public static @NotNull List<ID<?, ?>> getNontrivialFileIndexedStates(int fileId) {
    return ourLock.withReadLock(fileId, () -> {
      try {
        Timestamps stamp = createOrGetTimeStamp(fileId);
        if (stamp.hasIndexingTimeStamp()) {
          return List.copyOf(stamp.getIndexIds());
        }
      }
      catch (InvalidVirtualFileAccessException ignored /*ok to ignore it here*/) {
      }
      return Collections.emptyList();
    });
  }
public static @NotNull List<ID<?, ?>> getNontrivialFileIndexedStates(int fileId)