anchor.diff:     * The [AnalysisContext] which is used for all of the sources.
      */
     InternalAnalysisContext _analysisContext;
  +
  +  /**
  +   * The cached linked bundle of the SDK.
  +   */
  +  PackageBundle _bundle;
   
     MockSdk({resource.ResourceProvider resourceProvider})
         : provider = resourceProvider ?? new resource.MemoryResourceProvider() {
  
positive.code:   }
  
    @override
    PackageBundle getLinkedBundle() => null;
  
    @override
    SdkLibrary getSdkLibrary(String dartUri) {
  
negative.code: import 'package:analyzer/src/generated/sdk.dart';
  import 'package:analyzer/src/generated/source.dart';
  import 'package:analyzer/src/summary/idl.dart' show PackageBundle;
  import 'package:analyzer/src/summary/summary_file_builder.dart';
  
  class MockSdk implements DartSdk {
    static const MockSdkLibrary LIB_CORE = const MockSdkLibrary(
  