void (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); } }