All of those unsafe "hole fixes" are features, meaning your desires are for adding even more features. Additionally, useful back pointer support (i.e. for anyt

All of those unsafe "hole fixes" are features, meaning your desires are for adding even more features. Additionally, useful back pointer support (i.e. for anything more than a toy doubly linked list) is probably a bigger feature than anything else added since Rust 1.0, and probably harder to work with.