static <A> A assertNotNull(A a) {
  assertTrue(a != null);
  ret a;
}

static <A> A assertNotNull(S msg, A a) {
  assertTrue(msg, a != null);
  ret a;
}

ifclass Scorer
static <A> A assertNotNull(Scorer scorer, S msg, A a) {
  if (scorer == null) ret assertNotNull(msg, a);
  if (a == null) {
    print("BAD - " + msg + " is null: " + a);
    scorer.add(false);
  } else {
    print("OK, " + msg + " not null: " + a);
    scorer.add(true);
  }
  ret a;
}
endif

Began life as a copy of #1001598