@NotNull
  static String convertRegExpTypeToTypeString(@NotNull String regexp) {
    final StringBuilder result = new StringBuilder();
    for (int i = 0, length = regexp.length(); i < length; i++) {
      final int c = regexp.codePointAt(i);
      if (c == '.') {
        if (i == length - 1 || !MatchUtil.isRegExpMetaChar(regexp.codePointAt(i + 1))) {
          result.append('.'); // consider dot not followed by other meta char a mistake
        }
        else {
          return ""; // can't convert
        }
      }
      else if (c == '|') {
        result.append('|');
      }
      else if (c == '\\') {
        if (i + 1 < length) {
          result.appendCodePoint(regexp.codePointAt(i + 1));
          i++;
        }
        else {
          result.append('\\');
        }
      }
      else if (c == ']') {
        result.append(']');
      }
      else if (c == '(' || c == ')') {
        // do nothing
      }
      else if (MatchUtil.isRegExpMetaChar(c)) {
        return ""; // can't convert
      }
      else {
        result.appendCodePoint(c);
      }
    }
    return result.toString();
  }
@NotNull
  static String convertRegExpTypeToTypeString(@NotNull String regexp)