#![allow(unused)]
use std::cmp;

#[derive(Debug)]
enum Foo {
    Bar(Option<u8>),
}

fn main() {
    let mut foo = Foo::Bar(Some(10));
    match &mut foo {
        &mut Foo::Bar(ref mut optional) => match optional {
            &mut Some(ref mut o) => {
                *o = 55;
            }
            _ => {},
        }
        _ => {}
    };
    println!("{:?}", foo);


    let mut foo = Foo::Bar(Some(10));
    match &mut foo {
        Foo::Bar(optional) => match optional {
            Some(o) => {
                *o = 55;
            }
            _ => {},
        }
        _ => {}
    };
    println!("{:?}", foo);
}