https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72842
--- Comment #5 from Daniel Krügler <daniel.kruegler at googlemail dot com> --- (In reply to Barry Revzin from comment #4) > I'll just email. Instantiating foo<void> creates a function template with a > non-type template parameter of type void. That's not an allowed type of a > non-type template parameter, so I think it should be ill-formed. It truely is ill-formed, but the question is whether an implementation is required to diagnose it. For the non-depending case the diagnostics is a hard requirement. But for the dependent case we have [temp.res] p8: "The program is ill-formed, no diagnostic required, if: [..] — every valid specialization of a variadic template requires an empty template parameter pack, or [..]" My argument is that this is the case we are entering here: Ill-formed, but no diagnostics required.
