[Bug c++/118661] [12/13/14/15 regression] Reading volatile qualified std::nullptr_t should be valid in a constant expression

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

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

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2025-01-26
      Known to fail|                            |9.1.0
                 CC|                            |pinskia at gcc dot gnu.org

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed. Note I think there is 2 different changes which caused this.

That is a change in 8 caused use to reject:
```
typedef decltype(nullptr) tt;
constexpr volatile tt n{};
constexpr tt m=n;
```

But it was not until GCC 9 we (correctly) rejected:
```
constexpr volatile int n1{};
constexpr short m1=n1;
```