@Nullable
  private static <T extends RegExpElement> T findElementAtStrict(PsiFile file, int startOffset, int endOffset, Class<T> clazz) {
    T element = PsiTreeUtil.findElementOfClassAtRange(file, startOffset, endOffset, clazz);
    if (element == null || element.getTextRange().getEndOffset() < endOffset) return null;
    return element;
  }
@Nullable
  private static <T extends RegExpElement> T findElementAtStrict(PsiFile file, int startOffset, int endOffset, Class<T> clazz)