89 files changed, 2858 insertions, 745 deletions

diff --git a/Cargo.lock b/Cargo.lock
index f6d5b900f..e667d45ec 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,9 +2,9 @@
 # It is not intended for manual editing.
 [[package]]
 name = "addr2line"
-version = "0.12.1"
+version = "0.12.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a49806b9dadc843c61e7c97e72490ad7f7220ae249012fbda9ad0609457c0543"
+checksum = "602d785912f476e480434627e8732e6766b760c045bbf897d9dfaa9f4fbd399c"
 dependencies = [
  "gimli",
 ]
@@ -288,9 +288,9 @@ checksum = "69b26e475fd29098530e709294e94e661974c851aed42512793f120fed4e199f"
 
 [[package]]
 name = "dtoa"
-version = "0.4.5"
+version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4358a9e11b9a09cf52383b451b49a169e8d797b68aa02301ff586d70d9661ea3"
+checksum = "134951f4028bdadb9b84baf4232681efbf277da25144b9b0ad65df75946c422b"
 
 [[package]]
 name = "either"
@@ -535,9 +535,9 @@ dependencies = [
 
 [[package]]
 name = "itoa"
-version = "0.4.5"
+version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b8b7a7c0c47db5545ed3fef7468ee7bb5b74691498139e4b3f6a20685dc6dd8e"
+checksum = "dc6f3ad7b9d11a0c00842ff8de1b60ee58661048eb8049ed33c73594f359d7e6"
 
 [[package]]
 name = "jemalloc-ctl"
@@ -640,9 +640,9 @@ dependencies = [
 
 [[package]]
 name = "lsp-server"
-version = "0.3.2"
+version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dccec31bfd027ac0dd288a78e19005fd89624d9099456e284b5241316a6c3072"
+checksum = "53b4ace8ebe5d2aff3687ce0ed507f6020d6a47a7de2b0d3d664ea237ffb0c62"
 dependencies = [
  "crossbeam-channel",
  "log",
@@ -830,9 +830,9 @@ dependencies = [
 
 [[package]]
 name = "paste"
-version = "0.1.17"
+version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "026c63fe245362be0322bfec5a9656d458d13f9cfb1785d1b38458b9968e8080"
+checksum = "45ca20c77d80be666aef2b45486da86238fabe33e38306bd3118fe4af33fa880"
 dependencies = [
  "paste-impl",
  "proc-macro-hack",
@@ -840,9 +840,9 @@ dependencies = [
 
 [[package]]
 name = "paste-impl"
-version = "0.1.17"
+version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7b9281a268ec213237dcd2aa3c3d0f46681b04ced37c1616fd36567a9e6954b0"
+checksum = "d95a7db200b97ef370c8e6de0088252f7e0dfff7d047a28528e47456c0fc98b6"
 dependencies = [
  "proc-macro-hack",
 ]
@@ -1519,18 +1519,18 @@ checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
 
 [[package]]
 name = "serde"
-version = "1.0.112"
+version = "1.0.113"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "736aac72d1eafe8e5962d1d1c3d99b0df526015ba40915cb3c49d042e92ec243"
+checksum = "6135c78461981c79497158ef777264c51d9d0f4f3fc3a4d22b915900e42dac6a"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.112"
+version = "1.0.113"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bf0343ce212ac0d3d6afd9391ac8e9c9efe06b533c8d33f660f6390cc4093f57"
+checksum = "93c5eaa17d0954cb481cdcfffe9d84fcfa7a1a9f2349271e678677be4c26ae31"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1550,9 +1550,9 @@ dependencies = [
 
 [[package]]
 name = "serde_repr"
-version = "0.1.5"
+version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cd02c7587ec314570041b2754829f84d873ced14a96d1fd1823531e11db40573"
+checksum = "2dc6b7951b17b051f3210b063f12cc17320e2fe30ae05b0fe2a3abb068551c76"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1604,9 +1604,9 @@ checksum = "ab16ced94dbd8a46c82fd81e3ed9a8727dac2977ea869d217bcc4ea1f122e81f"
 
 [[package]]
 name = "syn"
-version = "1.0.31"
+version = "1.0.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5304cfdf27365b7585c25d4af91b35016ed21ef88f17ced89c7093b43dba8b6"
+checksum = "a994520748611c17d163e81b6c4a4b13d11b7f63884362ab2efac3aa9cf16d00"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1702,6 +1702,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "tinyvec"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53953d2d3a5ad81d9f844a32f14ebb121f50b650cd59d0ee2a07cf13c617efed"
+
+[[package]]
 name = "unicode-bidi"
 version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1712,11 +1718,11 @@ dependencies = [
 
 [[package]]
 name = "unicode-normalization"
-version = "0.1.12"
+version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5479532badd04e128284890390c1e876ef7a993d0570b3597ae43dfa1d59afa4"
+checksum = "6fb19cf769fa8c6a80a162df694621ebeb4dafb606470b2b2fce0be40a98a977"
 dependencies = [
- "smallvec",
+ "tinyvec",
 ]
 
 [[package]]
diff --git a/crates/paths/src/lib.rs b/crates/paths/src/lib.rs
index c7ce0c42f..190c50913 100644
--- a/crates/paths/src/lib.rs
+++ b/crates/paths/src/lib.rs
@@ -2,7 +2,7 @@
 //! relative paths.
 use std::{
     convert::{TryFrom, TryInto},
-    ops,
+    io, ops,
     path::{Component, Path, PathBuf},
 };
 
@@ -46,6 +46,9 @@ impl TryFrom<&str> for AbsPathBuf {
 }
 
 impl AbsPathBuf {
+    pub fn canonicalized(path: &Path) -> io::Result<AbsPathBuf> {
+        path.canonicalize().map(|it| AbsPathBuf::try_from(it).unwrap())
+    }
     pub fn as_path(&self) -> &AbsPath {
         AbsPath::new_unchecked(self.0.as_path())
     }
diff --git a/crates/ra_db/src/input.rs b/crates/ra_db/src/input.rs
index bf26048f2..e6af99035 100644
--- a/crates/ra_db/src/input.rs
+++ b/crates/ra_db/src/input.rs
@@ -254,12 +254,12 @@ impl CrateGraph {
             return false;
         }
 
+        if target == from {
+            return true;
+        }
+
         for dep in &self[from].dependencies {
             let crate_id = dep.crate_id;
-            if crate_id == target {
-                return true;
-            }
-
             if self.dfs_find(target, crate_id, visited) {
                 return true;
             }
@@ -369,7 +369,7 @@ mod tests {
     use super::{CfgOptions, CrateGraph, CrateName, Dependency, Edition::Edition2018, Env, FileId};
 
     #[test]
-    fn it_should_panic_because_of_cycle_dependencies() {
+    fn detect_cyclic_dependency_indirect() {
         let mut graph = CrateGraph::default();
         let crate1 = graph.add_crate_root(
             FileId(1u32),
@@ -404,6 +404,31 @@ mod tests {
     }
 
     #[test]
+    fn detect_cyclic_dependency_direct() {
+        let mut graph = CrateGraph::default();
+        let crate1 = graph.add_crate_root(
+            FileId(1u32),
+            Edition2018,
+            None,
+            CfgOptions::default(),
+            Env::default(),
+            Default::default(),
+            Default::default(),
+        );
+        let crate2 = graph.add_crate_root(
+            FileId(2u32),
+            Edition2018,
+            None,
+            CfgOptions::default(),
+            Env::default(),
+            Default::default(),
+            Default::default(),
+        );
+        assert!(graph.add_dep(crate1, CrateName::new("crate2").unwrap(), crate2).is_ok());
+        assert!(graph.add_dep(crate2, CrateName::new("crate2").unwrap(), crate2).is_err());
+    }
+
+    #[test]
     fn it_works() {
         let mut graph = CrateGraph::default();
         let crate1 = graph.add_crate_root(
diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index 1a9f6cc76..ffd5278ec 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -26,8 +26,8 @@ use hir_ty::{
     autoderef,
     display::{HirDisplayError, HirFormatter},
     expr::ExprValidator,
-    method_resolution, ApplicationTy, Canonical, InEnvironment, Substs, TraitEnvironment, Ty,
-    TyDefId, TypeCtor,
+    method_resolution, ApplicationTy, Canonical, GenericPredicate, InEnvironment, Substs,
+    TraitEnvironment, Ty, TyDefId, TypeCtor,
 };
 use ra_db::{CrateId, CrateName, Edition, FileId};
 use ra_prof::profile;
@@ -186,6 +186,22 @@ impl ModuleDef {
 
         module.visibility_of(db, self)
     }
+
+    pub fn name(self, db: &dyn HirDatabase) -> Option<Name> {
+        match self {
+            ModuleDef::Adt(it) => Some(it.name(db)),
+            ModuleDef::Trait(it) => Some(it.name(db)),
+            ModuleDef::Function(it) => Some(it.name(db)),
+            ModuleDef::EnumVariant(it) => Some(it.name(db)),
+            ModuleDef::TypeAlias(it) => Some(it.name(db)),
+
+            ModuleDef::Module(it) => it.name(db),
+            ModuleDef::Const(it) => it.name(db),
+            ModuleDef::Static(it) => it.name(db),
+
+            ModuleDef::BuiltinType(it) => Some(it.as_name()),
+        }
+    }
 }
 
 pub use hir_def::{
@@ -1359,6 +1375,27 @@ impl Type {
         Some(adt.into())
     }
 
+    pub fn as_dyn_trait(&self) -> Option<Trait> {
+        self.ty.value.dyn_trait().map(Into::into)
+    }
+
+    pub fn as_impl_traits(&self, db: &dyn HirDatabase) -> Option<Vec<Trait>> {
+        self.ty.value.impl_trait_bounds(db).map(|it| {
+            it.into_iter()
+                .filter_map(|pred| match pred {
+                    hir_ty::GenericPredicate::Implemented(trait_ref) => {
+                        Some(Trait::from(trait_ref.trait_))
+                    }
+                    _ => None,
+                })
+                .collect()
+        })
+    }
+
+    pub fn as_associated_type_parent_trait(&self, db: &dyn HirDatabase) -> Option<Trait> {
+        self.ty.value.associated_type_parent_trait(db).map(Into::into)
+    }
+
     // FIXME: provide required accessors such that it becomes implementable from outside.
     pub fn is_equal_for_find_impls(&self, other: &Type) -> bool {
         match (&self.ty.value, &other.ty.value) {
@@ -1380,6 +1417,80 @@ impl Type {
             ty: InEnvironment { value: ty, environment: self.ty.environment.clone() },
         }
     }
+
+    pub fn walk(&self, db: &dyn HirDatabase, mut cb: impl FnMut(Type)) {
+        // TypeWalk::walk for a Ty at first visits parameters and only after that the Ty itself.
+        // We need a different order here.
+
+        fn walk_substs(
+            db: &dyn HirDatabase,
+            type_: &Type,
+            substs: &Substs,
+            cb: &mut impl FnMut(Type),
+        ) {
+            for ty in substs.iter() {
+                walk_type(db, &type_.derived(ty.clone()), cb);
+            }
+        }
+
+        fn walk_bounds(
+            db: &dyn HirDatabase,
+            type_: &Type,
+            bounds: &[GenericPredicate],
+            cb: &mut impl FnMut(Type),
+        ) {
+            for pred in bounds {
+                match pred {
+                    GenericPredicate::Implemented(trait_ref) => {
+                        cb(type_.clone());
+                        walk_substs(db, type_, &trait_ref.substs, cb);
+                    }
+                    _ => (),
+                }
+            }
+        }
+
+        fn walk_type(db: &dyn HirDatabase, type_: &Type, cb: &mut impl FnMut(Type)) {
+            let ty = type_.ty.value.strip_references();
+            match ty {
+                Ty::Apply(ApplicationTy { ctor, parameters }) => {
+                    match ctor {
+                        TypeCtor::Adt(_) => {
+                            cb(type_.derived(ty.clone()));
+                        }
+                        TypeCtor::AssociatedType(_) => {
+                            if let Some(_) = ty.associated_type_parent_trait(db) {
+                                cb(type_.derived(ty.clone()));
+                            }
+                        }
+                        _ => (),
+                    }
+
+                    // adt params, tuples, etc...
+                    walk_substs(db, type_, parameters, cb);
+                }
+                Ty::Opaque(opaque_ty) => {
+                    if let Some(bounds) = ty.impl_trait_bounds(db) {
+                        walk_bounds(db, &type_.derived(ty.clone()), &bounds, cb);
+                    }
+
+                    walk_substs(db, type_, &opaque_ty.parameters, cb);
+                }
+                Ty::Placeholder(_) => {
+                    if let Some(bounds) = ty.impl_trait_bounds(db) {
+                        walk_bounds(db, &type_.derived(ty.clone()), &bounds, cb);
+                    }
+                }
+                Ty::Dyn(bounds) => {
+                    walk_bounds(db, &type_.derived(ty.clone()), bounds.as_ref(), cb);
+                }
+
+                _ => (),
+            }
+        }
+
+        walk_type(db, self, &mut cb);
+    }
 }
 
 impl HirDisplay for Type {
diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
index b6b665de1..b25dac28e 100644
--- a/crates/ra_hir/src/db.rs
+++ b/crates/ra_hir/src/db.rs
@@ -16,7 +16,7 @@ pub use hir_expand::db::{
 pub use hir_ty::db::{
     AssociatedTyDataQuery, AssociatedTyValueQuery, CallableItemSignatureQuery, FieldTypesQuery,
     GenericDefaultsQuery, GenericPredicatesForParamQuery, GenericPredicatesQuery, HirDatabase,
-    HirDatabaseStorage, ImplDatumQuery, ImplSelfTyQuery, ImplTraitQuery, ImplsForTraitQuery,
+    HirDatabaseStorage, ImplDatumQuery, ImplSelfTyQuery, ImplTraitQuery, ImplsFromDepsQuery,
     ImplsInCrateQuery, InferQueryQuery, InternAssocTyValueQuery, InternChalkImplQuery,
     InternTypeCtorQuery, InternTypeParamIdQuery, ReturnTypeImplTraitsQuery, StructDatumQuery,
     TraitDatumQuery, TraitSolveQuery, TyQuery, ValueTyQuery,
diff --git a/crates/ra_hir/src/semantics.rs b/crates/ra_hir/src/semantics.rs
index a232a5856..6a49c424a 100644
--- a/crates/ra_hir/src/semantics.rs
+++ b/crates/ra_hir/src/semantics.rs
@@ -6,9 +6,9 @@ use std::{cell::RefCell, fmt, iter::successors};
 
 use hir_def::{
     resolver::{self, HasResolver, Resolver},
-    AsMacroCall, TraitId,
+    AsMacroCall, TraitId, VariantId,
 };
-use hir_expand::{hygiene::Hygiene, ExpansionInfo};
+use hir_expand::{diagnostics::AstDiagnostic, hygiene::Hygiene, ExpansionInfo};
 use hir_ty::associated_type_shorthand_candidates;
 use itertools::Itertools;
 use ra_db::{FileId, FileRange};
@@ -104,6 +104,13 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         tree
     }
 
+    pub fn ast<T: AstDiagnostic + Diagnostic>(&self, d: &T) -> <T as AstDiagnostic>::AST {
+        let file_id = d.source().file_id;
+        let root = self.db.parse_or_expand(file_id).unwrap();
+        self.cache(root, file_id);
+        d.ast(self.db)
+    }
+
     pub fn expand(&self, macro_call: &ast::MacroCall) -> Option<SyntaxNode> {
         let macro_call = self.find_file(macro_call.syntax().clone()).with_value(macro_call);
         let sa = self.analyze2(macro_call.map(|it| it.syntax()), None);
@@ -247,6 +254,10 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.analyze(path.syntax()).resolve_path(self.db, path)
     }
 
+    pub fn resolve_variant(&self, record_lit: ast::RecordLit) -> Option<VariantId> {
+        self.analyze(record_lit.syntax()).resolve_variant(self.db, record_lit)
+    }
+
     pub fn lower_path(&self, path: &ast::Path) -> Option<Path> {
         let src = self.find_file(path.syntax().clone());
         Path::from_src(path.clone(), &Hygiene::new(self.db.upcast(), src.file_id.into()))
diff --git a/crates/ra_hir/src/source_analyzer.rs b/crates/ra_hir/src/source_analyzer.rs
index 7c6bbea13..757d1e397 100644
--- a/crates/ra_hir/src/source_analyzer.rs
+++ b/crates/ra_hir/src/source_analyzer.rs
@@ -313,6 +313,16 @@ impl SourceAnalyzer {
         })?;
         Some(macro_call_id.as_file())
     }
+
+    pub(crate) fn resolve_variant(
+        &self,
+        db: &dyn HirDatabase,
+        record_lit: ast::RecordLit,
+    ) -> Option<VariantId> {
+        let infer = self.infer.as_ref()?;
+        let expr_id = self.expr_id(db, &record_lit.into())?;
+        infer.variant_resolution_for_expr(expr_id)
+    }
 }
 
 fn scope_for(
diff --git a/crates/ra_hir_def/src/body/scope.rs b/crates/ra_hir_def/src/body/scope.rs
index e48ff38f9..661f00407 100644
--- a/crates/ra_hir_def/src/body/scope.rs
+++ b/crates/ra_hir_def/src/body/scope.rs
@@ -87,15 +87,13 @@ impl ExprScopes {
     }
 
     fn add_bindings(&mut self, body: &Body, scope: ScopeId, pat: PatId) {
-        match &body[pat] {
-            Pat::Bind { name, .. } => {
-                // bind can have a sub pattern, but it's actually not allowed
-                // to bind to things in there
-                let entry = ScopeEntry { name: name.clone(), pat };
-                self.scopes[scope].entries.push(entry)
-            }
-            p => p.walk_child_pats(|pat| self.add_bindings(body, scope, pat)),
+        let pattern = &body[pat];
+        if let Pat::Bind { name, .. } = pattern {
+            let entry = ScopeEntry { name: name.clone(), pat };
+            self.scopes[scope].entries.push(entry);
         }
+
+        pattern.walk_child_pats(|pat| self.add_bindings(body, scope, pat));
     }
 
     fn add_params_bindings(&mut self, body: &Body, scope: ScopeId, params: &[PatId]) {
@@ -190,8 +188,8 @@ mod tests {
         }
     }
 
-    fn do_check(code: &str, expected: &[&str]) {
-        let (off, code) = extract_offset(code);
+    fn do_check(ra_fixture: &str, expected: &[&str]) {
+        let (off, code) = extract_offset(ra_fixture);
         let code = {
             let mut buf = String::new();
             let off: usize = off.into();
@@ -300,6 +298,22 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_bindings_after_at() {
+        do_check(
+            r"
+            fn foo() {
+                match Some(()) {
+                    opt @ Some(unit) => {
+                        <|>
+                    }
+                    _ => {}
+                }
+            }",
+            &["opt", "unit"],
+        );
+    }
+
     fn do_check_local_name(code: &str, expected_offset: u32) {
         let (off, code) = extract_offset(code);
 
diff --git a/crates/ra_hir_def/src/lib.rs b/crates/ra_hir_def/src/lib.rs
index edc59e5a8..af2a717c9 100644
--- a/crates/ra_hir_def/src/lib.rs
+++ b/crates/ra_hir_def/src/lib.rs
@@ -159,7 +159,7 @@ pub struct TypeAliasId(salsa::InternId);
 type TypeAliasLoc = AssocItemLoc<ast::TypeAliasDef>;
 impl_intern!(TypeAliasId, TypeAliasLoc, intern_type_alias, lookup_intern_type_alias);
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Ord, PartialOrd)]
 pub struct ImplId(salsa::InternId);
 type ImplLoc = ItemLoc<ast::ImplDef>;
 impl_intern!(ImplId, ImplLoc, intern_impl, lookup_intern_impl);
diff --git a/crates/ra_hir_def/src/nameres.rs b/crates/ra_hir_def/src/nameres.rs
index b3e5f491a..b8560fdc9 100644
--- a/crates/ra_hir_def/src/nameres.rs
+++ b/crates/ra_hir_def/src/nameres.rs
@@ -119,13 +119,6 @@ impl Default for ModuleOrigin {
 }
 
 impl ModuleOrigin {
-    pub(crate) fn not_sure_file(file: Option<FileId>, declaration: AstId<ast::Module>) -> Self {
-        match file {
-            None => ModuleOrigin::Inline { definition: declaration },
-            Some(definition) => ModuleOrigin::File { declaration, definition },
-        }
-    }
-
     fn declaration(&self) -> Option<AstId<ast::Module>> {
         match self {
             ModuleOrigin::File { declaration: module, .. }
diff --git a/crates/ra_hir_def/src/nameres/collector.rs b/crates/ra_hir_def/src/nameres/collector.rs
index 976e5e585..b8f6aac8f 100644
--- a/crates/ra_hir_def/src/nameres/collector.rs
+++ b/crates/ra_hir_def/src/nameres/collector.rs
@@ -36,8 +36,8 @@ pub(super) fn collect_defs(db: &dyn DefDatabase, mut def_map: CrateDefMap) -> Cr
 
     // populate external prelude
     for dep in &crate_graph[def_map.krate].dependencies {
-        let dep_def_map = db.crate_def_map(dep.crate_id);
         log::debug!("crate dep {:?} -> {:?}", dep.name, dep.crate_id);
+        let dep_def_map = db.crate_def_map(dep.crate_id);
         def_map.extern_prelude.insert(
             dep.as_name(),
             ModuleId { krate: dep.crate_id, local_id: dep_def_map.root }.into(),
@@ -825,7 +825,10 @@ impl ModCollector<'_, '_> {
         let modules = &mut self.def_collector.def_map.modules;
         let res = modules.alloc(ModuleData::default());
         modules[res].parent = Some(self.module_id);
-        modules[res].origin = ModuleOrigin::not_sure_file(definition, declaration);
+        modules[res].origin = match definition {
+            None => ModuleOrigin::Inline { definition: declaration },
+            Some(definition) => ModuleOrigin::File { declaration, definition },
+        };
         for (name, mac) in modules[self.module_id].scope.collect_legacy_macros() {
             modules[res].scope.define_legacy_macro(name, mac)
         }
diff --git a/crates/ra_hir_ty/src/_match.rs b/crates/ra_hir_ty/src/_match.rs
index 02a7a61f1..5495ce284 100644
--- a/crates/ra_hir_ty/src/_match.rs
+++ b/crates/ra_hir_ty/src/_match.rs
@@ -312,20 +312,16 @@ impl PatStack {
         Self(v)
     }
 
-    fn is_empty(&self) -> bool {
-        self.0.is_empty()
-    }
-
-    fn head(&self) -> PatIdOrWild {
-        self.0[0]
-    }
-
     fn get_head(&self) -> Option<PatIdOrWild> {
         self.0.first().copied()
     }
 
+    fn tail(&self) -> &[PatIdOrWild] {
+        self.0.get(1..).unwrap_or(&[])
+    }
+
     fn to_tail(&self) -> PatStack {
-        Self::from_slice(&self.0[1..])
+        Self::from_slice(self.tail())
     }
 
     fn replace_head_with<I, T>(&self, pats: I) -> PatStack
@@ -347,7 +343,7 @@ impl PatStack {
     ///
     /// See the module docs and the associated documentation in rustc for details.
     fn specialize_wildcard(&self, cx: &MatchCheckCtx) -> Option<PatStack> {
-        if matches!(self.head().as_pat(cx), Pat::Wild) {
+        if matches!(self.get_head()?.as_pat(cx), Pat::Wild) {
             Some(self.to_tail())
         } else {
             None
@@ -362,11 +358,12 @@ impl PatStack {
         cx: &MatchCheckCtx,
         constructor: &Constructor,
     ) -> MatchCheckResult<Option<PatStack>> {
-        if self.is_empty() {
-            return Ok(None);
-        }
+        let head = match self.get_head() {
+            Some(head) => head,
+            None => return Ok(None),
+        };
 
