type Point {
    x: i32,
    y: i32,
}

fn bump(p: mutref<Point>) -> Void {
    p.x = p.x + 1
    p.y = p.y + 2
}

fn sum(p: ref<Point>) -> i32 {
    return p.x + p.y
}

pub fn main(world: World) -> Void raises {
    var pt: Point = Point { x: 1, y: 2 }
    bump(&mut pt)
    if pt.x == 2 {
        check world.out.write("mutref x ok\n")
    }
    if pt.y == 4 {
        check world.out.write("mutref y ok\n")
    }
    if sum(&pt) == 6 {
        check world.out.write("ref sum ok\n")
    }
}