https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66834
--- Comment #10 from Jason Merrill <jason at gcc dot gnu.org> --- (In reply to Jason Merrill from comment #9) So it seems that applying the DR 1430 tentative resolution to concepts severely limits the usability of variadic concepts, and we should reconsider that, so that instead we delay normalization of template-ids with variadic arguments until instantiation time. The restriction on expansion arguments to non-expansion parameters initially applied to all variadic templates until N2555, which Eric was also involved with... I guess I'll revert my change for the moment.
