54 files changed, 1489 insertions, 801 deletions

diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 0f68b234c..63518e67f 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -42,14 +42,6 @@ jobs:
       if: matrix.os == 'windows-latest'
       run: Rename-Item C:\Users\runneradmin\.rustup\toolchains\stable-x86_64-pc-windows-msvc C:\Users\runneradmin\.rustup\toolchains\stable-x86_64-pc-windows-msvc.old
 
-    # Work around https://github.com/actions/cache/issues/403 by using GNU tar
-    # instead of BSD tar.
-    - name: Install GNU tar
-      if: matrix.os == 'macos-latest'
-      run: |
-        brew install gnu-tar
-        echo PATH="/usr/local/opt/gnu-tar/libexec/gnubin:$PATH" >> $GITHUB_ENV
-
     - name: Install Rust toolchain
       uses: actions-rs/toolchain@v1
       with:
@@ -58,19 +50,8 @@ jobs:
         override: true
         components: rustfmt, rust-src
 
-    - name: Cache cargo directories
-      uses: actions/cache@v2
-      with:
-        path: |
-          ~/.cargo/registry
-          ~/.cargo/git
-        key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
-
-    - name: Cache cargo target dir
-      uses: actions/cache@v2
-      with:
-        path: target
-        key: ${{ runner.os }}-cargo-build-target-${{ hashFiles('**/Cargo.lock') }}
+    - name: Cache Dependencies
+      uses: Swatinem/rust-cache@ce325b60658c1b38465c06cc965b79baf32c1e72
 
     - name: Compile
       run: cargo test --no-run --locked
@@ -78,9 +59,6 @@ jobs:
     - name: Test
       run: cargo test -- --nocapture
 
-    - name: Prepare cache
-      run: cargo xtask pre-cache
-
   # Weird targets to catch non-portable code
   rust-cross:
     name: Rust Cross
@@ -103,13 +81,8 @@ jobs:
     - name: Install Rust targets
       run: rustup target add ${{ env.targets }}
 
-    - name: Cache cargo directories
-      uses: actions/cache@v2
-      with:
-        path: |
-          ~/.cargo/registry
-          ~/.cargo/git
-        key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+    - name: Cache Dependencies
+      uses: Swatinem/rust-cache@ce325b60658c1b38465c06cc965b79baf32c1e72
 
     - name: Check
       run: |
diff --git a/Cargo.lock b/Cargo.lock
index ba6862e98..c411ce8e6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -72,11 +72,12 @@ checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
 
 [[package]]
 name = "backtrace"
-version = "0.3.57"
+version = "0.3.58"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "78ed203b9ba68b242c62b3fb7480f589dd49829be1edb3fe8fc8b4ffda2dcb8d"
+checksum = "88fb5a785d6b44fd9d6700935608639af1b8356de1e55d5f7c2740f4faa15d82"
 dependencies = [
  "addr2line",
+ "cc",
  "cfg-if",
  "libc",
  "miniz_oxide",
@@ -280,9 +281,9 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-epoch"
-version = "0.9.3"
+version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2584f639eb95fea8c798496315b297cf81b9b58b6d30ab066a75455333cf4b12"
+checksum = "52fb27eab85b17fbb9f6fd667089e07d6a2eb8743d02639ee7f6a7a7729c9c94"
 dependencies = [
  "cfg-if",
  "crossbeam-utils",
@@ -293,9 +294,9 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-utils"
-version = "0.8.3"
+version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e7e9d99fa91428effe99c5c6d4634cdeba32b8cf784fc428a2a687f61a952c49"
+checksum = "4feb231f0d4d6af81aed15928e58ecf5816aa62a2393e2c82f46973e92a9a278"
 dependencies = [
  "autocfg",
  "cfg-if",
@@ -798,9 +799,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.93"
+version = "0.2.94"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9385f66bf6105b241aa65a61cb923ef20efc665cb9f9bb50ac2f0c4b7f378d41"
+checksum = "18794a8ad5b29321f790b55d93dfba91e125cb1a9edbd4f8e3150acc771c1a5e"
 
 [[package]]
 name = "libloading"
@@ -823,9 +824,9 @@ dependencies = [
 
 [[package]]
 name = "lock_api"
-version = "0.4.3"
+version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5a3c91c24eae6777794bb1997ad98bbb87daf92890acab859f7eaa4320333176"
+checksum = "0382880606dff6d15c9476c416d18690b72742aa7b605bb6dd6ec9030fbf07eb"
 dependencies = [
  "scopeguard",
 ]
@@ -897,19 +898,9 @@ dependencies = [
 
 [[package]]
 name = "memchr"
-version = "2.3.4"
+version = "2.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ee1c47aaa256ecabcaea351eae4a9b01ef39ed810004e298d2511ed284b1525"
-
-[[package]]
-name = "memmap"
-version = "0.7.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6585fd95e7bb50d6cc31e20d4cf9afb4e2ba16c5846fc76793f11218da9c475b"
-dependencies = [
- "libc",
- "winapi",
-]
+checksum = "b16bd47d9e329435e309c58469fe0791c2d0d1ba96ec0954152a5ae2b04387dc"
 
 [[package]]
 name = "memmap2"
@@ -1108,9 +1099,9 @@ checksum = "d4fd5641d01c8f18a23da7b6fe29298ff4b55afcccdf78973b24cf3175fee32e"
 
 [[package]]
 name = "perf-event"
-version = "0.4.6"
+version = "0.4.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b7a1c2678a77d65edf773bd900f5b87f0944ac3421949842a2c6a4efe42d6c66"
+checksum = "5396562cd2eaa828445d6d34258ae21ee1eb9d40fe626ca7f51c8dccb4af9d66"
 dependencies = [
  "libc",
  "perf-event-open-sys",
@@ -1173,7 +1164,7 @@ dependencies = [
  "crossbeam-channel",
  "jod-thread",
  "log",
- "memmap",
+ "memmap2",
  "object",
  "profile",
  "serde",
@@ -1294,18 +1285,18 @@ dependencies = [
 
 [[package]]
 name = "redox_syscall"
-version = "0.2.6"
+version = "0.2.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8270314b5ccceb518e7e578952f0b72b88222d02e8f77f5ecf7abbb673539041"
+checksum = "85dd92e586f7355c633911e11f77f3d12f04b1b1bd76a198bd34ae3af8341ef2"
 dependencies = [
  "bitflags",
 ]
 
 [[package]]
 name = "regex"
-version = "1.4.6"
+version = "1.5.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2a26af418b574bd56588335b3a3659a65725d4e636eb1016c2f9e3b38c7cc759"
+checksum = "ce5f1ceb7f74abbce32601642fcf8e8508a8a8991e0621c7d750295b9095702b"
 dependencies = [
  "regex-syntax",
 ]
@@ -1322,9 +1313,9 @@ dependencies = [
 
 [[package]]
 name = "regex-syntax"
-version = "0.6.23"
+version = "0.6.25"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "24d5f089152e60f62d28b835fbff2cd2e8dc0baf1ac13343bef92ab7eed84548"
+checksum = "f497285884f3fcff424ffc933e56d7cbca511def0c9831a7f9b5f6153e3cc89b"
 
 [[package]]
 name = "rowan"
@@ -1420,9 +1411,9 @@ checksum = "71d301d4193d031abdd79ff7e3dd721168a9572ef3fe51a1517aba235bd8f86e"
 
 [[package]]
 name = "salsa"
-version = "0.16.0"
+version = "0.16.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d8fadca2ab5de17acf66d744f4888049ca8f1bb9b8a1ab8afd9d032cc959c5dc"
+checksum = "4b84d9f96071f3f3be0dc818eae3327625d8ebc95b58da37d6850724f31d3403"
 dependencies = [
  "crossbeam-utils",
  "indexmap",
@@ -1565,9 +1556,9 @@ dependencies = [
 
 [[package]]
 name = "snap"
-version = "1.0.4"
+version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc725476a1398f0480d56cd0ad381f6f32acf2642704456f8f59a35df464b59a"
+checksum = "45456094d1983e2ee2a18fdfebce3189fa451699d0502cb8e3b49dba5ba41451"
 
 [[package]]
 name = "stdx"
@@ -1582,9 +1573,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.70"
+version = "1.0.71"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b9505f307c872bab8eb46f77ae357c8eba1fdacead58ee5a850116b1d7f82883"
+checksum = "ad184cc9470f9117b2ac6817bfe297307418819ba40552f9b3846f05c33d5373"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1702,9 +1693,9 @@ dependencies = [
 
 [[package]]
 name = "tracing"
-version = "0.1.25"
+version = "0.1.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "01ebdc2bb4498ab1ab5f5b73c5803825e60199229ccba0698170e3be0e7f959f"
+checksum = "09adeb8c97449311ccd28a427f96fb563e7fd31aabf994189879d9da2394b89d"
 dependencies = [
  "cfg-if",
  "pin-project-lite",
@@ -1725,9 +1716,9 @@ dependencies = [
 
 [[package]]
 name = "tracing-core"
-version = "0.1.17"
+version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f50de3927f93d202783f4513cda820ab47ef17f624b03c096e86ef00c67e6b5f"
+checksum = "a9ff14f98b1a4b289c6248a023c1c2fa1491062964e9fed67ab29c4e4da4a052"
 dependencies = [
  "lazy_static",
 ]
@@ -1755,9 +1746,9 @@ dependencies = [
 
 [[package]]
 name = "tracing-subscriber"
-version = "0.2.17"
+version = "0.2.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "705096c6f83bf68ea5d357a6aa01829ddbdac531b357b45abeca842938085baa"
+checksum = "aa5553bf0883ba7c9cbe493b085c29926bd41b66afc31ff72cf17ff4fb60dcd5"
 dependencies = [
  "ansi_term",
  "chrono",
@@ -1844,9 +1835,9 @@ checksum = "bb0d2e7be6ae3a5fa87eed5fb451aff96f2573d2694942e40543ae0bbe19c796"
 
 [[package]]
 name = "unicode-xid"
-version = "0.2.1"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f7fe0bb3479651439c9112f72b6c505038574c9fbb575ed1bf3b797fa39dd564"
+checksum = "8ccb82d61f80a663efe1f787a51b16b5a51e3314d6ac365b08639f52387b33f3"
 
 [[package]]
 name = "url"
@@ -1959,18 +1950,18 @@ dependencies = [
 
 [[package]]
 name = "xshell"
-version = "0.1.9"
+version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6f18102278453c8f70ea5c514ac78cb4c73a0ef72a8273d17094b52f9584c0c1"
+checksum = "aa25217c682f9f991d7889238a99e65eb8431c266d36e0f4e850a73773415473"
 dependencies = [
  "xshell-macros",
 ]
 
 [[package]]
 name = "xshell-macros"
-version = "0.1.9"
+version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6093c460064572007f885facc70bb0ca5e40a83ea7ff8b16c1abbee56fd2e767"
+checksum = "4404d53d2113af4fa31c58326eb7b37d6d7bf11ba87520787cddeaff45385c72"
 
 [[package]]
 name = "xtask"
diff --git a/crates/hir/src/display.rs b/crates/hir/src/display.rs
index 01a4d205f..508ac37c2 100644
--- a/crates/hir/src/display.rs
+++ b/crates/hir/src/display.rs
@@ -170,7 +170,7 @@ impl HirDisplay for Field {
     fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
         write_visibility(self.parent.module(f.db).id, self.visibility(f.db), f)?;
         write!(f, "{}: ", self.name(f.db))?;
-        self.signature_ty(f.db).hir_fmt(f)
+        self.ty(f.db).hir_fmt(f)
     }
 }
 
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 0acfa582a..6fcc58f61 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -509,7 +509,7 @@ impl Field {
     /// 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.
-    pub fn signature_ty(&self, db: &dyn HirDatabase) -> Type {
+    pub fn ty(&self, db: &dyn HirDatabase) -> Type {
         let var_id = self.parent.into();
         let generic_def_id: GenericDefId = match self.parent {
             VariantDef::Struct(it) => it.id.into(),
@@ -1744,6 +1744,10 @@ impl Type {
         }
     }
 
+    pub fn strip_references(&self) -> Type {
+        self.derived(self.ty.strip_references().clone())
+    }
+
     pub fn is_unknown(&self) -> bool {
         self.ty.is_unknown()
     }
@@ -1984,7 +1988,7 @@ impl Type {
         None
     }
 
-    pub fn type_parameters(&self) -> impl Iterator<Item = Type> + '_ {
+    pub fn type_arguments(&self) -> impl Iterator<Item = Type> + '_ {
         self.ty
             .strip_references()
             .as_adt()
diff --git a/crates/hir_def/src/attr.rs b/crates/hir_def/src/attr.rs
index d9294d93a..0171d8a92 100644
--- a/crates/hir_def/src/attr.rs
+++ b/crates/hir_def/src/attr.rs
@@ -484,10 +484,10 @@ impl AttrsWithOwner {
         let mut buf = String::new();
         let mut mapping = Vec::new();
         for (doc, idx) in docs {
-            // str::lines doesn't yield anything for the empty string
             if !doc.is_empty() {
-                for line in doc.split('\n') {
-                    let line = line.trim_end();
+                let mut base_offset = 0;
+                for raw_line in doc.split('\n') {
+                    let line = raw_line.trim_end();
                     let line_len = line.len();
                     let (offset, line) = match line.char_indices().nth(indent) {
                         Some((offset, _)) => (offset, &line[offset..]),
@@ -498,9 +498,13 @@ impl AttrsWithOwner {
                     mapping.push((
                         TextRange::new(buf_offset.try_into().ok()?, buf.len().try_into().ok()?),
                         idx,
-                        TextRange::new(offset.try_into().ok()?, line_len.try_into().ok()?),
+                        TextRange::at(
+                            (base_offset + offset).try_into().ok()?,
+                            line_len.try_into().ok()?,
+                        ),
                     ));
                     buf.push('\n');
+                    base_offset += raw_line.len() + 1;
                 }
             } else {
                 buf.push('\n');
diff --git a/crates/hir_def/src/find_path.rs b/crates/hir_def/src/find_path.rs
index dc3f2908f..c06a37294 100644
--- a/crates/hir_def/src/find_path.rs
+++ b/crates/hir_def/src/find_path.rs
@@ -130,7 +130,8 @@ fn find_path_inner(
     }
 
     // - if the item is the crate root of a dependency crate, return the name from the extern prelude
-    for (name, def_id) in root.def_map(db).extern_prelude() {
+    let root_def_map = root.def_map(db);
+    for (name, def_id) in root_def_map.extern_prelude() {
         if item == ItemInNs::Types(*def_id) {
             let name = scope_name.unwrap_or_else(|| name.clone());
             return Some(ModPath::from_segments(PathKind::Plain, vec![name]));
@@ -138,7 +139,8 @@ fn find_path_inner(
     }
 
     // - if the item is in the prelude, return the name from there
-    if let Some(prelude_module) = def_map.prelude() {
+    if let Some(prelude_module) = root_def_map.prelude() {
+        // Preludes in block DefMaps are ignored, only the crate DefMap is searched
         let prelude_def_map = prelude_module.def_map(db);
         let prelude_scope: &crate::item_scope::ItemScope =
             &prelude_def_map[prelude_module.local_id].scope;
@@ -1057,4 +1059,28 @@ fn f() {
             "dep",
         );
     }
+
+    #[test]
+    fn prelude_with_inner_items() {
+        check_found_path(
+            r#"
+//- /main.rs crate:main deps:std
+fn f() {
+    fn inner() {}
+    $0
+}
+//- /std.rs crate:std
+pub mod prelude {
+    pub enum Option { None }
+    pub use Option::*;
+}
+#[prelude_import]
+pub use prelude::*;
+        "#,
+            "None",
+            "None",
+            "None",
+            "None",
+        );
+    }
 }
diff --git a/crates/hir_expand/src/db.rs b/crates/hir_expand/src/db.rs
index 1e4b0cc19..3e9abd8a1 100644
--- a/crates/hir_expand/src/db.rs
+++ b/crates/hir_expand/src/db.rs
@@ -3,14 +3,14 @@
 use std::sync::Arc;
 
 use base_db::{salsa, SourceDatabase};
-use mbe::{ExpandError, ExpandResult, MacroDef, MacroRules};
+use mbe::{ExpandError, ExpandResult};
 use parser::FragmentKind;
 use syntax::{
     algo::diff,
-    ast::{MacroStmts, NameOwner},
+    ast::{self, NameOwner},
     AstNode, GreenNode, Parse,
     SyntaxKind::*,
-    SyntaxNode,
+    SyntaxNode, SyntaxToken,
 };
 
 use crate::{
@@ -27,23 +27,28 @@ const TOKEN_LIMIT: usize = 524288;
 
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub enum TokenExpander {
-    MacroRules(mbe::MacroRules),
-    MacroDef(mbe::MacroDef),
+    /// Old-style `macro_rules`.
+    MacroRules { mac: mbe::MacroRules, def_site_token_map: mbe::TokenMap },
+    /// AKA macros 2.0.
+    MacroDef { mac: mbe::MacroDef, def_site_token_map: mbe::TokenMap },
+    /// Stuff like `line!` and `file!`.
     Builtin(BuiltinFnLikeExpander),
+    /// `derive(Copy)` and such.
     BuiltinDerive(BuiltinDeriveExpander),
+    /// The thing we love the most here in rust-analyzer -- procedural macros.
     ProcMacro(ProcMacroExpander),
 }
 
 impl TokenExpander {
-    pub fn expand(
+    fn expand(
         &self,
         db: &dyn AstDatabase,
         id: LazyMacroId,
         tt: &tt::Subtree,
     ) -> mbe::ExpandResult<tt::Subtree> {
         match self {
-            TokenExpander::MacroRules(it) => it.expand(tt),
-            TokenExpander::MacroDef(it) => it.expand(tt),
+            TokenExpander::MacroRules { mac, .. } => mac.expand(tt),
+            TokenExpander::MacroDef { mac, .. } => mac.expand(tt),
             TokenExpander::Builtin(it) => it.expand(db, id, tt),
             // FIXME switch these to ExpandResult as well
             TokenExpander::BuiltinDerive(it) => it.expand(db, id, tt).into(),
@@ -56,23 +61,23 @@ impl TokenExpander {
         }
     }
 
-    pub fn map_id_down(&self, id: tt::TokenId) -> tt::TokenId {
+    pub(crate) fn map_id_down(&self, id: tt::TokenId) -> tt::TokenId {
         match self {
-            TokenExpander::MacroRules(it) => it.map_id_down(id),
-            TokenExpander::MacroDef(it) => it.map_id_down(id),
-            TokenExpander::Builtin(..) => id,
-            TokenExpander::BuiltinDerive(..) => id,
-            TokenExpander::ProcMacro(..) => id,
+            TokenExpander::MacroRules { mac, .. } => mac.map_id_down(id),
+            TokenExpander::MacroDef { mac, .. } => mac.map_id_down(id),
+            TokenExpander::Builtin(..)
+            | TokenExpander::BuiltinDerive(..)
+            | TokenExpander::ProcMacro(..) => id,
         }
     }
 
