it = f32::from_le_bytes(b.try_into().unwrap());
                     write!(f, "{it:?}")
@@ -553,6 +568,17 @@ fn render_const_scalar(
                     let it = f64::from_le_bytes(b.try_into().unwrap());
                     write!(f, "{it:?}")
                 }
+                chalk_ir::FloatTy::F128 => {
+                    // FIXME(#17451): Replace with builtins once they are stabilised.
+                    let it = f128::from_bits(u128::from_le_bytes(b.try_into().unwrap()));
+                    let s = it.to_string();
+                    if s.strip_prefix('-').unwrap_or(&s).chars().all(|c| c.is_ascii_digit()) {
+                        // Match Rust debug formatting
+                        write!(f, "{s}.0")
+                    } else {
+                        write!(f, "{s}")
+                    }
+                }
             },
         },
         TyKind::Ref(_, _, t) => match t.kind(Interner) {
@@ -988,7 +1014,8 @@ impl HirDisplay for Ty {
                 f.end_location_link();
 
                 if parameters.len(Interner) > 0 {
-                    let generics = generics(db.upcast(), def.into());
+                    let generic_def_id = GenericDefId::from_callable(db.upcast(), def);
+                    let generics = generics(db.upcast(), generic_def_id);
                     let (parent_len, self_param, type_, const_, impl_, lifetime) =
                         generics.provenance_split();
                     let parameters = parameters.as_slice(Interner);
@@ -1002,8 +1029,9 @@ impl HirDisplay for Ty {
                         debug_assert_eq!(parent_params.len(), parent_len);
 
                         let parent_params =
-                            generic_args_sans_defaults(f, Some(def.into()), parent_params);
+                            generic_args_sans_defaults(f, Some(generic_def_id), parent_params);
-                        let fn_params = generic_args_sans_defaults(f, Some(def.into()), fn_params);
+                        let fn_params =
+                            generic_args_sans_defaults(f, Some(generic_def_id), fn_params);
 
                         write!(f, "<")?;
                         hir_fmt_generic_arguments(f, parent_params, None)?;
@@ -1041,7 +1069,11 @@ impl HirDisplay for Ty {
                             module_id,
                             PrefixKind::Plain,
                             false,
-                            ImportPathConfig { prefer_no_std: false, prefer_prelude: true },
+                            ImportPathConfig {
+                                prefer_no_std: false,
+                                prefer_prelude: true,
+                                prefer_absolute: false,
+                            },
                         ) {
                             write!(f, "{}", path.display(f.db.upcast()))?;
                         } else {

crates/hir-ty/src/generics.rs

@@ -2,8 +2,8 @@
 //!
 //! The layout for generics as expected by chalk are as follows:
 //! - Optional Self parameter
-//! - Type or Const parameters
 //! - Lifetime parameters
+//! - Type or Const parameters
 //! - Parent parameters
 //!
 //! where parent follows the same scheme.
@@ -20,18 +20,23 @@ use hir_def::{
     LocalLifetimeParamId, LocalTypeOrConstParamId, Lookup, TypeOrConstParamId, TypeParamId,
 };
 use intern::Interned;
+use itertools::chain;
+use stdx::TupleExt;
 
 use crate::{db::HirDatabase, lt_to_placeholder_idx, to_placeholder_idx, Interner, Substitution};
 
 pub(crate) fn generics(db: &dyn DefDatabase, def: GenericDefId) -> Generics {
     let parent_generics = parent_generic_def(db, def).map(|def| Box::new(generics(db, def)));
-    Generics { def, params: db.generic_params(def), parent_generics }
+    let params = db.generic_params(def);
+    let has_trait_self_param = params.trait_self_param().is_some();
+    Generics { def, params, parent_generics, has_trait_self_param }
 }
 #[derive(Clone, Debug)]
 pub(crate) struct Generics {
     def: GenericDefId,
     params: Interned<GenericParams>,
     parent_generics: Option<Box<Generics>>,
+    has_trait_self_param: bool,
 }
 
 impl<T> ops::Index<T> for Generics
@@ -57,7 +62,7 @@ impl Generics {
         self.iter_self().map(|(id, _)| id)
     }
 
-    fn iter_parent_id(&self) -> impl Iterator<Item = GenericParamId> + '_ {
+    pub(crate) fn iter_parent_id(&self) -> impl Iterator<Item = GenericParamId> + '_ {
         self.iter_parent().map(|(id, _)| id)
     }
 
@@ -67,6 +72,12 @@ impl Generics {
         self.params.iter_type_or_consts()
     }
 
+    pub(crate) fn iter_self_type_or_consts_id(
+        &self,
+    ) -> impl DoubleEndedIterator<Item = GenericParamId> + '_ {
+        self.params.iter_type_or_consts().map(from_toc_id(self)).map(TupleExt::head)
+    }
+
     /// Iterate over the params followed by the parent params.
     pub(crate) fn iter(
         &self,
@@ -78,10 +89,9 @@ impl Generics {
     pub(crate) fn iter_self(
         &self,
     ) -> impl DoubleEndedIterator<Item = (GenericParamId, GenericParamDataRef<'_>)> + '_ {
-        self.params
+        let mut toc = self.params.iter_type_or_consts().map(from_toc_id(self));
-            .iter_type_or_consts()
+        let trait_self_param = self.has_trait_self_param.then(|| toc.next()).flatten();
-            .map(from_toc_id(self))
+        chain!(trait_self_param, self.params.iter_lt().map(from_lt_id(self)), toc)
-            .chain(self.params.iter_lt().map(from_lt_id(self)))
     }
 
     /// Iterator over types and const params of parent.
@@ -89,8 +99,9 @@ impl Generics {
         &self,
     ) -> impl DoubleEndedIterator<Item = (GenericParamId, GenericParamDataRef<'_>)> + '_ {
         self.parent_generics().into_iter().flat_map(|it| {
-            let lt_iter = it.params.iter_lt().map(from_lt_id(it));
+            let mut toc = it.params.iter_type_or_consts().map(from_toc_id(it));
-            it.params.iter_type_or_consts().map(from_toc_id(it)).chain(lt_iter)
+            let trait_self_param = it.has_trait_self_param.then(|| toc.next()).flatten();
+            chain!(trait_self_param, it.params.iter_lt().map(from_lt_id(it)), toc)
         })
     }
 
@@ -134,8 +145,11 @@ impl Generics {
     fn find_type_or_const_param(&self, param: TypeOrConstParamId) -> Option<usize> {
         if param.parent == self.def {
             let idx = param.local_id.into_raw().into_u32() as usize;
-            debug_assert!(idx <= self.params.type_or_consts.len());
+            debug_assert!(idx <= self.params.len_type_or_consts());
-            Some(idx)
+            if self.params.trait_self_param() == Some(param.local_id) {
+                return Some(idx);
+            }
+            Some(self.params.len_lifetimes() + idx)
         } else {
             debug_assert_eq!(self.parent_generics().map(|it| it.def), Some(param.parent));
             self.parent_generics()
@@ -152,8 +166,8 @@ impl Generics {
     fn find_lifetime(&self, lifetime: LifetimeParamId) -> Option<usize> {
         if lifetime.parent == self.def {
             let idx = lifetime.local_id.into_raw().into_u32() as usize;
-            debug_assert!(idx <= self.params.lifetimes.len());
+            debug_assert!(idx <= self.params.len_lifetimes());
-            Some(self.params.type_or_consts.len() + idx)
+            Some(self.params.trait_self_param().is_some() as usize + idx)
         } else {
             debug_assert_eq!(self.parent_generics().map(|it| it.def), Some(lifetime.parent));
             self.parent_generics()
@@ -216,7 +230,6 @@ fn parent_generic_def(db: &dyn DefDatabase, def: GenericDefId) -> Option<Generic
         GenericDefId::FunctionId(it) => it.lookup(db).container,
         GenericDefId::TypeAliasId(it) => it.lookup(db).container,
         GenericDefId::ConstId(it) => it.lookup(db).container,
-        GenericDefId::EnumVariantId(it) => return Some(it.lookup(db).parent.into()),
         GenericDefId::AdtId(_)
         | GenericDefId::TraitId(_)
         | GenericDefId::ImplId(_)

crates/hir-ty/src/infer.rs

@@ -701,18 +701,23 @@ impl<'a> InferenceContext<'a> {
         table.propagate_diverging_flag();
         for ty in type_of_expr.values_mut() {
             *ty = table.resolve_completely(ty.clone());
+            *has_errors = *has_errors || ty.contains_unknown();
         }
         for ty in type_of_pat.values_mut() {
             *ty = table.resolve_completely(ty.clone());
+            *has_errors = *has_errors || ty.contains_unknown();
         }
         for ty in type_of_binding.values_mut() {
             *ty = table.resolve_completely(ty.clone());
+            *has_errors = *has_errors || ty.contains_unknown();
         }
         for ty in type_of_rpit.values_mut() {
             *ty = table.resolve_completely(ty.clone());
+            *has_errors = *has_errors || ty.contains_unknown();
         }
         for ty in type_of_for_iterator.values_mut() {
             *ty = table.resolve_completely(ty.clone());
+            *has_errors = *has_errors || ty.contains_unknown();
         }
 
         *has_errors = !type_mismatches.is_empty();
@@ -835,11 +840,7 @@ impl<'a> InferenceContext<'a> {
         let return_ty = if let Some(rpits) = self.db.return_type_impl_traits(func) {
             // RPIT opaque types use substitution of their parent function.
             let fn_placeholders = TyBuilder::placeholder_subst(self.db, func);
-            let result = self.insert_inference_vars_for_impl_trait(
+            let result = self.insert_inference_vars_for_impl_trait(return_ty, fn_placeholders);
-                return_ty,
-                rpits.clone(),
-                fn_placeholders,
-            );
             let rpits = rpits.skip_binders();
             for (id, _) in rpits.impl_traits.iter() {
                 if let Entry::Vacant(e) = self.result.type_of_rpit.entry(id) {
@@ -862,12 +863,7 @@ impl<'a> InferenceContext<'a> {
         self.insert_atpit_coercion_table(params_and_ret_tys.iter());
     }
 
-    fn insert_inference_vars_for_impl_trait<T>(
+    fn insert_inference_vars_for_impl_trait<T>(&mut self, t: T, placeholders: Substitution) -> T
-        &mut self,
-        t: T,
-        rpits: Arc<chalk_ir::Binders<crate::ImplTraits>>,
-        placeholders: Substitution,
-    ) -> T
     where
         T: crate::HasInterner<Interner = Interner> + crate::TypeFoldable<Interner>,
     {
@@ -878,13 +874,21 @@ impl<'a> InferenceContext<'a> {
                     TyKind::OpaqueType(opaque_ty_id, _) => *opaque_ty_id,
                     _ => return ty,
                 };
-                let idx = match self.db.lookup_intern_impl_trait_id(opaque_ty_id.into()) {
+                let (impl_traits, idx) =
-                    ImplTraitId::ReturnTypeImplTrait(_, idx) => idx,
+                    match self.db.lookup_intern_impl_trait_id(opaque_ty_id.into()) {
-                    ImplTraitId::AssociatedTypeImplTrait(_, idx) => idx,
+                        ImplTraitId::ReturnTypeImplTrait(def, idx) => {
-                    _ => unreachable!(),
+                            (self.db.return_type_impl_traits(def), idx)
+                        }
+                        ImplTraitId::AssociatedTypeImplTrait(def, idx) => {
+                            (self.db.type_alias_impl_traits(def), idx)
+                        }
+                        _ => unreachable!(),
+                    };
+                let Some(impl_traits) = impl_traits else {
+                    return ty;
                 };
-                let bounds =
+                let bounds = (*impl_traits)
-                    (*rpits).map_ref(|rpits| rpits.impl_traits[idx].bounds.map_ref(|it| it.iter()));
+                    .map_ref(|rpits| rpits.impl_traits[idx].bounds.map_ref(|it| it.iter()));
                 let var = self.table.new_type_var();
                 let var_subst = Substitution::from1(Interner, var.clone());
                 for bound in bounds {
@@ -892,11 +896,8 @@ impl<'a> InferenceContext<'a> {
                     let (var_predicate, binders) =
                         predicate.substitute(Interner, &var_subst).into_value_and_skipped_binders();
                     always!(binders.is_empty(Interner)); // quantified where clauses not yet handled
-                    let var_predicate = self.insert_inference_vars_for_impl_trait(
+                    let var_predicate = self
-                        var_predicate,
+                        .insert_inference_vars_for_impl_trait(var_predicate, placeholders.clone());
-                        rpits.clone(),
-                        placeholders.clone(),
-                    );
                     self.push_obligation(var_predicate.cast(Interner));
                 }
                 self.result.type_of_rpit.insert(idx, var.clone());
@@ -983,16 +984,8 @@ impl<'a> InferenceContext<'a> {
                     self.db.lookup_intern_impl_trait_id(opaque_ty_id.into())
                 {
                     if assoc_tys.contains(&alias_id) {
-                        let atpits = self
-                            .db
-                            .type_alias_impl_traits(alias_id)
-                            .expect("Marked as ATPIT but no impl traits!");
                         let alias_placeholders = TyBuilder::placeholder_subst(self.db, alias_id);
-                        let ty = self.insert_inference_vars_for_impl_trait(
+                        let ty = self.insert_inference_vars_for_impl_trait(ty, alias_placeholders);
-                            ty,
-                            atpits,
-                            alias_placeholders,
-                        );
                         return Some((opaque_ty_id, ty));
                     }
                 }

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

@@ -13,7 +13,7 @@ use hir_def::{
     },
     lang_item::{LangItem, LangItemTarget},
     path::{GenericArgs, Path},
-    BlockId, FieldId, GenericParamId, ItemContainerId, Lookup, TupleFieldId, TupleId,
+    BlockId, FieldId, GenericDefId, GenericParamId, ItemContainerId, Lookup, TupleFieldId, TupleId,
 };
 use hir_expand::name::{name, Name};
 use stdx::always;
@@ -440,7 +440,8 @@ impl InferenceContext<'_> {
                 let ty = match self.infer_path(p, tgt_expr.into()) {
                     Some(ty) => ty,
                     None => {
-                        if matches!(p, Path::Normal { mod_path, .. } if mod_path.is_ident()) {
+                        if matches!(p, Path::Normal { mod_path, .. } if mod_path.is_ident() || mod_path.is_self())
+                        {
                             self.push_diagnostic(InferenceDiagnostic::UnresolvedIdent {
                                 expr: tgt_expr,
                             });
@@ -1895,7 +1896,8 @@ impl InferenceContext<'_> {
         let callable_ty = self.resolve_ty_shallow(callable_ty);
         if let TyKind::FnDef(fn_def, parameters) = callable_ty.kind(Interner) {
             let def: CallableDefId = from_chalk(self.db, *fn_def);
-            let generic_predicates = self.db.generic_predicates(def.into());
+            let generic_predicates =
+                self.db.generic_predicates(GenericDefId::from_callable(self.db.upcast(), def));
             for predicate in generic_predicates.iter() {
                 let (predicate, binders) = predicate
                     .clone()

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

@@ -41,14 +41,7 @@ impl InferenceContext<'_> {
     fn resolve_value_path(&mut self, path: &Path, id: ExprOrPatId) -> Option<ValuePathResolution> {
         let (value, self_subst) = self.resolve_value_path_inner(path, id)?;
 
-        let value_def = match value {
+        let value_def: ValueTyDefId = match value {
-            ValueNs::LocalBinding(pat) => match self.result.type_of_binding.get(pat) {
-                Some(ty) => return Some(ValuePathResolution::NonGeneric(ty.clone())),
-                None => {
-                    never!("uninferred pattern?");
-                    return None;
-                }
-            },
             ValueNs::FunctionId(it) => it.into(),
             ValueNs::ConstId(it) => it.into(),
             ValueNs::StaticId(it) => it.into(),
@@ -62,48 +55,79 @@ impl InferenceContext<'_> {
 
                 it.into()
             }
+            ValueNs::LocalBinding(pat) => {
+                return match self.result.type_of_binding.get(pat) {
+                    Some(ty) => Some(ValuePathResolution::NonGeneric(ty.clone())),
+                    None => {
+                        never!("uninferred pattern?");
+                        None
+                    }
+                }
+            }
             ValueNs::ImplSelf(impl_id) => {
                 let generics = crate::generics::generics(self.db.upcast(), impl_id.into());
                 let substs = generics.placeholder_subst(self.db);
                 let ty = self.db.impl_self_ty(impl_id).substitute(Interner, &substs);
-                if let Some((AdtId::StructId(struct_id), substs)) = ty.as_adt() {
+                return if let Some((AdtId::StructId(struct_id), substs)) = ty.as_adt() {
-                    return Some(ValuePathResolution::GenericDef(
+                    Some(ValuePathResolution::GenericDef(
                         struct_id.into(),
                         struct_id.into(),
                         substs.clone(),
-                    ));
+                    ))
                 } else {
                     // FIXME: report error, invalid Self reference
-                    return None;
+                    None
-                }
+                };
             }
             ValueNs::GenericParam(it) => {
                 return Some(ValuePathResolution::NonGeneric(self.db.const_param_ty(it)))
             }
         };
 
