5 files changed, 79 insertions, 21 deletions

diff --git a/crates/ra_hir_def/src/attr.rs b/crates/ra_hir_def/src/attr.rs
index 2eeba0572..deea83a6d 100644
--- a/crates/ra_hir_def/src/attr.rs
+++ b/crates/ra_hir_def/src/attr.rs
@@ -13,7 +13,11 @@ use ra_syntax::{
 use tt::Subtree;
 
 use crate::{
-    db::DefDatabase, nameres::ModuleSource, path::ModPath, src::HasChildSource, src::HasSource,
+    db::DefDatabase,
+    item_tree::{ItemTreeId, ItemTreeNode},
+    nameres::ModuleSource,
+    path::ModPath,
+    src::HasChildSource,
     AdtId, AttrDefId, Lookup,
 };
 
@@ -65,19 +69,19 @@ impl Attrs {
                 Attrs::from_attrs_owner(db, src.map(|it| it as &dyn AttrsOwner))
             }
             AttrDefId::AdtId(it) => match it {
-                AdtId::StructId(it) => attrs_from_loc(it.lookup(db), db),
-                AdtId::EnumId(it) => attrs_from_loc(it.lookup(db), db),
-                AdtId::UnionId(it) => attrs_from_loc(it.lookup(db), db),
+                AdtId::StructId(it) => attrs_from_item_tree(it.lookup(db).id, db),
+                AdtId::EnumId(it) => attrs_from_item_tree(it.lookup(db).id, db),
+                AdtId::UnionId(it) => attrs_from_item_tree(it.lookup(db).id, db),
             },
-            AttrDefId::TraitId(it) => attrs_from_loc(it.lookup(db), db),
+            AttrDefId::TraitId(it) => attrs_from_item_tree(it.lookup(db).id, db),
             AttrDefId::MacroDefId(it) => {
                 it.ast_id.map_or_else(Default::default, |ast_id| attrs_from_ast(ast_id, db))
             }
-            AttrDefId::ImplId(it) => attrs_from_loc(it.lookup(db), db),
-            AttrDefId::ConstId(it) => attrs_from_loc(it.lookup(db), db),
-            AttrDefId::StaticId(it) => attrs_from_loc(it.lookup(db), db),
-            AttrDefId::FunctionId(it) => attrs_from_loc(it.lookup(db), db),
-            AttrDefId::TypeAliasId(it) => attrs_from_loc(it.lookup(db), db),
+            AttrDefId::ImplId(it) => attrs_from_item_tree(it.lookup(db).id, db),
+            AttrDefId::ConstId(it) => attrs_from_item_tree(it.lookup(db).id, db),
+            AttrDefId::StaticId(it) => attrs_from_item_tree(it.lookup(db).id, db),
+            AttrDefId::FunctionId(it) => attrs_from_item_tree(it.lookup(db).id, db),
+            AttrDefId::TypeAliasId(it) => attrs_from_item_tree(it.lookup(db).id, db),
         }
     }
 
@@ -187,11 +191,8 @@ where
     Attrs::from_attrs_owner(db, src.as_ref().map(|it| it as &dyn AttrsOwner))
 }
 
-fn attrs_from_loc<T>(node: T, db: &dyn DefDatabase) -> Attrs
-where
-    T: HasSource,
-    T::Value: ast::AttrsOwner,
-{
-    let src = node.source(db);
-    Attrs::from_attrs_owner(db, src.as_ref().map(|it| it as &dyn AttrsOwner))
+fn attrs_from_item_tree<N: ItemTreeNode>(id: ItemTreeId<N>, db: &dyn DefDatabase) -> Attrs {
+    let tree = db.item_tree(id.file_id);
+    let mod_item = N::id_to_mod_item(id.value);
+    tree.attrs(mod_item).clone()
 }
diff --git a/crates/ra_hir_def/src/generics.rs b/crates/ra_hir_def/src/generics.rs
index ed4f60c66..c4b9f626f 100644
--- a/crates/ra_hir_def/src/generics.rs
+++ b/crates/ra_hir_def/src/generics.rs
@@ -74,8 +74,53 @@ impl GenericParams {
         def: GenericDefId,
     ) -> Arc<GenericParams> {
         let _p = profile("generic_params_query");
-        let (params, _source_map) = GenericParams::new(db, def);
-        Arc::new(params)
+
+        let generics = match def {
+            GenericDefId::FunctionId(id) => {
+                let id = id.lookup(db).id;
+                let tree = db.item_tree(id.file_id);
+                let item = &tree[id.value];
+                item.generic_params.clone()
+            }
+            GenericDefId::AdtId(AdtId::StructId(id)) => {
+                let id = id.lookup(db).id;
+                let tree = db.item_tree(id.file_id);
+                let item = &tree[id.value];
+                item.generic_params.clone()
+            }
+            GenericDefId::AdtId(AdtId::EnumId(id)) => {
+                let id = id.lookup(db).id;
+                let tree = db.item_tree(id.file_id);
+                let item = &tree[id.value];
+                item.generic_params.clone()
+            }
+            GenericDefId::AdtId(AdtId::UnionId(id)) => {
+                let id = id.lookup(db).id;
+                let tree = db.item_tree(id.file_id);
+                let item = &tree[id.value];
+                item.generic_params.clone()
+            }
+            GenericDefId::TraitId(id) => {
+                let id = id.lookup(db).id;
+                let tree = db.item_tree(id.file_id);
+                let item = &tree[id.value];
+                item.generic_params.clone()
+            }
+            GenericDefId::TypeAliasId(id) => {
+                let id = id.lookup(db).id;
+                let tree = db.item_tree(id.file_id);
+                let item = &tree[id.value];
+                item.generic_params.clone()
+            }
+            GenericDefId::ImplId(id) => {
+                let id = id.lookup(db).id;
+                let tree = db.item_tree(id.file_id);
+                let item = &tree[id.value];
+                item.generic_params.clone()
+            }
+            GenericDefId::EnumVariantId(_) | GenericDefId::ConstId(_) => GenericParams::default(),
+        };
+        Arc::new(generics)
     }
 
