https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88395
--- Comment #14 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-9 branch has been updated by Jason Merrill <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:e50627ff8cd54c3983614b34727323b333b9374d commit r9-8351-ge50627ff8cd54c3983614b34727323b333b9374d Author: Jason Merrill <ja...@redhat.com> Date: Thu Mar 5 13:45:38 2020 -0500 c++: Avoid ICE on infinite recursion with concepts. This was simple enough to backport even though it's concepts. gcc/cp/ChangeLog 2020-03-05 Jason Merrill <ja...@redhat.com> PR c++/88395 PR c++/93551 * constraint.cc (constraints_satisfied_p): Use push_tinst_level.