+        let generic_def_id = value_def.to_generic_def_id(self.db);
+        let Some(generic_def) = generic_def_id else {
+            // `value_def` is the kind of item that can never be generic (i.e. statics, at least
+            // currently). We can just skip the binders to get its type.
+            let (ty, binders) = self.db.value_ty(value_def)?.into_value_and_skipped_binders();
+            stdx::always!(binders.is_empty(Interner), "non-empty binders for non-generic def",);
+            return Some(ValuePathResolution::NonGeneric(ty));
+        };
+
         let ctx = crate::lower::TyLoweringContext::new(self.db, &self.resolver, self.owner.into());
         let substs = ctx.substs_from_path(path, value_def, true);
         let substs = substs.as_slice(Interner);
+
+        if let ValueNs::EnumVariantId(_) = value {
+            let mut it = self_subst
+                .as_ref()
+                .map_or(&[][..], |s| s.as_slice(Interner))
+                .iter()
+                .chain(substs)
+                .cloned();
+            let builder = TyBuilder::subst_for_def(self.db, generic_def, None);
+            let substs = builder
+                .fill(|x| {
+                    it.next().unwrap_or_else(|| match x {
+                        ParamKind::Type => {
+                            self.result.standard_types.unknown.clone().cast(Interner)
+                        }
+                        ParamKind::Const(ty) => consteval::unknown_const_as_generic(ty.clone()),
+                        ParamKind::Lifetime => error_lifetime().cast(Interner),
+                    })
+                })
+                .build();
+
+            return Some(ValuePathResolution::GenericDef(value_def, generic_def, substs));
+        }
+
         let parent_substs = self_subst.or_else(|| {
-            let generics = generics(self.db.upcast(), value_def.to_generic_def_id()?);
+            let generics = generics(self.db.upcast(), generic_def_id?);
             let parent_params_len = generics.parent_generics()?.len();
             let parent_args = &substs[substs.len() - parent_params_len..];
             Some(Substitution::from_iter(Interner, parent_args))
         });
         let parent_substs_len = parent_substs.as_ref().map_or(0, |s| s.len(Interner));
         let mut it = substs.iter().take(substs.len() - parent_substs_len).cloned();
-
-        let Some(generic_def) = value_def.to_generic_def_id() else {
-            // `value_def` is the kind of item that can never be generic (i.e. statics, at least
-            // currently). We can just skip the binders to get its type.
-            let (ty, binders) = self.db.value_ty(value_def)?.into_value_and_skipped_binders();
-            stdx::always!(
-                parent_substs.is_none() && binders.is_empty(Interner),
-                "non-empty binders for non-generic def",
-            );
-            return Some(ValuePathResolution::NonGeneric(ty));
-        };
         let builder = TyBuilder::subst_for_def(self.db, generic_def, parent_substs);
         let substs = builder
             .fill(|x| {

crates/hir-ty/src/layout.rs

@@ -265,8 +265,10 @@ pub fn layout_of_ty_query(
             chalk_ir::Scalar::Float(f) => scalar(
                 dl,
                 Primitive::Float(match f {
+                    FloatTy::F16 => Float::F16,
                     FloatTy::F32 => Float::F32,
                     FloatTy::F64 => Float::F64,
+                    FloatTy::F128 => Float::F128,
                 }),
             ),
         },

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

@@ -426,6 +426,7 @@ fn enums() {
 
 #[test]
 fn primitives() {
+    // FIXME(#17451): Add `f16` and `f128` once they are stabilised.
     size_and_align! {
         struct Goal(i32, i128, isize, usize, f32, f64, bool, char);
     }

crates/hir-ty/src/lib.rs

@@ -1,6 +1,6 @@
 //! The type system. We currently use this to infer types for completion, hover
 //! information and various assists.
-#![warn(rust_2018_idioms, unused_lifetimes)]
+
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 
 #[cfg(feature = "in-rust-tree")]
@@ -60,7 +60,7 @@ use chalk_ir::{
     NoSolution,
 };
 use either::Either;
-use hir_def::{hir::ExprId, type_ref::Rawness, GeneralConstId, TypeOrConstParamId};
+use hir_def::{hir::ExprId, type_ref::Rawness, CallableDefId, GeneralConstId, TypeOrConstParamId};
 use hir_expand::name;
 use la_arena::{Arena, Idx};
 use mir::{MirEvalError, VTableMap};
@@ -84,8 +84,8 @@ pub use infer::{
 };
 pub use interner::Interner;
 pub use lower::{
-    associated_type_shorthand_candidates, CallableDefId, ImplTraitLoweringMode, ParamLoweringMode,
+    associated_type_shorthand_candidates, ImplTraitLoweringMode, ParamLoweringMode, TyDefId,
-    TyDefId, TyLoweringContext, ValueTyDefId,
+    TyLoweringContext, ValueTyDefId,
 };
 pub use mapping::{
     from_assoc_type_id, from_chalk_trait_id, from_foreign_def_id, from_placeholder_idx,

crates/hir-ty/src/lower.rs

@@ -11,10 +11,7 @@ use std::{
     ops::{self, Not as _},
 };
 
-use base_db::{
+use base_db::{salsa::Cycle, CrateId};
-    salsa::{Cycle, InternValueTrivial},
-    CrateId,
-};
 use chalk_ir::{
     cast::Cast,
     fold::{Shift, TypeFoldable},
@@ -38,10 +35,10 @@ use hir_def::{
     type_ref::{
         ConstRef, LifetimeRef, TraitBoundModifier, TraitRef as HirTraitRef, TypeBound, TypeRef,
     },
-    AdtId, AssocItemId, ConstId, ConstParamId, DefWithBodyId, EnumId, EnumVariantId, FunctionId,
+    AdtId, AssocItemId, CallableDefId, ConstId, ConstParamId, DefWithBodyId, EnumId, EnumVariantId,
-    GenericDefId, GenericParamId, HasModule, ImplId, InTypeConstLoc, ItemContainerId, LocalFieldId,
+    FunctionId, GenericDefId, GenericParamId, HasModule, ImplId, InTypeConstLoc, ItemContainerId,
-    Lookup, ModuleDefId, StaticId, StructId, TraitId, TypeAliasId, TypeOrConstParamId, TypeOwnerId,
+    LocalFieldId, Lookup, StaticId, StructId, TraitId, TypeAliasId, TypeOrConstParamId,
-    UnionId, VariantId,
+    TypeOwnerId, UnionId, VariantId,
 };
 use hir_expand::{name::Name, ExpandResult};
 use intern::Interned;
@@ -387,14 +384,18 @@ impl<'a> TyLoweringContext<'a> {
                             type_params,
                             const_params,
                             _impl_trait_params,
-                            _lifetime_params,
+                            lifetime_params,
                         ) = self
                             .generics()
                             .expect("variable impl trait lowering must be in a generic def")
                             .provenance_split();
                         TyKind::BoundVar(BoundVar::new(
                             self.in_binders,
-                            idx as usize + self_param as usize + type_params + const_params,
+                            idx as usize
+                                + self_param as usize
+                                + type_params
+                                + const_params
+                                + lifetime_params,
                         ))
                         .intern(Interner)
                     }
@@ -815,13 +816,13 @@ impl<'a> TyLoweringContext<'a> {
         infer_args: bool,
         explicit_self_ty: Option<Ty>,
     ) -> Substitution {
-        // Remember that the item's own generic args come before its parent's.
+        let Some(def) = def else { return Substitution::empty(Interner) };
-        let mut substs = Vec::new();
+
-        let def = if let Some(d) = def {
+        // Order is
-            d
+        // - Optional Self parameter
-        } else {
+        // - Lifetime parameters
-            return Substitution::empty(Interner);
+        // - Type or Const parameters
-        };
+        // - Parent parameters
         let def_generics = generics(self.db.upcast(), def);
         let (
             parent_params,
@@ -835,130 +836,121 @@ impl<'a> TyLoweringContext<'a> {
             self_param as usize + type_params + const_params + impl_trait_params + lifetime_params;
         let total_len = parent_params + item_len;
 
-        let ty_error = TyKind::Error.intern(Interner).cast(Interner);
+        let mut substs = Vec::new();
 
-        let mut def_generic_iter = def_generics.iter_id();
+        // we need to iterate the lifetime and type/const params separately as our order of them
+        // differs from the supplied syntax
 
-        let fill_self_params = || {
+        let ty_error = || TyKind::Error.intern(Interner).cast(Interner);
+        let mut def_toc_iter = def_generics.iter_self_type_or_consts_id();
+        let fill_self_param = || {
             if self_param {
-                let self_ty =
+                let self_ty = explicit_self_ty.map(|x| x.cast(Interner)).unwrap_or_else(ty_error);
-                    explicit_self_ty.map(|x| x.cast(Interner)).unwrap_or_else(|| ty_error.clone());
 
-                if let Some(id) = def_generic_iter.next() {
+                if let Some(id) = def_toc_iter.next() {
-                    assert!(matches!(
+                    assert!(matches!(id, GenericParamId::TypeParamId(_)));
-                        id,
-                        GenericParamId::TypeParamId(_) | GenericParamId::LifetimeParamId(_)
-                    ));
                     substs.push(self_ty);
                 }
             }
         };
         let mut had_explicit_args = false;
 
-        if let Some(generic_args) = &args_and_bindings {
+        if let Some(&GenericArgs { ref args, has_self_type, .. }) = args_and_bindings {
-            if !generic_args.has_self_type {
+            // Fill in the self param first
-                fill_self_params();
+            if has_self_type && self_param {
-            }
+                had_explicit_args = true;
-            let expected_num = if generic_args.has_self_type {
+                if let Some(id) = def_toc_iter.next() {
-                self_param as usize + type_params + const_params
+                    assert!(matches!(id, GenericParamId::TypeParamId(_)));
+                    had_explicit_args = true;
+                    if let GenericArg::Type(ty) = &args[0] {
+                        substs.push(self.lower_ty(ty).cast(Interner));
+                    }
+                }
             } else {
-                type_params + const_params
+                fill_self_param()
             };
-            let skip = if generic_args.has_self_type && !self_param { 1 } else { 0 };
+
-            // if args are provided, it should be all of them, but we can't rely on that
+            // Then fill in the supplied lifetime args, or error lifetimes if there are too few
-            for arg in generic_args
+            // (default lifetimes aren't a thing)
-                .args
+            for arg in args
+                .iter()
+                .filter_map(|arg| match arg {
+                    GenericArg::Lifetime(arg) => Some(self.lower_lifetime(arg)),
+                    _ => None,
+                })
+                .chain(iter::repeat(error_lifetime()))
+                .take(lifetime_params)
+            {
+                substs.push(arg.cast(Interner));
+            }
+
+            let skip = if has_self_type { 1 } else { 0 };
+            // Fill in supplied type and const args
+            // Note if non-lifetime args are provided, it should be all of them, but we can't rely on that
+            for (arg, id) in args
                 .iter()
                 .filter(|arg| !matches!(arg, GenericArg::Lifetime(_)))
                 .skip(skip)
-                .take(expected_num)
+                .take(type_params + const_params)
+                .zip(def_toc_iter)
             {
-                if let Some(id) = def_generic_iter.next() {
+                had_explicit_args = true;
-                    let arg = generic_arg_to_chalk(
+                let arg = generic_arg_to_chalk(
-                        self.db,
+                    self.db,
-                        id,
+                    id,
-                        arg,
+                    arg,
-                        &mut (),
+                    &mut (),
-                        |_, type_ref| self.lower_ty(type_ref),
+                    |_, type_ref| self.lower_ty(type_ref),
-                        |_, const_ref, ty| self.lower_const(const_ref, ty),
+                    |_, const_ref, ty| self.lower_const(const_ref, ty),
-                        |_, lifetime_ref| self.lower_lifetime(lifetime_ref),
+                    |_, lifetime_ref| self.lower_lifetime(lifetime_ref),
-                    );
+                );
-                    had_explicit_args = true;
+                substs.push(arg);
-                    substs.push(arg);
-                }
-            }
-
-            for arg in generic_args
-                .args
-                .iter()
-                .filter(|arg| matches!(arg, GenericArg::Lifetime(_)))
-                .take(lifetime_params)
-            {
-                // Taking into the fact that def_generic_iter will always have lifetimes at the end
-                // Should have some test cases tho to test this behaviour more properly
-                if let Some(id) = def_generic_iter.next() {
-                    let arg = generic_arg_to_chalk(
-                        self.db,
-                        id,
-                        arg,
-                        &mut (),
-                        |_, type_ref| self.lower_ty(type_ref),
-                        |_, const_ref, ty| self.lower_const(const_ref, ty),
-                        |_, lifetime_ref| self.lower_lifetime(lifetime_ref),
-                    );
-                    had_explicit_args = true;
-                    substs.push(arg);
-                }
             }
         } else {
-            fill_self_params();
+            fill_self_param();
         }
 
-        // These params include those of parent.
+        let param_to_err = |id| match id {
-        let remaining_params: SmallVec<[_; 2]> = def_generic_iter
+            GenericParamId::ConstParamId(x) => unknown_const_as_generic(self.db.const_param_ty(x)),
-            .map(|id| match id {
+            GenericParamId::TypeParamId(_) => ty_error(),
-                GenericParamId::ConstParamId(x) => {
+            GenericParamId::LifetimeParamId(_) => error_lifetime().cast(Interner),
-                    unknown_const_as_generic(self.db.const_param_ty(x))
+        };
-                }
-                GenericParamId::TypeParamId(_) => ty_error.clone(),
-                GenericParamId::LifetimeParamId(_) => error_lifetime().cast(Interner),
-            })
-            .collect();
-        assert_eq!(remaining_params.len() + substs.len(), total_len);
-
         // handle defaults. In expression or pattern path segments without
         // explicitly specified type arguments, missing type arguments are inferred
         // (i.e. defaults aren't used).
         // Generic parameters for associated types are not supposed to have defaults, so we just
         // ignore them.
-        let is_assoc_ty = if let GenericDefId::TypeAliasId(id) = def {
+        let is_assoc_ty = || match def {
-            let container = id.lookup(self.db.upcast()).container;
+            GenericDefId::TypeAliasId(id) => {
-            matches!(container, ItemContainerId::TraitId(_))
+                matches!(id.lookup(self.db.upcast()).container, ItemContainerId::TraitId(_))
-        } else {
+            }
-            false
+            _ => false,
         };
-        if !is_assoc_ty && (!infer_args || had_explicit_args) {
+        let fill_defaults = (!infer_args || had_explicit_args) && !is_assoc_ty();
-            let defaults = self.db.generic_defaults(def);
+        if fill_defaults {
-            assert_eq!(total_len, defaults.len());
+            let defaults = &*self.db.generic_defaults(def);
+            let (item, _parent) = defaults.split_at(item_len);
             let parent_from = item_len - substs.len();
 
-            for (idx, default_ty) in defaults[substs.len()..item_len].iter().enumerate() {
+            let mut rem =
+                def_generics.iter_id().skip(substs.len()).map(param_to_err).collect::<Vec<_>>();
+            // Fill in defaults for type/const params
+            for (idx, default_ty) in item[substs.len()..].iter().enumerate() {
                 // each default can depend on the previous parameters
                 let substs_so_far = Substitution::from_iter(
                     Interner,
-                    substs.iter().cloned().chain(remaining_params[idx..].iter().cloned()),
+                    substs.iter().cloned().chain(rem[idx..].iter().cloned()),
                 );
                 substs.push(default_ty.clone().substitute(Interner, &substs_so_far));
             }
-
+            // Fill in remaining parent params
-            // Keep parent's params as unknown.
+            substs.extend(rem.drain(parent_from..));
-            let mut remaining_params = remaining_params;
-            substs.extend(remaining_params.drain(parent_from..));
         } else {
-            substs.extend(remaining_params);
+            // Fill in remaining def params and parent params
+            substs.extend(def_generics.iter_id().skip(substs.len()).map(param_to_err));
         }
 
-        assert_eq!(substs.len(), total_len);
+        assert_eq!(substs.len(), total_len, "expected {} substs, got {}", total_len, substs.len());
         Substitution::from_iter(Interner, substs)
     }
 
@@ -1535,7 +1527,7 @@ pub(crate) fn generic_predicates_for_param_query(
     def: GenericDefId,
     param_id: TypeOrConstParamId,
     assoc_name: Option<Name>,
-) -> Arc<[Binders<QuantifiedWhereClause>]> {
+) -> GenericPredicates {
     let resolver = def.resolver(db.upcast());
     let ctx = if let GenericDefId::FunctionId(_) = def {
         TyLoweringContext::new(db, &resolver, def.into())
@@ -1611,7 +1603,7 @@ pub(crate) fn generic_predicates_for_param_query(
             );
         };
     }
-    predicates.into()
+    GenericPredicates(predicates.is_empty().not().then(|| predicates.into()))
 }
 
 pub(crate) fn generic_predicates_for_param_recover(
@@ -1620,15 +1612,15 @@ pub(crate) fn generic_predicates_for_param_recover(
     _def: &GenericDefId,
     _param_id: &TypeOrConstParamId,
     _assoc_name: &Option<Name>,
-) -> Arc<[Binders<QuantifiedWhereClause>]> {
+) -> GenericPredicates {
-    Arc::from_iter(None)
+    GenericPredicates(None)
 }
 
 pub(crate) fn trait_environment_for_body_query(
     db: &dyn HirDatabase,
     def: DefWithBodyId,
 ) -> Arc<TraitEnvironment> {
-    let Some(def) = def.as_generic_def_id() else {
+    let Some(def) = def.as_generic_def_id(db.upcast()) else {
         let krate = def.module(db.upcast()).krate();
         return TraitEnvironment::empty(krate);
     };
@@ -1725,8 +1717,8 @@ pub(crate) fn generic_predicates_query(
         })
         .collect::<Vec<_>>();
 
