anchor.diff:  part 'model.g.dart';
   
   abstract class ModelElement {
  +  @nullable
     String get docComment;
   }
   
  
positive.code: 
  abstract class TypeParameterBuilder
      implements Builder<TypeParameter, TypeParameterBuilder> {
    String name;
    @nullable
    Classifier bound;
  
negative.code:     implements Built<Property, PropertyBuilder>, NamedElement {
    static final Serializer<Property> serializer = _$propertySerializer;
  
    @nullable
    String get docComment;
    String get name;
    Classifier get type;
    bool get isNullable;
  