[Bug c++/60760] arithmetic on null pointers should not be allowed in constant expressions

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60760

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Yes, we rely on that in initializer_list<>::end(), and clang rejects that.

I discussed that case with Jason and we think [expr.add] could be clarified -
do you have an existing issue number related to that?