GHSA-RJHF-4MH8-9XJQ Zerocopy: Some Ref methods are unsound with some type parameters

The Ref methods intoref, intomut, intoslice, and intoslicemut are unsound and may allow safe code to exhibit undefined behavior when used with Ref where B is cell::Ref or cell::RefMut. Note that these methods remain sound when used with B types other than cell::Ref or cell::RefMut. See...