struct Returner {
    val: i32,
}

impl<'a> Returner {
    fn get(&'a self) -> Box<Fn(i32) -> i32> {
        Box::new(|x| x + self.val)
    }
}

struct Returner {
    val: i32,
}

impl<'a> Returner {
    fn get(&'a self) -> Box<(Fn(i32) -> i32) + 'a> {
        return Box::new(move |x| x + self.val);
    }
}