fn main() {
    #[derive(Clone, Copy)]
struct Point {
    x: f64,
    y: f64,
}
let p1 = Point {
    x: 1.0,
    y: 2.0,
};
let p2 = Point {
    x: 2.0,
    ..p1,
};
assert_eq!(p2.x, p2.y);
}