// PR c++/78489 // { dg-do compile { target c++11 } } template <bool P, class T = void> struct enable_if { using type = T; }; template <class T> struct enable_if<false, T> {}; template <class Dummy> struct use_type { using type = int; }; template <bool Pred> struct get_type { static_assert(Pred, ""); using type = int; }; template <bool Val, class = typename enable_if<Val>::type, // Evaluation/Substitution should end here class ValT = typename get_type<Val>::type, // This should not be instantiated typename use_type<ValT>::type = 0 // This NTTP causes ValT to be required > constexpr bool test(int) { return false; } template <bool> constexpr bool test(long) { return true; } static_assert(test<false>(0), ""); // should call test(long)