-        let head_pat = self.head().as_pat(cx);
+        let head_pat = head.as_pat(cx);
         let result = match (head_pat, constructor) {
             (Pat::Tuple { args: ref pat_ids, ellipsis }, Constructor::Tuple { arity: _ }) => {
                 if ellipsis.is_some() {
@@ -394,7 +391,7 @@ impl PatStack {
             (Pat::Wild, constructor) => Some(self.expand_wildcard(cx, constructor)?),
             (Pat::Path(_), Constructor::Enum(constructor)) => {
                 // unit enum variants become `Pat::Path`
-                let pat_id = self.head().as_id().expect("we know this isn't a wild");
+                let pat_id = head.as_id().expect("we know this isn't a wild");
                 if !enum_variant_matches(cx, pat_id, *constructor) {
                     None
                 } else {
@@ -405,7 +402,7 @@ impl PatStack {
                 Pat::TupleStruct { args: ref pat_ids, ellipsis, .. },
                 Constructor::Enum(enum_constructor),
             ) => {
-                let pat_id = self.head().as_id().expect("we know this isn't a wild");
+                let pat_id = head.as_id().expect("we know this isn't a wild");
                 if !enum_variant_matches(cx, pat_id, *enum_constructor) {
                     None
                 } else {
@@ -445,7 +442,7 @@ impl PatStack {
                 }
             }
             (Pat::Record { args: ref arg_patterns, .. }, Constructor::Enum(e)) => {
-                let pat_id = self.head().as_id().expect("we know this isn't a wild");
+                let pat_id = head.as_id().expect("we know this isn't a wild");
                 if !enum_variant_matches(cx, pat_id, *e) {
                     None
                 } else {
@@ -491,7 +488,7 @@ impl PatStack {
     ) -> MatchCheckResult<PatStack> {
         assert_eq!(
             Pat::Wild,
-            self.head().as_pat(cx),
+            self.get_head().expect("expand_wildcard called on empty PatStack").as_pat(cx),
             "expand_wildcard must only be called on PatStack with wild at head",
         );
 
@@ -509,7 +506,6 @@ impl PatStack {
     }
 }
 
-#[derive(Debug)]
 /// A collection of PatStack.
 ///
 /// This type is modeled from the struct of the same name in `rustc`.
@@ -623,13 +619,16 @@ pub(crate) fn is_useful(
         _ => (),
     }
 
-    if v.is_empty() {
-        let result = if matrix.is_empty() { Usefulness::Useful } else { Usefulness::NotUseful };
+    let head = match v.get_head() {
+        Some(head) => head,
+        None => {
+            let result = if matrix.is_empty() { Usefulness::Useful } else { Usefulness::NotUseful };
 
-        return Ok(result);
-    }
+            return Ok(result);
+        }
+    };
 
-    if let Pat::Or(pat_ids) = v.head().as_pat(cx) {
+    if let Pat::Or(pat_ids) = head.as_pat(cx) {
         let mut found_unimplemented = false;
         let any_useful = pat_ids.iter().any(|&pat_id| {
             let v = PatStack::from_pattern(pat_id);
@@ -653,7 +652,7 @@ pub(crate) fn is_useful(
         };
     }
 
-    if let Some(constructor) = pat_constructor(cx, v.head())? {
+    if let Some(constructor) = pat_constructor(cx, head)? {
         let matrix = matrix.specialize_constructor(&cx, &constructor)?;
         let v = v
             .specialize_constructor(&cx, &constructor)?
@@ -854,10 +853,10 @@ mod tests {
     }
 
     pub(super) fn check_no_diagnostic(ra_fixture: &str) {
-        let diagnostic_count =
-            TestDB::with_single_file(ra_fixture).0.diagnostic::<MissingMatchArms>().1;
+        let (s, diagnostic_count) =
+            TestDB::with_single_file(ra_fixture).0.diagnostic::<MissingMatchArms>();
 
-        assert_eq!(0, diagnostic_count, "expected no diagnostic, found one");
+        assert_eq!(0, diagnostic_count, "expected no diagnostic, found one: {}", s);
     }
 
     #[test]
@@ -2014,6 +2013,28 @@ mod tests {
         ",
         );
     }
+
+    #[test]
+    fn or_pattern_panic_2() {
+        // FIXME: This is a false positive, but the code used to cause a panic in the match checker,
+        // so this acts as a regression test for that.
+        check_diagnostic(
+            r"
+            pub enum Category {
+                Infinity,
+                Zero,
+            }
+
+            fn panic(a: Category, b: Category) {
+                match (a, b) {
+                    (Category::Infinity, Category::Infinity) | (Category::Zero, Category::Zero) => {}
+
+                    (Category::Infinity | Category::Zero, _) => {}
+                }
+            }
+        ",
+        );
+    }
 }
 
 #[cfg(test)]
diff --git a/crates/ra_hir_ty/src/db.rs b/crates/ra_hir_ty/src/db.rs
index bf71d38d6..7889b8d2c 100644
--- a/crates/ra_hir_ty/src/db.rs
+++ b/crates/ra_hir_ty/src/db.rs
@@ -3,15 +3,15 @@
 use std::sync::Arc;
 
 use hir_def::{
-    db::DefDatabase, DefWithBodyId, FunctionId, GenericDefId, ImplId, LocalFieldId, TraitId,
-    TypeParamId, VariantId,
+    db::DefDatabase, DefWithBodyId, FunctionId, GenericDefId, ImplId, LocalFieldId, TypeParamId,
+    VariantId,
 };
 use ra_arena::map::ArenaMap;
 use ra_db::{impl_intern_key, salsa, CrateId, Upcast};
 use ra_prof::profile;
 
 use crate::{
-    method_resolution::{CrateImplDefs, TyFingerprint},
+    method_resolution::CrateImplDefs,
     traits::{chalk, AssocTyValue, Impl},
     Binders, CallableDef, GenericPredicate, InferenceResult, OpaqueTyId, PolyFnSig,
     ReturnTypeImplTraits, Substs, TraitRef, Ty, TyDefId, TypeCtor, ValueTyDefId,
@@ -70,13 +70,8 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     #[salsa::invoke(crate::method_resolution::CrateImplDefs::impls_in_crate_query)]
     fn impls_in_crate(&self, krate: CrateId) -> Arc<CrateImplDefs>;
 
-    #[salsa::invoke(crate::traits::impls_for_trait_query)]
-    fn impls_for_trait(
-        &self,
-        krate: CrateId,
-        trait_: TraitId,
-        self_ty_fp: Option<TyFingerprint>,
-    ) -> Arc<[ImplId]>;
+    #[salsa::invoke(crate::method_resolution::CrateImplDefs::impls_from_deps_query)]
+    fn impls_from_deps(&self, krate: CrateId) -> Arc<CrateImplDefs>;
 
     // Interned IDs for Chalk integration
     #[salsa::interned]
diff --git a/crates/ra_hir_ty/src/diagnostics.rs b/crates/ra_hir_ty/src/diagnostics.rs
index 2c7298714..ebd9cb08f 100644
--- a/crates/ra_hir_ty/src/diagnostics.rs
+++ b/crates/ra_hir_ty/src/diagnostics.rs
@@ -6,7 +6,7 @@ use hir_expand::{db::AstDatabase, name::Name, HirFileId, InFile};
 use ra_syntax::{ast, AstNode, AstPtr, SyntaxNodePtr};
 use stdx::format_to;
 
-pub use hir_def::{diagnostics::UnresolvedModule, expr::MatchArm};
+pub use hir_def::{diagnostics::UnresolvedModule, expr::MatchArm, path::Path};
 pub use hir_expand::diagnostics::{AstDiagnostic, Diagnostic, DiagnosticSink};
 
 #[derive(Debug)]
@@ -29,6 +29,16 @@ impl Diagnostic for NoSuchField {
     }
 }
 
+impl AstDiagnostic for NoSuchField {
+    type AST = ast::RecordField;
+
+    fn ast(&self, db: &impl AstDatabase) -> Self::AST {
+        let root = db.parse_or_expand(self.source().file_id).unwrap();
+        let node = self.source().value.to_node(&root);
+        ast::RecordField::cast(node).unwrap()
+    }
+}
+
 #[derive(Debug)]
 pub struct MissingFields {
     pub file: HirFileId,
diff --git a/crates/ra_hir_ty/src/infer/expr.rs b/crates/ra_hir_ty/src/infer/expr.rs
index 9fd310f69..a9565a58d 100644
--- a/crates/ra_hir_ty/src/infer/expr.rs
+++ b/crates/ra_hir_ty/src/infer/expr.rs
@@ -10,12 +10,12 @@ use hir_def::{
     resolver::resolver_for_expr,
     AdtId, AssocContainerId, FieldId, Lookup,
 };
-use hir_expand::name::Name;
+use hir_expand::name::{name, Name};
 use ra_syntax::ast::RangeOp;
 
 use crate::{
     autoderef, method_resolution, op,
-    traits::InEnvironment,
+    traits::{FnTrait, InEnvironment},
     utils::{generics, variant_data, Generics},
     ApplicationTy, Binders, CallableDef, InferTy, IntTy, Mutability, Obligation, Rawness, Substs,
     TraitRef, Ty, TypeCtor,
@@ -63,6 +63,58 @@ impl<'a> InferenceContext<'a> {
         self.resolve_ty_as_possible(ty)
     }
 
+    fn callable_sig_from_fn_trait(&mut self, ty: &Ty, num_args: usize) -> Option<(Vec<Ty>, Ty)> {
+        let krate = self.resolver.krate()?;
+        let fn_once_trait = FnTrait::FnOnce.get_id(self.db, krate)?;
+        let output_assoc_type =
+            self.db.trait_data(fn_once_trait).associated_type_by_name(&name![Output])?;
+        let generic_params = generics(self.db.upcast(), fn_once_trait.into());
+        if generic_params.len() != 2 {
+            return None;
+        }
+
+        let mut param_builder = Substs::builder(num_args);
+        let mut arg_tys = vec![];
+        for _ in 0..num_args {
+            let arg = self.table.new_type_var();
+            param_builder = param_builder.push(arg.clone());
+            arg_tys.push(arg);
+        }
+        let parameters = param_builder.build();
+        let arg_ty = Ty::Apply(ApplicationTy {
+            ctor: TypeCtor::Tuple { cardinality: num_args as u16 },
+            parameters,
+        });
+        let substs = Substs::build_for_generics(&generic_params)
+            .push(ty.clone())
+            .push(arg_ty.clone())
+            .build();
+
+        let trait_env = Arc::clone(&self.trait_env);
+        let implements_fn_trait =
+            Obligation::Trait(TraitRef { trait_: fn_once_trait, substs: substs.clone() });
+        let goal = self.canonicalizer().canonicalize_obligation(InEnvironment {
+            value: implements_fn_trait.clone(),
+            environment: trait_env,
+        });
+        if self.db.trait_solve(krate, goal.value).is_some() {
+            self.obligations.push(implements_fn_trait);
+            let output_proj_ty =
+                crate::ProjectionTy { associated_ty: output_assoc_type, parameters: substs };
+            let return_ty = self.normalize_projection_ty(output_proj_ty);
+            Some((arg_tys, return_ty))
+        } else {
+            None
+        }
+    }
+
+    pub fn callable_sig(&mut self, ty: &Ty, num_args: usize) -> Option<(Vec<Ty>, Ty)> {
+        match ty.callable_sig(self.db) {
+            Some(sig) => Some((sig.params().to_vec(), sig.ret().clone())),
+            None => self.callable_sig_from_fn_trait(ty, num_args),
+        }
+    }
+
     fn infer_expr_inner(&mut self, tgt_expr: ExprId, expected: &Expectation) -> Ty {
         let body = Arc::clone(&self.body); // avoid borrow checker problem
         let ty = match &body[tgt_expr] {
@@ -198,14 +250,23 @@ impl<'a> InferenceContext<'a> {
             }
             Expr::Call { callee, args } => {
                 let callee_ty = self.infer_expr(*callee, &Expectation::none());
-                let (param_tys, ret_ty) = match callee_ty.callable_sig(self.db) {
-                    Some(sig) => (sig.params().to_vec(), sig.ret().clone()),
-                    None => {
-                        // Not callable
-                        // FIXME: report an error
-                        (Vec::new(), Ty::Unknown)
-                    }
-                };
+                let canonicalized = self.canonicalizer().canonicalize_ty(callee_ty.clone());
+                let mut derefs = autoderef(
+                    self.db,
+                    self.resolver.krate(),
+                    InEnvironment {
+                        value: canonicalized.value.clone(),
+                        environment: self.trait_env.clone(),
+                    },
+                );
+                let (param_tys, ret_ty): (Vec<Ty>, Ty) = derefs
+                    .find_map(|callee_deref_ty| {
+                        self.callable_sig(
+                            &canonicalized.decanonicalize_ty(callee_deref_ty.value),
+                            args.len(),
+                        )
+                    })
+                    .unwrap_or((Vec::new(), Ty::Unknown));
                 self.register_obligations_for_call(&callee_ty);
                 self.check_call_arguments(args, &param_tys);
                 self.normalize_associated_types_in(ret_ty)
diff --git a/crates/ra_hir_ty/src/infer/path.rs b/crates/ra_hir_ty/src/infer/path.rs
index 1ad0d8397..80d7ed10e 100644
--- a/crates/ra_hir_ty/src/infer/path.rs
+++ b/crates/ra_hir_ty/src/infer/path.rs
@@ -81,7 +81,7 @@ impl<'a> InferenceContext<'a> {
                 let generics = crate::utils::generics(self.db.upcast(), impl_id.into());
                 let substs = Substs::type_params_for_generics(&generics);
                 let ty = self.db.impl_self_ty(impl_id).subst(&substs);
-                if let Some((AdtId::StructId(struct_id), _)) = ty.as_adt() {
+                if let Some((AdtId::StructId(struct_id), substs)) = ty.as_adt() {
                     let ty = self.db.value_ty(struct_id.into()).subst(&substs);
                     return Some(ty);
                 } else {
diff --git a/crates/ra_hir_ty/src/lib.rs b/crates/ra_hir_ty/src/lib.rs
index 2b9372b4b..f22232324 100644
--- a/crates/ra_hir_ty/src/lib.rs
+++ b/crates/ra_hir_ty/src/lib.rs
@@ -73,6 +73,7 @@ pub use lower::{
 pub use traits::{InEnvironment, Obligation, ProjectionPredicate, TraitEnvironment};
 
 pub use chalk_ir::{BoundVar, DebruijnIndex};
+use itertools::Itertools;
 
 /// A type constructor or type name: this might be something like the primitive
 /// type `bool`, a struct like `Vec`, or things like function pointers or
@@ -815,6 +816,11 @@ impl Ty {
         }
     }
 
+    /// If this is a `dyn Trait`, returns that trait.
+    pub fn dyn_trait(&self) -> Option<TraitId> {
+        self.dyn_trait_ref().map(|it| it.trait_)
+    }
+
     fn builtin_deref(&self) -> Option<Ty> {
         match self {
             Ty::Apply(a_ty) => match a_ty.ctor {
@@ -867,13 +873,56 @@ impl Ty {
         }
     }
 
-    /// If this is a `dyn Trait`, returns that trait.
-    pub fn dyn_trait(&self) -> Option<TraitId> {
+    pub fn impl_trait_bounds(&self, db: &dyn HirDatabase) -> Option<Vec<GenericPredicate>> {
         match self {
-            Ty::Dyn(predicates) => predicates.iter().find_map(|pred| match pred {
-                GenericPredicate::Implemented(tr) => Some(tr.trait_),
-                _ => None,
-            }),
+            Ty::Opaque(opaque_ty) => {
+                let predicates = match opaque_ty.opaque_ty_id {
+                    OpaqueTyId::ReturnTypeImplTrait(func, idx) => {
+                        db.return_type_impl_traits(func).map(|it| {
+                            let data = (*it)
+                                .as_ref()
+                                .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
+                            data.clone().subst(&opaque_ty.parameters)
+                        })
+                    }
+                };
+
+                predicates.map(|it| it.value)
+            }
+            Ty::Placeholder(id) => {
+                let generic_params = db.generic_params(id.parent);
+                let param_data = &generic_params.types[id.local_id];
+                match param_data.provenance {
+                    hir_def::generics::TypeParamProvenance::ArgumentImplTrait => {
+                        let predicates = db
+                            .generic_predicates_for_param(*id)
+                            .into_iter()
+                            .map(|pred| pred.value.clone())
+                            .collect_vec();
+
+                        Some(predicates)
+                    }
+                    _ => None,
+                }
+            }
+            _ => None,
+        }
+    }
+
+    pub fn associated_type_parent_trait(&self, db: &dyn HirDatabase) -> Option<TraitId> {
+        match self {
+            Ty::Apply(ApplicationTy { ctor: TypeCtor::AssociatedType(type_alias_id), .. }) => {
+                match type_alias_id.lookup(db.upcast()).container {
+                    AssocContainerId::TraitId(trait_id) => Some(trait_id),
+                    _ => None,
+                }
+            }
+            Ty::Projection(projection_ty) => {
+                match projection_ty.associated_ty.lookup(db.upcast()).container {
+                    AssocContainerId::TraitId(trait_id) => Some(trait_id),
+                    _ => None,
+                }
+            }
             _ => None,
         }
     }
@@ -1057,5 +1106,5 @@ pub struct ReturnTypeImplTraits {
 
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub(crate) struct ReturnTypeImplTrait {
-    pub(crate) bounds: Binders<Vec<GenericPredicate>>,
+    pub bounds: Binders<Vec<GenericPredicate>>,
 }
diff --git a/crates/ra_hir_ty/src/lower.rs b/crates/ra_hir_ty/src/lower.rs
index 42713928f..d5154f436 100644
--- a/crates/ra_hir_ty/src/lower.rs
+++ b/crates/ra_hir_ty/src/lower.rs
@@ -337,17 +337,17 @@ impl Ty {
                     TraitRef::from_resolved_path(ctx, trait_, resolved_segment, self_ty);
                 let ty = if remaining_segments.len() == 1 {
                     let segment = remaining_segments.first().unwrap();
-                    let associated_ty = associated_type_by_name_including_super_traits(
-                        ctx.db.upcast(),
-                        trait_ref.trait_,
+                    let found = associated_type_by_name_including_super_traits(
+                        ctx.db,
+                        trait_ref.clone(),
                         &segment.name,
                     );
-                    match associated_ty {
-                        Some(associated_ty) => {
+                    match found {
+                        Some((super_trait_ref, associated_ty)) => {
                             // FIXME handle type parameters on the segment
                             Ty::Projection(ProjectionTy {
                                 associated_ty,
-                                parameters: trait_ref.substs,
+                                parameters: super_trait_ref.substs,
                             })
                         }
                         None => {
@@ -467,6 +467,9 @@ impl Ty {
                             }
                             TypeParamLoweringMode::Variable => t.substs.clone(),
                         };
+                        // We need to shift in the bound vars, since
+                        // associated_type_shorthand_candidates does not do that
+                        let substs = substs.shift_bound_vars(ctx.in_binders);
                         // FIXME handle type parameters on the segment
                         return Some(Ty::Projection(ProjectionTy {
                             associated_ty,
@@ -706,17 +709,17 @@ fn assoc_type_bindings_from_type_bound<'a>(
         .flat_map(|segment| segment.args_and_bindings.into_iter())
         .flat_map(|args_and_bindings| args_and_bindings.bindings.iter())
         .flat_map(move |binding| {
-            let associated_ty = associated_type_by_name_including_super_traits(
-                ctx.db.upcast(),
-                trait_ref.trait_,
+            let found = associated_type_by_name_including_super_traits(
+                ctx.db,
+                trait_ref.clone(),
                 &binding.name,
             );
-            let associated_ty = match associated_ty {
+            let (super_trait_ref, associated_ty) = match found {
                 None => return SmallVec::<[GenericPredicate; 1]>::new(),
                 Some(t) => t,
             };
             let projection_ty =
-                ProjectionTy { associated_ty, parameters: trait_ref.substs.clone() };
+                ProjectionTy { associated_ty, parameters: super_trait_ref.substs.clone() };
             let mut preds = SmallVec::with_capacity(
                 binding.type_ref.as_ref().map_or(0, |_| 1) + binding.bounds.len(),
             );
diff --git a/crates/ra_hir_ty/src/method_resolution.rs b/crates/ra_hir_ty/src/method_resolution.rs
index e83b39456..ed638c195 100644
--- a/crates/ra_hir_ty/src/method_resolution.rs
+++ b/crates/ra_hir_ty/src/method_resolution.rs
@@ -38,18 +38,53 @@ impl TyFingerprint {
     }
 }
 
+/// A queryable and mergeable collection of impls.
 #[derive(Debug, PartialEq, Eq)]
 pub struct CrateImplDefs {
-    impls: FxHashMap<TyFingerprint, Vec<ImplId>>,
+    inherent_impls: FxHashMap<TyFingerprint, Vec<ImplId>>,
     impls_by_trait: FxHashMap<TraitId, FxHashMap<Option<TyFingerprint>, Vec<ImplId>>>,
 }
 
 impl CrateImplDefs {
     pub(crate) fn impls_in_crate_query(db: &dyn HirDatabase, krate: CrateId) -> Arc<CrateImplDefs> {
         let _p = profile("impls_in_crate_query");
-        let mut res =
-            CrateImplDefs { impls: FxHashMap::default(), impls_by_trait: FxHashMap::default() };
+        let mut res = CrateImplDefs {
+            inherent_impls: FxHashMap::default(),
+            impls_by_trait: FxHashMap::default(),
+        };
+        res.fill(db, krate);
+
+        Arc::new(res)
+    }
+
+    /// Collects all impls from transitive dependencies of `krate` that may be used by `krate`.
+    ///
+    /// The full set of impls that can be used by `krate` is the returned map plus all the impls
+    /// from `krate` itself.
+    pub(crate) fn impls_from_deps_query(
+        db: &dyn HirDatabase,
+        krate: CrateId,
+    ) -> Arc<CrateImplDefs> {
+        let _p = profile("impls_from_deps_query");
+        let crate_graph = db.crate_graph();
+        let mut res = CrateImplDefs {
+            inherent_impls: FxHashMap::default(),
+            impls_by_trait: FxHashMap::default(),
+        };
 
+        // For each dependency, calculate `impls_from_deps` recursively, then add its own
+        // `impls_in_crate`.
+        // As we might visit crates multiple times, `merge` has to deduplicate impls to avoid
+        // wasting memory.
+        for dep in &crate_graph[krate].dependencies {
+            res.merge(&db.impls_from_deps(dep.crate_id));
+            res.merge(&db.impls_in_crate(dep.crate_id));
+        }
+
+        Arc::new(res)
+    }
+
+    fn fill(&mut self, db: &dyn HirDatabase, krate: CrateId) {
         let crate_def_map = db.crate_def_map(krate);
         for (_module_id, module_data) in crate_def_map.modules.iter() {
             for impl_id in module_data.scope.impls() {
@@ -57,7 +92,7 @@ impl CrateImplDefs {
                     Some(tr) => {
                         let self_ty = db.impl_self_ty(impl_id);
                         let self_ty_fp = TyFingerprint::for_impl(&self_ty.value);
-                        res.impls_by_trait
+                        self.impls_by_trait
                             .entry(tr.value.trait_)
                             .or_default()
                             .entry(self_ty_fp)
@@ -67,18 +102,36 @@ impl CrateImplDefs {
                     None => {
                         let self_ty = db.impl_self_ty(impl_id);
                         if let Some(self_ty_fp) = TyFingerprint::for_impl(&self_ty.value) {
-                            res.impls.entry(self_ty_fp).or_default().push(impl_id);
+                            self.inherent_impls.entry(self_ty_fp).or_default().push(impl_id);
                         }
                     }
                 }
             }
         }
+    }
 
