[Bug c++/63515] unused templated member can be instatiated

[luka.rahne at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63515

--- Comment #2 from Luka Rahne <luka.rahne at gmail dot com> ---
This bug boils to to point where in member function

    template <typename... Rem>
    CurriedImpl<Depth-sizeof...(Rem),F> 
    //sizeof...(Rem) depends here on size of arguments of std::function
    operator()(Rem ... a_rem) 
    {
    }

deduced number of arguments depends on number of arguments in F