extern mod std;

fn main() {
    let v =
        vec::map2(~[1, 2, 3, 4, 5],
                  ~[true, false, false, true, true],
                  |i, b| if *b { -(*i) } else { *i } );
    log(error, copy v);
    assert (v == ~[-1, 2, 3, -4, -5]);
}