[Bug c++/87571] [8/9 Regression] ICE in friend_accessible_p, accessing protected member of template friend inside template class

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87571

--- Comment #4 from Paolo Carlini <paolo.carlini at oracle dot com> ---
This is fixed in trunk. I'm adding the testcase and removing the regression
marker.