-    pub fn map_id_up(&self, id: tt::TokenId) -> (tt::TokenId, mbe::Origin) {
+    pub(crate) fn map_id_up(&self, id: tt::TokenId) -> (tt::TokenId, mbe::Origin) {
         match self {
-            TokenExpander::MacroRules(it) => it.map_id_up(id),
-            TokenExpander::MacroDef(it) => it.map_id_up(id),
-            TokenExpander::Builtin(..) => (id, mbe::Origin::Call),
-            TokenExpander::BuiltinDerive(..) => (id, mbe::Origin::Call),
-            TokenExpander::ProcMacro(..) => (id, mbe::Origin::Call),
+            TokenExpander::MacroRules { mac, .. } => mac.map_id_up(id),
+            TokenExpander::MacroDef { mac, .. } => mac.map_id_up(id),
+            TokenExpander::Builtin(..)
+            | TokenExpander::BuiltinDerive(..)
+            | TokenExpander::ProcMacro(..) => (id, mbe::Origin::Call),
         }
     }
 }
@@ -82,28 +87,48 @@ impl TokenExpander {
 pub trait AstDatabase: SourceDatabase {
     fn ast_id_map(&self, file_id: HirFileId) -> Arc<AstIdMap>;
 
+    /// Main public API -- parsis a hir file, not caring whether it's a real
+    /// file or a macro expansion.
     #[salsa::transparent]
     fn parse_or_expand(&self, file_id: HirFileId) -> Option<SyntaxNode>;
-
-    #[salsa::interned]
-    fn intern_macro(&self, macro_call: MacroCallLoc) -> LazyMacroId;
-    fn macro_arg_text(&self, id: MacroCallId) -> Option<GreenNode>;
-    #[salsa::transparent]
-    fn macro_arg(&self, id: MacroCallId) -> Option<Arc<(tt::Subtree, mbe::TokenMap)>>;
-    fn macro_def(&self, id: MacroDefId) -> Option<Arc<(TokenExpander, mbe::TokenMap)>>;
+    /// Implementation for the macro case.
     fn parse_macro_expansion(
         &self,
         macro_file: MacroFile,
     ) -> ExpandResult<Option<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)>>;
-    fn macro_expand(&self, macro_call: MacroCallId) -> ExpandResult<Option<Arc<tt::Subtree>>>;
-
-    /// Firewall query that returns the error from the `macro_expand` query.
-    fn macro_expand_error(&self, macro_call: MacroCallId) -> Option<ExpandError>;
 
+    /// Macro ids. That's probably the tricksiest bit in rust-analyzer, and the
+    /// reason why we use salsa at all.
+    ///
+    /// We encode macro definitions into ids of macro calls, this what allows us
+    /// to be incremental.
+    #[salsa::interned]
+    fn intern_macro(&self, macro_call: MacroCallLoc) -> LazyMacroId;
+    /// Certain built-in macros are eager (`format!(concat!("file: ", file!(), "{}"")), 92`).
+    /// For them, we actually want to encode the whole token tree as an argument.
     #[salsa::interned]
     fn intern_eager_expansion(&self, eager: EagerCallLoc) -> EagerMacroId;
 
+    /// Lowers syntactic macro call to a token tree representation.
+    #[salsa::transparent]
+    fn macro_arg(&self, id: MacroCallId) -> Option<Arc<(tt::Subtree, mbe::TokenMap)>>;
+    /// Extracts syntax node, corresponding to a macro call. That's a firewall
+    /// query, only typing in the macro call itself changes the returned
+    /// subtree.
+    fn macro_arg_text(&self, id: MacroCallId) -> Option<GreenNode>;
+    /// Gets the expander for this macro. This compiles declarative macros, and
+    /// just fetches procedural ones.
+    fn macro_def(&self, id: MacroDefId) -> Option<Arc<TokenExpander>>;
+
+    /// Expand macro call to a token tree. This query is LRUed (we keep 128 or so results in memory)
+    fn macro_expand(&self, macro_call: MacroCallId) -> ExpandResult<Option<Arc<tt::Subtree>>>;
+    /// Special case of the previous query for procedural macros. We can't LRU
+    /// proc macros, since they are not deterministic in general, and
+    /// non-determinism breaks salsa in a very, very, very bad way. @edwin0cheng
+    /// heroically debugged this once!
     fn expand_proc_macro(&self, call: MacroCallId) -> Result<tt::Subtree, mbe::ExpandError>;
+    /// Firewall query that returns the error from the `macro_expand` query.
+    fn macro_expand_error(&self, macro_call: MacroCallId) -> Option<ExpandError>;
 
     fn hygiene_frame(&self, file_id: HirFileId) -> Arc<HygieneFrame>;
 }
@@ -115,36 +140,159 @@ pub trait AstDatabase: SourceDatabase {
 pub fn expand_hypothetical(
     db: &dyn AstDatabase,
     actual_macro_call: MacroCallId,
-    hypothetical_args: &syntax::ast::TokenTree,
-    token_to_map: syntax::SyntaxToken,
-) -> Option<(SyntaxNode, syntax::SyntaxToken)> {
-    let macro_file = MacroFile { macro_call_id: actual_macro_call };
+    hypothetical_args: &ast::TokenTree,
+    token_to_map: SyntaxToken,
+) -> Option<(SyntaxNode, SyntaxToken)> {
     let (tt, tmap_1) = mbe::syntax_node_to_token_tree(hypothetical_args.syntax());
     let range =
         token_to_map.text_range().checked_sub(hypothetical_args.syntax().text_range().start())?;
     let token_id = tmap_1.token_by_range(range)?;
-    let macro_def = expander(db, actual_macro_call)?;
+
+    let lazy_id = match actual_macro_call {
+        MacroCallId::LazyMacro(id) => id,
+        MacroCallId::EagerMacro(_) => return None,
+    };
+
+    let macro_def = {
+        let loc = db.lookup_intern_macro(lazy_id);
+        db.macro_def(loc.def)?
+    };
+
+    let hypothetical_expansion = macro_def.expand(db, lazy_id, &tt);
+
+    let fragment_kind = to_fragment_kind(db, actual_macro_call);
+
     let (node, tmap_2) =
-        parse_macro_with_arg(db, macro_file, Some(std::sync::Arc::new((tt, tmap_1)))).value?;
-    let token_id = macro_def.0.map_id_down(token_id);
+        mbe::token_tree_to_syntax_node(&hypothetical_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 token = node.syntax_node().covering_element(range).into_token()?;
     Some((node.syntax_node(), token))
 }
 
 fn ast_id_map(db: &dyn AstDatabase, file_id: HirFileId) -> Arc<AstIdMap> {
-    let map =
-        db.parse_or_expand(file_id).map_or_else(AstIdMap::default, |it| AstIdMap::from_source(&it));
+    let map = db.parse_or_expand(file_id).map(|it| AstIdMap::from_source(&it)).unwrap_or_default();
     Arc::new(map)
 }
 
-fn macro_def(db: &dyn AstDatabase, id: MacroDefId) -> Option<Arc<(TokenExpander, mbe::TokenMap)>> {
+fn parse_or_expand(db: &dyn AstDatabase, file_id: HirFileId) -> Option<SyntaxNode> {
+    match file_id.0 {
+        HirFileIdRepr::FileId(file_id) => Some(db.parse(file_id).tree().syntax().clone()),
+        HirFileIdRepr::MacroFile(macro_file) => {
+            db.parse_macro_expansion(macro_file).value.map(|(it, _)| it.syntax_node())
+        }
+    }
+}
+
+fn parse_macro_expansion(
+    db: &dyn AstDatabase,
+    macro_file: MacroFile,
+) -> ExpandResult<Option<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)>> {
+    let _p = profile::span("parse_macro_expansion");
+    let result = db.macro_expand(macro_file.macro_call_id);
+
+    if let Some(err) = &result.err {
+        // Note:
+        // The final goal we would like to make all parse_macro success,
+        // such that the following log will not call anyway.
+        match macro_file.macro_call_id {
+            MacroCallId::LazyMacro(id) => {
+                let loc: MacroCallLoc = db.lookup_intern_macro(id);
+                let node = loc.kind.node(db);
+
+                // collect parent information for warning log
+                let parents = std::iter::successors(loc.kind.file_id().call_node(db), |it| {
+                    it.file_id.call_node(db)
+                })
+                .map(|n| format!("{:#}", n.value))
+                .collect::<Vec<_>>()
+                .join("\n");
+
+                log::warn!(
+                    "fail on macro_parse: (reason: {:?} macro_call: {:#}) parents: {}",
+                    err,
+                    node.value,
+                    parents
+                );
+            }
+            _ => {
+                log::warn!("fail on macro_parse: (reason: {:?})", err);
+            }
+        }
+    }
+    let tt = match result.value {
+        Some(tt) => tt,
+        None => return ExpandResult { value: None, err: result.err },
+    };
+
+    let fragment_kind = to_fragment_kind(db, macro_file.macro_call_id);
+
+    log::debug!("expanded = {}", tt.as_debug_string());
+    log::debug!("kind = {:?}", fragment_kind);
+
+    let (parse, rev_token_map) = match mbe::token_tree_to_syntax_node(&tt, fragment_kind) {
+        Ok(it) => it,
+        Err(err) => {
+            log::debug!(
+                "failed to parse expanstion to {:?} = {}",
+                fragment_kind,
+                tt.as_debug_string()
+            );
+            return ExpandResult::only_err(err);
+        }
+    };
+
+    match result.err {
+        Some(err) => {
+            // Safety check for recursive identity macro.
+            let node = parse.syntax_node();
+            let file: HirFileId = macro_file.into();
+            let call_node = match file.call_node(db) {
+                Some(it) => it,
+                None => {
+                    return ExpandResult::only_err(err);
+                }
+            };
+            if is_self_replicating(&node, &call_node.value) {
+                return ExpandResult::only_err(err);
+            } else {
+                ExpandResult { value: Some((parse, Arc::new(rev_token_map))), err: Some(err) }
+            }
+        }
+        None => {
+            log::debug!("parse = {:?}", parse.syntax_node().kind());
+            ExpandResult { value: Some((parse, Arc::new(rev_token_map))), err: None }
+        }
+    }
+}
+
+fn macro_arg(db: &dyn AstDatabase, id: MacroCallId) -> Option<Arc<(tt::Subtree, mbe::TokenMap)>> {
+    let arg = db.macro_arg_text(id)?;
+    let (tt, tmap) = mbe::syntax_node_to_token_tree(&SyntaxNode::new_root(arg));
+    Some(Arc::new((tt, tmap)))
+}
+
+fn macro_arg_text(db: &dyn AstDatabase, id: MacroCallId) -> Option<GreenNode> {
+    let id = match id {
+        MacroCallId::LazyMacro(id) => id,
+        MacroCallId::EagerMacro(_id) => {
+            // FIXME: support macro_arg for eager macro
+            return None;
+        }
+    };
+    let loc = db.lookup_intern_macro(id);
+    let arg = loc.kind.arg(db)?;
+    Some(arg.green())
+}
+
+fn macro_def(db: &dyn AstDatabase, id: MacroDefId) -> Option<Arc<TokenExpander>> {
     match id.kind {
         MacroDefKind::Declarative(ast_id) => match ast_id.to_node(db) {
-            syntax::ast::Macro::MacroRules(macro_rules) => {
+            ast::Macro::MacroRules(macro_rules) => {
                 let arg = macro_rules.token_tree()?;
-                let (tt, tmap) = mbe::ast_to_token_tree(&arg);
-                let rules = match MacroRules::parse(&tt) {
+                let (tt, def_site_token_map) = mbe::ast_to_token_tree(&arg);
+                let mac = match mbe::MacroRules::parse(&tt) {
                     Ok(it) => it,
                     Err(err) => {
                         let name = macro_rules.name().map(|n| n.to_string()).unwrap_or_default();
@@ -152,12 +300,12 @@ fn macro_def(db: &dyn AstDatabase, id: MacroDefId) -> Option<Arc<(TokenExpander,
                         return None;
                     }
                 };
-                Some(Arc::new((TokenExpander::MacroRules(rules), tmap)))
+                Some(Arc::new(TokenExpander::MacroRules { mac, def_site_token_map }))
             }
-            syntax::ast::Macro::MacroDef(macro_def) => {
+            ast::Macro::MacroDef(macro_def) => {
                 let arg = macro_def.body()?;
-                let (tt, tmap) = mbe::ast_to_token_tree(&arg);
-                let rules = match MacroDef::parse(&tt) {
+                let (tt, def_site_token_map) = mbe::ast_to_token_tree(&arg);
+                let mac = match mbe::MacroDef::parse(&tt) {
                     Ok(it) => it,
                     Err(err) => {
                         let name = macro_def.name().map(|n| n.to_string()).unwrap_or_default();
@@ -165,41 +313,18 @@ fn macro_def(db: &dyn AstDatabase, id: MacroDefId) -> Option<Arc<(TokenExpander,
                         return None;
                     }
                 };
-                Some(Arc::new((TokenExpander::MacroDef(rules), tmap)))
+                Some(Arc::new(TokenExpander::MacroDef { mac, def_site_token_map }))
             }
         },
-        MacroDefKind::BuiltIn(expander, _) => {
-            Some(Arc::new((TokenExpander::Builtin(expander), mbe::TokenMap::default())))
-        }
+        MacroDefKind::BuiltIn(expander, _) => Some(Arc::new(TokenExpander::Builtin(expander))),
         MacroDefKind::BuiltInDerive(expander, _) => {
-            Some(Arc::new((TokenExpander::BuiltinDerive(expander), mbe::TokenMap::default())))
+            Some(Arc::new(TokenExpander::BuiltinDerive(expander)))
         }
         MacroDefKind::BuiltInEager(..) => None,
-        MacroDefKind::ProcMacro(expander, ..) => {
-            Some(Arc::new((TokenExpander::ProcMacro(expander), mbe::TokenMap::default())))
-        }
+        MacroDefKind::ProcMacro(expander, ..) => Some(Arc::new(TokenExpander::ProcMacro(expander))),
     }
 }
 
-fn macro_arg_text(db: &dyn AstDatabase, id: MacroCallId) -> Option<GreenNode> {
-    let id = match id {
-        MacroCallId::LazyMacro(id) => id,
-        MacroCallId::EagerMacro(_id) => {
-            // FIXME: support macro_arg for eager macro
-            return None;
-        }
-    };
-    let loc = db.lookup_intern_macro(id);
-    let arg = loc.kind.arg(db)?;
-    Some(arg.green())
-}
-
-fn macro_arg(db: &dyn AstDatabase, id: MacroCallId) -> Option<Arc<(tt::Subtree, mbe::TokenMap)>> {
-    let arg = db.macro_arg_text(id)?;
-    let (tt, tmap) = mbe::syntax_node_to_token_tree(&SyntaxNode::new_root(arg));
-    Some(Arc::new((tt, tmap)))
-}
-
 fn macro_expand(db: &dyn AstDatabase, id: MacroCallId) -> ExpandResult<Option<Arc<tt::Subtree>>> {
     macro_expand_with_arg(db, id, None)
 }
@@ -208,19 +333,6 @@ fn macro_expand_error(db: &dyn AstDatabase, macro_call: MacroCallId) -> Option<E
     db.macro_expand(macro_call).err
 }
 
-fn expander(db: &dyn AstDatabase, id: MacroCallId) -> Option<Arc<(TokenExpander, mbe::TokenMap)>> {
-    let lazy_id = match id {
-        MacroCallId::LazyMacro(id) => id,
-        MacroCallId::EagerMacro(_id) => {
-            return None;
-        }
-    };
-
-    let loc = db.lookup_intern_macro(lazy_id);
-    let macro_rules = db.macro_def(loc.def)?;
-    Some(macro_rules)
-}
-
 fn macro_expand_with_arg(
     db: &dyn AstDatabase,
     id: MacroCallId,
@@ -254,7 +366,7 @@ fn macro_expand_with_arg(
         Some(it) => it,
         None => return ExpandResult::str_err("Fail to find macro definition".into()),
     };
-    let ExpandResult { value: tt, err } = macro_rules.0.expand(db, lazy_id, &macro_arg.0);
+    let ExpandResult { value: tt, err } = macro_rules.expand(db, lazy_id, &macro_arg.0);
     // Set a hard limit for the expanded tt
     let count = tt.count();
     if count > TOKEN_LIMIT {
@@ -294,116 +406,11 @@ fn expand_proc_macro(
     expander.expand(db, loc.krate, &macro_arg.0)
 }
 
