[Bug libstdc++/114940] std::generator relies on an optional overload of operator delete

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114940

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2024-05-03
                 CC|                            |arsen at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
It's not optional, it's a required feature in C++14 and later. Failing to
provide it is non-conforming, although GCC can be requested to be
non-conforming the same way with -fno-sized-deallocation. Using that, the same
error happens with GCC.

We should either disable __cpp_lib_generator when __cpp_sized_deallocation is
not defined, or change <generator> to not depend on it unconditionally.