anchor.diff:        _writeNodeList(const <ConstructorInitializer>[]);
       }
   
  -    if (_shouldWriteResolution) {
  -      _resolutionSink!.localElements.popScope();
  +    if (resolutionSink != null) {
  +      resolutionSink.localElements.popScope();
       }
   
       _writeMarker(MarkerTag.ConstructorDeclaration_redirectedConstructor);
  
positive.code:         isAbstract: node.abstractKeyword != null,
        ),
      );
      if (_shouldWriteResolution) {
        _resolutionSink!.writeByte(node.declaredElement!.isSimplyBounded ? 1 : 0);
      }
      _writeInformativeUint30(node.offset);
      _writeInformativeUint30(node.length);
      _pushScopeTypeParameters(node.typeParameters);
  
negative.code:     );
      _writeDeclarationName(node.name);
  
      var resolutionSink = _resolutionSink;
      if (resolutionSink != null) {
        // TODO(scheglov) Enforce not null, remove `?` in `?.type` below.
        var element = node.declaredElement as VariableElementImpl;
        _writeMarker(MarkerTag.VariableDeclaration_type);
        _writeActualType(resolutionSink, element.type);
        _writeMarker(MarkerTag.VariableDeclaration_inferenceError);
        _writeTopLevelInferenceError(resolutionSink, element);
        if (element is FieldElementImpl) {
          _writeMarker(MarkerTag.VariableDeclaration_inheritsCovariant);
          resolutionSink.writeByte(element.inheritsCovariant ? 1 : 0);
        }
      }
  
  