The RefCell chapter gives the reader an impression that RefCell is no different from Box other than the additional support of runtime mutability check. However there's another big difference: Box manages object on the heap while RefCell is just a stack variable wrapper. I think this needs to be clearly stated when introducing RefCell to the reader, otherwise it can cause confusions (see this discussion in the forum).
The RefCell chapter gives the reader an impression that RefCell is no different from Box other than the additional support of runtime mutability check. However there's another big difference: Box manages object on the heap while RefCell is just a stack variable wrapper. I think this needs to be clearly stated when introducing RefCell to the reader, otherwise it can cause confusions (see this discussion in the forum).