static GazelleTree gazelle_searchTreeUpwards(F1<GazelleTree, Bool> pred, GazelleTree tree) {
  L<GazelleTree> l = gazelle_treeAsListUpTo(tree);
  for (int i = l(l)-1; i >= 0; i--)
    if (isTrue_callF(l.get(i)))
      ret l.get(i);
  null;
}