4 #![allow(incomplete_features)]
7 fn add1(&mut self) -> usize;
10 impl AddOne for usize {
11 fn add1(&mut self) -> usize {
17 impl AddOne for &mut usize {
18 fn add1(&mut self) -> usize {
23 fn add_one(mut i: dyn* AddOne + '_) -> usize {
29 let y = &mut x as (dyn* AddOne + '_);
31 println!("{}", add_one(y));