#[derive(Debug)]
struct Foo(u32);


impl Foo {
    fn succ(self) -> Self {
        Self(self.0 + 1)
    }
}

fn main() {
    (0..4).fold(
        Foo(0),
        |f, _| {
            println!("{:?}",f);
            f.succ()
        },
    );
}