83 files changed, 1170 insertions, 715 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 76a26ea4e..557d5f5f3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4,9 +4,9 @@ version = 3
 
 [[package]]
 name = "addr2line"
-version = "0.14.1"
+version = "0.15.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a55f82cfe485775d02112886f4169bde0c5894d75e79ead7eafe7e40a25e45f7"
+checksum = "03345e98af8f3d786b6d9f656ccfa6ac316d954e92bc4841f0bba20789d5fb5a"
 dependencies = [
  "gimli",
 ]
@@ -72,9 +72,9 @@ checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
 
 [[package]]
 name = "backtrace"
-version = "0.3.58"
+version = "0.3.59"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "88fb5a785d6b44fd9d6700935608639af1b8356de1e55d5f7c2740f4faa15d82"
+checksum = "4717cfcbfaa661a0fd48f8453951837ae7e8f81e481fbb136e3202d72805a744"
 dependencies = [
  "addr2line",
  "cc",
@@ -169,9 +169,9 @@ checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
 [[package]]
 name = "chalk-derive"
-version = "0.64.0"
+version = "0.67.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9acf2a9eab79ae7d44cd77ad86a8b1569d7a5e6d9a7db4a0a57a7344dd82c24"
+checksum = "751a3cd9eeb24d7165e9f90daf1f10a23ffa16a7986f349027f8dfb60f51ee0c"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -181,9 +181,9 @@ dependencies = [
 
 [[package]]
 name = "chalk-ir"
-version = "0.64.0"
+version = "0.67.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "877661627f54ba3666a72943c43b326cb170d60899e50a8426111e7a657ff032"
+checksum = "4236da905504740d3f72cc8f0509aa01321cc236208e2c33b55eda2db74bc495"
 dependencies = [
  "bitflags",
  "chalk-derive",
@@ -192,9 +192,9 @@ dependencies = [
 
 [[package]]
 name = "chalk-recursive"
-version = "0.64.0"
+version = "0.67.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "072ffcf17243c2aa3e4b9ea6de3d29e7ef64cfdb0ceccaa431965070a1dc1475"
+checksum = "7d0b123fe45a34c4cd5cb329650a0d163525d2acbe9d754a4538d3340884002e"
 dependencies = [
  "chalk-derive",
  "chalk-ir",
@@ -205,9 +205,9 @@ dependencies = [
 
 [[package]]
 name = "chalk-solve"
-version = "0.64.0"
+version = "0.67.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "97d4920c9ef2b26dd0b98ffdf070e27fa31e0b6f637463132083cee597e3d326"
+checksum = "9c54788f0ae3b38e2bb2266f395d462d988c64f92dbd55c68219908fd1ce7ddc"
 dependencies = [
  "chalk-derive",
  "chalk-ir",
@@ -452,9 +452,9 @@ checksum = "e398fae362f4124bbe630d99519fb2d68a03e2e3a23b441028cdcdc4f4895687"
 
 [[package]]
 name = "gimli"
-version = "0.23.0"
+version = "0.24.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f6503fe142514ca4799d4c26297c4248239fe8838d827db6bd6065c6ed29a6ce"
+checksum = "0e4075386626662786ddb0ec9081e7c7eeb1ba31951f447ca780ef9f5d568189"
 
 [[package]]
 name = "hashbrown"
@@ -715,9 +715,9 @@ dependencies = [
 
 [[package]]
 name = "inotify"
-version = "0.9.2"
+version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d19f57db1baad9d09e43a3cd76dcf82ebdafd37d75c9498b87762dba77c93f15"
+checksum = "b031475cb1b103ee221afb806a23d35e0570bf7271d7588762ceba8127ed43b3"
 dependencies = [
  "bitflags",
  "inotify-sys",
@@ -830,9 +830,9 @@ dependencies = [
 
 [[package]]
 name = "lsp-types"
-version = "0.89.0"
+version = "0.89.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "07731ecd4ee0654728359a5b95e2a254c857876c04b85225496a35d60345daa7"
+checksum = "48b8a871b0a450bcec0e26d74a59583c8173cb9fb7d7f98889e18abb84838e0f"
 dependencies = [
  "bitflags",
  "serde",
@@ -995,9 +995,9 @@ dependencies = [
 
 [[package]]
 name = "object"
-version = "0.23.0"
+version = "0.24.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a9a7ab5d64814df0fe4a4b5ead45ed6c5f181ee3ff04ba344313a6c80446c5d4"
+checksum = "1a5b3dd1c072ee7963717671d1ca129f1048fda25edea6b752bfc71ac8854170"
 
 [[package]]
 name = "once_cell"
@@ -1124,9 +1124,9 @@ checksum = "dbf0c48bc1d91375ae5c3cd81e3722dff1abcf81a30960240640d223f59fe0e5"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.26"
+version = "1.0.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a152013215dca273577e18d2bf00fa862b89b24169fb78c4c95aeb07992c9cec"
+checksum = "f0d8caf72986c1a598726adc988bb5984792ef84f5ee5aa50209145ee8077038"
 dependencies = [
  "unicode-xid",
 ]
@@ -1235,9 +1235,9 @@ dependencies = [
 
 [[package]]
 name = "rayon"
-version = "1.5.0"
+version = "1.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8b0d8e0819fadc20c74ea8373106ead0600e3a67ef1fe8da56e39b9ae7275674"
+checksum = "c06aca804d41dbc8ba42dfd964f0d01334eceb64314b9ecf7c5fad5188a06d90"
 dependencies = [
  "autocfg",
  "crossbeam-deque",
@@ -1247,9 +1247,9 @@ dependencies = [
 
 [[package]]
 name = "rayon-core"
-version = "1.9.0"
+version = "1.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9ab346ac5921dc62ffa9f89b7a773907511cdfa5490c572ae9be1be33e8afa4a"
+checksum = "d78120e2c850279833f1dd3582f730c4ab53ed95aeaaaa862a2a5c71b1656d8e"
 dependencies = [
  "crossbeam-channel",
  "crossbeam-deque",
@@ -1260,18 +1260,18 @@ dependencies = [
 
 [[package]]
 name = "redox_syscall"
-version = "0.2.7"
+version = "0.2.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "85dd92e586f7355c633911e11f77f3d12f04b1b1bd76a198bd34ae3af8341ef2"
+checksum = "742739e41cd49414de871ea5e549afb7e2a3ac77b589bcbebe8c82fab37147fc"
 dependencies = [
  "bitflags",
 ]
 
 [[package]]
 name = "regex"
-version = "1.5.3"
+version = "1.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ce5f1ceb7f74abbce32601642fcf8e8508a8a8991e0621c7d750295b9095702b"
+checksum = "d07a8629359eb56f1e2fb1652bb04212c072a87ba68546a04065d525673ac461"
 dependencies = [
  "regex-syntax",
 ]
@@ -1359,18 +1359,18 @@ dependencies = [
 
 [[package]]
 name = "rustc-ap-rustc_lexer"
-version = "716.0.0"
+version = "720.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "12eac7554c1d3f49f105f14d53c0f3402220e875983113562701d8e597a0995c"
+checksum = "a025b453b0ae85335336f991f920ca9af5c0dc851171cb9035a16cea5619e9b2"
 dependencies = [
  "unicode-xid",
 ]
 
 [[package]]
 name = "rustc-demangle"
-version = "0.1.18"
+version = "0.1.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6e3bad0ee36814ca07d7968269dd4b7ec89ec2da10c4bb613928d3077083c232"
+checksum = "410f7acf3cb3a44527c5d9546bad4bf4e6c460915d5f9f2fc524498bfe8f70ce"
 
 [[package]]
 name = "rustc-hash"
@@ -1455,18 +1455,18 @@ dependencies = [
 
 [[package]]
 name = "serde"
-version = "1.0.125"
+version = "1.0.126"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "558dc50e1a5a5fa7112ca2ce4effcb321b0300c0d4ccf0776a9f60cd89031171"
+checksum = "ec7505abeacaec74ae4778d9d9328fe5a5d04253220a85c4ee022239fc996d03"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.125"
+version = "1.0.126"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b093b7a2bb58203b5da3056c05b4ec1fed827dcfdb37347a8841695263b3d06d"
+checksum = "963a7dbc9895aeac7ac90e74f34a5d5261828f79df35cbed41e10189d3804d43"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1496,9 +1496,9 @@ dependencies = [
 
 [[package]]
 name = "serde_repr"
-version = "0.1.6"
+version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2dc6b7951b17b051f3210b063f12cc17320e2fe30ae05b0fe2a3abb068551c76"
+checksum = "98d0516900518c29efa217c298fa1f4e6c6ffc85ae29fd7f4ee48f176e1a9ed5"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1548,9 +1548,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.71"
+version = "1.0.72"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ad184cc9470f9117b2ac6817bfe297307418819ba40552f9b3846f05c33d5373"
+checksum = "a1e8cdbefb79a9a5a65e0db8b47b723ee907b7c7f8496c76a1770b5c310bab82"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1848,9 +1848,9 @@ checksum = "8ccb82d61f80a663efe1f787a51b16b5a51e3314d6ac365b08639f52387b33f3"
 
 [[package]]
 name = "url"
-version = "2.2.1"
+version = "2.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9ccd964113622c8e9322cfac19eb1004a07e636c545f325da085d5cdde6f1f8b"
+checksum = "a507c383b2d33b5fc35d1861e77e6b383d158b2da5e14fe51b83dfedf6fd578c"
 dependencies = [
  "form_urlencoded",
  "idna",
@@ -1957,18 +1957,18 @@ dependencies = [
 
 [[package]]
 name = "xshell"
-version = "0.1.10"
+version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "aa25217c682f9f991d7889238a99e65eb8431c266d36e0f4e850a73773415473"
+checksum = "eb15bb1b41eb14efe628006294c294e10c366e03a0283b9c2063fc27d97934c6"
 dependencies = [
  "xshell-macros",
 ]
 
 [[package]]
 name = "xshell-macros"
-version = "0.1.10"
+version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4404d53d2113af4fa31c58326eb7b37d6d7bf11ba87520787cddeaff45385c72"
+checksum = "cf7ed94a2c75b9bcc57031229be2b57ee47ba71122f71aabef8610ec66a97e52"
 
 [[package]]
 name = "xtask"
diff --git a/crates/base_db/src/input.rs b/crates/base_db/src/input.rs
index 0ef77ef5d..64ccd11ee 100644
--- a/crates/base_db/src/input.rs
+++ b/crates/base_db/src/input.rs
@@ -53,11 +53,15 @@ impl SourceRoot {
 }
 
 /// `CrateGraph` is a bit of information which turns a set of text files into a
-/// number of Rust crates. Each crate is defined by the `FileId` of its root module,
-/// the set of cfg flags (not yet implemented) and the set of dependencies. Note
-/// that, due to cfg's, there might be several crates for a single `FileId`! As
-/// in the rust-lang proper, a crate does not have a name. Instead, names are
-/// specified on dependency edges. That is, a crate might be known under
+/// number of Rust crates.
+///
+/// Each crate is defined by the `FileId` of its root module, the set of enabled
+/// `cfg` flags and the set of dependencies.
+///
+/// Note that, due to cfg's, there might be several crates for a single `FileId`!
+///
+/// For the purposes of analysis, a crate does not have a name. Instead, names
+/// are specified on dependency edges. That is, a crate might be known under
 /// different names in different dependent crates.
 ///
 /// Note that `CrateGraph` is build-system agnostic: it's a concept of the Rust
diff --git a/crates/hir/src/display.rs b/crates/hir/src/display.rs
index 508ac37c2..c5cf803fd 100644
--- a/crates/hir/src/display.rs
+++ b/crates/hir/src/display.rs
@@ -92,7 +92,7 @@ impl HirDisplay for Function {
             &data.ret_type
         } else {
             match &*data.ret_type {
-                TypeRef::ImplTrait(bounds) => match &bounds[0] {
+                TypeRef::ImplTrait(bounds) => match bounds[0].as_ref() {
                     TypeBound::Path(path) => {
                         path.segments().iter().last().unwrap().args_and_bindings.unwrap().bindings
                             [0]
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index ec5f0c53d..cdf65a044 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -513,9 +513,8 @@ impl Field {
     }
 
     /// Returns the type as in the signature of the struct (i.e., with
-    /// placeholder types for type parameters). This is good for showing
-    /// signature help, but not so good to actually get the type of the field
-    /// when you actually have a variable of the struct.
+    /// placeholder types for type parameters). Only use this in the context of
+    /// the field definition.
     pub fn ty(&self, db: &dyn HirDatabase) -> Type {
         let var_id = self.parent.into();
         let generic_def_id: GenericDefId = match self.parent {
diff --git a/crates/hir/src/semantics.rs b/crates/hir/src/semantics.rs
index 1b5064b5a..8d3c43d08 100644
--- a/crates/hir/src/semantics.rs
+++ b/crates/hir/src/semantics.rs
@@ -11,7 +11,7 @@ use hir_def::{
     AsMacroCall, FunctionId, TraitId, VariantId,
 };
 use hir_expand::{name::AsName, ExpansionInfo};
-use hir_ty::associated_type_shorthand_candidates;
+use hir_ty::{associated_type_shorthand_candidates, Interner};
 use itertools::Itertools;
 use rustc_hash::{FxHashMap, FxHashSet};
 use syntax::{
@@ -120,10 +120,10 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
     pub fn speculative_expand(
         &self,
         actual_macro_call: &ast::MacroCall,
-        hypothetical_args: &ast::TokenTree,
+        speculative_args: &ast::TokenTree,
         token_to_map: SyntaxToken,
     ) -> Option<(SyntaxNode, SyntaxToken)> {
-        self.imp.speculative_expand(actual_macro_call, hypothetical_args, token_to_map)
+        self.imp.speculative_expand(actual_macro_call, speculative_args, token_to_map)
     }
 
     pub fn descend_into_macros(&self, token: SyntaxToken) -> SyntaxToken {
@@ -227,7 +227,7 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
     pub fn resolve_record_field(
         &self,
         field: &ast::RecordExprField,
-    ) -> Option<(Field, Option<Local>)> {
+    ) -> Option<(Field, Option<Local>, Type)> {
         self.imp.resolve_record_field(field)
     }
 
