Merge branch 'master' of github.com:rust-analyzer/rust-analyzer into flip-binexpr

28 files changed, 1017 insertions, 817 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 3bc5f261c..00f2338c9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -913,7 +913,7 @@ dependencies = [
  "ra_hir 0.1.0",
  "ra_project_model 0.1.0",
  "ra_syntax 0.1.0",
- "ra_vfs 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ra_vfs 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "test_utils 0.1.0",
 ]
@@ -1021,7 +1021,7 @@ dependencies = [
  "ra_project_model 0.1.0",
  "ra_syntax 0.1.0",
  "ra_text_edit 0.1.0",
- "ra_vfs 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ra_vfs 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "relative-path 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.89 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1103,7 +1103,7 @@ dependencies = [
 
 [[package]]
 name = "ra_vfs"
-version = "0.2.0"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "crossbeam-channel 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1943,7 +1943,7 @@ dependencies = [
 "checksum proptest 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)" = "24f5844db2f839e97e3021980975f6ebf8691d9b9b2ca67ed3feb38dc3edb52c"
 "checksum quick-error 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "9274b940887ce9addde99c4eee6b5c44cc494b182b97e73dc8ffdcb3397fd3f0"
 "checksum quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)" = "cdd8e04bd9c52e0342b406469d494fcb033be4bdbe5c606016defbb1681411e1"
-"checksum ra_vfs 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "bb1839e4e003d865b58b8b6c231aae6c463dfcd01bfbbddffbdb7662a7b5a627"
+"checksum ra_vfs 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d75d08da053ec832676686c72dfe509fdd1e807191a50ac79087466ffefccb1c"
 "checksum rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)" = "6d71dacdc3c88c1fde3885a3be3fbab9f35724e6ce99467f7d9c5026132184ca"
 "checksum rand_chacha 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "556d3a1ca6600bfcbab7c7c91ccb085ac7fbbcd70e008a98742e7847f4f7bcef"
 "checksum rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6fdeb83b075e8266dcc8762c22776f6877a63111121f5f8c7411e5be7eed4b"
diff --git a/README.md b/README.md
index 3a0c9dee1..8df991246 100644
--- a/README.md
+++ b/README.md
@@ -51,6 +51,12 @@ We are on the rust-lang Zulip!
 
 https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Frls-2.2E0
 
+## Quick Links
+
+* Work List: https://paper.dropbox.com/doc/RLS-2.0-work-list--AZ3BgHKKCtqszbsi3gi6sjchAQ-42vbnxzuKq2lKwW0mkn8Y
+* API docs: https://rust-analyzer.github.io/rust-analyzer/ra_ide_api/index.html
+* CI: https://travis-ci.org/rust-analyzer/rust-analyzer
+
 ## License
 
 Rust analyzer is primarily distributed under the terms of both the MIT
diff --git a/crates/ra_hir/src/code_model_api.rs b/crates/ra_hir/src/code_model_api.rs
index 5437133b8..624c25c4d 100644
--- a/crates/ra_hir/src/code_model_api.rs
+++ b/crates/ra_hir/src/code_model_api.rs
@@ -13,10 +13,11 @@ use crate::{
     adt::{EnumVariantId, StructFieldId, VariantDef},
     generics::GenericParams,
     docs::{Documentation, Docs, docs_from_ast},
-    ids::{FunctionId, StructId, EnumId, AstItemDef, ConstId, StaticId, TraitId, TypeId},
+    ids::{FunctionId, StructId, EnumId, AstItemDef, ConstId, StaticId, TraitId, TypeAliasId},
     impl_block::ImplBlock,
     resolve::Resolver,
     diagnostics::DiagnosticSink,
+    traits::{TraitItem, TraitData},
 };
 
 /// hir::Crate describes a single crate. It's the main interface with which
@@ -649,6 +650,18 @@ impl Trait {
     pub fn generic_params(&self, db: &impl DefDatabase) -> Arc<GenericParams> {
         db.generic_params((*self).into())
     }
+
+    pub fn name(self, db: &impl DefDatabase) -> Option<Name> {
+        self.trait_data(db).name().clone()
+    }
+
+    pub fn items(self, db: &impl DefDatabase) -> Vec<TraitItem> {
+        self.trait_data(db).items().to_vec()
+    }
+
+    pub(crate) fn trait_data(self, db: &impl DefDatabase) -> Arc<TraitData> {
+        db.trait_data(self)
+    }
 }
 
 impl Docs for Trait {
@@ -659,7 +672,7 @@ impl Docs for Trait {
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct TypeAlias {
-    pub(crate) id: TypeId,
+    pub(crate) id: TypeAliasId,
 }
 
 impl TypeAlias {
diff --git a/crates/ra_hir/src/code_model_impl/module.rs b/crates/ra_hir/src/code_model_impl/module.rs
index 14237060c..0edb8ade5 100644
--- a/crates/ra_hir/src/code_model_impl/module.rs
+++ b/crates/ra_hir/src/code_model_impl/module.rs
@@ -1,18 +1,18 @@
 use ra_db::FileId;
-use ra_syntax::{ast, TreeArc, AstNode};
+use ra_syntax::{ast, TreeArc};
 
 use crate::{
-    Module, ModuleSource, Name,
+    Module, ModuleSource, Name, AstId,
     nameres::{CrateModuleId, ImportId},
     HirDatabase, DefDatabase,
-    HirFileId, SourceItemId,
+    HirFileId,
 };
 
 impl ModuleSource {
     pub(crate) fn new(
         db: &impl DefDatabase,
         file_id: Option<FileId>,
-        decl_id: Option<SourceItemId>,
+        decl_id: Option<AstId<ast::Module>>,
     ) -> ModuleSource {
         match (file_id, decl_id) {
             (Some(file_id), _) => {
@@ -20,8 +20,7 @@ impl ModuleSource {
                 ModuleSource::SourceFile(source_file)
             }
             (None, Some(item_id)) => {
-                let module = db.file_item(item_id);
-                let module = ast::Module::cast(&*module).unwrap();
+                let module = item_id.to_node(db);
                 assert!(module.item_list().is_some(), "expected inline module");
                 ModuleSource::Module(module.to_owned())
             }
@@ -55,7 +54,7 @@ impl Module {
         let decl_id = def_map[self.module_id].declaration;
         let file_id = def_map[self.module_id].definition;
         let module_source = ModuleSource::new(db, file_id, decl_id);
-        let file_id = file_id.map(HirFileId::from).unwrap_or_else(|| decl_id.unwrap().file_id);
+        let file_id = file_id.map(HirFileId::from).unwrap_or_else(|| decl_id.unwrap().file_id());
         (file_id, module_source)
     }
 
@@ -65,9 +64,8 @@ impl Module {
     ) -> Option<(HirFileId, TreeArc<ast::Module>)> {
         let def_map = db.crate_def_map(self.krate);
         let decl = def_map[self.module_id].declaration?;
-        let syntax_node = db.file_item(decl);
-        let ast = ast::Module::cast(&syntax_node).unwrap().to_owned();
-        Some((decl.file_id, ast))
+        let ast = decl.to_node(db);
+        Some((decl.file_id(), ast))
     }
 
     pub(crate) fn import_source_impl(
@@ -76,7 +74,7 @@ impl Module {
         import: ImportId,
     ) -> TreeArc<ast::PathSegment> {
         let (file_id, source) = self.definition_source(db);
-        let (_, source_map) = db.raw_items_with_source_map(file_id.original_file(db));
+        let (_, source_map) = db.raw_items_with_source_map(file_id);
         source_map.get(&source, import)
     }
 
diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
index d3908f8ac..147005848 100644
--- a/crates/ra_hir/src/db.rs
+++ b/crates/ra_hir/src/db.rs
@@ -1,10 +1,10 @@
 use std::sync::Arc;
 
 use ra_syntax::{SyntaxNode, TreeArc, SourceFile};
-use ra_db::{SourceDatabase, salsa, FileId};
+use ra_db::{SourceDatabase, salsa};
 
 use crate::{
-    HirFileId, SourceFileItems, SourceItemId, Crate, Module, HirInterner,
+    HirFileId, MacroDefId, AstIdMap, ErasedFileAstId, Crate, Module, HirInterner,
     Function, FnSignature, ExprScopes, TypeAlias,
     Struct, Enum, StructField,
     Const, ConstSignature, Static,
@@ -14,11 +14,15 @@ use crate::{
     impl_block::{ModuleImplBlocks, ImplSourceMap},
     generics::{GenericParams, GenericDef},
     type_ref::TypeRef,
+    traits::TraitData, Trait, ty::TraitRef
 };
 
 #[salsa::query_group(DefDatabaseStorage)]
 pub trait DefDatabase: SourceDatabase + AsRef<HirInterner> {
-    #[salsa::invoke(HirFileId::hir_parse)]
+    #[salsa::invoke(crate::ids::macro_def_query)]
+    fn macro_def(&self, macro_id: MacroDefId) -> Option<Arc<mbe::MacroRules>>;
+
+    #[salsa::invoke(HirFileId::hir_parse_query)]
     fn hir_parse(&self, file_id: HirFileId) -> TreeArc<SourceFile>;
 
     #[salsa::invoke(crate::adt::StructData::struct_data_query)]
@@ -27,17 +31,23 @@ pub trait DefDatabase: SourceDatabase + AsRef<HirInterner> {
     #[salsa::invoke(crate::adt::EnumData::enum_data_query)]
     fn enum_data(&self, e: Enum) -> Arc<EnumData>;
 
-    #[salsa::invoke(crate::ids::SourceFileItems::file_items_query)]
-    fn file_items(&self, file_id: HirFileId) -> Arc<SourceFileItems>;
+    #[salsa::invoke(crate::traits::TraitData::trait_data_query)]
+    fn trait_data(&self, t: Trait) -> Arc<TraitData>;
+
+    #[salsa::invoke(crate::source_id::AstIdMap::ast_id_map_query)]
+    fn ast_id_map(&self, file_id: HirFileId) -> Arc<AstIdMap>;
 
-    #[salsa::invoke(crate::ids::SourceFileItems::file_item_query)]
-    fn file_item(&self, source_item_id: SourceItemId) -> TreeArc<SyntaxNode>;
+    #[salsa::invoke(crate::source_id::AstIdMap::file_item_query)]
+    fn ast_id_to_node(&self, file_id: HirFileId, ast_id: ErasedFileAstId) -> TreeArc<SyntaxNode>;
 
     #[salsa::invoke(RawItems::raw_items_query)]
-    fn raw_items(&self, file_id: FileId) -> Arc<RawItems>;
+    fn raw_items(&self, file_id: HirFileId) -> Arc<RawItems>;
 
     #[salsa::invoke(RawItems::raw_items_with_source_map_query)]
-    fn raw_items_with_source_map(&self, file_id: FileId) -> (Arc<RawItems>, Arc<ImportSourceMap>);
+    fn raw_items_with_source_map(
+        &self,
+        file_id: HirFileId,
+    ) -> (Arc<RawItems>, Arc<ImportSourceMap>);
 
     #[salsa::invoke(CrateDefMap::crate_def_map_query)]
     fn crate_def_map(&self, krate: Crate) -> Arc<CrateDefMap>;
@@ -98,6 +108,9 @@ pub trait HirDatabase: DefDatabase {
 
     #[salsa::invoke(crate::ty::method_resolution::CrateImplBlocks::impls_in_crate_query)]
     fn impls_in_crate(&self, krate: Crate) -> Arc<CrateImplBlocks>;
+
+    #[salsa::invoke(crate::ty::method_resolution::implements)]
+    fn implements(&self, trait_ref: TraitRef) -> bool;
 }
 
 #[test]
diff --git a/crates/ra_hir/src/ids.rs b/crates/ra_hir/src/ids.rs
index 18401f865..eb9939df7 100644
--- a/crates/ra_hir/src/ids.rs
+++ b/crates/ra_hir/src/ids.rs
@@ -1,16 +1,15 @@
 use std::{
-    marker::PhantomData,
     hash::{Hash, Hasher},
     sync::Arc,
 };
 
 use ra_db::{LocationInterner, FileId};
-use ra_syntax::{TreeArc, SyntaxNode, SourceFile, AstNode, SyntaxNodePtr, ast};
-use ra_arena::{Arena, RawId, ArenaId, impl_arena_id};
+use ra_syntax::{TreeArc, SourceFile, AstNode, ast};
+use ra_arena::{RawId, ArenaId, impl_arena_id};
+use mbe::MacroRules;
 
 use crate::{
-    Module,
-    DefDatabase,
+    Module, DefDatabase, AstId, FileAstId,
 };
 
 #[derive(Debug, Default)]
@@ -22,7 +21,7 @@ pub struct HirInterner {
     consts: LocationInterner<ItemLoc<ast::ConstDef>, ConstId>,
     statics: LocationInterner<ItemLoc<ast::StaticDef>, StaticId>,
     traits: LocationInterner<ItemLoc<ast::TraitDef>, TraitId>,
-    types: LocationInterner<ItemLoc<ast::TypeAliasDef>, TypeId>,
+    types: LocationInterner<ItemLoc<ast::TypeAliasDef>, TypeAliasId>,
 }
 
 impl HirInterner {
@@ -68,7 +67,7 @@ impl HirFileId {
             HirFileIdRepr::File(file_id) => file_id,
             HirFileIdRepr::Macro(macro_call_id) => {
                 let loc = macro_call_id.loc(db);
-                loc.source_item_id.file_id.original_file(db)
+                loc.ast_id.file_id().original_file(db)
             }
         }
     }
@@ -83,7 +82,10 @@ impl HirFileId {
         }
     }
 
