static S assertEqualsVerbose_match(S x, S y) {
  assertEqualsVerbose_match((S) null, x, y);
  ret y;
}

static S assertEqualsVerbose_match(S msg, S x, S y) {
  if (!match(x, y)) {
    fail((msg != null ? msg + ": " : "") + quote(y) + " != " + quote(x));
  } else
    print("OK: " + quote(x));
  ret y;
}