@@ -335,7 +335,7 @@ impl<'db> SemanticsImpl<'db> {
     fn speculative_expand(
         &self,
         actual_macro_call: &ast::MacroCall,
-        hypothetical_args: &ast::TokenTree,
+        speculative_args: &ast::TokenTree,
         token_to_map: SyntaxToken,
     ) -> Option<(SyntaxNode, SyntaxToken)> {
         let sa = self.analyze(actual_macro_call.syntax());
@@ -344,10 +344,10 @@ impl<'db> SemanticsImpl<'db> {
         let macro_call_id = macro_call.as_call_id(self.db.upcast(), krate, |path| {
             sa.resolver.resolve_path_as_macro(self.db.upcast(), &path)
         })?;
-        hir_expand::db::expand_hypothetical(
+        hir_expand::db::expand_speculative(
             self.db.upcast(),
             macro_call_id,
-            hypothetical_args,
+            speculative_args,
             token_to_map,
         )
     }
@@ -501,14 +501,12 @@ impl<'db> SemanticsImpl<'db> {
     }
 
     fn resolve_method_call(&self, call: &ast::MethodCallExpr) -> Option<FunctionId> {
-        self.analyze(call.syntax()).resolve_method_call(self.db, call)
+        self.analyze(call.syntax()).resolve_method_call(self.db, call).map(|(id, _)| id)
     }
 
     fn resolve_method_call_as_callable(&self, call: &ast::MethodCallExpr) -> Option<Callable> {
-        // FIXME: this erases Substs, we should instead record the correct
-        // substitution during inference and use that
-        let func = self.resolve_method_call(call)?;
-        let ty = hir_ty::TyBuilder::value_ty(self.db, func.into()).fill_with_unknown().build();
+        let (func, subst) = self.analyze(call.syntax()).resolve_method_call(self.db, call)?;
+        let ty = self.db.value_ty(func.into()).substitute(&Interner, &subst);
         let resolver = self.analyze(call.syntax()).resolver;
         let ty = Type::new_with_resolver(self.db, &resolver, ty)?;
         let mut res = ty.as_callable(self.db)?;
@@ -520,7 +518,10 @@ impl<'db> SemanticsImpl<'db> {
         self.analyze(field.syntax()).resolve_field(self.db, field)
     }
 
-    fn resolve_record_field(&self, field: &ast::RecordExprField) -> Option<(Field, Option<Local>)> {
+    fn resolve_record_field(
+        &self,
+        field: &ast::RecordExprField,
+    ) -> Option<(Field, Option<Local>, Type)> {
         self.analyze(field.syntax()).resolve_record_field(self.db, field)
     }
 
diff --git a/crates/hir/src/source_analyzer.rs b/crates/hir/src/source_analyzer.rs
index b5c65808e..3f940124c 100644
--- a/crates/hir/src/source_analyzer.rs
+++ b/crates/hir/src/source_analyzer.rs
@@ -143,7 +143,7 @@ impl SourceAnalyzer {
         &self,
         db: &dyn HirDatabase,
         call: &ast::MethodCallExpr,
-    ) -> Option<FunctionId> {
+    ) -> Option<(FunctionId, Substitution)> {
         let expr_id = self.expr_id(db, &call.clone().into())?;
         self.infer.as_ref()?.method_resolution(expr_id)
     }
@@ -161,7 +161,7 @@ impl SourceAnalyzer {
         &self,
         db: &dyn HirDatabase,
         field: &ast::RecordExprField,
-    ) -> Option<(Field, Option<Local>)> {
+    ) -> Option<(Field, Option<Local>, Type)> {
         let record_expr = ast::RecordExpr::cast(field.syntax().parent().and_then(|p| p.parent())?)?;
         let expr = ast::Expr::from(record_expr);
         let expr_id = self.body_source_map.as_ref()?.node_expr(InFile::new(self.file_id, &expr))?;
@@ -178,10 +178,13 @@ impl SourceAnalyzer {
                 _ => None,
             }
         };
+        let (_, subst) = self.infer.as_ref()?.type_of_expr.get(expr_id)?.as_adt()?;
         let variant = self.infer.as_ref()?.variant_resolution_for_expr(expr_id)?;
         let variant_data = variant.variant_data(db.upcast());
         let field = FieldId { parent: variant, local_id: variant_data.field(&local_name)? };
-        Some((field.into(), local))
+        let field_ty =
+            db.field_types(variant).get(field.local_id)?.clone().substitute(&Interner, subst);
+        Some((field.into(), local, Type::new_with_resolver(db, &self.resolver, field_ty)?))
     }
 
     pub(crate) fn resolve_record_pat_field(
@@ -286,7 +289,7 @@ impl SourceAnalyzer {
         let ctx = body::LowerCtx::with_hygiene(db.upcast(), &hygiene);
         let hir_path = Path::from_src(path.clone(), &ctx)?;
 
-        // Case where path is a qualifier of another path, e.g. foo::bar::Baz where we
+        // Case where path is a qualifier of another path, e.g. foo::bar::Baz where we are
         // trying to resolve foo::bar.
         if let Some(outer_path) = parent().and_then(ast::Path::cast) {
             if let Some(qualifier) = outer_path.qualifier() {
@@ -295,6 +298,15 @@ impl SourceAnalyzer {
                 }
             }
         }
+        // Case where path is a qualifier of a use tree, e.g. foo::bar::{Baz, Qux} where we are
+        // trying to resolve foo::bar.
+        if let Some(use_tree) = parent().and_then(ast::UseTree::cast) {
+            if let Some(qualifier) = use_tree.path() {
+                if path == &qualifier && use_tree.coloncolon_token().is_some() {
+                    return resolve_hir_path_qualifier(db, &self.resolver, &hir_path);
+                }
+            }
+        }
 
         resolve_hir_path_(db, &self.resolver, &hir_path, prefer_value_ns)
     }
diff --git a/crates/hir_def/src/attr.rs b/crates/hir_def/src/attr.rs
index 89a1ea770..385ba8c80 100644
--- a/crates/hir_def/src/attr.rs
+++ b/crates/hir_def/src/attr.rs
@@ -105,7 +105,7 @@ impl RawAttrs {
                 Either::Left(attr) => Attr::from_src(db, attr, hygiene, id),
                 Either::Right(comment) => comment.doc_comment().map(|doc| Attr {
                     id,
-                    input: Some(AttrInput::Literal(SmolStr::new(doc))),
+                    input: Some(Interned::new(AttrInput::Literal(SmolStr::new(doc)))),
                     path: Interned::new(ModPath::from(hir_expand::name!(doc))),
                 }),
             })
@@ -151,7 +151,7 @@ impl RawAttrs {
                     return smallvec![attr.clone()];
                 }
 
-                let subtree = match &attr.input {
+                let subtree = match attr.input.as_deref() {
                     Some(AttrInput::TokenTree(it)) => it,
                     _ => return smallvec![attr.clone()],
                 };
@@ -251,7 +251,7 @@ impl Attrs {
     }
 
     pub fn docs(&self) -> Option<Documentation> {
-        let docs = self.by_key("doc").attrs().flat_map(|attr| match attr.input.as_ref()? {
+        let docs = self.by_key("doc").attrs().flat_map(|attr| match attr.input.as_deref()? {
             AttrInput::Literal(s) => Some(s),
             AttrInput::TokenTree(_) => None,
         });
@@ -454,7 +454,7 @@ impl AttrsWithOwner {
         db: &dyn DefDatabase,
     ) -> Option<(Documentation, DocsRangeMap)> {
         // FIXME: code duplication in `docs` above
-        let docs = self.by_key("doc").attrs().flat_map(|attr| match attr.input.as_ref()? {
+        let docs = self.by_key("doc").attrs().flat_map(|attr| match attr.input.as_deref()? {
             AttrInput::Literal(s) => Some((s, attr.id)),
             AttrInput::TokenTree(_) => None,
         });
@@ -637,10 +637,10 @@ pub(crate) struct AttrId {
 pub struct Attr {
     pub(crate) id: AttrId,
     pub(crate) path: Interned<ModPath>,
-    pub(crate) input: Option<AttrInput>,
+    pub(crate) input: Option<Interned<AttrInput>>,
 }
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum AttrInput {
     /// `#[attr = "string"]`
     Literal(SmolStr),
@@ -670,9 +670,9 @@ impl Attr {
                 ast::LiteralKind::String(string) => string.value()?.into(),
                 _ => lit.syntax().first_token()?.text().trim_matches('"').into(),
             };
-            Some(AttrInput::Literal(value))
+            Some(Interned::new(AttrInput::Literal(value)))
         } else if let Some(tt) = ast.token_tree() {
-            Some(AttrInput::TokenTree(ast_to_token_tree(&tt).0))
+            Some(Interned::new(AttrInput::TokenTree(ast_to_token_tree(&tt).0)))
         } else {
             None
         };
@@ -688,7 +688,7 @@ impl Attr {
             return None;
         }
 
-        match &self.input {
+        match self.input.as_deref() {
             Some(AttrInput::TokenTree(args)) => {
                 let mut counter = 0;
                 let paths = args
@@ -720,7 +720,7 @@ impl Attr {
     }
 
     pub fn string_value(&self) -> Option<&SmolStr> {
-        match self.input.as_ref()? {
+        match self.input.as_deref()? {
             AttrInput::Literal(it) => Some(it),
             _ => None,
         }
@@ -735,14 +735,14 @@ pub struct AttrQuery<'a> {
 
 impl<'a> AttrQuery<'a> {
     pub fn tt_values(self) -> impl Iterator<Item = &'a Subtree> {
-        self.attrs().filter_map(|attr| match attr.input.as_ref()? {
+        self.attrs().filter_map(|attr| match attr.input.as_deref()? {
             AttrInput::TokenTree(it) => Some(it),
             _ => None,
         })
     }
 
     pub fn string_value(self) -> Option<&'a SmolStr> {
-        self.attrs().find_map(|attr| match attr.input.as_ref()? {
+        self.attrs().find_map(|attr| match attr.input.as_deref()? {
             AttrInput::Literal(it) => Some(it),
             _ => None,
         })
diff --git a/crates/hir_def/src/data.rs b/crates/hir_def/src/data.rs
index 135a6698e..8bcac60ef 100644
--- a/crates/hir_def/src/data.rs
+++ b/crates/hir_def/src/data.rs
@@ -112,7 +112,7 @@ pub struct TypeAliasData {
     pub visibility: RawVisibility,
     pub is_extern: bool,
     /// Bounds restricting the type alias itself (eg. `type Ty: Bound;` in a trait or impl).
-    pub bounds: Vec<TypeBound>,
+    pub bounds: Vec<Interned<TypeBound>>,
 }
 
 impl TypeAliasData {
@@ -141,7 +141,7 @@ pub struct TraitData {
     pub is_auto: bool,
     pub is_unsafe: bool,
     pub visibility: RawVisibility,
-    pub bounds: Box<[TypeBound]>,
+    pub bounds: Box<[Interned<TypeBound>]>,
 }
 
 impl TraitData {
diff --git a/crates/hir_def/src/generics.rs b/crates/hir_def/src/generics.rs
index de5acced8..44d22b918 100644
--- a/crates/hir_def/src/generics.rs
+++ b/crates/hir_def/src/generics.rs
@@ -68,9 +68,19 @@ pub struct GenericParams {
 /// associated type bindings like `Iterator<Item = u32>`.
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub enum WherePredicate {
-    TypeBound { target: WherePredicateTypeTarget, bound: TypeBound },
-    Lifetime { target: LifetimeRef, bound: LifetimeRef },
-    ForLifetime { lifetimes: Box<[Name]>, target: WherePredicateTypeTarget, bound: TypeBound },
+    TypeBound {
+        target: WherePredicateTypeTarget,
+        bound: Interned<TypeBound>,
+    },
+    Lifetime {
+        target: LifetimeRef,
+        bound: LifetimeRef,
+    },
+    ForLifetime {
+        lifetimes: Box<[Name]>,
+        target: WherePredicateTypeTarget,
+        bound: Interned<TypeBound>,
+    },
 }
 