-    pub(crate) fn hir_parse(db: &impl DefDatabase, file_id: HirFileId) -> TreeArc<SourceFile> {
+    pub(crate) fn hir_parse_query(
+        db: &impl DefDatabase,
+        file_id: HirFileId,
+    ) -> TreeArc<SourceFile> {
         match file_id.0 {
             HirFileIdRepr::File(file_id) => db.parse(file_id),
             HirFileIdRepr::Macro(macro_call_id) => {
@@ -96,14 +98,10 @@ impl HirFileId {
 
 fn parse_macro(db: &impl DefDatabase, macro_call_id: MacroCallId) -> Option<TreeArc<SourceFile>> {
     let loc = macro_call_id.loc(db);
-    let syntax = db.file_item(loc.source_item_id);
-    let macro_call = ast::MacroCall::cast(&syntax).unwrap();
+    let macro_call = loc.ast_id.to_node(db);
     let (macro_arg, _) = macro_call.token_tree().and_then(mbe::ast_to_token_tree)?;
 
-    let def_map = db.crate_def_map(loc.module.krate);
-    let (krate, macro_id) = def_map.resolve_macro(macro_call_id)?;
-    let def_map = db.crate_def_map(krate);
-    let macro_rules = &def_map[macro_id];
+    let macro_rules = db.macro_def(loc.def)?;
     let tt = macro_rules.expand(&macro_arg).ok()?;
     Some(mbe::token_tree_to_ast_item_list(&tt))
 }
@@ -126,6 +124,17 @@ impl From<MacroCallId> for HirFileId {
     }
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct MacroDefId(pub(crate) AstId<ast::MacroCall>);
+
+pub(crate) fn macro_def_query(db: &impl DefDatabase, id: MacroDefId) -> Option<Arc<MacroRules>> {
+    let macro_call = id.0.to_node(db);
+    let arg = macro_call.token_tree()?;
+    let (tt, _) = mbe::ast_to_token_tree(arg)?;
+    let rules = MacroRules::parse(&tt).ok()?;
+    Some(Arc::new(rules))
+}
+
 /// `MacroCallId` identifies a particular macro invocation, like
 /// `println!("Hello, {}", world)`.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -134,8 +143,8 @@ impl_arena_id!(MacroCallId);
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct MacroCallLoc {
-    pub(crate) module: Module,
-    pub(crate) source_item_id: SourceItemId,
+    pub(crate) def: MacroDefId,
+    pub(crate) ast_id: AstId<ast::MacroCall>,
 }
 
 impl MacroCallId {
@@ -145,7 +154,6 @@ impl MacroCallId {
 }
 
 impl MacroCallLoc {
-    #[allow(unused)]
     pub(crate) fn id(&self, db: &impl AsRef<HirInterner>) -> MacroCallId {
         db.as_ref().macros.loc2id(&self)
     }
@@ -154,26 +162,25 @@ impl MacroCallLoc {
 #[derive(Debug)]
 pub struct ItemLoc<N: AstNode> {
     pub(crate) module: Module,
-    raw: SourceItemId,
-    _ty: PhantomData<N>,
+    ast_id: AstId<N>,
 }
 
 impl<N: AstNode> PartialEq for ItemLoc<N> {
     fn eq(&self, other: &Self) -> bool {
-        self.module == other.module && self.raw == other.raw
+        self.module == other.module && self.ast_id == other.ast_id
     }
 }
 impl<N: AstNode> Eq for ItemLoc<N> {}
 impl<N: AstNode> Hash for ItemLoc<N> {
     fn hash<H: Hasher>(&self, hasher: &mut H) {
         self.module.hash(hasher);
-        self.raw.hash(hasher);
+        self.ast_id.hash(hasher);
     }
 }
 
 impl<N: AstNode> Clone for ItemLoc<N> {
     fn clone(&self) -> ItemLoc<N> {
-        ItemLoc { module: self.module, raw: self.raw, _ty: PhantomData }
+        ItemLoc { module: self.module, ast_id: self.ast_id }
     }
 }
 
@@ -200,26 +207,19 @@ impl<'a, DB: DefDatabase> LocationCtx<&'a DB> {
 pub(crate) trait AstItemDef<N: AstNode>: ArenaId + Clone {
     fn interner(interner: &HirInterner) -> &LocationInterner<ItemLoc<N>, Self>;
     fn from_ast(ctx: LocationCtx<&impl DefDatabase>, ast: &N) -> Self {
-        let items = ctx.db.file_items(ctx.file_id);
-        let item_id = items.id_of(ctx.file_id, ast.syntax());
-        Self::from_source_item_id_unchecked(ctx, item_id)
+        let items = ctx.db.ast_id_map(ctx.file_id);
+        let item_id = items.ast_id(ast);
+        Self::from_ast_id(ctx, item_id)
     }
-    fn from_source_item_id_unchecked(
-        ctx: LocationCtx<&impl DefDatabase>,
-        item_id: SourceFileItemId,
-    ) -> Self {
-        let raw = SourceItemId { file_id: ctx.file_id, item_id };
-        let loc = ItemLoc { module: ctx.module, raw, _ty: PhantomData };
-
+    fn from_ast_id(ctx: LocationCtx<&impl DefDatabase>, ast_id: FileAstId<N>) -> Self {
+        let loc = ItemLoc { module: ctx.module, ast_id: ast_id.with_file_id(ctx.file_id) };
         Self::interner(ctx.db.as_ref()).loc2id(&loc)
     }
     fn source(self, db: &impl DefDatabase) -> (HirFileId, TreeArc<N>) {
         let int = Self::interner(db.as_ref());
         let loc = int.id2loc(self);
-        let syntax = db.file_item(loc.raw);
-        let ast =
-            N::cast(&syntax).unwrap_or_else(|| panic!("invalid ItemLoc: {:?}", loc.raw)).to_owned();
-        (loc.raw.file_id, ast)
+        let ast = loc.ast_id.to_node(db);
+        (loc.ast_id.file_id(), ast)
     }
     fn module(self, db: &impl DefDatabase) -> Module {
         let int = Self::interner(db.as_ref());
@@ -229,7 +229,7 @@ pub(crate) trait AstItemDef<N: AstNode>: ArenaId + Clone {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct FunctionId(RawId);
+pub(crate) struct FunctionId(RawId);
 impl_arena_id!(FunctionId);
 impl AstItemDef<ast::FnDef> for FunctionId {
     fn interner(interner: &HirInterner) -> &LocationInterner<ItemLoc<ast::FnDef>, Self> {
@@ -238,7 +238,7 @@ impl AstItemDef<ast::FnDef> for FunctionId {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct StructId(RawId);
+pub(crate) struct StructId(RawId);
 impl_arena_id!(StructId);
 impl AstItemDef<ast::StructDef> for StructId {
     fn interner(interner: &HirInterner) -> &LocationInterner<ItemLoc<ast::StructDef>, Self> {
@@ -247,7 +247,7 @@ impl AstItemDef<ast::StructDef> for StructId {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct EnumId(RawId);
+pub(crate) struct EnumId(RawId);
 impl_arena_id!(EnumId);
 impl AstItemDef<ast::EnumDef> for EnumId {
     fn interner(interner: &HirInterner) -> &LocationInterner<ItemLoc<ast::EnumDef>, Self> {
@@ -256,7 +256,7 @@ impl AstItemDef<ast::EnumDef> for EnumId {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct ConstId(RawId);
+pub(crate) struct ConstId(RawId);
 impl_arena_id!(ConstId);
 impl AstItemDef<ast::ConstDef> for ConstId {
     fn interner(interner: &HirInterner) -> &LocationInterner<ItemLoc<ast::ConstDef>, Self> {
@@ -265,7 +265,7 @@ impl AstItemDef<ast::ConstDef> for ConstId {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct StaticId(RawId);
+pub(crate) struct StaticId(RawId);
 impl_arena_id!(StaticId);
 impl AstItemDef<ast::StaticDef> for StaticId {
     fn interner(interner: &HirInterner) -> &LocationInterner<ItemLoc<ast::StaticDef>, Self> {
@@ -274,7 +274,7 @@ impl AstItemDef<ast::StaticDef> for StaticId {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct TraitId(RawId);
+pub(crate) struct TraitId(RawId);
 impl_arena_id!(TraitId);
 impl AstItemDef<ast::TraitDef> for TraitId {
     fn interner(interner: &HirInterner) -> &LocationInterner<ItemLoc<ast::TraitDef>, Self> {
@@ -283,117 +283,10 @@ impl AstItemDef<ast::TraitDef> for TraitId {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct TypeId(RawId);
-impl_arena_id!(TypeId);
-impl AstItemDef<ast::TypeAliasDef> for TypeId {
+pub(crate) struct TypeAliasId(RawId);
+impl_arena_id!(TypeAliasId);
+impl AstItemDef<ast::TypeAliasDef> for TypeAliasId {
     fn interner(interner: &HirInterner) -> &LocationInterner<ItemLoc<ast::TypeAliasDef>, Self> {
         &interner.types
     }
 }
-
-/// Identifier of item within a specific file. This is stable over reparses, so
-/// it's OK to use it as a salsa key/value.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct SourceFileItemId(RawId);
-impl_arena_id!(SourceFileItemId);
-
-impl SourceFileItemId {
-    pub(crate) fn with_file_id(self, file_id: HirFileId) -> SourceItemId {
-        SourceItemId { file_id, item_id: self }
-    }
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct SourceItemId {
-    pub(crate) file_id: HirFileId,
-    pub(crate) item_id: SourceFileItemId,
-}
-
-/// Maps items' `SyntaxNode`s to `SourceFileItemId`s and back.
-#[derive(Debug, PartialEq, Eq)]
-pub struct SourceFileItems {
-    file_id: HirFileId,
-    arena: Arena<SourceFileItemId, SyntaxNodePtr>,
-}
-
-impl SourceFileItems {
-    pub(crate) fn file_items_query(
-        db: &impl DefDatabase,
-        file_id: HirFileId,
-    ) -> Arc<SourceFileItems> {
-        let source_file = db.hir_parse(file_id);
-        Arc::new(SourceFileItems::from_source_file(&source_file, file_id))
-    }
-
-    pub(crate) fn file_item_query(
-        db: &impl DefDatabase,
-        source_item_id: SourceItemId,
-    ) -> TreeArc<SyntaxNode> {
-        let source_file = db.hir_parse(source_item_id.file_id);
-        db.file_items(source_item_id.file_id)[source_item_id.item_id]
-            .to_node(&source_file)
-            .to_owned()
-    }
-
-    pub(crate) fn from_source_file(
-        source_file: &SourceFile,
-        file_id: HirFileId,
-    ) -> SourceFileItems {
-        let mut res = SourceFileItems { file_id, arena: Arena::default() };
-        // By walking the tree in bread-first order we make sure that parents
-        // get lower ids then children. That is, adding a new child does not
-        // change parent's id. This means that, say, adding a new function to a
-        // trait does not change ids of top-level items, which helps caching.
-        bfs(source_file.syntax(), |it| {
-            if let Some(module_item) = ast::ModuleItem::cast(it) {
-                res.alloc(module_item.syntax());
-            } else if let Some(macro_call) = ast::MacroCall::cast(it) {
-                res.alloc(macro_call.syntax());
-            }
-        });
-        res
-    }
-
-    fn alloc(&mut self, item: &SyntaxNode) -> SourceFileItemId {
-        self.arena.alloc(SyntaxNodePtr::new(item))
-    }
-    pub(crate) fn id_of(&self, file_id: HirFileId, item: &SyntaxNode) -> SourceFileItemId {
-        assert_eq!(
-            self.file_id, file_id,
-            "SourceFileItems: wrong file, expected {:?}, got {:?}",
-            self.file_id, file_id
-        );
-        self.id_of_unchecked(item)
-    }
-    pub(crate) fn id_of_unchecked(&self, item: &SyntaxNode) -> SourceFileItemId {
-        let ptr = SyntaxNodePtr::new(item);
-        if let Some((id, _)) = self.arena.iter().find(|(_id, i)| **i == ptr) {
-            return id;
-        }
-        panic!(
-            "Can't find {:?} in SourceFileItems:\n{:?}",
-            item,
-            self.arena.iter().map(|(_id, i)| i).collect::<Vec<_>>(),
-        );
-    }
-}
-
-impl std::ops::Index<SourceFileItemId> for SourceFileItems {
-    type Output = SyntaxNodePtr;
-    fn index(&self, idx: SourceFileItemId) -> &SyntaxNodePtr {
-        &self.arena[idx]
-    }
-}
-
-/// Walks the subtree in bfs order, calling `f` for each node.
-fn bfs(node: &SyntaxNode, mut f: impl FnMut(&SyntaxNode)) {
-    let mut curr_layer = vec![node];
-    let mut next_layer = vec![];
-    while !curr_layer.is_empty() {
-        curr_layer.drain(..).for_each(|node| {
-            next_layer.extend(node.children());
-            f(node);
-        });
-        std::mem::swap(&mut curr_layer, &mut next_layer);
-    }
-}
diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
index ce54d7608..7c603bbd3 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -23,10 +23,12 @@ pub mod mock;
 mod path;
 pub mod source_binder;
 