-fn parse_or_expand(db: &dyn AstDatabase, file_id: HirFileId) -> Option<SyntaxNode> {
-    match file_id.0 {
-        HirFileIdRepr::FileId(file_id) => Some(db.parse(file_id).tree().syntax().clone()),
-        HirFileIdRepr::MacroFile(macro_file) => {
-            db.parse_macro_expansion(macro_file).value.map(|(it, _)| it.syntax_node())
-        }
-    }
-}
-
-fn parse_macro_expansion(
-    db: &dyn AstDatabase,
-    macro_file: MacroFile,
-) -> ExpandResult<Option<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)>> {
-    parse_macro_with_arg(db, macro_file, None)
-}
-
-fn parse_macro_with_arg(
-    db: &dyn AstDatabase,
-    macro_file: MacroFile,
-    arg: Option<Arc<(tt::Subtree, mbe::TokenMap)>>,
-) -> ExpandResult<Option<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)>> {
-    let macro_call_id = macro_file.macro_call_id;
-    let result = if let Some(arg) = arg {
-        macro_expand_with_arg(db, macro_call_id, Some(arg))
-    } else {
-        db.macro_expand(macro_call_id)
-    };
-
-    let _p = profile::span("parse_macro_expansion");
-
-    if let Some(err) = &result.err {
-        // Note:
-        // The final goal we would like to make all parse_macro success,
-        // such that the following log will not call anyway.
-        match macro_call_id {
-            MacroCallId::LazyMacro(id) => {
-                let loc: MacroCallLoc = db.lookup_intern_macro(id);
-                let node = loc.kind.node(db);
-
-                // collect parent information for warning log
-                let parents = std::iter::successors(loc.kind.file_id().call_node(db), |it| {
-                    it.file_id.call_node(db)
-                })
-                .map(|n| format!("{:#}", n.value))
-                .collect::<Vec<_>>()
-                .join("\n");
-
-                log::warn!(
-                    "fail on macro_parse: (reason: {:?} macro_call: {:#}) parents: {}",
-                    err,
-                    node.value,
-                    parents
-                );
-            }
-            _ => {
-                log::warn!("fail on macro_parse: (reason: {:?})", err);
-            }
-        }
-    }
-    let tt = match result.value {
-        Some(tt) => tt,
-        None => return ExpandResult { value: None, err: result.err },
-    };
-
-    let fragment_kind = to_fragment_kind(db, macro_call_id);
-
-    log::debug!("expanded = {}", tt.as_debug_string());
-    log::debug!("kind = {:?}", fragment_kind);
-
-    let (parse, rev_token_map) = match mbe::token_tree_to_syntax_node(&tt, fragment_kind) {
-        Ok(it) => it,
-        Err(err) => {
-            log::debug!(
-                "failed to parse expanstion to {:?} = {}",
-                fragment_kind,
-                tt.as_debug_string()
-            );
-            return ExpandResult::only_err(err);
-        }
-    };
-
-    match result.err {
-        Some(err) => {
-            // Safety check for recursive identity macro.
-            let node = parse.syntax_node();
-            let file: HirFileId = macro_file.into();
-            let call_node = match file.call_node(db) {
-                Some(it) => it,
-                None => {
-                    return ExpandResult::only_err(err);
-                }
-            };
-            if is_self_replicating(&node, &call_node.value) {
-                return ExpandResult::only_err(err);
-            } else {
-                ExpandResult { value: Some((parse, Arc::new(rev_token_map))), err: Some(err) }
-            }
-        }
-        None => {
-            log::debug!("parse = {:?}", parse.syntax_node().kind());
-            ExpandResult { value: Some((parse, Arc::new(rev_token_map))), err: None }
-        }
-    }
-}
-
 fn is_self_replicating(from: &SyntaxNode, to: &SyntaxNode) -> bool {
     if diff(from, to).is_empty() {
         return true;
     }
-    if let Some(stmts) = MacroStmts::cast(from.clone()) {
+    if let Some(stmts) = ast::MacroStmts::cast(from.clone()) {
         if stmts.statements().any(|stmt| diff(stmt.syntax(), to).is_empty()) {
             return true;
         }
diff --git a/crates/hir_expand/src/hygiene.rs b/crates/hir_expand/src/hygiene.rs
index 779725629..ed61ebca3 100644
--- a/crates/hir_expand/src/hygiene.rs
+++ b/crates/hir_expand/src/hygiene.rs
@@ -5,6 +5,7 @@
 use std::sync::Arc;
 
 use base_db::CrateId;
+use db::TokenExpander;
 use either::Either;
 use mbe::Origin;
 use parser::SyntaxKind;
@@ -115,7 +116,7 @@ struct HygieneInfo {
     /// The `macro_rules!` arguments.
     def_start: Option<InFile<TextSize>>,
 
-    macro_def: Arc<(db::TokenExpander, mbe::TokenMap)>,
+    macro_def: Arc<TokenExpander>,
     macro_arg: Arc<(tt::Subtree, mbe::TokenMap)>,
     exp_map: Arc<mbe::TokenMap>,
 }
@@ -124,13 +125,16 @@ impl HygieneInfo {
     fn map_ident_up(&self, token: TextRange) -> Option<(InFile<TextRange>, Origin)> {
         let token_id = self.exp_map.token_by_range(token)?;
 
-        let (token_id, origin) = self.macro_def.0.map_id_up(token_id);
+        let (token_id, origin) = self.macro_def.map_id_up(token_id);
         let (token_map, tt) = match origin {
             mbe::Origin::Call => (&self.macro_arg.1, self.arg_start),
-            mbe::Origin::Def => (
-                &self.macro_def.1,
-                *self.def_start.as_ref().expect("`Origin::Def` used with non-`macro_rules!` macro"),
-            ),
+            mbe::Origin::Def => match (&*self.macro_def, self.def_start) {
+                (TokenExpander::MacroDef { def_site_token_map, .. }, Some(tt))
+                | (TokenExpander::MacroRules { def_site_token_map, .. }, Some(tt)) => {
+                    (def_site_token_map, tt)
+                }
+                _ => panic!("`Origin::Def` used with non-`macro_rules!` macro"),
+            },
         };
 
         let range = token_map.range_by_token(token_id)?.by_kind(SyntaxKind::IDENT)?;
diff --git a/crates/hir_expand/src/lib.rs b/crates/hir_expand/src/lib.rs
index a0e6aec62..0402640de 100644
--- a/crates/hir_expand/src/lib.rs
+++ b/crates/hir_expand/src/lib.rs
@@ -351,7 +351,7 @@ pub struct ExpansionInfo {
     /// The `macro_rules!` arguments.
     def: Option<InFile<ast::TokenTree>>,
 
-    macro_def: Arc<(db::TokenExpander, mbe::TokenMap)>,
+    macro_def: Arc<db::TokenExpander>,
     macro_arg: Arc<(tt::Subtree, mbe::TokenMap)>,
     exp_map: Arc<mbe::TokenMap>,
 }
@@ -368,7 +368,7 @@ impl ExpansionInfo {
         assert_eq!(token.file_id, self.arg.file_id);
         let range = token.value.text_range().checked_sub(self.arg.value.text_range().start())?;
         let token_id = self.macro_arg.1.token_by_range(range)?;
-        let token_id = self.macro_def.0.map_id_down(token_id);
+        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())?;
 
@@ -383,17 +383,16 @@ impl ExpansionInfo {
     ) -> Option<(InFile<SyntaxToken>, Origin)> {
         let token_id = self.exp_map.token_by_range(token.value.text_range())?;
 
-        let (token_id, origin) = self.macro_def.0.map_id_up(token_id);
+        let (token_id, origin) = self.macro_def.map_id_up(token_id);
         let (token_map, tt) = match origin {
             mbe::Origin::Call => (&self.macro_arg.1, self.arg.clone()),
-            mbe::Origin::Def => (
-                &self.macro_def.1,
-                self.def
-                    .as_ref()
-                    .expect("`Origin::Def` used with non-`macro_rules!` macro")
-                    .as_ref()
-                    .map(|tt| tt.syntax().clone()),
-            ),
+            mbe::Origin::Def => match (&*self.macro_def, self.def.as_ref()) {
+                (db::TokenExpander::MacroRules { def_site_token_map, .. }, Some(tt))
+                | (db::TokenExpander::MacroDef { def_site_token_map, .. }, Some(tt)) => {
+                    (def_site_token_map, tt.as_ref().map(|tt| tt.syntax().clone()))
+                }
+                _ => panic!("`Origin::Def` used with non-`macro_rules!` macro"),
+            },
         };
 
         let range = token_map.range_by_token(token_id)?.by_kind(token.value.kind())?;
diff --git a/crates/hir_ty/src/db.rs b/crates/hir_ty/src/db.rs
index cf67d4266..9da0a02e3 100644
--- a/crates/hir_ty/src/db.rs
+++ b/crates/hir_ty/src/db.rs
@@ -70,6 +70,7 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     fn trait_environment(&self, def: GenericDefId) -> Arc<crate::TraitEnvironment>;
 
     #[salsa::invoke(crate::lower::generic_defaults_query)]
+    #[salsa::cycle(crate::lower::generic_defaults_recover)]
     fn generic_defaults(&self, def: GenericDefId) -> Arc<[Binders<Ty>]>;
 
     #[salsa::invoke(InherentImpls::inherent_impls_in_crate_query)]
diff --git a/crates/hir_ty/src/lower.rs b/crates/hir_ty/src/lower.rs
index 7fd46becd..c99dd8d0a 100644
--- a/crates/hir_ty/src/lower.rs
+++ b/crates/hir_ty/src/lower.rs
@@ -414,17 +414,16 @@ impl<'a> TyLoweringContext<'a> {
                     self.lower_trait_ref_from_resolved_path(trait_, resolved_segment, self_ty);
                 let ty = if remaining_segments.len() == 1 {
                     let segment = remaining_segments.first().unwrap();
-                    let found = associated_type_by_name_including_super_traits(
-                        self.db,
-                        trait_ref,
-                        &segment.name,
-                    );
+                    let found = self
+                        .db
+                        .trait_data(trait_ref.hir_trait_id())
+                        .associated_type_by_name(&segment.name);
                     match found {
-                        Some((super_trait_ref, associated_ty)) => {
+                        Some(associated_ty) => {
                             // FIXME handle type parameters on the segment
                             TyKind::Alias(AliasTy::Projection(ProjectionTy {
                                 associated_ty_id: to_assoc_type_id(associated_ty),
-                                substitution: super_trait_ref.substitution,
+                                substitution: trait_ref.substitution,
                             }))
                             .intern(&Interner)
                         }
@@ -1089,6 +1088,27 @@ pub(crate) fn generic_defaults_query(
     defaults
 }
 
+pub(crate) fn generic_defaults_recover(
+    db: &dyn HirDatabase,
+    _cycle: &[String],
+    def: &GenericDefId,
+) -> Arc<[Binders<Ty>]> {
+    let generic_params = generics(db.upcast(), *def);
+
+    // we still need one default per parameter
+    let defaults = generic_params
+        .iter()
+        .enumerate()
+        .map(|(idx, _)| {
+            let ty = TyKind::Error.intern(&Interner);
+
+            crate::make_only_type_binders(idx, ty)
+        })
+        .collect();
+
+    defaults
+}
+
 fn fn_sig_for_fn(db: &dyn HirDatabase, def: FunctionId) -> PolyFnSig {
     let data = db.function_data(def);
     let resolver = def.resolver(db.upcast());
diff --git a/crates/hir_ty/src/tests/regression.rs b/crates/hir_ty/src/tests/regression.rs
index 9cd9f473d..d14f5c9bb 100644
--- a/crates/hir_ty/src/tests/regression.rs
+++ b/crates/hir_ty/src/tests/regression.rs
@@ -1012,3 +1012,41 @@ fn lifetime_from_chalk_during_deref() {
         "#,
     )
 }
+
+#[test]
+fn issue_8686() {
+    check_infer(
+        r#"
+pub trait Try: FromResidual {
+    type Output;
+    type Residual;
+}
+pub trait FromResidual<R = <Self as Try>::Residual> {
+     fn from_residual(residual: R) -> Self;
+}
+
+struct ControlFlow<B, C>;
+impl<B, C> Try for ControlFlow<B, C> {
+    type Output = C;
+    type Residual = ControlFlow<B, !>;
+}
+impl<B, C> FromResidual for ControlFlow<B, C> {
+    fn from_residual(r: ControlFlow<B, !>) -> Self { ControlFlow }
+}
+
+fn test() {
+    ControlFlow::from_residual(ControlFlow::<u32, !>);
+}
+        "#,
+        expect![[r#"
+            144..152 'residual': R
+            365..366 'r': ControlFlow<B, !>
+            395..410 '{ ControlFlow }': ControlFlow<B, C>
+            397..408 'ControlFlow': ControlFlow<B, C>
+            424..482 '{     ...!>); }': ()
+            430..456 'Contro...sidual': fn from_residual<ControlFlow<u32, {unknown}>, ControlFlow<u32, !>>(ControlFlow<u32, !>) -> ControlFlow<u32, {unknown}>
+            430..479 'Contro...2, !>)': ControlFlow<u32, {unknown}>
+            457..478 'Contro...32, !>': ControlFlow<u32, !>
+        "#]],
+    );
+}
diff --git a/crates/hir_ty/src/utils.rs b/crates/hir_ty/src/utils.rs
index 2f04ee57a..2f490fb92 100644
--- a/crates/hir_ty/src/utils.rs
+++ b/crates/hir_ty/src/utils.rs
@@ -1,6 +1,8 @@
 //! Helper functions for working with def, which don't need to be a separate
 //! query, but can't be computed directly from `*Data` (ie, which need a `db`).
 
+use std::iter;
+
 use chalk_ir::{fold::Shift, BoundVar, DebruijnIndex};
 use hir_def::{
     db::DefDatabase,
@@ -14,8 +16,12 @@ use hir_def::{
     AssocContainerId, GenericDefId, Lookup, TraitId, TypeAliasId, TypeParamId,
 };
 use hir_expand::name::{name, Name};
+use rustc_hash::FxHashSet;
 
-use crate::{db::HirDatabase, Interner, Substitution, TraitRef, TraitRefExt, TyKind, WhereClause};
+use crate::{
+    db::HirDatabase, ChalkTraitId, Interner, Substitution, TraitRef, TraitRefExt, TyKind,
+    WhereClause,
+};
 
 fn direct_super_traits(db: &dyn DefDatabase, trait_: TraitId) -> Vec<TraitId> {
     let resolver = trait_.resolver(db);
@@ -102,25 +108,35 @@ pub fn all_super_traits(db: &dyn DefDatabase, trait_: TraitId) -> Vec<TraitId> {
 /// `all_super_traits` is that we keep track of type parameters; for example if
 /// we have `Self: Trait<u32, i32>` and `Trait<T, U>: OtherTrait<U>` we'll get
 /// `Self: OtherTrait<i32>`.
-pub(super) fn all_super_trait_refs(db: &dyn HirDatabase, trait_ref: TraitRef) -> Vec<TraitRef> {
-    // FIXME: replace by Chalk's `super_traits`, maybe make this a query
+pub(super) fn all_super_trait_refs(db: &dyn HirDatabase, trait_ref: TraitRef) -> SuperTraits {
+    SuperTraits { db, seen: iter::once(trait_ref.trait_id).collect(), stack: vec![trait_ref] }
+}
 
-    // we need to take care a bit here to avoid infinite loops in case of cycles
-    // (i.e. if we have `trait A: B; trait B: A;`)
-    let mut result = vec![trait_ref];
-    let mut i = 0;
-    while i < result.len() {
-        let t = &result[i];
-        // yeah this is quadratic, but trait hierarchies should be flat
-        // enough that this doesn't matter
-        for tt in direct_super_trait_refs(db, t) {
-            if !result.iter().any(|tr| tr.trait_id == tt.trait_id) {
-                result.push(tt);
-            }
+pub(super) struct SuperTraits<'a> {
+    db: &'a dyn HirDatabase,
+    stack: Vec<TraitRef>,
+    seen: FxHashSet<ChalkTraitId>,
+}
+
+impl<'a> SuperTraits<'a> {
+    fn elaborate(&mut self, trait_ref: &TraitRef) {
+        let mut trait_refs = direct_super_trait_refs(self.db, trait_ref);
+        trait_refs.retain(|tr| !self.seen.contains(&tr.trait_id));
+        self.stack.extend(trait_refs);
+    }
+}
+
+impl<'a> Iterator for SuperTraits<'a> {
+    type Item = TraitRef;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if let Some(next) = self.stack.pop() {
+            self.elaborate(&next);
+            Some(next)
+        } else {
+            None
         }
-        i += 1;
     }
-    result
 }
 
 pub(super) fn associated_type_by_name_including_super_traits(
@@ -128,7 +144,7 @@ pub(super) fn associated_type_by_name_including_super_traits(
     trait_ref: TraitRef,
     name: &Name,
 ) -> Option<(TraitRef, TypeAliasId)> {
-    all_super_trait_refs(db, trait_ref).into_iter().find_map(|t| {
+    all_super_trait_refs(db, trait_ref).find_map(|t| {
         let assoc_type = db.trait_data(t.hir_trait_id()).associated_type_by_name(name)?;
         Some((t, assoc_type))
     })
diff --git a/crates/ide/src/diagnostics.rs b/crates/ide/src/diagnostics.rs
index 1c911a8b2..b14f908b7 100644
--- a/crates/ide/src/diagnostics.rs
+++ b/crates/ide/src/diagnostics.rs
@@ -15,6 +15,7 @@ use hir::{
     diagnostics::{Diagnostic as _, DiagnosticCode, DiagnosticSinkBuilder},
     InFile, Semantics,
 };
+use ide_assists::AssistResolveStrategy;
 use ide_db::{base_db::SourceDatabase, RootDatabase};
 use itertools::Itertools;
 use rustc_hash::FxHashSet;
@@ -84,7 +85,7 @@ pub struct DiagnosticsConfig {
 pub(crate) fn diagnostics(
     db: &RootDatabase,
     config: &DiagnosticsConfig,
-    resolve: bool,
+    resolve: &AssistResolveStrategy,
     file_id: FileId,
 ) -> Vec<Diagnostic> {
     let _p = profile::span("diagnostics");
@@ -212,7 +213,7 @@ pub(crate) fn diagnostics(
 fn diagnostic_with_fix<D: DiagnosticWithFix>(
     d: &D,
     sema: &Semantics<RootDatabase>,
-    resolve: bool,
+    resolve: &AssistResolveStrategy,
 ) -> Diagnostic {
     Diagnostic::error(sema.diagnostics_display_range(d.display_source()).range, d.message())
         .with_fix(d.fix(&sema, resolve))
@@ -222,7 +223,7 @@ fn diagnostic_with_fix<D: DiagnosticWithFix>(
 fn warning_with_fix<D: DiagnosticWithFix>(
     d: &D,
     sema: &Semantics<RootDatabase>,
-    resolve: bool,
+    resolve: &AssistResolveStrategy,
 ) -> Diagnostic {
     Diagnostic::hint(sema.diagnostics_display_range(d.display_source()).range, d.message())
         .with_fix(d.fix(&sema, resolve))
@@ -299,6 +300,7 @@ fn unresolved_fix(id: &'static str, label: &str, target: TextRange) -> Assist {
 #[cfg(test)]
 mod tests {
     use expect_test::{expect, Expect};
+    use ide_assists::AssistResolveStrategy;
     use stdx::trim_indent;
     use test_utils::assert_eq_text;
 
@@ -314,7 +316,11 @@ mod tests {
 
         let (analysis, file_position) = fixture::position(ra_fixture_before);
         let diagnostic = analysis
-            .diagnostics(&DiagnosticsConfig::default(), true, file_position.file_id)
+            .diagnostics(
+                &DiagnosticsConfig::default(),
+                AssistResolveStrategy::All,
+                file_position.file_id,
+            )
             .unwrap()
             .pop()
             .unwrap();
@@ -343,7 +349,11 @@ mod tests {
     fn check_no_fix(ra_fixture: &str) {
         let (analysis, file_position) = fixture::position(ra_fixture);
         let diagnostic = analysis
-            .diagnostics(&DiagnosticsConfig::default(), true, file_position.file_id)
+            .diagnostics(
+                &DiagnosticsConfig::default(),
+                AssistResolveStrategy::All,
+                file_position.file_id,
+            )
             .unwrap()
             .pop()
             .unwrap();
@@ -357,7 +367,9 @@ mod tests {
         let diagnostics = files
             .into_iter()
             .flat_map(|file_id| {
-                analysis.diagnostics(&DiagnosticsConfig::default(), true, file_id).unwrap()
+                analysis
+                    .diagnostics(&DiagnosticsConfig::default(), AssistResolveStrategy::All, file_id)
+                    .unwrap()
             })
             .collect::<Vec<_>>();
         assert_eq!(diagnostics.len(), 0, "unexpected diagnostics:\n{:#?}", diagnostics);
@@ -365,8 +377,9 @@ mod tests {
 
     fn check_expect(ra_fixture: &str, expect: Expect) {
         let (analysis, file_id) = fixture::file(ra_fixture);
-        let diagnostics =
-            analysis.diagnostics(&DiagnosticsConfig::default(), true, file_id).unwrap();
+        let diagnostics = analysis
+            .diagnostics(&DiagnosticsConfig::default(), AssistResolveStrategy::All, file_id)
+            .unwrap();
         expect.assert_debug_eq(&diagnostics)
     }
 
