Exclusive references make Rust, yet they cannot be built within Rust: the core act of reborrowing, that is giving temporary exclusive access and reclaiming exclusivity afterwards, is a feature implemented outside of the language. For custom user types or even reference wrappers like Option<&mut T> the best one can do is use explicit methods like as_deref_mut or rb_mut. The Reborrow traits project goal aims to fix this gap and make exclusive references buildable within the language. Come hear the how and why, why-nots, and what is to come!