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
@@ -339,11 +349,11 @@ impl GenericParams {
                 Some(hrtb_lifetimes) => WherePredicate::ForLifetime {
                     lifetimes: hrtb_lifetimes.clone(),
                     target: WherePredicateTypeTarget::TypeRef(Interned::new(type_ref)),
-                    bound,
+                    bound: Interned::new(bound),
                 },
                 None => WherePredicate::TypeBound {
                     target: WherePredicateTypeTarget::TypeRef(Interned::new(type_ref)),
-                    bound,
+                    bound: Interned::new(bound),
                 },
             },
             (Either::Right(lifetime), TypeBound::Lifetime(bound)) => {
diff --git a/crates/hir_def/src/intern.rs b/crates/hir_def/src/intern.rs
index 5cc7f2df6..79ba970e7 100644
--- a/crates/hir_def/src/intern.rs
+++ b/crates/hir_def/src/intern.rs
@@ -216,7 +216,10 @@ pub use crate::_impl_internable as impl_internable;
 impl_internable!(
     crate::type_ref::TypeRef,
     crate::type_ref::TraitRef,
+    crate::type_ref::TypeBound,
     crate::path::ModPath,
+    crate::path::GenericArgs,
+    crate::attr::AttrInput,
     GenericParams,
     str,
 );
diff --git a/crates/hir_def/src/item_tree.rs b/crates/hir_def/src/item_tree.rs
index 528270d49..11767d100 100644
--- a/crates/hir_def/src/item_tree.rs
+++ b/crates/hir_def/src/item_tree.rs
@@ -1,4 +1,34 @@
 //! A simplified AST that only contains items.
+//!
+//! This is the primary IR used throughout `hir_def`. It is the input to the name resolution
+//! algorithm, as well as to the queries defined in `adt.rs`, `data.rs`, and most things in
+//! `attr.rs`.
+//!
+//! `ItemTree`s are built per `HirFileId`, from the syntax tree of the parsed file. This means that
+//! they are crate-independent: they don't know which `#[cfg]`s are active or which module they
+//! belong to, since those concepts don't exist at this level (a single `ItemTree` might be part of
+//! multiple crates, or might be included into the same crate twice via `#[path]`).
+//!
+//! One important purpose of this layer is to provide an "invalidation barrier" for incremental
+//! computations: when typing inside an item body, the `ItemTree` of the modified file is typically
+//! unaffected, so we don't have to recompute name resolution results or item data (see `data.rs`).
+//!
+//! The `ItemTree` for the currently open file can be displayed by using the VS Code command
+//! "Rust Analyzer: Debug ItemTree".
+//!
+//! Compared to rustc's architecture, `ItemTree` has properties from both rustc's AST and HIR: many
+//! syntax-level Rust features are already desugared to simpler forms in the `ItemTree`, but name
+//! resolution has not yet been performed. `ItemTree`s are per-file, while rustc's AST and HIR are
+//! per-crate, because we are interested in incrementally computing it.
+//!
+//! The representation of items in the `ItemTree` should generally mirror the surface syntax: it is
+//! usually a bad idea to desugar a syntax-level construct to something that is structurally
+//! different here. Name resolution needs to be able to process attributes and expand macros
+//! (including attribute macros), and having a 1-to-1 mapping between syntax and the `ItemTree`
+//! avoids introducing subtle bugs.
+//!
+//! In general, any item in the `ItemTree` stores its `AstId`, which allows mapping it back to its
+//! surface syntax.
 
 mod lower;
 mod pretty;
@@ -500,8 +530,8 @@ pub struct Import {
     pub alias: Option<ImportAlias>,
     pub visibility: RawVisibilityId,
     pub is_glob: bool,
-    /// AST ID of the `use` or `extern crate` item this import was derived from. Note that many
-    /// `Import`s can map to the same `use` item.
+    /// AST ID of the `use` item this import was derived from. Note that many `Import`s can map to
+    /// the same `use` item.
     pub ast_id: FileAstId<ast::Use>,
     /// Index of this `Import` when the containing `Use` is visited via `ModPath::expand_use_item`.
     ///
@@ -614,7 +644,7 @@ pub struct Trait {
     pub generic_params: Interned<GenericParams>,
     pub is_auto: bool,
     pub is_unsafe: bool,
-    pub bounds: Box<[TypeBound]>,
+    pub bounds: Box<[Interned<TypeBound>]>,
     pub items: Box<[AssocItem]>,
     pub ast_id: FileAstId<ast::Trait>,
 }
@@ -634,7 +664,7 @@ pub struct TypeAlias {
     pub name: Name,
     pub visibility: RawVisibilityId,
     /// Bounds on the type alias itself. Only valid in trait declarations, eg. `type Assoc: Copy;`.
-    pub bounds: Box<[TypeBound]>,
+    pub bounds: Box<[Interned<TypeBound>]>,
     pub generic_params: Interned<GenericParams>,
     pub type_ref: Option<Interned<TypeRef>>,
     pub is_extern: bool,
diff --git a/crates/hir_def/src/item_tree/lower.rs b/crates/hir_def/src/item_tree/lower.rs
index 91cf75371..b4389371f 100644
--- a/crates/hir_def/src/item_tree/lower.rs
+++ b/crates/hir_def/src/item_tree/lower.rs
@@ -384,7 +384,7 @@ impl<'a> Ctx<'a> {
 
         let ret_type = if func.async_token().is_some() {
             let future_impl = desugar_future_path(ret_type);
-            let ty_bound = TypeBound::Path(future_impl);
+            let ty_bound = Interned::new(TypeBound::Path(future_impl));
             TypeRef::ImplTrait(vec![ty_bound])
         } else {
             ret_type
@@ -738,11 +738,12 @@ impl<'a> Ctx<'a> {
         Interned::new(generics)
     }
 
-    fn lower_type_bounds(&mut self, node: &impl ast::TypeBoundsOwner) -> Vec<TypeBound> {
+    fn lower_type_bounds(&mut self, node: &impl ast::TypeBoundsOwner) -> Vec<Interned<TypeBound>> {
         match node.type_bound_list() {
-            Some(bound_list) => {
-                bound_list.bounds().map(|it| TypeBound::from_ast(&self.body_ctx, it)).collect()
-            }
+            Some(bound_list) => bound_list
+                .bounds()
+                .map(|it| Interned::new(TypeBound::from_ast(&self.body_ctx, it)))
+                .collect(),
             None => Vec::new(),
         }
     }
@@ -810,7 +811,7 @@ fn desugar_future_path(orig: TypeRef) -> Path {
     let binding =
         AssociatedTypeBinding { name: name![Output], type_ref: Some(orig), bounds: Vec::new() };
     last.bindings.push(binding);
-    generic_args.push(Some(Arc::new(last)));
+    generic_args.push(Some(Interned::new(last)));
 
     Path::from_known_path(path, generic_args)
 }
diff --git a/crates/hir_def/src/item_tree/pretty.rs b/crates/hir_def/src/item_tree/pretty.rs
index 4bc87a0e2..9394a5de6 100644
--- a/crates/hir_def/src/item_tree/pretty.rs
+++ b/crates/hir_def/src/item_tree/pretty.rs
@@ -513,13 +513,13 @@ impl<'a> Printer<'a> {
         }
     }
 
-    fn print_type_bounds(&mut self, bounds: &[TypeBound]) {
+    fn print_type_bounds(&mut self, bounds: &[Interned<TypeBound>]) {
         for (i, bound) in bounds.iter().enumerate() {
             if i != 0 {
                 w!(self, " + ");
             }
 
-            match bound {
+            match bound.as_ref() {
                 TypeBound::Path(path) => self.print_path(path),
                 TypeBound::Lifetime(lt) => w!(self, "{}", lt.name),
                 TypeBound::Error => w!(self, "{{unknown}}"),
diff --git a/crates/hir_def/src/lib.rs b/crates/hir_def/src/lib.rs
index a82ea5957..70001cac8 100644
--- a/crates/hir_def/src/lib.rs
+++ b/crates/hir_def/src/lib.rs
@@ -485,6 +485,14 @@ impl VariantId {
             VariantId::UnionId(it) => it.lookup(db).id.file_id(),
         }
     }
+
+    pub fn adt_id(self) -> AdtId {
+        match self {
+            VariantId::EnumVariantId(it) => it.parent.into(),
+            VariantId::StructId(it) => it.into(),
+            VariantId::UnionId(it) => it.into(),
+        }
+    }
 }
 
 trait Intern {
diff --git a/crates/hir_def/src/nameres/collector.rs b/crates/hir_def/src/nameres/collector.rs
index 014ea4de4..2ae740d0e 100644
--- a/crates/hir_def/src/nameres/collector.rs
+++ b/crates/hir_def/src/nameres/collector.rs
@@ -285,7 +285,7 @@ impl DefCollector<'_> {
                 let registered_name = if *attr_name == hir_expand::name![register_attr]
                     || *attr_name == hir_expand::name![register_tool]
                 {
-                    match &attr.input {
+                    match attr.input.as_deref() {
                         Some(AttrInput::TokenTree(subtree)) => match &*subtree.token_trees {
                             [tt::TokenTree::Leaf(tt::Leaf::Ident(name))] => name.as_name(),
                             _ => continue,
diff --git a/crates/hir_def/src/path.rs b/crates/hir_def/src/path.rs
index 9b8873fd2..45ab9d0ff 100644
--- a/crates/hir_def/src/path.rs
+++ b/crates/hir_def/src/path.rs
@@ -4,7 +4,6 @@ mod lower;
 use std::{
     fmt::{self, Display},
     iter,
-    sync::Arc,
 };
 
 use crate::{body::LowerCtx, db::DefDatabase, intern::Interned, type_ref::LifetimeRef};
@@ -136,7 +135,7 @@ pub struct Path {
     type_anchor: Option<Interned<TypeRef>>,
     mod_path: Interned<ModPath>,
     /// Invariant: the same len as `self.mod_path.segments`
-    generic_args: Vec<Option<Arc<GenericArgs>>>,
+    generic_args: Vec<Option<Interned<GenericArgs>>>,
 }
 
 /// Generic arguments to a path segment (e.g. the `i32` in `Option<i32>`). This
@@ -165,7 +164,7 @@ pub struct AssociatedTypeBinding {
     /// Bounds for the associated type, like in `Iterator<Item:
     /// SomeOtherTrait>`. (This is the unstable `associated_type_bounds`
     /// feature.)
-    pub bounds: Vec<TypeBound>,
+    pub bounds: Vec<Interned<TypeBound>>,
 }
 
 /// A single generic argument.
@@ -185,7 +184,7 @@ impl Path {
     /// Converts a known mod path to `Path`.
     pub(crate) fn from_known_path(
         path: ModPath,
-        generic_args: Vec<Option<Arc<GenericArgs>>>,
+        generic_args: Vec<Option<Interned<GenericArgs>>>,
     ) -> Path {
         Path { type_anchor: None, mod_path: Interned::new(path), generic_args }
     }
@@ -239,7 +238,7 @@ pub struct PathSegment<'a> {
 
 pub struct PathSegments<'a> {
     segments: &'a [Name],
-    generic_args: &'a [Option<Arc<GenericArgs>>],
+    generic_args: &'a [Option<Interned<GenericArgs>>],
 }
 
 impl<'a> PathSegments<'a> {
diff --git a/crates/hir_def/src/path/lower.rs b/crates/hir_def/src/path/lower.rs
index a873325b2..5d5dd9c8f 100644
--- a/crates/hir_def/src/path/lower.rs
+++ b/crates/hir_def/src/path/lower.rs
@@ -3,7 +3,6 @@
 mod lower_use;
 
 use crate::intern::Interned;
-use std::sync::Arc;
 
 use either::Either;
 use hir_expand::name::{name, AsName};
@@ -48,7 +47,7 @@ pub(super) fn lower_path(mut path: ast::Path, ctx: &LowerCtx) -> Option<Path> {
                                     segment.ret_type(),
                                 )
                             })
-                            .map(Arc::new);
+                            .map(Interned::new);
                         segments.push(name);
                         generic_args.push(args)
                     }
@@ -87,13 +86,13 @@ pub(super) fn lower_path(mut path: ast::Path, ctx: &LowerCtx) -> Option<Path> {
                         // Insert the type reference (T in the above example) as Self parameter for the trait
                         let last_segment =
                             generic_args.iter_mut().rev().nth(num_segments.saturating_sub(1))?;
-                        if last_segment.is_none() {
-                            *last_segment = Some(Arc::new(GenericArgs::empty()));
+                        let mut args_inner = match last_segment {
+                            Some(it) => it.as_ref().clone(),
+                            None => GenericArgs::empty(),
                         };
-                        let args = last_segment.as_mut().unwrap();
-                        let mut args_inner = Arc::make_mut(args);
                         args_inner.has_self_type = true;
                         args_inner.args.insert(0, GenericArg::Type(self_type));
+                        *last_segment = Some(Interned::new(args_inner));
                     }
                 }
             }
@@ -171,7 +170,9 @@ pub(super) fn lower_generic_args(
                     let name = name_ref.as_name();
                     let type_ref = assoc_type_arg.ty().map(|it| TypeRef::from_ast(lower_ctx, it));
                     let bounds = if let Some(l) = assoc_type_arg.type_bound_list() {
-                        l.bounds().map(|it| TypeBound::from_ast(lower_ctx, it)).collect()
+                        l.bounds()
+                            .map(|it| Interned::new(TypeBound::from_ast(lower_ctx, it)))
+                            .collect()
                     } else {
                         Vec::new()
                     };
diff --git a/crates/hir_def/src/type_ref.rs b/crates/hir_def/src/type_ref.rs
index 9e44547cb..cbde6b940 100644
--- a/crates/hir_def/src/type_ref.rs
+++ b/crates/hir_def/src/type_ref.rs
@@ -5,7 +5,7 @@ use hir_expand::{name::Name, AstId, InFile};
 use std::convert::TryInto;
 use syntax::ast;
 
