16 files changed, 70 insertions, 35 deletions

diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index 117ca2fe3..78c7792bf 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -577,7 +577,7 @@ pub struct Trait {
 
 impl Trait {
     pub fn module(self, db: &impl DefDatabase) -> Module {
-        Module { id: self.id.module(db) }
+        Module { id: self.id.lookup(db).container }
     }
 
     pub fn name(self, db: &impl DefDatabase) -> Name {
diff --git a/crates/ra_hir/src/from_source.rs b/crates/ra_hir/src/from_source.rs
index b35188a21..0cf4bcae1 100644
--- a/crates/ra_hir/src/from_source.rs
+++ b/crates/ra_hir/src/from_source.rs
@@ -44,8 +44,10 @@ impl FromSource for Enum {
 impl FromSource for Trait {
     type Ast = ast::TraitDef;
     fn from_source(db: &(impl DefDatabase + AstDatabase), src: InFile<Self::Ast>) -> Option<Self> {
-        let id = from_source(db, src)?;
-        Some(Trait { id })
+        // XXX: use `.parent()` to avoid finding ourselves
+        let parent = src.value.syntax().parent()?;
+        let container = Container::find(db, src.with_value(parent).as_ref())?;
+        container.child_by_source(db)[keys::TRAIT].get(&src).copied().map(Trait::from)
     }
 }
 impl FromSource for Function {
diff --git a/crates/ra_hir/src/has_source.rs b/crates/ra_hir/src/has_source.rs
index a888fe995..c4c6d66b7 100644
--- a/crates/ra_hir/src/has_source.rs
+++ b/crates/ra_hir/src/has_source.rs
@@ -93,7 +93,7 @@ impl HasSource for Static {
 impl HasSource for Trait {
     type Ast = ast::TraitDef;
     fn source(self, db: &impl DefDatabase) -> InFile<ast::TraitDef> {
-        self.id.source(db)
+        self.id.lookup(db).source(db)
     }
 }
 impl HasSource for TypeAlias {
diff --git a/crates/ra_hir_def/src/attr.rs b/crates/ra_hir_def/src/attr.rs
index 12d4e777a..3347d819c 100644
--- a/crates/ra_hir_def/src/attr.rs
+++ b/crates/ra_hir_def/src/attr.rs
@@ -60,7 +60,7 @@ impl Attrs {
                 AdtId::EnumId(it) => attrs_from_ast(it.lookup_intern(db).ast_id, db),
                 AdtId::UnionId(it) => attrs_from_ast(it.lookup_intern(db).ast_id, db),
             },
-            AttrDefId::TraitId(it) => attrs_from_ast(it.lookup_intern(db).ast_id, db),
+            AttrDefId::TraitId(it) => attrs_from_loc(it.lookup(db), db),
             AttrDefId::MacroDefId(it) => {
                 it.ast_id.map_or_else(Default::default, |ast_id| attrs_from_ast(ast_id, db))
             }
diff --git a/crates/ra_hir_def/src/child_by_source.rs b/crates/ra_hir_def/src/child_by_source.rs
index 821549bd5..88c2d3f24 100644
--- a/crates/ra_hir_def/src/child_by_source.rs
+++ b/crates/ra_hir_def/src/child_by_source.rs
@@ -94,6 +94,10 @@ impl ChildBySource for ModuleId {
                     let src = ty.lookup(db).source(db);
                     res[keys::TYPE_ALIAS].insert(src, ty)
                 }
+                ModuleDefId::TraitId(trait_) => {
+                    let src = trait_.lookup(db).source(db);
+                    res[keys::TRAIT].insert(src, trait_)
+                }
                 _ => (),
             }
         }
diff --git a/crates/ra_hir_def/src/data.rs b/crates/ra_hir_def/src/data.rs
index 42821b9b1..b2dac183e 100644
--- a/crates/ra_hir_def/src/data.rs
+++ b/crates/ra_hir_def/src/data.rs
@@ -12,8 +12,8 @@ use crate::{
     db::DefDatabase,
     src::HasSource,
     type_ref::{Mutability, TypeRef},
-    AssocItemId, AstItemDef, ConstId, ConstLoc, ContainerId, FunctionId, FunctionLoc, ImplId,
-    Intern, Lookup, StaticId, TraitId, TypeAliasId, TypeAliasLoc,
+    AssocItemId, ConstId, ConstLoc, ContainerId, FunctionId, FunctionLoc, ImplId, Intern, Lookup,
+    StaticId, TraitId, TypeAliasId, TypeAliasLoc,
 };
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -94,7 +94,7 @@ pub struct TraitData {
 
