https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66477
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jason Merrill <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:87fbd5347b33883006dc77e779b9edc590fcd2f0 commit r10-6417-g87fbd5347b33883006dc77e779b9edc590fcd2f0 Author: Jason Merrill <ja...@redhat.com> Date: Mon Feb 3 16:03:45 2020 -0500 c++: Fix constexpr vs. reference parameter. [expr.const] specifically rules out mentioning a reference even if its address is never used, because it implies indirection that is similarly non-constant for a pointer variable. PR c++/66477 * constexpr.c (cxx_eval_constant_expression) [PARM_DECL]: Don't defer loading the value of a reference.