-use crate::{body::LowerCtx, path::Path};
+use crate::{body::LowerCtx, intern::Interned, path::Path};
 
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 pub enum Mutability {
@@ -72,6 +72,10 @@ impl TraitRef {
 }
 
 /// Compare ty::Ty
+///
+/// Note: Most users of `TypeRef` that end up in the salsa database intern it using
+/// `Interned<TypeRef>` to save space. But notably, nested `TypeRef`s are not interned, since that
+/// does not seem to save any noticeable amount of memory.
 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
 pub enum TypeRef {
     Never,
@@ -87,8 +91,8 @@ pub enum TypeRef {
     /// A fn pointer. Last element of the vector is the return type.
     Fn(Vec<TypeRef>, bool /*varargs*/),
     // For
-    ImplTrait(Vec<TypeBound>),
-    DynTrait(Vec<TypeBound>),
+    ImplTrait(Vec<Interned<TypeBound>>),
+    DynTrait(Vec<Interned<TypeBound>>),
     Macro(AstId<ast::MacroCall>),
     Error,
 }
@@ -228,7 +232,7 @@ impl TypeRef {
                 | TypeRef::Slice(type_ref) => go(&type_ref, f),
                 TypeRef::ImplTrait(bounds) | TypeRef::DynTrait(bounds) => {
                     for bound in bounds {
-                        match bound {
+                        match bound.as_ref() {
                             TypeBound::Path(path) => go_path(path, f),
                             TypeBound::Lifetime(_) | TypeBound::Error => (),
                         }
@@ -258,7 +262,7 @@ impl TypeRef {
                             go(type_ref, f);
                         }
                         for bound in &binding.bounds {
-                            match bound {
+                            match bound.as_ref() {
                                 TypeBound::Path(path) => go_path(path, f),
                                 TypeBound::Lifetime(_) | TypeBound::Error => (),
                             }
@@ -273,9 +277,9 @@ impl TypeRef {
 pub(crate) fn type_bounds_from_ast(
     lower_ctx: &LowerCtx,
     type_bounds_opt: Option<ast::TypeBoundList>,
-) -> Vec<TypeBound> {
+) -> Vec<Interned<TypeBound>> {
     if let Some(type_bounds) = type_bounds_opt {
-        type_bounds.bounds().map(|it| TypeBound::from_ast(lower_ctx, it)).collect()
+        type_bounds.bounds().map(|it| Interned::new(TypeBound::from_ast(lower_ctx, it))).collect()
     } else {
         vec![]
     }
diff --git a/crates/hir_expand/src/db.rs b/crates/hir_expand/src/db.rs
index 5c769c1bf..625c26f0a 100644
--- a/crates/hir_expand/src/db.rs
+++ b/crates/hir_expand/src/db.rs
@@ -131,15 +131,15 @@ pub trait AstDatabase: SourceDatabase {
 /// used for completion, where we want to see what 'would happen' if we insert a
 /// token. The `token_to_map` mapped down into the expansion, with the mapped
 /// token returned.
-pub fn expand_hypothetical(
+pub fn expand_speculative(
     db: &dyn AstDatabase,
     actual_macro_call: MacroCallId,
-    hypothetical_args: &ast::TokenTree,
+    speculative_args: &ast::TokenTree,
     token_to_map: SyntaxToken,
 ) -> Option<(SyntaxNode, SyntaxToken)> {
-    let (tt, tmap_1) = mbe::syntax_node_to_token_tree(hypothetical_args.syntax());
+    let (tt, tmap_1) = mbe::syntax_node_to_token_tree(speculative_args.syntax());
     let range =
-        token_to_map.text_range().checked_sub(hypothetical_args.syntax().text_range().start())?;
+        token_to_map.text_range().checked_sub(speculative_args.syntax().text_range().start())?;
     let token_id = tmap_1.token_by_range(range)?;
 
     let macro_def = {
@@ -147,15 +147,15 @@ pub fn expand_hypothetical(
         db.macro_def(loc.def)?
     };
 
-    let hypothetical_expansion = macro_def.expand(db, actual_macro_call, &tt);
+    let speculative_expansion = macro_def.expand(db, actual_macro_call, &tt);
 
     let fragment_kind = macro_fragment_kind(db, actual_macro_call);
 
     let (node, tmap_2) =
-        mbe::token_tree_to_syntax_node(&hypothetical_expansion.value, fragment_kind).ok()?;
+        mbe::token_tree_to_syntax_node(&speculative_expansion.value, fragment_kind).ok()?;
 
     let token_id = macro_def.map_id_down(token_id);
-    let range = tmap_2.range_by_token(token_id)?.by_kind(token_to_map.kind())?;
+    let range = tmap_2.range_by_token(token_id, token_to_map.kind())?;
     let token = node.syntax_node().covering_element(range).into_token()?;
     Some((node.syntax_node(), token))
 }
@@ -325,7 +325,7 @@ fn macro_expand_with_arg(
     if let Some(eager) = &loc.eager {
         if arg.is_some() {
             return ExpandResult::str_err(
-                "hypothetical macro expansion not implemented for eager macro".to_owned(),
+                "speculative macro expansion not implemented for eager macro".to_owned(),
             );
         } else {
             return ExpandResult {
diff --git a/crates/hir_expand/src/hygiene.rs b/crates/hir_expand/src/hygiene.rs
index 38e09fdd4..d98913907 100644
--- a/crates/hir_expand/src/hygiene.rs
+++ b/crates/hir_expand/src/hygiene.rs
@@ -154,7 +154,7 @@ impl HygieneInfo {
             },
         };
 
-        let range = token_map.range_by_token(token_id)?.by_kind(SyntaxKind::IDENT)?;
+        let range = token_map.range_by_token(token_id, SyntaxKind::IDENT)?;
         Some((tt.with_value(range + tt.value), origin))
     }
 }
diff --git a/crates/hir_expand/src/lib.rs b/crates/hir_expand/src/lib.rs
index 92c679dd2..6be4516a3 100644
--- a/crates/hir_expand/src/lib.rs
+++ b/crates/hir_expand/src/lib.rs
@@ -329,7 +329,7 @@ impl ExpansionInfo {
         let token_id = self.macro_arg.1.token_by_range(range)?;
         let token_id = self.macro_def.map_id_down(token_id);
 
-        let range = self.exp_map.range_by_token(token_id)?.by_kind(token.value.kind())?;
+        let range = self.exp_map.range_by_token(token_id, token.value.kind())?;
 
         let token = self.expanded.value.covering_element(range).into_token()?;
 
@@ -354,7 +354,7 @@ impl ExpansionInfo {
             },
         };
 
-        let range = token_map.range_by_token(token_id)?.by_kind(token.value.kind())?;
+        let range = token_map.range_by_token(token_id, token.value.kind())?;
         let token =
             tt.value.covering_element(range + tt.value.text_range().start()).into_token()?;
         Some((tt.with_value(token), origin))
diff --git a/crates/hir_ty/Cargo.toml b/crates/hir_ty/Cargo.toml
index 66b3418f2..a9994082a 100644
--- a/crates/hir_ty/Cargo.toml
+++ b/crates/hir_ty/Cargo.toml
@@ -18,9 +18,9 @@ ena = "0.14.0"
 log = "0.4.8"
 rustc-hash = "1.1.0"
 scoped-tls = "1"
-chalk-solve = { version = "0.64", default-features = false }
-chalk-ir = "0.64"
-chalk-recursive = "0.64"
+chalk-solve = { version = "0.67", default-features = false }
+chalk-ir = "0.67"
+chalk-recursive = "0.67"
 la-arena = { version = "0.2.0", path = "../../lib/arena" }
 
 stdx = { path = "../stdx", version = "0.0.0" }
diff --git a/crates/hir_ty/src/diagnostics/expr.rs b/crates/hir_ty/src/diagnostics/expr.rs
index 53c4ee9da..d1f113e7f 100644
--- a/crates/hir_ty/src/diagnostics/expr.rs
+++ b/crates/hir_ty/src/diagnostics/expr.rs
@@ -181,7 +181,7 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
         for (id, expr) in body.exprs.iter() {
             if let Expr::MethodCall { receiver, .. } = expr {
                 let function_id = match self.infer.method_resolution(id) {
-                    Some(id) => id,
+                    Some((id, _)) => id,
                     None => continue,
                 };
 
@@ -239,15 +239,11 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
                     return;
                 }
 
-                // FIXME: note that we erase information about substs here. This
-                // is not right, but, luckily, doesn't matter as we care only
-                // about the number of params
-                let callee = match self.infer.method_resolution(call_id) {
-                    Some(callee) => callee,
+                let (callee, subst) = match self.infer.method_resolution(call_id) {
+                    Some(it) => it,
                     None => return,
                 };
-                let sig =
-                    db.callable_item_signature(callee.into()).into_value_and_skipped_binders().0;
+                let sig = db.callable_item_signature(callee.into()).substitute(&Interner, &subst);
 
                 (sig, args)
             }
diff --git a/crates/hir_ty/src/diagnostics/unsafe_check.rs b/crates/hir_ty/src/diagnostics/unsafe_check.rs
index ed97dc0e3..5d13bddea 100644
--- a/crates/hir_ty/src/diagnostics/unsafe_check.rs
+++ b/crates/hir_ty/src/diagnostics/unsafe_check.rs
@@ -105,7 +105,7 @@ fn walk_unsafe(
         Expr::MethodCall { .. } => {
             if infer
                 .method_resolution(current)
-                .map(|func| db.function_data(func).is_unsafe())
+                .map(|(func, _)| db.function_data(func).is_unsafe())
                 .unwrap_or(false)
             {
                 unsafe_exprs.push(UnsafeExpr { expr: current, inside_unsafe_block });
diff --git a/crates/hir_ty/src/display.rs b/crates/hir_ty/src/display.rs
index 7bbd1a1f7..637bbc634 100644
--- a/crates/hir_ty/src/display.rs
+++ b/crates/hir_ty/src/display.rs
@@ -13,6 +13,7 @@ use hir_def::{
     db::DefDatabase,
     find_path,
     generics::TypeParamProvenance,
+    intern::{Internable, Interned},
     item_scope::ItemInNs,
     path::{Path, PathKind},
     type_ref::{TypeBound, TypeRef},
@@ -256,6 +257,12 @@ impl<T: HirDisplay> HirDisplay for &'_ T {
     }
 }
 
+impl<T: HirDisplay + Internable> HirDisplay for Interned<T> {
+    fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
+        HirDisplay::hir_fmt(self.as_ref(), f)
+    }
+}
+
 impl HirDisplay for ProjectionTy {
     fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
         if f.should_truncate() {
diff --git a/crates/hir_ty/src/infer.rs b/crates/hir_ty/src/infer.rs
index f1cebbdb9..db3c937ff 100644
--- a/crates/hir_ty/src/infer.rs
+++ b/crates/hir_ty/src/infer.rs
@@ -37,8 +37,8 @@ use syntax::SmolStr;
 use super::{DomainGoal, InEnvironment, ProjectionTy, TraitEnvironment, TraitRef, Ty};
 use crate::{
     db::HirDatabase, fold_tys, infer::diagnostics::InferenceDiagnostic,
-    lower::ImplTraitLoweringMode, to_assoc_type_id, AliasEq, AliasTy, Goal, Interner, TyBuilder,
-    TyExt, TyKind,
+    lower::ImplTraitLoweringMode, to_assoc_type_id, AliasEq, AliasTy, Goal, Interner, Substitution,
+    TyBuilder, TyExt, TyKind,
 };
 
 // This lint has a false positive here. See the link below for details.
@@ -132,7 +132,7 @@ impl Default for InternedStandardTypes {
 #[derive(Clone, PartialEq, Eq, Debug, Default)]
 pub struct InferenceResult {
     /// For each method call expr, records the function it resolves to.
-    method_resolutions: FxHashMap<ExprId, FunctionId>,
+    method_resolutions: FxHashMap<ExprId, (FunctionId, Substitution)>,
     /// For each field access expr, records the field it resolves to.
     field_resolutions: FxHashMap<ExprId, FieldId>,
     /// For each struct literal or pattern, records the variant it resolves to.
@@ -152,8 +152,8 @@ pub struct InferenceResult {
 }
 
 impl InferenceResult {
-    pub fn method_resolution(&self, expr: ExprId) -> Option<FunctionId> {
-        self.method_resolutions.get(&expr).copied()
+    pub fn method_resolution(&self, expr: ExprId) -> Option<(FunctionId, Substitution)> {
+        self.method_resolutions.get(&expr).cloned()
     }
     pub fn field_resolution(&self, expr: ExprId) -> Option<FieldId> {
         self.field_resolutions.get(&expr).copied()
@@ -284,14 +284,17 @@ impl<'a> InferenceContext<'a> {
         self.table.propagate_diverging_flag();
         let mut result = std::mem::take(&mut self.result);
         for ty in result.type_of_expr.values_mut() {
-            *ty = self.table.resolve_ty_completely(ty.clone());
+            *ty = self.table.resolve_completely(ty.clone());
         }
         for ty in result.type_of_pat.values_mut() {
-            *ty = self.table.resolve_ty_completely(ty.clone());
+            *ty = self.table.resolve_completely(ty.clone());
         }
         for mismatch in result.type_mismatches.values_mut() {
-            mismatch.expected = self.table.resolve_ty_completely(mismatch.expected.clone());
-            mismatch.actual = self.table.resolve_ty_completely(mismatch.actual.clone());
+            mismatch.expected = self.table.resolve_completely(mismatch.expected.clone());
+            mismatch.actual = self.table.resolve_completely(mismatch.actual.clone());
+        }
+        for (_, subst) in result.method_resolutions.values_mut() {
+            *subst = self.table.resolve_completely(subst.clone());
         }
         result
     }
@@ -300,8 +303,8 @@ impl<'a> InferenceContext<'a> {
         self.result.type_of_expr.insert(expr, ty);
     }
 