 impl TraitData {
     pub(crate) fn trait_data_query(db: &impl DefDatabase, tr: TraitId) -> Arc<TraitData> {
-        let src = tr.source(db);
+        let src = tr.lookup(db).source(db);
         let name = src.value.name().map_or_else(Name::missing, |n| n.as_name());
         let auto = src.value.is_auto();
         let ast_id_map = db.ast_id_map(src.file_id);
diff --git a/crates/ra_hir_def/src/db.rs b/crates/ra_hir_def/src/db.rs
index 8907aacca..f0c2ae559 100644
--- a/crates/ra_hir_def/src/db.rs
+++ b/crates/ra_hir_def/src/db.rs
@@ -18,8 +18,8 @@ use crate::{
         CrateDefMap,
     },
     AttrDefId, ConstId, ConstLoc, DefWithBodyId, EnumId, FunctionId, FunctionLoc, GenericDefId,
-    ImplId, ImplLoc, ItemLoc, ModuleId, StaticId, StaticLoc, StructId, TraitId, TypeAliasId,
-    TypeAliasLoc, UnionId,
+    ImplId, ImplLoc, ItemLoc, ModuleId, StaticId, StaticLoc, StructId, TraitId, TraitLoc,
+    TypeAliasId, TypeAliasLoc, UnionId,
 };
 
 #[salsa::query_group(InternDatabaseStorage)]
@@ -37,7 +37,7 @@ pub trait InternDatabase: SourceDatabase {
     #[salsa::interned]
     fn intern_static(&self, loc: StaticLoc) -> StaticId;
     #[salsa::interned]
-    fn intern_trait(&self, loc: ItemLoc<ast::TraitDef>) -> TraitId;
+    fn intern_trait(&self, loc: TraitLoc) -> TraitId;
     #[salsa::interned]
     fn intern_type_alias(&self, loc: TypeAliasLoc) -> TypeAliasId;
     #[salsa::interned]
diff --git a/crates/ra_hir_def/src/docs.rs b/crates/ra_hir_def/src/docs.rs
index 61727bd26..1921681fb 100644
--- a/crates/ra_hir_def/src/docs.rs
+++ b/crates/ra_hir_def/src/docs.rs
@@ -59,7 +59,7 @@ impl Documentation {
                 let src = it.parent.child_source(db);
                 docs_from_ast(&src.value[it.local_id])
             }
-            AttrDefId::TraitId(it) => docs_from_ast(&it.source(db).value),
+            AttrDefId::TraitId(it) => docs_from_ast(&it.lookup(db).source(db).value),
             AttrDefId::MacroDefId(it) => docs_from_ast(&it.ast_id?.to_node(db)),
             AttrDefId::ConstId(it) => docs_from_ast(&it.lookup(db).source(db).value),
             AttrDefId::StaticId(it) => docs_from_ast(&it.lookup(db).source(db).value),
diff --git a/crates/ra_hir_def/src/generics.rs b/crates/ra_hir_def/src/generics.rs
index 5d1100945..cbfc3ff04 100644
--- a/crates/ra_hir_def/src/generics.rs
+++ b/crates/ra_hir_def/src/generics.rs
@@ -86,7 +86,7 @@ impl GenericParams {
                 src.file_id
             }
             GenericDefId::TraitId(it) => {
-                let src = it.source(db);
+                let src = it.lookup(db).source(db);
 
