Fix calling object methods and properties on function types

pkg/analyzer/lib/src/generated/testing/test_type_provider.dart

Index: pkg/analyzer/lib/src/generated/testing/test_type_provider.dart
diff --git a/pkg/analyzer/lib/src/generated/testing/test_type_provider.dart b/pkg/analyzer/lib/src/generated/testing/test_type_provider.dart
index 0a524fac9ec53f48d0bbc192a3589a7408bc3b96..6303495f752fd743ae64885b170c304f339ba128 100644
--- a/pkg/analyzer/lib/src/generated/testing/test_type_provider.dart
+++ b/pkg/analyzer/lib/src/generated/testing/test_type_provider.dart
@@ -22,7 +22,9 @@ import 'package:analyzer/src/generated/testing/element_factory.dart';
  * A type provider that can be used by tests without creating the element model
  * for the core library.
  */
-class TestTypeProvider implements TypeProvider {
+class TestTypeProvider extends Object
+    with TypeProviderBaseMixin
+    implements TypeProvider {
   /**
    * The type representing the built-in type 'bool'.
    */
@@ -388,16 +390,6 @@ class TestTypeProvider implements TypeProvider {
   }
 
   @override
-  List<InterfaceType> get nonSubtypableTypes => <InterfaceType>[
-        nullType,
-        numType,
-        intType,
-        doubleType,
-        boolType,
-        stringType
-      ];
-
-  @override
   DartObjectImpl get nullObject {
     if (_nullObject == null) {
       _nullObject = new DartObjectImpl(nullType, NullState.NULL_STATE);