-        Arc::new(res)
+    fn merge(&mut self, other: &Self) {
+        for (fp, impls) in &other.inherent_impls {
+            let vec = self.inherent_impls.entry(*fp).or_default();
+            vec.extend(impls);
+            vec.sort();
+            vec.dedup();
+        }
+
+        for (trait_, other_map) in &other.impls_by_trait {
+            let map = self.impls_by_trait.entry(*trait_).or_default();
+            for (fp, impls) in other_map {
+                let vec = map.entry(*fp).or_default();
+                vec.extend(impls);
+                vec.sort();
+                vec.dedup();
+            }
+        }
     }
+
     pub fn lookup_impl_defs(&self, ty: &Ty) -> impl Iterator<Item = ImplId> + '_ {
         let fingerprint = TyFingerprint::for_impl(ty);
-        fingerprint.and_then(|f| self.impls.get(&f)).into_iter().flatten().copied()
+        fingerprint.and_then(|f| self.inherent_impls.get(&f)).into_iter().flatten().copied()
     }
 
     pub fn lookup_impl_defs_for_trait(&self, tr: TraitId) -> impl Iterator<Item = ImplId> + '_ {
@@ -110,7 +163,7 @@ impl CrateImplDefs {
     }
 
     pub fn all_impls<'a>(&'a self) -> impl Iterator<Item = ImplId> + 'a {
-        self.impls
+        self.inherent_impls
             .values()
             .chain(self.impls_by_trait.values().flat_map(|m| m.values()))
             .flatten()
diff --git a/crates/ra_hir_ty/src/tests/regression.rs b/crates/ra_hir_ty/src/tests/regression.rs
index 1f004bd63..4da2e972b 100644
--- a/crates/ra_hir_ty/src/tests/regression.rs
+++ b/crates/ra_hir_ty/src/tests/regression.rs
@@ -633,3 +633,154 @@ where
     "###
     );
 }
+
+#[test]
+fn issue_4953() {
+    assert_snapshot!(
+        infer(r#"
+pub struct Foo(pub i64);
+impl Foo {
+    fn test() -> Self { Self(0i64) }
+}
+"#),
+        @r###"
+    59..73 '{ Self(0i64) }': Foo
+    61..65 'Self': Foo(i64) -> Foo
+    61..71 'Self(0i64)': Foo
+    66..70 '0i64': i64
+    "###
+    );
+    assert_snapshot!(
+        infer(r#"
+pub struct Foo<T>(pub T);
+impl Foo<i64> {
+    fn test() -> Self { Self(0i64) }
+}
+"#),
+        @r###"
+    65..79 '{ Self(0i64) }': Foo<i64>
+    67..71 'Self': Foo<i64>(i64) -> Foo<i64>
+    67..77 'Self(0i64)': Foo<i64>
+    72..76 '0i64': i64
+    "###
+    );
+}
+
+#[test]
+fn issue_4931() {
+    assert_snapshot!(
+        infer(r#"
+trait Div<T> {
+    type Output;
+}
+
+trait CheckedDiv: Div<()> {}
+
+trait PrimInt: CheckedDiv<Output = ()> {
+    fn pow(self);
+}
+
+fn check<T: PrimInt>(i: T) {
+    i.pow();
+}
+"#),
+        @r###"
+    118..122 'self': Self
+    149..150 'i': T
+    155..171 '{     ...w(); }': ()
+    161..162 'i': T
+    161..168 'i.pow()': ()
+    "###
+    );
+}
+
+#[test]
+fn issue_4885() {
+    assert_snapshot!(
+        infer(r#"
+#[lang = "coerce_unsized"]
+pub trait CoerceUnsized<T> {}
+
+trait Future {
+    type Output;
+}
+trait Foo<R> {
+    type Bar;
+}
+fn foo<R, K>(key: &K) -> impl Future<Output = K::Bar>
+where
+    K: Foo<R>,
+{
+    bar(key)
+}
+fn bar<R, K>(key: &K) -> impl Future<Output = K::Bar>
+where
+    K: Foo<R>,
+{
+}
+"#),
+        @r###"
+    137..140 'key': &K
+    199..215 '{     ...key) }': impl Future<Output = <K as Foo<R>>::Bar>
+    205..208 'bar': fn bar<R, K>(&K) -> impl Future<Output = <K as Foo<R>>::Bar>
+    205..213 'bar(key)': impl Future<Output = <K as Foo<R>>::Bar>
+    209..212 'key': &K
+    229..232 'key': &K
+    291..294 '{ }': ()
+    "###
+    );
+}
+
+#[test]
+fn issue_4800() {
+    assert_snapshot!(
+        infer(r#"
+trait Debug {}
+
+struct Foo<T>;
+
+type E1<T> = (T, T, T);
+type E2<T> = E1<E1<E1<(T, T, T)>>>;
+
+impl Debug for Foo<E2<()>> {}
+
+struct Request;
+
+pub trait Future {
+    type Output;
+}
+
+pub struct PeerSet<D>;
+
+impl<D> Service<Request> for PeerSet<D>
+where
+    D: Discover,
+    D::Key: Debug,
+{
+    type Error = ();
+    type Future = dyn Future<Output = Self::Error>;
+
+    fn call(&mut self) -> Self::Future {
+        loop {}
+    }
+}
+
+pub trait Discover {
+    type Key;
+}
+
+pub trait Service<Request> {
+    type Error;
+    type Future: Future<Output = Self::Error>;
+    fn call(&mut self) -> Self::Future;
+}
+"#),
+        @r###"
+    380..384 'self': &mut PeerSet<D>
+    402..425 '{     ...     }': dyn Future<Output = ()>
+    412..419 'loop {}': !
+    417..419 '{}': ()
+    576..580 'self': &mut Self
+    "###
+    );
+}
diff --git a/crates/ra_hir_ty/src/tests/traits.rs b/crates/ra_hir_ty/src/tests/traits.rs
index e81193a3c..961be4abd 100644
--- a/crates/ra_hir_ty/src/tests/traits.rs
+++ b/crates/ra_hir_ty/src/tests/traits.rs
@@ -2888,3 +2888,226 @@ impl<A: Step> iter::Iterator for ops::Range<A> {
     );
     assert_eq!(t, "i32");
 }
+
+#[test]
+fn infer_closure_arg() {
+    assert_snapshot!(
+        infer(
+            r#"
+            //- /lib.rs
+
+            enum Option<T> {
+                None,
+                Some(T)
+            }
+
+            fn foo() {
+                let s = Option::None;
+                let f = |x: Option<i32>| {};
+                (&f)(s)
+            }
+        "#
+        ),
+        @r###"
+    137..259 '{     ...     }': ()
+    159..160 's': Option<i32>
+    163..175 'Option::None': Option<i32>
+    197..198 'f': |Option<i32>| -> ()
+    201..220 '|x: Op...2>| {}': |Option<i32>| -> ()
+    202..203 'x': Option<i32>
+    218..220 '{}': ()
+    238..245 '(&f)(s)': ()
+    239..241 '&f': &|Option<i32>| -> ()
+    240..241 'f': |Option<i32>| -> ()
+    243..244 's': Option<i32>
+    "###
+    );
+}
+
+#[test]
+fn infer_fn_trait_arg() {
+    assert_snapshot!(
+        infer(
+            r#"
+            //- /lib.rs deps:std
+
+            #[lang = "fn_once"]
+            pub trait FnOnce<Args> {
+                type Output;
+
+                extern "rust-call" fn call_once(&self, args: Args) -> Self::Output;
+            }
+
+            #[lang = "fn"]
+            pub trait Fn<Args>:FnOnce<Args> {
+                extern "rust-call" fn call(&self, args: Args) -> Self::Output;
+            }
+
+            enum Option<T> {
+                None,
+                Some(T)
+            }
+
+            fn foo<F, T>(f: F) -> T
+            where
+                F: Fn(Option<i32>) -> T,
+            {
+                let s = None;
+                f(s)
+            }
+        "#
+        ),
+        @r###"
+    183..187 'self': &Self
+    189..193 'args': Args
+    350..354 'self': &Self
+    356..360 'args': Args
+    515..516 'f': F
+    597..663 '{     ...     }': T
+    619..620 's': Option<i32>
+    623..627 'None': Option<i32>
+    645..646 'f': F
+    645..649 'f(s)': T
+    647..648 's': Option<i32>
+    "###
+    );
+}
+
+#[test]
+fn infer_box_fn_arg() {
+    assert_snapshot!(
+        infer(
+            r#"
+            //- /lib.rs deps:std
+
+            #[lang = "fn_once"]
+            pub trait FnOnce<Args> {
+                type Output;
+
+                extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
+            }
+
+            #[lang = "deref"]
+            pub trait Deref {
+                type Target: ?Sized;
+
+                fn deref(&self) -> &Self::Target;
+            }
+
+            #[lang = "owned_box"]
+            pub struct Box<T: ?Sized> {
+                inner: *mut T,
+            }
+
+            impl<T: ?Sized> Deref for Box<T> {
+                type Target = T;
+
+                fn deref(&self) -> &T {
+                    &self.inner
+                }
+            }
+
+            enum Option<T> {
+                None,
+                Some(T)
+            }
+
+            fn foo() {
+                let s = Option::None;
+                let f: Box<dyn FnOnce(&Option<i32>)> = box (|ps| {});
+                f(&s)
+            }
+        "#
+        ),
+        @r###"
+    182..186 'self': Self
+    188..192 'args': Args
+    356..360 'self': &Self
+    622..626 'self': &Box<T>
+    634..685 '{     ...     }': &T
+    656..667 '&self.inner': &*mut T
+    657..661 'self': &Box<T>
+    657..667 'self.inner': *mut T
+    812..957 '{     ...     }': FnOnce::Output<dyn FnOnce<(&Option<i32>,)>, (&Option<i32>,)>
+    834..835 's': Option<i32>
+    838..850 'Option::None': Option<i32>
+    872..873 'f': Box<dyn FnOnce<(&Option<i32>,)>>
+    907..920 'box (|ps| {})': Box<|{unknown}| -> ()>
+    912..919 '|ps| {}': |{unknown}| -> ()
+    913..915 'ps': {unknown}
+    917..919 '{}': ()
+    938..939 'f': Box<dyn FnOnce<(&Option<i32>,)>>
+    938..943 'f(&s)': FnOnce::Output<dyn FnOnce<(&Option<i32>,)>, (&Option<i32>,)>
+    940..942 '&s': &Option<i32>
+    941..942 's': Option<i32>
+    "###
+    );
+}
+
+#[test]
+fn infer_dyn_fn_output() {
+    assert_snapshot!(
+        infer(
+            r#"
+            //- /lib.rs deps:std
+
+            #[lang = "fn_once"]
+            pub trait FnOnce<Args> {
+                type Output;
+
+                extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
+            }
+
+            #[lang = "fn"]
+            pub trait Fn<Args>:FnOnce<Args> {
+                extern "rust-call" fn call(&self, args: Args) -> Self::Output;
+            }
+
+            #[lang = "deref"]
+            pub trait Deref {
+                type Target: ?Sized;
+
+                fn deref(&self) -> &Self::Target;
+            }
+
+            #[lang = "owned_box"]
+            pub struct Box<T: ?Sized> {
+                inner: *mut T,
+            }
+
+            impl<T: ?Sized> Deref for Box<T> {
+                type Target = T;
+
+                fn deref(&self) -> &T {
+                    &self.inner
+                }
+            }
+
+            fn foo() {
+                let f: Box<dyn Fn() -> i32> = box(|| 5);
+                let x = f();
+            }
+        "#
+        ),
+        @r###"
+    182..186 'self': Self
+    188..192 'args': Args
+    349..353 'self': &Self
+    355..359 'args': Args
+    523..527 'self': &Self
+    789..793 'self': &Box<T>
+    801..852 '{     ...     }': &T
+    823..834 '&self.inner': &*mut T
+    824..828 'self': &Box<T>
+    824..834 'self.inner': *mut T
+    889..990 '{     ...     }': ()
+    911..912 'f': Box<dyn Fn<(), Output = i32>>
+    937..946 'box(|| 5)': Box<|| -> i32>
+    941..945 '|| 5': || -> i32
+    944..945 '5': i32
+    968..969 'x': FnOnce::Output<dyn Fn<(), Output = i32>, ()>
+    972..973 'f': Box<dyn Fn<(), Output = i32>>
+    972..975 'f()': FnOnce::Output<dyn Fn<(), Output = i32>, ()>
+    "###
+    );
+}
diff --git a/crates/ra_hir_ty/src/traits.rs b/crates/ra_hir_ty/src/traits.rs
index 6bc6d474c..6f43c3a22 100644
--- a/crates/ra_hir_ty/src/traits.rs
+++ b/crates/ra_hir_ty/src/traits.rs
@@ -2,12 +2,13 @@
 use std::{panic, sync::Arc};
 
 use chalk_ir::cast::Cast;
-use hir_def::{expr::ExprId, DefWithBodyId, ImplId, TraitId, TypeAliasId};
+use hir_def::{
+    expr::ExprId, lang_item::LangItemTarget, DefWithBodyId, ImplId, TraitId, TypeAliasId,
+};
 use ra_db::{impl_intern_key, salsa, CrateId};
 use ra_prof::profile;
-use rustc_hash::FxHashSet;
 
-use crate::{db::HirDatabase, method_resolution::TyFingerprint, DebruijnIndex};
+use crate::{db::HirDatabase, DebruijnIndex};
 
 use super::{Canonical, GenericPredicate, HirDisplay, ProjectionTy, TraitRef, Ty, TypeWalk};
 
@@ -36,34 +37,6 @@ fn create_chalk_solver() -> chalk_solve::Solver<Interner> {
     solver_choice.into_solver()
 }
 
-/// Collects impls for the given trait in the whole dependency tree of `krate`.
-pub(crate) fn impls_for_trait_query(
-    db: &dyn HirDatabase,
-    krate: CrateId,
-    trait_: TraitId,
-    self_ty_fp: Option<TyFingerprint>,
-) -> Arc<[ImplId]> {
-    // FIXME: We could be a lot smarter here - because of the orphan rules and
-    // the fact that the trait and the self type need to be in the dependency
-    // tree of a crate somewhere for an impl to exist, we could skip looking in
-    // a lot of crates completely
-    let mut impls = FxHashSet::default();
-    // We call the query recursively here. On the one hand, this means we can
-    // reuse results from queries for different crates; on the other hand, this
-    // will only ever get called for a few crates near the root of the tree (the
-    // ones the user is editing), so this may actually be a waste of memory. I'm
-    // doing it like this mainly for simplicity for now.
-    for dep in &db.crate_graph()[krate].dependencies {
-        impls.extend(db.impls_for_trait(dep.crate_id, trait_, self_ty_fp).iter());
-    }
-    let crate_impl_defs = db.impls_in_crate(krate);
-    match self_ty_fp {
-        Some(fp) => impls.extend(crate_impl_defs.lookup_impl_defs_for_trait_and_ty(trait_, fp)),
-        None => impls.extend(crate_impl_defs.lookup_impl_defs_for_trait(trait_)),
-    }
-    impls.into_iter().collect()
-}
-
 /// A set of clauses that we assume to be true. E.g. if we are inside this function:
 /// ```rust
 /// fn foo<T: Default>(t: T) {}
@@ -298,6 +271,14 @@ impl FnTrait {
             FnTrait::Fn => "fn",
         }
     }
+
+    pub fn get_id(&self, db: &dyn HirDatabase, krate: CrateId) -> Option<TraitId> {
+        let target = db.lang_item(krate, self.lang_item_name().into())?;
+        match target {
+            LangItemTarget::TraitId(t) => Some(t),
+            _ => None,
+        }
+    }
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
diff --git a/crates/ra_hir_ty/src/traits/builtin.rs b/crates/ra_hir_ty/src/traits/builtin.rs
index 88a422d2c..6d5f2d46a 100644
--- a/crates/ra_hir_ty/src/traits/builtin.rs
+++ b/crates/ra_hir_ty/src/traits/builtin.rs
@@ -40,7 +40,7 @@ pub(super) fn get_builtin_impls(
     if let Ty::Apply(ApplicationTy { ctor: TypeCtor::Closure { def, expr }, .. }) = ty {
         for &fn_trait in [super::FnTrait::FnOnce, super::FnTrait::FnMut, super::FnTrait::Fn].iter()
         {
-            if let Some(actual_trait) = get_fn_trait(db, krate, fn_trait) {
+            if let Some(actual_trait) = fn_trait.get_id(db, krate) {
                 if trait_ == actual_trait {
                     let impl_ = super::ClosureFnTraitImplData { def: *def, expr: *expr, fn_trait };
                     if check_closure_fn_trait_impl_prerequisites(db, krate, impl_) {
@@ -128,7 +128,7 @@ fn check_closure_fn_trait_impl_prerequisites(
     data: super::ClosureFnTraitImplData,
 ) -> bool {
     // the respective Fn/FnOnce/FnMut trait needs to exist
-    if get_fn_trait(db, krate, data.fn_trait).is_none() {
+    if data.fn_trait.get_id(db, krate).is_none() {
         return false;
     }
 
@@ -136,7 +136,7 @@ fn check_closure_fn_trait_impl_prerequisites(
     // the traits having no type params, FnOnce being a supertrait
 
     // the FnOnce trait needs to exist and have an assoc type named Output
-    let fn_once_trait = match get_fn_trait(db, krate, super::FnTrait::FnOnce) {
+    let fn_once_trait = match (super::FnTrait::FnOnce).get_id(db, krate) {
         Some(t) => t,
         None => return false,
     };
@@ -151,7 +151,9 @@ fn closure_fn_trait_impl_datum(
     // for some closure |X, Y| -> Z:
     // impl<T, U, V> Fn<(T, U)> for closure<fn(T, U) -> V> { Output = V }
 
-    let trait_ = get_fn_trait(db, krate, data.fn_trait) // get corresponding fn trait
+    let trait_ = data
+        .fn_trait
+        .get_id(db, krate) // get corresponding fn trait
         // the existence of the Fn trait has been checked before
         .expect("fn trait for closure impl missing");
 
@@ -211,7 +213,7 @@ fn closure_fn_trait_output_assoc_ty_value(
     let output_ty = Ty::Bound(BoundVar::new(DebruijnIndex::INNERMOST, num_args.into()));
 
     let fn_once_trait =
-        get_fn_trait(db, krate, super::FnTrait::FnOnce).expect("assoc ty value should not exist");
+        (super::FnTrait::FnOnce).get_id(db, krate).expect("assoc ty value should not exist");
 
     let output_ty_id = db
         .trait_data(fn_once_trait)
@@ -360,14 +362,6 @@ fn super_trait_object_unsize_impl_datum(
     BuiltinImplData { num_vars, trait_ref, where_clauses: Vec::new(), assoc_ty_values: Vec::new() }
 }
 
-fn get_fn_trait(db: &dyn HirDatabase, krate: CrateId, fn_trait: super::FnTrait) -> Option<TraitId> {
-    let target = db.lang_item(krate, fn_trait.lang_item_name().into())?;
-    match target {
-        LangItemTarget::TraitId(t) => Some(t),
-        _ => None,
-    }
-}
-
 fn get_unsize_trait(db: &dyn HirDatabase, krate: CrateId) -> Option<TraitId> {
     let target = db.lang_item(krate, "unsize".into())?;
     match target {
diff --git a/crates/ra_hir_ty/src/traits/chalk.rs b/crates/ra_hir_ty/src/traits/chalk.rs
index a72a82f5a..2f35d6d49 100644
--- a/crates/ra_hir_ty/src/traits/chalk.rs
+++ b/crates/ra_hir_ty/src/traits/chalk.rs
@@ -74,14 +74,26 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
         // Note: Since we're using impls_for_trait, only impls where the trait
         // can be resolved should ever reach Chalk. `impl_datum` relies on that
         // and will panic if the trait can't be resolved.
-        let mut result: Vec<_> = self
-            .db
-            .impls_for_trait(self.krate, trait_, self_ty_fp)
-            .iter()
-            .copied()
-            .map(Impl::ImplDef)
-            .map(|impl_| impl_.to_chalk(self.db))
-            .collect();
+        let in_deps = self.db.impls_from_deps(self.krate);
+        let in_self = self.db.impls_in_crate(self.krate);
+        let impl_maps = [in_deps, in_self];
+
+        let id_to_chalk = |id: hir_def::ImplId| Impl::ImplDef(id).to_chalk(self.db);
+
+        let mut result: Vec<_> = match self_ty_fp {
+            Some(fp) => impl_maps
+                .iter()
+                .flat_map(|crate_impl_defs| {
+                    crate_impl_defs.lookup_impl_defs_for_trait_and_ty(trait_, fp).map(id_to_chalk)
+                })
+                .collect(),
+            None => impl_maps
+                .iter()
+                .flat_map(|crate_impl_defs| {
+                    crate_impl_defs.lookup_impl_defs_for_trait(trait_).map(id_to_chalk)
+                })
+                .collect(),
+        };
 
         let arg: Option<Ty> =
             parameters.get(1).map(|p| from_chalk(self.db, p.assert_ty_ref(&Interner).clone()));
diff --git a/crates/ra_hir_ty/src/utils.rs b/crates/ra_hir_ty/src/utils.rs
index f98350bf9..c45820ff0 100644
--- a/crates/ra_hir_ty/src/utils.rs
+++ b/crates/ra_hir_ty/src/utils.rs
@@ -143,13 +143,14 @@ pub(super) fn find_super_trait_path(
 }
 
 pub(super) fn associated_type_by_name_including_super_traits(
-    db: &dyn DefDatabase,
-    trait_: TraitId,
+    db: &dyn HirDatabase,
+    trait_ref: TraitRef,
     name: &Name,
-) -> Option<TypeAliasId> {
-    all_super_traits(db, trait_)
-        .into_iter()
-        .find_map(|t| db.trait_data(t).associated_type_by_name(name))
+) -> Option<(TraitRef, TypeAliasId)> {
+    all_super_trait_refs(db, trait_ref).into_iter().find_map(|t| {
+        let assoc_type = db.trait_data(t.trait_).associated_type_by_name(name)?;
+        Some((t, assoc_type))
+    })
 }
 
 pub(super) fn variant_data(db: &dyn DefDatabase, var: VariantId) -> Arc<VariantData> {
@@ -176,6 +177,7 @@ pub(crate) fn generics(db: &dyn DefDatabase, def: GenericDefId) -> Generics {
     Generics { def, params: db.generic_params(def), parent_generics }
 }
 
+#[derive(Debug)]
 pub(crate) struct Generics {
     def: GenericDefId,
     pub(crate) params: Arc<GenericParams>,
diff --git a/crates/ra_ide/src/diagnostics.rs b/crates/ra_ide/src/diagnostics.rs
index fd9abb55b..a88a978d7 100644
--- a/crates/ra_ide/src/diagnostics.rs
+++ b/crates/ra_ide/src/diagnostics.rs
@@ -8,7 +8,7 @@ use std::cell::RefCell;
 
 use hir::{
     diagnostics::{AstDiagnostic, Diagnostic as _, DiagnosticSink},
-    Semantics,
+    HasSource, HirDisplay, Semantics, VariantDef,
 };
 use itertools::Itertools;
 use ra_db::SourceDatabase;
@@ -16,7 +16,7 @@ use ra_ide_db::RootDatabase;
 use ra_prof::profile;
 use ra_syntax::{
     algo,
-    ast::{self, make, AstNode},
+    ast::{self, edit::IndentLevel, make, AstNode},
     SyntaxNode, TextRange, T,
 };
 use ra_text_edit::{TextEdit, TextEditBuilder};
@@ -119,7 +119,16 @@ pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic>
             severity: Severity::Error,
             fix: Some(fix),
         })
+    })
+    .on::<hir::diagnostics::NoSuchField, _>(|d| {
+        res.borrow_mut().push(Diagnostic {
+            range: sema.diagnostics_range(d).range,
+            message: d.message(),
+            severity: Severity::Error,
+            fix: missing_struct_field_fix(&sema, file_id, d),
+        })
     });
+
     if let Some(m) = sema.to_module_def(file_id) {
         m.diagnostics(db, &mut sink);
     };
@@ -127,6 +136,68 @@ pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic>
     res.into_inner()
 }
 
