[Bug c++/85553] [8/9 Regression] cannot list-initialize a variable of type std::nullptr_t

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85553

--- Comment #4 from Paolo Carlini <paolo.carlini at oracle dot com> ---
I see. Then, my humble opinion (we got Jason in CC, anyway) is that if we are
still hoping to have this fixed in 8.1.0 we should just go ahead with something
rather straightforward like your tweak, otherwise we should probably
investigate the constexpr.c behavior a little more, because I don't really see
why going from integer_zero_node to NULLPTR_TYPE_P is "better" than going from
nullptr_node to NULLPTR_TYPE_P, if you see what I mean.