@Override
  public final @NotNull List<FileASTNode> getKnownTreeRoots() {
    PsiFile psiFile = getCachedPsi(getBaseLanguage());
    if (!(psiFile instanceof PsiFileImpl)) return Collections.emptyList();
    FileASTNode element = ((PsiFileImpl)psiFile).getNodeIfLoaded();
    return ContainerUtil.createMaybeSingletonList(element);
  }
@Override
  public final @NotNull List<FileASTNode> getKnownTreeRoots()