static <A> ArrayList<Long> longArrayToList(long[] a) {
  if (a == null) null;
  ret longArrayToList(a, 0, a.length);
}

// no range checking on from/to in the interest of S P E E E E E EEED
static <A> ArrayList<Long> longArrayToList(long[] a, int from, int to) {
  if (a == null) null;
  ArrayList<Long> l = new(to-from);
  for (int i = from; i < to; i++) l.add(a[i]);
  ret l;
}

Began life as a copy of #1025516