static SS gazelle_deepZip_keepBrackets(S inputA, S inputB, O... _) {
  SS map = gazelle_zip_keepBrackets(inputA, inputB);
  if (map == null) null;
  SS map2 = similarEmptyMap(map);
  for (S a, S b : map) {
    bool iba = tok_isRoundOrCurlyBracketed(a), ibb = tok_isRoundOrCurlyBracketed(b);
    if (iba && ibb) {
      S aa = tok_deRoundOrCurlyBracket(a);
      S bb = tok_deRoundOrCurlyBracket(b);
      SS subMap = gazelle_deepZip_keepBrackets(aa, bb, _);
      if (subMap == null) null;
      if (!putAllStrictlyIC(map2, subMap)) null;
    } else if (eqic_roundBracketed(a, b)) {
      // OK, match
    } else
      if (!strictPutIC(map2, a, b)) null;
  }
  ret map2;
}

Began life as a copy of #1025728