anchor.diff:      });
     }
   
  +  void _reset() {
  +    serializedSources.clear();
  +    bundleAssembler = new PackageBundleAssembler();
  +    uriToUnit.clear();
  +  }
  +
     void _serializeLibrary(Source librarySource) {
       if (librarySource.isInSystemLibrary) {
         return;
  
positive.code:   @failingTest
    void test_constructors_inferFromArguments_redirectingFactory() {
      super.test_constructors_inferFromArguments_redirectingFactory();
    }
  
    @override
    @failingTest
    void test_futureThen() {
      super.test_futureThen();
    }
  
    @override
    @failingTest
    void test_futureThen_conditional() {
      super.test_futureThen_conditional();
    }
  
    @override
    @failingTest
    void test_futureThen_upwards() {
      super.test_futureThen_upwards();
    }
  
    @override
    @failingTest
    void test_futureUnion_asyncConditional() {
      super.test_futureUnion_asyncConditional();
    }
  
    @override
    @failingTest
    void test_futureUnion_downwards() {
      super.test_futureUnion_downwards();
    }
  
    @override
  
negative.code: abstract class _AstResynthesizeTestMixin
      implements _AstResynthesizeTestMixinInterface {
    final Set<Source> serializedSources = new Set<Source>();
    PackageBundleAssembler bundleAssembler = new PackageBundleAssembler();
    final Map<String, UnlinkedUnitBuilder> uriToUnit =
        <String, UnlinkedUnitBuilder>{};
  
  