@@ -911,11 +924,13 @@ struct Foo {
 
         let (analysis, file_id) = fixture::file(r#"mod foo;"#);
 
-        let diagnostics = analysis.diagnostics(&config, true, file_id).unwrap();
+        let diagnostics =
+            analysis.diagnostics(&config, AssistResolveStrategy::All, file_id).unwrap();
         assert!(diagnostics.is_empty());
 
-        let diagnostics =
-            analysis.diagnostics(&DiagnosticsConfig::default(), true, file_id).unwrap();
+        let diagnostics = analysis
+            .diagnostics(&DiagnosticsConfig::default(), AssistResolveStrategy::All, file_id)
+            .unwrap();
         assert!(!diagnostics.is_empty());
     }
 
@@ -1022,7 +1037,11 @@ impl TestStruct {
 
         let (analysis, file_position) = fixture::position(input);
         let diagnostics = analysis
-            .diagnostics(&DiagnosticsConfig::default(), true, file_position.file_id)
+            .diagnostics(
+                &DiagnosticsConfig::default(),
+                AssistResolveStrategy::All,
+                file_position.file_id,
+            )
             .unwrap();
         assert_eq!(diagnostics.len(), 1);
 
diff --git a/crates/ide/src/diagnostics/fixes.rs b/crates/ide/src/diagnostics/fixes.rs
index 7be8b3459..15821500f 100644
--- a/crates/ide/src/diagnostics/fixes.rs
+++ b/crates/ide/src/diagnostics/fixes.rs
@@ -8,6 +8,7 @@ use hir::{
     },
     HasSource, HirDisplay, InFile, Semantics, VariantDef,
 };
+use ide_assists::AssistResolveStrategy;
 use ide_db::{
     base_db::{AnchoredPathBuf, FileId},
     source_change::{FileSystemEdit, SourceChange},
@@ -35,11 +36,19 @@ pub(crate) trait DiagnosticWithFix: Diagnostic {
     ///
     /// If `resolve` is false, the edit will be computed later, on demand, and
     /// can be omitted.
-    fn fix(&self, sema: &Semantics<RootDatabase>, _resolve: bool) -> Option<Assist>;
+    fn fix(
+        &self,
+        sema: &Semantics<RootDatabase>,
+        _resolve: &AssistResolveStrategy,
+    ) -> Option<Assist>;
 }
 
 impl DiagnosticWithFix for UnresolvedModule {
-    fn fix(&self, sema: &Semantics<RootDatabase>, _resolve: bool) -> Option<Assist> {
+    fn fix(
+        &self,
+        sema: &Semantics<RootDatabase>,
+        _resolve: &AssistResolveStrategy,
+    ) -> Option<Assist> {
         let root = sema.db.parse_or_expand(self.file)?;
         let unresolved_module = self.decl.to_node(&root);
         Some(fix(
@@ -59,7 +68,11 @@ impl DiagnosticWithFix for UnresolvedModule {
 }
 
 impl DiagnosticWithFix for NoSuchField {
-    fn fix(&self, sema: &Semantics<RootDatabase>, _resolve: bool) -> Option<Assist> {
+    fn fix(
+        &self,
+        sema: &Semantics<RootDatabase>,
+        _resolve: &AssistResolveStrategy,
+    ) -> Option<Assist> {
         let root = sema.db.parse_or_expand(self.file)?;
         missing_record_expr_field_fix(
             &sema,
@@ -70,7 +83,11 @@ impl DiagnosticWithFix for NoSuchField {
 }
 
 impl DiagnosticWithFix for MissingFields {
-    fn fix(&self, sema: &Semantics<RootDatabase>, _resolve: bool) -> Option<Assist> {
+    fn fix(
+        &self,
+        sema: &Semantics<RootDatabase>,
+        _resolve: &AssistResolveStrategy,
+    ) -> Option<Assist> {
         // Note that although we could add a diagnostics to
         // fill the missing tuple field, e.g :
         // `struct A(usize);`
@@ -106,7 +123,11 @@ impl DiagnosticWithFix for MissingFields {
 }
 
 impl DiagnosticWithFix for MissingOkOrSomeInTailExpr {
-    fn fix(&self, sema: &Semantics<RootDatabase>, _resolve: bool) -> Option<Assist> {
+    fn fix(
+        &self,
+        sema: &Semantics<RootDatabase>,
+        _resolve: &AssistResolveStrategy,
+    ) -> Option<Assist> {
         let root = sema.db.parse_or_expand(self.file)?;
         let tail_expr = self.expr.to_node(&root);
         let tail_expr_range = tail_expr.syntax().text_range();
@@ -119,7 +140,11 @@ impl DiagnosticWithFix for MissingOkOrSomeInTailExpr {
 }
 
 impl DiagnosticWithFix for RemoveThisSemicolon {
-    fn fix(&self, sema: &Semantics<RootDatabase>, _resolve: bool) -> Option<Assist> {
+    fn fix(
+        &self,
+        sema: &Semantics<RootDatabase>,
+        _resolve: &AssistResolveStrategy,
+    ) -> Option<Assist> {
         let root = sema.db.parse_or_expand(self.file)?;
 
         let semicolon = self
@@ -139,7 +164,11 @@ impl DiagnosticWithFix for RemoveThisSemicolon {
 }
 
 impl DiagnosticWithFix for IncorrectCase {
-    fn fix(&self, sema: &Semantics<RootDatabase>, resolve: bool) -> Option<Assist> {
+    fn fix(
+        &self,
+        sema: &Semantics<RootDatabase>,
+        resolve: &AssistResolveStrategy,
+    ) -> Option<Assist> {
         let root = sema.db.parse_or_expand(self.file)?;
         let name_node = self.ident.to_node(&root);
 
@@ -149,7 +178,7 @@ impl DiagnosticWithFix for IncorrectCase {
 
         let label = format!("Rename to {}", self.suggested_text);
         let mut res = unresolved_fix("change_case", &label, frange.range);
-        if resolve {
+        if resolve.should_resolve(&res.id) {
             let source_change = rename_with_semantics(sema, file_position, &self.suggested_text);
             res.source_change = Some(source_change.ok().unwrap_or_default());
         }
@@ -159,7 +188,11 @@ impl DiagnosticWithFix for IncorrectCase {
 }
 
 impl DiagnosticWithFix for ReplaceFilterMapNextWithFindMap {
-    fn fix(&self, sema: &Semantics<RootDatabase>, _resolve: bool) -> Option<Assist> {
+    fn fix(
+        &self,
+        sema: &Semantics<RootDatabase>,
+        _resolve: &AssistResolveStrategy,
+    ) -> Option<Assist> {
         let root = sema.db.parse_or_expand(self.file)?;
         let next_expr = self.next_expr.to_node(&root);
         let next_call = ast::MethodCallExpr::cast(next_expr.syntax().clone())?;
diff --git a/crates/ide/src/diagnostics/unlinked_file.rs b/crates/ide/src/diagnostics/unlinked_file.rs
index 7d39f4fbe..93fd25dea 100644
--- a/crates/ide/src/diagnostics/unlinked_file.rs
+++ b/crates/ide/src/diagnostics/unlinked_file.rs
@@ -5,6 +5,7 @@ use hir::{
     diagnostics::{Diagnostic, DiagnosticCode},
     InFile,
 };
+use ide_assists::AssistResolveStrategy;
 use ide_db::{
     base_db::{FileId, FileLoader, SourceDatabase, SourceDatabaseExt},
     source_change::SourceChange,
@@ -50,7 +51,11 @@ impl Diagnostic for UnlinkedFile {
 }
 
 impl DiagnosticWithFix for UnlinkedFile {
-    fn fix(&self, sema: &hir::Semantics<RootDatabase>, _resolve: bool) -> Option<Assist> {
+    fn fix(
+        &self,
+        sema: &hir::Semantics<RootDatabase>,
+        _resolve: &AssistResolveStrategy,
+    ) -> Option<Assist> {
         // If there's an existing module that could add a `mod` item to include the unlinked file,
         // suggest that as a fix.
 
diff --git a/crates/ide/src/inlay_hints.rs b/crates/ide/src/inlay_hints.rs
index d5ef054d8..e0bf660c4 100644
--- a/crates/ide/src/inlay_hints.rs
+++ b/crates/ide/src/inlay_hints.rs
@@ -218,9 +218,7 @@ fn hint_iterator(
     ty: &hir::Type,
 ) -> Option<SmolStr> {
     let db = sema.db;
-    let strukt = std::iter::successors(Some(ty.clone()), |ty| ty.remove_ref())
-        .last()
-        .and_then(|strukt| strukt.as_adt())?;
+    let strukt = ty.strip_references().as_adt()?;
     let krate = strukt.krate(db);
     if krate != famous_defs.core()? {
         return None;
diff --git a/crates/ide/src/lib.rs b/crates/ide/src/lib.rs
index 99e45633e..8e5b72044 100644
--- a/crates/ide/src/lib.rs
+++ b/crates/ide/src/lib.rs
@@ -87,7 +87,9 @@ pub use crate::{
     },
 };
 pub use hir::{Documentation, Semantics};
-pub use ide_assists::{Assist, AssistConfig, AssistId, AssistKind};
+pub use ide_assists::{
+    Assist, AssistConfig, AssistId, AssistKind, AssistResolveStrategy, SingleResolve,
+};
 pub use ide_completion::{
     CompletionConfig, CompletionItem, CompletionItemKind, CompletionRelevance, ImportEdit,
     InsertTextFormat,
@@ -518,12 +520,13 @@ impl Analysis {
     pub fn assists(
         &self,
         config: &AssistConfig,
-        resolve: bool,
+        resolve: AssistResolveStrategy,
         frange: FileRange,
     ) -> Cancelable<Vec<Assist>> {
         self.with_db(|db| {
+            let ssr_assists = ssr::ssr_assists(db, &resolve, frange);
             let mut acc = Assist::get(db, config, resolve, frange);
-            ssr::add_ssr_assist(db, &mut acc, resolve, frange);
+            acc.extend(ssr_assists.into_iter());
             acc
         })
     }
@@ -532,10 +535,10 @@ impl Analysis {
     pub fn diagnostics(
         &self,
         config: &DiagnosticsConfig,
-        resolve: bool,
+        resolve: AssistResolveStrategy,
         file_id: FileId,
     ) -> Cancelable<Vec<Diagnostic>> {
-        self.with_db(|db| diagnostics::diagnostics(db, config, resolve, file_id))
+        self.with_db(|db| diagnostics::diagnostics(db, config, &resolve, file_id))
     }
 
     /// Convenience function to return assists + quick fixes for diagnostics
@@ -543,7 +546,7 @@ impl Analysis {
         &self,
         assist_config: &AssistConfig,
         diagnostics_config: &DiagnosticsConfig,
-        resolve: bool,
+        resolve: AssistResolveStrategy,
         frange: FileRange,
     ) -> Cancelable<Vec<Assist>> {
         let include_fixes = match &assist_config.allowed {
@@ -552,17 +555,21 @@ impl Analysis {
         };
 
         self.with_db(|db| {
+            let ssr_assists = ssr::ssr_assists(db, &resolve, frange);
+            let diagnostic_assists = if include_fixes {
+                diagnostics::diagnostics(db, diagnostics_config, &resolve, frange.file_id)
+                    .into_iter()
+                    .filter_map(|it| it.fix)
+                    .filter(|it| it.target.intersect(frange.range).is_some())
+                    .collect()
+            } else {
+                Vec::new()
+            };
+
             let mut res = Assist::get(db, assist_config, resolve, frange);
-            ssr::add_ssr_assist(db, &mut res, resolve, frange);
-
-            if include_fixes {
-                res.extend(
-                    diagnostics::diagnostics(db, diagnostics_config, resolve, frange.file_id)
-                        .into_iter()
-                        .filter_map(|it| it.fix)
-                        .filter(|it| it.target.intersect(frange.range).is_some()),
-                );
-            }
+            res.extend(ssr_assists.into_iter());
+            res.extend(diagnostic_assists.into_iter());
+
             res
         })
     }
diff --git a/crates/ide/src/prime_caches.rs b/crates/ide/src/prime_caches.rs
index 03597f507..d912a01b8 100644
--- a/crates/ide/src/prime_caches.rs
+++ b/crates/ide/src/prime_caches.rs
@@ -27,6 +27,7 @@ pub(crate) fn prime_caches(db: &RootDatabase, cb: &(dyn Fn(PrimeCachesProgress)
     let topo = &graph.crates_in_topological_order();
 
     cb(PrimeCachesProgress::Started);
+    // Take care to emit the finish signal  even when the computation is canceled.
     let _d = stdx::defer(|| cb(PrimeCachesProgress::Finished));
 
     // FIXME: This would be easy to parallelize, since it's in the ideal ordering for that.
diff --git a/crates/ide/src/runnables.rs b/crates/ide/src/runnables.rs
index 3eb9e27ee..f76715d84 100644
--- a/crates/ide/src/runnables.rs
+++ b/crates/ide/src/runnables.rs
@@ -304,11 +304,11 @@ fn module_def_doctest(sema: &Semantics<RootDatabase>, def: hir::ModuleDef) -> Op
                         let name = adt.name(sema.db);
                         let idx = path.rfind(':').map_or(0, |idx| idx + 1);
                         let (prefix, suffix) = path.split_at(idx);
-                        let mut ty_params = ty.type_parameters().peekable();
-                        let params = if ty_params.peek().is_some() {
+                        let mut ty_args = ty.type_arguments().peekable();
+                        let params = if ty_args.peek().is_some() {
                             format!(
                                 "<{}>",
-                                ty_params.format_with(", ", |ty, cb| cb(&ty.display(sema.db)))
+                                ty_args.format_with(", ", |ty, cb| cb(&ty.display(sema.db)))
                             )
                         } else {
                             String::new()
diff --git a/crates/ide/src/ssr.rs b/crates/ide/src/ssr.rs
index f3638d928..57ec80261 100644
--- a/crates/ide/src/ssr.rs
+++ b/crates/ide/src/ssr.rs
@@ -2,18 +2,23 @@
 //! assist in ide_assists because that would require the ide_assists crate
 //! depend on the ide_ssr crate.
 
-use ide_assists::{Assist, AssistId, AssistKind, GroupLabel};
+use ide_assists::{Assist, AssistId, AssistKind, AssistResolveStrategy, GroupLabel};
 use ide_db::{base_db::FileRange, label::Label, source_change::SourceChange, RootDatabase};
 
-pub(crate) fn add_ssr_assist(
+pub(crate) fn ssr_assists(
     db: &RootDatabase,
-    base: &mut Vec<Assist>,
-    resolve: bool,
+    resolve: &AssistResolveStrategy,
     frange: FileRange,
-) -> Option<()> {
-    let (match_finder, comment_range) = ide_ssr::ssr_from_comment(db, frange)?;
+) -> Vec<Assist> {
+    let mut ssr_assists = Vec::with_capacity(2);
 
-    let (source_change_for_file, source_change_for_workspace) = if resolve {
+    let (match_finder, comment_range) = match ide_ssr::ssr_from_comment(db, frange) {
+        Some(ssr_data) => ssr_data,
+        None => return ssr_assists,
+    };
+    let id = AssistId("ssr", AssistKind::RefactorRewrite);
+
+    let (source_change_for_file, source_change_for_workspace) = if resolve.should_resolve(&id) {
         let edits = match_finder.edits();
 
         let source_change_for_file = {
@@ -35,16 +40,17 @@ pub(crate) fn add_ssr_assist(
 
     for (label, source_change) in assists.into_iter() {
         let assist = Assist {
-            id: AssistId("ssr", AssistKind::RefactorRewrite),
+            id,
             label: Label::new(label),
             group: Some(GroupLabel("Apply SSR".into())),
             target: comment_range,
             source_change,
         };
 
-        base.push(assist);
+        ssr_assists.push(assist);
     }
-    Some(())
+
+    ssr_assists
 }
 
 #[cfg(test)]
@@ -52,7 +58,7 @@ mod tests {
     use std::sync::Arc;
 
     use expect_test::expect;
-    use ide_assists::Assist;
+    use ide_assists::{Assist, AssistResolveStrategy};
     use ide_db::{
         base_db::{fixture::WithFixture, salsa::Durability, FileRange},
         symbol_index::SymbolsDatabase,
@@ -60,24 +66,14 @@ mod tests {
     };
     use rustc_hash::FxHashSet;
 
-    use super::add_ssr_assist;
+    use super::ssr_assists;
 
-    fn get_assists(ra_fixture: &str, resolve: bool) -> Vec<Assist> {
+    fn get_assists(ra_fixture: &str, resolve: AssistResolveStrategy) -> Vec<Assist> {
         let (mut db, file_id, range_or_offset) = RootDatabase::with_range_or_offset(ra_fixture);
         let mut local_roots = FxHashSet::default();
         local_roots.insert(ide_db::base_db::fixture::WORKSPACE);
         db.set_local_roots_with_durability(Arc::new(local_roots), Durability::HIGH);
-
-        let mut assists = vec![];
-
-        add_ssr_assist(
-            &db,
-            &mut assists,
-            resolve,
-            FileRange { file_id, range: range_or_offset.into() },
-        );
-
-        assists
+        ssr_assists(&db, &resolve, FileRange { file_id, range: range_or_offset.into() })
     }
 
     #[test]
@@ -88,16 +84,13 @@ mod tests {
             // This is foo $0
             fn foo() {}
             "#;
-        let resolve = true;
-
-        let assists = get_assists(ra_fixture, resolve);
+        let assists = get_assists(ra_fixture, AssistResolveStrategy::All);
 
         assert_eq!(0, assists.len());
     }
 
     #[test]
     fn resolve_edits_true() {
-        let resolve = true;
         let assists = get_assists(
             r#"
             //- /lib.rs
@@ -109,7 +102,7 @@ mod tests {
             //- /bar.rs
             fn bar() { 2 }
             "#,
-            resolve,
+            AssistResolveStrategy::All,
         );
 
         assert_eq!(2, assists.len());
@@ -200,7 +193,6 @@ mod tests {
 
     #[test]
     fn resolve_edits_false() {
-        let resolve = false;
         let assists = get_assists(
             r#"
             //- /lib.rs
@@ -212,7 +204,7 @@ mod tests {
             //- /bar.rs
             fn bar() { 2 }
             "#,
-            resolve,
+            AssistResolveStrategy::None,
         );
 
         assert_eq!(2, assists.len());
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html b/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html
index 638f42c2f..8d83ba206 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html
@@ -142,6 +142,7 @@ It is beyond me why you'd use these when you got ///
 ```rust
 </span><span class="keyword injected">let</span><span class="none injected"> </span><span class="punctuation injected">_</span><span class="none injected"> </span><span class="operator injected">=</span><span class="none injected"> </span><span class="function injected">example</span><span class="parenthesis injected">(</span><span class="operator injected">&</span><span class="bracket injected">[</span><span class="numeric_literal injected">1</span><span class="comma injected">,</span><span class="none injected"> </span><span class="numeric_literal injected">2</span><span class="comma injected">,</span><span class="none injected"> </span><span class="numeric_literal injected">3</span><span class="bracket injected">]</span><span class="parenthesis injected">)</span><span class="semicolon injected">;</span><span class="comment documentation">
 ```
+</span><span class="function documentation injected intra_doc_link">[`block_comments2`]</span><span class="comment documentation"> tests these with indentation
  */</span>
 <span class="keyword">pub</span> <span class="keyword">fn</span> <span class="function declaration">block_comments</span><span class="parenthesis">(</span><span class="parenthesis">)</span> <span class="brace">{</span><span class="brace">}</span>
 
