anchor.diff:        this._directory, this._pathContext, this._logger, this._processManager);
   
     bool check() {
  -    var pubPath = _pathContext.join(getSdkPath(), 'bin', _pubName);
  -    var result = _processManager.runSync(
  -        pubPath, ['outdated', '--mode=null-safety', '--json'],
  -        workingDirectory: _directory);
  -
  +    var pubPath = _pathContext.join(getSdkPath(), 'bin', 'dart');
  +    var pubArguments = ['pub', 'outdated', '--mode=null-safety', '--json'];
       var preNullSafetyPackages = <String, String>{};
       try {
  +      var result = _processManager.runSync(pubPath, pubArguments,
  +          workingDirectory: _directory);
         if ((result.stderr as String).isNotEmpty) {
           throw FormatException(
  -            '`pub outdated --mode=null-safety` exited with exit code '
  +            '`dart pub outdated --mode=null-safety` exited with exit code '
               '${result.exitCode} and stderr:\n\n${result.stderr}');
         }
         var outdatedOutput = jsonDecode(result.stdout as String);
  
positive.code:         var version = json.expectType<String>(current['version'], 'version');
          preNullSafetyPackages[name] = version;
        }
      } on FormatException catch (e) {
        _logger.stderr('Warning: ${e.message}');
        // Allow the program to continue; users should be allowed to attempt to
  
negative.code:       }
        _logger.stderr('');
        _logger.stderr('It is highly recommended to upgrade all dependencies to '
            'versions which have migrated. Use `dart pub outdated '
            '--mode=null-safety` to check the status of dependencies.');
        _logger.stderr('');
        _logger.stderr('Visit https://dart.dev/tools/pub/cmd/pub-outdated for '
  