// borrow.bux — Test explicit borrow expressions

struct Point {
	x: int;
	y: int;
}

// NOT @[Checked] — borrow keyword available everywhere
func MovePoint(p: *Point) {
    let ref: &Point = borrow &p;
    let x: int = (*ref).x;
}

// @[Checked] enables borrow protection
@[Checked]
func SwapPoints(a: *Point, b: *Point) {
    let ra: &mut Point = borrow &mut a;
    let rb: &mut Point = borrow &mut b;
    let tmp: int = (*ra).x;
    (*ra).x = (*rb).x;
    (*rb).x = tmp;
}

func Main() -> int {
    var p1: Point;
    p1.x = 10;
    p1.y = 20;
    var p2: Point;
    p2.x = 30;
    p2.y = 40;
    SwapPoints(&p1, &p2);
    return 0;
}