@@ -150,5 +151,6 @@ It is beyond me why you'd use these when you got ///
     ```rust
 </span><span class="comment documentation"> </span><span class="none injected">   </span><span class="keyword injected">let</span><span class="none injected"> </span><span class="punctuation injected">_</span><span class="none injected"> </span><span class="operator injected">=</span><span class="none injected"> </span><span class="function injected">example</span><span class="parenthesis injected">(</span><span class="operator injected">&</span><span class="bracket injected">[</span><span class="numeric_literal injected">1</span><span class="comma injected">,</span><span class="none injected"> </span><span class="numeric_literal injected">2</span><span class="comma injected">,</span><span class="none injected"> </span><span class="numeric_literal injected">3</span><span class="bracket injected">]</span><span class="parenthesis injected">)</span><span class="semicolon injected">;</span><span class="comment documentation">
     ```
+    </span><span class="function documentation injected intra_doc_link">[`block_comments`]</span><span class="comment documentation"> tests these without indentation
 */</span>
 <span class="keyword">pub</span> <span class="keyword">fn</span> <span class="function declaration">block_comments2</span><span class="parenthesis">(</span><span class="parenthesis">)</span> <span class="brace">{</span><span class="brace">}</span></code></pre>
\ No newline at end of file
diff --git a/crates/ide/src/syntax_highlighting/tests.rs b/crates/ide/src/syntax_highlighting/tests.rs
index 17cc6334b..b6e952b08 100644
--- a/crates/ide/src/syntax_highlighting/tests.rs
+++ b/crates/ide/src/syntax_highlighting/tests.rs
@@ -618,6 +618,7 @@ It is beyond me why you'd use these when you got ///
 ```rust
 let _ = example(&[1, 2, 3]);
 ```
+[`block_comments2`] tests these with indentation
  */
 pub fn block_comments() {}
 
@@ -626,6 +627,7 @@ pub fn block_comments() {}
     ```rust
     let _ = example(&[1, 2, 3]);
     ```
+    [`block_comments`] tests these without indentation
 */
 pub fn block_comments2() {}
 "#
diff --git a/crates/ide_assists/src/assist_context.rs b/crates/ide_assists/src/assist_context.rs
index 8714e4978..112939948 100644
--- a/crates/ide_assists/src/assist_context.rs
+++ b/crates/ide_assists/src/assist_context.rs
@@ -19,7 +19,9 @@ use syntax::{
 };
 use text_edit::{TextEdit, TextEditBuilder};
 
-use crate::{assist_config::AssistConfig, Assist, AssistId, AssistKind, GroupLabel};
+use crate::{
+    assist_config::AssistConfig, Assist, AssistId, AssistKind, AssistResolveStrategy, GroupLabel,
+};
 
 /// `AssistContext` allows to apply an assist or check if it could be applied.
 ///
@@ -105,14 +107,14 @@ impl<'a> AssistContext<'a> {
 }
 
 pub(crate) struct Assists {
-    resolve: bool,
     file: FileId,
+    resolve: AssistResolveStrategy,
     buf: Vec<Assist>,
     allowed: Option<Vec<AssistKind>>,
 }
 
 impl Assists {
-    pub(crate) fn new(ctx: &AssistContext, resolve: bool) -> Assists {
+    pub(crate) fn new(ctx: &AssistContext, resolve: AssistResolveStrategy) -> Assists {
         Assists {
             resolve,
             file: ctx.frange.file_id,
@@ -158,7 +160,7 @@ impl Assists {
     }
 
     fn add_impl(&mut self, mut assist: Assist, f: impl FnOnce(&mut AssistBuilder)) -> Option<()> {
-        let source_change = if self.resolve {
+        let source_change = if self.resolve.should_resolve(&assist.id) {
             let mut builder = AssistBuilder::new(self.file);
             f(&mut builder);
             Some(builder.finish())
@@ -185,7 +187,29 @@ pub(crate) struct AssistBuilder {
     source_change: SourceChange,
 
     /// Maps the original, immutable `SyntaxNode` to a `clone_for_update` twin.
-    mutated_tree: Option<(SyntaxNode, SyntaxNode)>,
+    mutated_tree: Option<TreeMutator>,
+}
+
+pub(crate) struct TreeMutator {
+    immutable: SyntaxNode,
+    mutable_clone: SyntaxNode,
+}
+
+impl TreeMutator {
+    pub(crate) fn new(immutable: &SyntaxNode) -> TreeMutator {
+        let immutable = immutable.ancestors().last().unwrap();
+        let mutable_clone = immutable.clone_for_update();
+        TreeMutator { immutable, mutable_clone }
+    }
+
+    pub(crate) fn make_mut<N: AstNode>(&self, node: &N) -> N {
+        N::cast(self.make_syntax_mut(node.syntax())).unwrap()
+    }
+
+    pub(crate) fn make_syntax_mut(&self, node: &SyntaxNode) -> SyntaxNode {
+        let ptr = SyntaxNodePtr::new(node);
+        ptr.to_node(&self.mutable_clone)
+    }
 }
 
 impl AssistBuilder {
@@ -204,8 +228,8 @@ impl AssistBuilder {
     }
 
     fn commit(&mut self) {
-        if let Some((old, new)) = self.mutated_tree.take() {
-            algo::diff(&old, &new).into_text_edit(&mut self.edit)
+        if let Some(tm) = self.mutated_tree.take() {
+            algo::diff(&tm.immutable, &tm.mutable_clone).into_text_edit(&mut self.edit)
         }
 
         let edit = mem::take(&mut self.edit).finish();
@@ -228,16 +252,7 @@ impl AssistBuilder {
     /// phase, and then get their mutable couterparts using `make_mut` in the
     /// mutable state.
     pub(crate) fn make_mut(&mut self, node: SyntaxNode) -> SyntaxNode {
-        let root = &self
-            .mutated_tree
-            .get_or_insert_with(|| {
-                let immutable = node.ancestors().last().unwrap();
-                let mutable = immutable.clone_for_update();
-                (immutable, mutable)
-            })
-            .1;
-        let ptr = SyntaxNodePtr::new(&&node);
-        ptr.to_node(root)
+        self.mutated_tree.get_or_insert_with(|| TreeMutator::new(&node)).make_syntax_mut(&node)
     }
 
     /// Remove specified `range` of text.
diff --git a/crates/ide_assists/src/handlers/extract_function.rs b/crates/ide_assists/src/handlers/extract_function.rs
index 5f80a40c8..93b28370c 100644
--- a/crates/ide_assists/src/handlers/extract_function.rs
+++ b/crates/ide_assists/src/handlers/extract_function.rs
@@ -16,12 +16,13 @@ use syntax::{
         edit::{AstNodeEdit, IndentLevel},
         AstNode,
     },
+    ted,
     SyntaxKind::{self, BLOCK_EXPR, BREAK_EXPR, COMMENT, PATH_EXPR, RETURN_EXPR},
     SyntaxNode, SyntaxToken, TextRange, TextSize, TokenAtOffset, WalkEvent, T,
 };
 
 use crate::{
-    assist_context::{AssistContext, Assists},
+    assist_context::{AssistContext, Assists, TreeMutator},
     AssistId,
 };
 
@@ -1183,7 +1184,7 @@ fn make_ret_ty(ctx: &AssistContext, module: hir::Module, fun: &Function) -> Opti
         }
         FlowHandler::Try { kind: TryKind::Result { ty: parent_ret_ty } } => {
             let handler_ty = parent_ret_ty
-                .type_parameters()
+                .type_arguments()
                 .nth(1)
                 .map(|ty| make_ty(&ty, ctx, module))
                 .unwrap_or_else(make::ty_unit);
@@ -1366,7 +1367,10 @@ fn rewrite_body_segment(
 
 /// change all usages to account for added `&`/`&mut` for some params
 fn fix_param_usages(ctx: &AssistContext, params: &[Param], syntax: &SyntaxNode) -> SyntaxNode {
-    let mut rewriter = SyntaxRewriter::default();
+    let mut usages_for_param: Vec<(&Param, Vec<ast::Expr>)> = Vec::new();
+
+    let tm = TreeMutator::new(syntax);
+
     for param in params {
         if !param.kind().is_ref() {
             continue;
@@ -1376,30 +1380,39 @@ fn fix_param_usages(ctx: &AssistContext, params: &[Param], syntax: &SyntaxNode)
         let usages = usages
             .iter()
             .filter(|reference| syntax.text_range().contains_range(reference.range))
-            .filter_map(|reference| path_element_of_reference(syntax, reference));
-        for path in usages {
-            match path.syntax().ancestors().skip(1).find_map(ast::Expr::cast) {
+            .filter_map(|reference| path_element_of_reference(syntax, reference))
+            .map(|expr| tm.make_mut(&expr));
+
+        usages_for_param.push((param, usages.collect()));
+    }
+
+    let res = tm.make_syntax_mut(syntax);
+
+    for (param, usages) in usages_for_param {
+        for usage in usages {
+            match usage.syntax().ancestors().skip(1).find_map(ast::Expr::cast) {
                 Some(ast::Expr::MethodCallExpr(_)) | Some(ast::Expr::FieldExpr(_)) => {
                     // do nothing
                 }
                 Some(ast::Expr::RefExpr(node))
                     if param.kind() == ParamKind::MutRef && node.mut_token().is_some() =>
                 {
-                    rewriter.replace_ast(&node.clone().into(), &node.expr().unwrap());
+                    ted::replace(node.syntax(), node.expr().unwrap().syntax());
                 }
                 Some(ast::Expr::RefExpr(node))
                     if param.kind() == ParamKind::SharedRef && node.mut_token().is_none() =>
                 {
-                    rewriter.replace_ast(&node.clone().into(), &node.expr().unwrap());
+                    ted::replace(node.syntax(), node.expr().unwrap().syntax());
                 }
                 Some(_) | None => {
-                    rewriter.replace_ast(&path, &make::expr_prefix(T![*], path.clone()));
+                    let p = &make::expr_prefix(T![*], usage.clone()).clone_for_update();
+                    ted::replace(usage.syntax(), p.syntax())
                 }
-            };
+            }
         }
     }
 
-    rewriter.rewrite(syntax)
+    res
 }
 
 fn update_external_control_flow(handler: &FlowHandler, syntax: &SyntaxNode) -> SyntaxNode {
diff --git a/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs b/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs
index c13c6eebe..ce6998d82 100644
--- a/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs
+++ b/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs
@@ -91,7 +91,7 @@ fn existing_from_impl(
 
     let enum_type = enum_.ty(sema.db);
 
-    let wrapped_type = variant.fields(sema.db).get(0)?.signature_ty(sema.db);
+    let wrapped_type = variant.fields(sema.db).get(0)?.ty(sema.db);
 
     if enum_type.impls_trait(sema.db, from_trait, &[wrapped_type]) {
         Some(())
diff --git a/crates/ide_assists/src/handlers/reorder_impl.rs b/crates/ide_assists/src/handlers/reorder_impl.rs
index 72d889248..54a9a468e 100644
--- a/crates/ide_assists/src/handlers/reorder_impl.rs
+++ b/crates/ide_assists/src/handlers/reorder_impl.rs
@@ -79,9 +79,12 @@ pub(crate) fn reorder_impl(acc: &mut Assists, ctx: &AssistContext) -> Option<()>
         "Sort methods",
         target,
         |builder| {
-            methods.into_iter().zip(sorted).for_each(|(old, new)| {
-                ted::replace(builder.make_ast_mut(old).syntax(), new.clone_for_update().syntax())
-            });
+            let methods =
+                methods.into_iter().map(|fn_| builder.make_ast_mut(fn_)).collect::<Vec<_>>();
+            methods
+                .into_iter()
+                .zip(sorted)
+                .for_each(|(old, new)| ted::replace(old.syntax(), new.clone_for_update().syntax()));
         },
     )
 }
@@ -160,7 +163,7 @@ $0impl Bar for Foo {}
     }
 
     #[test]
-    fn reorder_impl_trait_methods() {
+    fn reorder_impl_trait_functions() {
         check_assist(
             reorder_impl,
             r#"
@@ -197,4 +200,33 @@ impl Bar for Foo {
         "#,
         )
     }
+
+    #[test]
+    fn reorder_impl_trait_methods_uneven_ident_lengths() {
+        check_assist(
+            reorder_impl,
+            r#"
+trait Bar {
+    fn foo(&mut self) {}
+    fn fooo(&mut self) {}
+}
+
+struct Foo;
+impl Bar for Foo {
+    fn fooo(&mut self) {}
+    fn foo(&mut self) {$0}
+}"#,
+            r#"
+trait Bar {
+    fn foo(&mut self) {}
+    fn fooo(&mut self) {}
+}
+
+struct Foo;
+impl Bar for Foo {
+    fn foo(&mut self) {}
+    fn fooo(&mut self) {}
+}"#,
+        )
+    }
 }
diff --git a/crates/ide_assists/src/lib.rs b/crates/ide_assists/src/lib.rs
index 88ae5c9a9..2e0c58504 100644
--- a/crates/ide_assists/src/lib.rs
+++ b/crates/ide_assists/src/lib.rs
@@ -17,6 +17,8 @@ mod tests;
 pub mod utils;
 pub mod ast_transform;
 
+use std::str::FromStr;
+
 use hir::Semantics;
 use ide_db::base_db::FileRange;
 use ide_db::{label::Label, source_change::SourceChange, RootDatabase};
@@ -56,6 +58,35 @@ impl AssistKind {
             _ => return false,
         }
     }
+
+    pub fn name(&self) -> &str {
+        match self {
+            AssistKind::None => "None",
+            AssistKind::QuickFix => "QuickFix",
+            AssistKind::Generate => "Generate",
+            AssistKind::Refactor => "Refactor",
+            AssistKind::RefactorExtract => "RefactorExtract",
+            AssistKind::RefactorInline => "RefactorInline",
+            AssistKind::RefactorRewrite => "RefactorRewrite",
+        }
+    }
+}
+
+impl FromStr for AssistKind {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "None" => Ok(AssistKind::None),
+            "QuickFix" => Ok(AssistKind::QuickFix),
+            "Generate" => Ok(AssistKind::Generate),
+            "Refactor" => Ok(AssistKind::Refactor),
+            "RefactorExtract" => Ok(AssistKind::RefactorExtract),
+            "RefactorInline" => Ok(AssistKind::RefactorInline),
+            "RefactorRewrite" => Ok(AssistKind::RefactorRewrite),
+            unknown => Err(format!("Unknown AssistKind: '{}'", unknown)),
+        }
+    }
 }
 
 /// Unique identifier of the assist, should not be shown to the user
@@ -63,6 +94,41 @@ impl AssistKind {
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct AssistId(pub &'static str, pub AssistKind);
 
+/// A way to control how many asssist to resolve during the assist resolution.
+/// When an assist is resolved, its edits are calculated that might be costly to always do by default.
+#[derive(Debug)]
+pub enum AssistResolveStrategy {
+    /// No assists should be resolved.
+    None,
+    /// All assists should be resolved.
+    All,
+    /// Only a certain assist should be resolved.
+    Single(SingleResolve),
+}
+
+/// Hold the [`AssistId`] data of a certain assist to resolve.
+/// The original id object cannot be used due to a `'static` lifetime
+/// and the requirement to construct this struct dynamically during the resolve handling.
+#[derive(Debug)]
+pub struct SingleResolve {
+    /// The id of the assist.
+    pub assist_id: String,
+    // The kind of the assist.
+    pub assist_kind: AssistKind,
+}
+
+impl AssistResolveStrategy {
+    pub fn should_resolve(&self, id: &AssistId) -> bool {
+        match self {
+            AssistResolveStrategy::None => false,
+            AssistResolveStrategy::All => true,
+            AssistResolveStrategy::Single(single_resolve) => {
+                single_resolve.assist_id == id.0 && single_resolve.assist_kind == id.1
+            }
+        }
+    }
+}
+
 #[derive(Clone, Debug)]
 pub struct GroupLabel(pub String);
 
@@ -91,7 +157,7 @@ impl Assist {
     pub fn get(
         db: &RootDatabase,
         config: &AssistConfig,
-        resolve: bool,
+        resolve: AssistResolveStrategy,
         range: FileRange,
     ) -> Vec<Assist> {
         let sema = Semantics::new(db);
diff --git a/crates/ide_assists/src/tests.rs b/crates/ide_assists/src/tests.rs
index 6f4f97361..9c2847998 100644
--- a/crates/ide_assists/src/tests.rs
+++ b/crates/ide_assists/src/tests.rs
@@ -12,7 +12,10 @@ use stdx::{format_to, trim_indent};
 use syntax::TextRange;
 use test_utils::{assert_eq_text, extract_offset};
 
-use crate::{handlers::Handler, Assist, AssistConfig, AssistContext, AssistKind, Assists};
+use crate::{
+    handlers::Handler, Assist, AssistConfig, AssistContext, AssistKind, AssistResolveStrategy,
+    Assists, SingleResolve,
+};
 
 pub(crate) const TEST_CONFIG: AssistConfig = AssistConfig {
     snippet_cap: SnippetCap::new(true),
@@ -65,14 +68,14 @@ fn check_doc_test(assist_id: &str, before: &str, after: &str) {
     let before = db.file_text(file_id).to_string();
     let frange = FileRange { file_id, range: selection.into() };
 
