@Override
  public @NotNull <K, V> Collection<VirtualFile> getContainingFiles(@NotNull ID<K, V> indexId,
                                                                    @NotNull K dataKey,
                                                                    @NotNull GlobalSearchScope filter) {
    Collection<VirtualFile> scanResult = FileBasedIndexScanUtil.getContainingFiles(indexId, dataKey, filter);
    if (scanResult != null) return scanResult;
    return super.getContainingFiles(indexId, dataKey, filter);
  }
@Override
  public @NotNull <K, V> Collection<VirtualFile> getContainingFiles(@NotNull ID<K, V> indexId,
                                                                    @NotNull K dataKey,
                                                                    @NotNull GlobalSearchScope filter)