[Bug c++/125490] GCC accepts an invalid concept that compares sizeof(T) with nullptr

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125490

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ppalka at gcc dot gnu.org
   Last reconfirmed|                            |2026-05-29
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW

--- Comment #2 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Since the operands of == aren't type dependent it makes sense to reject it at
parse time.

Interestingly we do already reject

template<class T>
concept C1 = true && sizeof(T) == nullptr;