anchor.diff:          args.add('--no-background-compilation');
         }
       } else {
  +      args.add('--no-preview-dart-2');
         if (_isStrong) {
           args.add('--strong');
         }
  
positive.code:     }
      if (useDfe) {
        args.add('--preview-dart-2');
      }
      args
        ..addAll(vmOptions)
  
negative.code:       args.add('--preview-dart-2');
        args.addAll(_replaceDartFiles(arguments, tempKernelFile(tempDir)));
      } else {
        args.add('--no-preview-dart-2');
        args.addAll(arguments);
      }
  
  