+mod source_id;
 mod ids;
 mod name;
 mod nameres;
 mod adt;
+mod traits;
 mod type_alias;
 mod type_ref;
 mod ty;
@@ -46,13 +48,14 @@ mod marks;
 use crate::{
     db::{HirDatabase, DefDatabase},
     name::{AsName, KnownName},
-    ids::{SourceItemId, SourceFileItems},
+    source_id::{FileAstId, AstId},
 };
 
 pub use self::{
     path::{Path, PathKind},
     name::Name,
-    ids::{HirFileId, MacroCallId, MacroCallLoc, HirInterner},
+    source_id::{AstIdMap, ErasedFileAstId},
+    ids::{HirFileId, MacroDefId, MacroCallId, MacroCallLoc, HirInterner},
     nameres::{PerNs, Namespace},
     ty::{Ty, ApplicationTy, TypeCtor, Substs, display::HirDisplay},
     impl_block::{ImplBlock, ImplItem},
diff --git a/crates/ra_hir/src/nameres.rs b/crates/ra_hir/src/nameres.rs
index 56ed872d5..67b9d6986 100644
--- a/crates/ra_hir/src/nameres.rs
+++ b/crates/ra_hir/src/nameres.rs
@@ -59,13 +59,15 @@ use rustc_hash::FxHashMap;
 use ra_arena::{Arena, RawId, impl_arena_id};
 use ra_db::{FileId, Edition};
 use test_utils::tested_by;
+use ra_syntax::ast;
 
 use crate::{
     ModuleDef, Name, Crate, Module,
-    DefDatabase, Path, PathKind, HirFileId,
-    ids::{SourceItemId, SourceFileItemId, MacroCallId},
+    DefDatabase, Path, PathKind, HirFileId, Trait,
+    ids::MacroDefId,
     diagnostics::DiagnosticSink,
     nameres::diagnostics::DefDiagnostic,
+    AstId,
 };
 
 pub(crate) use self::raw::{RawItems, ImportId, ImportSourceMap};
@@ -84,9 +86,7 @@ pub struct CrateDefMap {
     extern_prelude: FxHashMap<Name, ModuleDef>,
     root: CrateModuleId,
     modules: Arena<CrateModuleId, ModuleData>,
-    macros: Arena<CrateMacroId, mbe::MacroRules>,
-    public_macros: FxHashMap<Name, CrateMacroId>,
-    macro_resolutions: FxHashMap<MacroCallId, (Crate, CrateMacroId)>,
+    public_macros: FxHashMap<Name, MacroDefId>,
     diagnostics: Vec<DefDiagnostic>,
 }
 
@@ -97,18 +97,6 @@ impl std::ops::Index<CrateModuleId> for CrateDefMap {
     }
 }
 
-impl std::ops::Index<CrateMacroId> for CrateDefMap {
-    type Output = mbe::MacroRules;
-    fn index(&self, id: CrateMacroId) -> &mbe::MacroRules {
-        &self.macros[id]
-    }
-}
-
-/// An ID of a macro, **local** to a specific crate
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub(crate) struct CrateMacroId(RawId);
-impl_arena_id!(CrateMacroId);
-
 /// An ID of a module, **local** to a specific crate
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub(crate) struct CrateModuleId(RawId);
@@ -120,7 +108,7 @@ pub(crate) struct ModuleData {
     pub(crate) children: FxHashMap<Name, CrateModuleId>,
     pub(crate) scope: ModuleScope,
     /// None for root
-    pub(crate) declaration: Option<SourceItemId>,
+    pub(crate) declaration: Option<AstId<ast::Module>>,
     /// None for inline modules.
     ///
     /// Note that non-inline modules, by definition, live inside non-macro file.
@@ -139,6 +127,12 @@ impl ModuleScope {
     pub fn get(&self, name: &Name) -> Option<&Resolution> {
         self.items.get(name)
     }
+    pub fn traits<'a>(&'a self) -> impl Iterator<Item = Trait> + 'a {
+        self.items.values().filter_map(|r| match r.def.take_types() {
+            Some(ModuleDef::Trait(t)) => Some(t),
+            _ => None,
+        })
+    }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Default)]
@@ -196,9 +190,7 @@ impl CrateDefMap {
                 prelude: None,
                 root,
                 modules,
-                macros: Arena::default(),
                 public_macros: FxHashMap::default(),
-                macro_resolutions: FxHashMap::default(),
                 diagnostics: Vec::new(),
             }
         };
@@ -232,19 +224,11 @@ impl CrateDefMap {
         self.diagnostics.iter().for_each(|it| it.add_to(db, module, sink))
     }
 
-    pub(crate) fn resolve_macro(
-        &self,
-        macro_call_id: MacroCallId,
-    ) -> Option<(Crate, CrateMacroId)> {
-        self.macro_resolutions.get(&macro_call_id).map(|&it| it)
-    }
-
     pub(crate) fn find_module_by_source(
         &self,
         file_id: HirFileId,
-        decl_id: Option<SourceFileItemId>,
+        decl_id: Option<AstId<ast::Module>>,
     ) -> Option<CrateModuleId> {
-        let decl_id = decl_id.map(|it| it.with_file_id(file_id));
         let (module_id, _module_data) = self.modules.iter().find(|(_module_id, module_data)| {
             if decl_id.is_some() {
                 module_data.declaration == decl_id
@@ -447,10 +431,10 @@ impl CrateDefMap {
 
 mod diagnostics {
     use relative_path::RelativePathBuf;
-    use ra_syntax::{AstPtr, AstNode, ast};
+    use ra_syntax::{AstPtr, ast};
 
     use crate::{
-        SourceItemId, DefDatabase,
+        AstId, DefDatabase,
         nameres::CrateModuleId,
         diagnostics::{DiagnosticSink, UnresolvedModule},
 };
@@ -459,7 +443,7 @@ mod diagnostics {
     pub(super) enum DefDiagnostic {
         UnresolvedModule {
             module: CrateModuleId,
-            declaration: SourceItemId,
+            declaration: AstId<ast::Module>,
             candidate: RelativePathBuf,
         },
     }
@@ -476,10 +460,9 @@ mod diagnostics {
                     if *module != target_module {
                         return;
                     }
-                    let syntax = db.file_item(*declaration);
-                    let decl = ast::Module::cast(&syntax).unwrap();
+                    let decl = declaration.to_node(db);
                     sink.push(UnresolvedModule {
-                        file: declaration.file_id,
+                        file: declaration.file_id(),
                         decl: AstPtr::new(&decl),
                         candidate: candidate.clone(),
                     })
@@ -487,5 +470,4 @@ mod diagnostics {
             }
         }
     }
-
 }
diff --git a/crates/ra_hir/src/nameres/collector.rs b/crates/ra_hir/src/nameres/collector.rs
index 8830b4624..39cadc94a 100644
--- a/crates/ra_hir/src/nameres/collector.rs
+++ b/crates/ra_hir/src/nameres/collector.rs
@@ -3,18 +3,20 @@ use rustc_hash::FxHashMap;
 use relative_path::RelativePathBuf;
 use test_utils::tested_by;
 use ra_db::FileId;
+use ra_syntax::ast;
 
 use crate::{
     Function, Module, Struct, Enum, Const, Static, Trait, TypeAlias,
-    DefDatabase, HirFileId, Name, Path, Crate,
+    DefDatabase, HirFileId, Name, Path,
     KnownName,
     nameres::{
         Resolution, PerNs, ModuleDef, ReachedFixedPoint, ResolveMode,
-        CrateDefMap, CrateModuleId, ModuleData, CrateMacroId,
+        CrateDefMap, CrateModuleId, ModuleData,
         diagnostics::DefDiagnostic,
         raw,
     },
-    ids::{AstItemDef, LocationCtx, MacroCallLoc, SourceItemId, MacroCallId},
+    ids::{AstItemDef, LocationCtx, MacroCallLoc, MacroCallId, MacroDefId},
+    AstId,
 };
 
 pub(super) fn collect_defs(db: &impl DefDatabase, mut def_map: CrateDefMap) -> CrateDefMap {
@@ -51,8 +53,8 @@ struct DefCollector<DB> {
     def_map: CrateDefMap,
     glob_imports: FxHashMap<CrateModuleId, Vec<(CrateModuleId, raw::ImportId)>>,
     unresolved_imports: Vec<(CrateModuleId, raw::ImportId, raw::ImportData)>,
-    unexpanded_macros: Vec<(CrateModuleId, MacroCallId, Path, tt::Subtree)>,
-    global_macro_scope: FxHashMap<Name, CrateMacroId>,
+    unexpanded_macros: Vec<(CrateModuleId, AstId<ast::MacroCall>, Path)>,
+    global_macro_scope: FxHashMap<Name, MacroDefId>,
 }
 
 impl<'a, DB> DefCollector<&'a DB>
@@ -62,7 +64,7 @@ where
     fn collect(&mut self) {
         let crate_graph = self.db.crate_graph();
         let file_id = crate_graph.crate_root(self.def_map.krate.crate_id());
-        let raw_items = self.db.raw_items(file_id);
+        let raw_items = self.db.raw_items(file_id.into());
         let module_id = self.def_map.root;
         self.def_map.modules[module_id].definition = Some(file_id);
         ModCollector {
@@ -93,14 +95,11 @@ where
         }
     }
 
-    fn define_macro(&mut self, name: Name, tt: &tt::Subtree, export: bool) {
-        if let Ok(rules) = mbe::MacroRules::parse(tt) {
-            let macro_id = self.def_map.macros.alloc(rules);
-            if export {
-                self.def_map.public_macros.insert(name.clone(), macro_id);
-            }
-            self.global_macro_scope.insert(name, macro_id);
+    fn define_macro(&mut self, name: Name, macro_id: MacroDefId, export: bool) {
+        if export {
+            self.def_map.public_macros.insert(name.clone(), macro_id);
         }
+        self.global_macro_scope.insert(name, macro_id);
     }
 
     fn resolve_imports(&mut self) -> ReachedFixedPoint {
@@ -296,7 +295,7 @@ where
         let mut macros = std::mem::replace(&mut self.unexpanded_macros, Vec::new());
         let mut resolved = Vec::new();
         let mut res = ReachedFixedPoint::Yes;
-        macros.retain(|(module_id, call_id, path, tt)| {
+        macros.retain(|(module_id, ast_id, path)| {
             if path.segments.len() != 2 {
                 return true;
             }
@@ -312,47 +311,23 @@ where
             res = ReachedFixedPoint::No;
             let def_map = self.db.crate_def_map(krate);
             if let Some(macro_id) = def_map.public_macros.get(&path.segments[1].name).cloned() {
-                resolved.push((*module_id, *call_id, (krate, macro_id), tt.clone()));
+                let call_id = MacroCallLoc { def: macro_id, ast_id: *ast_id }.id(self.db);
+                resolved.push((*module_id, call_id));
             }
             false
         });
 
-        for (module_id, macro_call_id, macro_def_id, arg) in resolved {
-            self.collect_macro_expansion(module_id, macro_call_id, macro_def_id, arg);
+        for (module_id, macro_call_id) in resolved {
+            self.collect_macro_expansion(module_id, macro_call_id);
         }
         res
     }
 
-    fn collect_macro_expansion(
-        &mut self,
-        module_id: CrateModuleId,
-        macro_call_id: MacroCallId,
-        macro_def_id: (Crate, CrateMacroId),
-        macro_arg: tt::Subtree,
-    ) {
-        let (macro_krate, macro_id) = macro_def_id;
-        let dm;
-        let rules = if macro_krate == self.def_map.krate {
-            &self.def_map[macro_id]
-        } else {
-            dm = self.db.crate_def_map(macro_krate);
-            &dm[macro_id]
-        };
-        if let Ok(expansion) = rules.expand(&macro_arg) {
-            self.def_map.macro_resolutions.insert(macro_call_id, macro_def_id);
-            // XXX: this **does not** go through a database, because we can't
-            // identify macro_call without adding the whole state of name resolution
-            // as a parameter to the query.
-            //
-            // So, we run the queries "manually" and we must ensure that
-            // `db.hir_parse(macro_call_id)` returns the same source_file.
-            let file_id: HirFileId = macro_call_id.into();
-            let source_file = mbe::token_tree_to_ast_item_list(&expansion);
-
-            let raw_items = raw::RawItems::from_source_file(&source_file, file_id);
-            ModCollector { def_collector: &mut *self, file_id, module_id, raw_items: &raw_items }
-                .collect(raw_items.items())
-        }
+    fn collect_macro_expansion(&mut self, module_id: CrateModuleId, macro_call_id: MacroCallId) {
+        let file_id: HirFileId = macro_call_id.into();
+        let raw_items = self.db.raw_items(file_id);
+        ModCollector { def_collector: &mut *self, file_id, module_id, raw_items: &raw_items }
+            .collect(raw_items.items())
     }
 
