Idea / Pre-RFC: Null-free pointer and Zeroable reference

H4n_uL:

Once you need lifetime tracking, borrow semantics, and field projection on a pointer type, it becomes difficult to express that purely as a library type without compiler support.

We already have smart pointers that provide lifetime tracking and borrow semantics. Field projection is being worked on. Once that's ready, I expect that's enough compiler support to do the rest as a library type.