-    let assist = Assist::get(&db, &TEST_CONFIG, true, frange)
+    let assist = Assist::get(&db, &TEST_CONFIG, AssistResolveStrategy::All, frange)
         .into_iter()
         .find(|assist| assist.id.0 == assist_id)
         .unwrap_or_else(|| {
             panic!(
                 "\n\nAssist is not applicable: {}\nAvailable assists: {}",
                 assist_id,
-                Assist::get(&db, &TEST_CONFIG, false, frange)
+                Assist::get(&db, &TEST_CONFIG, AssistResolveStrategy::None, frange)
                     .into_iter()
                     .map(|assist| assist.id.0)
                     .collect::<Vec<_>>()
@@ -108,7 +111,7 @@ fn check(handler: Handler, before: &str, expected: ExpectedResult, assist_label:
     let sema = Semantics::new(&db);
     let config = TEST_CONFIG;
     let ctx = AssistContext::new(sema, &config, frange);
-    let mut acc = Assists::new(&ctx, true);
+    let mut acc = Assists::new(&ctx, AssistResolveStrategy::All);
     handler(&mut acc, &ctx);
     let mut res = acc.finish();
 
@@ -186,7 +189,7 @@ fn assist_order_field_struct() {
     let (before_cursor_pos, before) = extract_offset(before);
     let (db, file_id) = with_single_file(&before);
     let frange = FileRange { file_id, range: TextRange::empty(before_cursor_pos) };
-    let assists = Assist::get(&db, &TEST_CONFIG, false, frange);
+    let assists = Assist::get(&db, &TEST_CONFIG, AssistResolveStrategy::None, frange);
     let mut assists = assists.iter();
 
     assert_eq!(assists.next().expect("expected assist").label, "Change visibility to pub(crate)");
@@ -211,7 +214,7 @@ pub fn test_some_range(a: int) -> bool {
 "#,
     );
 
-    let assists = Assist::get(&db, &TEST_CONFIG, false, frange);
+    let assists = Assist::get(&db, &TEST_CONFIG, AssistResolveStrategy::None, frange);
     let expected = labels(&assists);
 
     expect![[r#"
@@ -240,7 +243,7 @@ pub fn test_some_range(a: int) -> bool {
         let mut cfg = TEST_CONFIG;
         cfg.allowed = Some(vec![AssistKind::Refactor]);
 
-        let assists = Assist::get(&db, &cfg, false, frange);
+        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::None, frange);
         let expected = labels(&assists);
 
         expect![[r#"
@@ -255,7 +258,7 @@ pub fn test_some_range(a: int) -> bool {
     {
         let mut cfg = TEST_CONFIG;
         cfg.allowed = Some(vec![AssistKind::RefactorExtract]);
-        let assists = Assist::get(&db, &cfg, false, frange);
+        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::None, frange);
         let expected = labels(&assists);
 
         expect![[r#"
@@ -268,9 +271,250 @@ pub fn test_some_range(a: int) -> bool {
     {
         let mut cfg = TEST_CONFIG;
         cfg.allowed = Some(vec![AssistKind::QuickFix]);
-        let assists = Assist::get(&db, &cfg, false, frange);
+        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::None, frange);
         let expected = labels(&assists);
 
         expect![[r#""#]].assert_eq(&expected);
     }
 }
+
+#[test]
+fn various_resolve_strategies() {
+    let (db, frange) = RootDatabase::with_range(
+        r#"
+pub fn test_some_range(a: int) -> bool {
+    if let 2..6 = $05$0 {
+        true
+    } else {
+        false
+    }
+}
+"#,
+    );
+
+    let mut cfg = TEST_CONFIG;
+    cfg.allowed = Some(vec![AssistKind::RefactorExtract]);
+
+    {
+        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::None, frange);
+        assert_eq!(2, assists.len());
+        let mut assists = assists.into_iter();
+
+        let extract_into_variable_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_variable",
+                    RefactorExtract,
+                ),
+                label: "Extract into variable",
+                group: None,
+                target: 59..60,
+                source_change: None,
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_variable_assist);
+
+        let extract_into_function_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_function",
+                    RefactorExtract,
+                ),
+                label: "Extract into function",
+                group: None,
+                target: 59..60,
+                source_change: None,
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_function_assist);
+    }
+
+    {
+        let assists = Assist::get(
+            &db,
+            &cfg,
+            AssistResolveStrategy::Single(SingleResolve {
+                assist_id: "SOMETHING_MISMATCHING".to_string(),
+                assist_kind: AssistKind::RefactorExtract,
+            }),
+            frange,
+        );
+        assert_eq!(2, assists.len());
+        let mut assists = assists.into_iter();
+
+        let extract_into_variable_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_variable",
+                    RefactorExtract,
+                ),
+                label: "Extract into variable",
+                group: None,
+                target: 59..60,
+                source_change: None,
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_variable_assist);
+
+        let extract_into_function_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_function",
+                    RefactorExtract,
+                ),
+                label: "Extract into function",
+                group: None,
+                target: 59..60,
+                source_change: None,
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_function_assist);
+    }
+
+    {
+        let assists = Assist::get(
+            &db,
+            &cfg,
+            AssistResolveStrategy::Single(SingleResolve {
+                assist_id: "extract_variable".to_string(),
+                assist_kind: AssistKind::RefactorExtract,
+            }),
+            frange,
+        );
+        assert_eq!(2, assists.len());
+        let mut assists = assists.into_iter();
+
+        let extract_into_variable_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_variable",
+                    RefactorExtract,
+                ),
+                label: "Extract into variable",
+                group: None,
+                target: 59..60,
+                source_change: Some(
+                    SourceChange {
+                        source_file_edits: {
+                            FileId(
+                                0,
+                            ): TextEdit {
+                                indels: [
+                                    Indel {
+                                        insert: "let $0var_name = 5;\n    ",
+                                        delete: 45..45,
+                                    },
+                                    Indel {
+                                        insert: "var_name",
+                                        delete: 59..60,
+                                    },
+                                ],
+                            },
+                        },
+                        file_system_edits: [],
+                        is_snippet: true,
+                    },
+                ),
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_variable_assist);
+
+        let extract_into_function_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_function",
+                    RefactorExtract,
+                ),
+                label: "Extract into function",
+                group: None,
+                target: 59..60,
+                source_change: None,
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_function_assist);
+    }
+
+    {
+        let assists = Assist::get(&db, &cfg, AssistResolveStrategy::All, frange);
+        assert_eq!(2, assists.len());
+        let mut assists = assists.into_iter();
+
+        let extract_into_variable_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_variable",
+                    RefactorExtract,
+                ),
+                label: "Extract into variable",
+                group: None,
+                target: 59..60,
+                source_change: Some(
+                    SourceChange {
+                        source_file_edits: {
+                            FileId(
+                                0,
+                            ): TextEdit {
+                                indels: [
+                                    Indel {
+                                        insert: "let $0var_name = 5;\n    ",
+                                        delete: 45..45,
+                                    },
+                                    Indel {
+                                        insert: "var_name",
+                                        delete: 59..60,
+                                    },
+                                ],
+                            },
+                        },
+                        file_system_edits: [],
+                        is_snippet: true,
+                    },
+                ),
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_variable_assist);
+
+        let extract_into_function_assist = assists.next().unwrap();
+        expect![[r#"
+            Assist {
+                id: AssistId(
+                    "extract_function",
+                    RefactorExtract,
+                ),
+                label: "Extract into function",
+                group: None,
+                target: 59..60,
+                source_change: Some(
+                    SourceChange {
+                        source_file_edits: {
+                            FileId(
+                                0,
+                            ): TextEdit {
+                                indels: [
+                                    Indel {
+                                        insert: "fun_name()",
+                                        delete: 59..60,
+                                    },
+                                    Indel {
+                                        insert: "\n\nfn $0fun_name() -> i32 {\n    5\n}",
+                                        delete: 110..110,
+                                    },
+                                ],
+                            },
+                        },
+                        file_system_edits: [],
+                        is_snippet: true,
+                    },
+                ),
+            }
+        "#]]
+        .assert_debug_eq(&extract_into_function_assist);
+    }
+}
diff --git a/crates/ide_assists/src/utils/suggest_name.rs b/crates/ide_assists/src/utils/suggest_name.rs
index 533624c1f..deafcd630 100644
--- a/crates/ide_assists/src/utils/suggest_name.rs
+++ b/crates/ide_assists/src/utils/suggest_name.rs
@@ -227,7 +227,7 @@ fn name_of_type(ty: &hir::Type, db: &RootDatabase) -> Option<String> {
         let name = adt.name(db).to_string();
 
         if WRAPPER_TYPES.contains(&name.as_str()) {
-            let inner_ty = ty.type_parameters().next()?;
+            let inner_ty = ty.type_arguments().next()?;
             return name_of_type(&inner_ty, db);
         }
 
diff --git a/crates/ide_completion/src/completions.rs b/crates/ide_completion/src/completions.rs
index e2994eed4..78154bf3e 100644
--- a/crates/ide_completion/src/completions.rs
+++ b/crates/ide_completion/src/completions.rs
@@ -203,41 +203,37 @@ impl Completions {
 fn complete_enum_variants(
     acc: &mut Completions,
     ctx: &CompletionContext,
-    ty: &hir::Type,
+    enum_data: hir::Enum,
     cb: impl Fn(&mut Completions, &CompletionContext, hir::Variant, hir::ModPath),
 ) {
-    if let Some(hir::Adt::Enum(enum_data)) =
-        iter::successors(Some(ty.clone()), |ty| ty.remove_ref()).last().and_then(|ty| ty.as_adt())
-    {
-        let variants = enum_data.variants(ctx.db);
-
-        let module = if let Some(module) = ctx.scope.module() {
-            // Compute path from the completion site if available.
-            module
-        } else {
-            // Otherwise fall back to the enum's definition site.
-            enum_data.module(ctx.db)
-        };
-
-        if let Some(impl_) = ctx.impl_def.as_ref().and_then(|impl_| ctx.sema.to_def(impl_)) {
-            if impl_.self_ty(ctx.db) == *ty {
-                for &variant in &variants {
-                    let self_path = hir::ModPath::from_segments(
-                        hir::PathKind::Plain,
-                        iter::once(known::SELF_TYPE).chain(iter::once(variant.name(ctx.db))),
-                    );
-                    cb(acc, ctx, variant, self_path);
-                }
+    let variants = enum_data.variants(ctx.db);
+
+    let module = if let Some(module) = ctx.scope.module() {
+        // Compute path from the completion site if available.
+        module
+    } else {
+        // Otherwise fall back to the enum's definition site.
+        enum_data.module(ctx.db)
+    };
+
+    if let Some(impl_) = ctx.impl_def.as_ref().and_then(|impl_| ctx.sema.to_def(impl_)) {
+        if impl_.self_ty(ctx.db).as_adt() == Some(hir::Adt::Enum(enum_data)) {
+            for &variant in &variants {
+                let self_path = hir::ModPath::from_segments(
+                    hir::PathKind::Plain,
+                    iter::once(known::SELF_TYPE).chain(iter::once(variant.name(ctx.db))),
+                );
+                cb(acc, ctx, variant, self_path);
             }
         }
+    }
 
-        for variant in variants {
-            if let Some(path) = module.find_use_path(ctx.db, hir::ModuleDef::from(variant)) {
-                // Variants with trivial paths are already added by the existing completion logic,
-                // so we should avoid adding these twice
-                if path.segments().len() > 1 {
-                    cb(acc, ctx, variant, path);
-                }
+    for variant in variants {
+        if let Some(path) = module.find_use_path(ctx.db, hir::ModuleDef::from(variant)) {
+            // Variants with trivial paths are already added by the existing completion logic,
+            // so we should avoid adding these twice
+            if path.segments().len() > 1 {
+                cb(acc, ctx, variant, path);
             }
         }
     }
diff --git a/crates/ide_completion/src/completions/pattern.rs b/crates/ide_completion/src/completions/pattern.rs
index 808d7ff7e..8dc9ab73c 100644
--- a/crates/ide_completion/src/completions/pattern.rs
+++ b/crates/ide_completion/src/completions/pattern.rs
@@ -12,8 +12,10 @@ pub(crate) fn complete_pattern(acc: &mut Completions, ctx: &CompletionContext) {
     }
 
     if !ctx.is_irrefutable_pat_binding {
-        if let Some(ty) = ctx.expected_type.as_ref() {
-            super::complete_enum_variants(acc, ctx, ty, |acc, ctx, variant, path| {
+        if let Some(hir::Adt::Enum(e)) =
+            ctx.expected_type.as_ref().and_then(|ty| ty.strip_references().as_adt())
+        {
+            super::complete_enum_variants(acc, ctx, e, |acc, ctx, variant, path| {
                 acc.add_qualified_variant_pat(ctx, variant, path.clone());
                 acc.add_qualified_enum_variant(ctx, variant, path);
             });
diff --git a/crates/ide_completion/src/completions/postfix.rs b/crates/ide_completion/src/completions/postfix.rs
index ac69b720a..962aaf0df 100644
--- a/crates/ide_completion/src/completions/postfix.rs
+++ b/crates/ide_completion/src/completions/postfix.rs
@@ -35,14 +35,11 @@ pub(crate) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
         None => return,
     };
 
-    let ref_removed_ty =
-        std::iter::successors(Some(receiver_ty.clone()), |ty| ty.remove_ref()).last().unwrap();
-
     let cap = match ctx.config.snippet_cap {
         Some(it) => it,
         None => return,
     };
-    let try_enum = TryEnum::from_ty(&ctx.sema, &ref_removed_ty);
+    let try_enum = TryEnum::from_ty(&ctx.sema, &receiver_ty.strip_references());
     if let Some(try_enum) = &try_enum {
         match try_enum {
             TryEnum::Result => {
diff --git a/crates/ide_completion/src/completions/postfix/format_like.rs b/crates/ide_completion/src/completions/postfix/format_like.rs
index e86ffa8f8..0dcb3e898 100644
--- a/crates/ide_completion/src/completions/postfix/format_like.rs
+++ b/crates/ide_completion/src/completions/postfix/format_like.rs
@@ -1,4 +1,4 @@
-// Feature: Format String Completion.
+// Feature: Format String Completion
 //
 // `"Result {result} is {2 + 2}"` is expanded to the `"Result {} is {}", result, 2 + 2`.
 //
diff --git a/crates/ide_completion/src/completions/qualified_path.rs b/crates/ide_completion/src/completions/qualified_path.rs
index 969249df6..eedb44873 100644
--- a/crates/ide_completion/src/completions/qualified_path.rs
+++ b/crates/ide_completion/src/completions/qualified_path.rs
@@ -52,18 +52,24 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
         | PathResolution::Def(def @ hir::ModuleDef::TypeAlias(_))
         | PathResolution::Def(def @ hir::ModuleDef::BuiltinType(_)) => {
             if let hir::ModuleDef::Adt(Adt::Enum(e)) = def {
-                for variant in e.variants(ctx.db) {
-                    acc.add_enum_variant(ctx, variant, None);
-                }
+                add_enum_variants(ctx, acc, e);
             }
             let ty = match def {
                 hir::ModuleDef::Adt(adt) => adt.ty(ctx.db),
-                hir::ModuleDef::TypeAlias(a) => a.ty(ctx.db),
+                hir::ModuleDef::TypeAlias(a) => {
+                    let ty = a.ty(ctx.db);
+                    if let Some(Adt::Enum(e)) = ty.as_adt() {
+                        cov_mark::hit!(completes_variant_through_alias);
+                        add_enum_variants(ctx, acc, e);
+                    }
+                    ty
+                }
                 hir::ModuleDef::BuiltinType(builtin) => {
                     let module = match ctx.scope.module() {
                         Some(it) => it,
                         None => return,
                     };
+                    cov_mark::hit!(completes_primitive_assoc_const);
                     builtin.ty(ctx.db, module)
                 }
                 _ => unreachable!(),
@@ -92,9 +98,8 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                     if context_module.map_or(false, |m| !item.is_visible_from(ctx.db, m)) {
                         return None;
                     }
-                    match item {
-                        hir::AssocItem::Function(_) | hir::AssocItem::Const(_) => {}
-                        hir::AssocItem::TypeAlias(ty) => acc.add_type_alias(ctx, ty),
+                    if let hir::AssocItem::TypeAlias(ty) = item {
+                        acc.add_type_alias(ctx, ty)
                     }
                     None::<()>
                 });
@@ -122,9 +127,7 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                 };
 
                 if let Some(Adt::Enum(e)) = ty.as_adt() {
-                    for variant in e.variants(ctx.db) {
-                        acc.add_enum_variant(ctx, variant, None);
-                    }
+                    add_enum_variants(ctx, acc, e);
                 }
 
                 let traits_in_scope = ctx.scope.traits_in_scope();
@@ -151,6 +154,12 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
     }
 }
 
+fn add_enum_variants(ctx: &CompletionContext, acc: &mut Completions, e: hir::Enum) {
+    for variant in e.variants(ctx.db) {
+        acc.add_enum_variant(ctx, variant, None);
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use expect_test::{expect, Expect};
@@ -737,29 +746,7 @@ fn f() {}
     }
 
     #[test]
-    fn completes_function() {
-        check(
-            r#"
-fn foo(
-    a: i32,
-    b: i32
-) {
-
-}
-
-fn main() {
-    fo$0
-}
-"#,
-            expect![[r#"
-                fn main() fn()
-                fn foo(…) fn(i32, i32)
-            "#]],
-        );
-    }
-
-    #[test]
-    fn completes_self_enum() {
+    fn completes_variant_through_self() {
         check(
             r#"
 enum Foo {
@@ -783,6 +770,7 @@ impl Foo {
 
     #[test]
     fn completes_primitive_assoc_const() {
+        cov_mark::check!(completes_primitive_assoc_const);
         check(
             r#"
 //- /lib.rs crate:lib deps:core
@@ -804,4 +792,23 @@ impl u8 {
             "#]],
         );
     }
+
+    #[test]
+    fn completes_variant_through_alias() {
+        cov_mark::check!(completes_variant_through_alias);
+        check(
+            r#"
+enum Foo {
+    Bar
+}
+type Foo2 = Foo;
+fn main() {
+    Foo2::$0
+}
+"#,
+            expect![[r#"
+                ev Bar ()
+            "#]],
+        );
+    }
 }
diff --git a/crates/ide_completion/src/completions/unqualified_path.rs b/crates/ide_completion/src/completions/unqualified_path.rs
index 1b8b063e7..7875500c1 100644
--- a/crates/ide_completion/src/completions/unqualified_path.rs
+++ b/crates/ide_completion/src/completions/unqualified_path.rs
@@ -17,8 +17,10 @@ pub(crate) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionC
         return;
     }
 
-    if let Some(ty) = &ctx.expected_type {
-        super::complete_enum_variants(acc, ctx, ty, |acc, ctx, variant, path| {
+    if let Some(hir::Adt::Enum(e)) =
+        ctx.expected_type.as_ref().and_then(|ty| ty.strip_references().as_adt())
+    {
+        super::complete_enum_variants(acc, ctx, e, |acc, ctx, variant, path| {
             acc.add_qualified_enum_variant(ctx, variant, path)
         });
     }
diff --git a/crates/ide_completion/src/context.rs b/crates/ide_completion/src/context.rs
index 32f81aec1..f3fcb712c 100644
--- a/crates/ide_completion/src/context.rs
+++ b/crates/ide_completion/src/context.rs
@@ -301,103 +301,108 @@ impl<'a> CompletionContext<'a> {
             .find_map(ast::Impl::cast);
     }
 
