1 // { dg-do compile { target c++17 } } 2 3 template <class T> 4 struct A 5 { 6 template <class U> 7 static constexpr bool B = U(); 8 9 template <class U, bool V = B<U>> 10 A(T, U); 11 }; 12 13 A a (1,2); 14