anchor.diff:    }
   
     compiler ??= _FlutterFrontendCompiler(output,
  -      transformer: frontend.ToStringTransformer(transformer, deleteToStringPackageUris),
  +      transformer: handleDeleteToString
  +          ? frontend.ToStringTransformer(transformer, deleteToStringPackageUris)
  +          : null,
         useDebuggerModuleNames: options['debugger-module-names'] as bool,
         emitDebugMetadata: options['experimental-emit-debug-metadata'] as bool,
         unsafePackageSerialization:
  
positive.code:     return 1;
    }
  
    final Set<String> deleteToStringPackageUris = (options['delete-tostring-package-uri'] as List<String>).toSet();
  
    if (options['train'] as bool) {
      if (!options.rest.isNotEmpty) {
  
negative.code:   frontend.ProgramTransformer transformer,
  }) async {
    ArgResults options;
    // TODO(alexmarkov): Remove handling of --delete-tostring-package-uri option
    //  after it is added to Dart SDK,
    //  https://github.com/dart-lang/sdk/issues/46022.
    final bool handleDeleteToString =
        !frontend.argParser.options.containsKey('delete-tostring-package-uri');
    if (handleDeleteToString) {
      frontend.argParser.addMultiOption(
        'delete-tostring-package-uri',
        help:
            'Replaces implementations of `toString` with `super.toString()` for '
            'specified package',
        valueHelp: 'dart:ui',
        defaultsTo: const <String>[],
      );
    }
    try {
      options = frontend.argParser.parse(args);
    } catch (error) {
  