fn compute1() -> float {
    let v = ~[0f, 1f, 2f, 3f];

    do vec::foldl(0f, v) |x, y| { x + *y } - 10f
    //~^ ERROR mismatched types: expected `()`
}

fn main() {
    let x = compute1();
    log(debug, x);
    assert(x == -4f);
}