+fn missing_struct_field_fix(
+    sema: &Semantics<RootDatabase>,
+    file_id: FileId,
+    d: &hir::diagnostics::NoSuchField,
+) -> Option<Fix> {
+    let record_expr = sema.ast(d);
+
+    let record_lit = ast::RecordLit::cast(record_expr.syntax().parent()?.parent()?)?;
+    let def_id = sema.resolve_variant(record_lit)?;
+    let module;
+    let record_fields = match VariantDef::from(def_id) {
+        VariantDef::Struct(s) => {
+            module = s.module(sema.db);
+            let source = s.source(sema.db);
+            let fields = source.value.field_def_list()?;
+            record_field_def_list(fields)?
+        }
+        VariantDef::Union(u) => {
+            module = u.module(sema.db);
+            let source = u.source(sema.db);
+            source.value.record_field_def_list()?
+        }
+        VariantDef::EnumVariant(e) => {
+            module = e.module(sema.db);
+            let source = e.source(sema.db);
+            let fields = source.value.field_def_list()?;
+            record_field_def_list(fields)?
+        }
+    };
+
+    let new_field_type = sema.type_of_expr(&record_expr.expr()?)?;
+    let new_field = make::record_field_def(
+        record_expr.field_name()?,
+        make::type_ref(&new_field_type.display_source_code(sema.db, module.into()).ok()?),
+    );
+
+    let last_field = record_fields.fields().last()?;
+    let last_field_syntax = last_field.syntax();
+    let indent = IndentLevel::from_node(last_field_syntax);
+
+    let mut new_field = format!("\n{}{}", indent, new_field);
+
+    let needs_comma = !last_field_syntax.to_string().ends_with(",");
+    if needs_comma {
+        new_field = format!(",{}", new_field);
+    }
+
+    let source_change = SourceFileEdit {
+        file_id,
+        edit: TextEdit::insert(last_field_syntax.text_range().end(), new_field),
+    };
+    let fix = Fix::new("Create field", source_change.into());
+    return Some(fix);
+
+    fn record_field_def_list(field_def_list: ast::FieldDefList) -> Option<ast::RecordFieldDefList> {
+        match field_def_list {
+            ast::FieldDefList::RecordFieldDefList(it) => Some(it),
+            ast::FieldDefList::TupleFieldDefList(_) => None,
+        }
+    }
+}
+
 fn check_unnecessary_braces_in_use_statement(
     acc: &mut Vec<Diagnostic>,
     file_id: FileId,
@@ -791,4 +862,27 @@ fn main() {
             check_struct_shorthand_initialization,
         );
     }
+
+    #[test]
+    fn test_add_field_from_usage() {
+        check_apply_diagnostic_fix(
+            r"
+            fn main() {
+                Foo { bar: 3, baz: false};
+            }
+            struct Foo {
+                bar: i32
+            }
+            ",
+            r"
+            fn main() {
+                Foo { bar: 3, baz: false};
+            }
+            struct Foo {
+                bar: i32,
+                baz: bool
+            }
+            ",
+        )
+    }
 }
diff --git a/crates/ra_ide/src/display/navigation_target.rs b/crates/ra_ide/src/display/navigation_target.rs
index c7bb1e69f..0b52b01ab 100644
--- a/crates/ra_ide/src/display/navigation_target.rs
+++ b/crates/ra_ide/src/display/navigation_target.rs
@@ -135,8 +135,8 @@ impl NavigationTarget {
         db: &RootDatabase,
         node: InFile<&dyn ast::NameOwner>,
     ) -> NavigationTarget {
-        //FIXME: use `_` instead of empty string
-        let name = node.value.name().map(|it| it.text().clone()).unwrap_or_default();
+        let name =
+            node.value.name().map(|it| it.text().clone()).unwrap_or_else(|| SmolStr::new("_"));
         let focus_range =
             node.value.name().map(|it| original_range(db, node.with_value(it.syntax())).range);
         let frange = original_range(db, node.map(|it| it.syntax()));
@@ -150,6 +150,25 @@ impl NavigationTarget {
         )
     }
 
+    /// Allows `NavigationTarget` to be created from a `DocCommentsOwner` and a `NameOwner`
+    pub(crate) fn from_doc_commented(
+        db: &RootDatabase,
+        named: InFile<&dyn ast::NameOwner>,
+        node: InFile<&dyn ast::DocCommentsOwner>,
+    ) -> NavigationTarget {
+        let name =
+            named.value.name().map(|it| it.text().clone()).unwrap_or_else(|| SmolStr::new("_"));
+        let frange = original_range(db, node.map(|it| it.syntax()));
+
+        NavigationTarget::from_syntax(
+            frange.file_id,
+            name,
+            None,
+            frange.range,
+            node.value.syntax().kind(),
+        )
+    }
+
     fn from_syntax(
         file_id: FileId,
         name: SmolStr,
diff --git a/crates/ra_ide/src/hover.rs b/crates/ra_ide/src/hover.rs
index ad78b7671..d870e4cbc 100644
--- a/crates/ra_ide/src/hover.rs
+++ b/crates/ra_ide/src/hover.rs
@@ -2,7 +2,7 @@ use std::iter::once;
 
 use hir::{
     Adt, AsAssocItem, AssocItemContainer, Documentation, FieldSource, HasSource, HirDisplay,
-    ModuleDef, ModuleSource, Semantics,
+    Module, ModuleDef, ModuleSource, Semantics,
 };
 use itertools::Itertools;
 use ra_db::SourceDatabase;
@@ -13,7 +13,9 @@ use ra_ide_db::{
 use ra_syntax::{ast, match_ast, AstNode, SyntaxKind::*, SyntaxToken, TokenAtOffset};
 
 use crate::{
-    display::{macro_label, rust_code_markup, rust_code_markup_with_doc, ShortLabel, ToNav},
+    display::{
+        macro_label, rust_code_markup, rust_code_markup_with_doc, ShortLabel, ToNav, TryToNav,
+    },
     runnables::runnable,
     FileId, FilePosition, NavigationTarget, RangeInfo, Runnable,
 };
@@ -24,19 +26,21 @@ pub struct HoverConfig {
     pub implementations: bool,
     pub run: bool,
     pub debug: bool,
+    pub goto_type_def: bool,
 }
 
 impl Default for HoverConfig {
     fn default() -> Self {
-        Self { implementations: true, run: true, debug: true }
+        Self { implementations: true, run: true, debug: true, goto_type_def: true }
     }
 }
 
 impl HoverConfig {
-    pub const NO_ACTIONS: Self = Self { implementations: false, run: false, debug: false };
+    pub const NO_ACTIONS: Self =
+        Self { implementations: false, run: false, debug: false, goto_type_def: false };
 
     pub fn any(&self) -> bool {
-        self.implementations || self.runnable()
+        self.implementations || self.runnable() || self.goto_type_def
     }
 
     pub fn none(&self) -> bool {
@@ -52,6 +56,13 @@ impl HoverConfig {
 pub enum HoverAction {
     Runnable(Runnable),
     Implementaion(FilePosition),
+    GoToType(Vec<HoverGotoTypeData>),
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct HoverGotoTypeData {
+    pub mod_path: String,
+    pub nav: NavigationTarget,
 }
 
 /// Contains the results when hovering over an item
@@ -138,6 +149,10 @@ pub(crate) fn hover(db: &RootDatabase, position: FilePosition) -> Option<RangeIn
                 res.push_action(action);
             }
 
+            if let Some(action) = goto_type_action(db, name_kind) {
+                res.push_action(action);
+            }
+
             return Some(RangeInfo::new(range, res));
         }
     }
@@ -218,6 +233,44 @@ fn runnable_action(
     }
 }
 
+fn goto_type_action(db: &RootDatabase, def: Definition) -> Option<HoverAction> {
+    match def {
+        Definition::Local(it) => {
+            let mut targets: Vec<ModuleDef> = Vec::new();
+            let mut push_new_def = |item: ModuleDef| {
+                if !targets.contains(&item) {
+                    targets.push(item);
+                }
+            };
+
+            it.ty(db).walk(db, |t| {
+                if let Some(adt) = t.as_adt() {
+                    push_new_def(adt.into());
+                } else if let Some(trait_) = t.as_dyn_trait() {
+                    push_new_def(trait_.into());
+                } else if let Some(traits) = t.as_impl_traits(db) {
+                    traits.into_iter().for_each(|it| push_new_def(it.into()));
+                } else if let Some(trait_) = t.as_associated_type_parent_trait(db) {
+                    push_new_def(trait_.into());
+                }
+            });
+
+            let targets = targets
+                .into_iter()
+                .filter_map(|it| {
+                    Some(HoverGotoTypeData {
+                        mod_path: mod_path(db, &it)?,
+                        nav: it.try_to_nav(db)?,
+                    })
+                })
+                .collect();
+
+            Some(HoverAction::GoToType(targets))
+        }
+        _ => None,
+    }
+}
+
 fn hover_text(
     docs: Option<String>,
     desc: Option<String>,
@@ -248,25 +301,31 @@ fn definition_owner_name(db: &RootDatabase, def: &Definition) -> Option<String>
     .map(|name| name.to_string())
 }
 
-fn determine_mod_path(db: &RootDatabase, def: &Definition) -> Option<String> {
-    let mod_path = def.module(db).map(|module| {
-        once(db.crate_graph()[module.krate().into()].display_name.as_ref().map(ToString::to_string))
-            .chain(
-                module
-                    .path_to_root(db)
-                    .into_iter()
-                    .rev()
-                    .map(|it| it.name(db).map(|name| name.to_string())),
-            )
-            .chain(once(definition_owner_name(db, def)))
-            .flatten()
-            .join("::")
-    });
-    mod_path
+fn determine_mod_path(db: &RootDatabase, module: Module, name: Option<String>) -> String {
+    once(db.crate_graph()[module.krate().into()].display_name.as_ref().map(ToString::to_string))
+        .chain(
+            module
+                .path_to_root(db)
+                .into_iter()
+                .rev()
+                .map(|it| it.name(db).map(|name| name.to_string())),
+        )
+        .chain(once(name))
+        .flatten()
+        .join("::")
+}
+
+// returns None only for ModuleDef::BuiltinType
+fn mod_path(db: &RootDatabase, item: &ModuleDef) -> Option<String> {
+    Some(determine_mod_path(db, item.module(db)?, item.name(db).map(|name| name.to_string())))
+}
+
+fn definition_mod_path(db: &RootDatabase, def: &Definition) -> Option<String> {
+    def.module(db).map(|module| determine_mod_path(db, module, definition_owner_name(db, def)))
 }
 
 fn hover_text_from_name_kind(db: &RootDatabase, def: Definition) -> Option<String> {
-    let mod_path = determine_mod_path(db, &def);
+    let mod_path = definition_mod_path(db, &def);
     return match def {
         Definition::Macro(it) => {
             let src = it.source(db);
@@ -1310,4 +1369,1045 @@ fn func(foo: i32) { if true { <|>foo; }; }
             ]
             "###);
     }
+
+    #[test]
+    fn test_hover_struct_has_goto_type_action() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /main.rs
+            struct S{ f1: u32 }
+
+            fn main() {
+                let s<|>t = S{ f1:0 };
+            }
+            ",
+            &["S"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "S",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..19,
+                                name: "S",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    7..8,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct S",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+            "###);
+    }
+
+    #[test]
+    fn test_hover_generic_struct_has_goto_type_actions() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /main.rs
+            struct Arg(u32);
+            struct S<T>{ f1: T }
+
+            fn main() {
+                let s<|>t = S{ f1:Arg(0) };
+            }
+            ",
+            &["S<Arg>"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "S",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 17..37,
+                                name: "S",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    24..25,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct S",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "Arg",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..16,
+                                name: "Arg",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    7..10,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct Arg",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+            "###);
+    }
+
+    #[test]
+    fn test_hover_generic_struct_has_flattened_goto_type_actions() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /main.rs
+            struct Arg(u32);
+            struct S<T>{ f1: T }
+
+            fn main() {
+                let s<|>t = S{ f1: S{ f1: Arg(0) } };
+            }
+            ",
+            &["S<S<Arg>>"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "S",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 17..37,
+                                name: "S",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    24..25,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct S",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "Arg",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..16,
+                                name: "Arg",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    7..10,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct Arg",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+            "###);
+    }
+
+    #[test]
+    fn test_hover_tuple_has_goto_type_actions() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /main.rs
+            struct A(u32);
+            struct B(u32);
+            mod M {
+                pub struct C(u32);
+            }
+
+            fn main() {
+                let s<|>t = (A(1), B(2), M::C(3) );
+            }
+            ",
+            &["(A, B, C)"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "A",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..14,
+                                name: "A",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    7..8,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct A",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "B",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 15..29,
+                                name: "B",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    22..23,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct B",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "M::C",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 42..60,
+                                name: "C",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    53..54,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "pub struct C",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+               "###);
+    }
+
+    #[test]
+    fn test_hover_return_impl_trait_has_goto_type_action() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /main.rs
+            trait Foo {}
+
+            fn foo() -> impl Foo {}
+
+            fn main() {
+                let s<|>t = foo();
+            }
+            ",
+            &["impl Foo"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "Foo",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..12,
+                                name: "Foo",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    6..9,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait Foo",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+            "###);
+    }
+
+    #[test]
+    fn test_hover_generic_return_impl_trait_has_goto_type_action() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /main.rs
+            trait Foo<T> {}
+            struct S;
+
+            fn foo() -> impl Foo<S> {}
+
+            fn main() {
+                let s<|>t = foo();
+            }
+            ",
+            &["impl Foo<S>"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "Foo",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..15,
+                                name: "Foo",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    6..9,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait Foo",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "S",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 16..25,
+                                name: "S",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    23..24,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct S",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+            "###);
+    }
+
+    #[test]
+    fn test_hover_return_impl_traits_has_goto_type_action() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /main.rs
+            trait Foo {}
+            trait Bar {}
+
+            fn foo() -> impl Foo + Bar {}
+
+            fn main() {
+                let s<|>t = foo();
+            }
+            ",
+            &["impl Foo + Bar"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "Foo",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..12,
+                                name: "Foo",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    6..9,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait Foo",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "Bar",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 13..25,
+                                name: "Bar",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    19..22,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait Bar",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+            "###);
+    }
+
+    #[test]
+    fn test_hover_generic_return_impl_traits_has_goto_type_action() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /main.rs
+            trait Foo<T> {}
+            trait Bar<T> {}
+            struct S1 {}
+            struct S2 {}
+
+            fn foo() -> impl Foo<S1> + Bar<S2> {}
+
+            fn main() {
+                let s<|>t = foo();
+            }
+            ",
+            &["impl Foo<S1> + Bar<S2>"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "Foo",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..15,
+                                name: "Foo",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    6..9,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait Foo",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "Bar",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 16..31,
+                                name: "Bar",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    22..25,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait Bar",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "S1",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 32..44,
+                                name: "S1",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    39..41,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct S1",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "S2",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 45..57,
+                                name: "S2",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    52..54,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct S2",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+               "###);
+    }
+
+    #[test]
+    fn test_hover_arg_impl_trait_has_goto_type_action() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /lib.rs
+            trait Foo {}
+            fn foo(ar<|>g: &impl Foo) {}
+            ",
+            &["&impl Foo"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "Foo",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..12,
+                                name: "Foo",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    6..9,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait Foo",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+            "###);
+    }
+
+    #[test]
+    fn test_hover_arg_impl_traits_has_goto_type_action() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /lib.rs
+            trait Foo {}
+            trait Bar<T> {}
+            struct S{}
+
+            fn foo(ar<|>g: &impl Foo + Bar<S>) {}
+            ",
+            &["&impl Foo + Bar<S>"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "Foo",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..12,
+                                name: "Foo",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    6..9,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait Foo",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "Bar",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 13..28,
+                                name: "Bar",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    19..22,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait Bar",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "S",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 29..39,
+                                name: "S",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    36..37,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct S",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+            "###);
+    }
+
+    #[test]
+    fn test_hover_arg_generic_impl_trait_has_goto_type_action() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /lib.rs
+            trait Foo<T> {}
+            struct S {}
+            fn foo(ar<|>g: &impl Foo<S>) {}
+            ",
+            &["&impl Foo<S>"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "Foo",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..15,
+                                name: "Foo",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    6..9,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait Foo",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "S",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 16..27,
+                                name: "S",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    23..24,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct S",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+            "###);
+    }
+
+    #[test]
+    fn test_hover_dyn_return_has_goto_type_action() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /main.rs
+            trait Foo {}
+            struct S;
+            impl Foo for S {}
+
+            struct B<T>{}
+
+            fn foo() -> B<dyn Foo> {}
+
+            fn main() {
+                let s<|>t = foo();
+            }
+            ",
+            &["B<dyn Foo>"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "B",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 41..54,
+                                name: "B",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    48..49,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct B",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "Foo",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..12,
+                                name: "Foo",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    6..9,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait Foo",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+            "###);
+    }
+
+    #[test]
+    fn test_hover_dyn_arg_has_goto_type_action() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /lib.rs
+            trait Foo {}
+            fn foo(ar<|>g: &dyn Foo) {}
+            ",
+            &["&dyn Foo"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "Foo",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..12,
+                                name: "Foo",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    6..9,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait Foo",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+            "###);
+    }
+
+    #[test]
+    fn test_hover_generic_dyn_arg_has_goto_type_action() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /lib.rs
+            trait Foo<T> {}
+            struct S {}
+            fn foo(ar<|>g: &dyn Foo<S>) {}
+            ",
+            &["&dyn Foo<S>"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "Foo",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..15,
+                                name: "Foo",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    6..9,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait Foo",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "S",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 16..27,
+                                name: "S",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    23..24,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct S",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+            "###);
+    }
+
+    #[test]
+    fn test_hover_goto_type_action_links_order() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /lib.rs
+            trait ImplTrait<T> {}
+            trait DynTrait<T> {}
+            struct B<T> {}
+            struct S {}
+
+            fn foo(a<|>rg: &impl ImplTrait<B<dyn DynTrait<B<S>>>>) {}
+            ",
+            &["&impl ImplTrait<B<dyn DynTrait<B<S>>>>"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "ImplTrait",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..21,
+                                name: "ImplTrait",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    6..15,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait ImplTrait",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "B",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 43..57,
+                                name: "B",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    50..51,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct B",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "DynTrait",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 22..42,
+                                name: "DynTrait",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    28..36,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait DynTrait",
+                                ),
+                                docs: None,
+                            },
+                        },
+                        HoverGotoTypeData {
+                            mod_path: "S",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 58..69,
+                                name: "S",
+                                kind: STRUCT_DEF,
+                                focus_range: Some(
+                                    65..66,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "struct S",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+            "###);
+    }
+
+    #[test]
+    fn test_hover_associated_type_has_goto_type_action() {
+        let (_, actions) = check_hover_result(
+            "
+            //- /main.rs
+            trait Foo {
+                type Item;
+                fn get(self) -> Self::Item {}
+            }
+
+            struct Bar{}
+            struct S{}
+
+            impl Foo for S{
+                type Item = Bar;
+            }
+
+            fn test() -> impl Foo {
+                S{}
+            }
+
+            fn main() {
+                let s<|>t = test().get();
+            }
+            ",
+            &["Foo::Item<impl Foo>"],
+        );
+        assert_debug_snapshot!(actions,
+            @r###"
+            [
+                GoToType(
+                    [
+                        HoverGotoTypeData {
+                            mod_path: "Foo",
+                            nav: NavigationTarget {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                full_range: 0..62,
+                                name: "Foo",
+                                kind: TRAIT_DEF,
+                                focus_range: Some(
+                                    6..9,
+                                ),
+                                container_name: None,
+                                description: Some(
+                                    "trait Foo",
+                                ),
+                                docs: None,
+                            },
+                        },
+                    ],
+                ),
+            ]
+            "###);
+    }
 }
diff --git a/crates/ra_ide/src/lib.rs b/crates/ra_ide/src/lib.rs
index 375da1f45..be9ab62c0 100644
--- a/crates/ra_ide/src/lib.rs
+++ b/crates/ra_ide/src/lib.rs
@@ -66,7 +66,7 @@ pub use crate::{
     display::{file_structure, FunctionSignature, NavigationTarget, StructureNode},
     expand_macro::ExpandedMacro,
     folding_ranges::{Fold, FoldKind},
-    hover::{HoverAction, HoverConfig, HoverResult},
+    hover::{HoverAction, HoverConfig, HoverGotoTypeData, HoverResult},
     inlay_hints::{InlayHint, InlayHintsConfig, InlayKind},
     references::{Declaration, Reference, ReferenceAccess, ReferenceKind, ReferenceSearchResult},
     runnables::{Runnable, RunnableKind, TestId},
@@ -82,7 +82,7 @@ pub use ra_db::{
     Canceled, CrateGraph, CrateId, Edition, FileId, FilePosition, FileRange, SourceRootId,
 };
 pub use ra_ide_db::{
-    change::{AnalysisChange, LibraryData},
+    change::AnalysisChange,
     line_index::{LineCol, LineIndex},
     search::SearchScope,
     source_change::{FileSystemEdit, SourceChange, SourceFileEdit},
diff --git a/crates/ra_ide/src/runnables.rs b/crates/ra_ide/src/runnables.rs
index fc57dc33d..8105ef373 100644
--- a/crates/ra_ide/src/runnables.rs
+++ b/crates/ra_ide/src/runnables.rs
@@ -171,7 +171,15 @@ fn runnable_fn(
     let cfg_exprs =
         attrs.by_key("cfg").tt_values().map(|subtree| ra_cfg::parse_cfg(subtree)).collect();
 
-    let nav = NavigationTarget::from_named(sema.db, InFile::new(file_id.into(), &fn_def));
+    let nav = if let RunnableKind::DocTest { .. } = kind {
+        NavigationTarget::from_doc_commented(
+            sema.db,
+            InFile::new(file_id.into(), &fn_def),
+            InFile::new(file_id.into(), &fn_def),
+        )
+    } else {
+        NavigationTarget::from_named(sema.db, InFile::new(file_id.into(), &fn_def))
+    };
     Some(Runnable { nav, kind, cfg_exprs })
 }
 
@@ -419,9 +427,7 @@ mod tests {
                     full_range: 22..64,
                     name: "foo",
                     kind: FN_DEF,
-                    focus_range: Some(
-                        56..59,
-                    ),
+                    focus_range: None,
                     container_name: None,
                     description: None,
                     docs: None,
@@ -486,9 +492,7 @@ mod tests {
                     full_range: 51..105,
                     name: "foo",
                     kind: FN_DEF,
-                    focus_range: Some(
-                        97..100,
-                    ),
+                    focus_range: None,
                     container_name: None,
                     description: None,
                     docs: None,
diff --git a/crates/ra_ide/src/snapshots/highlight_doctest.html b/crates/ra_ide/src/snapshots/highlight_doctest.html
index f92a0aba5..63199cdbe 100644
--- a/crates/ra_ide/src/snapshots/highlight_doctest.html
+++ b/crates/ra_ide/src/snapshots/highlight_doctest.html
@@ -39,49 +39,58 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 <span class="keyword">impl</span> <span class="struct">Foo</span> {
     <span class="keyword">pub</span> <span class="keyword">const</span> <span class="constant declaration">bar</span>: <span class="builtin_type">bool</span> = <span class="bool_literal">true</span>;
 
-    <span class="comment">/// Constructs a new `Foo`.</span>
-    <span class="comment">///</span>
-    <span class="comment">/// # Examples</span>
-    <span class="comment">///</span>
-    <span class="comment">/// ```</span>
-    <span class="comment">/// #</span> <span class="attribute">#![</span><span class="function attribute">allow</span><span class="attribute">(unused_mut)]</span>
-    <span class="comment">/// </span><span class="keyword">let</span> <span class="keyword">mut</span> <span class="variable declaration mutable">foo</span>: <span class="struct">Foo</span> = <span class="struct">Foo</span>::<span class="function">new</span>();
-    <span class="comment">/// ```</span>
+    <span class="comment documentation">/// Constructs a new `Foo`.</span>
+    <span class="comment documentation">///</span>
+    <span class="comment documentation">/// # Examples</span>
+    <span class="comment documentation">///</span>
+    <span class="comment documentation">/// ```</span>
+    <span class="comment documentation">/// #</span> <span class="attribute">#![</span><span class="function attribute">allow</span><span class="attribute">(unused_mut)]</span>
+    <span class="comment documentation">/// </span><span class="keyword">let</span> <span class="keyword">mut</span> <span class="variable declaration mutable">foo</span>: <span class="struct">Foo</span> = <span class="struct">Foo</span>::<span class="function">new</span>();
+    <span class="comment documentation">/// ```</span>
     <span class="keyword">pub</span> <span class="keyword">const</span> <span class="keyword">fn</span> <span class="function declaration">new</span>() -&gt; <span class="struct">Foo</span> {
         <span class="struct">Foo</span> { <span class="field">bar</span>: <span class="bool_literal">true</span> }
     }
 