     fn finish(self) -> CrateDefMap {
@@ -390,12 +365,9 @@ where
     fn collect_module(&mut self, module: &raw::ModuleData) {
         match module {
             // inline module, just recurse
-            raw::ModuleData::Definition { name, items, source_item_id } => {
-                let module_id = self.push_child_module(
-                    name.clone(),
-                    source_item_id.with_file_id(self.file_id),
-                    None,
-                );
+            raw::ModuleData::Definition { name, items, ast_id } => {
+                let module_id =
+                    self.push_child_module(name.clone(), ast_id.with_file_id(self.file_id), None);
                 ModCollector {
                     def_collector: &mut *self.def_collector,
                     module_id,
@@ -405,14 +377,13 @@ where
                 .collect(&*items);
             }
             // out of line module, resovle, parse and recurse
-            raw::ModuleData::Declaration { name, source_item_id } => {
-                let source_item_id = source_item_id.with_file_id(self.file_id);
+            raw::ModuleData::Declaration { name, ast_id } => {
+                let ast_id = ast_id.with_file_id(self.file_id);
                 let is_root = self.def_collector.def_map.modules[self.module_id].parent.is_none();
                 match resolve_submodule(self.def_collector.db, self.file_id, name, is_root) {
                     Ok(file_id) => {
-                        let module_id =
-                            self.push_child_module(name.clone(), source_item_id, Some(file_id));
-                        let raw_items = self.def_collector.db.raw_items(file_id);
+                        let module_id = self.push_child_module(name.clone(), ast_id, Some(file_id));
+                        let raw_items = self.def_collector.db.raw_items(file_id.into());
                         ModCollector {
                             def_collector: &mut *self.def_collector,
                             module_id,
@@ -424,7 +395,7 @@ where
                     Err(candidate) => self.def_collector.def_map.diagnostics.push(
                         DefDiagnostic::UnresolvedModule {
                             module: self.module_id,
-                            declaration: source_item_id,
+                            declaration: ast_id,
                             candidate,
                         },
                     ),
@@ -436,7 +407,7 @@ where
     fn push_child_module(
         &mut self,
         name: Name,
-        declaration: SourceItemId,
+        declaration: AstId<ast::Module>,
         definition: Option<FileId>,
     ) -> CrateModuleId {
         let modules = &mut self.def_collector.def_map.modules;
@@ -458,23 +429,24 @@ where
     fn define_def(&mut self, def: &raw::DefData) {
         let module = Module { krate: self.def_collector.def_map.krate, module_id: self.module_id };
         let ctx = LocationCtx::new(self.def_collector.db, module, self.file_id.into());
-        macro_rules! id {
-            () => {
-                AstItemDef::from_source_item_id_unchecked(ctx, def.source_item_id)
+
+        macro_rules! def {
+            ($kind:ident, $ast_id:ident) => {
+                $kind { id: AstItemDef::from_ast_id(ctx, $ast_id) }.into()
             };
         }
         let name = def.name.clone();
         let def: PerNs<ModuleDef> = match def.kind {
-            raw::DefKind::Function => PerNs::values(Function { id: id!() }.into()),
-            raw::DefKind::Struct => {
-                let s = Struct { id: id!() }.into();
+            raw::DefKind::Function(ast_id) => PerNs::values(def!(Function, ast_id)),
+            raw::DefKind::Struct(ast_id) => {
+                let s = def!(Struct, ast_id);
                 PerNs::both(s, s)
             }
-            raw::DefKind::Enum => PerNs::types(Enum { id: id!() }.into()),
-            raw::DefKind::Const => PerNs::values(Const { id: id!() }.into()),
-            raw::DefKind::Static => PerNs::values(Static { id: id!() }.into()),
-            raw::DefKind::Trait => PerNs::types(Trait { id: id!() }.into()),
-            raw::DefKind::TypeAlias => PerNs::types(TypeAlias { id: id!() }.into()),
+            raw::DefKind::Enum(ast_id) => PerNs::types(def!(Enum, ast_id)),
+            raw::DefKind::Const(ast_id) => PerNs::values(def!(Const, ast_id)),
+            raw::DefKind::Static(ast_id) => PerNs::values(def!(Static, ast_id)),
+            raw::DefKind::Trait(ast_id) => PerNs::types(def!(Trait, ast_id)),
+            raw::DefKind::TypeAlias(ast_id) => PerNs::types(def!(TypeAlias, ast_id)),
         };
         let resolution = Resolution { def, import: None };
         self.def_collector.update(self.module_id, None, &[(name, resolution)])
@@ -484,39 +456,27 @@ where
         // Case 1: macro rules, define a macro in crate-global mutable scope
         if is_macro_rules(&mac.path) {
             if let Some(name) = &mac.name {
-                self.def_collector.define_macro(name.clone(), &mac.arg, mac.export)
+                let macro_id = MacroDefId(mac.ast_id.with_file_id(self.file_id));
+                self.def_collector.define_macro(name.clone(), macro_id, mac.export)
             }
             return;
         }
 
-        let source_item_id = SourceItemId { file_id: self.file_id, item_id: mac.source_item_id };
-        let macro_call_id = MacroCallLoc {
-            module: Module { krate: self.def_collector.def_map.krate, module_id: self.module_id },
-            source_item_id,
-        }
-        .id(self.def_collector.db);
+        let ast_id = mac.ast_id.with_file_id(self.file_id);
 
         // Case 2: try to expand macro_rules from this crate, triggering
         // recursive item collection.
         if let Some(&macro_id) =
             mac.path.as_ident().and_then(|name| self.def_collector.global_macro_scope.get(name))
         {
-            self.def_collector.collect_macro_expansion(
-                self.module_id,
-                macro_call_id,
-                (self.def_collector.def_map.krate, macro_id),
-                mac.arg.clone(),
-            );
+            let macro_call_id = MacroCallLoc { def: macro_id, ast_id }.id(self.def_collector.db);
+
+            self.def_collector.collect_macro_expansion(self.module_id, macro_call_id);
             return;
         }
 
         // Case 3: path to a macro from another crate, expand during name resolution
-        self.def_collector.unexpanded_macros.push((
-            self.module_id,
-            macro_call_id,
-            mac.path.clone(),
-            mac.arg.clone(),
-        ))
+        self.def_collector.unexpanded_macros.push((self.module_id, ast_id, mac.path.clone()))
     }
 }
 
diff --git a/crates/ra_hir/src/nameres/raw.rs b/crates/ra_hir/src/nameres/raw.rs
index f8ba398ec..0936229ac 100644
--- a/crates/ra_hir/src/nameres/raw.rs
+++ b/crates/ra_hir/src/nameres/raw.rs
@@ -4,7 +4,6 @@ use std::{
 };
 
 use test_utils::tested_by;
-use ra_db::FileId;
 use ra_arena::{Arena, impl_arena_id, RawId, map::ArenaMap};
 use ra_syntax::{
     AstNode, SourceFile, AstPtr, TreeArc,
@@ -13,9 +12,13 @@ use ra_syntax::{
 
 use crate::{
     DefDatabase, Name, AsName, Path, HirFileId, ModuleSource,
-    ids::{SourceFileItemId, SourceFileItems},
+    AstIdMap, FileAstId,
 };
 
+/// `RawItems` is a set of top-level items in a file (except for impls).
+///
+/// It is the input to name resolution algorithm. `RawItems` are not invalidated
+/// on most edits.
 #[derive(Debug, Default, PartialEq, Eq)]
 pub struct RawItems {
     modules: Arena<Module, ModuleData>,
@@ -32,11 +35,11 @@ pub struct ImportSourceMap {
 }
 
 impl ImportSourceMap {
-    pub(crate) fn insert(&mut self, import: ImportId, segment: &ast::PathSegment) {
+    fn insert(&mut self, import: ImportId, segment: &ast::PathSegment) {
         self.map.insert(import, AstPtr::new(segment))
     }
 
-    pub fn get(&self, source: &ModuleSource, import: ImportId) -> TreeArc<ast::PathSegment> {
+    pub(crate) fn get(&self, source: &ModuleSource, import: ImportId) -> TreeArc<ast::PathSegment> {
         let file = match source {
             ModuleSource::SourceFile(file) => &*file,
             ModuleSource::Module(m) => m.syntax().ancestors().find_map(SourceFile::cast).unwrap(),
@@ -47,40 +50,27 @@ impl ImportSourceMap {
 }
 
 impl RawItems {
-    pub(crate) fn raw_items_query(db: &impl DefDatabase, file_id: FileId) -> Arc<RawItems> {
+    pub(crate) fn raw_items_query(db: &impl DefDatabase, file_id: HirFileId) -> Arc<RawItems> {
         db.raw_items_with_source_map(file_id).0
     }
 
     pub(crate) fn raw_items_with_source_map_query(
         db: &impl DefDatabase,
-        file_id: FileId,
+        file_id: HirFileId,
     ) -> (Arc<RawItems>, Arc<ImportSourceMap>) {
         let mut collector = RawItemsCollector {
             raw_items: RawItems::default(),
-            source_file_items: db.file_items(file_id.into()),
+            source_ast_id_map: db.ast_id_map(file_id.into()),
             source_map: ImportSourceMap::default(),
         };
-        let source_file = db.parse(file_id);
+        let source_file = db.hir_parse(file_id);
         collector.process_module(None, &*source_file);
         (Arc::new(collector.raw_items), Arc::new(collector.source_map))
     }
 
-    pub(crate) fn items(&self) -> &[RawItem] {
+    pub(super) fn items(&self) -> &[RawItem] {
         &self.items
     }
-
-    // We can't use queries during name resolution for fear of cycles, so this
-    // is a query-less variant of the above function.
-    pub(crate) fn from_source_file(source_file: &SourceFile, file_id: HirFileId) -> RawItems {
-        let source_file_items = SourceFileItems::from_source_file(source_file, file_id);
-        let mut collector = RawItemsCollector {
-            raw_items: RawItems::default(),
-            source_file_items: Arc::new(source_file_items),
-            source_map: ImportSourceMap::default(),
-        };
-        collector.process_module(None, &*source_file);
-        collector.raw_items
-    }
 }
 
 impl Index<Module> for RawItems {
@@ -112,7 +102,7 @@ impl Index<Macro> for RawItems {
 }
 
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
-pub(crate) enum RawItem {
+pub(super) enum RawItem {
     Module(Module),
     Import(ImportId),
     Def(Def),
@@ -120,13 +110,13 @@ pub(crate) enum RawItem {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub(crate) struct Module(RawId);
+pub(super) struct Module(RawId);
 impl_arena_id!(Module);
 
 #[derive(Debug, PartialEq, Eq)]
-pub(crate) enum ModuleData {
-    Declaration { name: Name, source_item_id: SourceFileItemId },
-    Definition { name: Name, source_item_id: SourceFileItemId, items: Vec<RawItem> },
+pub(super) enum ModuleData {
+    Declaration { name: Name, ast_id: FileAstId<ast::Module> },
+    Definition { name: Name, ast_id: FileAstId<ast::Module>, items: Vec<RawItem> },
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -135,51 +125,49 @@ impl_arena_id!(ImportId);
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ImportData {
-    pub(crate) path: Path,
-    pub(crate) alias: Option<Name>,
-    pub(crate) is_glob: bool,
-    pub(crate) is_prelude: bool,
-    pub(crate) is_extern_crate: bool,
+    pub(super) path: Path,
+    pub(super) alias: Option<Name>,
+    pub(super) is_glob: bool,
+    pub(super) is_prelude: bool,
+    pub(super) is_extern_crate: bool,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub(crate) struct Def(RawId);
+pub(super) struct Def(RawId);
 impl_arena_id!(Def);
 
 #[derive(Debug, PartialEq, Eq)]
-pub(crate) struct DefData {
-    pub(crate) source_item_id: SourceFileItemId,
-    pub(crate) name: Name,
-    pub(crate) kind: DefKind,
+pub(super) struct DefData {
+    pub(super) name: Name,
+    pub(super) kind: DefKind,
 }
 
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
-pub(crate) enum DefKind {
-    Function,
-    Struct,
-    Enum,
-    Const,
-    Static,
-    Trait,
-    TypeAlias,
+pub(super) enum DefKind {
+    Function(FileAstId<ast::FnDef>),
+    Struct(FileAstId<ast::StructDef>),
+    Enum(FileAstId<ast::EnumDef>),
+    Const(FileAstId<ast::ConstDef>),
+    Static(FileAstId<ast::StaticDef>),
+    Trait(FileAstId<ast::TraitDef>),
+    TypeAlias(FileAstId<ast::TypeAliasDef>),
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub(crate) struct Macro(RawId);
+pub(super) struct Macro(RawId);
 impl_arena_id!(Macro);
 
 #[derive(Debug, PartialEq, Eq)]
-pub(crate) struct MacroData {
-    pub(crate) source_item_id: SourceFileItemId,
-    pub(crate) path: Path,
-    pub(crate) name: Option<Name>,
-    pub(crate) arg: tt::Subtree,
-    pub(crate) export: bool,
+pub(super) struct MacroData {
+    pub(super) ast_id: FileAstId<ast::MacroCall>,
+    pub(super) path: Path,
+    pub(super) name: Option<Name>,
+    pub(super) export: bool,
 }
 
 struct RawItemsCollector {
     raw_items: RawItems,
-    source_file_items: Arc<SourceFileItems>,
+    source_ast_id_map: Arc<AstIdMap>,
     source_map: ImportSourceMap,
 }
 
@@ -211,18 +199,31 @@ impl RawItemsCollector {
                 // impls don't participate in name resolution
                 return;
             }
-            ast::ModuleItemKind::StructDef(it) => (DefKind::Struct, it.name()),
-            ast::ModuleItemKind::EnumDef(it) => (DefKind::Enum, it.name()),
-            ast::ModuleItemKind::FnDef(it) => (DefKind::Function, it.name()),
-            ast::ModuleItemKind::TraitDef(it) => (DefKind::Trait, it.name()),
-            ast::ModuleItemKind::TypeAliasDef(it) => (DefKind::TypeAlias, it.name()),
-            ast::ModuleItemKind::ConstDef(it) => (DefKind::Const, it.name()),
-            ast::ModuleItemKind::StaticDef(it) => (DefKind::Static, it.name()),
+            ast::ModuleItemKind::StructDef(it) => {
+                (DefKind::Struct(self.source_ast_id_map.ast_id(it)), it.name())
+            }
+            ast::ModuleItemKind::EnumDef(it) => {
+                (DefKind::Enum(self.source_ast_id_map.ast_id(it)), it.name())
+            }
+            ast::ModuleItemKind::FnDef(it) => {
+                (DefKind::Function(self.source_ast_id_map.ast_id(it)), it.name())
+            }
+            ast::ModuleItemKind::TraitDef(it) => {
+                (DefKind::Trait(self.source_ast_id_map.ast_id(it)), it.name())
+            }
+            ast::ModuleItemKind::TypeAliasDef(it) => {
+                (DefKind::TypeAlias(self.source_ast_id_map.ast_id(it)), it.name())
+            }
+            ast::ModuleItemKind::ConstDef(it) => {
+                (DefKind::Const(self.source_ast_id_map.ast_id(it)), it.name())
+            }
+            ast::ModuleItemKind::StaticDef(it) => {
+                (DefKind::Static(self.source_ast_id_map.ast_id(it)), it.name())
+            }
         };
         if let Some(name) = name {
             let name = name.as_name();
-            let source_item_id = self.source_file_items.id_of_unchecked(item.syntax());
-            let def = self.raw_items.defs.alloc(DefData { name, kind, source_item_id });
+            let def = self.raw_items.defs.alloc(DefData { name, kind });
             self.push_item(current_module, RawItem::Def(def))
         }
     }
@@ -232,10 +233,9 @@ impl RawItemsCollector {
             Some(it) => it.as_name(),
             None => return,
         };
-        let source_item_id = self.source_file_items.id_of_unchecked(module.syntax());
+        let ast_id = self.source_ast_id_map.ast_id(module);
         if module.has_semi() {
-            let item =
-                self.raw_items.modules.alloc(ModuleData::Declaration { name, source_item_id });
+            let item = self.raw_items.modules.alloc(ModuleData::Declaration { name, ast_id });
             self.push_item(current_module, RawItem::Module(item));
             return;
         }
@@ -243,7 +243,7 @@ impl RawItemsCollector {
         if let Some(item_list) = module.item_list() {
             let item = self.raw_items.modules.alloc(ModuleData::Definition {
                 name,
-                source_item_id,
+                ast_id,
                 items: Vec::new(),
             });
             self.process_module(Some(item), item_list);
@@ -291,18 +291,15 @@ impl RawItemsCollector {
     }
 
