#![allow(dead_code, deprecated, unused_variables, unused_mut)]
fn main() {
    let mut chars = "a楽".char_indices();
    assert_eq!(chars.offset(), 0);
    assert_eq!(chars.next(), Some((0, 'a')));
    assert_eq!(chars.offset(), 1);
    assert_eq!(chars.next(), Some((1, '楽')));
    assert_eq!(chars.offset(), 4);
    assert_eq!(chars.next(), None);
}