> I'm pretty sure the question was why a normal reference is bad. Oh, completely missed that interpretation. I think in that case it comes down to references b

> I'm pretty sure the question was why a normal reference is bad. Oh, completely missed that interpretation. I think in that case it comes down to references being incompatible with the desired semantics for an intrusive list - & doesn't work if you want to modify what you're pointing to, and &mut doesn't work since you may want multiple things to be able to point to and modify whatever you're pointing to.