[Bug c++/91525] ICE (Segmentation Fault) on a bool conversion operator with concepts

[gcc-bugs at marehr dot dialup.fu-berlin.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91525

--- Comment #2 from gcc-bugs at marehr dot dialup.fu-berlin.de ---
This still fails and furthermore fails in `-std=c++2a` mode as well.