+    fn expected_type_and_name(&self) -> (Option<Type>, Option<NameOrNameRef>) {
+        let mut node = match self.token.parent() {
+            Some(it) => it,
+            None => return (None, None),
+        };
+        loop {
+            break match_ast! {
+                match node {
+                    ast::LetStmt(it) => {
+                        cov_mark::hit!(expected_type_let_with_leading_char);
+                        cov_mark::hit!(expected_type_let_without_leading_char);
+                        let ty = it.pat()
+                            .and_then(|pat| self.sema.type_of_pat(&pat));
+                        let name = if let Some(ast::Pat::IdentPat(ident)) = it.pat() {
+                            ident.name().map(NameOrNameRef::Name)
+                        } else {
+                            None
+                        };
+
+                        (ty, name)
+                    },
+                    ast::ArgList(_it) => {
+                        cov_mark::hit!(expected_type_fn_param_with_leading_char);
+                        cov_mark::hit!(expected_type_fn_param_without_leading_char);
+                        ActiveParameter::at_token(
+                            &self.sema,
+                            self.token.clone(),
+                        ).map(|ap| {
+                            let name = ap.ident().map(NameOrNameRef::Name);
+                            (Some(ap.ty), name)
+                        })
+                        .unwrap_or((None, None))
+                    },
+                    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),
+                            ))
+                            .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))
+                    },
+                    ast::MatchExpr(it) => {
+                        cov_mark::hit!(expected_type_match_arm_without_leading_char);
+                        let ty = it.expr()
+                            .and_then(|e| self.sema.type_of_expr(&e));
+                        (ty, None)
+                    },
+                    ast::IfExpr(it) => {
+                        cov_mark::hit!(expected_type_if_let_without_leading_char);
+                        let ty = it.condition()
+                            .and_then(|cond| cond.expr())
+                            .and_then(|e| self.sema.type_of_expr(&e));
+                        (ty, None)
+                    },
+                    ast::IdentPat(it) => {
+                        cov_mark::hit!(expected_type_if_let_with_leading_char);
+                        cov_mark::hit!(expected_type_match_arm_with_leading_char);
+                        let ty = self.sema.type_of_pat(&ast::Pat::from(it));
+                        (ty, None)
+                    },
+                    ast::Fn(it) => {
+                        cov_mark::hit!(expected_type_fn_ret_with_leading_char);
+                        cov_mark::hit!(expected_type_fn_ret_without_leading_char);
+                        let def = self.sema.to_def(&it);
+                        (def.map(|def| def.ret_type(self.db)), None)
+                    },
+                    ast::Stmt(it) => (None, None),
+                    _ => {
+                        match node.parent() {
+                            Some(n) => {
+                                node = n;
+                                continue;
+                            },
+                            None => (None, None),
+                        }
+                    },
+                }
+            };
+        }
+    }
+
     fn fill(
         &mut self,
         original_file: &SyntaxNode,
         file_with_fake_ident: SyntaxNode,
         offset: TextSize,
     ) {
-        let (expected_type, expected_name) = {
-            let mut node = match self.token.parent() {
-                Some(it) => it,
-                None => return,
-            };
-            loop {
-                break match_ast! {
-                    match node {
-                        ast::LetStmt(it) => {
-                            cov_mark::hit!(expected_type_let_with_leading_char);
-                            cov_mark::hit!(expected_type_let_without_leading_char);
-                            let ty = it.pat()
-                                .and_then(|pat| self.sema.type_of_pat(&pat));
-                            let name = if let Some(ast::Pat::IdentPat(ident)) = it.pat() {
-                                ident.name().map(NameOrNameRef::Name)
-                            } else {
-                                None
-                            };
-
-                            (ty, name)
-                        },
-                        ast::ArgList(_it) => {
-                            cov_mark::hit!(expected_type_fn_param_with_leading_char);
-                            cov_mark::hit!(expected_type_fn_param_without_leading_char);
-                            ActiveParameter::at_token(
-                                &self.sema,
-                                self.token.clone(),
-                            ).map(|ap| {
-                                let name = ap.ident().map(NameOrNameRef::Name);
-                                (Some(ap.ty), name)
-                            })
-                            .unwrap_or((None, None))
-                        },
-                        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.signature_ty(self.db)),
-                                    rf.field_name().map(NameOrNameRef::NameRef),
-                                ))
-                                .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.signature_ty(self.db)),
-                                    it.field_name().map(NameOrNameRef::NameRef),
-                                ))
-                                .unwrap_or((None, None))
-                        },
-                        ast::MatchExpr(it) => {
-                            cov_mark::hit!(expected_type_match_arm_without_leading_char);
-                            let ty = it.expr()
-                                .and_then(|e| self.sema.type_of_expr(&e));
-
-                            (ty, None)
-                        },
-                        ast::IdentPat(it) => {
-                            cov_mark::hit!(expected_type_if_let_with_leading_char);
-                            cov_mark::hit!(expected_type_match_arm_with_leading_char);
-                            let ty = self.sema.type_of_pat(&ast::Pat::from(it));
-
-                            (ty, None)
-                        },
-                        ast::Fn(_it) => {
-                            cov_mark::hit!(expected_type_fn_ret_with_leading_char);
-                            cov_mark::hit!(expected_type_fn_ret_without_leading_char);
-                            let ty = self.token.ancestors()
-                                .find_map(|ancestor| ast::Expr::cast(ancestor))
-                                .and_then(|expr| self.sema.type_of_expr(&expr));
-
-                            (ty, None)
-                        },
-                        _ => {
-                            match node.parent() {
-                                Some(n) => {
-                                    node = n;
-                                    continue;
-                                },
-                                None => (None, None),
-                            }
-                        },
-                    }
-                };
-            }
-        };
+        let (expected_type, expected_name) = self.expected_type_and_name();
         self.expected_type = expected_type;
         self.expected_name = expected_name;
         self.attribute_under_caret = find_node_at_offset(&file_with_fake_ident, offset);
@@ -802,6 +807,7 @@ fn foo() {
 
     #[test]
     fn expected_type_if_let_without_leading_char() {
+        cov_mark::check!(expected_type_if_let_without_leading_char);
         check_expected_type_and_name(
             r#"
 enum Foo { Bar, Baz, Quux }
@@ -811,8 +817,8 @@ fn foo() {
     if let $0 = f { }
 }
 "#,
-            expect![[r#"ty: (), name: ?"#]],
-        ) // FIXME should be `ty: u32, name: ?`
+            expect![[r#"ty: Foo, name: ?"#]],
+        )
     }
 
     #[test]
@@ -840,8 +846,8 @@ fn foo() -> u32 {
     $0
 }
 "#,
-            expect![[r#"ty: (), name: ?"#]],
-        ) // FIXME this should be `ty: u32, name: ?`
+            expect![[r#"ty: u32, name: ?"#]],
+        )
     }
 
     #[test]
@@ -856,4 +862,16 @@ fn foo() -> u32 {
             expect![[r#"ty: u32, name: ?"#]],
         )
     }
+
+    #[test]
+    fn expected_type_fn_ret_fn_ref_fully_typed() {
+        check_expected_type_and_name(
+            r#"
+fn foo() -> u32 {
+    foo$0
+}
+"#,
+            expect![[r#"ty: u32, name: ?"#]],
+        )
+    }
 }
diff --git a/crates/ide_completion/src/render/enum_variant.rs b/crates/ide_completion/src/render/enum_variant.rs
index 832f5ced1..0c0c71134 100644
--- a/crates/ide_completion/src/render/enum_variant.rs
+++ b/crates/ide_completion/src/render/enum_variant.rs
@@ -93,7 +93,7 @@ impl<'a> EnumRender<'a> {
             .variant
             .fields(self.ctx.db())
             .into_iter()
-            .map(|field| (field.name(self.ctx.db()), field.signature_ty(self.ctx.db())));
+            .map(|field| (field.name(self.ctx.db()), field.ty(self.ctx.db())));
 
         match self.variant_kind {
             StructKind::Tuple | StructKind::Unit => format!(
diff --git a/crates/proc_macro_api/Cargo.toml b/crates/proc_macro_api/Cargo.toml
index 1ba1e4abd..2ce5eeedd 100644
--- a/crates/proc_macro_api/Cargo.toml
+++ b/crates/proc_macro_api/Cargo.toml
@@ -15,7 +15,7 @@ serde_json = { version = "1.0", features = ["unbounded_depth"] }
 log = "0.4.8"
 crossbeam-channel = "0.5.0"
 jod-thread = "0.1.1"
-memmap = "0.7.0"
+memmap2 = "0.2.0"
 object = { version = "0.23.0", default-features = false, features = ["std", "read_core", "elf", "macho", "pe", "unaligned"] }
 snap = "1.0"
 
diff --git a/crates/proc_macro_api/src/version.rs b/crates/proc_macro_api/src/version.rs
index dcf8fae8f..6dbac50b4 100644
--- a/crates/proc_macro_api/src/version.rs
+++ b/crates/proc_macro_api/src/version.rs
@@ -6,7 +6,7 @@ use std::{
     path::Path,
 };
 
-use memmap::Mmap;
+use memmap2::Mmap;
 use object::read::{File as BinaryFile, Object, ObjectSection};
 use snap::read::FrameDecoder as SnapDecoder;
 
diff --git a/crates/rust-analyzer/src/benchmarks.rs b/crates/rust-analyzer/src/benchmarks.rs
deleted file mode 100644
index bdd94b1c4..000000000
--- a/crates/rust-analyzer/src/benchmarks.rs
+++ /dev/null
@@ -1,74 +0,0 @@
-//! Fully integrated benchmarks for rust-analyzer, which load real cargo
-//! projects.
-//!
-//! The benchmark here is used to debug specific performance regressions. If you
-//! notice that, eg, completion is slow in some specific case, you can  modify
-//! code here exercise this specific completion, and thus have a fast
-//! edit/compile/test cycle.
-//!
-//! Note that "Rust Analyzer: Run" action does not allow running a single test
-//! in release mode in VS Code. There's however "Rust Analyzer: Copy Run Command Line"
-//! which you can use to paste the command in terminal and add `--release` manually.
-
-use std::sync::Arc;
-
-use ide::Change;
-use test_utils::project_root;
-use vfs::{AbsPathBuf, VfsPath};
-
-use crate::cli::load_cargo::{load_workspace_at, LoadCargoConfig};
-
-#[test]
-fn benchmark_integrated_highlighting() {
-    // Don't run slow benchmark by default
-    if true {
-        return;
-    }
-
-    // Load rust-analyzer itself.
-    let workspace_to_load = project_root();
-    let file = "./crates/ide_db/src/apply_change.rs";
-
-    let cargo_config = Default::default();
-    let load_cargo_config = LoadCargoConfig {
-        load_out_dirs_from_check: true,
-        wrap_rustc: false,
-        with_proc_macro: false,
-    };
-
-    let (mut host, vfs, _proc_macro) = {
-        let _it = stdx::timeit("workspace loading");
-        load_workspace_at(&workspace_to_load, &cargo_config, &load_cargo_config, &|_| {}).unwrap()
-    };
-
-    let file_id = {
-        let file = workspace_to_load.join(file);
-        let path = VfsPath::from(AbsPathBuf::assert(file));
-        vfs.file_id(&path).unwrap_or_else(|| panic!("can't find virtual file for {}", path))
-    };
-
-    {
-        let _it = stdx::timeit("initial");
-        let analysis = host.analysis();
-        analysis.highlight_as_html(file_id, false).unwrap();
-    }
-
-    profile::init_from("*>100");
-    // let _s = profile::heartbeat_span();
-
-    {
-        let _it = stdx::timeit("change");
-        let mut text = host.analysis().file_text(file_id).unwrap().to_string();
-        text.push_str("\npub fn _dummy() {}\n");
-        let mut change = Change::new();
-        change.change_file(file_id, Some(Arc::new(text)));
-        host.apply_change(change);
-    }
-
-    {
-        let _it = stdx::timeit("after change");
-        let _span = profile::cpu_span();
-        let analysis = host.analysis();
-        analysis.highlight_as_html(file_id, false).unwrap();
-    }
-}
diff --git a/crates/rust-analyzer/src/cli/diagnostics.rs b/crates/rust-analyzer/src/cli/diagnostics.rs
index 74f784338..c33c8179c 100644
--- a/crates/rust-analyzer/src/cli/diagnostics.rs
+++ b/crates/rust-analyzer/src/cli/diagnostics.rs
@@ -7,7 +7,7 @@ use anyhow::anyhow;
 use rustc_hash::FxHashSet;
 
 use hir::{db::HirDatabase, Crate, Module};
-use ide::{DiagnosticsConfig, Severity};
+use ide::{AssistResolveStrategy, DiagnosticsConfig, Severity};
 use ide_db::base_db::SourceDatabaseExt;
 
 use crate::cli::{
@@ -57,8 +57,9 @@ pub fn diagnostics(
             let crate_name =
                 module.krate().display_name(db).as_deref().unwrap_or("unknown").to_string();
             println!("processing crate: {}, module: {}", crate_name, _vfs.file_path(file_id));
-            for diagnostic in
-                analysis.diagnostics(&DiagnosticsConfig::default(), false, file_id).unwrap()
+            for diagnostic in analysis
+                .diagnostics(&DiagnosticsConfig::default(), AssistResolveStrategy::None, file_id)
+                .unwrap()
             {
                 if matches!(diagnostic.severity, Severity::Error) {
                     found_error = true;
diff --git a/crates/rust-analyzer/src/global_state.rs b/crates/rust-analyzer/src/global_state.rs
index adeb7a97e..6f2f482c1 100644
--- a/crates/rust-analyzer/src/global_state.rs
+++ b/crates/rust-analyzer/src/global_state.rs
@@ -84,6 +84,7 @@ pub(crate) struct GlobalState {
     pub(crate) workspace_build_data: Option<BuildDataResult>,
     pub(crate) fetch_build_data_queue:
         OpQueue<BuildDataCollector, Option<anyhow::Result<BuildDataResult>>>,
+    pub(crate) prime_caches_queue: OpQueue<(), ()>,
 
     latest_requests: Arc<RwLock<LatestRequests>>,
 }
@@ -146,6 +147,7 @@ impl GlobalState {
             workspaces: Arc::new(Vec::new()),
             fetch_workspaces_queue: OpQueue::default(),
             workspace_build_data: None,
+            prime_caches_queue: OpQueue::default(),
 
             fetch_build_data_queue: OpQueue::default(),
             latest_requests: Default::default(),
diff --git a/crates/rust-analyzer/src/handlers.rs b/crates/rust-analyzer/src/handlers.rs
index 1f59402e5..f6e40f872 100644
--- a/crates/rust-analyzer/src/handlers.rs
+++ b/crates/rust-analyzer/src/handlers.rs
@@ -8,8 +8,9 @@ use std::{
 };
 
 use ide::{
-    AnnotationConfig, FileId, FilePosition, FileRange, HoverAction, HoverGotoTypeData, Query,
-    RangeInfo, Runnable, RunnableKind, SearchScope, SourceChange, TextEdit,
+    AnnotationConfig, AssistKind, AssistResolveStrategy, FileId, FilePosition, FileRange,
+    HoverAction, HoverGotoTypeData, Query, RangeInfo, Runnable, RunnableKind, SearchScope,
+    SingleResolve, SourceChange, TextEdit,
 };
 use ide_db::SymbolKind;
 use itertools::Itertools;
@@ -27,7 +28,7 @@ use lsp_types::{
 use project_model::TargetKind;
 use serde::{Deserialize, Serialize};
 use serde_json::to_value;
-use stdx::{format_to, split_once};
+use stdx::format_to;
 use syntax::{algo, ast, AstNode, TextRange, TextSize};
 
 use crate::{
@@ -1004,10 +1005,15 @@ pub(crate) fn handle_code_action(
     let mut res: Vec<lsp_ext::CodeAction> = Vec::new();
 
     let code_action_resolve_cap = snap.config.code_action_resolve();
+    let resolve = if code_action_resolve_cap {
+        AssistResolveStrategy::None
+    } else {
+        AssistResolveStrategy::All
+    };
     let assists = snap.analysis.assists_with_fixes(
         &assists_config,
         &snap.config.diagnostics(),
-        !code_action_resolve_cap,
+        resolve,
         frange,
     )?;
     for (index, assist) in assists.into_iter().enumerate() {
@@ -1052,22 +1058,68 @@ pub(crate) fn handle_code_action_resolve(
         .only
         .map(|it| it.into_iter().filter_map(from_proto::assist_kind).collect());
 
+    let (assist_index, assist_resolve) = match parse_action_id(&params.id) {
+        Ok(parsed_data) => parsed_data,
+        Err(e) => {
+            return Err(LspError::new(
+                ErrorCode::InvalidParams as i32,
+                format!("Failed to parse action id string '{}': {}", params.id, e),
+            )
+            .into())
+        }
+    };
+
+    let expected_assist_id = assist_resolve.assist_id.clone();
+    let expected_kind = assist_resolve.assist_kind;
+
     let assists = snap.analysis.assists_with_fixes(
         &assists_config,
         &snap.config.diagnostics(),
-        true,
+        AssistResolveStrategy::Single(assist_resolve),
         frange,
     )?;
 
-    let (id, index) = split_once(&params.id, ':').unwrap();
-    let index = index.parse::<usize>().unwrap();
-    let assist = &assists[index];
-    assert!(assist.id.0 == id);
+    let assist = match assists.get(assist_index) {
+        Some(assist) => assist,
+        None => return Err(LspError::new(
+            ErrorCode::InvalidParams as i32,
+            format!(
+                "Failed to find the assist for index {} provided by the resolve request. Resolve request assist id: {}",
+                assist_index, params.id,
+            ),
+        )
+        .into())
+    };
+    if assist.id.0 != expected_assist_id || assist.id.1 != expected_kind {
+        return Err(LspError::new(
+            ErrorCode::InvalidParams as i32,
+            format!(
+                "Mismatching assist at index {} for the resolve parameters given. Resolve request assist id: {}, actual id: {:?}.",
+                assist_index, params.id, assist.id
+            ),
+        )
+        .into());
+    }
     let edit = to_proto::code_action(&snap, assist.clone(), None)?.edit;
     code_action.edit = edit;
     Ok(code_action)
 }
 
