@Nullable
  private PsiType inferClosureReturnType() {
    final ExtractClosureHelperImpl mockHelper =
      new ExtractClosureHelperImpl(myInfo, "__test___n_", false, new IntArrayList(), false,
                                   IntroduceParameterRefactoring.REPLACE_FIELDS_WITH_GETTERS_NONE, false, false, false);
    return WriteAction.compute(() -> ExtractClosureProcessorBase.generateClosure(mockHelper).getReturnType());
  }
@Nullable
  private PsiType inferClosureReturnType()