@Override
  final @NotNull List<StubElement<?>> getPlainListFromAllRoots() {
    PsiFileStub<?>[] roots = ((PsiFileStubImpl<?>)getRoot()).getStubRoots();
    if (roots.length == 1) return super.getPlainListFromAllRoots();

    return ContainerUtil.concat(roots, stub -> ((PsiFileStubImpl<?>)stub).myStubList.toPlainList());
  }
@Override
  final @NotNull List<StubElement<?>> getPlainListFromAllRoots()