                 // traits get the Self type as an implicit first type parameter
                 let self_param_id =
diff --git a/crates/ra_hir_def/src/keys.rs b/crates/ra_hir_def/src/keys.rs
index d318b2451..6ec58f5f9 100644
--- a/crates/ra_hir_def/src/keys.rs
+++ b/crates/ra_hir_def/src/keys.rs
@@ -8,7 +8,8 @@ use rustc_hash::FxHashMap;
 
 use crate::{
     dyn_map::{DynMap, Policy},
-    ConstId, EnumVariantId, FunctionId, ImplId, StaticId, StructFieldId, TypeAliasId, TypeParamId,
+    ConstId, EnumVariantId, FunctionId, ImplId, StaticId, StructFieldId, TraitId, TypeAliasId,
+    TypeParamId,
 };
 
 type Key<K, V> = crate::dyn_map::Key<InFile<K>, V, AstPtrPolicy<K, V>>;
@@ -18,6 +19,7 @@ pub const CONST: Key<ast::ConstDef, ConstId> = Key::new();
 pub const STATIC: Key<ast::StaticDef, StaticId> = Key::new();
 pub const TYPE_ALIAS: Key<ast::TypeAliasDef, TypeAliasId> = Key::new();
 pub const IMPL: Key<ast::ImplBlock, ImplId> = Key::new();
+pub const TRAIT: Key<ast::TraitDef, TraitId> = Key::new();
 
 pub const ENUM_VARIANT: Key<ast::EnumVariant, EnumVariantId> = Key::new();
 pub const TUPLE_FIELD: Key<ast::TupleFieldDef, StructFieldId> = Key::new();
diff --git a/crates/ra_hir_def/src/lib.rs b/crates/ra_hir_def/src/lib.rs
index 5564b166b..0fcc2cde4 100644
--- a/crates/ra_hir_def/src/lib.rs
+++ b/crates/ra_hir_def/src/lib.rs
@@ -253,12 +253,24 @@ impl Lookup for StaticId {
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct TraitId(salsa::InternId);
 impl_intern_key!(TraitId);
-impl AstItemDef<ast::TraitDef> for TraitId {
-    fn intern(db: &impl InternDatabase, loc: ItemLoc<ast::TraitDef>) -> Self {
-        db.intern_trait(loc)
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct TraitLoc {
+    pub container: ModuleId,
+    pub ast_id: AstId<ast::TraitDef>,
+}
+
+impl Intern for TraitLoc {
+    type ID = TraitId;
+    fn intern(self, db: &impl db::DefDatabase) -> TraitId {
+        db.intern_trait(self)
     }
-    fn lookup_intern(self, db: &impl InternDatabase) -> ItemLoc<ast::TraitDef> {
-        db.lookup_intern_trait(self)
+}
+
+impl Lookup for TraitId {
+    type Data = TraitLoc;
+    fn lookup(&self, db: &impl db::DefDatabase) -> TraitLoc {
+        db.lookup_intern_trait(*self)
     }
 }
 
