stub out trait aliases in resolve

Author: durka

src/librustc_resolve/build_reduced_graph.rs

@@ -344,6 +344,11 @@ impl<'a> Resolver<'a> {
                 }
             }
 
+            ItemKind::TraitAlias(..) => {
+                let def = Def::TraitAlias(self.definitions.local_def_id(item.id));
+                self.define(parent, ident, TypeNS, (def, vis, sp, expansion));
+            }
+
             // These items live in both the type and value namespaces.
             ItemKind::Struct(ref struct_def, _) => {
                 // Define a name in the type namespace.
@@ -411,6 +416,7 @@ impl<'a> Resolver<'a> {
                 self.define(parent, ident, TypeNS, (module, vis, sp, expansion));
                 self.current_module = module;
             }
+
             ItemKind::MacroDef(..) | ItemKind::Mac(_) => unreachable!(),
         }
     }

src/librustc_resolve/lib.rs

@@ -474,6 +474,7 @@ impl<'a> PathSource<'a> {
             },
             PathSource::Trait => match def {
                 Def::Trait(..) => true,
+                Def::TraitAlias(..) => true,
                 _ => false,
             },
             PathSource::Expr(..) => match def {
@@ -1935,6 +1936,17 @@ impl<'a> Resolver<'a> {
                 });
             }
 
+            ItemKind::TraitAlias(ref generics, ref bounds) => {
+                // Create a new rib for the trait-wide type parameters.
+                self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
+                    let local_def_id = this.definitions.local_def_id(item.id);
+                    this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
+                        this.visit_generics(generics);
+                        walk_list!(this, visit_ty_param_bound, bounds);
+                    });
+                });
+            }
+
             ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
                 self.with_scope(item.id, |this| {
                     visit::walk_item(this, item);