private static @Nullable String getInfix(String currentPrefix, String className) {
    if (!currentPrefix.startsWith(className)) return null;
    for (String infix : new String[]{".", "#", "::"}) {
      if (currentPrefix.startsWith(infix, className.length())) {
        return infix;
      }
    }
    return null;
  }
private static @Nullable String getInfix(String currentPrefix, String className)