[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 #2 from Paolo Carlini <paolo.carlini at oracle dot com> ---
Thanks Jakub for looking into this. For sure, the whole fold and convert
machinery should not be necessary for something this simple, but, to be honest,
isn't immediately obvious to me why it does the wrong thing in this case.