https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116223
--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Jason Merrill <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:4add6cd341a779e980e41ed6fb49175fca37496e commit r15-2760-g4add6cd341a779e980e41ed6fb49175fca37496e Author: Jason Merrill <ja...@redhat.com> Date: Mon Aug 5 11:21:05 2024 -0400 c++: alias and non-type template parm [PR116223] My r14-8291 for PR112632 introduced IMPLICIT_CONV_EXPR_FORCED to express conversions to the type of an alias template parameter. In this example, that broke deduction of X in the call to foo, so let's teach deduction to look through it. PR c++/116223 PR c++/112632 gcc/cp/ChangeLog: * pt.cc (deducible_expression): Also look through IMPLICIT_CONV_EXPR_FORCED. (unify): Likewise. gcc/testsuite/ChangeLog: * g++.dg/cpp1z/nontype-auto25.C: New test.