anchor.diff:        : super(element, library);
   
     bool get isGetter => _accessor.isGetter;
  +
  +  @override
  +  String get _href => throw "not implemented yet";
   }
   
   /// Top-level variables. But also picks up getters and setters?
  
positive.code: class Dynamic extends ModelElement {
    Dynamic(DynamicElementImpl element, Library library, [String source])
        : super(element, library, source);
  }
  
  class Package {
  
negative.code:   ElementType get type => new ElementType(_typeParameter.type, library);
  
    String toString() => element.name;
  
    @override
    String get _href => throw 'not implemented yet';
  }
  
  class ElementType {
  