static L mapNonNulls(Iterable l, O f) { ret mapNonNulls(f, l); }

static L lambdaMapLike mapNonNulls(O f, Iterable l) {
  new L x;
  if (l != null) for (O o : l)
    addIfNotNull(x, callF(f, o));
  ret x;
}

static L mapNonNulls(O f, O[] l) {
  new L x;
  if (l != null) for (O o : l)
    addIfNotNull(x, callF(f, o));
  ret x;
}

ifclass F1
  static <A, B> L<B> mapNonNulls(Iterable<A> l, F1<A, B> f) { ret mapNonNulls(f, l); }

  static <A, B> L<B> mapNonNulls(F1<A, B> f, Iterable<A> l) {
    new L x;
    if (l != null) for (O o : l)
      addIfNotNull(x, callF(f, o));
    ret x;
  }
endif

static <A, B> L<B> mapNonNulls(A[] l, IF1<A, B> f) {
  ret mapNonNulls(f, l);
}

static <A, B> L<B> mapNonNulls(Iterable<A> l, IF1<A, B> f) {
  L x = emptyList(l);
  if (l != null) for (A o : l)
    addIfNotNull(x, f.get(o));
  ret x;
}

static <A, B> L<B> mapNonNulls(IF1<A, B> f, Iterable<A> l) {
  ret mapNonNulls(l, f);
}

Began life as a copy of #1003239