anchor.diff:      if (factory == null) {
         return super.createCacheFromSourceFactory(factory);
       }
  -    return new AnalysisCache(
  +    return AnalysisCache(
           <CachePartition>[AnalysisEngine.instance.partitionManager.forSdk(sdk)]);
     }
   }
  
positive.code:       [this.parts = const <String, String>{}]);
  
    @override
    String get category => throw new UnimplementedError();
  
    @override
    bool get isDart2JsLibrary => throw new UnimplementedError();
  
    @override
    bool get isDocumented => throw new UnimplementedError();
  
    @override
    bool get isImplementation => throw new UnimplementedError();
  
    @override
    bool get isInternal => shortName.startsWith('dart:_');
  
    @override
    bool get isShared => throw new UnimplementedError();
  
    @override
    bool get isVmLibrary => throw new UnimplementedError();
  }
  
  /// An [AnalysisContextImpl] that only contains sources for a Dart SDK.
  
negative.code:       } else {
          bytes = _computeLinkedBundleBytes();
        }
        _bundle = PackageBundle.fromBuffer(bytes);
      }
      return _bundle;
    }
  