Without any context it’s impossible to tell if code needs to be that obtuse or if uou somehow built your way into a setup that you could’ve avoided. ;P
GP is suggesting that one typically finds oneself in such a situation with idiomatic code. Even if it can be avoided with some effort, it will all too easily not be avoided.
self.last.as_ref().unwrap().borrow().next.as_ref().unwrap().clone()
I know it can be improved but that's what I think of