https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105491
--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> --- // PR c++/105491 struct V { virtual int foo(); }; struct S : V { constexpr S(int) : b() { } bool b; }; struct W { constexpr W() : s({}) {} union { S s; }; }; constexpr W w;