https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67332
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- clang rejects it: <source>:9:5: error: no matching function for call to 'foo' foo (Typelist<double>(), Typelist<int>(), 2.5, 1); ^~~ <source>:5:6: note: candidate template ignored: deduced packs of different lengths for parameter 'InvokableArgs' (<double> vs. <>) void foo (Typelist<InvokableArgs...>, Typelist<Rest...>, InvokableArgs&&..., Rest&&...) { } ^