anchor.diff:      // nodes
       FieldDeclaration nodeA = helper.newMembers[0];
       FieldDeclaration newNodeB = helper.newMembers[1];
  +    List<VariableDeclaration> fieldsA = nodeA.fields.variables;
       List<VariableDeclaration> newFieldsB = newNodeB.fields.variables;
       expect(nodeA, same(helper.oldMembers[0]));
       expect(newFieldsB, hasLength(1));
       // elements
  +    FieldElement fieldElementA = fieldsA[0].name.staticElement;
       FieldElement newFieldElementB = newFieldsB[0].name.staticElement;
       expect(newFieldElementB.name, 'bbb');
  +    // members
  +    ClassElement classElement = helper.element;
  +    expect(classElement.fields, [fieldElementA, newFieldElementB]);
       // verify delta
       expect(helper.delta.hasAnnotationChanges, isFalse);
       expect(helper.delta.addedConstructors, isEmpty);
  
positive.code:     expect(elementB.name, 'b');
      // classElement.constructors
      ClassElement classElement = helper.element;
      expect(classElement.constructors, unorderedEquals([elementB]));
      // verify delta
      expect(helper.delta.addedConstructors, unorderedEquals([]));
      expect(helper.delta.removedConstructors, unorderedEquals([oldElementA]));
  
negative.code:     expect(newElementA.name, 'aaa2');
      expect(elementB, isNotNull);
      expect(elementB.name, 'bbb');
      expect(helper.element.methods, [newElementA, elementB]);
      // verify delta
      expect(helper.delta.addedConstructors, isEmpty);
      expect(helper.delta.removedConstructors, isEmpty);
  