#![allow(dead_code, deprecated, unused_variables, unused_mut)]
#![feature(iter_intersperse)]
fn main() {
    let src = ["Hello", "to", "all", "people", "!!"].iter().copied();
    let mut happy_emojis = [" ❤️ ", " 😀 "].into_iter();
    let separator = || happy_emojis.next().unwrap_or(" 🦀 ");
    let result = src.intersperse_with(separator).collect::<String>();
    assert_eq!(result, "Hello ❤️ to 😀 all 🦀 people 🦀 !!");
}