[Bug c++/57555] Warning on negation of constexpr uint8_t being assigned to uint8_t

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57555

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The standard says that ~foo has type int and value -256, so assigning it to
uint8_t changes the value, so the warning is correct.

The warning is only given when foo is constant because otherwise the value of
~foo is not a compile-time constant.