-    <span class="comment">/// `bar` method on `Foo`.</span>
-    <span class="comment">///</span>
-    <span class="comment">/// # Examples</span>
-    <span class="comment">///</span>
-    <span class="comment">/// ```</span>
-    <span class="comment">/// </span><span class="keyword">use</span> <span class="module">x</span>::<span class="module">y</span>;
-    <span class="comment">///</span>
-    <span class="comment">/// </span><span class="keyword">let</span> <span class="variable declaration">foo</span> = <span class="struct">Foo</span>::<span class="function">new</span>();
-    <span class="comment">///</span>
-    <span class="comment">/// </span><span class="comment">// calls bar on foo</span>
-    <span class="comment">/// </span><span class="macro">assert!</span>(foo.bar());
-    <span class="comment">///</span>
-    <span class="comment">/// </span><span class="keyword">let</span> <span class="variable declaration">bar</span> = <span class="variable">foo</span>.<span class="field">bar</span> || <span class="struct">Foo</span>::<span class="constant">bar</span>;
-    <span class="comment">///</span>
-    <span class="comment">/// </span><span class="comment">/* multi-line
-    </span><span class="comment">/// </span><span class="comment">       comment */</span>
-    <span class="comment">///</span>
-    <span class="comment">/// </span><span class="keyword">let</span> <span class="variable declaration">multi_line_string</span> = <span class="string_literal">"Foo
-    </span><span class="comment">/// </span><span class="string_literal">  bar
-    </span><span class="comment">/// </span><span class="string_literal">         "</span>;
-    <span class="comment">///</span>
-    <span class="comment">/// ```</span>
-    <span class="comment">///</span>
-    <span class="comment">/// ```rust,no_run</span>
-    <span class="comment">/// </span><span class="keyword">let</span> <span class="variable declaration">foobar</span> = <span class="struct">Foo</span>::<span class="function">new</span>().<span class="function">bar</span>();
-    <span class="comment">/// ```</span>
-    <span class="comment">///</span>
-    <span class="comment">/// ```sh</span>
-    <span class="comment">/// echo 1</span>
-    <span class="comment">/// ```</span>
+    <span class="comment documentation">/// `bar` method on `Foo`.</span>
+    <span class="comment documentation">///</span>
+    <span class="comment documentation">/// # Examples</span>
+    <span class="comment documentation">///</span>
+    <span class="comment documentation">/// ```</span>
+    <span class="comment documentation">/// </span><span class="keyword">use</span> <span class="module">x</span>::<span class="module">y</span>;
+    <span class="comment documentation">///</span>
+    <span class="comment documentation">/// </span><span class="keyword">let</span> <span class="variable declaration">foo</span> = <span class="struct">Foo</span>::<span class="function">new</span>();
+    <span class="comment documentation">///</span>
+    <span class="comment documentation">/// </span><span class="comment">// calls bar on foo</span>
+    <span class="comment documentation">/// </span><span class="macro">assert!</span>(foo.bar());
+    <span class="comment documentation">///</span>
+    <span class="comment documentation">/// </span><span class="keyword">let</span> <span class="variable declaration">bar</span> = <span class="variable">foo</span>.<span class="field">bar</span> || <span class="struct">Foo</span>::<span class="constant">bar</span>;
+    <span class="comment documentation">///</span>
+    <span class="comment documentation">/// </span><span class="comment">/* multi-line
+    </span><span class="comment documentation">/// </span><span class="comment">       comment */</span>
+    <span class="comment documentation">///</span>
+    <span class="comment documentation">/// </span><span class="keyword">let</span> <span class="variable declaration">multi_line_string</span> = <span class="string_literal">"Foo
+    </span><span class="comment documentation">/// </span><span class="string_literal">  bar
+    </span><span class="comment documentation">/// </span><span class="string_literal">         "</span>;
+    <span class="comment documentation">///</span>
+    <span class="comment documentation">/// ```</span>
+    <span class="comment documentation">///</span>
+    <span class="comment documentation">/// ```rust,no_run</span>
+    <span class="comment documentation">/// </span><span class="keyword">let</span> <span class="variable declaration">foobar</span> = <span class="struct">Foo</span>::<span class="function">new</span>().<span class="function">bar</span>();
+    <span class="comment documentation">/// ```</span>
+    <span class="comment documentation">///</span>
+    <span class="comment documentation">/// ```sh</span>
+    <span class="comment documentation">/// echo 1</span>
+    <span class="comment documentation">/// ```</span>
     <span class="keyword">pub</span> <span class="keyword">fn</span> <span class="function declaration">foo</span>(&<span class="self_keyword">self</span>) -&gt; <span class="builtin_type">bool</span> {
         <span class="bool_literal">true</span>
     }
+}
+
+<span class="comment documentation">/// ```</span>
+<span class="comment documentation">/// </span><span class="macro">noop!</span>(<span class="numeric_literal">1</span>);
+<span class="comment documentation">/// ```</span>
+<span class="macro">macro_rules!</span> <span class="macro declaration">noop</span> {
+    ($expr:expr) =&gt; {
+        $expr
+    }
 }</code></pre>
\ No newline at end of file
diff --git a/crates/ra_ide/src/status.rs b/crates/ra_ide/src/status.rs
index 5b7992920..45411b357 100644
--- a/crates/ra_ide/src/status.rs
+++ b/crates/ra_ide/src/status.rs
@@ -16,6 +16,7 @@ use ra_prof::{memory_usage, Bytes};
 use ra_syntax::{ast, Parse, SyntaxNode};
 
 use crate::FileId;
+use rustc_hash::FxHashMap;
 
 fn syntax_tree_stats(db: &RootDatabase) -> SyntaxTreeStats {
     db.query(ra_db::ParseQuery).entries::<SyntaxTreeStats>()
@@ -123,20 +124,24 @@ struct LibrarySymbolsStats {
 
 impl fmt::Display for LibrarySymbolsStats {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        write!(fmt, "{} ({}) symbols", self.total, self.size,)
+        write!(fmt, "{} ({}) symbols", self.total, self.size)
     }
 }
 
-impl FromIterator<TableEntry<SourceRootId, Arc<SymbolIndex>>> for LibrarySymbolsStats {
+impl FromIterator<TableEntry<(), Arc<FxHashMap<SourceRootId, SymbolIndex>>>>
+    for LibrarySymbolsStats
+{
     fn from_iter<T>(iter: T) -> LibrarySymbolsStats
     where
-        T: IntoIterator<Item = TableEntry<SourceRootId, Arc<SymbolIndex>>>,
+        T: IntoIterator<Item = TableEntry<(), Arc<FxHashMap<SourceRootId, SymbolIndex>>>>,
     {
         let mut res = LibrarySymbolsStats::default();
         for entry in iter {
             let value = entry.value.unwrap();
-            res.total += value.len();
-            res.size += value.memory_size();
+            for symbols in value.values() {
+                res.total += symbols.len();
+                res.size += symbols.memory_size();
+            }
         }
         res
     }
diff --git a/crates/ra_ide/src/syntax_highlighting.rs b/crates/ra_ide/src/syntax_highlighting.rs
index 854b6cc6d..448645bdc 100644
--- a/crates/ra_ide/src/syntax_highlighting.rs
+++ b/crates/ra_ide/src/syntax_highlighting.rs
@@ -121,7 +121,6 @@ pub(crate) fn highlight(
                 assert!(current_macro_call == Some(mc));
                 current_macro_call = None;
                 format_string = None;
-                continue;
             }
             _ => (),
         }
@@ -150,7 +149,7 @@ pub(crate) fn highlight(
 
         let range = element.text_range();
 
-        let element_to_highlight = if current_macro_call.is_some() {
+        let element_to_highlight = if current_macro_call.is_some() && element.kind() != COMMENT {
             // Inside a macro -- expand it first
             let token = match element.clone().into_token() {
                 Some(it) if it.parent().kind() == TOKEN_TREE => it,
@@ -489,7 +488,14 @@ fn highlight_element(
         }
 
         // Simple token-based highlighting
-        COMMENT => HighlightTag::Comment.into(),
+        COMMENT => {
+            let comment = element.into_token().and_then(ast::Comment::cast)?;
+            let h = HighlightTag::Comment;
+            match comment.kind().doc {
+                Some(_) => h | HighlightModifier::Documentation,
+                None => h.into(),
+            }
+        }
         STRING | RAW_STRING | RAW_BYTE_STRING | BYTE_STRING => HighlightTag::StringLiteral.into(),
         ATTR => HighlightTag::Attribute.into(),
         INT_NUMBER | FLOAT_NUMBER => HighlightTag::NumericLiteral.into(),
diff --git a/crates/ra_ide/src/syntax_highlighting/injection.rs b/crates/ra_ide/src/syntax_highlighting/injection.rs
index 929a5cc5c..415f24a6d 100644
--- a/crates/ra_ide/src/syntax_highlighting/injection.rs
+++ b/crates/ra_ide/src/syntax_highlighting/injection.rs
@@ -7,7 +7,10 @@ use hir::Semantics;
 use ra_syntax::{ast, AstToken, SyntaxNode, SyntaxToken, TextRange, TextSize};
 use stdx::SepBy;
 
-use crate::{call_info::ActiveParameter, Analysis, HighlightTag, HighlightedRange, RootDatabase};
+use crate::{
+    call_info::ActiveParameter, Analysis, HighlightModifier, HighlightTag, HighlightedRange,
+    RootDatabase,
+};
 
 use super::HighlightedRangeStack;
 
@@ -118,7 +121,7 @@ pub(super) fn extract_doc_comments(
                     range.start(),
                     range.start() + TextSize::try_from(pos).unwrap(),
                 ),
-                highlight: HighlightTag::Comment.into(),
+                highlight: HighlightTag::Comment | HighlightModifier::Documentation,
                 binding_hash: None,
             });
             line_start += range.len() - TextSize::try_from(pos).unwrap();
@@ -164,6 +167,7 @@ pub(super) fn highlight_doc_comment(
                 h.range.start() + start_offset,
                 h.range.end() + end_offset.unwrap_or(start_offset),
             );
+
             stack.add(h);
         }
     }
diff --git a/crates/ra_ide/src/syntax_highlighting/tags.rs b/crates/ra_ide/src/syntax_highlighting/tags.rs
index 400d22fb6..93bbb4b4d 100644
--- a/crates/ra_ide/src/syntax_highlighting/tags.rs
+++ b/crates/ra_ide/src/syntax_highlighting/tags.rs
@@ -56,6 +56,7 @@ pub enum HighlightModifier {
     /// `foo` in `fn foo(x: i32)` is a definition, `foo` in `foo(90 + 2)` is
     /// not.
     Definition,
+    Documentation,
     Mutable,
     Unsafe,
 }
@@ -108,6 +109,7 @@ impl HighlightModifier {
         HighlightModifier::Attribute,
         HighlightModifier::ControlFlow,
         HighlightModifier::Definition,
+        HighlightModifier::Documentation,
         HighlightModifier::Mutable,
         HighlightModifier::Unsafe,
     ];
@@ -117,6 +119,7 @@ impl HighlightModifier {
             HighlightModifier::Attribute => "attribute",
             HighlightModifier::ControlFlow => "control",
             HighlightModifier::Definition => "declaration",
+            HighlightModifier::Documentation => "documentation",
             HighlightModifier::Mutable => "mutable",
             HighlightModifier::Unsafe => "unsafe",
         }
diff --git a/crates/ra_ide/src/syntax_highlighting/tests.rs b/crates/ra_ide/src/syntax_highlighting/tests.rs
index b4d56a7a0..93a276ffe 100644
--- a/crates/ra_ide/src/syntax_highlighting/tests.rs
+++ b/crates/ra_ide/src/syntax_highlighting/tests.rs
@@ -344,6 +344,15 @@ impl Foo {
         true
     }
 }
+
+/// ```
+/// noop!(1);
+/// ```
+macro_rules! noop {
+    ($expr:expr) => {
+        $expr
+    }
+}
 "#
         .trim(),
         "crates/ra_ide/src/snapshots/highlight_doctest.html",
diff --git a/crates/ra_ide_db/src/change.rs b/crates/ra_ide_db/src/change.rs
index 2fc796a85..98993d571 100644
--- a/crates/ra_ide_db/src/change.rs
+++ b/crates/ra_ide_db/src/change.rs
@@ -9,22 +9,15 @@ use ra_db::{
     SourceRootId,
 };
 use ra_prof::{memory_usage, profile, Bytes};
-use ra_syntax::SourceFile;
-#[cfg(not(feature = "wasm"))]
-use rayon::prelude::*;
 use rustc_hash::FxHashMap;
 
-use crate::{
-    symbol_index::{SymbolIndex, SymbolsDatabase},
-    RootDatabase,
-};
+use crate::{symbol_index::SymbolsDatabase, RootDatabase};
 
 #[derive(Default)]
 pub struct AnalysisChange {
     new_roots: Vec<(SourceRootId, bool)>,
     roots_changed: FxHashMap<SourceRootId, RootChange>,
     files_changed: Vec<(FileId, Arc<String>)>,
-    libraries_added: Vec<LibraryData>,
     crate_graph: Option<CrateGraph>,
 }
 
@@ -40,9 +33,6 @@ impl fmt::Debug for AnalysisChange {
         if !self.files_changed.is_empty() {
             d.field("files_changed", &self.files_changed.len());
         }
-        if !self.libraries_added.is_empty() {
-            d.field("libraries_added", &self.libraries_added.len());
-        }
         if self.crate_graph.is_some() {
             d.field("crate_graph", &self.crate_graph);
         }
@@ -79,10 +69,6 @@ impl AnalysisChange {
         self.roots_changed.entry(root_id).or_default().removed.push(file);
     }
 
-    pub fn add_library(&mut self, data: LibraryData) {
-        self.libraries_added.push(data)
-    }
-
     pub fn set_crate_graph(&mut self, graph: CrateGraph) {
         self.crate_graph = Some(graph);
     }
@@ -116,47 +102,6 @@ impl fmt::Debug for RootChange {
     }
 }
 
-pub struct LibraryData {
-    root_id: SourceRootId,
-    root_change: RootChange,
-    symbol_index: SymbolIndex,
-}
-
-impl fmt::Debug for LibraryData {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("LibraryData")
-            .field("root_id", &self.root_id)
-            .field("root_change", &self.root_change)
-            .field("n_symbols", &self.symbol_index.len())
-            .finish()
-    }
-}
-
-impl LibraryData {
-    pub fn prepare(
-        root_id: SourceRootId,
-        files: Vec<(FileId, RelativePathBuf, Arc<String>)>,
-    ) -> LibraryData {
-        let _p = profile("LibraryData::prepare");
-
-        #[cfg(not(feature = "wasm"))]
-        let iter = files.par_iter();
-        #[cfg(feature = "wasm")]
-        let iter = files.iter();
-
-        let symbol_index = SymbolIndex::for_files(iter.map(|(file_id, _, text)| {
-            let parse = SourceFile::parse(text);
-            (*file_id, parse)
-        }));
-        let mut root_change = RootChange::default();
-        root_change.added = files
-            .into_iter()
-            .map(|(file_id, path, text)| AddFile { file_id, path, text })
-            .collect();
-        LibraryData { root_id, root_change, symbol_index }
-    }
-}
-
 const GC_COOLDOWN: time::Duration = time::Duration::from_millis(100);
 
 impl RootDatabase {
@@ -171,6 +116,7 @@ impl RootDatabase {
         log::info!("apply_change {:?}", change);
         if !change.new_roots.is_empty() {
             let mut local_roots = Vec::clone(&self.local_roots());
+            let mut libraries = Vec::clone(&self.library_roots());
             for (root_id, is_local) in change.new_roots {
                 let root =
                     if is_local { SourceRoot::new_local() } else { SourceRoot::new_library() };
@@ -178,9 +124,12 @@ impl RootDatabase {
                 self.set_source_root_with_durability(root_id, Arc::new(root), durability);
                 if is_local {
                     local_roots.push(root_id);
+                } else {
+                    libraries.push(root_id)
                 }
             }
             self.set_local_roots_with_durability(Arc::new(local_roots), Durability::HIGH);
+            self.set_library_roots_with_durability(Arc::new(libraries), Durability::HIGH);
         }
 
         for (root_id, root_change) in change.roots_changed {
@@ -192,24 +141,6 @@ impl RootDatabase {
             let durability = durability(&source_root);
             self.set_file_text_with_durability(file_id, text, durability)
         }
-        if !change.libraries_added.is_empty() {
-            let mut libraries = Vec::clone(&self.library_roots());
-            for library in change.libraries_added {
-                libraries.push(library.root_id);
-                self.set_source_root_with_durability(
-                    library.root_id,
-                    Arc::new(SourceRoot::new_library()),
-                    Durability::HIGH,
-                );
-                self.set_library_symbols_with_durability(
-                    library.root_id,
-                    Arc::new(library.symbol_index),
-                    Durability::HIGH,
-                );
-                self.apply_root_change(library.root_id, library.root_change);
-            }
-            self.set_library_roots_with_durability(Arc::new(libraries), Durability::HIGH);
-        }
         if let Some(crate_graph) = change.crate_graph {
             self.set_crate_graph_with_durability(Arc::new(crate_graph), Durability::HIGH)
         }
@@ -352,7 +283,7 @@ impl RootDatabase {
             hir::db::GenericPredicatesQuery
             hir::db::GenericDefaultsQuery
             hir::db::ImplsInCrateQuery
-            hir::db::ImplsForTraitQuery
+            hir::db::ImplsFromDepsQuery
             hir::db::InternTypeCtorQuery
             hir::db::InternTypeParamIdQuery
             hir::db::InternChalkImplQuery
diff --git a/crates/ra_ide_db/src/symbol_index.rs b/crates/ra_ide_db/src/symbol_index.rs
index aab918973..25c99813f 100644
--- a/crates/ra_ide_db/src/symbol_index.rs
+++ b/crates/ra_ide_db/src/symbol_index.rs
@@ -34,14 +34,15 @@ use ra_db::{
     salsa::{self, ParallelDatabase},
     CrateId, FileId, SourceDatabaseExt, SourceRootId,
 };
+use ra_prof::profile;
 use ra_syntax::{
     ast::{self, NameOwner},
     match_ast, AstNode, Parse, SmolStr, SourceFile,
     SyntaxKind::{self, *},
     SyntaxNode, SyntaxNodePtr, TextRange, WalkEvent,
 };
-#[cfg(not(feature = "wasm"))]
 use rayon::prelude::*;
+use rustc_hash::FxHashMap;
 
 use crate::RootDatabase;
 
@@ -86,10 +87,9 @@ impl Query {
 }
 
 #[salsa::query_group(SymbolsDatabaseStorage)]
-pub trait SymbolsDatabase: hir::db::HirDatabase {
+pub trait SymbolsDatabase: hir::db::HirDatabase + SourceDatabaseExt + ParallelDatabase {
     fn file_symbols(&self, file_id: FileId) -> Arc<SymbolIndex>;
-    #[salsa::input]
-    fn library_symbols(&self, id: SourceRootId) -> Arc<SymbolIndex>;
+    fn library_symbols(&self) -> Arc<FxHashMap<SourceRootId, SymbolIndex>>;
     /// The set of "local" (that is, from the current workspace) roots.
     /// Files in local roots are assumed to change frequently.
     #[salsa::input]
@@ -100,6 +100,29 @@ pub trait SymbolsDatabase: hir::db::HirDatabase {
     fn library_roots(&self) -> Arc<Vec<SourceRootId>>;
 }
 
+fn library_symbols(
+    db: &(impl SymbolsDatabase + ParallelDatabase),
+) -> Arc<FxHashMap<SourceRootId, SymbolIndex>> {
+    let _p = profile("library_symbols");
+
+    let roots = db.library_roots();
+    let res = roots
+        .iter()
+        .map(|&root_id| {
+            let root = db.source_root(root_id);
+            let files = root
+                .walk()
+                .map(|it| (it, SourceDatabaseExt::file_text(db, it)))
+                .collect::<Vec<_>>();
+            let symbol_index = SymbolIndex::for_files(
+                files.into_par_iter().map(|(file, text)| (file, SourceFile::parse(&text))),
+            );
+            (root_id, symbol_index)
+        })
+        .collect();
+    Arc::new(res)
+}
+
 fn file_symbols(db: &impl SymbolsDatabase, file_id: FileId) -> Arc<SymbolIndex> {
     db.check_canceled();
     let parse = db.parse(file_id);
@@ -112,9 +135,9 @@ fn file_symbols(db: &impl SymbolsDatabase, file_id: FileId) -> Arc<SymbolIndex>
 }
 
 /// Need to wrap Snapshot to provide `Clone` impl for `map_with`
-struct Snap(salsa::Snapshot<RootDatabase>);
-impl Clone for Snap {
-    fn clone(&self) -> Snap {
+struct Snap<DB>(DB);
+impl<DB: ParallelDatabase> Clone for Snap<salsa::Snapshot<DB>> {
+    fn clone(&self) -> Snap<salsa::Snapshot<DB>> {
         Snap(self.0.snapshot())
     }
 }
@@ -143,19 +166,11 @@ impl Clone for Snap {
 pub fn world_symbols(db: &RootDatabase, query: Query) -> Vec<FileSymbol> {
     let _p = ra_prof::profile("world_symbols").detail(|| query.query.clone());
 
-    let buf: Vec<Arc<SymbolIndex>> = if query.libs {
-        let snap = Snap(db.snapshot());
-        #[cfg(not(feature = "wasm"))]
-        let buf = db
-            .library_roots()
-            .par_iter()
-            .map_with(snap, |db, &lib_id| db.0.library_symbols(lib_id))
-            .collect();
-
-        #[cfg(feature = "wasm")]
-        let buf = db.library_roots().iter().map(|&lib_id| snap.0.library_symbols(lib_id)).collect();
-
-        buf
+    let tmp1;
+    let tmp2;
+    let buf: Vec<&SymbolIndex> = if query.libs {
+        tmp1 = db.library_symbols();
+        tmp1.values().collect()
     } else {
         let mut files = Vec::new();
         for &root in db.local_roots().iter() {
@@ -164,14 +179,11 @@ pub fn world_symbols(db: &RootDatabase, query: Query) -> Vec<FileSymbol> {
         }
 
         let snap = Snap(db.snapshot());
-        #[cfg(not(feature = "wasm"))]
-        let buf =
-            files.par_iter().map_with(snap, |db, &file_id| db.0.file_symbols(file_id)).collect();
-
-        #[cfg(feature = "wasm")]
-        let buf = files.iter().map(|&file_id| snap.0.file_symbols(file_id)).collect();
-
-        buf
+        tmp2 = files
+            .par_iter()
+            .map_with(snap, |db, &file_id| db.0.file_symbols(file_id))
+            .collect::<Vec<_>>();
+        tmp2.iter().map(|it| &**it).collect()
     };
     query.search(&buf)
 }
@@ -191,14 +203,11 @@ pub fn crate_symbols(db: &RootDatabase, krate: CrateId, query: Query) -> Vec<Fil
 
     let snap = Snap(db.snapshot());
 
-    #[cfg(not(feature = "wasm"))]
     let buf = files
         .par_iter()
         .map_with(snap, |db, &file_id| db.0.file_symbols(file_id))
         .collect::<Vec<_>>();
-
-    #[cfg(feature = "wasm")]
-    let buf = files.iter().map(|&file_id| snap.0.file_symbols(file_id)).collect::<Vec<_>>();
+    let buf = buf.iter().map(|it| &**it).collect::<Vec<_>>();
 
     query.search(&buf)
 }
@@ -245,12 +254,8 @@ impl SymbolIndex {
             lhs_chars.cmp(rhs_chars)
         }
 
-        #[cfg(not(feature = "wasm"))]
         symbols.par_sort_by(cmp);
 
-        #[cfg(feature = "wasm")]
-        symbols.sort_by(cmp);
-
         let mut builder = fst::MapBuilder::memory();
 
         let mut last_batch_start = 0;
@@ -284,7 +289,6 @@ impl SymbolIndex {
         self.map.as_fst().size() + self.symbols.len() * mem::size_of::<FileSymbol>()
     }
 