@@ -492,7 +504,7 @@ impl HasModule for FunctionLoc {
         match self.container {
             ContainerId::ModuleId(it) => it,
             ContainerId::ImplId(it) => it.lookup(db).container,
-            ContainerId::TraitId(it) => it.module(db),
+            ContainerId::TraitId(it) => it.lookup(db).container,
         }
     }
 }
@@ -502,7 +514,7 @@ impl HasModule for TypeAliasLoc {
         match self.container {
             ContainerId::ModuleId(it) => it,
             ContainerId::ImplId(it) => it.lookup(db).container,
-            ContainerId::TraitId(it) => it.module(db),
+            ContainerId::TraitId(it) => it.lookup(db).container,
         }
     }
 }
@@ -512,7 +524,7 @@ impl HasModule for ConstLoc {
         match self.container {
             ContainerId::ModuleId(it) => it,
             ContainerId::ImplId(it) => it.lookup(db).container,
-            ContainerId::TraitId(it) => it.module(db),
+            ContainerId::TraitId(it) => it.lookup(db).container,
         }
     }
 }
@@ -542,7 +554,7 @@ impl HasModule for GenericDefId {
         match self {
             GenericDefId::FunctionId(it) => it.lookup(db).module(db),
             GenericDefId::AdtId(it) => it.module(db),
-            GenericDefId::TraitId(it) => it.module(db),
+            GenericDefId::TraitId(it) => it.lookup(db).container,
             GenericDefId::TypeAliasId(it) => it.lookup(db).module(db),
             GenericDefId::ImplId(it) => it.lookup(db).container,
             GenericDefId::EnumVariantId(it) => it.parent.module(db),
diff --git a/crates/ra_hir_def/src/nameres/collector.rs b/crates/ra_hir_def/src/nameres/collector.rs
index b33507a9a..a7bdd620b 100644
--- a/crates/ra_hir_def/src/nameres/collector.rs
+++ b/crates/ra_hir_def/src/nameres/collector.rs
@@ -26,7 +26,7 @@ use crate::{
     per_ns::PerNs,
     AdtId, AstId, AstItemDef, ConstLoc, ContainerId, EnumId, EnumVariantId, FunctionLoc, ImplLoc,
     Intern, LocalImportId, LocalModuleId, LocationCtx, ModuleDefId, ModuleId, StaticLoc, StructId,
-    TraitId, TypeAliasLoc, UnionId,
+    TraitLoc, TypeAliasLoc, UnionId,
 };
 
 pub(super) fn collect_defs(db: &impl DefDatabase, mut def_map: CrateDefMap) -> CrateDefMap {
@@ -796,7 +796,12 @@ where
 
                 PerNs::values(def.into())
             }
-            raw::DefKind::Trait(ast_id) => PerNs::types(TraitId::from_ast_id(ctx, ast_id).into()),
+            raw::DefKind::Trait(ast_id) => {
+                let def = TraitLoc { container: module, ast_id: AstId::new(self.file_id, ast_id) }
+                    .intern(self.def_collector.db);
+
+                PerNs::types(def.into())
+            }
             raw::DefKind::TypeAlias(ast_id) => {
                 let def = TypeAliasLoc {
                     container: ContainerId::ModuleId(module),
diff --git a/crates/ra_hir_def/src/resolver.rs b/crates/ra_hir_def/src/resolver.rs
index f87b16b44..17b2169d2 100644
--- a/crates/ra_hir_def/src/resolver.rs
+++ b/crates/ra_hir_def/src/resolver.rs
@@ -17,9 +17,9 @@ use crate::{
     nameres::{BuiltinShadowMode, CrateDefMap},
     path::{Path, PathKind},
     per_ns::PerNs,
-    AdtId, AstItemDef, ConstId, ContainerId, DefWithBodyId, EnumId, EnumVariantId, FunctionId,
-    GenericDefId, HasModule, ImplId, LocalModuleId, Lookup, ModuleDefId, ModuleId, StaticId,
-    StructId, TraitId, TypeAliasId, TypeParamId, VariantId,
+    AdtId, ConstId, ContainerId, DefWithBodyId, EnumId, EnumVariantId, FunctionId, GenericDefId,
+    HasModule, ImplId, LocalModuleId, Lookup, ModuleDefId, ModuleId, StaticId, StructId, TraitId,
+    TypeAliasId, TypeParamId, VariantId,
 };
 
