// { dg-do compile { target c++11 } }

#define ONE
#define TWO
#define THREE

struct Something {};
Something ___;

template <class F>
struct Trial
{
 F f;
public:
 Trial() : f() {}
 Trial( const F& ff ) : f(ff) { }
 template <typename... Args>
 struct Sig { typedef int ResultType; };

 template <typename... Args>
 struct Sig<Something,Args...> { typedef int ResultType;  };

#ifdef ONE

template <typename... Args>
typename Sig<Something,Args...>::ResultType operator()(const Something& s, const Args&... args) const
{
 return f(args...);
}
#endif
#ifdef TWO
template <typename... Args>
typename Sig<Args...>::ResultType operator()(const Args&... args) const
{
 return f(args...);
}
#endif
};

struct Internal
{

template <typename... Args>
struct Sig { typedef int ResultType; };

template <typename... Args>
struct Sig<Something,Args...> { typedef int ResultType;  };

template <typename... Args>
int operator()(const Args&... args) const
{
 int n = sizeof...(Args);
 return n;
}

 static Trial<Internal>& full() { static Trial<Internal> f; return f; }
};

static Trial<Internal>& internal = Internal::full();

int main()
{
 int n = 0;
#ifdef ONE
 n = internal(___,1,2);
#endif
#ifdef THREE
 n = internal(___,1,2,3);
 n = internal(___,1,2,3,4);
#endif
 return 0;
}