anchor.diff:        return _kernel.documentationComment;
       }
       if (serializedExecutable != null) {
  -      return serializedExecutable?.documentationComment?.text;
  +      return serializedExecutable.documentationComment?.text;
       }
       return super.documentationComment;
     }
  
positive.code:   @override
    String get documentationComment {
      if (_unlinkedTypedef != null) {
        return _unlinkedTypedef?.documentationComment?.text;
      }
      return super.documentationComment;
    }
  
negative.code:   @override
    String get documentationComment {
      if (_unlinkedTypedef != null) {
        return _unlinkedTypedef.documentationComment?.text;
      }
      return super.documentationComment;
    }
  