 #[derive(Debug, Clone, Default)]
@@ -524,7 +524,7 @@ impl HasResolver for ModuleId {
 
 impl HasResolver for TraitId {
     fn resolver(self, db: &impl DefDatabase) -> Resolver {
-        self.module(db).resolver(db).push_generic_params_scope(db, self.into())
+        self.lookup(db).container.resolver(db).push_generic_params_scope(db, self.into())
     }
 }
 
diff --git a/crates/ra_hir_def/src/src.rs b/crates/ra_hir_def/src/src.rs
index a5c4359a7..858e4861e 100644
--- a/crates/ra_hir_def/src/src.rs
+++ b/crates/ra_hir_def/src/src.rs
@@ -4,7 +4,7 @@ use hir_expand::InFile;
 use ra_arena::map::ArenaMap;
 use ra_syntax::ast;
 
-use crate::{db::DefDatabase, ConstLoc, FunctionLoc, ImplLoc, StaticLoc, TypeAliasLoc};
+use crate::{db::DefDatabase, ConstLoc, FunctionLoc, ImplLoc, StaticLoc, TraitLoc, TypeAliasLoc};
 
 pub trait HasSource {
     type Value;
@@ -56,6 +56,15 @@ impl HasSource for ImplLoc {
     }
 }
 
+impl HasSource for TraitLoc {
+    type Value = ast::TraitDef;
+
+    fn source(&self, db: &impl DefDatabase) -> InFile<ast::TraitDef> {
+        let node = self.ast_id.to_node(db);
+        InFile::new(self.ast_id.file_id, node)
+    }
+}
+
 pub trait HasChildSource {
     type ChildId;
     type Value;
diff --git a/crates/ra_hir_expand/src/builtin_macro.rs b/crates/ra_hir_expand/src/builtin_macro.rs
index ec5ace757..be5f3cbe3 100644
--- a/crates/ra_hir_expand/src/builtin_macro.rs
+++ b/crates/ra_hir_expand/src/builtin_macro.rs
@@ -367,6 +367,9 @@ mod tests {
             BuiltinFnLikeExpander::FormatArgs,
         );
 
-        assert_eq!(expanded, r#"std::fmt::Arguments::new_v1(&[] ,&[std::fmt::ArgumentV1::new(&(arg1(a,b,c)),std::fmt::Display::fmt),std::fmt::ArgumentV1::new(&(arg2),std::fmt::Display::fmt),])"#);
+        assert_eq!(
+            expanded,
+            r#"std::fmt::Arguments::new_v1(&[] ,&[std::fmt::ArgumentV1::new(&(arg1(a,b,c)),std::fmt::Display::fmt),std::fmt::ArgumentV1::new(&(arg2),std::fmt::Display::fmt),])"#
+        );
     }
 }
diff --git a/crates/ra_hir_ty/src/traits/chalk.rs b/crates/ra_hir_ty/src/traits/chalk.rs
index ff299f511..fc21872b2 100644
--- a/crates/ra_hir_ty/src/traits/chalk.rs
+++ b/crates/ra_hir_ty/src/traits/chalk.rs
@@ -9,9 +9,7 @@ use chalk_ir::{
 };
 use chalk_rust_ir::{AssociatedTyDatum, AssociatedTyValue, ImplDatum, StructDatum, TraitDatum};
 
-use hir_def::{
-    AssocItemId, AstItemDef, ContainerId, GenericDefId, ImplId, Lookup, TraitId, TypeAliasId,
-};
+use hir_def::{AssocItemId, ContainerId, GenericDefId, ImplId, Lookup, TraitId, TypeAliasId};
 use ra_db::{
     salsa::{InternId, InternKey},
     CrateId,
@@ -593,7 +591,7 @@ pub(crate) fn trait_datum_query(
     let bound_vars = Substs::bound_vars(&generic_params);
     let flags = chalk_rust_ir::TraitFlags {
         auto: trait_data.auto,
-        upstream: trait_.module(db).krate != krate,
+        upstream: trait_.lookup(db).container.krate != krate,
         non_enumerable: true,
         coinductive: false, // only relevant for Chalk testing
         // FIXME set these flags correctly