// f: A -> Comparable
static <A> L<A> sortInPlaceByCalculatedFieldDesc_f1(L<A> l, final F1<A, ?> f) {
  sort(l, new Comparator<A>() {
    public int compare(A a, A b) {
      ret stdcompare(f.get(b), f.get(a));
    }
  });
  ret l;
}