static <A> A listGetOrCreate_full(L<A> l, int i, Class<? extends A> c) {
  if (l == null) null;
  while (i >= l(l))
    l.add(nuInstance(c));
  ret l.get(i);
}

static <A> A nuLike listGetOrCreate_full(Class<? extends A> c, L<A> l, int i) {
  ret listGetOrCreate_full(l, i, c);
}

Began life as a copy of #1022705