@Override
    public void visitRegExpClass(RegExpClass regExpClass) {
      PsiFile file = regExpClass.getContainingFile();
      if (file == null || Boolean.TRUE.equals(file.getUserData(InjectedLanguageUtil.FRANKENSTEIN_INJECTION))) return;
      final HashSet<Object> seen = new HashSet<>();
      for (RegExpClassElement element : regExpClass.getElements()) {
        checkForDuplicates(element, seen);
      }
    }
@Override
    public void visitRegExpClass(RegExpClass regExpClass)