anchor.diff:  
   abstract class GenericTypeBuilder
       implements Builder<GenericType, GenericTypeBuilder> {
  +  @nullable
  +  String docComment;
     String name;
     Classifier base;
     MapBuilder<TypeParameter, Classifier> genericTypeValues =
  
positive.code: }
  
  abstract class PropertyBuilder implements Builder<Property, PropertyBuilder> {
    String name;
    Classifier type;
    bool isNullable = false;
  
negative.code: 
  abstract class TypeParameterBuilder
      implements Builder<TypeParameter, TypeParameterBuilder> {
    @nullable
    String docComment;
    String name;
    @nullable
    Classifier bound;
  