#![allow(unused_variables)]
fn main() {
    use std::collections::VecDeque;
    let mut buf = VecDeque::new();
    buf.push_back(5);
    buf.push_back(3);
    buf.push_back(4);
    for num in buf.iter_mut() {
        *num = *num - 2;
    }
    let b: &[_] = &[&mut 3, &mut 1, &mut 2];
    assert_eq!(& buf.iter_mut().collect::< Vec <& mut i32 >> () [..], b);
}