static boolean stdEq2(O a, O b) {
  if (a == null) ret b == null;
  if (b == null) ret false;
  if (a.getClass() != b.getClass()) ret false;
  for (S field : allFields(a))
    if (neq(getOpt(a, field), getOpt(b, field)))
      ret false;
  ret true;
}