[Bug libstdc++/64367] [5 Regression] g++-v5/stdexcept:52:28: error: invalid use of non-static data member '_M_p'

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64367

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I don't know why clang complains, it accepts this, which shouldn't be any
different:

  char _M_bytes[sizeof(decltype(_M_p))];