[Bug c++/118661] [12 regression] Reading volatile qualified std::nullptr_t should be valid in a constant expression

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118661

--- Comment #14 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Halalaluyafail3 from comment #0)
> > - an lvalue-to-rvalue conversion (7.3.2) unless it is applied to
> >   - a glvalue of type cv std::nullptr_t,

https://cplusplus.github.io/CWG/issues/2907.html added the above part.