[Bug c++/99535] g++ rejects valid code in constexpr copy ctor and volatile submember

[Darrell.Wright at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99535

--- Comment #1 from Darrell Wright <Darrell.Wright at gmail dot com> ---
I was wrong, http://eel.is/c++draft/expr.const#5.8