anchor.diff:        KClassData data = _elementMap.classes.getData(oldClass);
         IndexedLibrary oldLibrary = oldClass.library;
         LibraryEntity newLibrary = libraries.getEntity(oldLibrary.libraryIndex);
  -      IndexedClass newClass = convertClass(newLibrary, oldClass);
  +      IndexedClass newClass = new JClass(newLibrary, oldClass.name,
  +          isAbstract: oldClass.isAbstract);
         JClassEnv newEnv = env.convert(_elementMap, liveMemberUsage);
         classMap[env.cls] = classes.register(newClass, data.convert(), newEnv);
         assert(newClass.classIndex == oldClass.classIndex);
  
positive.code:                   getDartType(data.node.type))));
        assert(newTypedef.typedefIndex == oldTypedef.typedefIndex);
      }
      for (int memberIndex = 0;
          memberIndex < _elementMap.members.length;
          memberIndex++) {
  
negative.code:       IndexedLibrary oldLibrary = _elementMap.libraries.getEntity(libraryIndex);
        KLibraryEnv oldEnv = _elementMap.libraries.getEnv(oldLibrary);
        KLibraryData data = _elementMap.libraries.getData(oldLibrary);
        IndexedLibrary newLibrary =
            new JLibrary(oldLibrary.name, oldLibrary.canonicalUri);
        JLibraryEnv newEnv = oldEnv.convert(_elementMap, liveMemberUsage);
        libraryMap[oldEnv.library] =
            libraries.register<IndexedLibrary, JLibraryData, JLibraryEnv>(
  