https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93713
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Started with r10-3735-gcb57504a550158913258e5be8ddb991376475efb
commit cb57504a550158913258e5be8ddb991376475efb
Author: Jason Merrill <ja...@gcc.gnu.org>
Date: Wed Oct 9 13:20:32 2019 -0400
Update the concepts implementation to conform to C++20.
