https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86355
--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-11 branch has been updated by Jason Merrill <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:542d90bfd802274f38637aaaffc2dd1de62c9ec6 commit r11-8714-g542d90bfd802274f38637aaaffc2dd1de62c9ec6 Author: Jason Merrill <ja...@redhat.com> Date: Wed May 26 17:38:42 2021 -0400 c++: argument pack with expansion [PR86355] This testcase revealed that we were using PACK_EXPANSION_EXTRA_ARGS a lot more than necessary; use_pack_expansion_extra_args_p meant to use it in the case of corresponding arguments in different argument packs differing in whether they are pack expansions, but it was mistakenly also returning true for the case of a single argument pack containing both expansion and non-expansion elements. Surprisingly, just disabling that didn't lead to any regressions in the testsuite; it seems other changes have prevented us getting to this point for code that used to exercise it. So this patch limits the check to arguments in the same position in the packs, and asserts that we never actually see a mismatch. PR c++/86355 gcc/cp/ChangeLog: * pt.c (use_pack_expansion_extra_args_p): Don't compare args from the same argument pack. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/alias-decl-variadic2.C: New test.
