82 files changed, 2745 insertions, 709 deletions

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,