     fn add_macro(&mut self, current_module: Option<Module>, m: &ast::MacroCall) {
-        let (path, arg) = match (
-            m.path().and_then(Path::from_ast),
-            m.token_tree().and_then(mbe::ast_to_token_tree),
-        ) {
-            (Some(path), Some((token_tree, _token_map))) => (path, token_tree),
+        let path = match m.path().and_then(Path::from_ast) {
+            Some(it) => it,
             _ => return,
         };
 
         let name = m.name().map(|it| it.as_name());
-        let source_item_id = self.source_file_items.id_of_unchecked(m.syntax());
+        let ast_id = self.source_ast_id_map.ast_id(m);
         let export = m.has_atom_attr("macro_export");
-        let m = self.raw_items.macros.alloc(MacroData { source_item_id, path, arg, name, export });
+        let m = self.raw_items.macros.alloc(MacroData { ast_id, path, name, export });
         self.push_item(current_module, RawItem::Macro(m));
     }
 
diff --git a/crates/ra_hir/src/nameres/tests/incremental.rs b/crates/ra_hir/src/nameres/tests/incremental.rs
index 698781923..001f76ac3 100644
--- a/crates/ra_hir/src/nameres/tests/incremental.rs
+++ b/crates/ra_hir/src/nameres/tests/incremental.rs
@@ -90,34 +90,44 @@ fn adding_inner_items_should_not_invalidate_def_map() {
     );
 }
 
-// It would be awesome to make this work, but it's unclear how
 #[test]
-#[ignore]
-fn typing_inside_a_function_inside_a_macro_should_not_invalidate_def_map() {
-    check_def_map_is_not_recomputed(
+fn typing_inside_a_macro_should_not_invalidate_def_map() {
+    let (mut db, pos) = MockDatabase::with_position(
         "
         //- /lib.rs
+        macro_rules! m {
+            ($ident:ident) => {
+                fn f() {
+                    $ident + $ident;
+                };
+            }
+        }
         mod foo;
 
-        use crate::foo::bar::Baz;
-
         //- /foo/mod.rs
         pub mod bar;
 
         //- /foo/bar.rs
         <|>
-        salsa::query_group! {
-            trait Baz {
-                fn foo() -> i32 { 1 + 1 }
-            }
-        }
-        ",
-        "
-        salsa::query_group! {
-            trait Baz {
-                fn foo() -> i32 { 92 }
-            }
-        }
+        m!(X);
         ",
     );
+    {
+        let events = db.log_executed(|| {
+            let module = crate::source_binder::module_from_file_id(&db, pos.file_id).unwrap();
+            let decls = module.declarations(&db);
+            assert_eq!(decls.len(), 1);
+        });
+        assert!(format!("{:?}", events).contains("crate_def_map"), "{:#?}", events)
+    }
+    db.set_file_text(pos.file_id, Arc::new("m!(Y);".to_string()));
+
+    {
+        let events = db.log_executed(|| {
+            let module = crate::source_binder::module_from_file_id(&db, pos.file_id).unwrap();
+            let decls = module.declarations(&db);
+            assert_eq!(decls.len(), 1);
+        });
+        assert!(!format!("{:?}", events).contains("crate_def_map"), "{:#?}", events)
+    }
 }
diff --git a/crates/ra_hir/src/resolve.rs b/crates/ra_hir/src/resolve.rs
index f28154517..2609585b1 100644
--- a/crates/ra_hir/src/resolve.rs
+++ b/crates/ra_hir/src/resolve.rs
@@ -11,7 +11,7 @@ use crate::{
     generics::GenericParams,
     expr::{scope::{ExprScopes, ScopeId}, PatId, Body},
     impl_block::ImplBlock,
-    path::Path,
+    path::Path, Trait
 };
 
 #[derive(Debug, Clone, Default)]
@@ -175,6 +175,21 @@ impl Resolver {
         names
     }
 
+    pub(crate) fn traits_in_scope<'a>(&'a self) -> impl Iterator<Item = Trait> + 'a {
+        // FIXME prelude
+        self.scopes
+            .iter()
+            .rev()
+            .flat_map(|scope| {
+                match scope {
+                    Scope::ModuleScope(m) => Some(m.crate_def_map[m.module_id].scope.traits()),
+                    _ => None,
+                }
+                .into_iter()
+            })
+            .flatten()
+    }
+
     fn module(&self) -> Option<(&CrateDefMap, CrateModuleId)> {
         self.scopes.iter().rev().find_map(|scope| match scope {
             Scope::ModuleScope(m) => Some((&*m.crate_def_map, m.module_id)),
diff --git a/crates/ra_hir/src/source_binder.rs b/crates/ra_hir/src/source_binder.rs
index 3645b73b4..9dae4c3d1 100644
--- a/crates/ra_hir/src/source_binder.rs
+++ b/crates/ra_hir/src/source_binder.rs
@@ -15,8 +15,8 @@ use ra_syntax::{
 use crate::{
     HirDatabase, Function, Struct, Enum,
     AsName, Module, HirFileId, Crate, Trait, Resolver,
-    ids::{LocationCtx, SourceFileItemId},
-    expr
+    ids::LocationCtx,
+    expr, AstId
 };
 
 /// Locates the module by `FileId`. Picks topmost module in the file.
@@ -54,8 +54,8 @@ fn module_from_inline(
 ) -> Option<Module> {
     assert!(!module.has_semi());
     let file_id = file_id.into();
-    let file_items = db.file_items(file_id);
-    let item_id = file_items.id_of(file_id, module.syntax());
+    let ast_id_map = db.ast_id_map(file_id);
+    let item_id = ast_id_map.ast_id(module).with_file_id(file_id);
     module_from_source(db, file_id, Some(item_id))
 }
 
@@ -75,7 +75,7 @@ pub fn module_from_child_node(
 fn module_from_source(
     db: &impl HirDatabase,
     file_id: HirFileId,
-    decl_id: Option<SourceFileItemId>,
+    decl_id: Option<AstId<ast::Module>>,
 ) -> Option<Module> {
     let source_root_id = db.file_source_root(file_id.as_original_file());
     db.source_root_crates(source_root_id).iter().map(|&crate_id| Crate { crate_id }).find_map(
diff --git a/crates/ra_hir/src/source_id.rs b/crates/ra_hir/src/source_id.rs
new file mode 100644
index 000000000..0a8fb6d32
--- /dev/null
+++ b/crates/ra_hir/src/source_id.rs
@@ -0,0 +1,150 @@
+use std::{marker::PhantomData, sync::Arc, hash::{Hash, Hasher}};
+
+use ra_arena::{Arena, RawId, impl_arena_id};
+use ra_syntax::{SyntaxNodePtr, TreeArc, SyntaxNode, SourceFile, AstNode, ast};
+
+use crate::{HirFileId, DefDatabase};
+
+/// `AstId` points to an AST node in any file.
+///
+/// It is stable across reparses, and can be used as salsa key/value.
+#[derive(Debug)]
+pub(crate) struct AstId<N: AstNode> {
+    file_id: HirFileId,
+    file_ast_id: FileAstId<N>,
+}
+
+impl<N: AstNode> Clone for AstId<N> {
+    fn clone(&self) -> AstId<N> {
+        *self
+    }
+}
+impl<N: AstNode> Copy for AstId<N> {}
+
+impl<N: AstNode> PartialEq for AstId<N> {
+    fn eq(&self, other: &Self) -> bool {
+        (self.file_id, self.file_ast_id) == (other.file_id, other.file_ast_id)
+    }
+}
+impl<N: AstNode> Eq for AstId<N> {}
+impl<N: AstNode> Hash for AstId<N> {
+    fn hash<H: Hasher>(&self, hasher: &mut H) {
+        (self.file_id, self.file_ast_id).hash(hasher);
+    }
+}
+
+impl<N: AstNode> AstId<N> {
+    pub(crate) fn file_id(&self) -> HirFileId {
+        self.file_id
+    }
+
+    pub(crate) fn to_node(&self, db: &impl DefDatabase) -> TreeArc<N> {
+        let syntax_node = db.ast_id_to_node(self.file_id, self.file_ast_id.raw);
+        N::cast(&syntax_node).unwrap().to_owned()
+    }
+}
+
+/// `AstId` points to an AST node in a specific file.
+#[derive(Debug)]
+pub(crate) struct FileAstId<N: AstNode> {
+    raw: ErasedFileAstId,
+    _ty: PhantomData<N>,
+}
+
+impl<N: AstNode> Clone for FileAstId<N> {
+    fn clone(&self) -> FileAstId<N> {
+        *self
+    }
+}
+impl<N: AstNode> Copy for FileAstId<N> {}
+
+impl<N: AstNode> PartialEq for FileAstId<N> {
+    fn eq(&self, other: &Self) -> bool {
+        self.raw == other.raw
+    }
+}
+impl<N: AstNode> Eq for FileAstId<N> {}
+impl<N: AstNode> Hash for FileAstId<N> {
+    fn hash<H: Hasher>(&self, hasher: &mut H) {
+        self.raw.hash(hasher);
+    }
+}
+
+impl<N: AstNode> FileAstId<N> {
+    pub(crate) fn with_file_id(self, file_id: HirFileId) -> AstId<N> {
+        AstId { file_id, file_ast_id: self }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct ErasedFileAstId(RawId);
+impl_arena_id!(ErasedFileAstId);
+
+/// Maps items' `SyntaxNode`s to `ErasedFileAstId`s and back.
+#[derive(Debug, PartialEq, Eq)]
+pub struct AstIdMap {
+    arena: Arena<ErasedFileAstId, SyntaxNodePtr>,
+}
+
+impl AstIdMap {
+    pub(crate) fn ast_id_map_query(db: &impl DefDatabase, file_id: HirFileId) -> Arc<AstIdMap> {
+        let source_file = db.hir_parse(file_id);
+        Arc::new(AstIdMap::from_source_file(&source_file))
+    }
+
+    pub(crate) fn file_item_query(
+        db: &impl DefDatabase,
+        file_id: HirFileId,
+        ast_id: ErasedFileAstId,
+    ) -> TreeArc<SyntaxNode> {
+        let source_file = db.hir_parse(file_id);
+        db.ast_id_map(file_id).arena[ast_id].to_node(&source_file).to_owned()
+    }
+
+    pub(crate) fn ast_id<N: AstNode>(&self, item: &N) -> FileAstId<N> {
+        let ptr = SyntaxNodePtr::new(item.syntax());
+        let raw = match self.arena.iter().find(|(_id, i)| **i == ptr) {
+            Some((it, _)) => it,
+            None => panic!(
+                "Can't find {:?} in AstIdMap:\n{:?}",
+                item.syntax(),
+                self.arena.iter().map(|(_id, i)| i).collect::<Vec<_>>(),
+            ),
+        };
+
+        FileAstId { raw, _ty: PhantomData }
+    }
+
+    fn from_source_file(source_file: &SourceFile) -> AstIdMap {
+        let mut res = AstIdMap { arena: Arena::default() };
+        // By walking the tree in bread-first order we make sure that parents
+        // get lower ids then children. That is, adding a new child does not
+        // change parent's id. This means that, say, adding a new function to a
+        // trait does not change ids of top-level items, which helps caching.
+        bfs(source_file.syntax(), |it| {
+            if let Some(module_item) = ast::ModuleItem::cast(it) {
+                res.alloc(module_item.syntax());
+            } else if let Some(macro_call) = ast::MacroCall::cast(it) {
+                res.alloc(macro_call.syntax());
+            }
+        });
+        res
+    }
+
+    fn alloc(&mut self, item: &SyntaxNode) -> ErasedFileAstId {
+        self.arena.alloc(SyntaxNodePtr::new(item))
+    }
+}
+
+/// Walks the subtree in bfs order, calling `f` for each node.
+fn bfs(node: &SyntaxNode, mut f: impl FnMut(&SyntaxNode)) {
+    let mut curr_layer = vec![node];
+    let mut next_layer = vec![];
+    while !curr_layer.is_empty() {
+        curr_layer.drain(..).for_each(|node| {
+            next_layer.extend(node.children());
+            f(node);
+        });
+        std::mem::swap(&mut curr_layer, &mut next_layer);
+    }
+}
diff --git a/crates/ra_hir/src/traits.rs b/crates/ra_hir/src/traits.rs
new file mode 100644
index 000000000..725bdd5cb
--- /dev/null
+++ b/crates/ra_hir/src/traits.rs
@@ -0,0 +1,52 @@
+//! HIR for trait definitions.
+
+use std::sync::Arc;
+
+use ra_syntax::ast::{self, NameOwner};
+
+use crate::{Function, Const, TypeAlias, Name, DefDatabase, Trait, ids::LocationCtx, name::AsName};
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct TraitData {
+    name: Option<Name>,
+    items: Vec<TraitItem>,
+}
+
+impl TraitData {
+    pub(crate) fn trait_data_query(db: &impl DefDatabase, tr: Trait) -> Arc<TraitData> {
+        let (file_id, node) = tr.source(db);
+        let name = node.name().map(|n| n.as_name());
+        let module = tr.module(db);
+        let ctx = LocationCtx::new(db, module, file_id);
+        let items = if let Some(item_list) = node.item_list() {
+            item_list
+                .impl_items()
+                .map(|item_node| match item_node.kind() {
+                    ast::ImplItemKind::FnDef(it) => Function { id: ctx.to_def(it) }.into(),
+                    ast::ImplItemKind::ConstDef(it) => Const { id: ctx.to_def(it) }.into(),
+                    ast::ImplItemKind::TypeAliasDef(it) => TypeAlias { id: ctx.to_def(it) }.into(),
+                })
+                .collect()
+        } else {
+            Vec::new()
+        };
+        Arc::new(TraitData { name, items })
+    }
+
+    pub(crate) fn name(&self) -> &Option<Name> {
+        &self.name
+    }
+
+    pub(crate) fn items(&self) -> &[TraitItem] {
+        &self.items
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum TraitItem {
+    Function(Function),
+    Const(Const),
+    TypeAlias(TypeAlias),
+    // Existential
+}
+impl_froms!(TraitItem: Function, Const, TypeAlias);
diff --git a/crates/ra_hir/src/ty.rs b/crates/ra_hir/src/ty.rs
index 7d25ade47..d42c61e9d 100644
--- a/crates/ra_hir/src/ty.rs
+++ b/crates/ra_hir/src/ty.rs
@@ -14,7 +14,7 @@ pub(crate) mod display;
 use std::sync::Arc;
 use std::{fmt, mem};
 
