static L<PTElement> ai_scanParseTreeForWord_all_tighter(PTElement e, S word) {
  new L<PTElement> out;
  ai_scanParseTreeForWord_all_tighter_scan(e, word, out);
  ret out;
}

svoid ai_scanParseTreeForWord_all_tighter_scan(PTElement e, S word, L<PTElement> out) {
  if (e == null) ret;
  if (!(e instanceof HaveCategory && nempty(e.children)) && eqic(e.text(), word)) ret with out.add(e);
  for (PTElement child : unnull(e.children))
    ai_scanParseTreeForWord_all_tighter_scan(child, word, out);
}

Began life as a copy of #1017492