message: fix another crash related with
diff: @@ -205,7 +205,10 @@ static expr preprocess(Transform &t, const set<expr> &qvars,
  expr nums[3] = { expr::mkUInt(0, 2), expr::mkUInt(1, 2), expr::mkUInt(2, 2) };
  for (auto &i : t.src.getInputs()) {
  - auto var = static_cast<const Input&>(i).getTyVar();
  + auto in = dynamic_cast<const Input*>(&i);
  + if (!in)
  + continue;
  + auto var = in->getTyVar();
  for (auto &[e, v] : instances) {
  for (unsigned i = 0; i <= 2; ++i) {
  