[Bug c++/102163] [10/11/12 Regression] std::variant rejects valid constant expression

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102163

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note this works:

struct O {
  constexpr O() {}
};

union _Variadic_union
{
  constexpr _Variadic_union() : _M_rest() { }
  O _M_rest;
};

constexpr _Variadic_union w;
----- CUT ---
But this fails:
struct O {
  constexpr O() {}
};

union _Variadic_union
{
  constexpr _Variadic_union() : _M_rest{} { }
  O _M_rest;
};

constexpr _Variadic_union w;