-    #[cfg(not(feature = "wasm"))]
     pub(crate) fn for_files(
         files: impl ParallelIterator<Item = (FileId, Parse<ast::SourceFile>)>,
     ) -> SymbolIndex {
@@ -294,16 +298,6 @@ impl SymbolIndex {
         SymbolIndex::new(symbols)
     }
 
-    #[cfg(feature = "wasm")]
-    pub(crate) fn for_files(
-        files: impl Iterator<Item = (FileId, Parse<ast::SourceFile>)>,
-    ) -> SymbolIndex {
-        let symbols = files
-            .flat_map(|(file_id, file)| source_file_to_file_symbols(&file.tree(), file_id))
-            .collect::<Vec<_>>();
-        SymbolIndex::new(symbols)
-    }
-
     fn range_to_map_value(start: usize, end: usize) -> u64 {
         debug_assert![start <= (std::u32::MAX as usize)];
         debug_assert![end <= (std::u32::MAX as usize)];
@@ -319,7 +313,7 @@ impl SymbolIndex {
 }
 
 impl Query {
-    pub(crate) fn search(self, indices: &[Arc<SymbolIndex>]) -> Vec<FileSymbol> {
+    pub(crate) fn search(self, indices: &[&SymbolIndex]) -> Vec<FileSymbol> {
         let mut op = fst::map::OpBuilder::new();
         for file_symbols in indices.iter() {
             let automaton = fst::automaton::Subsequence::new(&self.lowercased);
diff --git a/crates/ra_proc_macro_srv/src/tests/fixtures/test_serialize_proc_macro.txt b/crates/ra_proc_macro_srv/src/tests/fixtures/test_serialize_proc_macro.txt
index bc010cfe9..e6fd21610 100644
--- a/crates/ra_proc_macro_srv/src/tests/fixtures/test_serialize_proc_macro.txt
+++ b/crates/ra_proc_macro_srv/src/tests/fixtures/test_serialize_proc_macro.txt
@@ -14,7 +14,7 @@ SUBTREE $
       PUNCH   , [alone] 4294967295
       IDENT   unused_qualifications 4294967295
   IDENT   const 4294967295
-  IDENT   _IMPL_SERIALIZE_FOR_Foo 4294967295
+  IDENT   _ 4294967295
   PUNCH   : [alone] 4294967295
   SUBTREE () 4294967295
   PUNCH   = [alone] 4294967295
diff --git a/crates/ra_syntax/src/ast/make.rs b/crates/ra_syntax/src/ast/make.rs
index da0eb0926..192c610f1 100644
--- a/crates/ra_syntax/src/ast/make.rs
+++ b/crates/ra_syntax/src/ast/make.rs
@@ -75,6 +75,10 @@ pub fn record_field(name: ast::NameRef, expr: Option<ast::Expr>) -> ast::RecordF
     }
 }
 
+pub fn record_field_def(name: ast::NameRef, ty: ast::TypeRef) -> ast::RecordFieldDef {
+    ast_from_text(&format!("struct S {{ {}: {}, }}", name, ty))
+}
+
 pub fn block_expr(
     stmts: impl IntoIterator<Item = ast::Stmt>,
     tail_expr: Option<ast::Expr>,
diff --git a/crates/ra_syntax/src/lib.rs b/crates/ra_syntax/src/lib.rs
index a33a35cc1..9b7664576 100644
--- a/crates/ra_syntax/src/lib.rs
+++ b/crates/ra_syntax/src/lib.rs
@@ -168,6 +168,41 @@ impl SourceFile {
     }
 }
 
+impl ast::Path {
+    /// Returns `text`, parsed as a path, but only if it has no errors.
+    pub fn parse(text: &str) -> Result<Self, ()> {
+        parsing::parse_text_fragment(text, ra_parser::FragmentKind::Path)
+    }
+}
+
+impl ast::Pat {
+    /// Returns `text`, parsed as a pattern, but only if it has no errors.
+    pub fn parse(text: &str) -> Result<Self, ()> {
+        parsing::parse_text_fragment(text, ra_parser::FragmentKind::Pattern)
+    }
+}
+
+impl ast::Expr {
+    /// Returns `text`, parsed as an expression, but only if it has no errors.
+    pub fn parse(text: &str) -> Result<Self, ()> {
+        parsing::parse_text_fragment(text, ra_parser::FragmentKind::Expr)
+    }
+}
+
+impl ast::ModuleItem {
+    /// Returns `text`, parsed as an item, but only if it has no errors.
+    pub fn parse(text: &str) -> Result<Self, ()> {
+        parsing::parse_text_fragment(text, ra_parser::FragmentKind::Item)
+    }
+}
+
+impl ast::TypeRef {
+    /// Returns `text`, parsed as an type reference, but only if it has no errors.
+    pub fn parse(text: &str) -> Result<Self, ()> {
+        parsing::parse_text_fragment(text, ra_parser::FragmentKind::Type)
+    }
+}
+
 /// Matches a `SyntaxNode` against an `ast` type.
 ///
 /// # Example:
diff --git a/crates/ra_syntax/src/parsing.rs b/crates/ra_syntax/src/parsing.rs
index e5eb80850..0ed3c20ef 100644
--- a/crates/ra_syntax/src/parsing.rs
+++ b/crates/ra_syntax/src/parsing.rs
@@ -6,13 +6,14 @@ mod text_token_source;
 mod text_tree_sink;
 mod reparsing;
 
-use crate::{syntax_node::GreenNode, SyntaxError};
+use crate::{syntax_node::GreenNode, AstNode, SyntaxError, SyntaxNode};
 use text_token_source::TextTokenSource;
 use text_tree_sink::TextTreeSink;
 
 pub use lexer::*;
 
 pub(crate) use self::reparsing::incremental_reparse;
+use ra_parser::SyntaxKind;
 
 pub(crate) fn parse_text(text: &str) -> (GreenNode, Vec<SyntaxError>) {
     let (tokens, lexer_errors) = tokenize(&text);
@@ -27,3 +28,32 @@ pub(crate) fn parse_text(text: &str) -> (GreenNode, Vec<SyntaxError>) {
 
     (tree, parser_errors)
 }
+
+/// Returns `text` parsed as a `T` provided there are no parse errors.
+pub(crate) fn parse_text_fragment<T: AstNode>(
+    text: &str,
+    fragment_kind: ra_parser::FragmentKind,
+) -> Result<T, ()> {
+    let (tokens, lexer_errors) = tokenize(&text);
+    if !lexer_errors.is_empty() {
+        return Err(());
+    }
+
+    let mut token_source = TextTokenSource::new(text, &tokens);
+    let mut tree_sink = TextTreeSink::new(text, &tokens);
+
+    // TextTreeSink assumes that there's at least some root node to which it can attach errors and
+    // tokens. We arbitrarily give it a SourceFile.
+    use ra_parser::TreeSink;
+    tree_sink.start_node(SyntaxKind::SOURCE_FILE);
+    ra_parser::parse_fragment(&mut token_source, &mut tree_sink, fragment_kind);
+    tree_sink.finish_node();
+
+    let (tree, parser_errors) = tree_sink.finish();
+    use ra_parser::TokenSource;
+    if !parser_errors.is_empty() || token_source.current().kind != SyntaxKind::EOF {
+        return Err(());
+    }
+
+    SyntaxNode::new_root(tree).first_child().and_then(T::cast).ok_or(())
+}
diff --git a/crates/ra_syntax/src/parsing/text_token_source.rs b/crates/ra_syntax/src/parsing/text_token_source.rs
index 7ddc2c2c3..97aa3e795 100644
--- a/crates/ra_syntax/src/parsing/text_token_source.rs
+++ b/crates/ra_syntax/src/parsing/text_token_source.rs
@@ -1,40 +1,35 @@
-//! FIXME: write short doc here
+//! See `TextTokenSource` docs.
 
-use ra_parser::Token as PToken;
 use ra_parser::TokenSource;
 
 use crate::{parsing::lexer::Token, SyntaxKind::EOF, TextRange, TextSize};
 
+/// Implementation of `ra_parser::TokenSource` that takes tokens from source code text.
 pub(crate) struct TextTokenSource<'t> {
     text: &'t str,
-    /// start position of each token(expect whitespace and comment)
+    /// token and its start position (non-whitespace/comment tokens)
     /// ```non-rust
     ///  struct Foo;
-    /// ^------^---
-    /// |      |  ^-
-    /// 0      7  10
+    ///  ^------^--^-
+    ///  |      |    \________
+    ///  |      \____         \
+    ///  |           \         |
+    ///  (struct, 0) (Foo, 7) (;, 10)
     /// ```
-    /// (token, start_offset): `[(struct, 0), (Foo, 7), (;, 10)]`
-    start_offsets: Vec<TextSize>,
-    /// non-whitespace/comment tokens
-    /// ```non-rust
-    /// struct Foo {}
-    /// ^^^^^^ ^^^ ^^
-    /// ```
-    /// tokens: `[struct, Foo, {, }]`
-    tokens: Vec<Token>,
+    /// `[(struct, 0), (Foo, 7), (;, 10)]`
+    token_offset_pairs: Vec<(Token, TextSize)>,
 
     /// Current token and position
-    curr: (PToken, usize),
+    curr: (ra_parser::Token, usize),
 }
 
 impl<'t> TokenSource for TextTokenSource<'t> {
-    fn current(&self) -> PToken {
+    fn current(&self) -> ra_parser::Token {
         self.curr.0
     }
 
-    fn lookahead_nth(&self, n: usize) -> PToken {
-        mk_token(self.curr.1 + n, &self.start_offsets, &self.tokens)
+    fn lookahead_nth(&self, n: usize) -> ra_parser::Token {
+        mk_token(self.curr.1 + n, &self.token_offset_pairs)
     }
 
     fn bump(&mut self) {
@@ -43,45 +38,47 @@ impl<'t> TokenSource for TextTokenSource<'t> {
         }
 
         let pos = self.curr.1 + 1;
-        self.curr = (mk_token(pos, &self.start_offsets, &self.tokens), pos);
+        self.curr = (mk_token(pos, &self.token_offset_pairs), pos);
     }
 
     fn is_keyword(&self, kw: &str) -> bool {
-        let pos = self.curr.1;
-        if pos >= self.tokens.len() {
-            return false;
-        }
-        let range = TextRange::at(self.start_offsets[pos], self.tokens[pos].len);
-        self.text[range] == *kw
+        self.token_offset_pairs
+            .get(self.curr.1)
+            .map(|(token, offset)| &self.text[TextRange::at(*offset, token.len)] == kw)
+            .unwrap_or(false)
     }
 }
 
-fn mk_token(pos: usize, start_offsets: &[TextSize], tokens: &[Token]) -> PToken {
-    let kind = tokens.get(pos).map(|t| t.kind).unwrap_or(EOF);
-    let is_jointed_to_next = if pos + 1 < start_offsets.len() {
-        start_offsets[pos] + tokens[pos].len == start_offsets[pos + 1]
-    } else {
-        false
+fn mk_token(pos: usize, token_offset_pairs: &[(Token, TextSize)]) -> ra_parser::Token {
+    let (kind, is_jointed_to_next) = match token_offset_pairs.get(pos) {
+        Some((token, offset)) => (
+            token.kind,
+            token_offset_pairs
+                .get(pos + 1)
+                .map(|(_, next_offset)| offset + token.len == *next_offset)
+                .unwrap_or(false),
+        ),
+        None => (EOF, false),
     };
-
-    PToken { kind, is_jointed_to_next }
+    ra_parser::Token { kind, is_jointed_to_next }
 }
 
 impl<'t> TextTokenSource<'t> {
     /// Generate input from tokens(expect comment and whitespace).
     pub fn new(text: &'t str, raw_tokens: &'t [Token]) -> TextTokenSource<'t> {
-        let mut tokens = Vec::new();
-        let mut start_offsets = Vec::new();
-        let mut len = 0.into();
-        for &token in raw_tokens.iter() {
-            if !token.kind.is_trivia() {
-                tokens.push(token);
-                start_offsets.push(len);
-            }
-            len += token.len;
-        }
+        let token_offset_pairs: Vec<_> = raw_tokens
+            .iter()
+            .filter_map({
+                let mut len = 0.into();
+                move |token| {
+                    let pair = if token.kind.is_trivia() { None } else { Some((*token, len)) };
+                    len += token.len;
+                    pair
+                }
+            })
+            .collect();
 
-        let first = mk_token(0, &start_offsets, &tokens);
-        TextTokenSource { text, start_offsets, tokens, curr: (first, 0) }
+        let first = mk_token(0, &token_offset_pairs);
+        TextTokenSource { text, token_offset_pairs, curr: (first, 0) }
     }
 }
diff --git a/crates/ra_syntax/src/tests.rs b/crates/ra_syntax/src/tests.rs
index aee57db62..959967b79 100644
--- a/crates/ra_syntax/src/tests.rs
+++ b/crates/ra_syntax/src/tests.rs
@@ -55,6 +55,51 @@ fn parser_tests() {
 }
 
 #[test]
+fn expr_parser_tests() {
+    fragment_parser_dir_test(
+        &["parser/fragments/expr/ok"],
+        &["parser/fragments/expr/err"],
+        crate::ast::Expr::parse,
+    );
+}
+
+#[test]
+fn path_parser_tests() {
+    fragment_parser_dir_test(
+        &["parser/fragments/path/ok"],
+        &["parser/fragments/path/err"],
+        crate::ast::Path::parse,
+    );
+}
+
+#[test]
+fn pattern_parser_tests() {
+    fragment_parser_dir_test(
+        &["parser/fragments/pattern/ok"],
+        &["parser/fragments/pattern/err"],
+        crate::ast::Pat::parse,
+    );
+}
+
+#[test]
+fn item_parser_tests() {
+    fragment_parser_dir_test(
+        &["parser/fragments/item/ok"],
+        &["parser/fragments/item/err"],
+        crate::ast::ModuleItem::parse,
+    );
+}
+
+#[test]
+fn type_parser_tests() {
+    fragment_parser_dir_test(
+        &["parser/fragments/type/ok"],
+        &["parser/fragments/type/err"],
+        crate::ast::TypeRef::parse,
+    );
+}
+
+#[test]
 fn parser_fuzz_tests() {
     for (_, text) in collect_rust_files(&test_data_dir(), &["parser/fuzz-failures"]) {
         fuzz::check_parser(&text)
@@ -134,3 +179,24 @@ fn dump_tokens_and_errors(tokens: &[Token], errors: &[SyntaxError], text: &str)
     }
     acc
 }
+
+fn fragment_parser_dir_test<T, F>(ok_paths: &[&str], err_paths: &[&str], f: F)
+where
+    T: crate::AstNode,
+    F: Fn(&str) -> Result<T, ()>,
+{
+    dir_tests(&test_data_dir(), ok_paths, "rast", |text, path| {
+        if let Ok(node) = f(text) {
+            format!("{:#?}", crate::ast::AstNode::syntax(&node))
+        } else {
+            panic!("Failed to parse '{:?}'", path);
+        }
+    });
+    dir_tests(&test_data_dir(), err_paths, "rast", |text, path| {
+        if let Ok(_) = f(text) {
+            panic!("'{:?}' successfully parsed when it should have errored", path);
+        } else {
+            "ERROR\n".to_owned()
+        }
+    });
+}
diff --git a/crates/ra_syntax/test_data/parser/fragments/expr/err/0000_truncated_add.rast b/crates/ra_syntax/test_data/parser/fragments/expr/err/0000_truncated_add.rast
new file mode 100644
index 000000000..5df7507e2
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/expr/err/0000_truncated_add.rast
@@ -0,0 +1 @@
+ERROR
diff --git a/crates/ra_syntax/test_data/parser/fragments/expr/err/0000_truncated_add.rs b/crates/ra_syntax/test_data/parser/fragments/expr/err/0000_truncated_add.rs
new file mode 100644
index 000000000..ca49acb07
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/expr/err/0000_truncated_add.rs
@@ -0,0 +1 @@
+1 +
diff --git a/crates/ra_syntax/test_data/parser/fragments/expr/ok/0000_add.rast b/crates/ra_syntax/test_data/parser/fragments/expr/ok/0000_add.rast
new file mode 100644
index 000000000..fa78a02a6
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/expr/ok/0000_add.rast
@@ -0,0 +1,8 @@
+[email protected]
+  [email protected]
+    [email protected] "1"
+  [email protected] " "
+  [email protected] "+"
+  [email protected] " "
+  [email protected]
+    [email protected] "2"
diff --git a/crates/ra_syntax/test_data/parser/fragments/expr/ok/0000_add.rs b/crates/ra_syntax/test_data/parser/fragments/expr/ok/0000_add.rs
new file mode 100644
index 000000000..e0ef58402
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/expr/ok/0000_add.rs
@@ -0,0 +1 @@
+1 + 2
diff --git a/crates/ra_syntax/test_data/parser/fragments/item/err/0000_extra_keyword.rast b/crates/ra_syntax/test_data/parser/fragments/item/err/0000_extra_keyword.rast
new file mode 100644
index 000000000..5df7507e2
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/item/err/0000_extra_keyword.rast
@@ -0,0 +1 @@
+ERROR
diff --git a/crates/ra_syntax/test_data/parser/fragments/item/err/0000_extra_keyword.rs b/crates/ra_syntax/test_data/parser/fragments/item/err/0000_extra_keyword.rs
new file mode 100644
index 000000000..dc32389bb
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/item/err/0000_extra_keyword.rs
@@ -0,0 +1 @@
+fn fn foo() {}
diff --git a/crates/ra_syntax/test_data/parser/fragments/item/ok/0000_fn.rast b/crates/ra_syntax/test_data/parser/fragments/item/ok/0000_fn.rast
new file mode 100644
index 000000000..f1e78f388
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/item/ok/0000_fn.rast
@@ -0,0 +1,12 @@
+[email protected]
+  [email protected] "fn"
+  [email protected] " "
+  [email protected]
+    [email protected] "foo"
+  [email protected]
+    [email protected] "("
+    [email protected] ")"
+  [email protected] " "
+  [email protected]
+    [email protected] "{"
+    [email protected] "}"
diff --git a/crates/ra_syntax/test_data/parser/fragments/item/ok/0000_fn.rs b/crates/ra_syntax/test_data/parser/fragments/item/ok/0000_fn.rs
new file mode 100644
index 000000000..8f3b7ef11
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/item/ok/0000_fn.rs
@@ -0,0 +1 @@
+fn foo() {}
diff --git a/crates/ra_syntax/test_data/parser/fragments/path/err/0000_reserved_word.rast b/crates/ra_syntax/test_data/parser/fragments/path/err/0000_reserved_word.rast
new file mode 100644
index 000000000..5df7507e2
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/path/err/0000_reserved_word.rast
@@ -0,0 +1 @@
+ERROR
diff --git a/crates/ra_syntax/test_data/parser/fragments/path/err/0000_reserved_word.rs b/crates/ra_syntax/test_data/parser/fragments/path/err/0000_reserved_word.rs
new file mode 100644
index 000000000..2046de049
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/path/err/0000_reserved_word.rs
@@ -0,0 +1 @@
+struct
diff --git a/crates/ra_syntax/test_data/parser/fragments/path/err/0001_expression.rast b/crates/ra_syntax/test_data/parser/fragments/path/err/0001_expression.rast
new file mode 100644
index 000000000..5df7507e2
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/path/err/0001_expression.rast
@@ -0,0 +1 @@
+ERROR
diff --git a/crates/ra_syntax/test_data/parser/fragments/path/err/0001_expression.rs b/crates/ra_syntax/test_data/parser/fragments/path/err/0001_expression.rs
new file mode 100644
index 000000000..745e8d376
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/path/err/0001_expression.rs
@@ -0,0 +1 @@
+a + b
diff --git a/crates/ra_syntax/test_data/parser/fragments/path/ok/0000_single_ident.rast b/crates/ra_syntax/test_data/parser/fragments/path/ok/0000_single_ident.rast
new file mode 100644
index 000000000..0c5d4360f
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/path/ok/0000_single_ident.rast
@@ -0,0 +1,4 @@
+[email protected]
+  [email protected]
+    [email protected]
+      [email protected] "foo"
diff --git a/crates/ra_syntax/test_data/parser/fragments/path/ok/0000_single_ident.rs b/crates/ra_syntax/test_data/parser/fragments/path/ok/0000_single_ident.rs
new file mode 100644
index 000000000..257cc5642
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/path/ok/0000_single_ident.rs
@@ -0,0 +1 @@
+foo
diff --git a/crates/ra_syntax/test_data/parser/fragments/path/ok/0001_multipart.rast b/crates/ra_syntax/test_data/parser/fragments/path/ok/0001_multipart.rast
new file mode 100644
index 000000000..4a2b45e6a
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/path/ok/0001_multipart.rast
@@ -0,0 +1,14 @@
+[email protected]
+  [email protected]
+    [email protected]
+      [email protected]
+        [email protected]
+          [email protected] "foo"
+    [email protected] "::"
+    [email protected]
+      [email protected]
+        [email protected] "bar"
+  [email protected] "::"
+  [email protected]
+    [email protected]
+      [email protected] "baz"
diff --git a/crates/ra_syntax/test_data/parser/fragments/path/ok/0001_multipart.rs b/crates/ra_syntax/test_data/parser/fragments/path/ok/0001_multipart.rs
new file mode 100644
index 000000000..81e0b21cd
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/path/ok/0001_multipart.rs
@@ -0,0 +1 @@
+foo::bar::baz
diff --git a/crates/ra_syntax/test_data/parser/fragments/pattern/err/0000_reserved_word.rast b/crates/ra_syntax/test_data/parser/fragments/pattern/err/0000_reserved_word.rast
new file mode 100644
index 000000000..5df7507e2
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/pattern/err/0000_reserved_word.rast
@@ -0,0 +1 @@
+ERROR
diff --git a/crates/ra_syntax/test_data/parser/fragments/pattern/err/0000_reserved_word.rs b/crates/ra_syntax/test_data/parser/fragments/pattern/err/0000_reserved_word.rs
new file mode 100644
index 000000000..ae26fc455
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/pattern/err/0000_reserved_word.rs
@@ -0,0 +1 @@
+fn
diff --git a/crates/ra_syntax/test_data/parser/fragments/pattern/err/0001_missing_paren.rast b/crates/ra_syntax/test_data/parser/fragments/pattern/err/0001_missing_paren.rast
new file mode 100644
index 000000000..5df7507e2
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/pattern/err/0001_missing_paren.rast
@@ -0,0 +1 @@
+ERROR
diff --git a/crates/ra_syntax/test_data/parser/fragments/pattern/err/0001_missing_paren.rs b/crates/ra_syntax/test_data/parser/fragments/pattern/err/0001_missing_paren.rs
new file mode 100644
index 000000000..61a391d08
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/pattern/err/0001_missing_paren.rs
@@ -0,0 +1 @@
+Some(x
diff --git a/crates/ra_syntax/test_data/parser/fragments/pattern/ok/0000_enum.rast b/crates/ra_syntax/test_data/parser/fragments/pattern/ok/0000_enum.rast
new file mode 100644
index 000000000..15eb7f9c6
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/pattern/ok/0000_enum.rast
@@ -0,0 +1,10 @@
+[email protected]
+  [email protected]
+    [email protected]
+      [email protected]
+        [email protected] "Some"
+  [email protected] "("
+  [email protected]
+    [email protected]
+      [email protected] "x"
+  [email protected] ")"
diff --git a/crates/ra_syntax/test_data/parser/fragments/pattern/ok/0000_enum.rs b/crates/ra_syntax/test_data/parser/fragments/pattern/ok/0000_enum.rs
new file mode 100644
index 000000000..87114dd78
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/pattern/ok/0000_enum.rs
@@ -0,0 +1 @@
+Some(x)
diff --git a/crates/ra_syntax/test_data/parser/fragments/type/err/0000_missing_close.rast b/crates/ra_syntax/test_data/parser/fragments/type/err/0000_missing_close.rast
new file mode 100644
index 000000000..5df7507e2
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/type/err/0000_missing_close.rast
@@ -0,0 +1 @@
+ERROR
diff --git a/crates/ra_syntax/test_data/parser/fragments/type/err/0000_missing_close.rs b/crates/ra_syntax/test_data/parser/fragments/type/err/0000_missing_close.rs
new file mode 100644
index 000000000..caa4d7c09
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/type/err/0000_missing_close.rs
@@ -0,0 +1 @@
+Result<Foo, Bar
diff --git a/crates/ra_syntax/test_data/parser/fragments/type/ok/0000_result.rast b/crates/ra_syntax/test_data/parser/fragments/type/ok/0000_result.rast
new file mode 100644
index 000000000..8831cfa6c
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/type/ok/0000_result.rast
@@ -0,0 +1,22 @@
+[email protected]
+  [email protected]
+    [email protected]
+      [email protected]
+        [email protected] "Result"
+      [email protected]
+        [email protected] "<"
+        [email protected]
+          [email protected]
+            [email protected]
+              [email protected]
+                [email protected]
+                  [email protected] "Foo"
+        [email protected] ","
+        [email protected] " "
+        [email protected]
+          [email protected]
+            [email protected]
+              [email protected]
+                [email protected]
+                  [email protected] "Bar"
+        [email protected] ">"
diff --git a/crates/ra_syntax/test_data/parser/fragments/type/ok/0000_result.rs b/crates/ra_syntax/test_data/parser/fragments/type/ok/0000_result.rs
new file mode 100644
index 000000000..b50b3bb3b
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/fragments/type/ok/0000_result.rs
@@ -0,0 +1 @@
+Result<Foo, Bar>
diff --git a/crates/rust-analyzer/Cargo.toml b/crates/rust-analyzer/Cargo.toml
index 458089e53..2b46e8905 100644
--- a/crates/rust-analyzer/Cargo.toml
+++ b/crates/rust-analyzer/Cargo.toml
@@ -32,7 +32,7 @@ threadpool = "1.7.1"
 
 stdx = { path = "../stdx" }
 
-lsp-server = "0.3.2"
+lsp-server = "0.3.3"
 ra_flycheck = { path = "../ra_flycheck" }
 ra_ide = { path = "../ra_ide" }
 ra_prof = { path = "../ra_prof" }
diff --git a/crates/rust-analyzer/build.rs b/crates/rust-analyzer/build.rs
index d4b010c04..5ae76ba30 100644
--- a/crates/rust-analyzer/build.rs
+++ b/crates/rust-analyzer/build.rs
@@ -5,11 +5,14 @@ use std::{env, path::PathBuf, process::Command};
 fn main() {
     set_rerun();
 
