anchor.diff:      _storeNormalFormalParameter(node, null);
       _writeMarker(MarkerTag.FunctionTypedFormalParameter_end);
   
  -    if (_shouldWriteResolution) {
  -      _resolutionSink!.localElements.popScope();
  +    var resolutionSink = _resolutionSink;
  +    if (resolutionSink != null) {
  +      resolutionSink.localElements.popScope();
       }
     }
   
  
positive.code:   void _storeForLoopParts(ForLoopParts node) {}
  
    void _storeFormalParameter(FormalParameter node) {
      if (_shouldWriteResolution) {
        _writeMarker(MarkerTag.FormalParameter_type);
        _writeActualType(node.declaredElement!.type);
      }
    }
  
  
negative.code:       _writeNodeList(const <ConstructorInitializer>[]);
      }
  
      if (resolutionSink != null) {
        resolutionSink.localElements.popScope();
      }
  
      _writeMarker(MarkerTag.ConstructorDeclaration_redirectedConstructor);
  