#![allow(dead_code, deprecated, unused_variables, unused_mut)]
fn main() {
    let slice = &mut [1, 2, 3];
    let mut iter = slice.iter_mut();
    println!("{:?}", iter.as_slice());
    *iter.next().unwrap() += 1;
    println!("{:?}", iter.as_slice());
    println!("{:?}", slice);
}