-    let rev = rev().unwrap_or_else(|| "???????".to_string());
+    let rev =
+        env::var("RUST_ANALYZER_REV").ok().or_else(rev).unwrap_or_else(|| "???????".to_string());
     println!("cargo:rustc-env=REV={}", rev)
 }
 
 fn set_rerun() {
+    println!("cargo:rerun-if-env-changed=RUST_ANALYZER_REV");
+
     let mut manifest_dir = PathBuf::from(
         env::var("CARGO_MANIFEST_DIR").expect("`CARGO_MANIFEST_DIR` is always set by cargo."),
     );
diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs
index 0df7427cb..aa2c4ae15 100644
--- a/crates/rust-analyzer/src/config.rs
+++ b/crates/rust-analyzer/src/config.rs
@@ -296,6 +296,7 @@ impl Config {
             set(value, "/hoverActions/implementations", &mut self.hover.implementations);
             set(value, "/hoverActions/run", &mut self.hover.run);
             set(value, "/hoverActions/debug", &mut self.hover.debug);
+            set(value, "/hoverActions/gotoTypeDef", &mut self.hover.goto_type_def);
         } else {
             self.hover = HoverConfig::NO_ACTIONS;
         }
diff --git a/crates/rust-analyzer/src/global_state.rs b/crates/rust-analyzer/src/global_state.rs
index ef6c7d44d..d04ef4c61 100644
--- a/crates/rust-analyzer/src/global_state.rs
+++ b/crates/rust-analyzer/src/global_state.rs
@@ -12,18 +12,15 @@ use crossbeam_channel::{unbounded, Receiver};
 use lsp_types::Url;
 use parking_lot::RwLock;
 use ra_flycheck::{Flycheck, FlycheckConfig};
-use ra_ide::{
-    Analysis, AnalysisChange, AnalysisHost, CrateGraph, FileId, LibraryData, SourceRootId,
-};
+use ra_ide::{Analysis, AnalysisChange, AnalysisHost, CrateGraph, FileId, SourceRootId};
 use ra_project_model::{CargoWorkspace, ProcMacroClient, ProjectWorkspace, Target};
 use ra_vfs::{LineEndings, RootEntry, Vfs, VfsChange, VfsFile, VfsTask, Watch};
-use relative_path::RelativePathBuf;
 use stdx::format_to;
 
 use crate::{
-    config::Config,
+    config::{Config, FilesWatcher},
     diagnostics::{CheckFixes, DiagnosticCollection},
-    main_loop::pending_requests::{CompletedRequest, LatestRequests},
+    main_loop::request_metrics::{LatestRequests, RequestMetrics},
     to_proto::url_from_abs_path,
     vfs_glob::{Glob, RustPackageFilterBuilder},
     LspError, Result,
@@ -33,20 +30,16 @@ use rustc_hash::{FxHashMap, FxHashSet};
 
 fn create_flycheck(workspaces: &[ProjectWorkspace], config: &FlycheckConfig) -> Option<Flycheck> {
     // FIXME: Figure out the multi-workspace situation
-    workspaces
-        .iter()
-        .find_map(|w| match w {
-            ProjectWorkspace::Cargo { cargo, .. } => Some(cargo),
-            ProjectWorkspace::Json { .. } => None,
-        })
-        .map(|cargo| {
+    workspaces.iter().find_map(|w| match w {
+        ProjectWorkspace::Cargo { cargo, .. } => {
             let cargo_project_root = cargo.workspace_root().to_path_buf();
             Some(Flycheck::new(config.clone(), cargo_project_root))
-        })
-        .unwrap_or_else(|| {
+        }
+        ProjectWorkspace::Json { .. } => {
             log::warn!("Cargo check watching only supported for cargo workspaces, disabling");
             None
-        })
+        }
+    })
 }
 
 /// `GlobalState` is the primary mutable state of the language server
@@ -62,10 +55,10 @@ pub struct GlobalState {
     pub analysis_host: AnalysisHost,
     pub vfs: Arc<RwLock<Vfs>>,
     pub task_receiver: Receiver<VfsTask>,
-    pub latest_requests: Arc<RwLock<LatestRequests>>,
     pub flycheck: Option<Flycheck>,
     pub diagnostics: DiagnosticCollection,
     pub proc_macro_client: ProcMacroClient,
+    pub(crate) latest_requests: Arc<RwLock<LatestRequests>>,
 }
 
 /// An immutable snapshot of the world's state at a point in time.
@@ -73,8 +66,8 @@ pub struct GlobalStateSnapshot {
     pub config: Config,
     pub workspaces: Arc<Vec<ProjectWorkspace>>,
     pub analysis: Analysis,
-    pub latest_requests: Arc<RwLock<LatestRequests>>,
     pub check_fixes: CheckFixes,
+    pub(crate) latest_requests: Arc<RwLock<LatestRequests>>,
     vfs: Arc<RwLock<Vfs>>,
 }
 
@@ -83,7 +76,6 @@ impl GlobalState {
         workspaces: Vec<ProjectWorkspace>,
         lru_capacity: Option<usize>,
         exclude_globs: &[Glob],
-        watch: Watch,
         config: Config,
     ) -> GlobalState {
         let mut change = AnalysisChange::new();
@@ -118,6 +110,7 @@ impl GlobalState {
 
         let (task_sender, task_receiver) = unbounded();
         let task_sender = Box::new(move |t| task_sender.send(t).unwrap());
+        let watch = Watch(matches!(config.files.watcher, FilesWatcher::Notify));
         let (mut vfs, vfs_roots) = Vfs::new(roots, task_sender, watch);
 
         let mut extern_source_roots = FxHashMap::default();
@@ -195,32 +188,18 @@ impl GlobalState {
 
     /// Returns a vec of libraries
     /// FIXME: better API here
-    pub fn process_changes(
-        &mut self,
-        roots_scanned: &mut usize,
-    ) -> Option<Vec<(SourceRootId, Vec<(FileId, RelativePathBuf, Arc<String>)>)>> {
+    pub fn process_changes(&mut self, roots_scanned: &mut usize) -> bool {
         let changes = self.vfs.write().commit_changes();
         if changes.is_empty() {
-            return None;
+            return false;
         }
-        let mut libs = Vec::new();
         let mut change = AnalysisChange::new();
         for c in changes {
             match c {
                 VfsChange::AddRoot { root, files } => {
-                    let root_path = self.vfs.read().root2path(root);
-                    let is_local = self.local_roots.iter().any(|r| root_path.starts_with(r));
-                    if is_local {
-                        *roots_scanned += 1;
-                        for (file, path, text) in files {
-                            change.add_file(SourceRootId(root.0), FileId(file.0), path, text);
-                        }
-                    } else {
-                        let files = files
-                            .into_iter()
-                            .map(|(vfsfile, path, text)| (FileId(vfsfile.0), path, text))
-                            .collect();
-                        libs.push((SourceRootId(root.0), files));
+                    *roots_scanned += 1;
+                    for (file, path, text) in files {
+                        change.add_file(SourceRootId(root.0), FileId(file.0), path, text);
                     }
                 }
                 VfsChange::AddFile { root, file, path, text } => {
@@ -235,13 +214,7 @@ impl GlobalState {
             }
         }
         self.analysis_host.apply_change(change);
-        Some(libs)
-    }
-
-    pub fn add_lib(&mut self, data: LibraryData) {
-        let mut change = AnalysisChange::new();
-        change.add_library(data);
-        self.analysis_host.apply_change(change);
+        true
     }
 
     pub fn snapshot(&self) -> GlobalStateSnapshot {
@@ -263,7 +236,7 @@ impl GlobalState {
         self.analysis_host.collect_garbage()
     }
 
-    pub fn complete_request(&mut self, request: CompletedRequest) {
+    pub(crate) fn complete_request(&mut self, request: RequestMetrics) {
         self.latest_requests.write().record(request)
     }
 }
diff --git a/crates/rust-analyzer/src/lib.rs b/crates/rust-analyzer/src/lib.rs
index 609cb69d3..64e70955f 100644
--- a/crates/rust-analyzer/src/lib.rs
+++ b/crates/rust-analyzer/src/lib.rs
@@ -32,7 +32,7 @@ mod semantic_tokens;
 
 use serde::de::DeserializeOwned;
 
-pub type Result<T> = std::result::Result<T, Box<dyn std::error::Error + Send + Sync>>;
+pub type Result<T, E = Box<dyn std::error::Error + Send + Sync>> = std::result::Result<T, E>;
 pub use crate::{
     caps::server_capabilities,
     main_loop::LspError,
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index 80cfd3c28..674b1323b 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -3,7 +3,7 @@
 
 mod handlers;
 mod subscriptions;
-pub(crate) mod pending_requests;
+pub(crate) mod request_metrics;
 
 use std::{
     borrow::Cow,
@@ -17,19 +17,19 @@ use std::{
 };
 
 use crossbeam_channel::{never, select, unbounded, RecvError, Sender};
-use lsp_server::{Connection, ErrorCode, Message, Notification, Request, RequestId, Response};
+use lsp_server::{
+    Connection, ErrorCode, Message, Notification, ReqQueue, Request, RequestId, Response,
+};
 use lsp_types::{
-    DidChangeTextDocumentParams, NumberOrString, TextDocumentContentChangeEvent, WorkDoneProgress,
-    WorkDoneProgressBegin, WorkDoneProgressCreateParams, WorkDoneProgressEnd,
-    WorkDoneProgressReport,
+    request::Request as _, DidChangeTextDocumentParams, NumberOrString,
+    TextDocumentContentChangeEvent, WorkDoneProgress, WorkDoneProgressBegin,
+    WorkDoneProgressCreateParams, WorkDoneProgressEnd, WorkDoneProgressReport,
 };
 use ra_flycheck::{CheckTask, Status};
-use ra_ide::{Canceled, FileId, LibraryData, LineIndex, SourceRootId};
+use ra_ide::{Canceled, FileId, LineIndex};
 use ra_prof::profile;
 use ra_project_model::{PackageRoot, ProjectWorkspace};
-use ra_vfs::{VfsTask, Watch};
-use relative_path::RelativePathBuf;
-use rustc_hash::FxHashSet;
+use ra_vfs::VfsTask;
 use serde::{de::DeserializeOwned, Serialize};
 use threadpool::ThreadPool;
 
@@ -39,10 +39,7 @@ use crate::{
     from_proto,
     global_state::{file_id_to_url, GlobalState, GlobalStateSnapshot},
     lsp_ext,
-    main_loop::{
-        pending_requests::{PendingRequest, PendingRequests},
-        subscriptions::Subscriptions,
-    },
+    main_loop::{request_metrics::RequestMetrics, subscriptions::Subscriptions},
     Result,
 };
 
@@ -154,32 +151,25 @@ pub fn main_loop(config: Config, connection: Connection) -> Result<()> {
                 register_options: Some(serde_json::to_value(registration_options).unwrap()),
             };
             let params = lsp_types::RegistrationParams { registrations: vec![registration] };
-            let request = request_new::<lsp_types::request::RegisterCapability>(
-                loop_state.next_request_id(),
+            let request = loop_state.req_queue.outgoing.register(
+                lsp_types::request::RegisterCapability::METHOD.to_string(),
                 params,
+                DO_NOTHING,
             );
             connection.sender.send(request.into()).unwrap();
         }
 
-        GlobalState::new(
-            workspaces,
-            config.lru_capacity,
-            &globs,
-            Watch(matches!(config.files.watcher, FilesWatcher::Notify)),
-            config,
-        )
+        GlobalState::new(workspaces, config.lru_capacity, &globs, config)
     };
 
     loop_state.roots_total = global_state.vfs.read().n_roots();
 
     let pool = ThreadPool::default();
     let (task_sender, task_receiver) = unbounded::<Task>();
-    let (libdata_sender, libdata_receiver) = unbounded::<LibraryData>();
 
     log::info!("server initialized, serving requests");
     {
         let task_sender = task_sender;
-        let libdata_sender = libdata_sender;
         loop {
             log::trace!("selecting");
             let event = select! {
@@ -192,7 +182,6 @@ pub fn main_loop(config: Config, connection: Connection) -> Result<()> {
                     Ok(task) => Event::Vfs(task),
                     Err(RecvError) => return Err("vfs died".into()),
                 },
-                recv(libdata_receiver) -> data => Event::Lib(data.unwrap()),
                 recv(global_state.flycheck.as_ref().map_or(&never(), |it| &it.task_recv)) -> task => match task {
                     Ok(task) => Event::CheckWatcher(task),
                     Err(RecvError) => return Err("check watcher died".into()),
@@ -203,23 +192,14 @@ pub fn main_loop(config: Config, connection: Connection) -> Result<()> {
                     break;
                 };
             }
-            loop_turn(
-                &pool,
-                &task_sender,
-                &libdata_sender,
-                &connection,
-                &mut global_state,
-                &mut loop_state,
-                event,
-            )?;
+            loop_turn(&pool, &task_sender, &connection, &mut global_state, &mut loop_state, event)?;
         }
     }
     global_state.analysis_host.request_cancellation();
     log::info!("waiting for tasks to finish...");
     task_receiver.into_iter().for_each(|task| {
-        on_task(task, &connection.sender, &mut loop_state.pending_requests, &mut global_state)
+        on_task(task, &connection.sender, &mut loop_state.req_queue.incoming, &mut global_state)
     });
-    libdata_receiver.into_iter().for_each(drop);
     log::info!("...tasks have finished");
     log::info!("joining threadpool...");
     pool.join();
@@ -243,7 +223,6 @@ enum Event {
     Msg(Message),
     Task(Task),
     Vfs(VfsTask),
-    Lib(LibraryData),
     CheckWatcher(CheckTask),
 }
 
@@ -279,43 +258,28 @@ impl fmt::Debug for Event {
             Event::Msg(it) => fmt::Debug::fmt(it, f),
             Event::Task(it) => fmt::Debug::fmt(it, f),
             Event::Vfs(it) => fmt::Debug::fmt(it, f),
-            Event::Lib(it) => fmt::Debug::fmt(it, f),
             Event::CheckWatcher(it) => fmt::Debug::fmt(it, f),
         }
     }
 }
 
-#[derive(Debug, Default)]
+type ReqHandler = fn(&mut GlobalState, Response);
+const DO_NOTHING: ReqHandler = |_, _| ();
+type Incoming = lsp_server::Incoming<(&'static str, Instant)>;
+
+#[derive(Default)]
 struct LoopState {
-    next_request_id: u64,
-    pending_responses: FxHashSet<RequestId>,
-    pending_requests: PendingRequests,
+    req_queue: ReqQueue<(&'static str, Instant), ReqHandler>,
     subscriptions: Subscriptions,
-    // We try not to index more than MAX_IN_FLIGHT_LIBS libraries at the same
-    // time to always have a thread ready to react to input.
-    in_flight_libraries: usize,
-    pending_libraries: Vec<(SourceRootId, Vec<(FileId, RelativePathBuf, Arc<String>)>)>,
     workspace_loaded: bool,
     roots_progress_reported: Option<usize>,
     roots_scanned: usize,
     roots_total: usize,
-    configuration_request_id: Option<RequestId>,
-}
-
-impl LoopState {
-    fn next_request_id(&mut self) -> RequestId {
-        self.next_request_id += 1;
-        let res: RequestId = self.next_request_id.into();
-        let inserted = self.pending_responses.insert(res.clone());
-        assert!(inserted);
-        res
-    }
 }
 
 fn loop_turn(
     pool: &ThreadPool,
     task_sender: &Sender<Task>,
-    libdata_sender: &Sender<LibraryData>,
     connection: &Connection,
     global_state: &mut GlobalState,
     loop_state: &mut LoopState,
@@ -333,23 +297,17 @@ fn loop_turn(
 
     match event {
         Event::Task(task) => {
-            on_task(task, &connection.sender, &mut loop_state.pending_requests, global_state);
+            on_task(task, &connection.sender, &mut loop_state.req_queue.incoming, global_state);
             global_state.maybe_collect_garbage();
         }
         Event::Vfs(task) => {
             global_state.vfs.write().handle_task(task);
         }
-        Event::Lib(lib) => {
-            global_state.add_lib(lib);
-            global_state.maybe_collect_garbage();
-            loop_state.in_flight_libraries -= 1;
-            loop_state.roots_scanned += 1;
-        }
         Event::CheckWatcher(task) => on_check_task(task, global_state, task_sender)?,
         Event::Msg(msg) => match msg {
             Message::Request(req) => on_request(
                 global_state,
-                &mut loop_state.pending_requests,
+                &mut loop_state.req_queue.incoming,
                 pool,
                 task_sender,
                 &connection.sender,
@@ -360,66 +318,18 @@ fn loop_turn(
                 on_notification(&connection.sender, global_state, loop_state, not)?;
             }
             Message::Response(resp) => {
-                let removed = loop_state.pending_responses.remove(&resp.id);
-                if !removed {
-                    log::error!("unexpected response: {:?}", resp)
-                }
-
-                if Some(&resp.id) == loop_state.configuration_request_id.as_ref() {
-                    loop_state.configuration_request_id = None;
-                    log::debug!("config update response: '{:?}", resp);
-                    let Response { error, result, .. } = resp;
-
-                    match (error, result) {
-                        (Some(err), _) => {
-                            log::error!("failed to fetch the server settings: {:?}", err)
-                        }
-                        (None, Some(configs)) => {
-                            if let Some(new_config) = configs.get(0) {
-                                let mut config = global_state.config.clone();
-                                config.update(&new_config);
-                                global_state.update_configuration(config);
-                            }
-                        }
-                        (None, None) => {
-                            log::error!("received empty server settings response from the client")
-                        }
-                    }
-                }
+                let handler = loop_state.req_queue.outgoing.complete(resp.id.clone());
+                handler(global_state, resp)
             }
         },
     };
 
-    let mut state_changed = false;
-    if let Some(changes) = global_state.process_changes(&mut loop_state.roots_scanned) {
-        state_changed = true;
-        loop_state.pending_libraries.extend(changes);
-    }
-
-    let max_in_flight_libs = pool.max_count().saturating_sub(2).max(1);
-    while loop_state.in_flight_libraries < max_in_flight_libs {
-        let (root, files) = match loop_state.pending_libraries.pop() {
-            Some(it) => it,
-            None => break,
-        };
-
-        loop_state.in_flight_libraries += 1;
-        let sender = libdata_sender.clone();
-        pool.execute(move || {
-            log::info!("indexing {:?} ... ", root);
-            let data = LibraryData::prepare(root, files);
-            sender.send(data).unwrap();
-        });
-    }
+    let mut state_changed = global_state.process_changes(&mut loop_state.roots_scanned);
 
     let show_progress =
         !loop_state.workspace_loaded && global_state.config.client_caps.work_done_progress;
 
-    if !loop_state.workspace_loaded
-        && loop_state.roots_scanned == loop_state.roots_total
-        && loop_state.pending_libraries.is_empty()
-        && loop_state.in_flight_libraries == 0
-    {
+    if !loop_state.workspace_loaded && loop_state.roots_scanned == loop_state.roots_total {
         state_changed = true;
         loop_state.workspace_loaded = true;
         if let Some(flycheck) = &global_state.flycheck {
@@ -463,14 +373,19 @@ fn loop_turn(
 fn on_task(
     task: Task,
     msg_sender: &Sender<Message>,
-    pending_requests: &mut PendingRequests,
+    incoming_requests: &mut Incoming,
     state: &mut GlobalState,
 ) {
     match task {
         Task::Respond(response) => {
-            if let Some(completed) = pending_requests.finish(&response.id) {
-                log::info!("handled req#{} in {:?}", completed.id, completed.duration);
-                state.complete_request(completed);
+            if let Some((method, start)) = incoming_requests.complete(response.id.clone()) {
+                let duration = start.elapsed();
+                log::info!("handled req#{} in {:?}", response.id, duration);
+                state.complete_request(RequestMetrics {
+                    id: response.id.clone(),
+                    method: method.to_string(),
+                    duration,
+                });
                 msg_sender.send(response.into()).unwrap();
             }
         }
@@ -483,7 +398,7 @@ fn on_task(
 
 fn on_request(
     global_state: &mut GlobalState,
-    pending_requests: &mut PendingRequests,
+    incoming_requests: &mut Incoming,
     pool: &ThreadPool,
     task_sender: &Sender<Task>,
     msg_sender: &Sender<Message>,
@@ -496,7 +411,7 @@ fn on_request(
         global_state,
         task_sender,
         msg_sender,
-        pending_requests,
+        incoming_requests,
         request_received,
     };
     pool_dispatcher
@@ -560,12 +475,7 @@ fn on_notification(
                 NumberOrString::Number(id) => id.into(),
                 NumberOrString::String(id) => id.into(),
             };
-            if loop_state.pending_requests.cancel(&id) {
-                let response = Response::new_err(
-                    id,
-                    ErrorCode::RequestCanceled as i32,
-                    "canceled by client".to_string(),
-                );
+            if let Some(response) = loop_state.req_queue.incoming.cancel(id) {
                 msg_sender.send(response.into()).unwrap()
             }
             return Ok(());
@@ -628,18 +538,36 @@ fn on_notification(
         Ok(_) => {
             // As stated in https://github.com/microsoft/language-server-protocol/issues/676,
             // this notification's parameters should be ignored and the actual config queried separately.
-            let request_id = loop_state.next_request_id();
-            let request = request_new::<lsp_types::request::WorkspaceConfiguration>(
-                request_id.clone(),
+            let request = loop_state.req_queue.outgoing.register(
+                lsp_types::request::WorkspaceConfiguration::METHOD.to_string(),
                 lsp_types::ConfigurationParams {
                     items: vec![lsp_types::ConfigurationItem {
                         scope_uri: None,
                         section: Some("rust-analyzer".to_string()),
                     }],
                 },
+                |global_state, resp| {
+                    log::debug!("config update response: '{:?}", resp);
+                    let Response { error, result, .. } = resp;
+
+                    match (error, result) {
+                        (Some(err), _) => {
+                            log::error!("failed to fetch the server settings: {:?}", err)
+                        }
+                        (None, Some(configs)) => {
+                            if let Some(new_config) = configs.get(0) {
+                                let mut config = global_state.config.clone();
+                                config.update(&new_config);
+                                global_state.update_configuration(config);
+                            }
+                        }
+                        (None, None) => {
+                            log::error!("received empty server settings response from the client")
+                        }
+                    }
+                },
             );
             msg_sender.send(request.into())?;
-            loop_state.configuration_request_id = Some(request_id);
 
             return Ok(());
         }
@@ -808,13 +736,14 @@ fn send_startup_progress(sender: &Sender<Message>, loop_state: &mut LoopState) {
 
     match (prev, loop_state.workspace_loaded) {
         (None, false) => {
-            let work_done_progress_create = request_new::<lsp_types::request::WorkDoneProgressCreate>(
-                loop_state.next_request_id(),
+            let request = loop_state.req_queue.outgoing.register(
+                lsp_types::request::WorkDoneProgressCreate::METHOD.to_string(),
                 WorkDoneProgressCreateParams {
                     token: lsp_types::ProgressToken::String("rustAnalyzer/startup".into()),
                 },
+                DO_NOTHING,
             );
-            sender.send(work_done_progress_create.into()).unwrap();
+            sender.send(request.into()).unwrap();
             send_startup_progress_notif(
                 sender,
                 WorkDoneProgress::Begin(WorkDoneProgressBegin {
@@ -856,7 +785,7 @@ struct PoolDispatcher<'a> {
     req: Option<Request>,
     pool: &'a ThreadPool,
     global_state: &'a mut GlobalState,
-    pending_requests: &'a mut PendingRequests,
+    incoming_requests: &'a mut Incoming,
     msg_sender: &'a Sender<Message>,
     task_sender: &'a Sender<Task>,
     request_received: Instant,
@@ -885,7 +814,7 @@ impl<'a> PoolDispatcher<'a> {
             result_to_task::<R>(id, result)
         })
         .map_err(|_| format!("sync task {:?} panicked", R::METHOD))?;
-        on_task(task, self.msg_sender, self.pending_requests, self.global_state);
+        on_task(task, self.msg_sender, self.incoming_requests, self.global_state);
         Ok(self)
     }
 