     fn new(db: &dyn DefDatabase, def: GenericDefId) -> (GenericParams, InFile<SourceMap>) {
diff --git a/crates/ra_hir_def/src/item_tree.rs b/crates/ra_hir_def/src/item_tree.rs
index 59a4a411a..efcb5dc60 100644
--- a/crates/ra_hir_def/src/item_tree.rs
+++ b/crates/ra_hir_def/src/item_tree.rs
@@ -175,6 +175,9 @@ pub trait ItemTreeNode: Clone {
 
     /// Downcasts a `ModItem` to a `FileItemTreeId` specific to this type.
     fn id_from_mod_item(mod_item: ModItem) -> Option<FileItemTreeId<Self>>;
+
+    /// Upcasts a `FileItemTreeId` to a generic `ModItem`.
+    fn id_to_mod_item(id: FileItemTreeId<Self>) -> ModItem;
 }
 
 /// Trait for item tree nodes that allow accessing the original AST node.
@@ -232,6 +235,10 @@ macro_rules! nodes {
                     None
                 }
             }
+
+            fn id_to_mod_item(id: FileItemTreeId<Self>) -> ModItem {
+                ModItem::$node(id)
+            }
         }
     )+ };
 }
diff --git a/crates/ra_hir_def/src/item_tree/lower.rs b/crates/ra_hir_def/src/item_tree/lower.rs
index 42af8bb5e..841c7a852 100644
--- a/crates/ra_hir_def/src/item_tree/lower.rs
+++ b/crates/ra_hir_def/src/item_tree/lower.rs
@@ -553,7 +553,12 @@ impl Ctx {
 
                 generics.fill(&self.body_ctx, &mut sm, node);
             }
-            GenericsOwner::Impl => {}
+            GenericsOwner::Impl => {
+                // Note that we don't add `Self` here: in `impl`s, `Self` is not a
+                // type-parameter, but rather is a type-alias for impl's target
+                // type, so this is handled by the resolver.
+                generics.fill(&self.body_ctx, &mut sm, node);
+            }
         }
         generics
     }
diff --git a/crates/ra_hir_def/src/item_tree/tests.rs b/crates/ra_hir_def/src/item_tree/tests.rs
index 1db1ce7a9..7b8523b9f 100644
--- a/crates/ra_hir_def/src/item_tree/tests.rs
+++ b/crates/ra_hir_def/src/item_tree/tests.rs
@@ -200,7 +200,7 @@ fn simple_inner_items() {
 inner attrs: Attrs { entries: None }
 
 top-level items:
-Impl { generic_params: GenericParams { types: Arena { len: 0, data: [] }, where_predicates: [] }, target_trait: Some(Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("D"))] }, generic_args: [None] })), target_type: Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("Response"))] }, generic_args: [Some(GenericArgs { args: [Type(Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("T"))] }, generic_args: [None] }))], has_self_type: false, bindings: [] })] }), is_negative: false, items: [Function(Idx::<Function>(1))], ast_id: FileAstId::<ra_syntax::ast::generated::nodes::ImplDef>(0) }
+Impl { generic_params: GenericParams { types: Arena { len: 1, data: [TypeParamData { name: Some(Name(Text("T"))), default: None, provenance: TypeParamList }] }, where_predicates: [WherePredicate { target: TypeRef(Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("T"))] }, generic_args: [None] })), bound: Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("A"))] }, generic_args: [None] }) }] }, target_trait: Some(Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("D"))] }, generic_args: [None] })), target_type: Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("Response"))] }, generic_args: [Some(GenericArgs { args: [Type(Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("T"))] }, generic_args: [None] }))], has_self_type: false, bindings: [] })] }), is_negative: false, items: [Function(Idx::<Function>(1))], ast_id: FileAstId::<ra_syntax::ast::generated::nodes::ImplDef>(0) }
 
 inner items:
 FileAstId::<ra_syntax::ast::generated::nodes::ModuleItem>(2):