anchor.diff:     */
     TaskManager get taskManager {
       if (_taskManager == null) {
  -      if (enginePlugin.taskExtensionPoint == null) {
  -        // The plugin wasn't used, so tasks are not registered.
  -        new ExtensionManager().processPlugins([enginePlugin]);
  -      }
  +      new ExtensionManager().processPlugins(supportedPlugins);
         _taskManager = new TaskManager();
         _taskManager.addTaskDescriptors(enginePlugin.taskDescriptors);
         // TODO(brianwilkerson) Create a way to associate different results with
  
positive.code:   bool limitInvalidationInTaskModel = false;
  
    /**
     * The task manager used to manage the tasks used to analyze code.
     */
    TaskManager _taskManager;
  
negative.code:       _taskManager.addGeneralResult(DART_ERRORS);
      }
      return _taskManager;
    }
  
    /**
     * Set plugins that are defined outside the `analyzer` package.
     */
    void set userDefinedPlugins(List<Plugin> plugins) {
      if (plugins == null) {
        plugins = <Plugin>[];
      }
      _userDefinedPlugins = plugins;
      _supportedPlugins = null;
      _taskManager = null;
    }
  
    /**
  