+fn parse_action_id(action_id: &str) -> Result<(usize, SingleResolve), String> {
+    let id_parts = action_id.split(':').collect_vec();
+    match id_parts.as_slice() {
+        &[assist_id_string, assist_kind_string, index_string] => {
+            let assist_kind: AssistKind = assist_kind_string.parse()?;
+            let index: usize = match index_string.parse() {
+                Ok(index) => index,
+                Err(e) => return Err(format!("Incorrect index string: {}", e)),
+            };
+            Ok((index, SingleResolve { assist_id: assist_id_string.to_string(), assist_kind }))
+        }
+        _ => Err("Action id contains incorrect number of segments".to_string()),
+    }
+}
+
 pub(crate) fn handle_code_lens(
     snap: GlobalStateSnapshot,
     params: lsp_types::CodeLensParams,
@@ -1182,7 +1234,7 @@ pub(crate) fn publish_diagnostics(
 
     let diagnostics: Vec<Diagnostic> = snap
         .analysis
-        .diagnostics(&snap.config.diagnostics(), false, file_id)?
+        .diagnostics(&snap.config.diagnostics(), AssistResolveStrategy::None, file_id)?
         .into_iter()
         .map(|d| Diagnostic {
             range: to_proto::range(&line_index, d.range),
diff --git a/crates/rust-analyzer/src/integrated_benchmarks.rs b/crates/rust-analyzer/src/integrated_benchmarks.rs
new file mode 100644
index 000000000..3dcbe397a
--- /dev/null
+++ b/crates/rust-analyzer/src/integrated_benchmarks.rs
@@ -0,0 +1,184 @@
+//! Fully integrated benchmarks for rust-analyzer, which load real cargo
+//! projects.
+//!
+//! The benchmark here is used to debug specific performance regressions. If you
+//! notice that, eg, completion is slow in some specific case, you can  modify
+//! code here exercise this specific completion, and thus have a fast
+//! edit/compile/test cycle.
+//!
+//! Note that "Rust Analyzer: Run" action does not allow running a single test
+//! in release mode in VS Code. There's however "Rust Analyzer: Copy Run Command Line"
+//! which you can use to paste the command in terminal and add `--release` manually.
+
+use std::{convert::TryFrom, sync::Arc};
+
+use ide::{Change, CompletionConfig, FilePosition, TextSize};
+use ide_db::helpers::{insert_use::InsertUseConfig, merge_imports::MergeBehavior, SnippetCap};
+use test_utils::project_root;
+use vfs::{AbsPathBuf, VfsPath};
+
+use crate::cli::load_cargo::{load_workspace_at, LoadCargoConfig};
+
+#[test]
+fn integrated_highlighting_benchmark() {
+    if std::env::var("RUN_SLOW_BENCHES").is_err() {
+        return;
+    }
+
+    // Load rust-analyzer itself.
+    let workspace_to_load = project_root();
+    let file = "./crates/ide_db/src/apply_change.rs";
+
+    let cargo_config = Default::default();
+    let load_cargo_config = LoadCargoConfig {
+        load_out_dirs_from_check: true,
+        wrap_rustc: false,
+        with_proc_macro: false,
+    };
+
+    let (mut host, vfs, _proc_macro) = {
+        let _it = stdx::timeit("workspace loading");
+        load_workspace_at(&workspace_to_load, &cargo_config, &load_cargo_config, &|_| {}).unwrap()
+    };
+
+    let file_id = {
+        let file = workspace_to_load.join(file);
+        let path = VfsPath::from(AbsPathBuf::assert(file));
+        vfs.file_id(&path).unwrap_or_else(|| panic!("can't find virtual file for {}", path))
+    };
+
+    {
+        let _it = stdx::timeit("initial");
+        let analysis = host.analysis();
+        analysis.highlight_as_html(file_id, false).unwrap();
+    }
+
+    profile::init_from("*>100");
+    // let _s = profile::heartbeat_span();
+
+    {
+        let _it = stdx::timeit("change");
+        let mut text = host.analysis().file_text(file_id).unwrap().to_string();
+        text.push_str("\npub fn _dummy() {}\n");
+        let mut change = Change::new();
+        change.change_file(file_id, Some(Arc::new(text)));
+        host.apply_change(change);
+    }
+
+    {
+        let _it = stdx::timeit("after change");
+        let _span = profile::cpu_span();
+        let analysis = host.analysis();
+        analysis.highlight_as_html(file_id, false).unwrap();
+    }
+}
+
+#[test]
+fn integrated_completion_benchmark() {
+    if std::env::var("RUN_SLOW_BENCHES").is_err() {
+        return;
+    }
+
+    // Load rust-analyzer itself.
+    let workspace_to_load = project_root();
+    let file = "./crates/hir/src/lib.rs";
+
+    let cargo_config = Default::default();
+    let load_cargo_config = LoadCargoConfig {
+        load_out_dirs_from_check: true,
+        wrap_rustc: false,
+        with_proc_macro: false,
+    };
+
+    let (mut host, vfs, _proc_macro) = {
+        let _it = stdx::timeit("workspace loading");
+        load_workspace_at(&workspace_to_load, &cargo_config, &load_cargo_config, &|_| {}).unwrap()
+    };
+
+    let file_id = {
+        let file = workspace_to_load.join(file);
+        let path = VfsPath::from(AbsPathBuf::assert(file));
+        vfs.file_id(&path).unwrap_or_else(|| panic!("can't find virtual file for {}", path))
+    };
+
+    {
+        let _it = stdx::timeit("initial");
+        let analysis = host.analysis();
+        analysis.highlight_as_html(file_id, false).unwrap();
+    }
+
+    profile::init_from("*>5");
+    // let _s = profile::heartbeat_span();
+
+    let completion_offset = {
+        let _it = stdx::timeit("change");
+        let mut text = host.analysis().file_text(file_id).unwrap().to_string();
+        let completion_offset =
+            patch(&mut text, "db.struct_data(self.id)", "sel;\ndb.struct_data(self.id)")
+                + "sel".len();
+        let mut change = Change::new();
+        change.change_file(file_id, Some(Arc::new(text)));
+        host.apply_change(change);
+        completion_offset
+    };
+
+    {
+        let _it = stdx::timeit("unqualified path completion");
+        let _span = profile::cpu_span();
+        let analysis = host.analysis();
+        let config = CompletionConfig {
+            enable_postfix_completions: true,
+            enable_imports_on_the_fly: true,
+            add_call_parenthesis: true,
+            add_call_argument_snippets: true,
+            snippet_cap: SnippetCap::new(true),
+            insert_use: InsertUseConfig {
+                merge: Some(MergeBehavior::Full),
+                prefix_kind: hir::PrefixKind::ByCrate,
+                group: true,
+            },
+        };
+        let position =
+            FilePosition { file_id, offset: TextSize::try_from(completion_offset).unwrap() };
+        analysis.completions(&config, position).unwrap();
+    }
+
+    let completion_offset = {
+        let _it = stdx::timeit("change");
+        let mut text = host.analysis().file_text(file_id).unwrap().to_string();
+        let completion_offset =
+            patch(&mut text, "sel;\ndb.struct_data(self.id)", "self.;\ndb.struct_data(self.id)")
+                + "self.".len();
+        let mut change = Change::new();
+        change.change_file(file_id, Some(Arc::new(text)));
+        host.apply_change(change);
+        completion_offset
+    };
+
+    {
+        let _it = stdx::timeit("dot completion");
+        let _span = profile::cpu_span();
+        let analysis = host.analysis();
+        let config = CompletionConfig {
+            enable_postfix_completions: true,
+            enable_imports_on_the_fly: true,
+            add_call_parenthesis: true,
+            add_call_argument_snippets: true,
+            snippet_cap: SnippetCap::new(true),
+            insert_use: InsertUseConfig {
+                merge: Some(MergeBehavior::Full),
+                prefix_kind: hir::PrefixKind::ByCrate,
+                group: true,
+            },
+        };
+        let position =
+            FilePosition { file_id, offset: TextSize::try_from(completion_offset).unwrap() };
+        analysis.completions(&config, position).unwrap();
+    }
+}
+
+fn patch(what: &mut String, from: &str, to: &str) -> usize {
+    let idx = what.find(from).unwrap();
+    *what = what.replacen(from, to, 1);
+    idx
+}
diff --git a/crates/rust-analyzer/src/lib.rs b/crates/rust-analyzer/src/lib.rs
index d9a5030a0..da7e24bec 100644
--- a/crates/rust-analyzer/src/lib.rs
+++ b/crates/rust-analyzer/src/lib.rs
@@ -40,7 +40,7 @@ pub mod lsp_ext;
 pub mod config;
 
 #[cfg(test)]
-mod benchmarks;
+mod integrated_benchmarks;
 
 use serde::de::DeserializeOwned;
 use std::fmt;
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index a766aacad..ce7ece559 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -8,8 +8,7 @@ use std::{
 
 use always_assert::always;
 use crossbeam_channel::{select, Receiver};
-use ide::PrimeCachesProgress;
-use ide::{Canceled, FileId};
+use ide::{FileId, PrimeCachesProgress};
 use ide_db::base_db::VfsPath;
 use lsp_server::{Connection, Notification, Request, Response};
 use lsp_types::notification::Notification as _;
@@ -295,6 +294,8 @@ impl GlobalState {
                             state = Progress::End;
                             message = None;
                             fraction = 1.0;
+
+                            self.prime_caches_queue.op_completed(());
                         }
                     };
 
@@ -711,18 +712,23 @@ impl GlobalState {
     }
     fn update_file_notifications_on_threadpool(&mut self) {
         self.maybe_update_diagnostics();
+
+        // Ensure that only one cache priming task can run at a time
+        self.prime_caches_queue.request_op(());
+        if self.prime_caches_queue.should_start_op().is_none() {
+            return;
+        }
+
         self.task_pool.handle.spawn_with_sender({
             let snap = self.snapshot();
             move |sender| {
-                snap.analysis
-                    .prime_caches(|progress| {
-                        sender.send(Task::PrimeCaches(progress)).unwrap();
-                    })
-                    .unwrap_or_else(|_: Canceled| {
-                        // Pretend that we're done, so that the progress bar is removed. Otherwise
-                        // the editor may complain about it already existing.
-                        sender.send(Task::PrimeCaches(PrimeCachesProgress::Finished)).unwrap()
-                    });
+                let cb = |progress| {
+                    sender.send(Task::PrimeCaches(progress)).unwrap();
+                };
+                match snap.analysis.prime_caches(cb) {
+                    Ok(()) => (),
+                    Err(_canceled) => (),
+                }
             }
         });
     }
diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
index 5eff036ec..ecf6fd12f 100644
--- a/crates/rust-analyzer/src/to_proto.rs
+++ b/crates/rust-analyzer/src/to_proto.rs
@@ -898,7 +898,7 @@ pub(crate) fn code_action(
         (Some(it), _) => res.edit = Some(snippet_workspace_edit(snap, it)?),
         (None, Some((index, code_action_params))) => {
             res.data = Some(lsp_ext::CodeActionData {
-                id: format!("{}:{}", assist.id.0, index.to_string()),
+                id: format!("{}:{}:{}", assist.id.0, assist.id.1.name(), index),
                 code_action_params,
             });
         }
diff --git a/docs/dev/style.md b/docs/dev/style.md
index 6ab60b50e..00de7a711 100644
--- a/docs/dev/style.md
+++ b/docs/dev/style.md
@@ -449,6 +449,39 @@ fn query_all(name: String, case_sensitive: bool) -> Vec<Item> { ... }
 fn query_first(name: String, case_sensitive: bool) -> Option<Item> { ... }
 ```
 
+## Prefer Separate Functions Over Parameters
+
+If a function has a `bool` or an `Option` parameter, and it is always called with `true`, `false`, `Some` and `None` literals, split the function in two.
+
+```rust
+// GOOD
+fn caller_a() {
+    foo()
+}
+
+fn caller_b() {
+    foo_with_bar(Bar::new())
+}
+
+fn foo() { ... }
+fn foo_with_bar(bar: Bar) { ... }
+
+// BAD
+fn caller_a() {
+    foo(None)
+}
+
+fn caller_b() {
+    foo(Some(Bar::new()))
+}
+
+fn foo(bar: Option<Bar>) { ... }
+```
+
+**Rationale:** more often than not, such functions display "`false sharing`" -- they have additional `if` branching inside for two different cases.
+Splitting the two different control flows into two functions simplifies each path, and remove cross-dependencies between the two paths.
+If there's common code between `foo` and `foo_with_bar`, extract *that* into a common helper.
+
 ## Avoid Monomorphization
 
 Avoid making a lot of code type parametric, *especially* on the boundaries between crates.
diff --git a/docs/user/manual.adoc b/docs/user/manual.adoc
index 54195adb7..58722aaa3 100644
--- a/docs/user/manual.adoc
+++ b/docs/user/manual.adoc
@@ -611,6 +611,41 @@ For example, mutable bindings are underlined by default and you can override thi
 }
 ----
 
+Most themes doesn't support styling unsafe operations differently yet. You can fix this by adding overrides for the rules `operator.unsafe`, `function.unsafe`, and `method.unsafe`:
+
+[source,jsonc]
+----
+{
+   "editor.semanticTokenColorCustomizations": {
+         "rules": {
+             "operator.unsafe": "#ff6600",
+             "function.unsafe": "#ff6600"
+             "method.unsafe": "#ff6600"
+         }
+    },
+}
+----
+
+In addition to the top-level rules you can specify overrides for specific themes. For example, if you wanted to use a darker text color on a specific light theme, you might write:
+
+[source,jsonc]
+----
+{
+   "editor.semanticTokenColorCustomizations": {
+         "rules": {
+             "operator.unsafe": "#ff6600"
+         },
+         "[Ayu Light]": {
+            "rules": {
+               "operator.unsafe": "#572300"
+            }
+         }
+    },
+}
+----
+
+Make sure you include the brackets around the theme name. For example, use `"[Ayu Light]"` to customize the theme Ayu Light.
+
 ==== Special `when` clause context for keybindings.
 You may use `inRustProject` context to configure keybindings for rust projects only.
 For example:
diff --git a/xtask/src/dist.rs b/xtask/src/dist.rs
index 12a7fea1e..b6aa2f52a 100644
--- a/xtask/src/dist.rs
+++ b/xtask/src/dist.rs
@@ -66,6 +66,7 @@ fn dist_client(version: &str, release_tag: &str) -> Result<()> {
 
 fn dist_server(release_channel: &str) -> Result<()> {
     let _e = pushenv("RUST_ANALYZER_CHANNEL", release_channel);
+    let _e = pushenv("CARGO_PROFILE_RELEASE_LTO", "true");
     let target = get_target();
     if target.contains("-linux-gnu") || target.contains("-linux-musl") {
         env::set_var("CC", "clang");
diff --git a/xtask/src/flags.rs b/xtask/src/flags.rs
index f80a5dd16..69b3cb9c1 100644
--- a/xtask/src/flags.rs
+++ b/xtask/src/flags.rs
@@ -28,7 +28,6 @@ xflags::xflags! {
         }
 
         cmd fuzz-tests {}
-        cmd pre-cache {}
 
         cmd release {
             optional --dry-run
@@ -62,7 +61,6 @@ pub enum XtaskCmd {
     Help(Help),
     Install(Install),
     FuzzTests(FuzzTests),
-    PreCache(PreCache),
     Release(Release),
     Promote(Promote),
     Dist(Dist),
@@ -88,9 +86,6 @@ pub struct Install {
 pub struct FuzzTests;
 
 #[derive(Debug)]
-pub struct PreCache;
-
-#[derive(Debug)]
 pub struct Release {
     pub dry_run: bool,
 }
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
index ce3353410..d0bef7b7a 100644
--- a/xtask/src/main.rs
+++ b/xtask/src/main.rs
@@ -18,7 +18,6 @@ mod install;
 mod release;
 mod dist;
 mod metrics;
-mod pre_cache;
 
 use anyhow::{bail, Result};
 use std::{
@@ -39,7 +38,6 @@ fn main() -> Result<()> {
         }
         flags::XtaskCmd::Install(cmd) => cmd.run(),
         flags::XtaskCmd::FuzzTests(_) => run_fuzzer(),
-        flags::XtaskCmd::PreCache(cmd) => cmd.run(),
         flags::XtaskCmd::Release(cmd) => cmd.run(),
         flags::XtaskCmd::Promote(cmd) => cmd.run(),
         flags::XtaskCmd::Dist(cmd) => cmd.run(),
diff --git a/xtask/src/pre_cache.rs b/xtask/src/pre_cache.rs
deleted file mode 100644
index b456224fd..000000000
--- a/xtask/src/pre_cache.rs
+++ /dev/null
@@ -1,79 +0,0 @@
-use std::{
-    fs::FileType,
-    path::{Path, PathBuf},
-};
-
-use anyhow::Result;
-use xshell::rm_rf;
-
-use crate::flags;
-
-impl flags::PreCache {
-    /// Cleans the `./target` dir after the build such that only
-    /// dependencies are cached on CI.
-    pub(crate) fn run(self) -> Result<()> {
-        let slow_tests_cookie = Path::new("./target/.slow_tests_cookie");
-        if !slow_tests_cookie.exists() {
-            panic!("slow tests were skipped on CI!")
-        }
-        rm_rf(slow_tests_cookie)?;
-
-        for path in read_dir("./target/debug", FileType::is_file)? {
-            // Can't delete yourself on windows :-(
-            if !path.ends_with("xtask.exe") {
-                rm_rf(&path)?
-            }
-        }
-
-        rm_rf("./target/.rustc_info.json")?;
-
-        let to_delete = read_dir("./crates", FileType::is_dir)?
-            .into_iter()
-            .map(|path| path.file_name().unwrap().to_string_lossy().replace('-', "_"))
-            .collect::<Vec<_>>();
-
-        for &dir in ["./target/debug/deps", "target/debug/.fingerprint"].iter() {
-            for path in read_dir(dir, |_file_type| true)? {
-                if path.ends_with("xtask.exe") {
-                    continue;
-                }
-                let file_name = path.file_name().unwrap().to_string_lossy();
-                let (stem, _) = match rsplit_once(&file_name, '-') {
-                    Some(it) => it,
-                    None => {
-                        rm_rf(path)?;
-                        continue;
-                    }
-                };
-                let stem = stem.replace('-', "_");
-                if to_delete.contains(&stem) {
-                    rm_rf(path)?;
-                }
-            }
-        }
-
-        Ok(())
-    }
-}
-fn read_dir(path: impl AsRef<Path>, cond: impl Fn(&FileType) -> bool) -> Result<Vec<PathBuf>> {
-    read_dir_impl(path.as_ref(), &cond)
-}
-
-fn read_dir_impl(path: &Path, cond: &dyn Fn(&FileType) -> bool) -> Result<Vec<PathBuf>> {
-    let mut res = Vec::new();
-    for entry in path.read_dir()? {
-        let entry = entry?;
-        let file_type = entry.file_type()?;
-        if cond(&file_type) {
-            res.push(entry.path())
-        }
-    }
-    Ok(res)
-}
-
-fn rsplit_once(haystack: &str, delim: char) -> Option<(&str, &str)> {
-    let mut split = haystack.rsplitn(2, delim);
-    let suffix = split.next()?;
-    let prefix = split.next()?;
-    Some((prefix, suffix))
-}