1 // PR c++/48452 2 // { dg-do compile { target c++11 } } 3 namespace std { 4 template <class T> T&& declval(); 5 } 6 7 template<class T, class... Args> 8 decltype(T(std::declval<Args>()...), char()) f(int); 9 10 template<class, class...> 11 char (&f(...))[2]; 12 13 struct A { virtual ~A() = 0; }; 14 struct B {}; 15 16 static_assert(sizeof(f<A, int, int>(0)) != 1, "Error"); // a 17 static_assert(sizeof(f<B, void, int>(0)) != 1, "Error"); // b 18 static_assert(sizeof(f<void, int, int>(0)) != 1, "Error"); // c 19