@Override
  public PsiFile @NotNull [] getPsiRoots() {
    FileViewProvider viewProvider = getViewProvider();
    Set<Language> languages = viewProvider.getLanguages();

    PsiFile[] roots = new PsiFile[languages.size()];
    int i = 0;
    for (Language language : languages) {
      PsiFile psi = viewProvider.getPsi(language);
      if (psi == null) {
        LOG.error("PSI is null for "+language+"; in file: "+this);
      }
      roots[i++] = psi;
    }
    if (roots.length > 1) {
      Arrays.sort(roots, FILE_BY_LANGUAGE_ID);
    }
    return roots;
  }
@Override
  public PsiFile @NotNull [] getPsiRoots()