@@ -932,11 +861,7 @@ impl<'a> PoolDispatcher<'a> {
                 return None;
             }
         };
-        self.pending_requests.start(PendingRequest {
-            id: id.clone(),
-            method: R::METHOD.to_string(),
-            received: self.request_received,
-        });
+        self.incoming_requests.register(id.clone(), (R::METHOD, self.request_received));
         Some((id, params))
     }
 
@@ -1049,14 +974,6 @@ where
     Notification::new(N::METHOD.to_string(), params)
 }
 
-fn request_new<R>(id: RequestId, params: R::Params) -> Request
-where
-    R: lsp_types::request::Request,
-    R::Params: Serialize,
-{
-    Request::new(id, R::METHOD.to_string(), params)
-}
-
 #[cfg(test)]
 mod tests {
     use std::borrow::Cow;
diff --git a/crates/rust-analyzer/src/main_loop/handlers.rs b/crates/rust-analyzer/src/main_loop/handlers.rs
index b34b529b5..2d7e649d2 100644
--- a/crates/rust-analyzer/src/main_loop/handlers.rs
+++ b/crates/rust-analyzer/src/main_loop/handlers.rs
@@ -18,8 +18,8 @@ use lsp_types::{
     TextDocumentIdentifier, Url, WorkspaceEdit,
 };
 use ra_ide::{
-    FileId, FilePosition, FileRange, HoverAction, Query, RangeInfo, Runnable, RunnableKind,
-    SearchScope, TextEdit,
+    FileId, FilePosition, FileRange, HoverAction, HoverGotoTypeData, NavigationTarget, Query,
+    RangeInfo, Runnable, RunnableKind, SearchScope, TextEdit,
 };
 use ra_prof::profile;
 use ra_project_model::TargetKind;
@@ -1150,6 +1150,23 @@ fn debug_single_command(runnable: &lsp_ext::Runnable) -> Command {
     }
 }
 
+fn goto_location_command(snap: &GlobalStateSnapshot, nav: &NavigationTarget) -> Option<Command> {
+    let value = if snap.config.client_caps.location_link {
+        let link = to_proto::location_link(snap, None, nav.clone()).ok()?;
+        to_value(link).ok()?
+    } else {
+        let range = FileRange { file_id: nav.file_id(), range: nav.range() };
+        let location = to_proto::location(snap, range).ok()?;
+        to_value(location).ok()?
+    };
+
+    Some(Command {
+        title: nav.name().to_string(),
+        command: "rust-analyzer.gotoLocation".into(),
+        arguments: Some(vec![value]),
+    })
+}
+
 fn to_command_link(command: Command, tooltip: String) -> lsp_ext::CommandLink {
     lsp_ext::CommandLink { tooltip: Some(tooltip), command }
 }
@@ -1180,13 +1197,13 @@ fn show_impl_command_link(
     None
 }
 
-fn to_runnable_action(
+fn runnable_action_links(
     snap: &GlobalStateSnapshot,
     file_id: FileId,
     runnable: Runnable,
 ) -> Option<lsp_ext::CommandLinkGroup> {
     let cargo_spec = CargoTargetSpec::for_file(&snap, file_id).ok()?;
-    if should_skip_target(&runnable, cargo_spec.as_ref()) {
+    if !snap.config.hover.runnable() || should_skip_target(&runnable, cargo_spec.as_ref()) {
         return None;
     }
 
@@ -1208,6 +1225,26 @@ fn to_runnable_action(
     })
 }
 
+fn goto_type_action_links(
+    snap: &GlobalStateSnapshot,
+    nav_targets: &[HoverGotoTypeData],
+) -> Option<lsp_ext::CommandLinkGroup> {
+    if !snap.config.hover.goto_type_def || nav_targets.is_empty() {
+        return None;
+    }
+
+    Some(lsp_ext::CommandLinkGroup {
+        title: Some("Go to ".into()),
+        commands: nav_targets
+            .iter()
+            .filter_map(|it| {
+                goto_location_command(snap, &it.nav)
+                    .map(|cmd| to_command_link(cmd, it.mod_path.clone()))
+            })
+            .collect(),
+    })
+}
+
 fn prepare_hover_actions(
     snap: &GlobalStateSnapshot,
     file_id: FileId,
@@ -1221,7 +1258,8 @@ fn prepare_hover_actions(
         .iter()
         .filter_map(|it| match it {
             HoverAction::Implementaion(position) => show_impl_command_link(snap, position),
-            HoverAction::Runnable(r) => to_runnable_action(snap, file_id, r.clone()),
+            HoverAction::Runnable(r) => runnable_action_links(snap, file_id, r.clone()),
+            HoverAction::GoToType(targets) => goto_type_action_links(snap, targets),
         })
         .collect()
 }
diff --git a/crates/rust-analyzer/src/main_loop/pending_requests.rs b/crates/rust-analyzer/src/main_loop/pending_requests.rs
deleted file mode 100644
index 73b33e419..000000000
--- a/crates/rust-analyzer/src/main_loop/pending_requests.rs
+++ /dev/null
@@ -1,75 +0,0 @@
-//! Data structures that keep track of inflight requests.
-
-use std::time::{Duration, Instant};
-
-use lsp_server::RequestId;
-use rustc_hash::FxHashMap;
-
-#[derive(Debug)]
-pub struct CompletedRequest {
-    pub id: RequestId,
-    pub method: String,
-    pub duration: Duration,
-}
-
-#[derive(Debug)]
-pub(crate) struct PendingRequest {
-    pub(crate) id: RequestId,
-    pub(crate) method: String,
-    pub(crate) received: Instant,
-}
-
-impl From<PendingRequest> for CompletedRequest {
-    fn from(pending: PendingRequest) -> CompletedRequest {
-        CompletedRequest {
-            id: pending.id,
-            method: pending.method,
-            duration: pending.received.elapsed(),
-        }
-    }
-}
-
-#[derive(Debug, Default)]
-pub(crate) struct PendingRequests {
-    map: FxHashMap<RequestId, PendingRequest>,
-}
-
-impl PendingRequests {
-    pub(crate) fn start(&mut self, request: PendingRequest) {
-        let id = request.id.clone();
-        let prev = self.map.insert(id.clone(), request);
-        assert!(prev.is_none(), "duplicate request with id {}", id);
-    }
-    pub(crate) fn cancel(&mut self, id: &RequestId) -> bool {
-        self.map.remove(id).is_some()
-    }
-    pub(crate) fn finish(&mut self, id: &RequestId) -> Option<CompletedRequest> {
-        self.map.remove(id).map(CompletedRequest::from)
-    }
-}
-
-const N_COMPLETED_REQUESTS: usize = 10;
-
-#[derive(Debug, Default)]
-pub struct LatestRequests {
-    // hand-rolling VecDeque here to print things in a nicer way
-    buf: [Option<CompletedRequest>; N_COMPLETED_REQUESTS],
-    idx: usize,
-}
-
-impl LatestRequests {
-    pub(crate) fn record(&mut self, request: CompletedRequest) {
-        // special case: don't track status request itself
-        if request.method == "rust-analyzer/analyzerStatus" {
-            return;
-        }
-        let idx = self.idx;
-        self.buf[idx] = Some(request);
-        self.idx = (idx + 1) % N_COMPLETED_REQUESTS;
-    }
-
-    pub(crate) fn iter(&self) -> impl Iterator<Item = (bool, &CompletedRequest)> {
-        let idx = self.idx;
-        self.buf.iter().enumerate().filter_map(move |(i, req)| Some((i == idx, req.as_ref()?)))
-    }
-}
diff --git a/crates/rust-analyzer/src/main_loop/request_metrics.rs b/crates/rust-analyzer/src/main_loop/request_metrics.rs
new file mode 100644
index 000000000..b1019e2d6
--- /dev/null
+++ b/crates/rust-analyzer/src/main_loop/request_metrics.rs
@@ -0,0 +1,37 @@
+//! Records stats about requests
+use std::time::Duration;
+
+use lsp_server::RequestId;
+
+#[derive(Debug)]
+pub(crate) struct RequestMetrics {
+    pub(crate) id: RequestId,
+    pub(crate) method: String,
+    pub(crate) duration: Duration,
+}
+
+const N_COMPLETED_REQUESTS: usize = 10;
+
+#[derive(Debug, Default)]
+pub(crate) struct LatestRequests {
+    // hand-rolling VecDeque here to print things in a nicer way
+    buf: [Option<RequestMetrics>; N_COMPLETED_REQUESTS],
+    idx: usize,
+}
+
+impl LatestRequests {
+    pub(crate) fn record(&mut self, request: RequestMetrics) {
+        // special case: don't track status request itself
+        if request.method == "rust-analyzer/analyzerStatus" {
+            return;
+        }
+        let idx = self.idx;
+        self.buf[idx] = Some(request);
+        self.idx = (idx + 1) % N_COMPLETED_REQUESTS;
+    }
+
+    pub(crate) fn iter(&self) -> impl Iterator<Item = (bool, &RequestMetrics)> {
+        let idx = self.idx;
+        self.buf.iter().enumerate().filter_map(move |(i, req)| Some((i == idx, req.as_ref()?)))
+    }
+}
diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
index 055c97455..ec153097e 100644
--- a/crates/rust-analyzer/src/to_proto.rs
+++ b/crates/rust-analyzer/src/to_proto.rs
@@ -331,6 +331,7 @@ fn semantic_token_type_and_modifiers(
         let modifier = match modifier {
             HighlightModifier::Attribute => semantic_tokens::ATTRIBUTE_MODIFIER,
             HighlightModifier::Definition => lsp_types::SemanticTokenModifier::DECLARATION,
+            HighlightModifier::Documentation => lsp_types::SemanticTokenModifier::DOCUMENTATION,
             HighlightModifier::ControlFlow => semantic_tokens::CONTROL_FLOW,
             HighlightModifier::Mutable => semantic_tokens::MUTABLE,
             HighlightModifier::Unsafe => semantic_tokens::UNSAFE,
diff --git a/crates/stdx/src/lib.rs b/crates/stdx/src/lib.rs
index c0356344c..f2ff0e435 100644
--- a/crates/stdx/src/lib.rs
+++ b/crates/stdx/src/lib.rs
@@ -1,5 +1,4 @@
 //! Missing batteries for standard libraries.
-
 use std::{cell::Cell, fmt, time::Instant};
 
 #[inline(always)]
diff --git a/crates/vfs/src/file_set.rs b/crates/vfs/src/file_set.rs
index 7dc721f7e..724606a3d 100644
--- a/crates/vfs/src/file_set.rs
+++ b/crates/vfs/src/file_set.rs
@@ -2,7 +2,7 @@
 //!
 //! Files which do not belong to any explicitly configured `FileSet` belong to
 //! the default `FileSet`.
-use std::{cmp, fmt, iter};
+use std::{fmt, iter};
 
 use paths::AbsPathBuf;
 use rustc_hash::FxHashMap;
@@ -44,6 +44,12 @@ pub struct FileSetConfig {
     roots: Vec<(AbsPathBuf, usize)>,
 }
 
+impl Default for FileSetConfig {
+    fn default() -> Self {
+        FileSetConfig::builder().build()
+    }
+}
+
 impl FileSetConfig {
     pub fn builder() -> FileSetConfigBuilder {
         FileSetConfigBuilder::default()
@@ -60,14 +66,19 @@ impl FileSetConfig {
         self.n_file_sets
     }
     fn classify(&self, path: &VfsPath) -> usize {
-        for (root, idx) in self.roots.iter() {
-            if let Some(path) = path.as_path() {
-                if path.starts_with(root) {
-                    return *idx;
-                }
-            }
+        let path = match path.as_path() {
+            Some(it) => it,
+            None => return self.len() - 1,
+        };
+        let idx = match self.roots.binary_search_by(|(p, _)| p.as_path().cmp(path)) {
+            Ok(it) => it,
+            Err(it) => it.saturating_sub(1),
+        };
+        if path.starts_with(&self.roots[idx].0) {
+            self.roots[idx].1
+        } else {
+            self.len() - 1
         }
-        self.len() - 1
     }
 }
 
@@ -82,6 +93,9 @@ impl Default for FileSetConfigBuilder {
 }
 
 impl FileSetConfigBuilder {
+    pub fn len(&self) -> usize {
+        self.roots.len()
+    }
     pub fn add_file_set(&mut self, roots: Vec<AbsPathBuf>) {
         self.roots.push(roots)
     }
@@ -93,7 +107,7 @@ impl FileSetConfigBuilder {
             .enumerate()
             .flat_map(|(i, paths)| paths.into_iter().zip(iter::repeat(i)))
             .collect();
-        roots.sort_by_key(|(path, _)| cmp::Reverse(path.to_string_lossy().len()));
+        roots.sort();
         FileSetConfig { n_file_sets, roots }
     }
 }
diff --git a/crates/vfs/src/lib.rs b/crates/vfs/src/lib.rs
index 75ce61cf9..055219b0c 100644
--- a/crates/vfs/src/lib.rs
+++ b/crates/vfs/src/lib.rs
@@ -79,6 +79,9 @@ pub enum ChangeKind {
 }
 
 impl Vfs {
+    pub fn len(&self) -> usize {
+        self.data.len()
+    }
     pub fn file_id(&self, path: &VfsPath) -> Option<FileId> {
         self.interner.get(path).filter(|&it| self.get(it).is_some())
     }
diff --git a/editors/code/package.json b/editors/code/package.json
index 3acc375f6..e6ceb235f 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -510,6 +510,11 @@
                     "type": "boolean",
                     "default": true
                 },
+                "rust-analyzer.hoverActions.gotoTypeDef": {
+                    "markdownDescription": "Whether to show `Go to Type Definition` action. Only applies when `#rust-analyzer.hoverActions.enable#` is set.",
+                    "type": "boolean",
+                    "default": true
+                },
                 "rust-analyzer.linkedProjects": {
                     "markdownDescription": "Disable project auto-discovery in favor of explicitly specified set of projects.  \nElements must be paths pointing to Cargo.toml, rust-project.json, or JSON objects in rust-project.json format",
                     "type": "array",
diff --git a/editors/code/src/commands.ts b/editors/code/src/commands.ts
index 3e9c3aa0e..48a25495f 100644
--- a/editors/code/src/commands.ts
+++ b/editors/code/src/commands.ts
@@ -353,6 +353,20 @@ export function applyActionGroup(_ctx: Ctx): Cmd {
     };
 }
 
+export function gotoLocation(ctx: Ctx): Cmd {
+    return async (locationLink: lc.LocationLink) => {
+        const client = ctx.client;
+        if (client) {
+            const uri = client.protocol2CodeConverter.asUri(locationLink.targetUri);
+            let range = client.protocol2CodeConverter.asRange(locationLink.targetSelectionRange);
+            // collapse the range to a cursor position
+            range = range.with({ end: range.start });
+
+            await vscode.window.showTextDocument(uri, { selection: range });
+        }
+    };
+}
+
 export function resolveCodeAction(ctx: Ctx): Cmd {
     const client = ctx.client;
     return async (params: ra.ResolveCodeActionParams) => {
diff --git a/editors/code/src/config.ts b/editors/code/src/config.ts
index d8f0037d4..9591d4fe3 100644
--- a/editors/code/src/config.ts
+++ b/editors/code/src/config.ts
@@ -117,7 +117,7 @@ export class Config {
         return {
             engine: this.get<string>("debug.engine"),
             engineSettings: this.get<object>("debug.engineSettings"),
-            openUpDebugPane: this.get<boolean>("debug.openUpDebugPane"),
+            openDebugPane: this.get<boolean>("debug.openDebugPane"),
             sourceFileMap: sourceFileMap
         };
     }
@@ -135,6 +135,9 @@ export class Config {
         return {
             enable: this.get<boolean>("hoverActions.enable"),
             implementations: this.get<boolean>("hoverActions.implementations"),
+            run: this.get<boolean>("hoverActions.run"),
+            debug: this.get<boolean>("hoverActions.debug"),
+            gotoTypeDef: this.get<boolean>("hoverActions.gotoTypeDef"),
         };
     }
 }
diff --git a/editors/code/src/debug.ts b/editors/code/src/debug.ts
index a0c9b3ab2..61c12dbe0 100644
--- a/editors/code/src/debug.ts
+++ b/editors/code/src/debug.ts
@@ -82,7 +82,7 @@ async function getDebugConfiguration(ctx: Ctx, runnable: ra.Runnable): Promise<v
     }
 
     debugOutput.clear();
-    if (ctx.config.debug.openUpDebugPane) {
+    if (ctx.config.debug.openDebugPane) {
         debugOutput.show(true);
     }
 
diff --git a/editors/code/src/main.ts b/editors/code/src/main.ts
index a92c676fa..670f2ebfd 100644
--- a/editors/code/src/main.ts
+++ b/editors/code/src/main.ts
@@ -42,7 +42,16 @@ export async function activate(context: vscode.ExtensionContext) {
 
     const config = new Config(context);
     const state = new PersistentState(context.globalState);
-    const serverPath = await bootstrap(config, state);
+    const serverPath = await bootstrap(config, state).catch(err => {
+        let message = "Failed to bootstrap rust-analyzer.";
+        if (err.code === "EBUSY" || err.code === "ETXTBSY") {
+            message += " Other vscode windows might be using rust-analyzer, " +
+                "you should close them and reload this window to retry.";
+        }
+        message += " Open \"Help > Toggle Developer Tools > Console\" to see the logs";
+        log.error("Bootstrap error", err);
+        throw new Error(message);
+    });
 
     const workspaceFolder = vscode.workspace.workspaceFolders?.[0];
     if (workspaceFolder === undefined) {
@@ -100,6 +109,7 @@ export async function activate(context: vscode.ExtensionContext) {
     ctx.registerCommand('applySnippetWorkspaceEdit', commands.applySnippetWorkspaceEditCommand);
     ctx.registerCommand('resolveCodeAction', commands.resolveCodeAction);
     ctx.registerCommand('applyActionGroup', commands.applyActionGroup);
+    ctx.registerCommand('gotoLocation', commands.gotoLocation);
 
     ctx.pushCleanup(activateTaskProvider(workspaceFolder));
 
@@ -284,6 +294,11 @@ async function getServer(config: Config, state: PersistentState): Promise<string
     const artifact = release.assets.find(artifact => artifact.name === binaryName);
     assert(!!artifact, `Bad release: ${JSON.stringify(release)}`);
 
+    // Unlinking the exe file before moving new one on its place should prevent ETXTBSY error.
+    await fs.unlink(dest).catch(err => {
+        if (err.code !== "ENOENT") throw err;
+    });
+
     await download(artifact.browser_download_url, dest, "Downloading rust-analyzer server", { mode: 0o755 });
 
     // Patching executable if that's NixOS.
diff --git a/editors/code/src/net.ts b/editors/code/src/net.ts
index 492213937..0e7dd29c2 100644
--- a/editors/code/src/net.ts
+++ b/editors/code/src/net.ts
@@ -1,7 +1,9 @@
 import fetch from "node-fetch";
 import * as vscode from "vscode";
-import * as fs from "fs";
 import * as stream from "stream";
+import * as fs from "fs";
+import * as os from "os";
+import * as path from "path";
 import * as util from "util";
 import { log, assert } from "./util";
 
@@ -87,7 +89,7 @@ export async function download(
 }
 
 /**
- * Downloads file from `url` and stores it at `destFilePath` with `destFilePermissions`.
+ * Downloads file from `url` and stores it at `destFilePath` with `mode` (unix permissions).
  * `onProgress` callback is called on recieveing each chunk of bytes
  * to track the progress of downloading, it gets the already read and total
  * amount of bytes to read as its parameters.
@@ -118,14 +120,46 @@ async function downloadFile(
         onProgress(readBytes, totalBytes);
     });
 
-    const destFileStream = fs.createWriteStream(destFilePath, { mode });
+    // Put the artifact into a temporary folder to prevent partially downloaded files when user kills vscode
+    await withTempFile(async tempFilePath => {
+        const destFileStream = fs.createWriteStream(tempFilePath, { mode });
+        await pipeline(res.body, destFileStream);
+        await new Promise<void>(resolve => {
+            destFileStream.on("close", resolve);
+            destFileStream.destroy();
+            // This workaround is awaiting to be removed when vscode moves to newer nodejs version:
+            // https://github.com/rust-analyzer/rust-analyzer/issues/3167
+        });
+        await moveFile(tempFilePath, destFilePath);
+    });
+}
 
-    await pipeline(res.body, destFileStream);
-    return new Promise<void>(resolve => {
-        destFileStream.on("close", resolve);
-        destFileStream.destroy();
+async function withTempFile(scope: (tempFilePath: string) => Promise<void>) {
+    // Based on the great article: https://advancedweb.hu/secure-tempfiles-in-nodejs-without-dependencies/
 
-        // Details on workaround: https://github.com/rust-analyzer/rust-analyzer/pull/3092#discussion_r378191131
-        // Issue at nodejs repo: https://github.com/nodejs/node/issues/31776
-    });
+    // `.realpath()` should handle the cases where os.tmpdir() contains symlinks
+    const osTempDir = await fs.promises.realpath(os.tmpdir());
+
+    const tempDir = await fs.promises.mkdtemp(path.join(osTempDir, "rust-analyzer"));
+
+    try {
+        return await scope(path.join(tempDir, "file"));
+    } finally {
+        // We are good citizens :D
+        void fs.promises.rmdir(tempDir, { recursive: true }).catch(log.error);
+    }
+};
+
+async function moveFile(src: fs.PathLike, dest: fs.PathLike) {
+    try {
+        await fs.promises.rename(src, dest);
+    } catch (err) {
+        if (err.code === 'EXDEV') {
+            // We are probably moving the file across partitions/devices
+            await fs.promises.copyFile(src, dest);
+            await fs.promises.unlink(src);
+        } else {
+            log.error(`Failed to rename the file ${src} -> ${dest}`, err);
+        }
+    }
 }