-    fn write_method_resolution(&mut self, expr: ExprId, func: FunctionId) {
-        self.result.method_resolutions.insert(expr, func);
+    fn write_method_resolution(&mut self, expr: ExprId, func: FunctionId, subst: Substitution) {
+        self.result.method_resolutions.insert(expr, (func, subst));
     }
 
     fn write_field_resolution(&mut self, expr: ExprId, field: FieldId) {
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index 08c05c67c..eab8fac91 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -891,17 +891,21 @@ impl<'a> InferenceContext<'a> {
                 method_name,
             )
         });
-        let (derefed_receiver_ty, method_ty, def_generics) = match resolved {
+        let (derefed_receiver_ty, method_ty, substs) = match resolved {
             Some((ty, func)) => {
                 let ty = canonicalized_receiver.decanonicalize_ty(ty);
-                self.write_method_resolution(tgt_expr, func);
-                (ty, self.db.value_ty(func.into()), Some(generics(self.db.upcast(), func.into())))
+                let generics = generics(self.db.upcast(), func.into());
+                let substs = self.substs_for_method_call(generics, generic_args, &ty);
+                self.write_method_resolution(tgt_expr, func, substs.clone());
+                (ty, self.db.value_ty(func.into()), substs)
             }
-            None => (receiver_ty, Binders::empty(&Interner, self.err_ty()), None),
+            None => (
+                receiver_ty,
+                Binders::empty(&Interner, self.err_ty()),
+                Substitution::empty(&Interner),
+            ),
         };
-        let substs = self.substs_for_method_call(def_generics, generic_args, &derefed_receiver_ty);
         let method_ty = method_ty.substitute(&Interner, &substs);
-        let method_ty = self.insert_type_vars(method_ty);
         self.register_obligations_for_call(&method_ty);
         let (expected_receiver_ty, param_tys, ret_ty) = match method_ty.callable_sig(self.db) {
             Some(sig) => {
@@ -950,23 +954,21 @@ impl<'a> InferenceContext<'a> {
 
     fn substs_for_method_call(
         &mut self,
-        def_generics: Option<Generics>,
+        def_generics: Generics,
         generic_args: Option<&GenericArgs>,
         receiver_ty: &Ty,
     ) -> Substitution {
         let (parent_params, self_params, type_params, impl_trait_params) =
-            def_generics.as_ref().map_or((0, 0, 0, 0), |g| g.provenance_split());
+            def_generics.provenance_split();
         assert_eq!(self_params, 0); // method shouldn't have another Self param
         let total_len = parent_params + type_params + impl_trait_params;
         let mut substs = Vec::with_capacity(total_len);
         // Parent arguments are unknown, except for the receiver type
-        if let Some(parent_generics) = def_generics.as_ref().map(|p| p.iter_parent()) {
-            for (_id, param) in parent_generics {
-                if param.provenance == hir_def::generics::TypeParamProvenance::TraitSelf {
-                    substs.push(receiver_ty.clone());
-                } else {
-                    substs.push(self.err_ty());
-                }
+        for (_id, param) in def_generics.iter_parent() {
+            if param.provenance == hir_def::generics::TypeParamProvenance::TraitSelf {
+                substs.push(receiver_ty.clone());
+            } else {
+                substs.push(self.table.new_type_var());
             }
         }
         // handle provided type arguments
@@ -989,7 +991,7 @@ impl<'a> InferenceContext<'a> {
         };
         let supplied_params = substs.len();
         for _ in supplied_params..total_len {
-            substs.push(self.err_ty());
+            substs.push(self.table.new_type_var());
         }
         assert_eq!(substs.len(), total_len);
         Substitution::from_iter(&Interner, substs)
diff --git a/crates/hir_ty/src/infer/unify.rs b/crates/hir_ty/src/infer/unify.rs
index f8233cac3..ea5684229 100644
--- a/crates/hir_ty/src/infer/unify.rs
+++ b/crates/hir_ty/src/infer/unify.rs
@@ -295,8 +295,11 @@ impl<'a> InferenceTable<'a> {
         .expect("fold failed unexpectedly")
     }
 
-    pub(crate) fn resolve_ty_completely(&mut self, ty: Ty) -> Ty {
-        self.resolve_with_fallback(ty, |_, _, d, _| d)
+    pub(crate) fn resolve_completely<T>(&mut self, t: T) -> T::Result
+    where
+        T: HasInterner<Interner = Interner> + Fold<Interner>,
+    {
+        self.resolve_with_fallback(t, |_, _, d, _| d)
     }
 
     /// Unify two types and register new trait goals that arise from that.
diff --git a/crates/hir_ty/src/lower.rs b/crates/hir_ty/src/lower.rs
index 8a375b973..c83933c73 100644
--- a/crates/hir_ty/src/lower.rs
+++ b/crates/hir_ty/src/lower.rs
@@ -10,6 +10,7 @@ use std::{iter, sync::Arc};
 
 use base_db::CrateId;
 use chalk_ir::{cast::Cast, fold::Shift, interner::HasInterner, Mutability, Safety};
+use hir_def::intern::Interned;
 use hir_def::{
     adt::StructKind,
     body::{Expander, LowerCtx},
@@ -843,7 +844,7 @@ impl<'a> TyLoweringContext<'a> {
             })
     }
 
-    fn lower_impl_trait(&self, bounds: &[TypeBound]) -> ReturnTypeImplTrait {
+    fn lower_impl_trait(&self, bounds: &[Interned<TypeBound>]) -> ReturnTypeImplTrait {
         cov_mark::hit!(lower_rpit);
         let self_ty =
             TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, 0)).intern(&Interner);
@@ -1025,7 +1026,7 @@ pub(crate) fn trait_environment_query(
     };
     if let Some(AssocContainerId::TraitId(trait_id)) = container {
         // add `Self: Trait<T1, T2, ...>` to the environment in trait
-        // function default implementations (and hypothetical code
+        // function default implementations (and speculative code
         // inside consts or type aliases)
         cov_mark::hit!(trait_self_implements_self);
         let substs = TyBuilder::type_params_subst(db, trait_id);
diff --git a/crates/ide/src/doc_links.rs b/crates/ide/src/doc_links.rs
index 320694a17..ec3828ab2 100644
--- a/crates/ide/src/doc_links.rs
+++ b/crates/ide/src/doc_links.rs
@@ -286,7 +286,7 @@ fn get_doc_link(db: &RootDatabase, definition: Definition) -> Option<String> {
         .and_then(
             |url| if let Some(fragment) = fragment { url.join(&fragment).ok() } else { Some(url) },
         )
-        .map(|url| url.into_string())
+        .map(|url| url.into())
 }
 
 fn rewrite_intra_doc_link(
@@ -325,7 +325,7 @@ fn rewrite_intra_doc_link(
         };
     }
 
-    Some((new_url.into_string(), strip_prefixes_suffixes(title).to_string()))
+    Some((new_url.into(), strip_prefixes_suffixes(title).to_string()))
 }
 
 /// Try to resolve path to local documentation via path-based links (i.e. `../gateway/struct.Shard.html`).
@@ -345,7 +345,7 @@ fn rewrite_url_link(db: &RootDatabase, def: ModuleDef, target: &str) -> Option<S
             get_symbol_filename(db, &def).as_deref().map(|f| url.join(f).ok()).flatten()
         })
         .and_then(|url| url.join(target).ok())
-        .map(|url| url.into_string())
+        .map(|url| url.into())
 }
 
 /// Rewrites a markdown document, applying 'callback' to each link.
diff --git a/crates/ide/src/hover.rs b/crates/ide/src/hover.rs
index 9de653739..04598cd06 100644
--- a/crates/ide/src/hover.rs
+++ b/crates/ide/src/hover.rs
@@ -3957,4 +3957,24 @@ mod string {
             "#]],
         )
     }
+
+    #[test]
+    fn function_doesnt_shadow_crate_in_use_tree() {
+        check(
+            r#"
+//- /main.rs crate:main deps:foo
+use foo$0::{foo};
+
+//- /foo.rs crate:foo
+pub fn foo() {}
+"#,
+            expect![[r#"
+                *foo*
+
+                ```rust
+                extern crate foo
+                ```
+            "#]],
+        )
+    }
 }
diff --git a/crates/ide/src/inlay_hints.rs b/crates/ide/src/inlay_hints.rs
index 0ada3f92b..85f887737 100644
--- a/crates/ide/src/inlay_hints.rs
+++ b/crates/ide/src/inlay_hints.rs
@@ -225,8 +225,10 @@ fn hint_iterator(
     }
     let iter_trait = famous_defs.core_iter_Iterator()?;
     let iter_mod = famous_defs.core_iter()?;
-    // assert this struct comes from `core::iter`
+
+    // Assert that this struct comes from `core::iter`.
     iter_mod.visibility_of(db, &strukt.into()).filter(|&vis| vis == hir::Visibility::Public)?;
+
     if ty.impls_trait(db, iter_trait, &[]) {
         let assoc_type_item = iter_trait.items(db).into_iter().find_map(|item| match item {
             hir::AssocItem::TypeAlias(alias) if alias.name(db) == known::Item => Some(alias),
diff --git a/crates/ide_assists/src/handlers/fill_match_arms.rs b/crates/ide_assists/src/handlers/fill_match_arms.rs
index 97435f021..3d2cd739a 100644
--- a/crates/ide_assists/src/handlers/fill_match_arms.rs
+++ b/crates/ide_assists/src/handlers/fill_match_arms.rs
@@ -31,8 +31,8 @@ use crate::{
 //
 // fn handle(action: Action) {
 //     match action {
-//         $0Action::Move { distance } => {}
-//         Action::Stop => {}
+//         $0Action::Move { distance } => todo!(),
+//         Action::Stop => todo!(),
 //     }
 // }
 // ```
@@ -129,7 +129,7 @@ pub(crate) fn fill_match_arms(acc: &mut Assists, ctx: &AssistContext) -> Option<
         |builder| {
             let new_match_arm_list = match_arm_list.clone_for_update();
             let missing_arms = missing_pats
-                .map(|pat| make::match_arm(iter::once(pat), make::expr_empty_block()))
+                .map(|pat| make::match_arm(iter::once(pat), make::ext::expr_todo()))
                 .map(|it| it.clone_for_update());
 
