anchor.diff:  
     if (autoIdAndDateFields != false) {
       if (!fieldNames.contains('id')) {
  -      var idField = new _ShimField('id', lib.context.typeProvider.stringType);
  +      var idField = new ShimFieldImpl('id', lib.context.typeProvider.stringType);
         ctx.fields.insert(0, idField);
         ctx.shimmed['id'] = true;
       }
  
positive.code: const TypeChecker serializableTypeChecker =
      const TypeChecker.fromRuntime(Serializable);
  
  // TODO: Should add id, createdAt, updatedAt...
  Future<BuildContext> buildContext(
      ClassElement clazz,
      Serializable annotation,
  
negative.code:           dateTime = dt.type;
          }
  
          var field = new ShimFieldImpl(key, dateTime);
          ctx.aliases[key] = new ReCase(key).snakeCase;
          ctx.fields.add(field);
          ctx.shimmed[key] = true;
  