https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66216
--- Comment #2 from James Almer <jamrial at gmail dot com> --- (In reply to Jonathan Wakely from comment #1) > And now it gives an ICE on trunk, so it's regressed from rejects-valid to > ice-on-valid-code: > > a.cc:1:7: internal compiler error: canonical types differ for identical > types const CMymy and const CMymy > class CMymy This may be a duplicate of pr65936 then, or related.