-    let subst = generics.bound_vars_subst(db, DebruijnIndex::INNERMOST);
+    if generics.len() > 0 {
-    if !subst.is_empty(Interner) {
+        let subst = generics.bound_vars_subst(db, DebruijnIndex::INNERMOST);
         let explicitly_unsized_tys = ctx.unsized_types.into_inner();
         if let Some(implicitly_sized_predicates) =
             implicitly_sized_clauses(db, def, &explicitly_unsized_tys, &subst, &resolver)
@@ -1995,47 +1987,6 @@ fn type_for_type_alias(db: &dyn HirDatabase, t: TypeAliasId) -> Binders<Ty> {
     }
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-pub enum CallableDefId {
-    FunctionId(FunctionId),
-    StructId(StructId),
-    EnumVariantId(EnumVariantId),
-}
-
-impl InternValueTrivial for CallableDefId {}
-
-impl_from!(FunctionId, StructId, EnumVariantId for CallableDefId);
-impl From<CallableDefId> for ModuleDefId {
-    fn from(def: CallableDefId) -> ModuleDefId {
-        match def {
-            CallableDefId::FunctionId(f) => ModuleDefId::FunctionId(f),
-            CallableDefId::StructId(s) => ModuleDefId::AdtId(AdtId::StructId(s)),
-            CallableDefId::EnumVariantId(e) => ModuleDefId::EnumVariantId(e),
-        }
-    }
-}
-
-impl CallableDefId {
-    pub fn krate(self, db: &dyn HirDatabase) -> CrateId {
-        let db = db.upcast();
-        match self {
-            CallableDefId::FunctionId(f) => f.krate(db),
-            CallableDefId::StructId(s) => s.krate(db),
-            CallableDefId::EnumVariantId(e) => e.krate(db),
-        }
-    }
-}
-
-impl From<CallableDefId> for GenericDefId {
-    fn from(def: CallableDefId) -> GenericDefId {
-        match def {
-            CallableDefId::FunctionId(f) => f.into(),
-            CallableDefId::StructId(s) => s.into(),
-            CallableDefId::EnumVariantId(e) => e.into(),
-        }
-    }
-}
-
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum TyDefId {
     BuiltinType(BuiltinType),
@@ -2056,12 +2007,12 @@ pub enum ValueTyDefId {
 impl_from!(FunctionId, StructId, UnionId, EnumVariantId, ConstId, StaticId for ValueTyDefId);
 
 impl ValueTyDefId {
-    pub(crate) fn to_generic_def_id(self) -> Option<GenericDefId> {
+    pub(crate) fn to_generic_def_id(self, db: &dyn HirDatabase) -> Option<GenericDefId> {
         match self {
             Self::FunctionId(id) => Some(id.into()),
             Self::StructId(id) => Some(id.into()),
             Self::UnionId(id) => Some(id.into()),
-            Self::EnumVariantId(var) => Some(var.into()),
+            Self::EnumVariantId(var) => Some(var.lookup(db.upcast()).parent.into()),
             Self::ConstId(id) => Some(id.into()),
             Self::StaticId(_) => None,
         }
@@ -2112,7 +2063,7 @@ pub(crate) fn impl_self_ty_query(db: &dyn HirDatabase, impl_id: ImplId) -> Binde
 // returns None if def is a type arg
 pub(crate) fn const_param_ty_query(db: &dyn HirDatabase, def: ConstParamId) -> Ty {
     let parent_data = db.generic_params(def.parent());
-    let data = &parent_data.type_or_consts[def.local_id()];
+    let data = &parent_data[def.local_id()];
     let resolver = def.parent().resolver(db.upcast());
     let ctx = TyLoweringContext::new(db, &resolver, def.parent().into());
     match data {

crates/hir-ty/src/method_resolution.rs

@@ -127,9 +127,11 @@ pub(crate) const ALL_INT_FPS: [TyFingerprint; 12] = [
     TyFingerprint::Scalar(Scalar::Uint(UintTy::Usize)),
 ];
 
-pub(crate) const ALL_FLOAT_FPS: [TyFingerprint; 2] = [
+pub(crate) const ALL_FLOAT_FPS: [TyFingerprint; 4] = [
+    TyFingerprint::Scalar(Scalar::Float(FloatTy::F16)),
     TyFingerprint::Scalar(Scalar::Float(FloatTy::F32)),
     TyFingerprint::Scalar(Scalar::Float(FloatTy::F64)),
+    TyFingerprint::Scalar(Scalar::Float(FloatTy::F128)),
 ];
 
 type TraitFpMap = FxHashMap<TraitId, FxHashMap<Option<TyFingerprint>, Box<[ImplId]>>>;
@@ -1322,7 +1324,7 @@ fn iterate_inherent_methods(
         callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId, bool) -> ControlFlow<()>,
     ) -> ControlFlow<()> {
         for &impl_id in impls.for_self_ty(self_ty) {
-            for &item in &table.db.impl_data(impl_id).items {
+            for &item in table.db.impl_data(impl_id).items.iter() {
                 let visible = match is_valid_impl_method_candidate(
                     table,
                     self_ty,

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

@@ -18,6 +18,10 @@ use hir_expand::{mod_path::ModPath, HirFileIdExt, InFile};
 use intern::Interned;
 use la_arena::ArenaMap;
 use rustc_abi::TargetDataLayout;
+use rustc_apfloat::{
+    ieee::{Half as f16, Quad as f128},
+    Float,
+};
 use rustc_hash::{FxHashMap, FxHashSet};
 use stdx::never;
 use syntax::{SyntaxNodePtr, TextRange};
@@ -55,6 +59,13 @@ macro_rules! from_bytes {
             Err(_) => return Err(MirEvalError::InternalError(stringify!(mismatched size in constructing $ty).into())),
         }))
     };
+    ($apfloat:tt, $bits:tt, $value:expr) => {
+        // FIXME(#17451): Switch to builtin `f16` and `f128` once they are stable.
+        $apfloat::from_bits($bits::from_le_bytes(match ($value).try_into() {
+            Ok(it) => it,
+            Err(_) => return Err(MirEvalError::InternalError(stringify!(mismatched size in constructing $apfloat).into())),
+        }).into())
+    };
 }
 
 macro_rules! not_supported {
@@ -1110,6 +1121,10 @@ impl Evaluator<'_> {
                 }
                 if let TyKind::Scalar(chalk_ir::Scalar::Float(f)) = ty.kind(Interner) {
                     match f {
+                        chalk_ir::FloatTy::F16 => {
+                            let c = -from_bytes!(f16, u16, c);
+                            Owned(u16::try_from(c.to_bits()).unwrap().to_le_bytes().into())
+                        }
                         chalk_ir::FloatTy::F32 => {
                             let c = -from_bytes!(f32, c);
                             Owned(c.to_le_bytes().into())
@@ -1118,6 +1133,10 @@ impl Evaluator<'_> {
                             let c = -from_bytes!(f64, c);
                             Owned(c.to_le_bytes().into())
                         }
+                        chalk_ir::FloatTy::F128 => {
+                            let c = -from_bytes!(f128, u128, c);
+                            Owned(c.to_bits().to_le_bytes().into())
+                        }
                     }
                 } else {
                     let mut c = c.to_vec();
@@ -1169,6 +1188,39 @@ impl Evaluator<'_> {
                 }
                 if let TyKind::Scalar(chalk_ir::Scalar::Float(f)) = ty.kind(Interner) {
                     match f {
+                        chalk_ir::FloatTy::F16 => {
+                            let l = from_bytes!(f16, u16, lc);
+                            let r = from_bytes!(f16, u16, rc);
+                            match op {
+                                BinOp::Ge
+                                | BinOp::Gt
+                                | BinOp::Le
+                                | BinOp::Lt
+                                | BinOp::Eq
+                                | BinOp::Ne => {
+                                    let r = op.run_compare(l, r) as u8;
+                                    Owned(vec![r])
+                                }
+                                BinOp::Add | BinOp::Sub | BinOp::Mul | BinOp::Div => {
+                                    let r = match op {
+                                        BinOp::Add => l + r,
+                                        BinOp::Sub => l - r,
+                                        BinOp::Mul => l * r,
+                                        BinOp::Div => l / r,
+                                        _ => unreachable!(),
+                                    };
+                                    Owned(
+                                        u16::try_from(r.value.to_bits())
+                                            .unwrap()
+                                            .to_le_bytes()
+                                            .into(),
+                                    )
+                                }
+                                it => not_supported!(
+                                    "invalid binop {it:?} on floating point operators"
+                                ),
+                            }
+                        }
                         chalk_ir::FloatTy::F32 => {
                             let l = from_bytes!(f32, lc);
                             let r = from_bytes!(f32, rc);
@@ -1225,6 +1277,34 @@ impl Evaluator<'_> {
                                 ),
                             }
                         }
+                        chalk_ir::FloatTy::F128 => {
+                            let l = from_bytes!(f128, u128, lc);
+                            let r = from_bytes!(f128, u128, rc);
+                            match op {
+                                BinOp::Ge
+                                | BinOp::Gt
+                                | BinOp::Le
+                                | BinOp::Lt
+                                | BinOp::Eq
+                                | BinOp::Ne => {
+                                    let r = op.run_compare(l, r) as u8;
+                                    Owned(vec![r])
+                                }
+                                BinOp::Add | BinOp::Sub | BinOp::Mul | BinOp::Div => {
+                                    let r = match op {
+                                        BinOp::Add => l + r,
+                                        BinOp::Sub => l - r,
+                                        BinOp::Mul => l * r,
+                                        BinOp::Div => l / r,
+                                        _ => unreachable!(),
+                                    };
+                                    Owned(r.value.to_bits().to_le_bytes().into())
+                                }
+                                it => not_supported!(
+                                    "invalid binop {it:?} on floating point operators"
+                                ),
+                            }
+                        }
                     }
                 } else {
                     let is_signed = matches!(ty.as_builtin(), Some(BuiltinType::Int(_)));

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

@@ -627,6 +627,7 @@ impl Evaluator<'_> {
         if let Some(name) = name.strip_prefix("atomic_") {
             return self.exec_atomic_intrinsic(name, args, generic_args, destination, locals, span);
         }
+        // FIXME(#17451): Add `f16` and `f128` intrinsics.
         if let Some(name) = name.strip_suffix("f64") {
             let result = match name {
                 "sqrt" | "sin" | "cos" | "exp" | "exp2" | "log" | "log10" | "log2" | "fabs"

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

@@ -19,6 +19,7 @@ use hir_def::{
 };
 use hir_expand::name::Name;
 use la_arena::ArenaMap;
+use rustc_apfloat::Float;
 use rustc_hash::FxHashMap;
 use syntax::TextRange;
 use triomphe::Arc;
@@ -183,7 +184,7 @@ impl MirLowerError {
             },
             MirLowerError::GenericArgNotProvided(id, subst) => {
                 let parent = id.parent;
-                let param = &db.generic_params(parent).type_or_consts[id.local_id];
+                let param = &db.generic_params(parent)[id.local_id];
                 writeln!(
                     f,
                     "Generic arg not provided for {}",
@@ -483,7 +484,7 @@ impl<'ctx> MirLowerCtx<'ctx> {
                         Ok(Some(current))
                     }
                     ValueNs::GenericParam(p) => {
-                        let Some(def) = self.owner.as_generic_def_id() else {
+                        let Some(def) = self.owner.as_generic_def_id(self.db.upcast()) else {
                             not_supported!("owner without generic def id");
                         };
                         let gen = generics(self.db.upcast(), def);
@@ -1330,7 +1331,7 @@ impl<'ctx> MirLowerCtx<'ctx> {
     }
 
     fn placeholder_subst(&mut self) -> Substitution {
-        match self.owner.as_generic_def_id() {
+        match self.owner.as_generic_def_id(self.db.upcast()) {
             Some(it) => TyBuilder::placeholder_subst(self.db, it),
             None => Substitution::empty(Interner),
         }
@@ -1432,10 +1433,14 @@ impl<'ctx> MirLowerCtx<'ctx> {
             hir_def::hir::Literal::Int(it, _) => Box::from(&it.to_le_bytes()[0..size()?]),
             hir_def::hir::Literal::Uint(it, _) => Box::from(&it.to_le_bytes()[0..size()?]),
             hir_def::hir::Literal::Float(f, _) => match size()? {
-                8 => Box::new(f.into_f64().to_le_bytes()),
+                16 => Box::new(f.to_f128().to_bits().to_le_bytes()),
-                4 => Box::new(f.into_f32().to_le_bytes()),
+                8 => Box::new(f.to_f64().to_le_bytes()),
+                4 => Box::new(f.to_f32().to_le_bytes()),
+                2 => Box::new(u16::try_from(f.to_f16().to_bits()).unwrap().to_le_bytes()),
                 _ => {
-                    return Err(MirLowerError::TypeError("float with size other than 4 or 8 bytes"))
+                    return Err(MirLowerError::TypeError(
+                        "float with size other than 2, 4, 8 or 16 bytes",
+                    ))
                 }
             },
         };
@@ -2160,9 +2165,7 @@ pub fn lower_to_mir(
     root_expr: ExprId,
 ) -> Result<MirBody> {
     if infer.has_errors {
-        return Err(MirLowerError::TypeMismatch(
+        return Err(MirLowerError::TypeMismatch(None));
-            infer.type_mismatches().next().map(|(_, it)| it.clone()),
-        ));
     }
     let mut ctx = MirLowerCtx::new(db, owner, body, infer);
     // 0 is return local

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

@@ -302,7 +302,7 @@ pub fn monomorphized_mir_body_query(
     subst: Substitution,
     trait_env: Arc<crate::TraitEnvironment>,
 ) -> Result<Arc<MirBody>, MirLowerError> {
-    let generics = owner.as_generic_def_id().map(|g_def| generics(db.upcast(), g_def));
+    let generics = owner.as_generic_def_id(db.upcast()).map(|g_def| generics(db.upcast(), g_def));
     let filler = &mut Filler { db, subst: &subst, trait_env, generics, owner };
     let body = db.mir_body(owner)?;
     let mut body = (*body).clone();
@@ -327,7 +327,7 @@ pub fn monomorphized_mir_body_for_closure_query(
     trait_env: Arc<crate::TraitEnvironment>,
 ) -> Result<Arc<MirBody>, MirLowerError> {
     let InternedClosure(owner, _) = db.lookup_intern_closure(closure.into());
-    let generics = owner.as_generic_def_id().map(|g_def| generics(db.upcast(), g_def));
+    let generics = owner.as_generic_def_id(db.upcast()).map(|g_def| generics(db.upcast(), g_def));
     let filler = &mut Filler { db, subst: &subst, trait_env, generics, owner };
     let body = db.mir_body_for_closure(closure)?;
     let mut body = (*body).clone();
@@ -343,7 +343,7 @@ pub fn monomorphize_mir_body_bad(
     trait_env: Arc<crate::TraitEnvironment>,
 ) -> Result<MirBody, MirLowerError> {
     let owner = body.owner;
-    let generics = owner.as_generic_def_id().map(|g_def| generics(db.upcast(), g_def));
+    let generics = owner.as_generic_def_id(db.upcast()).map(|g_def| generics(db.upcast(), g_def));
     let filler = &mut Filler { db, subst: &subst, trait_env, generics, owner };
     filler.fill_body(&mut body)?;
     Ok(body)

crates/hir-ty/src/primitive.rs

@@ -27,8 +27,10 @@ pub fn uint_ty_to_string(ty: UintTy) -> &'static str {
 
 pub fn float_ty_to_string(ty: FloatTy) -> &'static str {
     match ty {
+        FloatTy::F16 => "f16",
         FloatTy::F32 => "f32",
         FloatTy::F64 => "f64",
+        FloatTy::F128 => "f128",
     }
 }
 
@@ -56,7 +58,9 @@ pub(super) fn uint_ty_from_builtin(t: BuiltinUint) -> UintTy {
 
 pub(super) fn float_ty_from_builtin(t: BuiltinFloat) -> FloatTy {
     match t {
+        BuiltinFloat::F16 => FloatTy::F16,
         BuiltinFloat::F32 => FloatTy::F32,
         BuiltinFloat::F64 => FloatTy::F64,
+        BuiltinFloat::F128 => FloatTy::F128,
     }
 }

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

@@ -111,8 +111,10 @@ fn infer_literal_pattern() {
             if let "foo" = any() {}
             if let 1 = any() {}
             if let 1u32 = any() {}
+            if let 1f16 = any() {}
             if let 1f32 = any() {}
             if let 1.0 = any() {}
+            if let 1f128 = any() {}
             if let true = any() {}
         }
         "#,
@@ -121,7 +123,7 @@ fn infer_literal_pattern() {
             19..26 'loop {}': !
             24..26 '{}': ()
             37..38 'x': &'? i32
-            46..208 '{     ...) {} }': ()
+            46..263 '{     ...) {} }': ()
             52..75 'if let...y() {}': ()
             55..72 'let "f... any()': bool
             59..64 '"foo"': &'static str
@@ -145,25 +147,39 @@ fn infer_literal_pattern() {
             124..126 '{}': ()
             131..153 'if let...y() {}': ()
             134..150 'let 1f... any()': bool
-            138..142 '1f32': f32
+            138..142 '1f16': f16
-            138..142 '1f32': f32
+            138..142 '1f16': f16
-            145..148 'any': fn any<f32>() -> f32
+            145..148 'any': fn any<f16>() -> f16
-            145..150 'any()': f32
+            145..150 'any()': f16
             151..153 '{}': ()
-            158..179 'if let...y() {}': ()
+            158..180 'if let...y() {}': ()
-            161..176 'let 1.0 = any()': bool
+            161..177 'let 1f... any()': bool
-            165..168 '1.0': f64
+            165..169 '1f32': f32
-            165..168 '1.0': f64
+            165..169 '1f32': f32
-            171..174 'any': fn any<f64>() -> f64
+            172..175 'any': fn any<f32>() -> f32
-            171..176 'any()': f64
+            172..177 'any()': f32
-            177..179 '{}': ()
+            178..180 '{}': ()
-            184..206 'if let...y() {}': ()
+            185..206 'if let...y() {}': ()
-            187..203 'let tr... any()': bool
+            188..203 'let 1.0 = any()': bool
-            191..195 'true': bool
+            192..195 '1.0': f64
-            191..195 'true': bool
+            192..195 '1.0': f64
-            198..201 'any': fn any<bool>() -> bool
+            198..201 'any': fn any<f64>() -> f64
-            198..203 'any()': bool
+            198..203 'any()': f64
             204..206 '{}': ()
+            211..234 'if let...y() {}': ()
+            214..231 'let 1f... any()': bool
+            218..223 '1f128': f128
+            218..223 '1f128': f128
+            226..229 'any': fn any<f128>() -> f128
+            226..231 'any()': f128
+            232..234 '{}': ()
+            239..261 'if let...y() {}': ()
+            242..258 'let tr... any()': bool
+            246..250 'true': bool
+            246..250 'true': bool
+            253..256 'any': fn any<bool>() -> bool
+            253..258 'any()': bool
+            259..261 '{}': ()
         "#]],
     );
 }

