private static int lastUnescapedIndexOf(@NotNull String s, int from, char c) {
    int result = from;

    do {
      result = s.lastIndexOf(c, result - 1);
    }
    while (result != -1 && !isUnescaped(s, result, c));

    return result;
  }
private static int lastUnescapedIndexOf(@NotNull String s, int from, char c)