anchor.diff:        args.add('--strong');
       }
       if (previewDart2) {
  -      args.add('--preview-dart-2');
         args.addAll(_replaceDartFiles(arguments, tempKernelFile(tempDir)));
       } else {
         args.add('--no-preview-dart-2');
  
positive.code:       CommandArtifact artifact) {
      var args = <String>[];
      if (previewDart2) {
        args.add('--preview-dart-2');
        if (_isChecked) {
          args.add('--enable_asserts');
        }
  
negative.code:     var exec = "${_configuration.buildDirectory}/dart";
      var snapshot = "$tempDir/out.jitsnapshot";
      var args = ["--snapshot=$snapshot", "--snapshot-kind=app-jit"];
      if (!previewDart2) {
        args.add("--no-preview-dart-2");
      }
      args.addAll(arguments);
  