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

@@ -1999,3 +1999,45 @@ where
 "#,
     );
 }
+
+#[test]
+fn tait_async_stack_overflow_17199() {
+    check_types(
+        r#"
+    //- minicore: fmt, future
+    type Foo = impl core::fmt::Debug;
+
+    async fn foo() -> Foo {
+        ()
+    }
+
+    async fn test() {
+        let t = foo().await;
+         // ^ impl Debug
+    }
+"#,
+    );
+}
+
+#[test]
+fn lifetime_params_move_param_defaults() {
+    check_types(
+        r#"
+pub struct Thing<'s, T = u32>;
+
+impl <'s> Thing<'s> {
+    pub fn new() -> Thing<'s> {
+        Thing
+      //^^^^^ Thing<'?, u32>
+    }
+}
+
+fn main() {
+    let scope =
+      //^^^^^ &'? Thing<'?, u32>
+                &Thing::new();
+               //^^^^^^^^^^^^ Thing<'?, u32>
+}
+"#,
+    );
+}

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

@@ -397,8 +397,10 @@ fn infer_literals() {
         r##"
         fn test() {
             5i32;
+            5f16;
             5f32;
             5f64;
+            5f128;
             "hello";
             b"bytes";
             'c';
@@ -421,26 +423,28 @@ h";
         }
         "##,
         expect![[r##"
-            18..478 '{     ...     }': ()
+            18..515 '{     ...     }': ()
             32..36 '5i32': i32
-            50..54 '5f32': f32
+            50..54 '5f16': f16
-            68..72 '5f64': f64
+            68..72 '5f32': f32
-            86..93 '"hello"': &'static str
+            86..90 '5f64': f64
-            107..115 'b"bytes"': &'static [u8; 5]
+            104..109 '5f128': f128
-            129..132 ''c'': char
+            123..130 '"hello"': &'static str
-            146..150 'b'b'': u8
+            144..152 'b"bytes"': &'static [u8; 5]
-            164..168 '3.14': f64
+            166..169 ''c'': char
-            182..186 '5000': i32
+            183..187 'b'b'': u8
-            200..205 'false': bool
+            201..205 '3.14': f64
-            219..223 'true': bool
+            219..223 '5000': i32
-            237..333 'r#"   ...    "#': &'static str
+            237..242 'false': bool
-            347..357 'br#"yolo"#': &'static [u8; 4]
+            256..260 'true': bool
-            375..376 'a': &'static [u8; 4]
+            274..370 'r#"   ...    "#': &'static str
-            379..403 'b"a\x2...    c"': &'static [u8; 4]
+            384..394 'br#"yolo"#': &'static [u8; 4]
-            421..422 'b': &'static [u8; 4]
+            412..413 'a': &'static [u8; 4]
-            425..433 'br"g\ h"': &'static [u8; 4]
+            416..440 'b"a\x2...    c"': &'static [u8; 4]
-            451..452 'c': &'static [u8; 6]
+            458..459 'b': &'static [u8; 4]
-            455..467 'br#"x"\"yb"#': &'static [u8; 6]
+            462..470 'br"g\ h"': &'static [u8; 4]
+            488..489 'c': &'static [u8; 6]
+            492..504 'br#"x"\"yb"#': &'static [u8; 6]
         "##]],
     );
 }

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

@@ -4824,3 +4824,76 @@ fn foo() {
 "#,
     )
 }
+
+#[test]
+fn nested_impl_traits() {
+    check_infer(
+        r#"
+//- minicore: fn
+trait Foo {}
+
+trait Bar<T> {}
+
+trait Baz {
+    type Assoc;
+}
+
+struct Qux<T> {
+    qux: T,
+}
+
+struct S;
+
+impl Foo for S {}
+
+fn not_allowed1(f: impl Fn(impl Foo)) {
+    let foo = S;
+    f(foo);
+}
+
+// This caused stack overflow in #17498
+fn not_allowed2(f: impl Fn(&impl Foo)) {
+    let foo = S;
+    f(&foo);
+}
+
+fn not_allowed3(bar: impl Bar<impl Foo>) {}
+
+// This also caused stack overflow
+fn not_allowed4(bar: impl Bar<&impl Foo>) {}
+
+fn allowed1(baz: impl Baz<Assoc = impl Foo>) {}
+
+fn allowed2<'a>(baz: impl Baz<Assoc = &'a (impl Foo + 'a)>) {}
+
+fn allowed3(baz: impl Baz<Assoc = Qux<impl Foo>>) {}
+"#,
+        expect![[r#"
+            139..140 'f': impl Fn({unknown}) + ?Sized
+            161..193 '{     ...oo); }': ()
+            171..174 'foo': S
+            177..178 'S': S
+            184..185 'f': impl Fn({unknown}) + ?Sized
+            184..190 'f(foo)': ()
+            186..189 'foo': S
+            251..252 'f': impl Fn(&'? {unknown}) + ?Sized
+            274..307 '{     ...oo); }': ()
+            284..287 'foo': S
+            290..291 'S': S
+            297..298 'f': impl Fn(&'? {unknown}) + ?Sized
+            297..304 'f(&foo)': ()
+            299..303 '&foo': &'? S
+            300..303 'foo': S
+            325..328 'bar': impl Bar<{unknown}> + ?Sized
+            350..352 '{}': ()
+            405..408 'bar': impl Bar<&'? {unknown}> + ?Sized
+            431..433 '{}': ()
+            447..450 'baz': impl Baz<Assoc = impl Foo + ?Sized> + ?Sized
+            480..482 '{}': ()
+            500..503 'baz': impl Baz<Assoc = &'a impl Foo + 'a + ?Sized> + ?Sized
+            544..546 '{}': ()
+            560..563 'baz': impl Baz<Assoc = Qux<impl Foo + ?Sized>> + ?Sized
+            598..600 '{}': ()
+        "#]],
+    )
+}

crates/hir-ty/src/utils.rs

@@ -157,8 +157,7 @@ fn direct_super_traits(db: &dyn DefDatabase, trait_: TraitId, cb: impl FnMut(Tra
     let generic_params = db.generic_params(trait_.into());
     let trait_self = generic_params.trait_self_param();
     generic_params
-        .where_predicates
+        .where_predicates()
-        .iter()
         .filter_map(|pred| match pred {
             WherePredicate::ForLifetime { target, bound, .. }
             | WherePredicate::TypeBound { target, bound } => {

crates/hir/src/display.rs

@@ -452,7 +452,7 @@ impl HirDisplay for TypeOrConstParam {
 impl HirDisplay for TypeParam {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
         let params = f.db.generic_params(self.id.parent());
-        let param_data = &params.type_or_consts[self.id.local_id()];
+        let param_data = &params[self.id.local_id()];
         let substs = TyBuilder::placeholder_subst(f.db, self.id.parent());
         let krate = self.id.parent().krate(f.db).id;
         let ty =
@@ -539,11 +539,10 @@ fn write_generic_params(
     f: &mut HirFormatter<'_>,
 ) -> Result<(), HirDisplayError> {
     let params = f.db.generic_params(def);
-    if params.lifetimes.is_empty()
+    if params.iter_lt().next().is_none()
-        && params.type_or_consts.iter().all(|it| it.1.const_param().is_none())
+        && params.iter_type_or_consts().all(|it| it.1.const_param().is_none())
         && params
-            .type_or_consts
+            .iter_type_or_consts()
-            .iter()
             .filter_map(|it| it.1.type_param())
             .all(|param| !matches!(param.provenance, TypeParamProvenance::TypeParamList))
     {
@@ -560,11 +559,11 @@ fn write_generic_params(
             f.write_str(", ")
         }
     };
-    for (_, lifetime) in params.lifetimes.iter() {
+    for (_, lifetime) in params.iter_lt() {
         delim(f)?;
         write!(f, "{}", lifetime.name.display(f.db.upcast()))?;
     }
-    for (_, ty) in params.type_or_consts.iter() {
+    for (_, ty) in params.iter_type_or_consts() {
         if let Some(name) = &ty.name() {
             match ty {
                 TypeOrConstParamData::TypeParamData(ty) => {
@@ -612,11 +611,11 @@ fn write_where_clause(
 }
 
 fn has_disaplayable_predicates(params: &Interned<GenericParams>) -> bool {
-    params.where_predicates.iter().any(|pred| {
+    params.where_predicates().any(|pred| {
         !matches!(
             pred,
             WherePredicate::TypeBound { target: WherePredicateTypeTarget::TypeOrConstParam(id), .. }
-            if params.type_or_consts[*id].name().is_none()
+            if params[*id].name().is_none()
         )
     })
 }
@@ -631,13 +630,13 @@ fn write_where_predicates(
     let is_unnamed_type_target =
         |params: &Interned<GenericParams>, target: &WherePredicateTypeTarget| {
             matches!(target,
-                WherePredicateTypeTarget::TypeOrConstParam(id) if params.type_or_consts[*id].name().is_none()
+                WherePredicateTypeTarget::TypeOrConstParam(id) if params[*id].name().is_none()
             )
         };
 
     let write_target = |target: &WherePredicateTypeTarget, f: &mut HirFormatter<'_>| match target {
         WherePredicateTypeTarget::TypeRef(ty) => ty.hir_fmt(f),
-        WherePredicateTypeTarget::TypeOrConstParam(id) => match params.type_or_consts[*id].name() {
+        WherePredicateTypeTarget::TypeOrConstParam(id) => match params[*id].name() {
             Some(name) => write!(f, "{}", name.display(f.db.upcast())),
             None => f.write_str("{unnamed}"),
         },
@@ -653,7 +652,7 @@ fn write_where_predicates(
         _ => false,
     };
 
-    let mut iter = params.where_predicates.iter().peekable();
+    let mut iter = params.where_predicates().peekable();
     while let Some(pred) = iter.next() {
         if matches!(pred, TypeBound { target, .. } if is_unnamed_type_target(params, target)) {
             continue;

crates/hir/src/from_id.rs

@@ -182,7 +182,6 @@ impl From<GenericDef> for GenericDefId {
             GenericDef::TraitAlias(it) => GenericDefId::TraitAliasId(it.id),
             GenericDef::TypeAlias(it) => GenericDefId::TypeAliasId(it.id),
             GenericDef::Impl(it) => GenericDefId::ImplId(it.id),
-            GenericDef::Variant(it) => GenericDefId::EnumVariantId(it.into()),
             GenericDef::Const(it) => GenericDefId::ConstId(it.id),
         }
     }
@@ -197,7 +196,6 @@ impl From<GenericDefId> for GenericDef {
             GenericDefId::TraitAliasId(it) => GenericDef::TraitAlias(it.into()),
             GenericDefId::TypeAliasId(it) => GenericDef::TypeAlias(it.into()),
             GenericDefId::ImplId(it) => GenericDef::Impl(it.into()),
-            GenericDefId::EnumVariantId(it) => GenericDef::Variant(it.into()),
             GenericDefId::ConstId(it) => GenericDef::Const(it.into()),
         }
     }

crates/hir/src/has_source.rs

@@ -5,10 +5,10 @@ use either::Either;
 use hir_def::{
     nameres::{ModuleOrigin, ModuleSource},
     src::{HasChildSource, HasSource as _},
-    Lookup, MacroId, VariantId,
+    CallableDefId, Lookup, MacroId, VariantId,
 };
 use hir_expand::{HirFileId, InFile};
-use hir_ty::{db::InternedClosure, CallableDefId};
+use hir_ty::db::InternedClosure;
 use syntax::ast;
 use tt::TextRange;
 

crates/hir/src/lib.rs

@@ -17,7 +17,6 @@
 //! from the ide with completions, hovers, etc. It is a (soft, internal) boundary:
 //! <https://www.tedinski.com/2018/02/06/system-boundaries.html>.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 #![recursion_limit = "512"]
 
@@ -52,11 +51,11 @@ use hir_def::{
     path::ImportAlias,
     per_ns::PerNs,
     resolver::{HasResolver, Resolver},
-    AssocItemId, AssocItemLoc, AttrDefId, ConstId, ConstParamId, CrateRootModuleId, DefWithBodyId,
+    AssocItemId, AssocItemLoc, AttrDefId, CallableDefId, ConstId, ConstParamId, CrateRootModuleId,
-    EnumId, EnumVariantId, ExternCrateId, FunctionId, GenericDefId, GenericParamId, HasModule,
+    DefWithBodyId, EnumId, EnumVariantId, ExternCrateId, FunctionId, GenericDefId, GenericParamId,
-    ImplId, InTypeConstId, ItemContainerId, LifetimeParamId, LocalFieldId, Lookup, MacroExpander,
+    HasModule, ImplId, InTypeConstId, ItemContainerId, LifetimeParamId, LocalFieldId, Lookup,
-    ModuleId, StaticId, StructId, TraitAliasId, TraitId, TupleId, TypeAliasId, TypeOrConstParamId,
+    MacroExpander, ModuleId, StaticId, StructId, TraitAliasId, TraitId, TupleId, TypeAliasId,
-    TypeParamId, UnionId,
+    TypeOrConstParamId, TypeParamId, UnionId,
 };
 use hir_expand::{
     attrs::collect_attrs, name::name, proc_macro::ProcMacroKind, AstId, MacroCallKind, ValueResult,
@@ -71,7 +70,7 @@ use hir_ty::{
     mir::{interpret_mir, MutBorrowKind},
     primitive::UintTy,
     traits::FnTrait,
-    AliasTy, CallableDefId, CallableSig, Canonical, CanonicalVarKinds, Cast, ClosureId, GenericArg,
+    AliasTy, CallableSig, Canonical, CanonicalVarKinds, Cast, ClosureId, GenericArg,
     GenericArgData, Interner, ParamKind, QuantifiedWhereClause, Scalar, Substitution,
     TraitEnvironment, TraitRefExt, Ty, TyBuilder, TyDefId, TyExt, TyKind, ValueTyDefId,
     WhereClause,
@@ -666,7 +665,7 @@ impl Module {
                 }
                 let parent = impl_def.id.into();
                 let generic_params = db.generic_params(parent);
-                let lifetime_params = generic_params.lifetimes.iter().map(|(local_id, _)| {
+                let lifetime_params = generic_params.iter_lt().map(|(local_id, _)| {
                     GenericParamId::LifetimeParamId(LifetimeParamId { parent, local_id })
                 });
                 let type_params = generic_params
@@ -760,7 +759,7 @@ impl Module {
                 impl_assoc_items_scratch.clear();
             }
 
-            for &item in &db.impl_data(impl_def.id).items {
+            for &item in db.impl_data(impl_def.id).items.iter() {
                 AssocItem::from(item).diagnostics(db, acc, style_lints);
             }
         }
@@ -1144,7 +1143,7 @@ impl Field {
         let generic_def_id: GenericDefId = match self.parent {
             VariantDef::Struct(it) => it.id.into(),
             VariantDef::Union(it) => it.id.into(),
-            VariantDef::Variant(it) => it.id.into(),
+            VariantDef::Variant(it) => it.id.lookup(db.upcast()).parent.into(),
         };
         let substs = TyBuilder::placeholder_subst(db, generic_def_id);
         let ty = db.field_types(var_id)[self.id].clone().substitute(Interner, &substs);
@@ -1177,7 +1176,9 @@ impl Field {
         db.layout_of_ty(
             self.ty(db).ty,
             db.trait_environment(match hir_def::VariantId::from(self.parent) {
-                hir_def::VariantId::EnumVariantId(id) => GenericDefId::EnumVariantId(id),
+                hir_def::VariantId::EnumVariantId(id) => {
+                    GenericDefId::AdtId(id.lookup(db.upcast()).parent.into())
+                }
                 hir_def::VariantId::StructId(id) => GenericDefId::AdtId(id.into()),
                 hir_def::VariantId::UnionId(id) => GenericDefId::AdtId(id.into()),
             }),
@@ -1539,8 +1540,7 @@ impl Adt {
         resolver
             .generic_params()
             .and_then(|gp| {
-                gp.lifetimes
+                gp.iter_lt()
-                    .iter()
                     // there should only be a single lifetime
                     // but `Arena` requires to use an iterator
                     .nth(0)
@@ -2501,9 +2501,8 @@ impl Trait {
         db: &dyn HirDatabase,
         count_required_only: bool,
     ) -> usize {
-        db.generic_params(GenericDefId::from(self.id))
+        db.generic_params(self.id.into())
-            .type_or_consts
+            .iter_type_or_consts()
-            .iter()
             .filter(|(_, ty)| !matches!(ty, TypeOrConstParamData::TypeParamData(ty) if ty.provenance != TypeParamProvenance::TypeParamList))
             .filter(|(_, ty)| !count_required_only || !ty.has_default())
             .count()
@@ -2623,6 +2622,13 @@ impl BuiltinType {
         matches!(self.inner, hir_def::builtin_type::BuiltinType::Float(_))
     }
 
+    pub fn is_f16(&self) -> bool {
+        matches!(
+            self.inner,
+            hir_def::builtin_type::BuiltinType::Float(hir_def::builtin_type::BuiltinFloat::F16)
+        )
+    }
+
     pub fn is_f32(&self) -> bool {
         matches!(
             self.inner,
@@ -2637,6 +2643,13 @@ impl BuiltinType {
         )
     }
 
