static LPair<ListWithFeedback, WithFeedback<Proposition>> ai_findConfirmedPropositionsWithPattern(S pat) {
  new LPair<ListWithFeedback, WithFeedback<Proposition>> out;
  for (File f : listFilesWithExtension(".struct", ai_listsWithFeedbackDir())) pcall {
    ListWithFeedback list = ai_loadListWithFeedback(f);
    fOr (WithFeedback<WithReasoning<S>> entry : list.data) {
      if (!startsWithPlus(entry.feedback)) continue;
      Proposition p = entry!;
      if (match(pat, p!))
        out.add(pair(list, entry));
    }
  }
  ret out;
}