Abstract over the type system.

pkg/analyzer/test/generated/engine_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library engine.engine_test;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/file_system/memory_file_system.dart';
@@ skipping 5800 matching lines @@
     fail("Unexpected invocation of getTypeProvider");
     return null;
   }
 
   @override
   void set typeProvider(TypeProvider typeProvider) {
     fail("Unexpected invocation of set typeProvider");
   }
 
   @override
+  TypeSystem get typeSystem {
+    fail("Unexpected invocation of getTypeSystem");
+    return null;
+  }
+
+  @override
   TypeResolverVisitorFactory get typeResolverVisitorFactory {
     fail("Unexpected invocation of getTypeResolverVisitorFactory");
     return null;
   }
 
   @override
   void addListener(AnalysisListener listener) {
     fail("Unexpected invocation of addListener");
   }
 
@@ skipping 1175 matching lines @@
   @override
   bool exists() => true;
 }
 
 class _UniversalCachePartitionTest_test_setMaxCacheSize
     implements CacheRetentionPolicy {
   @override
   RetentionPriority getAstPriority(Source source, SourceEntry sourceEntry) =>
       RetentionPriority.LOW;
 }