+    pub fn is_f128(&self) -> bool {
+        matches!(
+            self.inner,
+            hir_def::builtin_type::BuiltinType::Float(hir_def::builtin_type::BuiltinFloat::F128)
+        )
+    }
+
     pub fn is_char(&self) -> bool {
         matches!(self.inner, hir_def::builtin_type::BuiltinType::Char)
     }
@@ -3107,9 +3120,6 @@ pub enum GenericDef {
     TraitAlias(TraitAlias),
     TypeAlias(TypeAlias),
     Impl(Impl),
-    // enum variants cannot have generics themselves, but their parent enums
-    // can, and this makes some code easier to write
-    Variant(Variant),
     // consts can have type parameters from their parents (i.e. associated consts of traits)
     Const(Const),
 }
@@ -3120,7 +3130,6 @@ impl_from!(
     TraitAlias,
     TypeAlias,
     Impl,
-    Variant,
     Const
     for GenericDef
 );
@@ -3128,7 +3137,7 @@ impl_from!(
 impl GenericDef {
     pub fn params(self, db: &dyn HirDatabase) -> Vec<GenericParam> {
         let generics = db.generic_params(self.into());
-        let ty_params = generics.type_or_consts.iter().map(|(local_id, _)| {
+        let ty_params = generics.iter_type_or_consts().map(|(local_id, _)| {
             let toc = TypeOrConstParam { id: TypeOrConstParamId { parent: self.into(), local_id } };
             match toc.split(db) {
                 Either::Left(it) => GenericParam::ConstParam(it),
@@ -3145,8 +3154,7 @@ impl GenericDef {
     pub fn lifetime_params(self, db: &dyn HirDatabase) -> Vec<LifetimeParam> {
         let generics = db.generic_params(self.into());
         generics
-            .lifetimes
+            .iter_lt()
-            .iter()
             .map(|(local_id, _)| LifetimeParam {
                 id: LifetimeParamId { parent: self.into(), local_id },
             })
@@ -3156,8 +3164,7 @@ impl GenericDef {
     pub fn type_or_const_params(self, db: &dyn HirDatabase) -> Vec<TypeOrConstParam> {
         let generics = db.generic_params(self.into());
         generics
-            .type_or_consts
+            .iter_type_or_consts()
-            .iter()
             .map(|(local_id, _)| TypeOrConstParam {
                 id: TypeOrConstParamId { parent: self.into(), local_id },
             })
@@ -3499,7 +3506,7 @@ impl TypeParam {
     /// argument)?
     pub fn is_implicit(self, db: &dyn HirDatabase) -> bool {
         let params = db.generic_params(self.id.parent());
-        let data = &params.type_or_consts[self.id.local_id()];
+        let data = &params[self.id.local_id()];
         match data.type_param().unwrap().provenance {
             hir_def::generics::TypeParamProvenance::TypeParamList => false,
             hir_def::generics::TypeParamProvenance::TraitSelf
@@ -3553,7 +3560,7 @@ pub struct LifetimeParam {
 impl LifetimeParam {
     pub fn name(self, db: &dyn HirDatabase) -> Name {
         let params = db.generic_params(self.id.parent);
-        params.lifetimes[self.id.local_id].name.clone()
+        params[self.id.local_id].name.clone()
     }
 
     pub fn module(self, db: &dyn HirDatabase) -> Module {
@@ -3577,7 +3584,7 @@ impl ConstParam {
 
     pub fn name(self, db: &dyn HirDatabase) -> Name {
         let params = db.generic_params(self.id.parent());
-        match params.type_or_consts[self.id.local_id()].name() {
+        match params[self.id.local_id()].name() {
             Some(it) => it.clone(),
             None => {
                 never!();
@@ -3605,9 +3612,9 @@ impl ConstParam {
 }
 
 fn generic_arg_from_param(db: &dyn HirDatabase, id: TypeOrConstParamId) -> Option<GenericArg> {
-    let params = db.generic_defaults(id.parent);
     let local_idx = hir_ty::param_idx(db, id)?;
-    let ty = params.get(local_idx)?.clone();
+    let defaults = db.generic_defaults(id.parent);
+    let ty = defaults.get(local_idx)?.clone();
     let subst = TyBuilder::placeholder_subst(db, id.parent);
     Some(ty.substitute(Interner, &subst))
 }
@@ -3620,7 +3627,7 @@ pub struct TypeOrConstParam {
 impl TypeOrConstParam {
     pub fn name(self, db: &dyn HirDatabase) -> Name {
         let params = db.generic_params(self.id.parent);
-        match params.type_or_consts[self.id.local_id].name() {
+        match params[self.id.local_id].name() {
             Some(n) => n.clone(),
             _ => Name::missing(),
         }
@@ -3636,7 +3643,7 @@ impl TypeOrConstParam {
 
     pub fn split(self, db: &dyn HirDatabase) -> Either<ConstParam, TypeParam> {
         let params = db.generic_params(self.id.parent);
-        match &params.type_or_consts[self.id.local_id] {
+        match &params[self.id.local_id] {
             hir_def::generics::TypeOrConstParamData::TypeParamData(_) => {
                 Either::Right(TypeParam { id: TypeParamId::from_unchecked(self.id) })
             }
@@ -3655,7 +3662,7 @@ impl TypeOrConstParam {
 
     pub fn as_type_param(self, db: &dyn HirDatabase) -> Option<TypeParam> {
         let params = db.generic_params(self.id.parent);
-        match &params.type_or_consts[self.id.local_id] {
+        match &params[self.id.local_id] {
             hir_def::generics::TypeOrConstParamData::TypeParamData(_) => {
                 Some(TypeParam { id: TypeParamId::from_unchecked(self.id) })
             }
@@ -3665,7 +3672,7 @@ impl TypeOrConstParam {
 
     pub fn as_const_param(self, db: &dyn HirDatabase) -> Option<ConstParam> {
         let params = db.generic_params(self.id.parent);
-        match &params.type_or_consts[self.id.local_id] {
+        match &params[self.id.local_id] {
             hir_def::generics::TypeOrConstParamData::TypeParamData(_) => None,
             hir_def::generics::TypeOrConstParamData::ConstParamData(_) => {
                 Some(ConstParam { id: ConstParamId::from_unchecked(self.id) })
@@ -4052,7 +4059,9 @@ impl Type {
                 ValueTyDefId::FunctionId(it) => GenericDefId::FunctionId(it),
                 ValueTyDefId::StructId(it) => GenericDefId::AdtId(AdtId::StructId(it)),
                 ValueTyDefId::UnionId(it) => GenericDefId::AdtId(AdtId::UnionId(it)),
-                ValueTyDefId::EnumVariantId(it) => GenericDefId::EnumVariantId(it),
+                ValueTyDefId::EnumVariantId(it) => {
+                    GenericDefId::AdtId(AdtId::EnumId(it.lookup(db.upcast()).parent))
+                }
                 ValueTyDefId::StaticId(_) => return Type::new(db, def, ty.skip_binders().clone()),
             },
         );

crates/hir/src/source_analyzer.rs

@@ -68,38 +68,44 @@ impl SourceAnalyzer {
     pub(crate) fn new_for_body(
         db: &dyn HirDatabase,
         def: DefWithBodyId,
-        node @ InFile { file_id, .. }: InFile<&SyntaxNode>,
+        node: InFile<&SyntaxNode>,
         offset: Option<TextSize>,
     ) -> SourceAnalyzer {
-        let (body, source_map) = db.body_with_source_map(def);
+        Self::new_for_body_(db, def, node, offset, Some(db.infer(def)))
-        let scopes = db.expr_scopes(def);
-        let scope = match offset {
-            None => scope_for(&scopes, &source_map, node),
-            Some(offset) => scope_for_offset(db, &scopes, &source_map, node.file_id, offset),
-        };
-        let resolver = resolver_for_scope(db.upcast(), def, scope);
-        SourceAnalyzer {
-            resolver,
-            def: Some((def, body, source_map)),
-            infer: Some(db.infer(def)),
-            file_id,
-        }
     }
 
     pub(crate) fn new_for_body_no_infer(
+        db: &dyn HirDatabase,
+        def: DefWithBodyId,
+        node: InFile<&SyntaxNode>,
+        offset: Option<TextSize>,
+    ) -> SourceAnalyzer {
+        Self::new_for_body_(db, def, node, offset, None)
+    }
+
+    pub(crate) fn new_for_body_(
         db: &dyn HirDatabase,
         def: DefWithBodyId,
         node @ InFile { file_id, .. }: InFile<&SyntaxNode>,
         offset: Option<TextSize>,
+        infer: Option<Arc<InferenceResult>>,
     ) -> SourceAnalyzer {
         let (body, source_map) = db.body_with_source_map(def);
         let scopes = db.expr_scopes(def);
         let scope = match offset {
-            None => scope_for(&scopes, &source_map, node),
+            None => scope_for(db, &scopes, &source_map, node),
-            Some(offset) => scope_for_offset(db, &scopes, &source_map, node.file_id, offset),
+            Some(offset) => {
+                debug_assert!(
+                    node.text_range().contains_inclusive(offset),
+                    "{:?} not in {:?}",
+                    offset,
+                    node.text_range()
+                );
+                scope_for_offset(db, &scopes, &source_map, node.file_id, offset)
+            }
         };
         let resolver = resolver_for_scope(db.upcast(), def, scope);
-        SourceAnalyzer { resolver, def: Some((def, body, source_map)), infer: None, file_id }
+        SourceAnalyzer { resolver, def: Some((def, body, source_map)), infer, file_id }
     }
 
     pub(crate) fn new_for_resolver(
@@ -662,7 +668,6 @@ impl SourceAnalyzer {
             return resolved;
         }
 
-        // This must be a normal source file rather than macro file.
         let ctx = LowerCtx::new(db.upcast(), self.file_id);
         let hir_path = Path::from_src(&ctx, path.clone())?;
 
@@ -955,14 +960,15 @@ impl SourceAnalyzer {
 }
 
 fn scope_for(
+    db: &dyn HirDatabase,
     scopes: &ExprScopes,
     source_map: &BodySourceMap,
     node: InFile<&SyntaxNode>,
 ) -> Option<ScopeId> {
-    node.value
+    node.ancestors_with_macros(db.upcast())
-        .ancestors()
+        .take_while(|it| !ast::Item::can_cast(it.kind()) || ast::MacroCall::can_cast(it.kind()))
-        .filter_map(ast::Expr::cast)
+        .filter_map(|it| it.map(ast::Expr::cast).transpose())
-        .filter_map(|it| source_map.node_expr(InFile::new(node.file_id, &it)))
+        .filter_map(|it| source_map.node_expr(it.as_ref()))
         .find_map(|it| scopes.scope_for(it))
 }
 
@@ -988,8 +994,8 @@ fn scope_for_offset(
                     Some(it.file_id.macro_file()?.call_node(db.upcast()))
                 })
                 .find(|it| it.file_id == from_file)
-                .filter(|it| it.value.kind() == SyntaxKind::MACRO_CALL)?;
+                .filter(|it| it.kind() == SyntaxKind::MACRO_CALL)?;
-            Some((source.value.text_range(), scope))
+            Some((source.text_range(), scope))
         })
         .filter(|(expr_range, _scope)| expr_range.start() <= offset && offset <= expr_range.end())
         // find containing scope

crates/hir/src/symbols.rs

@@ -231,7 +231,7 @@ impl<'a> SymbolCollector<'a> {
         let impl_data = self.db.impl_data(impl_id);
         let impl_name = Some(SmolStr::new(impl_data.self_ty.display(self.db).to_string()));
         self.with_container_name(impl_name, |s| {
-            for &assoc_item_id in &impl_data.items {
+            for &assoc_item_id in impl_data.items.iter() {
                 s.push_assoc_item(assoc_item_id)
             }
         })

crates/hir/src/term_search.rs

@@ -93,12 +93,6 @@ struct LookupTable {
     data: FxHashMap<Type, AlternativeExprs>,
     /// New types reached since last query by the `NewTypesKey`
     new_types: FxHashMap<NewTypesKey, Vec<Type>>,
-    /// ScopeDefs that are not interesting any more
-    exhausted_scopedefs: FxHashSet<ScopeDef>,
-    /// ScopeDefs that were used in current round
-    round_scopedef_hits: FxHashSet<ScopeDef>,
-    /// Amount of rounds since scopedef was first used.
-    rounds_since_sopedef_hit: FxHashMap<ScopeDef, u32>,
     /// Types queried but not present
     types_wishlist: FxHashSet<Type>,
     /// Threshold to squash trees to `Many`
@@ -212,37 +206,6 @@ impl LookupTable {
         }
     }
 
-    /// Mark `ScopeDef` as exhausted meaning it is not interesting for us any more
-    fn mark_exhausted(&mut self, def: ScopeDef) {
-        self.exhausted_scopedefs.insert(def);
-    }
-
-    /// Mark `ScopeDef` as used meaning we managed to produce something useful from it
-    fn mark_fulfilled(&mut self, def: ScopeDef) {
-        self.round_scopedef_hits.insert(def);
-    }
-
-    /// Start new round (meant to be called at the beginning of iteration in `term_search`)
-    ///
-    /// This functions marks some `ScopeDef`s as exhausted if there have been
-    /// `MAX_ROUNDS_AFTER_HIT` rounds after first using a `ScopeDef`.
-    fn new_round(&mut self) {
-        for def in &self.round_scopedef_hits {
-            let hits =
-                self.rounds_since_sopedef_hit.entry(*def).and_modify(|n| *n += 1).or_insert(0);
-            const MAX_ROUNDS_AFTER_HIT: u32 = 2;
-            if *hits > MAX_ROUNDS_AFTER_HIT {
-                self.exhausted_scopedefs.insert(*def);
-            }
-        }
-        self.round_scopedef_hits.clear();
-    }
-
-    /// Get exhausted `ScopeDef`s
-    fn exhausted_scopedefs(&self) -> &FxHashSet<ScopeDef> {
-        &self.exhausted_scopedefs
-    }
-
     /// Types queried but not found
     fn types_wishlist(&mut self) -> &FxHashSet<Type> {
         &self.types_wishlist
@@ -275,7 +238,7 @@ pub struct TermSearchConfig {
 
 impl Default for TermSearchConfig {
     fn default() -> Self {
-        Self { enable_borrowcheck: true, many_alternatives_threshold: 1, fuel: 400 }
+        Self { enable_borrowcheck: true, many_alternatives_threshold: 1, fuel: 1200 }
     }
 }
 
@@ -328,19 +291,12 @@ pub fn term_search<DB: HirDatabase>(ctx: &TermSearchCtx<'_, DB>) -> Vec<Expr> {
     solutions.extend(tactics::assoc_const(ctx, &defs, &mut lookup));
 
     while should_continue() {
-        lookup.new_round();
-
         solutions.extend(tactics::data_constructor(ctx, &defs, &mut lookup, should_continue));
         solutions.extend(tactics::free_function(ctx, &defs, &mut lookup, should_continue));
         solutions.extend(tactics::impl_method(ctx, &defs, &mut lookup, should_continue));
         solutions.extend(tactics::struct_projection(ctx, &defs, &mut lookup, should_continue));
         solutions.extend(tactics::impl_static_method(ctx, &defs, &mut lookup, should_continue));
         solutions.extend(tactics::make_tuple(ctx, &defs, &mut lookup, should_continue));
-
-        // Discard not interesting `ScopeDef`s for speedup
-        for def in lookup.exhausted_scopedefs() {
-            defs.remove(def);
-        }
     }
 
     solutions.into_iter().filter(|it| !it.is_many()).unique().collect()

crates/hir/src/term_search/expr.rs

@@ -9,8 +9,8 @@ use hir_ty::{
 use itertools::Itertools;
 
 use crate::{
-    Adt, AsAssocItem, AssocItemContainer, Const, ConstParam, Field, Function, GenericDef, Local,
+    Adt, AsAssocItem, AssocItemContainer, Const, ConstParam, Field, Function, Local, ModuleDef,
-    ModuleDef, SemanticsScope, Static, Struct, StructKind, Trait, Type, Variant,
+    SemanticsScope, Static, Struct, StructKind, Trait, Type, Variant,
 };
 
 /// Helper function to get path to `ModuleDef`
@@ -35,43 +35,6 @@ fn mod_item_path_str(
         .ok_or(DisplaySourceCodeError::PathNotFound)
 }
 
-/// Helper function to get path to `Type`
-fn type_path(
-    sema_scope: &SemanticsScope<'_>,
-    ty: &Type,
-    cfg: ImportPathConfig,
-) -> Result<String, DisplaySourceCodeError> {
-    let db = sema_scope.db;
-    let m = sema_scope.module();
-
-    match ty.as_adt() {
-        Some(adt) => {
-            let ty_name = ty.display_source_code(db, m.id, true)?;
-
-            let mut path = mod_item_path(sema_scope, &ModuleDef::Adt(adt), cfg).unwrap();
-            path.pop_segment();
-            let path = path.display(db.upcast()).to_string();
-            let res = match path.is_empty() {
-                true => ty_name,
-                false => format!("{path}::{ty_name}"),
-            };
-            Ok(res)
-        }
-        None => ty.display_source_code(db, m.id, true),
-    }
-}
-
-/// Helper function to filter out generic parameters that are default
-fn non_default_generics(db: &dyn HirDatabase, def: GenericDef, generics: &[Type]) -> Vec<Type> {
-    def.type_or_const_params(db)
-        .into_iter()
-        .filter_map(|it| it.as_type_param(db))
-        .zip(generics)
-        .filter(|(tp, arg)| tp.default(db).as_ref() != Some(arg))
-        .map(|(_, arg)| arg.clone())
-        .collect()
-}
-
 /// Type tree shows how can we get from set of types to some type.
 ///
 /// Consider the following code as an example
@@ -208,20 +171,7 @@ impl Expr {
                     None => Ok(format!("{target_str}.{func_name}({args})")),
                 }
             }
-            Expr::Variant { variant, generics, params } => {
+            Expr::Variant { variant, params, .. } => {
-                let generics = non_default_generics(db, (*variant).into(), generics);
-                let generics_str = match generics.is_empty() {
-                    true => String::new(),
-                    false => {
-                        let generics = generics
-                            .iter()
-                            .map(|it| type_path(sema_scope, it, cfg))
-                            .collect::<Result<Vec<String>, DisplaySourceCodeError>>()?
-                            .into_iter()
-                            .join(", ");
-                        format!("::<{generics}>")
-                    }
-                };
                 let inner = match variant.kind(db) {
                     StructKind::Tuple => {
                         let args = params
@@ -230,7 +180,7 @@ impl Expr {
                             .collect::<Result<Vec<String>, DisplaySourceCodeError>>()?
                             .into_iter()
                             .join(", ");
-                        format!("{generics_str}({args})")
+                        format!("({args})")
                     }
                     StructKind::Record => {
                         let fields = variant.fields(db);
@@ -248,16 +198,15 @@ impl Expr {
                             .collect::<Result<Vec<String>, DisplaySourceCodeError>>()?
                             .into_iter()
                             .join(", ");
-                        format!("{generics_str}{{ {args} }}")
+                        format!("{{ {args} }}")
                     }
-                    StructKind::Unit => generics_str,
+                    StructKind::Unit => String::new(),
                 };
 
                 let prefix = mod_item_path_str(sema_scope, &ModuleDef::Variant(*variant))?;
                 Ok(format!("{prefix}{inner}"))
             }
-            Expr::Struct { strukt, generics, params } => {
+            Expr::Struct { strukt, params, .. } => {
-                let generics = non_default_generics(db, (*strukt).into(), generics);
                 let inner = match strukt.kind(db) {
                     StructKind::Tuple => {
                         let args = params
@@ -286,18 +235,7 @@ impl Expr {
                             .join(", ");
                         format!(" {{ {args} }}")
                     }
-                    StructKind::Unit => match generics.is_empty() {
+                    StructKind::Unit => String::new(),
-                        true => String::new(),
-                        false => {
-                            let generics = generics
-                                .iter()
-                                .map(|it| type_path(sema_scope, it, cfg))
-                                .collect::<Result<Vec<String>, DisplaySourceCodeError>>()?
-                                .into_iter()
-                                .join(", ");
-                            format!("::<{generics}>")
-                        }
-                    },
                 };
 
                 let prefix = mod_item_path_str(sema_scope, &ModuleDef::Adt(Adt::Struct(*strukt)))?;

crates/hir/src/term_search/tactics.rs

@@ -17,11 +17,11 @@ use itertools::Itertools;
 use rustc_hash::FxHashSet;
 
 use crate::{
-    Adt, AssocItem, Enum, GenericDef, GenericParam, HasVisibility, Impl, ModuleDef, ScopeDef, Type,
+    Adt, AssocItem, GenericDef, GenericParam, HasAttrs, HasVisibility, Impl, ModuleDef, ScopeDef,
-    TypeParam, Variant,
+    Type, TypeParam,
 };
 
