[Bug c++/91780] Discrepancy between gcc 7.4, through 9.2, compared to clang.

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91780

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #4)
> Fixed by r11-1571 and r10-8343, although I'm not sure how that affected it.

I suspect it is the tsubst_pack_expansion change.