[Bug c++/67047] GCC accepts ill-formed program with enumerator not representable in uintmax_t

[anders.granlund.0 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67047

--- Comment #3 from Anders Granlund <anders.granlund.0 at gmail dot com> ---
It seems like the increment of the enumerator x triggered the use of the
following compiler extension:

https://gcc.gnu.org/onlinedocs/gcc/_005f_005fint128.html

This without any error messages. That is not ok! Remember that we used
-pedantic-errors.