anchor.diff:  }
   
   abstract class TypeParameter
  -    implements NamedElement, Built<TypeParameter, TypeParameterBuilder> {
  +    implements Built<TypeParameter, TypeParameterBuilder>, NamedElement {
     static final Serializer<TypeParameter> serializer = _$typeParameterSerializer;
     String get name;
     @nullable
  
positive.code: }
  
  abstract class GenericType
      implements Classifier, Built<GenericType, GenericTypeBuilder> {
    static final Serializer<GenericType> serializer = _$genericTypeSerializer;
    String get name;
    Classifier get base;
  
negative.code:   factory TypeParameterBuilder() = _$TypeParameterBuilder;
  }
  
  abstract class Property
      implements Built<Property, PropertyBuilder>, NamedElement {
    static final Serializer<Property> serializer = _$propertySerializer;
    String get name;
    Classifier get type;
  