static boolean matchEnd(S pat, S s) {
  return matchEnd(pat, s, null);
}

// matches are as you expect, plus an extra item for the rest string
static boolean matchEnd(S pat, S s, Matches matches) {
  if (s == null) false;
  L<S> tokpat = parse3(pat), toks = parse3(s);
  if (toks.size() < tokpat.size()) false;
  S[] m = match2(tokpat, takeLast(l(tokpat), toks));
  if (m == null) false;
  if (matches != null) {
    matches.m = new S[m.length+1];
    arraycopy(m, matches.m);
    matches.m[m.length] = join(dropLast(l(tokpat), toks)); // for Matches.rest()
  }
  true;
}

Began life as a copy of #1001793