anchor.diff:          name = json['name'],
           rawKind = json['kind'],
           id = json['id'],
  -        comment = json['comment'],
  -        isPrivate = json['isPrivate'] == true,
  -        mdnCommentHtml = json['mdnCommentHtml'],
  -        mdnUrl = json['mdnUrl'],
  -        _uri = json['uri'],
  -        _line = json['line'],
           loading = false {
  -        _children = _jsonDeserializeArray(json['children'], this);
  +    _loadFromJson(json);
     }
   
     Element._clone(Element e, Element newParent)
  
positive.code:         mdnUrl = null,
          _children = <Element>[];
    
    /**
     * Create a clone of the element with a different parent.
     */
  
negative.code:   }
  
    /** Returns all interfaces implemented by this class. */
    List<ClassElement> get interfaces {
      if (_interfaces == null) {
        final allInterfaces = new Set<ClassElement>();
        final superclassSet = superclasses.toSet();
       
        addInterface(ClassElement ref) {
          if (!superclassSet.contains(ref)) {
            allInterfaces.add(ref);
          }
        }
        addInterfaces(Iterable<ClassElement> refs) {
          for(var ref in refs) {
            addInterface(ref);
          }
  