anchor.diff:        {RunOptions? runOptions, String? workingDirectory}) {
       runOptions = mergeWorkingDirectory(workingDirectory, runOptions);
       return runlib
  -        .runAsync(sdkBin('pub'),
  -            arguments: ['downgrade'], runOptions: runOptions)
  +        .runAsync(sdkBin('dart'),
  +            arguments: ['pub', 'downgrade'], runOptions: runOptions)
           .then((_) => null);
     }
   
  
positive.code:       String? workingDirectory}) {
      runOptions = mergeWorkingDirectory(workingDirectory, runOptions);
      var scriptArg = script == null ? package : '$package:$script';
      final args = ['global', 'run', scriptArg];
      if (arguments != null) args.addAll(arguments);
      return runlib.run(sdkBin('pub'), arguments: args, runOptions: runOptions);
    }
  
    /// Run the given installed Dart application.
    Future<String> runAsync(String package,
        {List<String>? arguments, RunOptions? runOptions, String? script}) {
      var scriptArg = script == null ? package : '$package:$script';
      final args = ['global', 'run', scriptArg];
      if (arguments != null) args.addAll(arguments);
      return runlib.runAsync(sdkBin('pub'),
          arguments: args, runOptions: runOptions);
    }
  
  
negative.code:   /// Install a new Dart application.
    void activate(String packageName, {bool force = false}) {
      if (force || !isActivated(packageName)) {
        runlib.run(sdkBin('dart'), arguments: ['pub', 'global', 'activate', packageName]);
        _activatedPackages.add(packageName);
      }
    }
  