anchor.diff:    }
   }
   
  -class JavaScriptionResolutionCallbacks extends ResolutionCallbacks {
  +class JavaScriptResolutionCallbacks extends ResolutionCallbacks {
     final JavaScriptBackend backend;
   
  -  JavaScriptionResolutionCallbacks(this.backend);
  +  JavaScriptResolutionCallbacks(this.backend);
   
     void registerBackendStaticInvocation(Element element, Registry registry) {
       registry.registerStaticInvocation(backend.registerBackendUse(element));
  
positive.code:     typeVariableHandler = new TypeVariableHandler(this);
      customElementsAnalysis = new CustomElementsAnalysis(this);
      constantCompilerTask = new JavaScriptConstantTask(compiler);
      resolutionCallbacks = new JavaScriptionResolutionCallbacks(this);
    }
  
    ConstantSystem get constantSystem => constants.constantSystem;
  
negative.code: 
    JavaScriptConstantTask constantCompilerTask;
  
    JavaScriptResolutionCallbacks resolutionCallbacks;
  
    JavaScriptBackend(Compiler compiler, bool generateSourceMap)
        : namer = determineNamer(compiler),
  