When in the parent class destructor, the v-table will point toward the parent's v-table not the child's (try it out), so I'm not sure how you'd call a virtual method accessing a child member.
Would it? Or is it undefined? No C++ runtime I know of will generate a new, different vtbl just to switch it out when invoking the non-owning base class destructor on an object. Nor am I familiar with any part of the C++ stnadrd that mandates this behaviour, or even mandates vtbls.
It doesn't create a new vtbl, when invoking the base object destructor it just repoints the current vtable ptr to the base object vtable as first thing:
https://godbolt.org/z/MKx6oTE63
I can't recite chapter and verse, but I'm pretty sure that's mandated by the standard and it mirrors the behaviour in the constructor.