-use crate::term_search::{Expr, TermSearchConfig};
+use crate::term_search::Expr;
 
 use super::{LookupTable, NewTypesKey, TermSearchCtx};
 
@@ -74,8 +74,6 @@ pub(super) fn trivial<'a, DB: HirDatabase>(
             _ => None,
         }?;
 
-        lookup.mark_exhausted(*def);
-
         let ty = expr.ty(db);
         lookup.insert(ty.clone(), std::iter::once(expr.clone()));
 
@@ -124,6 +122,10 @@ pub(super) fn assoc_const<'a, DB: HirDatabase>(
         .filter(move |it| it.is_visible_from(db, module))
         .filter_map(AssocItem::as_const)
         .filter_map(|it| {
+            if it.attrs(db).is_unstable() {
+                return None;
+            }
+
             let expr = Expr::Const(it);
             let ty = it.ty(db);
 
@@ -151,163 +153,27 @@ pub(super) fn assoc_const<'a, DB: HirDatabase>(
 /// * `should_continue` - Function that indicates when to stop iterating
 pub(super) fn data_constructor<'a, DB: HirDatabase>(
     ctx: &'a TermSearchCtx<'a, DB>,
-    defs: &'a FxHashSet<ScopeDef>,
+    _defs: &'a FxHashSet<ScopeDef>,
     lookup: &'a mut LookupTable,
     should_continue: &'a dyn std::ops::Fn() -> bool,
 ) -> impl Iterator<Item = Expr> + 'a {
     let db = ctx.sema.db;
     let module = ctx.scope.module();
-    fn variant_helper(
+    lookup
-        db: &dyn HirDatabase,
+        .types_wishlist()
-        lookup: &mut LookupTable,
+        .clone()
-        should_continue: &dyn std::ops::Fn() -> bool,
+        .into_iter()
-        parent_enum: Enum,
+        .chain(iter::once(ctx.goal.clone()))
-        variant: Variant,
+        .filter_map(|ty| ty.as_adt().map(|adt| (adt, ty)))
-        config: &TermSearchConfig,
+        .filter(|_| should_continue())
-    ) -> Vec<(Type, Vec<Expr>)> {
+        .filter_map(move |(adt, ty)| match adt {
-        // Ignore unstable
+            Adt::Struct(strukt) => {
-        if variant.is_unstable(db) {
+                // Ignore unstable or not visible
-            return Vec::new();
+                if strukt.is_unstable(db) || !strukt.is_visible_from(db, module) {
-        }
-
-        let generics = GenericDef::from(variant.parent_enum(db));
-        let Some(type_params) = generics
-            .type_or_const_params(db)
-            .into_iter()
-            .map(|it| it.as_type_param(db))
-            .collect::<Option<Vec<TypeParam>>>()
-        else {
-            // Ignore enums with const generics
-            return Vec::new();
-        };
-
-        // We currently do not check lifetime bounds so ignore all types that have something to do
-        // with them
-        if !generics.lifetime_params(db).is_empty() {
-            return Vec::new();
-        }
-
-        // Only account for stable type parameters for now, unstable params can be default
-        // tho, for example in `Box<T, #[unstable] A: Allocator>`
-        if type_params.iter().any(|it| it.is_unstable(db) && it.default(db).is_none()) {
-            return Vec::new();
-        }
-
-        let non_default_type_params_len =
-            type_params.iter().filter(|it| it.default(db).is_none()).count();
-
-        let enum_ty_shallow = Adt::from(parent_enum).ty(db);
-        let generic_params = lookup
-            .types_wishlist()
-            .clone()
-            .into_iter()
-            .filter(|ty| ty.could_unify_with(db, &enum_ty_shallow))
-            .map(|it| it.type_arguments().collect::<Vec<Type>>())
-            .chain((non_default_type_params_len == 0).then_some(Vec::new()));
-
-        generic_params
-            .filter(|_| should_continue())
-            .filter_map(move |generics| {
-                // Insert default type params
-                let mut g = generics.into_iter();
-                let generics: Vec<_> = type_params
-                    .iter()
-                    .map(|it| it.default(db).or_else(|| g.next()))
-                    .collect::<Option<_>>()?;
-
-                let enum_ty = Adt::from(parent_enum).ty_with_args(db, generics.iter().cloned());
-
-                // Ignore types that have something to do with lifetimes
-                if config.enable_borrowcheck && enum_ty.contains_reference(db) {
                     return None;
                 }
 
-                // Early exit if some param cannot be filled from lookup
+                let generics = GenericDef::from(strukt);
-                let param_exprs: Vec<Vec<Expr>> = variant
-                    .fields(db)
-                    .into_iter()
-                    .map(|field| lookup.find(db, &field.ty_with_args(db, generics.iter().cloned())))
-                    .collect::<Option<_>>()?;
-
-                // Note that we need special case for 0 param constructors because of multi cartesian
-                // product
-                let variant_exprs: Vec<Expr> = if param_exprs.is_empty() {
-                    vec![Expr::Variant { variant, generics, params: Vec::new() }]
-                } else {
-                    param_exprs
-                        .into_iter()
-                        .multi_cartesian_product()
-                        .map(|params| Expr::Variant { variant, generics: generics.clone(), params })
-                        .collect()
-                };
-                lookup.insert(enum_ty.clone(), variant_exprs.iter().cloned());
-
-                Some((enum_ty, variant_exprs))
-            })
-            .collect()
-    }
-    defs.iter()
-        .filter_map(move |def| match def {
-            ScopeDef::ModuleDef(ModuleDef::Variant(it)) => {
-                let variant_exprs = variant_helper(
-                    db,
-                    lookup,
-                    should_continue,
-                    it.parent_enum(db),
-                    *it,
-                    &ctx.config,
-                );
-                if variant_exprs.is_empty() {
-                    return None;
-                }
-                if GenericDef::from(it.parent_enum(db))
-                    .type_or_const_params(db)
-                    .into_iter()
-                    .filter_map(|it| it.as_type_param(db))
-                    .all(|it| it.default(db).is_some())
-                {
-                    lookup.mark_fulfilled(ScopeDef::ModuleDef(ModuleDef::Variant(*it)));
-                }
-                Some(variant_exprs)
-            }
-            ScopeDef::ModuleDef(ModuleDef::Adt(Adt::Enum(enum_))) => {
-                let exprs: Vec<(Type, Vec<Expr>)> = enum_
-                    .variants(db)
-                    .into_iter()
-                    .flat_map(|it| {
-                        variant_helper(db, lookup, should_continue, *enum_, it, &ctx.config)
-                    })
-                    .collect();
-
-                if exprs.is_empty() {
-                    return None;
-                }
-
-                if GenericDef::from(*enum_)
-                    .type_or_const_params(db)
-                    .into_iter()
-                    .filter_map(|it| it.as_type_param(db))
-                    .all(|it| it.default(db).is_some())
-                {
-                    lookup.mark_fulfilled(ScopeDef::ModuleDef(ModuleDef::Adt(Adt::Enum(*enum_))));
-                }
-
-                Some(exprs)
-            }
-            ScopeDef::ModuleDef(ModuleDef::Adt(Adt::Struct(it))) => {
-                // Ignore unstable and not visible
-                if it.is_unstable(db) || !it.is_visible_from(db, module) {
-                    return None;
-                }
-
-                let generics = GenericDef::from(*it);
-
-                // Ignore const params for now
-                let type_params = generics
-                    .type_or_const_params(db)
-                    .into_iter()
-                    .map(|it| it.as_type_param(db))
-                    .collect::<Option<Vec<TypeParam>>>()?;
 
                 // We currently do not check lifetime bounds so ignore all types that have something to do
                 // with them
@@ -315,48 +181,73 @@ pub(super) fn data_constructor<'a, DB: HirDatabase>(
                     return None;
                 }
 
-                // Only account for stable type parameters for now, unstable params can be default
+                if ty.contains_unknown() {
-                // tho, for example in `Box<T, #[unstable] A: Allocator>`
-                if type_params.iter().any(|it| it.is_unstable(db) && it.default(db).is_none()) {
                     return None;
                 }
 
-                let non_default_type_params_len =
+                // Ignore types that have something to do with lifetimes
-                    type_params.iter().filter(|it| it.default(db).is_none()).count();
+                if ctx.config.enable_borrowcheck && ty.contains_reference(db) {
+                    return None;
+                }
+                let fields = strukt.fields(db);
+                // Check if all fields are visible, otherwise we cannot fill them
+                if fields.iter().any(|it| !it.is_visible_from(db, module)) {
+                    return None;
+                }
 
-                let struct_ty_shallow = Adt::from(*it).ty(db);
+                let generics: Vec<_> = ty.type_arguments().collect();
-                let generic_params = lookup
+
-                    .types_wishlist()
+                // Early exit if some param cannot be filled from lookup
-                    .clone()
+                let param_exprs: Vec<Vec<Expr>> = fields
                     .into_iter()
-                    .filter(|ty| ty.could_unify_with(db, &struct_ty_shallow))
+                    .map(|field| lookup.find(db, &field.ty_with_args(db, generics.iter().cloned())))
-                    .map(|it| it.type_arguments().collect::<Vec<Type>>())
+                    .collect::<Option<_>>()?;
-                    .chain((non_default_type_params_len == 0).then_some(Vec::new()));
 
-                let exprs = generic_params
+                // Note that we need special case for 0 param constructors because of multi cartesian
-                    .filter(|_| should_continue())
+                // product
-                    .filter_map(|generics| {
+                let exprs: Vec<Expr> = if param_exprs.is_empty() {
-                        // Insert default type params
+                    vec![Expr::Struct { strukt, generics, params: Vec::new() }]
-                        let mut g = generics.into_iter();
+                } else {
-                        let generics: Vec<_> = type_params
+                    param_exprs
-                            .iter()
+                        .into_iter()
-                            .map(|it| it.default(db).or_else(|| g.next()))
+                        .multi_cartesian_product()
-                            .collect::<Option<_>>()?;
+                        .map(|params| Expr::Struct { strukt, generics: generics.clone(), params })
+                        .collect()
+                };
 
-                        let struct_ty = Adt::from(*it).ty_with_args(db, generics.iter().cloned());
+                lookup.insert(ty.clone(), exprs.iter().cloned());
+                Some((ty, exprs))
+            }
+            Adt::Enum(enum_) => {
+                // Ignore unstable or not visible
+                if enum_.is_unstable(db) || !enum_.is_visible_from(db, module) {
+                    return None;
+                }
 
-                        // Ignore types that have something to do with lifetimes
+                let generics = GenericDef::from(enum_);
-                        if ctx.config.enable_borrowcheck && struct_ty.contains_reference(db) {
+                // We currently do not check lifetime bounds so ignore all types that have something to do
-                            return None;
+                // with them
-                        }
+                if !generics.lifetime_params(db).is_empty() {
-                        let fields = it.fields(db);
+                    return None;
-                        // Check if all fields are visible, otherwise we cannot fill them
+                }
-                        if fields.iter().any(|it| !it.is_visible_from(db, module)) {
-                            return None;
-                        }
 
+                if ty.contains_unknown() {
+                    return None;
+                }
+
+                // Ignore types that have something to do with lifetimes
+                if ctx.config.enable_borrowcheck && ty.contains_reference(db) {
+                    return None;
+                }
+
+                let generics: Vec<_> = ty.type_arguments().collect();
+                let exprs = enum_
+                    .variants(db)
+                    .into_iter()
+                    .filter_map(|variant| {
                         // Early exit if some param cannot be filled from lookup
-                        let param_exprs: Vec<Vec<Expr>> = fields
+                        let param_exprs: Vec<Vec<Expr>> = variant
+                            .fields(db)
                             .into_iter()
                             .map(|field| {
                                 lookup.find(db, &field.ty_with_args(db, generics.iter().cloned()))
@@ -365,36 +256,33 @@ pub(super) fn data_constructor<'a, DB: HirDatabase>(
 
                         // Note that we need special case for 0 param constructors because of multi cartesian
                         // product
-                        let struct_exprs: Vec<Expr> = if param_exprs.is_empty() {
+                        let variant_exprs: Vec<Expr> = if param_exprs.is_empty() {
-                            vec![Expr::Struct { strukt: *it, generics, params: Vec::new() }]
+                            vec![Expr::Variant {
+                                variant,
+                                generics: generics.clone(),
+                                params: Vec::new(),
+                            }]
                         } else {
                             param_exprs
                                 .into_iter()
                                 .multi_cartesian_product()
-                                .map(|params| Expr::Struct {
+                                .map(|params| Expr::Variant {
-                                    strukt: *it,
+                                    variant,
                                     generics: generics.clone(),
                                     params,
                                 })
                                 .collect()
                         };
-
+                        lookup.insert(ty.clone(), variant_exprs.iter().cloned());
-                        if non_default_type_params_len == 0 {
+                        Some(variant_exprs)
-                            // Fulfilled only if there are no generic parameters
-                            lookup.mark_fulfilled(ScopeDef::ModuleDef(ModuleDef::Adt(
-                                Adt::Struct(*it),
-                            )));
-                        }
-                        lookup.insert(struct_ty.clone(), struct_exprs.iter().cloned());
-
-                        Some((struct_ty, struct_exprs))
                     })
+                    .flatten()
                     .collect();
-                Some(exprs)
+
+                Some((ty, exprs))
             }
-            _ => None,
+            Adt::Union(_) => None,
         })
-        .flatten()
         .filter_map(|(ty, exprs)| ty.could_unify_with_deeply(db, &ctx.goal).then_some(exprs))
         .flatten()
 }
@@ -515,7 +403,6 @@ pub(super) fn free_function<'a, DB: HirDatabase>(
                                 .collect()
                         };
 
-                        lookup.mark_fulfilled(ScopeDef::ModuleDef(ModuleDef::Function(*it)));
                         lookup.insert(ret_ty.clone(), fn_exprs.iter().cloned());
                         Some((ret_ty, fn_exprs))
                     })
@@ -555,6 +442,8 @@ pub(super) fn impl_method<'a, DB: HirDatabase>(
     lookup
         .new_types(NewTypesKey::ImplMethod)
         .into_iter()
+        .filter(|ty| !ty.type_arguments().any(|it| it.contains_unknown()))
+        .filter(|_| should_continue())
         .flat_map(|ty| {
             Impl::all_for_type(db, ty.clone()).into_iter().map(move |imp| (ty.clone(), imp))
         })
@@ -563,26 +452,15 @@ pub(super) fn impl_method<'a, DB: HirDatabase>(
             AssocItem::Function(f) => Some((imp, ty, f)),
             _ => None,
         })
+        .filter(|_| should_continue())
         .filter_map(move |(imp, ty, it)| {
             let fn_generics = GenericDef::from(it);
             let imp_generics = GenericDef::from(imp);
 
-            // Ignore const params for now
-            let imp_type_params = imp_generics
-                .type_or_const_params(db)
-                .into_iter()
-                .map(|it| it.as_type_param(db))
-                .collect::<Option<Vec<TypeParam>>>()?;
-
-            // Ignore const params for now
-            let fn_type_params = fn_generics
-                .type_or_const_params(db)
-                .into_iter()
-                .map(|it| it.as_type_param(db))
-                .collect::<Option<Vec<TypeParam>>>()?;
-
             // Ignore all functions that have something to do with lifetimes as we don't check them
-            if !fn_generics.lifetime_params(db).is_empty() {
+            if !fn_generics.lifetime_params(db).is_empty()
+                || !imp_generics.lifetime_params(db).is_empty()
+            {
                 return None;
             }
 
@@ -596,112 +474,59 @@ pub(super) fn impl_method<'a, DB: HirDatabase>(
                 return None;
             }
 
-            // Only account for stable type parameters for now, unstable params can be default
+            // Ignore functions with generics for now as they kill the performance
-            // tho, for example in `Box<T, #[unstable] A: Allocator>`
+            // Also checking bounds for generics is problematic
-            if imp_type_params.iter().any(|it| it.is_unstable(db) && it.default(db).is_none())
+            if !fn_generics.type_or_const_params(db).is_empty() {
-                || fn_type_params.iter().any(|it| it.is_unstable(db) && it.default(db).is_none())
+                return None;
+            }
+
+            let ret_ty = it.ret_type_with_args(db, ty.type_arguments());
+            // Filter out functions that return references
+            if ctx.config.enable_borrowcheck && ret_ty.contains_reference(db) || ret_ty.is_raw_ptr()
             {
                 return None;
             }
 
