[Bug c++/90548] [9/10 Regression] ICE in tsubst_copy_and_build, at cp/pt.c:18877

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90548

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
We ended up with an empty call_args vec because the pack expanded here:
18842                 /* Expand the pack expansion and push each entry onto
18843                    CALL_ARGS.  */
18844                 arg = tsubst_pack_expansion (arg, args, complain,
in_decl);
expanded to an empty vector.  So nothing got pushed onto call_args.