static LinkedHashSet mapToLinkedHashSet(O f, Cl l) {
  LinkedHashSet x = new(l(l));
  if (l != null) for (O o : l)
    x.add(callF(f, o));
  ret x;
}
static LinkedHashSet mapToLinkedHashSet(O f, Iterable l) {
  new LinkedHashSet x;
  if (l != null) for (O o : l)
    x.add(callF(f, o));
  ret x;
}

static <A, B> LinkedHashSet<B> lambdaMapLike mapToLinkedHashSet(IF1<A, B> f, Iterable<A> l) {
  ret mapToLinkedHashSet((O) f, l);
}

Began life as a copy of #1011181