-            // Double check that we have fully known type
+            // Ignore functions that do not change the type
-            if ty.type_arguments().any(|it| it.contains_unknown()) {
+            if ty.could_unify_with_deeply(db, &ret_ty) {
                 return None;
             }
 
-            let non_default_fn_type_params_len =
+            let self_ty =
-                fn_type_params.iter().filter(|it| it.default(db).is_none()).count();
+                it.self_param(db).expect("No self param").ty_with_args(db, ty.type_arguments());
 
-            // Ignore functions with generics for now as they kill the performance
+            // Ignore functions that have different self type
-            // Also checking bounds for generics is problematic
+            if !self_ty.autoderef(db).any(|s_ty| ty == s_ty) {
-            if non_default_fn_type_params_len > 0 {
                 return None;
             }
 
-            let generic_params = lookup
+            let target_type_exprs = lookup.find(db, &ty).expect("Type not in lookup");
-                .iter_types()
+
-                .collect::<Vec<_>>() // Force take ownership
+            // Early exit if some param cannot be filled from lookup
+            let param_exprs: Vec<Vec<Expr>> = it
+                .params_without_self_with_args(db, ty.type_arguments())
                 .into_iter()
-                .permutations(non_default_fn_type_params_len);
+                .map(|field| lookup.find_autoref(db, field.ty()))
+                .collect::<Option<_>>()?;
 
-            let exprs: Vec<_> = generic_params
+            let generics: Vec<_> = ty.type_arguments().collect();
-                .filter(|_| should_continue())
+            let fn_exprs: Vec<Expr> = std::iter::once(target_type_exprs)
-                .filter_map(|generics| {
+                .chain(param_exprs)
-                    // Insert default type params
+                .multi_cartesian_product()
-                    let mut g = generics.into_iter();
+                .map(|params| {
-                    let generics: Vec<_> = ty
+                    let mut params = params.into_iter();
-                        .type_arguments()
+                    let target = Box::new(params.next().unwrap());
-                        .map(Some)
+                    Expr::Method {
-                        .chain(fn_type_params.iter().map(|it| match it.default(db) {
+                        func: it,
-                            Some(ty) => Some(ty),
+                        generics: generics.clone(),
-                            None => {
+                        target,
-                                let generic = g.next().expect("Missing type param");
+                        params: params.collect(),
-                                // Filter out generics that do not unify due to trait bounds
-                                it.ty(db).could_unify_with(db, &generic).then_some(generic)
-                            }
-                        }))
-                        .collect::<Option<_>>()?;
-
-                    let ret_ty = it.ret_type_with_args(
-                        db,
-                        ty.type_arguments().chain(generics.iter().cloned()),
-                    );
-                    // Filter out functions that return references
-                    if ctx.config.enable_borrowcheck && ret_ty.contains_reference(db)
-                        || ret_ty.is_raw_ptr()
-                    {
-                        return None;
                     }
-
-                    // Ignore functions that do not change the type
-                    if ty.could_unify_with_deeply(db, &ret_ty) {
-                        return None;
-                    }
-
-                    let self_ty = it
-                        .self_param(db)
-                        .expect("No self param")
-                        .ty_with_args(db, ty.type_arguments().chain(generics.iter().cloned()));
-
-                    // Ignore functions that have different self type
-                    if !self_ty.autoderef(db).any(|s_ty| ty == s_ty) {
-                        return None;
-                    }
-
-                    let target_type_exprs = lookup.find(db, &ty).expect("Type not in lookup");
-
-                    // Early exit if some param cannot be filled from lookup
-                    let param_exprs: Vec<Vec<Expr>> = it
-                        .params_without_self_with_args(
-                            db,
-                            ty.type_arguments().chain(generics.iter().cloned()),
-                        )
-                        .into_iter()
-                        .map(|field| lookup.find_autoref(db, field.ty()))
-                        .collect::<Option<_>>()?;
-
-                    let fn_exprs: Vec<Expr> = std::iter::once(target_type_exprs)
-                        .chain(param_exprs)
-                        .multi_cartesian_product()
-                        .map(|params| {
-                            let mut params = params.into_iter();
-                            let target = Box::new(params.next().unwrap());
-                            Expr::Method {
-                                func: it,
-                                generics: generics.clone(),
-                                target,
-                                params: params.collect(),
-                            }
-                        })
-                        .collect();
-
-                    lookup.insert(ret_ty.clone(), fn_exprs.iter().cloned());
-                    Some((ret_ty, fn_exprs))
                 })
                 .collect();
-            Some(exprs)
+
+            Some((ret_ty, fn_exprs))
         })
-        .flatten()
         .filter_map(|(ty, exprs)| ty.could_unify_with_deeply(db, &ctx.goal).then_some(exprs))
         .flatten()
 }
@@ -773,9 +598,8 @@ pub(super) fn famous_types<'a, DB: HirDatabase>(
         Expr::FamousType { ty: Type::new(db, module.id, TyBuilder::unit()), value: "()" },
     ]
     .into_iter()
-    .map(|exprs| {
+    .inspect(|exprs| {
         lookup.insert(exprs.ty(db), std::iter::once(exprs.clone()));
-        exprs
     })
     .filter(|expr| expr.ty(db).could_unify_with_deeply(db, &ctx.goal))
 }
@@ -805,6 +629,7 @@ pub(super) fn impl_static_method<'a, DB: HirDatabase>(
         .clone()
         .into_iter()
         .chain(iter::once(ctx.goal.clone()))
+        .filter(|ty| !ty.type_arguments().any(|it| it.contains_unknown()))
         .filter(|_| should_continue())
         .flat_map(|ty| {
             Impl::all_for_type(db, ty.clone()).into_iter().map(move |imp| (ty.clone(), imp))
@@ -815,24 +640,11 @@ pub(super) fn impl_static_method<'a, DB: HirDatabase>(
             AssocItem::Function(f) => Some((imp, ty, f)),
             _ => None,
         })
+        .filter(|_| should_continue())
         .filter_map(move |(imp, ty, it)| {
             let fn_generics = GenericDef::from(it);
             let imp_generics = GenericDef::from(imp);
 
-            // Ignore const params for now
-            let imp_type_params = imp_generics
-                .type_or_const_params(db)
-                .into_iter()
-                .map(|it| it.as_type_param(db))
-                .collect::<Option<Vec<TypeParam>>>()?;
-
-            // Ignore const params for now
-            let fn_type_params = fn_generics
-                .type_or_const_params(db)
-                .into_iter()
-                .map(|it| it.as_type_param(db))
-                .collect::<Option<Vec<TypeParam>>>()?;
-
             // Ignore all functions that have something to do with lifetimes as we don't check them
             if !fn_generics.lifetime_params(db).is_empty()
                 || !imp_generics.lifetime_params(db).is_empty()
@@ -850,104 +662,43 @@ pub(super) fn impl_static_method<'a, DB: HirDatabase>(
                 return None;
             }
 
-            // Only account for stable type parameters for now, unstable params can be default
+            // Ignore functions with generics for now as they kill the performance
-            // tho, for example in `Box<T, #[unstable] A: Allocator>`
+            // Also checking bounds for generics is problematic
-            if imp_type_params.iter().any(|it| it.is_unstable(db) && it.default(db).is_none())
+            if !fn_generics.type_or_const_params(db).is_empty() {
-                || fn_type_params.iter().any(|it| it.is_unstable(db) && it.default(db).is_none())
+                return None;
+            }
+
+            let ret_ty = it.ret_type_with_args(db, ty.type_arguments());
+            // Filter out functions that return references
+            if ctx.config.enable_borrowcheck && ret_ty.contains_reference(db) || ret_ty.is_raw_ptr()
             {
                 return None;
             }
 
-            // Double check that we have fully known type
+            // Early exit if some param cannot be filled from lookup
-            if ty.type_arguments().any(|it| it.contains_unknown()) {
+            let param_exprs: Vec<Vec<Expr>> = it
-                return None;
+                .params_without_self_with_args(db, ty.type_arguments())
-            }
-
-            let non_default_fn_type_params_len =
-                fn_type_params.iter().filter(|it| it.default(db).is_none()).count();
-
-            // Ignore functions with generics for now as they kill the performance
-            // Also checking bounds for generics is problematic
-            if non_default_fn_type_params_len > 0 {
-                return None;
-            }
-
-            let generic_params = lookup
-                .iter_types()
-                .collect::<Vec<_>>() // Force take ownership
                 .into_iter()
-                .permutations(non_default_fn_type_params_len);
+                .map(|field| lookup.find_autoref(db, field.ty()))
+                .collect::<Option<_>>()?;
 
-            let exprs: Vec<_> = generic_params
+            // Note that we need special case for 0 param constructors because of multi cartesian
-                .filter(|_| should_continue())
+            // product
-                .filter_map(|generics| {
+            let generics = ty.type_arguments().collect();
-                    // Insert default type params
+            let fn_exprs: Vec<Expr> = if param_exprs.is_empty() {
-                    let mut g = generics.into_iter();
+                vec![Expr::Function { func: it, generics, params: Vec::new() }]
-                    let generics: Vec<_> = ty
+            } else {
-                        .type_arguments()
+                param_exprs
-                        .map(Some)
+                    .into_iter()
-                        .chain(fn_type_params.iter().map(|it| match it.default(db) {
+                    .multi_cartesian_product()
-                            Some(ty) => Some(ty),
+                    .map(|params| Expr::Function { func: it, generics: generics.clone(), params })
-                            None => {
+                    .collect()
-                                let generic = g.next().expect("Missing type param");
+            };
-                                it.trait_bounds(db)
-                                    .into_iter()
-                                    .all(|bound| generic.impls_trait(db, bound, &[]));
-                                // Filter out generics that do not unify due to trait bounds
-                                it.ty(db).could_unify_with(db, &generic).then_some(generic)
-                            }
-                        }))
-                        .collect::<Option<_>>()?;
 
-                    let ret_ty = it.ret_type_with_args(
+            lookup.insert(ret_ty.clone(), fn_exprs.iter().cloned());
-                        db,
-                        ty.type_arguments().chain(generics.iter().cloned()),
-                    );
-                    // Filter out functions that return references
-                    if ctx.config.enable_borrowcheck && ret_ty.contains_reference(db)
-                        || ret_ty.is_raw_ptr()
-                    {
-                        return None;
-                    }
 
-                    // Ignore functions that do not change the type
+            Some((ret_ty, fn_exprs))
-                    // if ty.could_unify_with_deeply(db, &ret_ty) {
-                    //     return None;
-                    // }
-
-                    // Early exit if some param cannot be filled from lookup
-                    let param_exprs: Vec<Vec<Expr>> = it
-                        .params_without_self_with_args(
-                            db,
-                            ty.type_arguments().chain(generics.iter().cloned()),
-                        )
-                        .into_iter()
-                        .map(|field| lookup.find_autoref(db, field.ty()))
-                        .collect::<Option<_>>()?;
-
-                    // Note that we need special case for 0 param constructors because of multi cartesian
-                    // product
-                    let fn_exprs: Vec<Expr> = if param_exprs.is_empty() {
-                        vec![Expr::Function { func: it, generics, params: Vec::new() }]
-                    } else {
-                        param_exprs
-                            .into_iter()
-                            .multi_cartesian_product()
-                            .map(|params| Expr::Function {
-                                func: it,
-                                generics: generics.clone(),
-                                params,
-                            })
-                            .collect()
-                    };
-
-                    lookup.insert(ret_ty.clone(), fn_exprs.iter().cloned());
-                    Some((ret_ty, fn_exprs))
-                })
-                .collect();
-            Some(exprs)
         })
-        .flatten()
         .filter_map(|(ty, exprs)| ty.could_unify_with_deeply(db, &ctx.goal).then_some(exprs))
         .flatten()
 }

crates/ide-assists/src/assist_config.rs

@@ -15,6 +15,8 @@ pub struct AssistConfig {
     pub insert_use: InsertUseConfig,
     pub prefer_no_std: bool,
     pub prefer_prelude: bool,
+    pub prefer_absolute: bool,
     pub assist_emit_must_use: bool,
     pub term_search_fuel: u64,
+    pub term_search_borrowck: bool,
 }

crates/ide-assists/src/handlers/add_missing_match_arms.rs

@@ -74,6 +74,7 @@ pub(crate) fn add_missing_match_arms(acc: &mut Assists, ctx: &AssistContext<'_>)
     let cfg = ImportPathConfig {
         prefer_no_std: ctx.config.prefer_no_std,
         prefer_prelude: ctx.config.prefer_prelude,
+        prefer_absolute: ctx.config.prefer_absolute,
     };
 
     let module = ctx.sema.scope(expr.syntax())?.module();

crates/ide-assists/src/handlers/add_turbo_fish.rs

@@ -1,7 +1,7 @@
 use either::Either;
 use ide_db::defs::{Definition, NameRefClass};
 use syntax::{
-    ast::{self, make, HasArgList},
+    ast::{self, make, HasArgList, HasGenericArgs},
     ted, AstNode,
 };
 

crates/ide-assists/src/handlers/auto_import.rs

@@ -93,6 +93,7 @@ pub(crate) fn auto_import(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<
     let cfg = ImportPathConfig {
         prefer_no_std: ctx.config.prefer_no_std,
         prefer_prelude: ctx.config.prefer_prelude,
+        prefer_absolute: ctx.config.prefer_absolute,
     };
 
     let (import_assets, syntax_under_caret) = find_importable_node(ctx)?;

crates/ide-assists/src/handlers/bool_to_enum.rs

@@ -1,3 +1,4 @@
+use either::Either;
 use hir::{ImportPathConfig, ModuleDef};
 use ide_db::{
     assists::{AssistId, AssistKind},
@@ -76,7 +77,11 @@ pub(crate) fn bool_to_enum(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option
 
             let usages = definition.usages(&ctx.sema).all();
             add_enum_def(edit, ctx, &usages, target_node, &target_module);
-            replace_usages(edit, ctx, usages, definition, &target_module);
+            let mut delayed_mutations = Vec::new();
+            replace_usages(edit, ctx, usages, definition, &target_module, &mut delayed_mutations);
+            for (scope, path) in delayed_mutations {
+                insert_use(&scope, path, &ctx.config.insert_use);
+            }
         },
     )
 }
@@ -91,29 +96,32 @@ struct BoolNodeData {
 
 /// Attempts to find an appropriate node to apply the action to.
 fn find_bool_node(ctx: &AssistContext<'_>) -> Option<BoolNodeData> {
-    let name: ast::Name = ctx.find_node_at_offset()?;
+    let name = ctx.find_node_at_offset::<ast::Name>()?;
 
-    if let Some(let_stmt) = name.syntax().ancestors().find_map(ast::LetStmt::cast) {
+    if let Some(ident_pat) = name.syntax().parent().and_then(ast::IdentPat::cast) {
-        let bind_pat = match let_stmt.pat()? {
+        let def = ctx.sema.to_def(&ident_pat)?;
-            ast::Pat::IdentPat(pat) => pat,
-            _ => {
-                cov_mark::hit!(not_applicable_in_non_ident_pat);
-                return None;
-            }
-        };
-        let def = ctx.sema.to_def(&bind_pat)?;
         if !def.ty(ctx.db()).is_bool() {
             cov_mark::hit!(not_applicable_non_bool_local);
             return None;
         }
 
-        Some(BoolNodeData {
+        let local_definition = Definition::Local(def);
-            target_node: let_stmt.syntax().clone(),
+        match ident_pat.syntax().parent().and_then(Either::<ast::Param, ast::LetStmt>::cast)? {
-            name,
+            Either::Left(param) => Some(BoolNodeData {
-            ty_annotation: let_stmt.ty(),
+                target_node: param.syntax().clone(),
-            initializer: let_stmt.initializer(),
+                name,
-            definition: Definition::Local(def),
+                ty_annotation: param.ty(),
-        })
+                initializer: None,
+                definition: local_definition,
+            }),
+            Either::Right(let_stmt) => Some(BoolNodeData {
+                target_node: let_stmt.syntax().clone(),
+                name,
+                ty_annotation: let_stmt.ty(),
+                initializer: let_stmt.initializer(),
+                definition: local_definition,
+            }),
+        }
     } else if let Some(const_) = name.syntax().parent().and_then(ast::Const::cast) {
         let def = ctx.sema.to_def(&const_)?;
         if !def.ty(ctx.db()).is_bool() {
@@ -197,6 +205,7 @@ fn replace_usages(
     usages: UsageSearchResult,
     target_definition: Definition,
     target_module: &hir::Module,
+    delayed_mutations: &mut Vec<(ImportScope, ast::Path)>,
 ) {
     for (file_id, references) in usages {
         edit.edit_file(file_id);
@@ -217,6 +226,7 @@ fn replace_usages(
                             def.usages(&ctx.sema).all(),
                             target_definition,
                             target_module,
+                            delayed_mutations,
                         )
                     }
                 } else if let Some(initializer) = find_assignment_usage(&name) {
@@ -255,6 +265,7 @@ fn replace_usages(
                                     def.usages(&ctx.sema).all(),
                                     target_definition,
                                     target_module,
+                                    delayed_mutations,
                                 )
                             }
                         }
@@ -306,7 +317,7 @@ fn replace_usages(
                         ImportScope::Module(it) => ImportScope::Module(edit.make_mut(it)),
                         ImportScope::Block(it) => ImportScope::Block(edit.make_mut(it)),
                     };
-                    insert_use(&scope, path, &ctx.config.insert_use);
+                    delayed_mutations.push((scope, path));
                 }
             },
         )
@@ -329,6 +340,7 @@ fn augment_references_with_imports(
     let cfg = ImportPathConfig {
         prefer_no_std: ctx.config.prefer_no_std,
         prefer_prelude: ctx.config.prefer_prelude,
+        prefer_absolute: ctx.config.prefer_absolute,
     };
 
     references
@@ -449,7 +461,20 @@ fn add_enum_def(
     usages: &UsageSearchResult,
     target_node: SyntaxNode,
     target_module: &hir::Module,
-) {
+) -> Option<()> {
+    let insert_before = node_to_insert_before(target_node);
+
+    if ctx
+        .sema
+        .scope(&insert_before)?
+        .module()
+        .scope(ctx.db(), Some(*target_module))
+        .iter()
+        .any(|(name, _)| name.as_str() == Some("Bool"))
+    {
+        return None;
+    }
+
     let make_enum_pub = usages
         .iter()
         .flat_map(|(_, refs)| refs)
@@ -460,7 +485,6 @@ fn add_enum_def(
         .any(|module| module.nearest_non_block_module(ctx.db()) != *target_module);
     let enum_def = make_bool_enum(make_enum_pub);
 