             let catch_all_arm = new_match_arm_list
@@ -350,8 +350,8 @@ fn foo(a: bool) {
             r#"
 fn foo(a: bool) {
     match a {
-        $0true => {}
-        false => {}
+        $0true => todo!(),
+        false => todo!(),
     }
 }
 "#,
@@ -373,7 +373,7 @@ fn foo(a: bool) {
 fn foo(a: bool) {
     match a {
         true => {}
-        $0false => {}
+        $0false => todo!(),
     }
 }
 "#,
@@ -410,10 +410,10 @@ fn foo(a: bool) {
             r#"
 fn foo(a: bool) {
     match (a, a) {
-        $0(true, true) => {}
-        (true, false) => {}
-        (false, true) => {}
-        (false, false) => {}
+        $0(true, true) => todo!(),
+        (true, false) => todo!(),
+        (false, true) => todo!(),
+        (false, false) => todo!(),
     }
 }
 "#,
@@ -435,9 +435,9 @@ fn foo(a: bool) {
 fn foo(a: bool) {
     match (a, a) {
         (false, true) => {}
-        $0(true, true) => {}
-        (true, false) => {}
-        (false, false) => {}
+        $0(true, true) => todo!(),
+        (true, false) => todo!(),
+        (false, false) => todo!(),
     }
 }
 "#,
@@ -471,7 +471,7 @@ fn main() {
     match A::As {
         A::Bs { x, y: Some(_) } => {}
         A::Cs(_, Some(_)) => {}
-        $0A::As => {}
+        $0A::As => todo!(),
     }
 }
 "#,
@@ -499,7 +499,7 @@ use Option::*;
 fn main() {
     match None {
         None => {}
-        Some(${0:_}) => {}
+        Some(${0:_}) => todo!(),
     }
 }
             "#,
@@ -523,7 +523,7 @@ enum A { As, Bs, Cs(Option<i32>) }
 fn main() {
     match A::As {
         A::Cs(_) | A::Bs => {}
-        $0A::As => {}
+        $0A::As => todo!(),
     }
 }
 "#,
@@ -553,8 +553,8 @@ fn main() {
         A::Bs if 0 < 1 => {}
         A::Ds(_value) => { let x = 1; }
         A::Es(B::Xs) => (),
-        $0A::As => {}
-        A::Cs => {}
+        $0A::As => todo!(),
+        A::Cs => todo!(),
     }
 }
 "#,
@@ -580,7 +580,7 @@ fn main() {
     match A::As {
         A::As(_) => {}
         a @ A::Bs(_) => {}
-        A::Cs(${0:_}) => {}
+        A::Cs(${0:_}) => todo!(),
     }
 }
 "#,
@@ -605,11 +605,11 @@ enum A { As, Bs, Cs(String), Ds(String, String), Es { x: usize, y: usize } }
 fn main() {
     let a = A::As;
     match a {
-        $0A::As => {}
-        A::Bs => {}
-        A::Cs(_) => {}
-        A::Ds(_, _) => {}
-        A::Es { x, y } => {}
+        $0A::As => todo!(),
+        A::Bs => todo!(),
+        A::Cs(_) => todo!(),
+        A::Ds(_, _) => todo!(),
+        A::Es { x, y } => todo!(),
     }
 }
 "#,
@@ -638,10 +638,10 @@ fn main() {
     let a = A::One;
     let b = B::One;
     match (a, b) {
-        $0(A::One, B::One) => {}
-        (A::One, B::Two) => {}
-        (A::Two, B::One) => {}
-        (A::Two, B::Two) => {}
+        $0(A::One, B::One) => todo!(),
+        (A::One, B::Two) => todo!(),
+        (A::Two, B::One) => todo!(),
+        (A::Two, B::Two) => todo!(),
     }
 }
 "#,
@@ -670,10 +670,10 @@ fn main() {
     let a = A::One;
     let b = B::One;
     match (&a, &b) {
-        $0(A::One, B::One) => {}
-        (A::One, B::Two) => {}
-        (A::Two, B::One) => {}
-        (A::Two, B::Two) => {}
+        $0(A::One, B::One) => todo!(),
+        (A::One, B::Two) => todo!(),
+        (A::Two, B::One) => todo!(),
+        (A::Two, B::Two) => todo!(),
     }
 }
 "#,
@@ -705,9 +705,9 @@ fn main() {
     let b = B::One;
     match (a, b) {
         (A::Two, B::One) => {}
-        $0(A::One, B::One) => {}
-        (A::One, B::Two) => {}
-        (A::Two, B::Two) => {}
+        $0(A::One, B::One) => todo!(),
+        (A::One, B::Two) => todo!(),
+        (A::Two, B::Two) => todo!(),
     }
 }
 "#,
@@ -736,7 +736,7 @@ fn main() {
     match (a, b) {
         (Some(_), _) => {}
         (None, Some(_)) => {}
-        $0(None, None) => {}
+        $0(None, None) => todo!(),
     }
 }
 "#,
@@ -801,8 +801,8 @@ enum A { One, Two }
 fn main() {
     let a = A::One;
     match (a, ) {
-        $0(A::One,) => {}
-        (A::Two,) => {}
+        $0(A::One,) => todo!(),
+        (A::Two,) => todo!(),
     }
 }
 "#,
@@ -826,7 +826,7 @@ enum A { As }
 
 fn foo(a: &A) {
     match a {
-        $0A::As => {}
+        $0A::As => todo!(),
     }
 }
 "#,
@@ -851,7 +851,7 @@ enum A {
 
 fn foo(a: &mut A) {
     match a {
-        $0A::Es { x, y } => {}
+        $0A::Es { x, y } => todo!(),
     }
 }
 "#,
@@ -891,8 +891,8 @@ enum E { X, Y }
 
 fn main() {
     match E::X {
-        $0E::X => {}
-        E::Y => {}
+        $0E::X => todo!(),
+        E::Y => todo!(),
     }
 }
 "#,
@@ -919,8 +919,8 @@ use foo::E::X;
 
 fn main() {
     match X {
-        $0X => {}
-        foo::E::Y => {}
+        $0X => todo!(),
+        foo::E::Y => todo!(),
     }
 }
 "#,
@@ -947,7 +947,7 @@ fn foo(a: A) {
     match a {
         // foo bar baz
         A::One => {}
-        $0A::Two => {}
+        $0A::Two => todo!(),
         // This is where the rest should be
     }
 }
@@ -971,8 +971,8 @@ fn foo(a: A) {
 enum A { One, Two }
 fn foo(a: A) {
     match a {
-        $0A::One => {}
-        A::Two => {}
+        $0A::One => todo!(),
+        A::Two => todo!(),
         // foo bar baz
     }
 }
@@ -996,8 +996,8 @@ fn foo(a: A) {
 enum A { One, Two, }
 fn foo(a: A) {
     match a {
-        $0A::One => {}
-        A::Two => {}
+        $0A::One => todo!(),
+        A::Two => todo!(),
     }
 }
 "#,
@@ -1021,8 +1021,8 @@ fn foo(opt: Option<i32>) {
             r#"
 fn foo(opt: Option<i32>) {
     match opt {
-        Some(${0:_}) => {}
-        None => {}
+        Some(${0:_}) => todo!(),
+        None => todo!(),
     }
 }
 "#,
@@ -1054,9 +1054,9 @@ enum Test {
 
 fn foo(t: Test) {
     m!(match t {
-    $0Test::A => {}
-    Test::B => {}
-    Test::C => {}
+    $0Test::A => todo!(),
+    Test::B => todo!(),
+    Test::C => todo!(),
 });
 }"#,
         );
@@ -1076,4 +1076,44 @@ fn foo(tuple: (A, A)) {
 "#,
         );
     }
+
+    #[test]
+    fn adds_comma_before_new_arms() {
+        check_assist(
+            fill_match_arms,
+            r#"
+fn foo(t: bool) {
+    match $0t {
+        true => 1 + 2
+    }
+}"#,
+            r#"
+fn foo(t: bool) {
+    match t {
+        true => 1 + 2,
+        $0false => todo!(),
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn does_not_add_extra_comma() {
+        check_assist(
+            fill_match_arms,
+            r#"
+fn foo(t: bool) {
+    match $0t {
+        true => 1 + 2,
+    }
+}"#,
+            r#"
+fn foo(t: bool) {
+    match t {
+        true => 1 + 2,
+        $0false => todo!(),
+    }
+}"#,
+        );
+    }
 }
diff --git a/crates/ide_assists/src/handlers/fix_visibility.rs b/crates/ide_assists/src/handlers/fix_visibility.rs
index 6c7824e55..89f7b2c2c 100644
--- a/crates/ide_assists/src/handlers/fix_visibility.rs
+++ b/crates/ide_assists/src/handlers/fix_visibility.rs
@@ -85,7 +85,7 @@ fn add_vis_to_referenced_module_def(acc: &mut Assists, ctx: &AssistContext) -> O
 
 fn add_vis_to_referenced_record_field(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
     let record_field: ast::RecordExprField = ctx.find_node_at_offset()?;
-    let (record_field_def, _) = ctx.sema.resolve_record_field(&record_field)?;
+    let (record_field_def, _, _) = ctx.sema.resolve_record_field(&record_field)?;
 
     let current_module = ctx.sema.scope(record_field.syntax()).module()?;
     let visibility = record_field_def.visibility(ctx.db());
diff --git a/crates/ide_assists/src/handlers/generate_getter.rs b/crates/ide_assists/src/handlers/generate_getter.rs
index df7d1bb95..09971226e 100644
--- a/crates/ide_assists/src/handlers/generate_getter.rs
+++ b/crates/ide_assists/src/handlers/generate_getter.rs
@@ -23,12 +23,46 @@ use crate::{
 //
 // impl Person {
 //     /// Get a reference to the person's name.
-//     fn name(&self) -> &String {
-//         &self.name
+//     fn $0name(&self) -> &str {
+//         self.name.as_str()
 //     }
 // }
 // ```
 pub(crate) fn generate_getter(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    generate_getter_impl(acc, ctx, false)
+}
+
+// Assist: generate_getter_mut
+//
+// Generate a mut getter method.
+//
+// ```
+// struct Person {
+//     nam$0e: String,
+// }
+// ```
+// ->
+// ```
+// struct Person {
+//     name: String,
+// }
+//
+// impl Person {
+//     /// Get a mutable reference to the person's name.
+//     fn $0name_mut(&mut self) -> &mut String {
+//         &mut self.name
+//     }
+// }
+// ```
+pub(crate) fn generate_getter_mut(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    generate_getter_impl(acc, ctx, true)
+}
+
+pub(crate) fn generate_getter_impl(
+    acc: &mut Assists,
+    ctx: &AssistContext,
+    mutable: bool,
+) -> Option<()> {
     let strukt = ctx.find_node_at_offset::<ast::Struct>()?;
     let field = ctx.find_node_at_offset::<ast::RecordField>()?;
 
@@ -37,39 +71,52 @@ pub(crate) fn generate_getter(acc: &mut Assists, ctx: &AssistContext) -> Option<
     let field_ty = field.ty()?;
 
     // Return early if we've found an existing fn
-    let fn_name = to_lower_snake_case(&field_name.to_string());
+    let mut fn_name = to_lower_snake_case(&field_name.to_string());
+    if mutable {
+        format_to!(fn_name, "_mut");
+    }
     let impl_def = find_struct_impl(&ctx, &ast::Adt::Struct(strukt.clone()), fn_name.as_str())?;
 
+    let (id, label) = if mutable {
+        ("generate_getter_mut", "Generate a mut getter method")
+    } else {
+        ("generate_getter", "Generate a getter method")
+    };
     let target = field.syntax().text_range();
     acc.add_group(
         &GroupLabel("Generate getter/setter".to_owned()),
-        AssistId("generate_getter", AssistKind::Generate),
-        "Generate a getter method",
+        AssistId(id, AssistKind::Generate),
+        label,
         target,
         |builder| {
             let mut buf = String::with_capacity(512);
 
-            let fn_name_spaced = fn_name.replace('_', " ");
-            let strukt_name_spaced =
-                to_lower_snake_case(&strukt_name.to_string()).replace('_', " ");
-
             if impl_def.is_some() {
                 buf.push('\n');
             }
 
             let vis = strukt.visibility().map_or(String::new(), |v| format!("{} ", v));
+            let (ty, body) = if mutable {
+                (format!("&mut {}", field_ty), format!("&mut self.{}", field_name))
+            } else {
+                useless_type_special_case(&field_name.to_string(), &field_ty)
+                    .unwrap_or_else(|| (format!("&{}", field_ty), format!("&self.{}", field_name)))
+            };
+
             format_to!(
                 buf,
-                "    /// Get a reference to the {}'s {}.
-    {}fn {}(&self) -> &{} {{
-        &self.{}
+                "    /// Get a {}reference to the {}'s {}.
+    {}fn {}(&{}self) -> {} {{
+        {}
     }}",
-                strukt_name_spaced,
-                fn_name_spaced,
+                mutable.then(|| "mutable ").unwrap_or_default(),
+                to_lower_snake_case(&strukt_name.to_string()).replace('_', " "),
+                fn_name.trim_end_matches("_mut").replace('_', " "),
                 vis,
                 fn_name,
-                field_ty,
-                fn_name,
+                mutable.then(|| "mut ").unwrap_or_default(),
+                ty,
+                body,
             );
 
             let start_offset = impl_def
@@ -79,56 +126,120 @@ pub(crate) fn generate_getter(acc: &mut Assists, ctx: &AssistContext) -> Option<
                     strukt.syntax().text_range().end()
                 });
 
-            builder.insert(start_offset, buf);
+            match ctx.config.snippet_cap {
+                Some(cap) => {
+                    builder.insert_snippet(cap, start_offset, buf.replacen("fn ", "fn $0", 1))
+                }
+                None => builder.insert(start_offset, buf),
+            }
         },
     )
 }
 
+fn useless_type_special_case(field_name: &str, field_ty: &ast::Type) -> Option<(String, String)> {
+    if field_ty.to_string() == "String" {
+        cov_mark::hit!(useless_type_special_case);
+        return Some(("&str".to_string(), format!("self.{}.as_str()", field_name)));
+    }
+    if let Some(arg) = ty_ctor(field_ty, "Vec") {
+        return Some((format!("&[{}]", arg), format!("self.{}.as_slice()", field_name)));
+    }
+    if let Some(arg) = ty_ctor(field_ty, "Box") {
+        return Some((format!("&{}", arg), format!("self.{}.as_ref()", field_name)));
+    }
+    if let Some(arg) = ty_ctor(field_ty, "Option") {
+        return Some((format!("Option<&{}>", arg), format!("self.{}.as_ref()", field_name)));
+    }
+    None
+}
+
+// FIXME: This should rely on semantic info.
+fn ty_ctor(ty: &ast::Type, ctor: &str) -> Option<String> {
+    let res = ty.to_string().strip_prefix(ctor)?.strip_prefix('<')?.strip_suffix('>')?.to_string();
+    Some(res)
+}
+
 #[cfg(test)]
 mod tests {
     use crate::tests::{check_assist, check_assist_not_applicable};
 
     use super::*;
 
-    fn check_not_applicable(ra_fixture: &str) {
-        check_assist_not_applicable(generate_getter, ra_fixture)
-    }
-
     #[test]
     fn test_generate_getter_from_field() {
         check_assist(
             generate_getter,
             r#"
-struct Context<T: Clone> {
-    dat$0a: T,
-}"#,
+struct Context {
+    dat$0a: Data,
+}
+"#,
             r#"
-struct Context<T: Clone> {
-    data: T,
+struct Context {
+    data: Data,
 }
 
