anchor.diff:     * Perform work until the given [result] has been computed for the given
      * [target]. Return the computed value.
      */
  -  Object /*V*/ computeResult(AnalysisTarget target, ResultDescriptor /*<V>*/ result);
  +  Object /*V*/ computeResult(
  +      AnalysisTarget target, ResultDescriptor /*<V>*/ result);
   
     /**
      * Notifies the context that the client is going to stop using this context.
  
positive.code:         commandLinePlugin,
          optionsPlugin
        ];
      }
      return _supportedPlugins;
    }
  
negative.code:   bool limitInvalidationInTaskModel = false;
  
    /**
     * The plugins that are defined outside the `analyzer` package.
     */
    List<Plugin> _userDefinedPlugins = <Plugin>[];
  
    /**
     * The task manager used to manage the tasks used to analyze code.
     */
    TaskManager _taskManager;
  