-use crate::{Name, AdtDef, type_ref::Mutability, db::HirDatabase};
+use crate::{Name, AdtDef, type_ref::Mutability, db::HirDatabase, Trait};
 
 pub(crate) use lower::{TypableDef, CallableDef, type_for_def, type_for_field, callable_item_sig};
 pub(crate) use infer::{infer, InferenceResult, InferTy};
@@ -91,7 +91,7 @@ pub enum TypeCtor {
 /// A nominal type with (maybe 0) type parameters. This might be a primitive
 /// type like `bool`, a struct, tuple, function pointer, reference or
 /// several other things.
-#[derive(Clone, PartialEq, Eq, Debug)]
+#[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub struct ApplicationTy {
     pub ctor: TypeCtor,
     pub parameters: Substs,
@@ -103,7 +103,7 @@ pub struct ApplicationTy {
 /// the same thing (but in a different way).
 ///
 /// This should be cheap to clone.
-#[derive(Clone, PartialEq, Eq, Debug)]
+#[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub enum Ty {
     /// A nominal type with (maybe 0) type parameters. This might be a primitive
     /// type like `bool`, a struct, tuple, function pointer, reference or
@@ -132,7 +132,7 @@ pub enum Ty {
 }
 
 /// A list of substitutions for generic parameters.
-#[derive(Clone, PartialEq, Eq, Debug)]
+#[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub struct Substs(Arc<[Ty]>);
 
 impl Substs {
@@ -169,6 +169,21 @@ impl Substs {
     }
 }
 
+/// A trait with type parameters. This includes the `Self`, so this represents a concrete type implementing the trait.
+/// Name to be bikeshedded: TraitBound? TraitImplements?
+#[derive(Clone, PartialEq, Eq, Debug, Hash)]
+pub struct TraitRef {
+    /// FIXME name?
+    trait_: Trait,
+    substs: Substs,
+}
+
+impl TraitRef {
+    pub fn self_ty(&self) -> &Ty {
+        &self.substs.0[0]
+    }
+}
+
 /// A function signature as seen by type inference: Several parameter types and
 /// one return type.
 #[derive(Clone, PartialEq, Eq, Debug)]
diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index 5fd602a9e..573115321 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -821,7 +821,8 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             }
             Expr::MethodCall { receiver, args, method_name, generic_args } => {
                 let receiver_ty = self.infer_expr(*receiver, &Expectation::none());
-                let resolved = receiver_ty.clone().lookup_method(self.db, method_name);
+                let resolved =
+                    receiver_ty.clone().lookup_method(self.db, method_name, &self.resolver);
                 let (derefed_receiver_ty, method_ty, def_generics) = match resolved {
                     Some((ty, func)) => {
                         self.write_method_resolution(tgt_expr, func);
diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs
index b1684acf9..3ac8dc46b 100644
--- a/crates/ra_hir/src/ty/method_resolution.rs
+++ b/crates/ra_hir/src/ty/method_resolution.rs
@@ -8,12 +8,12 @@ use rustc_hash::FxHashMap;
 
 use crate::{
     HirDatabase, Module, Crate, Name, Function, Trait,
-    ids::TraitId,
     impl_block::{ImplId, ImplBlock, ImplItem},
     ty::{Ty, TypeCtor},
-    nameres::CrateModuleId,
+    nameres::CrateModuleId, resolve::Resolver, traits::TraitItem
 
 };
+use super::{ TraitRef, Substs};
 
 /// This is used as a key for indexing impls.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
@@ -38,7 +38,7 @@ pub struct CrateImplBlocks {
     /// To make sense of the CrateModuleIds, we need the source root.
     krate: Crate,
     impls: FxHashMap<TyFingerprint, Vec<(CrateModuleId, ImplId)>>,
-    impls_by_trait: FxHashMap<TraitId, Vec<(CrateModuleId, ImplId)>>,
+    impls_by_trait: FxHashMap<Trait, Vec<(CrateModuleId, ImplId)>>,
 }
 
 impl CrateImplBlocks {
@@ -56,8 +56,7 @@ impl CrateImplBlocks {
         &'a self,
         tr: &Trait,
     ) -> impl Iterator<Item = ImplBlock> + 'a {
-        let id = tr.id;
-        self.impls_by_trait.get(&id).into_iter().flat_map(|i| i.iter()).map(
+        self.impls_by_trait.get(&tr).into_iter().flat_map(|i| i.iter()).map(
             move |(module_id, impl_id)| {
                 let module = Module { krate: self.krate, module_id: *module_id };
                 ImplBlock::from_id(module, *impl_id)
@@ -73,18 +72,18 @@ impl CrateImplBlocks {
 
             let target_ty = impl_block.target_ty(db);
 
-            if let Some(target_ty_fp) = TyFingerprint::for_impl(&target_ty) {
-                self.impls
-                    .entry(target_ty_fp)
-                    .or_insert_with(Vec::new)
-                    .push((module.module_id, impl_id));
-            }
-
             if let Some(tr) = impl_block.target_trait(db) {
                 self.impls_by_trait
-                    .entry(tr.id)
+                    .entry(tr)
                     .or_insert_with(Vec::new)
                     .push((module.module_id, impl_id));
+            } else {
+                if let Some(target_ty_fp) = TyFingerprint::for_impl(&target_ty) {
+                    self.impls
+                        .entry(target_ty_fp)
+                        .or_insert_with(Vec::new)
+                        .push((module.module_id, impl_id));
+                }
             }
         }
 
@@ -109,6 +108,20 @@ impl CrateImplBlocks {
     }
 }
 
+/// Rudimentary check whether an impl exists for a given type and trait; this
+/// will actually be done by chalk.
+pub(crate) fn implements(db: &impl HirDatabase, trait_ref: TraitRef) -> bool {
+    // FIXME use all trait impls in the whole crate graph
+    let krate = trait_ref.trait_.module(db).krate(db);
+    let krate = match krate {
+        Some(krate) => krate,
+        None => return false,
+    };
+    let crate_impl_blocks = db.impls_in_crate(krate);
+    let mut impl_blocks = crate_impl_blocks.lookup_impl_blocks_for_trait(&trait_ref.trait_);
+    impl_blocks.any(|impl_block| &impl_block.target_ty(db) == trait_ref.self_ty())
+}
+
 fn def_crate(db: &impl HirDatabase, ty: &Ty) -> Option<Crate> {
     match ty {
         Ty::Apply(a_ty) => match a_ty.ctor {
@@ -120,20 +133,64 @@ fn def_crate(db: &impl HirDatabase, ty: &Ty) -> Option<Crate> {
 }
 
 impl Ty {
-    // FIXME: cache this as a query?
-    // - if so, what signature? (TyFingerprint, Name)?
-    // - or maybe cache all names and def_ids of methods per fingerprint?
     /// Look up the method with the given name, returning the actual autoderefed
     /// receiver type (but without autoref applied yet).
-    pub fn lookup_method(self, db: &impl HirDatabase, name: &Name) -> Option<(Ty, Function)> {
-        self.iterate_methods(db, |ty, f| {
+    pub fn lookup_method(
+        self,
+        db: &impl HirDatabase,
+        name: &Name,
+        resolver: &Resolver,
+    ) -> Option<(Ty, Function)> {
+        // FIXME: trait methods should be used before autoderefs
+        let inherent_method = self.clone().iterate_methods(db, |ty, f| {
             let sig = f.signature(db);
             if sig.name() == name && sig.has_self_param() {
                 Some((ty.clone(), f))
             } else {
                 None
             }
-        })
+        });
+        inherent_method.or_else(|| self.lookup_trait_method(db, name, resolver))
+    }
+
+    fn lookup_trait_method(
+        self,
+        db: &impl HirDatabase,
+        name: &Name,
+        resolver: &Resolver,
+    ) -> Option<(Ty, Function)> {
+        let mut candidates = Vec::new();
+        for t in resolver.traits_in_scope() {
+            let data = t.trait_data(db);
+            for item in data.items() {
+                match item {
+                    &TraitItem::Function(m) => {
+                        let sig = m.signature(db);
+                        if sig.name() == name && sig.has_self_param() {
+                            candidates.push((t, m));
+                        }
+                    }
+                    _ => {}
+                }
+            }
+        }
+        // FIXME:
+        //  - we might not actually be able to determine fully that the type
+        //    implements the trait here; it's enough if we (well, Chalk) determine
+        //    that it's possible.
+        //  - when the trait method is picked, we need to register an
+        //    'obligation' somewhere so that we later check that it's really
+        //    implemented
+        //  - both points go for additional requirements from where clauses as
+        //    well (in fact, the 'implements' condition could just be considered a
+        //    'where Self: Trait' clause)
+        candidates.retain(|(t, _m)| {
+            let trait_ref = TraitRef { trait_: *t, substs: Substs::single(self.clone()) };
+            db.implements(trait_ref)
+        });
+        // FIXME if there's multiple candidates here, that's an ambiguity error
+        let (_chosen_trait, chosen_method) = candidates.first()?;
+        Some((self.clone(), *chosen_method))
     }
 
     // This would be nicer if it just returned an iterator, but that runs into
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index 3aedba243..655f3c522 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -1272,8 +1272,8 @@ fn test() {
 [241; 252) 'Struct::FOO': u32
 [262; 263) 'y': u32
 [266; 275) 'Enum::BAR': u32
-[285; 286) 'z': u32
-[289; 302) 'TraitTest::ID': u32"###
+[285; 286) 'z': {unknown}
+[289; 302) 'TraitTest::ID': {unknown}"###
     );
 }
 
@@ -1918,9 +1918,9 @@ fn test() {
 [110; 114) 'self': &{unknown}
 [170; 228) '{     ...i128 }': ()
 [176; 178) 'S1': S1
-[176; 187) 'S1.method()': {unknown}
+[176; 187) 'S1.method()': u32
 [203; 205) 'S2': S2
-[203; 214) 'S2.method()': {unknown}"###
+[203; 214) 'S2.method()': i128"###
     );
 }
 
@@ -1964,10 +1964,10 @@ mod bar_test {
 [169; 173) 'self': &{unknown}
 [300; 337) '{     ...     }': ()
 [310; 311) 'S': S
-[310; 320) 'S.method()': {unknown}
+[310; 320) 'S.method()': u32
 [416; 454) '{     ...     }': ()
 [426; 427) 'S': S
-[426; 436) 'S.method()': {unknown}"###
+[426; 436) 'S.method()': i128"###
     );
 }
 
diff --git a/crates/ra_ide_api/src/change.rs b/crates/ra_ide_api/src/change.rs
index 26fde91bc..a4a086931 100644
--- a/crates/ra_ide_api/src/change.rs
+++ b/crates/ra_ide_api/src/change.rs
@@ -220,8 +220,8 @@ impl RootDatabase {
         self.query(ra_db::ParseQuery).sweep(sweep);
 
         self.query(hir::db::HirParseQuery).sweep(sweep);
-        self.query(hir::db::FileItemsQuery).sweep(sweep);
-        self.query(hir::db::FileItemQuery).sweep(sweep);
+        self.query(hir::db::AstIdMapQuery).sweep(sweep);
+        self.query(hir::db::AstIdToNodeQuery).sweep(sweep);
 
         self.query(hir::db::RawItemsWithSourceMapQuery).sweep(sweep);
         self.query(hir::db::BodyWithSourceMapQuery).sweep(sweep);
diff --git a/crates/ra_ide_api/src/parent_module.rs b/crates/ra_ide_api/src/parent_module.rs
index 603c3db6a..27788c984 100644
--- a/crates/ra_ide_api/src/parent_module.rs
+++ b/crates/ra_ide_api/src/parent_module.rs
@@ -28,7 +28,11 @@ pub(crate) fn crate_for(db: &RootDatabase, file_id: FileId) -> Vec<CrateId> {
 
 #[cfg(test)]
 mod tests {
-    use crate::mock_analysis::analysis_and_position;
+    use crate::{
+        AnalysisChange, CrateGraph,
+        mock_analysis::{analysis_and_position, MockAnalysis},
+        Edition::Edition2018,
+};
 
