[Bug c++/72457] [6/7 Regression] ICE: Segmentation fault

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72457

--- Comment #7 from Jason Merrill <jason at gcc dot gnu.org> ---
Reduced:

template <typename Element> struct box {
  Element value;
  constexpr box() : value{} {}
};
struct B: box<int> { };
template box<B>::box();