-impl<T: Clone> Context<T> {
+impl Context {
     /// Get a reference to the context's data.
-    fn data(&self) -> &T {
+    fn $0data(&self) -> &Data {
         &self.data
     }
-}"#,
+}
+"#,
+        );
+
+        check_assist(
+            generate_getter_mut,
+            r#"
+struct Context {
+    dat$0a: Data,
+}
+"#,
+            r#"
+struct Context {
+    data: Data,
+}
+
+impl Context {
+    /// Get a mutable reference to the context's data.
+    fn $0data_mut(&mut self) -> &mut Data {
+        &mut self.data
+    }
+}
+"#,
         );
     }
 
     #[test]
     fn test_generate_getter_already_implemented() {
-        check_not_applicable(
+        check_assist_not_applicable(
+            generate_getter,
             r#"
-struct Context<T: Clone> {
-    dat$0a: T,
+struct Context {
+    dat$0a: Data,
 }
 
-impl<T: Clone> Context<T> {
-    fn data(&self) -> &T {
+impl Context {
+    fn data(&self) -> &Data {
         &self.data
     }
-}"#,
+}
+"#,
+        );
+
+        check_assist_not_applicable(
+            generate_getter_mut,
+            r#"
+struct Context {
+    dat$0a: Data,
+}
+
+impl Context {
+    fn data_mut(&mut self) -> &mut Data {
+        &mut self.data
+    }
+}
+"#,
         );
     }
 
@@ -137,20 +248,22 @@ impl<T: Clone> Context<T> {
         check_assist(
             generate_getter,
             r#"
-pub(crate) struct Context<T: Clone> {
-    dat$0a: T,
-}"#,
+pub(crate) struct Context {
+    dat$0a: Data,
+}
+"#,
             r#"
-pub(crate) struct Context<T: Clone> {
-    data: T,
+pub(crate) struct Context {
+    data: Data,
 }
 
-impl<T: Clone> Context<T> {
+impl Context {
     /// Get a reference to the context's data.
-    pub(crate) fn data(&self) -> &T {
+    pub(crate) fn $0data(&self) -> &Data {
         &self.data
     }
-}"#,
+}
+"#,
         );
     }
 
@@ -159,34 +272,105 @@ impl<T: Clone> Context<T> {
         check_assist(
             generate_getter,
             r#"
-struct Context<T: Clone> {
-    data: T,
+struct Context {
+    data: Data,
     cou$0nt: usize,
 }
 
-impl<T: Clone> Context<T> {
+impl Context {
     /// Get a reference to the context's data.
-    fn data(&self) -> &T {
+    fn data(&self) -> &Data {
         &self.data
     }
-}"#,
+}
+"#,
             r#"
-struct Context<T: Clone> {
-    data: T,
+struct Context {
+    data: Data,
     count: usize,
 }
 
-impl<T: Clone> Context<T> {
+impl Context {
     /// Get a reference to the context's data.
-    fn data(&self) -> &T {
+    fn data(&self) -> &Data {
         &self.data
     }
 
     /// Get a reference to the context's count.
-    fn count(&self) -> &usize {
+    fn $0count(&self) -> &usize {
         &self.count
     }
-}"#,
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn test_special_cases() {
+        cov_mark::check!(useless_type_special_case);
+        check_assist(
+            generate_getter,
+            r#"
+struct S { foo: $0String }
+"#,
+            r#"
+struct S { foo: String }
+
+impl S {
+    /// Get a reference to the s's foo.
+    fn $0foo(&self) -> &str {
+        self.foo.as_str()
+    }
+}
+"#,
+        );
+        check_assist(
+            generate_getter,
+            r#"
+struct S { foo: $0Box<Sweets> }
+"#,
+            r#"
+struct S { foo: Box<Sweets> }
+
+impl S {
+    /// Get a reference to the s's foo.
+    fn $0foo(&self) -> &Sweets {
+        self.foo.as_ref()
+    }
+}
+"#,
+        );
+        check_assist(
+            generate_getter,
+            r#"
+struct S { foo: $0Vec<()> }
+"#,
+            r#"
+struct S { foo: Vec<()> }
+
+impl S {
+    /// Get a reference to the s's foo.
+    fn $0foo(&self) -> &[()] {
+        self.foo.as_slice()
+    }
+}
+"#,
+        );
+        check_assist(
+            generate_getter,
+            r#"
+struct S { foo: $0Option<Failure> }
+"#,
+            r#"
+struct S { foo: Option<Failure> }
+
+impl S {
+    /// Get a reference to the s's foo.
+    fn $0foo(&self) -> Option<&Failure> {
+        self.foo.as_ref()
+    }
+}
+"#,
         );
     }
 }
diff --git a/crates/ide_assists/src/handlers/generate_getter_mut.rs b/crates/ide_assists/src/handlers/generate_getter_mut.rs
deleted file mode 100644
index 821c2eed5..000000000
--- a/crates/ide_assists/src/handlers/generate_getter_mut.rs
+++ /dev/null
@@ -1,195 +0,0 @@
-use stdx::{format_to, to_lower_snake_case};
-use syntax::ast::{self, AstNode, NameOwner, VisibilityOwner};
-
-use crate::{
-    utils::{find_impl_block_end, find_struct_impl, generate_impl_text},
-    AssistContext, AssistId, AssistKind, Assists, GroupLabel,
-};
-
-// Assist: generate_getter_mut
-//
-// Generate a mut getter method.
-//
-// ```
-// struct Person {
-//     nam$0e: String,
-// }
-// ```
-// ->
-// ```
-// struct Person {
-//     name: String,
-// }
-//
-// impl Person {
-//     /// Get a mutable reference to the person's name.
-//     fn name_mut(&mut self) -> &mut String {
-//         &mut self.name
-//     }
-// }
-// ```
-pub(crate) fn generate_getter_mut(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
-    let strukt = ctx.find_node_at_offset::<ast::Struct>()?;
-    let field = ctx.find_node_at_offset::<ast::RecordField>()?;
-
-    let strukt_name = strukt.name()?;
-    let field_name = field.name()?;
-    let field_ty = field.ty()?;
-
-    // Return early if we've found an existing fn
-    let fn_name = to_lower_snake_case(&field_name.to_string());
-    let impl_def = find_struct_impl(
-        &ctx,
-        &ast::Adt::Struct(strukt.clone()),
-        format!("{}_mut", fn_name).as_str(),
-    )?;
-
-    let target = field.syntax().text_range();
-    acc.add_group(
-        &GroupLabel("Generate getter/setter".to_owned()),
-        AssistId("generate_getter_mut", AssistKind::Generate),
-        "Generate a mut getter method",
-        target,
-        |builder| {
-            let mut buf = String::with_capacity(512);
-            let fn_name_spaced = fn_name.replace('_', " ");
-            let strukt_name_spaced =
-                to_lower_snake_case(&strukt_name.to_string()).replace('_', " ");
-
-            if impl_def.is_some() {
-                buf.push('\n');
-            }
-
-            let vis = strukt.visibility().map_or(String::new(), |v| format!("{} ", v));
-            format_to!(
-                buf,
-                "    /// Get a mutable reference to the {}'s {}.
-    {}fn {}_mut(&mut self) -> &mut {} {{
-        &mut self.{}
-    }}",
-                strukt_name_spaced,
-                fn_name_spaced,
-                vis,
-                fn_name,
-                field_ty,
-                fn_name,
-            );
-
-            let start_offset = impl_def
-                .and_then(|impl_def| find_impl_block_end(impl_def, &mut buf))
-                .unwrap_or_else(|| {
-                    buf = generate_impl_text(&ast::Adt::Struct(strukt.clone()), &buf);
-                    strukt.syntax().text_range().end()
-                });
-
-            builder.insert(start_offset, buf);
-        },
-    )
-}
-
-#[cfg(test)]
-mod tests {
-    use crate::tests::{check_assist, check_assist_not_applicable};
-
-    use super::*;
-
-    fn check_not_applicable(ra_fixture: &str) {
-        check_assist_not_applicable(generate_getter_mut, ra_fixture)
-    }
-
-    #[test]
-    fn test_generate_getter_mut_from_field() {
-        check_assist(
-            generate_getter_mut,
-            r#"
-struct Context<T: Clone> {
-    dat$0a: T,
-}"#,
-            r#"
-struct Context<T: Clone> {
-    data: T,
-}
-
-impl<T: Clone> Context<T> {
-    /// Get a mutable reference to the context's data.
-    fn data_mut(&mut self) -> &mut T {
-        &mut self.data
-    }
-}"#,
-        );
-    }
-
-    #[test]
-    fn test_generate_getter_mut_already_implemented() {
-        check_not_applicable(
-            r#"
-struct Context<T: Clone> {
-    dat$0a: T,
-}
-
-impl<T: Clone> Context<T> {
-    fn data_mut(&mut self) -> &mut T {
-        &mut self.data
-    }
-}"#,
-        );
-    }
-
-    #[test]
-    fn test_generate_getter_mut_from_field_with_visibility_marker() {
-        check_assist(
-            generate_getter_mut,
-            r#"
-pub(crate) struct Context<T: Clone> {
-    dat$0a: T,
-}"#,
-            r#"
-pub(crate) struct Context<T: Clone> {
-    data: T,
-}
-
-impl<T: Clone> Context<T> {
-    /// Get a mutable reference to the context's data.
-    pub(crate) fn data_mut(&mut self) -> &mut T {
-        &mut self.data
-    }
-}"#,
-        );
-    }
-
-    #[test]
-    fn test_multiple_generate_getter_mut() {
-        check_assist(
-            generate_getter_mut,
-            r#"
-struct Context<T: Clone> {
-    data: T,
-    cou$0nt: usize,
-}
-
-impl<T: Clone> Context<T> {
-    /// Get a mutable reference to the context's data.
-    fn data_mut(&mut self) -> &mut T {
-        &mut self.data
-    }
-}"#,
-            r#"
-struct Context<T: Clone> {
-    data: T,
-    count: usize,
-}
-
-impl<T: Clone> Context<T> {
-    /// Get a mutable reference to the context's data.
-    fn data_mut(&mut self) -> &mut T {
-        &mut self.data
-    }
-
-    /// Get a mutable reference to the context's count.
-    fn count_mut(&mut self) -> &mut usize {
-        &mut self.count
-    }
-}"#,
-        );
-    }
-}
diff --git a/crates/ide_assists/src/lib.rs b/crates/ide_assists/src/lib.rs
index 05644b6ff..16af72927 100644
--- a/crates/ide_assists/src/lib.rs
+++ b/crates/ide_assists/src/lib.rs
@@ -20,8 +20,7 @@ pub mod path_transform;
 use std::str::FromStr;
 
 use hir::Semantics;
-use ide_db::base_db::FileRange;
-use ide_db::{label::Label, source_change::SourceChange, RootDatabase};
+use ide_db::{base_db::FileRange, label::Label, source_change::SourceChange, RootDatabase};
 use syntax::TextRange;
 
 pub(crate) use crate::assist_context::{AssistContext, Assists};
@@ -207,7 +206,6 @@ mod handlers {
     mod generate_enum_projection_method;
     mod generate_from_impl_for_enum;
     mod generate_function;
-    mod generate_getter_mut;
     mod generate_getter;
     mod generate_impl;
     mod generate_new;
@@ -277,8 +275,8 @@ mod handlers {
             generate_enum_projection_method::generate_enum_try_into_method,
             generate_from_impl_for_enum::generate_from_impl_for_enum,
             generate_function::generate_function,
-            generate_getter_mut::generate_getter_mut,
             generate_getter::generate_getter,
+            generate_getter::generate_getter_mut,
             generate_impl::generate_impl,
             generate_new::generate_new,
             generate_setter::generate_setter,
diff --git a/crates/ide_assists/src/tests.rs b/crates/ide_assists/src/tests.rs
index 6a9231e07..2b7c2d581 100644
--- a/crates/ide_assists/src/tests.rs
+++ b/crates/ide_assists/src/tests.rs
@@ -215,8 +215,8 @@ fn assist_order_field_struct() {
 
     assert_eq!(assists.next().expect("expected assist").label, "Change visibility to pub(crate)");
     assert_eq!(assists.next().expect("expected assist").label, "Generate `Deref` impl using `bar`");
-    assert_eq!(assists.next().expect("expected assist").label, "Generate a mut getter method");
     assert_eq!(assists.next().expect("expected assist").label, "Generate a getter method");
+    assert_eq!(assists.next().expect("expected assist").label, "Generate a mut getter method");
     assert_eq!(assists.next().expect("expected assist").label, "Generate a setter method");
     assert_eq!(assists.next().expect("expected assist").label, "Add `#[derive]`");
 }
diff --git a/crates/ide_assists/src/tests/generated.rs b/crates/ide_assists/src/tests/generated.rs
index 4406406a2..de5d9e55a 100644
--- a/crates/ide_assists/src/tests/generated.rs
+++ b/crates/ide_assists/src/tests/generated.rs
@@ -455,8 +455,8 @@ enum Action { Move { distance: u32 }, Stop }
 
 fn handle(action: Action) {
     match action {
-        $0Action::Move { distance } => {}
-        Action::Stop => {}
+        $0Action::Move { distance } => todo!(),
+        Action::Stop => todo!(),
     }
 }
 "#####,
@@ -786,8 +786,8 @@ struct Person {
 
 impl Person {
     /// Get a reference to the person's name.
-    fn name(&self) -> &String {
-        &self.name
+    fn $0name(&self) -> &str {
+        self.name.as_str()
     }
 }
 "#####,
@@ -810,7 +810,7 @@ struct Person {
 
 impl Person {
     /// Get a mutable reference to the person's name.
-    fn name_mut(&mut self) -> &mut String {
+    fn $0name_mut(&mut self) -> &mut String {
         &mut self.name
     }
 }
diff --git a/crates/ide_completion/src/context.rs b/crates/ide_completion/src/context.rs
index 787eb2fd3..2f3fb1710 100644
--- a/crates/ide_completion/src/context.rs
+++ b/crates/ide_completion/src/context.rs
@@ -196,46 +196,46 @@ impl<'a> CompletionContext<'a> {
         };
 
         let mut original_file = original_file.syntax().clone();
-        let mut hypothetical_file = file_with_fake_ident.syntax().clone();
+        let mut speculative_file = file_with_fake_ident.syntax().clone();
         let mut offset = position.offset;
         let mut fake_ident_token = fake_ident_token;
 