     #[test]
     fn test_resolve_parent_module() {
@@ -59,4 +63,28 @@ mod tests {
         let nav = analysis.parent_module(pos).unwrap().pop().unwrap();
         nav.assert_match("baz MODULE FileId(1) [32; 44)");
     }
+
+    #[test]
+    fn test_resolve_crate_root() {
+        let mock = MockAnalysis::with_files(
+            "
+        //- /bar.rs
+        mod foo;
+        //- /foo.rs
+        // empty <|>
+    ",
+        );
+        let root_file = mock.id_of("/bar.rs");
+        let mod_file = mock.id_of("/foo.rs");
+        let mut host = mock.analysis_host();
+        assert!(host.analysis().crate_for(mod_file).unwrap().is_empty());
+
+        let mut crate_graph = CrateGraph::default();
+        let crate_id = crate_graph.add_crate_root(root_file, Edition2018);
+        let mut change = AnalysisChange::new();
+        change.set_crate_graph(crate_graph);
+        host.apply_change(change);
+
+        assert_eq!(host.analysis().crate_for(mod_file).unwrap(), vec![crate_id]);
+    }
 }
diff --git a/crates/ra_ide_api/src/references.rs b/crates/ra_ide_api/src/references.rs
index 22741445a..20bbf11a3 100644
--- a/crates/ra_ide_api/src/references.rs
+++ b/crates/ra_ide_api/src/references.rs
@@ -216,10 +216,56 @@ mod tests {
     use crate::{
         mock_analysis::single_file_with_position,
         mock_analysis::analysis_and_position,
-        FileId
+        FileId, ReferenceSearchResult
 };
 
     #[test]
+    fn test_find_all_refs_for_local() {
+        let code = r#"
+    fn main() {
+        let mut i = 1;
+        let j = 1;
+        i = i<|> + j;
+
+        {
+            i = 0;
+        }
+
+        i = 5;
+    }"#;
+
+        let refs = get_all_refs(code);
+        assert_eq!(refs.len(), 5);
+    }
+
+    #[test]
+    fn test_find_all_refs_for_param_inside() {
+        let code = r#"
+    fn foo(i : u32) -> u32 {
+        i<|>
+    }"#;
+
+        let refs = get_all_refs(code);
+        assert_eq!(refs.len(), 2);
+    }
+
+    #[test]
+    fn test_find_all_refs_for_fn_param() {
+        let code = r#"
+    fn foo(i<|> : u32) -> u32 {
+        i
+    }"#;
+
+        let refs = get_all_refs(code);
+        assert_eq!(refs.len(), 2);
+    }
+
+    fn get_all_refs(text: &str) -> ReferenceSearchResult {
+        let (analysis, position) = single_file_with_position(text);
+        analysis.find_all_refs(position).unwrap().unwrap()
+    }
+
+    #[test]
     fn test_rename_for_local() {
         test_rename(
             r#"
diff --git a/crates/ra_ide_api/src/symbol_index.rs b/crates/ra_ide_api/src/symbol_index.rs
index 0978d164a..0eadc4e71 100644
--- a/crates/ra_ide_api/src/symbol_index.rs
+++ b/crates/ra_ide_api/src/symbol_index.rs
@@ -270,3 +270,61 @@ fn to_file_symbol(node: &SyntaxNode, file_id: FileId) -> Option<FileSymbol> {
         container_name: None,
     })
 }
+
+#[cfg(test)]
+mod tests {
+    use ra_syntax::SmolStr;
+    use crate::{
+        navigation_target::NavigationTarget,
+        mock_analysis::single_file,
+        Query,
+};
+
+    #[test]
+    fn test_world_symbols_with_no_container() {
+        let code = r#"
+    enum FooInner { }
+    "#;
+
+        let mut symbols = get_symbols_matching(code, "FooInner");
+
+        let s = symbols.pop().unwrap();
+
+        assert_eq!(s.name(), "FooInner");
+        assert!(s.container_name().is_none());
+    }
+
+    #[test]
+    fn test_world_symbols_include_container_name() {
+        let code = r#"
+fn foo() {
+    enum FooInner { }
+}
+    "#;
+
+        let mut symbols = get_symbols_matching(code, "FooInner");
+
+        let s = symbols.pop().unwrap();
+
+        assert_eq!(s.name(), "FooInner");
+        assert_eq!(s.container_name(), Some(&SmolStr::new("foo")));
+
+        let code = r#"
+mod foo {
+    struct FooInner;
+}
+    "#;
+
+        let mut symbols = get_symbols_matching(code, "FooInner");
+
+        let s = symbols.pop().unwrap();
+
+        assert_eq!(s.name(), "FooInner");
+        assert_eq!(s.container_name(), Some(&SmolStr::new("foo")));
+    }
+
+    fn get_symbols_matching(text: &str, query: &str) -> Vec<NavigationTarget> {
+        let (analysis, _) = single_file(text);
+        analysis.symbol_search(Query::new(query.into())).unwrap()
+    }
+}
diff --git a/crates/ra_ide_api/src/syntax_tree.rs b/crates/ra_ide_api/src/syntax_tree.rs
index bbe9222b4..276f8a8c8 100644
--- a/crates/ra_ide_api/src/syntax_tree.rs
+++ b/crates/ra_ide_api/src/syntax_tree.rs
@@ -85,3 +85,260 @@ fn syntax_tree_for_token<T: AstToken>(node: &T, text_range: TextRange) -> Option
 

     None

 }

+

+#[cfg(test)]

+mod tests {

+    use crate::mock_analysis::{single_file, single_file_with_range};

+

+    #[test]

+    fn test_syntax_tree_without_range() {

+        // Basic syntax

+        let (analysis, file_id) = single_file(r#"fn foo() {}"#);

+        let syn = analysis.syntax_tree(file_id, None);

+

+        assert_eq!(

+            syn.trim(),

+            r#"

+SOURCE_FILE@[0; 11)

+  FN_DEF@[0; 11)

+    FN_KW@[0; 2)

+    WHITESPACE@[2; 3)

+    NAME@[3; 6)

+      IDENT@[3; 6) "foo"

+    PARAM_LIST@[6; 8)

+      L_PAREN@[6; 7)

+      R_PAREN@[7; 8)

+    WHITESPACE@[8; 9)

+    BLOCK@[9; 11)

+      L_CURLY@[9; 10)

+      R_CURLY@[10; 11)

+    "#

+            .trim()

+        );

+

+        let (analysis, file_id) = single_file(

+            r#"

+fn test() {

+    assert!("

+    fn foo() {

+    }

+    ", "");

+}"#

+            .trim(),

+        );

+        let syn = analysis.syntax_tree(file_id, None);

+

+        assert_eq!(

+            syn.trim(),

+            r#"

+SOURCE_FILE@[0; 60)

+  FN_DEF@[0; 60)

+    FN_KW@[0; 2)

+    WHITESPACE@[2; 3)

+    NAME@[3; 7)

+      IDENT@[3; 7) "test"

+    PARAM_LIST@[7; 9)

+      L_PAREN@[7; 8)

+      R_PAREN@[8; 9)

+    WHITESPACE@[9; 10)

+    BLOCK@[10; 60)

+      L_CURLY@[10; 11)

+      WHITESPACE@[11; 16)

+      EXPR_STMT@[16; 58)

+        MACRO_CALL@[16; 57)

+          PATH@[16; 22)

+            PATH_SEGMENT@[16; 22)

+              NAME_REF@[16; 22)

+                IDENT@[16; 22) "assert"

+          EXCL@[22; 23)

+          TOKEN_TREE@[23; 57)

+            L_PAREN@[23; 24)

+            STRING@[24; 52)

+            COMMA@[52; 53)

+            WHITESPACE@[53; 54)

+            STRING@[54; 56)

+            R_PAREN@[56; 57)

+        SEMI@[57; 58)

+      WHITESPACE@[58; 59)

+      R_CURLY@[59; 60)

+    "#

+            .trim()

+        );

+    }

+

+    #[test]

+    fn test_syntax_tree_with_range() {

+        let (analysis, range) = single_file_with_range(r#"<|>fn foo() {}<|>"#.trim());

+        let syn = analysis.syntax_tree(range.file_id, Some(range.range));

+

+        assert_eq!(

+            syn.trim(),

+            r#"

+FN_DEF@[0; 11)

+  FN_KW@[0; 2)

+  WHITESPACE@[2; 3)

+  NAME@[3; 6)

+    IDENT@[3; 6) "foo"

+  PARAM_LIST@[6; 8)

+    L_PAREN@[6; 7)

+    R_PAREN@[7; 8)

+  WHITESPACE@[8; 9)

+  BLOCK@[9; 11)

+    L_CURLY@[9; 10)

+    R_CURLY@[10; 11)

+    "#

+            .trim()

+        );

+

+        let (analysis, range) = single_file_with_range(

+            r#"fn test() {

+    <|>assert!("

+    fn foo() {

+    }

+    ", "");<|>

+}"#

+            .trim(),

+        );

+        let syn = analysis.syntax_tree(range.file_id, Some(range.range));

+

+        assert_eq!(

+            syn.trim(),

+            r#"

+EXPR_STMT@[16; 58)

+  MACRO_CALL@[16; 57)

+    PATH@[16; 22)

+      PATH_SEGMENT@[16; 22)

+        NAME_REF@[16; 22)

+          IDENT@[16; 22) "assert"

+    EXCL@[22; 23)

+    TOKEN_TREE@[23; 57)

+      L_PAREN@[23; 24)

+      STRING@[24; 52)

+      COMMA@[52; 53)

+      WHITESPACE@[53; 54)

+      STRING@[54; 56)

+      R_PAREN@[56; 57)

+  SEMI@[57; 58)

+    "#

+            .trim()

+        );

+    }

+

+    #[test]

+    fn test_syntax_tree_inside_string() {

+        let (analysis, range) = single_file_with_range(

+            r#"fn test() {

+    assert!("

+<|>fn foo() {

+}<|>

+fn bar() {

+}

+    ", "");

+}"#

+            .trim(),

+        );

+        let syn = analysis.syntax_tree(range.file_id, Some(range.range));

+        assert_eq!(

+            syn.trim(),

+            r#"

+SOURCE_FILE@[0; 12)

+  FN_DEF@[0; 12)

+    FN_KW@[0; 2)

+    WHITESPACE@[2; 3)

+    NAME@[3; 6)

+      IDENT@[3; 6) "foo"

+    PARAM_LIST@[6; 8)

+      L_PAREN@[6; 7)

+      R_PAREN@[7; 8)

+    WHITESPACE@[8; 9)

+    BLOCK@[9; 12)

+      L_CURLY@[9; 10)

+      WHITESPACE@[10; 11)

+      R_CURLY@[11; 12)

+"#

+            .trim()

+        );

+

+        // With a raw string

+        let (analysis, range) = single_file_with_range(

+            r###"fn test() {

+    assert!(r#"

+<|>fn foo() {

+}<|>

+fn bar() {

+}

+    "#, "");

+}"###

+                .trim(),

+        );

+        let syn = analysis.syntax_tree(range.file_id, Some(range.range));

+        assert_eq!(

+            syn.trim(),

+            r#"

+SOURCE_FILE@[0; 12)

+  FN_DEF@[0; 12)

+    FN_KW@[0; 2)

+    WHITESPACE@[2; 3)

+    NAME@[3; 6)

+      IDENT@[3; 6) "foo"

+    PARAM_LIST@[6; 8)

+      L_PAREN@[6; 7)

+      R_PAREN@[7; 8)

+    WHITESPACE@[8; 9)

+    BLOCK@[9; 12)

+      L_CURLY@[9; 10)

+      WHITESPACE@[10; 11)

+      R_CURLY@[11; 12)

+"#

+            .trim()

+        );

+

+        // With a raw string

+        let (analysis, range) = single_file_with_range(

+            r###"fn test() {

+    assert!(r<|>#"

+fn foo() {

+}

+fn bar() {

+}"<|>#, "");

+}"###

+                .trim(),

+        );

+        let syn = analysis.syntax_tree(range.file_id, Some(range.range));

+        assert_eq!(

+            syn.trim(),

+            r#"

+SOURCE_FILE@[0; 25)

+  FN_DEF@[0; 12)

+    FN_KW@[0; 2)

+    WHITESPACE@[2; 3)

+    NAME@[3; 6)

+      IDENT@[3; 6) "foo"

+    PARAM_LIST@[6; 8)

+      L_PAREN@[6; 7)

+      R_PAREN@[7; 8)

+    WHITESPACE@[8; 9)

+    BLOCK@[9; 12)

+      L_CURLY@[9; 10)

+      WHITESPACE@[10; 11)

+      R_CURLY@[11; 12)

+  WHITESPACE@[12; 13)

+  FN_DEF@[13; 25)

+    FN_KW@[13; 15)

+    WHITESPACE@[15; 16)

+    NAME@[16; 19)

+      IDENT@[16; 19) "bar"

+    PARAM_LIST@[19; 21)

+      L_PAREN@[19; 20)

+      R_PAREN@[20; 21)

+    WHITESPACE@[21; 22)

+    BLOCK@[22; 25)

+      L_CURLY@[22; 23)

+      WHITESPACE@[23; 24)

+      R_CURLY@[24; 25)

+

+"#

+            .trim()

+        );

