anchor.diff:    TypeParameter._();
   
     factory TypeParameter([updates(TypeParameterBuilder b)]) = _$TypeParameter;
  -
  -  factory TypeParameter.build(
  -      {String docComment, String name, Classifier bound}) {
  -    return (new TypeParameterBuilder()
  -          ..docComment = docComment
  -          ..name = name
  -          ..bound = bound)
  -        .build();
  -  }
   }
   
   abstract class TypeParameterBuilder
  
positive.code:   Property._();
  
    factory Property([updates(PropertyBuilder b)]) = _$Property;
  
    factory Property.build(
        {String docComment,
        String name,
        Classifier type,
        bool isNullable,
        Object defaultValue,
        String derivedExpression}) {
      return (new PropertyBuilder()
            ..docComment = docComment
            ..name = name
            ..type = type
            ..isNullable = isNullable ?? false
            ..defaultValue = defaultValue
            ..derivedExpression = derivedExpression)
          .build();
    }
  }
  
  abstract class PropertyBuilder implements Builder<Property, PropertyBuilder> {
  
negative.code:   ExternalClass._();
  
    factory ExternalClass([updates(ExternalClassBuilder b)]) = _$ExternalClass;
  }
  
  abstract class ExternalClassBuilder
  