-    let insert_before = node_to_insert_before(target_node);
     let indent = IndentLevel::from_node(&insert_before);
     enum_def.reindent_to(indent);
 
@@ -468,6 +492,8 @@ fn add_enum_def(
         insert_before.text_range().start(),
         format!("{}\n\n{indent}", enum_def.syntax().text()),
     );
+
+    Some(())
 }
 
 /// Finds where to put the new enum definition.
@@ -517,6 +543,125 @@ mod tests {
 
     use crate::tests::{check_assist, check_assist_not_applicable};
 
+    #[test]
+    fn parameter_with_first_param_usage() {
+        check_assist(
+            bool_to_enum,
+            r#"
+fn function($0foo: bool, bar: bool) {
+    if foo {
+        println!("foo");
+    }
+}
+"#,
+            r#"
+#[derive(PartialEq, Eq)]
+enum Bool { True, False }
+
+fn function(foo: Bool, bar: bool) {
+    if foo == Bool::True {
+        println!("foo");
+    }
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn no_duplicate_enums() {
+        check_assist(
+            bool_to_enum,
+            r#"
+#[derive(PartialEq, Eq)]
+enum Bool { True, False }
+
+fn function(foo: bool, $0bar: bool) {
+    if bar {
+        println!("bar");
+    }
+}
+"#,
+            r#"
+#[derive(PartialEq, Eq)]
+enum Bool { True, False }
+
+fn function(foo: bool, bar: Bool) {
+    if bar == Bool::True {
+        println!("bar");
+    }
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn parameter_with_last_param_usage() {
+        check_assist(
+            bool_to_enum,
+            r#"
+fn function(foo: bool, $0bar: bool) {
+    if bar {
+        println!("bar");
+    }
+}
+"#,
+            r#"
+#[derive(PartialEq, Eq)]
+enum Bool { True, False }
+
+fn function(foo: bool, bar: Bool) {
+    if bar == Bool::True {
+        println!("bar");
+    }
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn parameter_with_middle_param_usage() {
+        check_assist(
+            bool_to_enum,
+            r#"
+fn function(foo: bool, $0bar: bool, baz: bool) {
+    if bar {
+        println!("bar");
+    }
+}
+"#,
+            r#"
+#[derive(PartialEq, Eq)]
+enum Bool { True, False }
+
+fn function(foo: bool, bar: Bool, baz: bool) {
+    if bar == Bool::True {
+        println!("bar");
+    }
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn parameter_with_closure_usage() {
+        check_assist(
+            bool_to_enum,
+            r#"
+fn main() {
+    let foo = |$0bar: bool| bar;
+}
+"#,
+            r#"
+#[derive(PartialEq, Eq)]
+enum Bool { True, False }
+
+fn main() {
+    let foo = |bar: Bool| bar == Bool::True;
+}
+"#,
+        )
+    }
+
     #[test]
     fn local_variable_with_usage() {
         check_assist(
@@ -784,7 +929,6 @@ fn main() {
 
     #[test]
     fn local_variable_non_ident_pat() {
-        cov_mark::check!(not_applicable_in_non_ident_pat);
         check_assist_not_applicable(
             bool_to_enum,
             r#"

crates/ide-assists/src/handlers/convert_from_to_tryfrom.rs

@@ -1,7 +1,7 @@
 use ide_db::{famous_defs::FamousDefs, traits::resolve_target_trait};
 use itertools::Itertools;
 use syntax::{
-    ast::{self, make, AstNode, HasName},
+    ast::{self, make, AstNode, HasGenericArgs, HasName},
     ted,
 };
 

crates/ide-assists/src/handlers/convert_into_to_from.rs

@@ -1,6 +1,6 @@
 use hir::ImportPathConfig;
 use ide_db::{famous_defs::FamousDefs, helpers::mod_path_to_ast, traits::resolve_target_trait};
-use syntax::ast::{self, AstNode, HasName};
+use syntax::ast::{self, AstNode, HasGenericArgs, HasName};
 
 use crate::{AssistContext, AssistId, AssistKind, Assists};
 
@@ -47,6 +47,7 @@ pub(crate) fn convert_into_to_from(acc: &mut Assists, ctx: &AssistContext<'_>) -
     let cfg = ImportPathConfig {
         prefer_no_std: ctx.config.prefer_no_std,
         prefer_prelude: ctx.config.prefer_prelude,
+        prefer_absolute: ctx.config.prefer_absolute,
     };
 
     let src_type_path = {

crates/ide-assists/src/handlers/convert_tuple_return_type_to_struct.rs

@@ -186,6 +186,7 @@ fn augment_references_with_imports(
     let cfg = ImportPathConfig {
         prefer_no_std: ctx.config.prefer_no_std,
         prefer_prelude: ctx.config.prefer_prelude,
+        prefer_absolute: ctx.config.prefer_absolute,
     };
 
     references

crates/ide-assists/src/handlers/destructure_struct_binding.rs

@@ -90,6 +90,7 @@ fn collect_data(ident_pat: ast::IdentPat, ctx: &AssistContext<'_>) -> Option<Str
     let cfg = ImportPathConfig {
         prefer_no_std: ctx.config.prefer_no_std,
         prefer_prelude: ctx.config.prefer_prelude,
+        prefer_absolute: ctx.config.prefer_absolute,
     };
 
     let module = ctx.sema.scope(ident_pat.syntax())?.module();

crates/ide-assists/src/handlers/extract_function.rs

@@ -216,6 +216,7 @@ pub(crate) fn extract_function(acc: &mut Assists, ctx: &AssistContext<'_>) -> Op
                         ImportPathConfig {
                             prefer_no_std: ctx.config.prefer_no_std,
                             prefer_prelude: ctx.config.prefer_prelude,
+                            prefer_absolute: ctx.config.prefer_absolute,
                         },
                     );
 

crates/ide-assists/src/handlers/extract_struct_from_enum_variant.rs

@@ -393,6 +393,7 @@ fn process_references(
                     ImportPathConfig {
                         prefer_no_std: ctx.config.prefer_no_std,
                         prefer_prelude: ctx.config.prefer_prelude,
+                        prefer_absolute: ctx.config.prefer_absolute,
                     },
                 );
                 if let Some(mut mod_path) = mod_path {

crates/ide-assists/src/handlers/extract_type_alias.rs

@@ -1,7 +1,7 @@
 use either::Either;
 use ide_db::syntax_helpers::node_ext::walk_ty;
 use syntax::{
-    ast::{self, edit::IndentLevel, make, AstNode, HasGenericParams, HasName},
+    ast::{self, edit::IndentLevel, make, AstNode, HasGenericArgs, HasGenericParams, HasName},
     ted,
 };
 

crates/ide-assists/src/handlers/generate_delegate_trait.rs

@@ -17,8 +17,9 @@ use syntax::{
         self,
         edit::{self, AstNodeEdit},
         edit_in_place::AttrsOwnerEdit,
-        make, AssocItem, GenericArgList, GenericParamList, HasAttrs, HasGenericParams, HasName,
+        make, AssocItem, GenericArgList, GenericParamList, HasAttrs, HasGenericArgs,
-        HasTypeBounds, HasVisibility as astHasVisibility, Path, WherePred,
+        HasGenericParams, HasName, HasTypeBounds, HasVisibility as astHasVisibility, Path,
+        WherePred,
     },
     ted::{self, Position},
     AstNode, NodeOrToken, SmolStr, SyntaxKind,

crates/ide-assists/src/handlers/generate_deref.rs

@@ -64,6 +64,7 @@ fn generate_record_deref(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<(
         ImportPathConfig {
             prefer_no_std: ctx.config.prefer_no_std,
             prefer_prelude: ctx.config.prefer_prelude,
+            prefer_absolute: ctx.config.prefer_absolute,
         },
     )?;
 
@@ -111,6 +112,7 @@ fn generate_tuple_deref(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()
         ImportPathConfig {
             prefer_no_std: ctx.config.prefer_no_std,
             prefer_prelude: ctx.config.prefer_prelude,
+            prefer_absolute: ctx.config.prefer_absolute,
         },
     )?;
 

crates/ide-assists/src/handlers/generate_documentation_template.rs

@@ -4,7 +4,7 @@ use itertools::Itertools;
 use stdx::{format_to, to_lower_snake_case};
 use syntax::{
     algo::skip_whitespace_token,
-    ast::{self, edit::IndentLevel, HasDocComments, HasName},
+    ast::{self, edit::IndentLevel, HasDocComments, HasGenericArgs, HasName},
     match_ast, AstNode, AstToken,
 };
 

crates/ide-assists/src/handlers/generate_new.rs

@@ -65,6 +65,7 @@ pub(crate) fn generate_new(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option
                     ImportPathConfig {
                         prefer_no_std: ctx.config.prefer_no_std,
                         prefer_prelude: ctx.config.prefer_prelude,
+                        prefer_absolute: ctx.config.prefer_absolute,
                     },
                 )?;
 

crates/ide-assists/src/handlers/inline_call.rs

@@ -15,7 +15,9 @@ use ide_db::{
 };
 use itertools::{izip, Itertools};
 use syntax::{
-    ast::{self, edit::IndentLevel, edit_in_place::Indent, HasArgList, Pat, PathExpr},
+    ast::{
+        self, edit::IndentLevel, edit_in_place::Indent, HasArgList, HasGenericArgs, Pat, PathExpr,
+    },
     ted, AstNode, NodeOrToken, SyntaxKind,
 };
 

crates/ide-assists/src/handlers/merge_imports.rs

@@ -489,6 +489,25 @@ use foo::bar;
         );
     }
 
+    #[test]
+    fn test_merge_nested_empty_and_self_with_other() {
+        check_assist(
+            merge_imports,
+            r"
+use foo::$0{bar};
+use foo::{bar::{self, other}};
+",
+            r"
+use foo::bar::{self, other};
+",
+        );
+        check_assist_import_one_variations!(
+            "foo::$0{bar}",
+            "foo::{bar::{self, other}}",
+            "use {foo::bar::{self, other}};"
+        );
+    }
+
     #[test]
     fn test_merge_nested_list_self_and_glob() {
         check_assist(

crates/ide-assists/src/handlers/normalize_import.rs

@@ -119,10 +119,39 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_braces_kept() {
+        check_assist_not_applicable_variations!("foo::bar::{$0self}");
+
+        // This code compiles but transforming "bar::{self}" into "bar" causes a
+        // compilation error (the name `bar` is defined multiple times).
+        // Therefore, the normalize_input assist must not apply here.
+        check_assist_not_applicable(
+            normalize_import,
+            r"
+mod foo {
+
+    pub mod bar {}
+
+    pub const bar: i32 = 8;
+}
+
+use foo::bar::{$0self};
+
+const bar: u32 = 99;
+
+fn main() {
+    let local_bar = bar;
+}
+
+",
+        );
+    }
+
     #[test]
     fn test_redundant_braces() {
         check_assist_variations!("foo::{bar::{baz, Qux}}", "foo::bar::{baz, Qux}");
-        check_assist_variations!("foo::{bar::{self}}", "foo::bar");
+        check_assist_variations!("foo::{bar::{self}}", "foo::bar::{self}");
         check_assist_variations!("foo::{bar::{*}}", "foo::bar::*");
         check_assist_variations!("foo::{bar::{Qux as Quux}}", "foo::bar::Qux as Quux");
         check_assist_variations!(

crates/ide-assists/src/handlers/qualify_method_call.rs

@@ -53,6 +53,7 @@ pub(crate) fn qualify_method_call(acc: &mut Assists, ctx: &AssistContext<'_>) ->
         ImportPathConfig {
             prefer_no_std: ctx.config.prefer_no_std,
             prefer_prelude: ctx.config.prefer_prelude,
+            prefer_absolute: ctx.config.prefer_absolute,
         },
     )?;
 

crates/ide-assists/src/handlers/qualify_path.rs

@@ -6,6 +6,7 @@ use ide_db::{
     helpers::mod_path_to_ast,
     imports::import_assets::{ImportCandidate, LocatedImport},
 };
+use syntax::ast::HasGenericArgs;
 use syntax::{
     ast,
     ast::{make, HasArgList},
@@ -40,6 +41,7 @@ pub(crate) fn qualify_path(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option
     let cfg = ImportPathConfig {
         prefer_no_std: ctx.config.prefer_no_std,
         prefer_prelude: ctx.config.prefer_prelude,
+        prefer_absolute: ctx.config.prefer_absolute,
     };
 
     let mut proposed_imports: Vec<_> =

crates/ide-assists/src/handlers/remove_parentheses.rs

@@ -239,4 +239,33 @@ mod tests {
 
         check_assist_not_applicable(remove_parentheses, r#"fn f() { $0(return 2) + 2 }"#);
     }
+
+    #[test]
+    fn remove_parens_indirect_calls() {
+        check_assist(
+            remove_parentheses,
+            r#"fn f(call: fn(usize), arg: usize) { $0(call)(arg); }"#,
+            r#"fn f(call: fn(usize), arg: usize) { call(arg); }"#,
+        );
+        check_assist(
+            remove_parentheses,
+            r#"fn f<F>(call: F, arg: usize) where F: Fn(usize) { $0(call)(arg); }"#,
+            r#"fn f<F>(call: F, arg: usize) where F: Fn(usize) { call(arg); }"#,
+        );
+
+        // Parentheses are necessary when calling a function-like pointer that is a member of a struct or union.
+        check_assist_not_applicable(
+            remove_parentheses,
+            r#"
+struct Foo<T> {
+    t: T,
+}
+
+impl Foo<fn(usize)> {
+    fn foo(&self, arg: usize) {
+        $0(self.t)(arg);
+    }
+}"#,
+        );
+    }
 }

crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs

@@ -89,6 +89,7 @@ pub(crate) fn replace_derive_with_manual_impl(
                 ImportPathConfig {
                     prefer_no_std: ctx.config.prefer_no_std,
                     prefer_prelude: ctx.config.prefer_prelude,
+                    prefer_absolute: ctx.config.prefer_absolute,
                 },
             )
             .as_ref()

crates/ide-assists/src/handlers/replace_qualified_name_with_use.rs

@@ -4,7 +4,7 @@ use ide_db::{
     imports::insert_use::{insert_use, ImportScope},
 };
 use syntax::{
-    ast::{self, make},
+    ast::{self, make, HasGenericArgs},
     match_ast, ted, AstNode, SyntaxNode,
 };
 
@@ -70,6 +70,7 @@ pub(crate) fn replace_qualified_name_with_use(
                 ImportPathConfig {
                     prefer_no_std: ctx.config.prefer_no_std,
                     prefer_prelude: ctx.config.prefer_prelude,
+                    prefer_absolute: ctx.config.prefer_absolute,
                 },
             )
         })

crates/ide-assists/src/handlers/replace_turbofish_with_explicit_type.rs

@@ -1,7 +1,6 @@
 use hir::HirDisplay;
 use syntax::{
-    ast::{Expr, GenericArg, GenericArgList},
+    ast::{Expr, GenericArg, GenericArgList, HasGenericArgs, LetStmt, Type::InferType},
-    ast::{LetStmt, Type::InferType},
     AstNode, TextRange,
 };
 

crates/ide-assists/src/handlers/term_search.rs

@@ -37,7 +37,11 @@ pub(crate) fn term_search(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<
         sema: &ctx.sema,
         scope: &scope,
         goal: target_ty,
-        config: TermSearchConfig { fuel: ctx.config.term_search_fuel, ..Default::default() },
+        config: TermSearchConfig {
+            fuel: ctx.config.term_search_fuel,
+            enable_borrowcheck: ctx.config.term_search_borrowck,
+            ..Default::default()
+        },
     };
     let paths = hir::term_search::term_search(&term_search_ctx);
 
@@ -56,6 +60,7 @@ pub(crate) fn term_search(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<
                 ImportPathConfig {
                     prefer_no_std: ctx.config.prefer_no_std,
                     prefer_prelude: ctx.config.prefer_prelude,
+                    prefer_absolute: ctx.config.prefer_absolute,
                 },
             )
             .ok()
@@ -144,7 +149,7 @@ fn f() { let a = A { x: 1, y: true }; let b: i32 = a.x; }"#,
             term_search,
             r#"//- minicore: todo, unimplemented, option
 fn f() { let a: i32 = 1; let b: Option<i32> = todo$0!(); }"#,
-            r#"fn f() { let a: i32 = 1; let b: Option<i32> = None; }"#,
+            r#"fn f() { let a: i32 = 1; let b: Option<i32> = Some(a); }"#,
         )
     }
 

crates/ide-assists/src/handlers/toggle_async_sugar.rs

@@ -4,7 +4,7 @@ use ide_db::{
     famous_defs::FamousDefs,
 };
 use syntax::{
-    ast::{self, HasVisibility},
+    ast::{self, HasGenericArgs, HasVisibility},
     AstNode, NodeOrToken, SyntaxKind, SyntaxNode, SyntaxToken, TextRange,
 };
 
@@ -142,6 +142,7 @@ pub(crate) fn desugar_async_into_impl_future(
         ImportPathConfig {
             prefer_no_std: ctx.config.prefer_no_std,
             prefer_prelude: ctx.config.prefer_prelude,
+            prefer_absolute: ctx.config.prefer_absolute,
         },
     )?;
     let trait_path = trait_path.display(ctx.db());