anchor.diff:  }
   
   @reflectiveTest
  -class ClosedWorldClassHierarchyTest extends _ClassHierarchyTest {
  +class ClosedWorldClassHierarchyTest {
  +  Component component;
  +  CoreTypes coreTypes;
  +
  +  /// The test library.
  +  Library library;
  +
  +  ClassHierarchy _hierarchy;
  +
     ClassHierarchy createClassHierarchy(Component component) {
       return new ClassHierarchy(component);
     }
  
positive.code:         implementedTypes: implements_.map((c) => c.asThisSupertype).toList()));
    }
  
    ClassHierarchy createClassHierarchy(Component component);
  
    Procedure newEmptyGetter(String name,
        {DartType returnType: const DynamicType(), bool isAbstract: false}) {
      var body =
  
negative.code:     expect(cwchst.getSubtypesOf(g), unorderedEquals([g, h]));
      expect(cwchst.getSubtypesOf(h), unorderedEquals([h]));
    }
  
    /// Return the new or existing instance of [ClassHierarchy].
    ClassHierarchy get hierarchy {
  