add completions to show only traits with qualified path prefix

Author: dfireBird

crates/ide-completion/src/completions/type.rs

@@ -31,6 +31,11 @@ pub(crate) fn complete_type_path(
             ScopeDef::ImplSelfType(_) => location.complete_self_type(),
             // Don't suggest attribute macros and derives.
             ScopeDef::ModuleDef(Macro(mac)) => mac.is_fn_like(ctx.db),
+            ScopeDef::ModuleDef(Trait(_) | Module(_))
+                if matches!(location, TypeLocation::ImplTrait) =>
+            {
+                true
+            }
             // Type things are fine
             ScopeDef::ModuleDef(
                 BuiltinType(_) | Adt(_) | Module(_) | Trait(_) | TraitAlias(_) | TypeAlias(_),
@@ -187,8 +192,13 @@ pub(crate) fn complete_type_path(
                 TypeLocation::ImplTrait => {
                     acc.add_nameref_keywords_with_colon(ctx);
                     ctx.process_all_names(&mut |name, def, doc_aliases| {
-                        let is_trait = matches!(def, ScopeDef::ModuleDef(hir::ModuleDef::Trait(_)));
-                        if is_trait {
+                        let is_trait_or_module = matches!(
+                            def,
+                            ScopeDef::ModuleDef(
+                                hir::ModuleDef::Module(_) | hir::ModuleDef::Trait(_)
+                            )
+                        );
+                        if is_trait_or_module {
                             acc.add_path_resolution(ctx, path_ctx, name, def, doc_aliases);
                         }
                     });

crates/ide-completion/src/context.rs

@@ -202,6 +202,7 @@ impl TypeLocation {
             }
             TypeLocation::AssocConstEq => false,
             TypeLocation::AssocTypeEq => true,
+            TypeLocation::ImplTrait => false,
             _ => true,
         }
     }

crates/ide-completion/src/tests/type_pos.rs

@@ -998,12 +998,34 @@ trait Foo {}
 
 struct Bar;
 
-impl $0 for Bar { }"#,
+impl $0 for Bar { }
+"#,
         expect![[r#"
+            md module
             tt Foo
             tt Trait
             kw crate::
             kw self::
         "#]],
     );
 }
+
+#[test]
+fn complete_traits_with_path_on_impl_trait_block() {
+    check(
+        r#"
+mod outer {
+    pub trait Foo {}
+    pub struct Bar;
+    pub mod inner {
+    }
+}
+
+impl outer::$0 for Bar { }
+"#,
+        expect![[r#"
+            md inner
+            tt Foo
+        "#]],
+    );
+}