# 高阶特征约束(HRTB) todo https://www.reddit.com/r/rust/comments/s6g16d/help_with_hrtb_lifetimes/ ## for<'a> https://www.reddit.com/r/rust/comments/rq43c6/generic_fn_impl_for_iterating_over_mut_items_twice/ https://www.reddit.com/r/rust/comments/6uobit/fora_lifetime_syntax/