         // Are we inside a macro call?
         while let (Some(actual_macro_call), Some(macro_call_with_fake_ident)) = (
             find_node_at_offset::<ast::MacroCall>(&original_file, offset),
-            find_node_at_offset::<ast::MacroCall>(&hypothetical_file, offset),
+            find_node_at_offset::<ast::MacroCall>(&speculative_file, offset),
         ) {
             if actual_macro_call.path().as_ref().map(|s| s.syntax().text())
                 != macro_call_with_fake_ident.path().as_ref().map(|s| s.syntax().text())
             {
                 break;
             }
-            let hypothetical_args = match macro_call_with_fake_ident.token_tree() {
+            let speculative_args = match macro_call_with_fake_ident.token_tree() {
                 Some(tt) => tt,
                 None => break,
             };
-            if let (Some(actual_expansion), Some(hypothetical_expansion)) = (
+            if let (Some(actual_expansion), Some(speculative_expansion)) = (
                 ctx.sema.expand(&actual_macro_call),
                 ctx.sema.speculative_expand(
                     &actual_macro_call,
-                    &hypothetical_args,
+                    &speculative_args,
                     fake_ident_token,
                 ),
             ) {
-                let new_offset = hypothetical_expansion.1.text_range().start();
+                let new_offset = speculative_expansion.1.text_range().start();
                 if new_offset > actual_expansion.text_range().end() {
                     break;
                 }
                 original_file = actual_expansion;
-                hypothetical_file = hypothetical_expansion.0;
-                fake_ident_token = hypothetical_expansion.1;
+                speculative_file = speculative_expansion.0;
+                fake_ident_token = speculative_expansion.1;
                 offset = new_offset;
             } else {
                 break;
             }
         }
-        ctx.fill_keyword_patterns(&hypothetical_file, offset);
-        ctx.fill(&original_file, hypothetical_file, offset);
+        ctx.fill_keyword_patterns(&speculative_file, offset);
+        ctx.fill(&original_file, speculative_file, offset);
         Some(ctx)
     }
 
@@ -337,25 +337,24 @@ impl<'a> CompletionContext<'a> {
                     },
                     ast::RecordExprFieldList(_it) => {
                         cov_mark::hit!(expected_type_struct_field_without_leading_char);
-                        self.token.prev_sibling_or_token()
-                            .and_then(|se| se.into_node())
-                            .and_then(|node| ast::RecordExprField::cast(node))
-                            .and_then(|rf| self.sema.resolve_record_field(&rf).zip(Some(rf)))
-                            .map(|(f, rf)|(
-                                Some(f.0.ty(self.db)),
-                                rf.field_name().map(NameOrNameRef::NameRef),
+                        // wouldn't try {} be nice...
+                        (|| {
+                            let expr_field = self.token.prev_sibling_or_token()?
+                                      .into_node()
+                                      .and_then(|node| ast::RecordExprField::cast(node))?;
+                            let (_, _, ty) = self.sema.resolve_record_field(&expr_field)?;
+                            Some((
+                                Some(ty),
+                                expr_field.field_name().map(NameOrNameRef::NameRef),
                             ))
-                            .unwrap_or((None, None))
+                        })().unwrap_or((None, None))
                     },
                     ast::RecordExprField(it) => {
                         cov_mark::hit!(expected_type_struct_field_with_leading_char);
-                        self.sema
-                            .resolve_record_field(&it)
-                            .map(|f|(
-                                Some(f.0.ty(self.db)),
-                                it.field_name().map(NameOrNameRef::NameRef),
-                            ))
-                            .unwrap_or((None, None))
+                        (
+                            it.expr().as_ref().and_then(|e| self.sema.type_of_expr(e)),
+                            it.field_name().map(NameOrNameRef::NameRef),
+                        )
                     },
                     ast::MatchExpr(it) => {
                         cov_mark::hit!(expected_type_match_arm_without_leading_char);
@@ -382,6 +381,12 @@ impl<'a> CompletionContext<'a> {
                         let def = self.sema.to_def(&it);
                         (def.map(|def| def.ret_type(self.db)), None)
                     },
+                    ast::ClosureExpr(it) => {
+                        let ty = self.sema.type_of_expr(&it.into());
+                        ty.and_then(|ty| ty.as_callable(self.db))
+                            .map(|c| (Some(c.return_type()), None))
+                            .unwrap_or((None, None))
+                    },
                     ast::Stmt(_it) => (None, None),
                     _ => {
                         match node.parent() {
@@ -785,6 +790,19 @@ fn foo() {
     }
 
     #[test]
+    fn expected_type_generic_struct_field() {
+        check_expected_type_and_name(
+            r#"
+struct Foo<T> { a: T }
+fn foo() -> Foo<u32> {
+    Foo { a: $0 }
+}
+"#,
+            expect![[r#"ty: u32, name: a"#]],
+        )
+    }
+
+    #[test]
     fn expected_type_struct_field_with_leading_char() {
         cov_mark::check!(expected_type_struct_field_with_leading_char);
         check_expected_type_and_name(
@@ -895,4 +913,52 @@ fn foo() -> u32 {
             expect![[r#"ty: u32, name: ?"#]],
         )
     }
+
+    #[test]
+    fn expected_type_closure_param_return() {
+        // FIXME: make this work with `|| $0`
+        check_expected_type_and_name(
+            r#"
+fn foo() {
+    bar(|| a$0);
+}
+
+fn bar(f: impl FnOnce() -> u32) {}
+#[lang = "fn_once"]
+trait FnOnce { type Output; }
+"#,
+            expect![[r#"ty: u32, name: ?"#]],
+        );
+    }
+
+    #[test]
+    fn expected_type_generic_function() {
+        check_expected_type_and_name(
+            r#"
+fn foo() {
+    bar::<u32>($0);
+}
+
+fn bar<T>(t: T) {}
+"#,
+            expect![[r#"ty: u32, name: t"#]],
+        );
+    }
+
+    #[test]
+    fn expected_type_generic_method() {
+        check_expected_type_and_name(
+            r#"
+fn foo() {
+    S(1u32).bar($0);
+}
+
+struct S<T>(T);
+impl<T> S<T> {
+    fn bar(self, t: T) {}
+}
+"#,
+            expect![[r#"ty: u32, name: t"#]],
+        );
+    }
 }
diff --git a/crates/ide_completion/src/lib.rs b/crates/ide_completion/src/lib.rs
index 645349215..1152a9850 100644
--- a/crates/ide_completion/src/lib.rs
+++ b/crates/ide_completion/src/lib.rs
@@ -107,7 +107,7 @@ pub use crate::{
 /// identifier prefix/fuzzy match should be done higher in the stack, together
 /// with ordering of completions (currently this is done by the client).
 ///
-/// # Hypothetical Completion Problem
+/// # Speculative Completion Problem
 ///
 /// There's a curious unsolved problem in the current implementation. Often, you
 /// want to compute completions on a *slightly different* text document.
@@ -121,7 +121,7 @@ pub use crate::{
 /// doesn't allow such "phantom" inputs.
 ///
 /// Another case where this would be instrumental is macro expansion. We want to
-/// insert a fake ident and re-expand code. There's `expand_hypothetical` as a
+/// insert a fake ident and re-expand code. There's `expand_speculative` as a
 /// work-around for this.
 ///
 /// A different use-case is completion of injection (examples and links in doc
diff --git a/crates/ide_completion/src/render.rs b/crates/ide_completion/src/render.rs
index 6b04ee164..d7f96b864 100644
--- a/crates/ide_completion/src/render.rs
+++ b/crates/ide_completion/src/render.rs
@@ -667,6 +667,13 @@ fn foo() { A { the$0 } }
                         ),
                         detail: "u32",
                         deprecated: true,
+                        relevance: CompletionRelevance {
+                            exact_name_match: false,
+                            type_match: Some(
+                                CouldUnify,
+                            ),
+                            is_local: false,
+                        },
                     },
                 ]
             "#]],
diff --git a/crates/ide_db/src/call_info/tests.rs b/crates/ide_db/src/call_info/tests.rs
index be1cc12de..1aeda08e5 100644
--- a/crates/ide_db/src/call_info/tests.rs
+++ b/crates/ide_db/src/call_info/tests.rs
@@ -189,6 +189,24 @@ fn main() { S.foo($0); }
 }
 
 #[test]
+fn test_fn_signature_for_generic_method() {
+    check(
+        r#"
+struct S<T>(T);
+impl<T> S<T> {
+    fn foo(&self, x: T) {}
+}
+
+fn main() { S(1u32).foo($0); }
+"#,
+        expect![[r#"
+                fn foo(&self, x: u32)
+                (<x: u32>)
+            "#]],
+    );
+}
+
+#[test]
 fn test_fn_signature_for_method_with_arg_as_assoc_fn() {
     check(
         r#"
diff --git a/crates/ide_db/src/defs.rs b/crates/ide_db/src/defs.rs
index de0dc2a40..1dcccbb8b 100644
--- a/crates/ide_db/src/defs.rs
+++ b/crates/ide_db/src/defs.rs
@@ -311,7 +311,7 @@ impl NameRefClass {
         }
 
         if let Some(record_field) = ast::RecordExprField::for_field_name(name_ref) {
-            if let Some((field, local)) = sema.resolve_record_field(&record_field) {
+            if let Some((field, local, _)) = sema.resolve_record_field(&record_field) {
                 let field = Definition::Field(field);
                 let res = match local {
                     None => NameRefClass::Definition(field),
diff --git a/crates/ide_db/src/ty_filter.rs b/crates/ide_db/src/ty_filter.rs
index 00678bf3e..766d8c628 100644
--- a/crates/ide_db/src/ty_filter.rs
+++ b/crates/ide_db/src/ty_filter.rs
@@ -4,7 +4,7 @@
 
 use std::iter;
 
-use hir::{Adt, Semantics, Type};
+use hir::Semantics;
 use syntax::ast::{self, make};
 
 use crate::RootDatabase;
@@ -20,9 +20,9 @@ impl TryEnum {
     const ALL: [TryEnum; 2] = [TryEnum::Option, TryEnum::Result];
 
     /// Returns `Some(..)` if the provided type is an enum that implements `std::ops::Try`.
-    pub fn from_ty(sema: &Semantics<RootDatabase>, ty: &Type) -> Option<TryEnum> {
+    pub fn from_ty(sema: &Semantics<RootDatabase>, ty: &hir::Type) -> Option<TryEnum> {
         let enum_ = match ty.as_adt() {
-            Some(Adt::Enum(it)) => it,
+            Some(hir::Adt::Enum(it)) => it,
             _ => return None,
         };
         TryEnum::ALL.iter().find_map(|&var| {
diff --git a/crates/mbe/src/lib.rs b/crates/mbe/src/lib.rs
index 3af5bc18b..b95374b76 100644
--- a/crates/mbe/src/lib.rs
+++ b/crates/mbe/src/lib.rs
@@ -14,6 +14,7 @@ mod tests;
 
 #[cfg(test)]
 mod benchmark;
+mod token_map;
 
 use std::fmt;
 
@@ -63,9 +64,12 @@ impl fmt::Display for ExpandError {
     }
 }
 
-pub use crate::syntax_bridge::{
-    ast_to_token_tree, parse_exprs_with_sep, parse_to_token_tree, syntax_node_to_token_tree,
-    token_tree_to_syntax_node, TokenMap,
+pub use crate::{
+    syntax_bridge::{
+        ast_to_token_tree, parse_exprs_with_sep, parse_to_token_tree, syntax_node_to_token_tree,
+        token_tree_to_syntax_node,
+    },
+    token_map::TokenMap,
 };
 
 /// This struct contains AST for a single `macro_rules` definition. What might
diff --git a/crates/mbe/src/syntax_bridge.rs b/crates/mbe/src/syntax_bridge.rs
index b13168bd3..b11172caf 100644
--- a/crates/mbe/src/syntax_bridge.rs
+++ b/crates/mbe/src/syntax_bridge.rs
@@ -10,36 +10,8 @@ use syntax::{
 };
 use tt::buffer::{Cursor, TokenBuffer};
 
-use crate::ExpandError;
 use crate::{subtree_source::SubtreeTokenSource, tt_iter::TtIter};
-
-#[derive(Debug, PartialEq, Eq, Clone, Copy)]
-pub enum TokenTextRange {
-    Token(TextRange),
-    Delimiter(TextRange),
-}
-
-impl TokenTextRange {
-    pub fn by_kind(self, kind: SyntaxKind) -> Option<TextRange> {
+use crate::{ExpandError, TokenMap};