#![allow(dead_code, deprecated, unused_variables, unused_mut)]
fn main() {
    let s: Option<String> = Some(String::from("Hello, Rustaceans!"));
    let o: Option<usize> = Option::from(&s).map(|ss: &String| ss.len());
    println!("Can still print s: {s:?}");
    assert_eq!(o, Some(18));
}