#![allow(dead_code, deprecated, unused_variables, unused_mut)]
use std::iter::Chain;
use std::slice::Iter;
fn main() {
    let a1 = [1, 2, 3];
    let a2 = [4, 5, 6];
    let iter: Chain<Iter<'_, _>, Iter<'_, _>> = a1.iter().chain(a2.iter());
}