https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84126
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Started with r257018: commit 2100de5308865b06be2b235ed159b5af9a9a67a5 Author: jason <jason@138bc75d-0d04-0410-961f-82ee72b054a4> Date: Wed Jan 24 15:20:53 2018 +0000 PR c++/82249 - wrong mismatched pack length error. * pt.c (extract_fnparm_pack, tsubst_pack_expansion): Handle unsubstituted function parameter pack.