// returns true if it worked ok
static bool expandEllipsis(OccTree2 tree) {
  bool ok = true;
  OccTree2 node = null;
  int safety = 0;
  while (++safety < 1000 && (node = findNode(tree, E.state("..."))) != null) {
    OccTree2 p = node.parent;
    L<OccTree2> l = findNodes(tree, p.e);
    l.remove(p);
    if (empty(l)) {
      print("Couldn't expand ellipsis after " + p.e);
      ok = false;
    }
    p.replaceWith(cloneOccTree(first(l)));
  }
  if (node != null) {
    print("Expand ellipsis: Warning - Safety count reached (" + safety + ")");
    ok = false;
  }
  ret ok;
}