[Bug c++/95349] Using std::launder(p) produces unexpected behavior where (p) produces expected behavior

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95349

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Using 

  auto t = new(p) std::uint64_t;
  std::memcpy(t, std::launder(storage), sizeof(storage));
  return t;

also prevents GCC from propagating the dynamic type of p to t.