+    }

+}

diff --git a/crates/ra_ide_api/tests/test/main.rs b/crates/ra_ide_api/tests/test/main.rs
deleted file mode 100644
index d4ff21c09..000000000
--- a/crates/ra_ide_api/tests/test/main.rs
+++ /dev/null
@@ -1,376 +0,0 @@
-use ra_ide_api::{
-    mock_analysis::{single_file, single_file_with_position, single_file_with_range, MockAnalysis},
-    AnalysisChange, CrateGraph, Edition::Edition2018, Query, NavigationTarget,
-    ReferenceSearchResult,
-};
-use ra_syntax::SmolStr;
-
-#[test]
-fn test_resolve_crate_root() {
-    let mock = MockAnalysis::with_files(
-        "
-        //- /bar.rs
-        mod foo;
-        //- /foo.rs
-        // empty <|>
-    ",
-    );
-    let root_file = mock.id_of("/bar.rs");
-    let mod_file = mock.id_of("/foo.rs");
-    let mut host = mock.analysis_host();
-    assert!(host.analysis().crate_for(mod_file).unwrap().is_empty());
-
-    let mut crate_graph = CrateGraph::default();
-    let crate_id = crate_graph.add_crate_root(root_file, Edition2018);
-    let mut change = AnalysisChange::new();
-    change.set_crate_graph(crate_graph);
-    host.apply_change(change);
-
-    assert_eq!(host.analysis().crate_for(mod_file).unwrap(), vec![crate_id]);
-}
-
-fn get_all_refs(text: &str) -> ReferenceSearchResult {
-    let (analysis, position) = single_file_with_position(text);
-    analysis.find_all_refs(position).unwrap().unwrap()
-}
-
-fn get_symbols_matching(text: &str, query: &str) -> Vec<NavigationTarget> {
-    let (analysis, _) = single_file(text);
-    analysis.symbol_search(Query::new(query.into())).unwrap()
-}
-
-#[test]
-fn test_find_all_refs_for_local() {
-    let code = r#"
-    fn main() {
-        let mut i = 1;
-        let j = 1;
-        i = i<|> + j;
-
-        {
-            i = 0;
-        }
-
-        i = 5;
-    }"#;
-
-    let refs = get_all_refs(code);
-    assert_eq!(refs.len(), 5);
-}
-
-#[test]
-fn test_find_all_refs_for_param_inside() {
-    let code = r#"
-    fn foo(i : u32) -> u32 {
-        i<|>
-    }"#;
-
-    let refs = get_all_refs(code);
-    assert_eq!(refs.len(), 2);
-}
-
-#[test]
-fn test_find_all_refs_for_fn_param() {
-    let code = r#"
-    fn foo(i<|> : u32) -> u32 {
-        i
-    }"#;
-
-    let refs = get_all_refs(code);
-    assert_eq!(refs.len(), 2);
-}
-
-#[test]
-fn test_world_symbols_with_no_container() {
-    let code = r#"
-    enum FooInner { }
-    "#;
-
-    let mut symbols = get_symbols_matching(code, "FooInner");
-
-    let s = symbols.pop().unwrap();
-
-    assert_eq!(s.name(), "FooInner");
-    assert!(s.container_name().is_none());
-}
-
-#[test]
-fn test_world_symbols_include_container_name() {
-    let code = r#"
-fn foo() {
-    enum FooInner { }
-}
-    "#;
-
-    let mut symbols = get_symbols_matching(code, "FooInner");
-
-    let s = symbols.pop().unwrap();
-
-    assert_eq!(s.name(), "FooInner");
-    assert_eq!(s.container_name(), Some(&SmolStr::new("foo")));
-
-    let code = r#"
-mod foo {
-    struct FooInner;
-}
-    "#;
-
-    let mut symbols = get_symbols_matching(code, "FooInner");
-
-    let s = symbols.pop().unwrap();
-
-    assert_eq!(s.name(), "FooInner");
-    assert_eq!(s.container_name(), Some(&SmolStr::new("foo")));
-}
-
-#[test]
-fn test_syntax_tree_without_range() {
-    // Basic syntax
-    let (analysis, file_id) = single_file(r#"fn foo() {}"#);
-    let syn = analysis.syntax_tree(file_id, None);
-
-    assert_eq!(
-        syn.trim(),
-        r#"
-SOURCE_FILE@[0; 11)
-  FN_DEF@[0; 11)
-    FN_KW@[0; 2)
-    WHITESPACE@[2; 3)
-    NAME@[3; 6)
-      IDENT@[3; 6) "foo"
-    PARAM_LIST@[6; 8)
-      L_PAREN@[6; 7)
-      R_PAREN@[7; 8)
-    WHITESPACE@[8; 9)
-    BLOCK@[9; 11)
-      L_CURLY@[9; 10)
-      R_CURLY@[10; 11)
-    "#
-        .trim()
-    );
-
-    let (analysis, file_id) = single_file(
-        r#"
-fn test() {
-    assert!("
-    fn foo() {
-    }
-    ", "");
-}"#
-        .trim(),
-    );
-    let syn = analysis.syntax_tree(file_id, None);
-
-    assert_eq!(
-        syn.trim(),
-        r#"
-SOURCE_FILE@[0; 60)
-  FN_DEF@[0; 60)
-    FN_KW@[0; 2)
-    WHITESPACE@[2; 3)
-    NAME@[3; 7)
-      IDENT@[3; 7) "test"
-    PARAM_LIST@[7; 9)
-      L_PAREN@[7; 8)
-      R_PAREN@[8; 9)
-    WHITESPACE@[9; 10)
-    BLOCK@[10; 60)
-      L_CURLY@[10; 11)
-      WHITESPACE@[11; 16)
-      EXPR_STMT@[16; 58)
-        MACRO_CALL@[16; 57)
-          PATH@[16; 22)
-            PATH_SEGMENT@[16; 22)
-              NAME_REF@[16; 22)
-                IDENT@[16; 22) "assert"
-          EXCL@[22; 23)
-          TOKEN_TREE@[23; 57)
-            L_PAREN@[23; 24)
-            STRING@[24; 52)
-            COMMA@[52; 53)
-            WHITESPACE@[53; 54)
-            STRING@[54; 56)
-            R_PAREN@[56; 57)
-        SEMI@[57; 58)
-      WHITESPACE@[58; 59)
-      R_CURLY@[59; 60)
-    "#
-        .trim()
-    );
-}
-
-#[test]
-fn test_syntax_tree_with_range() {
-    let (analysis, range) = single_file_with_range(r#"<|>fn foo() {}<|>"#.trim());
-    let syn = analysis.syntax_tree(range.file_id, Some(range.range));
-
-    assert_eq!(
-        syn.trim(),
-        r#"
-FN_DEF@[0; 11)
-  FN_KW@[0; 2)
-  WHITESPACE@[2; 3)
-  NAME@[3; 6)
-    IDENT@[3; 6) "foo"
-  PARAM_LIST@[6; 8)
-    L_PAREN@[6; 7)
-    R_PAREN@[7; 8)
-  WHITESPACE@[8; 9)
-  BLOCK@[9; 11)
-    L_CURLY@[9; 10)
-    R_CURLY@[10; 11)
-    "#
-        .trim()
-    );
-
-    let (analysis, range) = single_file_with_range(
-        r#"fn test() {
-    <|>assert!("
-    fn foo() {
-    }
-    ", "");<|>
-}"#
-        .trim(),
-    );
-    let syn = analysis.syntax_tree(range.file_id, Some(range.range));
-
-    assert_eq!(
-        syn.trim(),
-        r#"
-EXPR_STMT@[16; 58)
-  MACRO_CALL@[16; 57)
-    PATH@[16; 22)
-      PATH_SEGMENT@[16; 22)
-        NAME_REF@[16; 22)
-          IDENT@[16; 22) "assert"
-    EXCL@[22; 23)
-    TOKEN_TREE@[23; 57)
-      L_PAREN@[23; 24)
-      STRING@[24; 52)
-      COMMA@[52; 53)
-      WHITESPACE@[53; 54)
-      STRING@[54; 56)
-      R_PAREN@[56; 57)
-  SEMI@[57; 58)
-    "#
-        .trim()
-    );
-}
-
-#[test]
-fn test_syntax_tree_inside_string() {
-    let (analysis, range) = single_file_with_range(
-        r#"fn test() {
-    assert!("
-<|>fn foo() {
-}<|>
-fn bar() {
-}
-    ", "");
-}"#
-        .trim(),
-    );
-    let syn = analysis.syntax_tree(range.file_id, Some(range.range));
-    assert_eq!(
-        syn.trim(),
-        r#"
-SOURCE_FILE@[0; 12)
-  FN_DEF@[0; 12)
-    FN_KW@[0; 2)
-    WHITESPACE@[2; 3)
-    NAME@[3; 6)
-      IDENT@[3; 6) "foo"
-    PARAM_LIST@[6; 8)
-      L_PAREN@[6; 7)
-      R_PAREN@[7; 8)
-    WHITESPACE@[8; 9)
-    BLOCK@[9; 12)
-      L_CURLY@[9; 10)
-      WHITESPACE@[10; 11)
-      R_CURLY@[11; 12)
-"#
-        .trim()
-    );
-
-    // With a raw string
-    let (analysis, range) = single_file_with_range(
-        r###"fn test() {
-    assert!(r#"
-<|>fn foo() {
-}<|>
-fn bar() {
-}
-    "#, "");
-}"###
-            .trim(),
-    );
-    let syn = analysis.syntax_tree(range.file_id, Some(range.range));
-    assert_eq!(
-        syn.trim(),
-        r#"
-SOURCE_FILE@[0; 12)
-  FN_DEF@[0; 12)
-    FN_KW@[0; 2)
-    WHITESPACE@[2; 3)
-    NAME@[3; 6)
-      IDENT@[3; 6) "foo"
-    PARAM_LIST@[6; 8)
-      L_PAREN@[6; 7)
-      R_PAREN@[7; 8)
-    WHITESPACE@[8; 9)
-    BLOCK@[9; 12)
-      L_CURLY@[9; 10)
-      WHITESPACE@[10; 11)
-      R_CURLY@[11; 12)
-"#
-        .trim()
-    );
-
-    // With a raw string
-    let (analysis, range) = single_file_with_range(
-        r###"fn test() {
-    assert!(r<|>#"
-fn foo() {
-}
-fn bar() {
-}"<|>#, "");
-}"###
-            .trim(),
-    );
-    let syn = analysis.syntax_tree(range.file_id, Some(range.range));
-    assert_eq!(
-        syn.trim(),
-        r#"
-SOURCE_FILE@[0; 25)
-  FN_DEF@[0; 12)
-    FN_KW@[0; 2)
-    WHITESPACE@[2; 3)
-    NAME@[3; 6)
-      IDENT@[3; 6) "foo"
-    PARAM_LIST@[6; 8)
-      L_PAREN@[6; 7)
-      R_PAREN@[7; 8)
-    WHITESPACE@[8; 9)
-    BLOCK@[9; 12)
-      L_CURLY@[9; 10)
-      WHITESPACE@[10; 11)
-      R_CURLY@[11; 12)
-  WHITESPACE@[12; 13)
-  FN_DEF@[13; 25)
-    FN_KW@[13; 15)
-    WHITESPACE@[15; 16)
-    NAME@[16; 19)
-      IDENT@[16; 19) "bar"
-    PARAM_LIST@[19; 21)
-      L_PAREN@[19; 20)
-      R_PAREN@[20; 21)
-    WHITESPACE@[21; 22)
-    BLOCK@[22; 25)
-      L_CURLY@[22; 23)
-      WHITESPACE@[23; 24)
-      R_CURLY@[24; 25)
-
-"#
-        .trim()
-    );
-}
diff --git a/crates/ra_syntax/src/ast/generated.rs b/crates/ra_syntax/src/ast/generated.rs
index 54b72f8c5..47a37e4d1 100644
--- a/crates/ra_syntax/src/ast/generated.rs
+++ b/crates/ra_syntax/src/ast/generated.rs
@@ -4061,7 +4061,11 @@ impl ast::NameOwner for TraitDef {}
 impl ast::AttrsOwner for TraitDef {}
 impl ast::DocCommentsOwner for TraitDef {}
 impl ast::TypeParamsOwner for TraitDef {}
-impl TraitDef {}
+impl TraitDef {
+    pub fn item_list(&self) -> Option<&ItemList> {
+        super::child_opt(self)
+    }
+}
 
 // TrueKw
 #[derive(Debug, PartialEq, Eq, Hash)]
diff --git a/crates/ra_syntax/src/grammar.ron b/crates/ra_syntax/src/grammar.ron
index 4f8e19bd0..ad6d74162 100644
--- a/crates/ra_syntax/src/grammar.ron
+++ b/crates/ra_syntax/src/grammar.ron
@@ -292,7 +292,10 @@ Grammar(
         ], options: [["variant_list", "EnumVariantList"]] ),
         "EnumVariantList": ( collections: [["variants", "EnumVariant"]] ),
         "EnumVariant": ( traits: ["NameOwner", "DocCommentsOwner", "AttrsOwner"], options: ["Expr"] ),
-        "TraitDef": ( traits: ["VisibilityOwner", "NameOwner", "AttrsOwner", "DocCommentsOwner", "TypeParamsOwner"] ),
+        "TraitDef": (
+            traits: ["VisibilityOwner", "NameOwner", "AttrsOwner", "DocCommentsOwner", "TypeParamsOwner"],
+            options: ["ItemList"]
+        ),
         "Module": (
             traits: ["VisibilityOwner", "NameOwner", "AttrsOwner", "DocCommentsOwner" ],
             options: [ "ItemList" ]
diff --git a/docs/user/features.md b/docs/user/features.md
index b9d2aa84f..7173d88e9 100644
--- a/docs/user/features.md
+++ b/docs/user/features.md
@@ -210,7 +210,7 @@ fn main() {
 }
 ```
 
--- Fill struct fields
+- Fill struct fields
 
 ```rust
 // before:
@@ -270,7 +270,22 @@ fn foo() {
 }
 ```
 
--- Remove `dbg!`
+- Inline local variable:
+
+```rust
+// before:
+fn foo() {
+    let a<|> = 1 + 1;
+    let b = a * 10;
+}
+
+// after:
+fn foo() {
+    let b = (1 + 1) * 10;
+}
+```
+
+- Remove `dbg!`
 
 ```rust
 // before: