https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97710
--- Comment #6 from Mick P. <mick.pearson at wildblue dot net> --- Desired scenario: https://godbolt.org/z/zKnh1s template<class A, char A::*> struct T{}; struct A{}; struct B:A{ int x; }; struct C:A{ T<A,(char A::*)&B::x> y; }; Changing x to char yields the other diagnostic. PtoM types are fungible, I don't know why casting should restrict them to concrete types this way, even if the standard says so that's a straight-jacket just for strong type-safeness sake.
