| #if defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) < 407) |
| # define OLD_GNU |
| #endif |
| |
| #ifdef OLD_GNU |
| template <int... Is> |
| struct Interface; |
| #endif |
| |
| template <int I, int... Is> |
| struct Interface |
| #ifdef OLD_GNU |
| <I, Is...> |
| #endif |
| { |
| static int accumulate() { return I + Interface<Is...>::accumulate(); } |
| }; |
| |
| template <int I> |
| struct Interface<I> |
| { |
| static int accumulate() { return I; } |
| }; |
| |
| // Note: split this into a separate test if a |
| // cxx_variadic_template_template_parameters feature is added. |
| |
| template <typename T> |
| struct eval |
| { |
| enum |
| { |
| Matched = 0 |
| }; |
| }; |
| |
| template <template <typename...> class T, typename... U> |
| struct eval<T<U...>> |
| { |
| enum |
| { |
| Matched = 1 |
| }; |
| }; |
| |
| template <typename...> |
| struct A |
| { |
| }; |
| template <typename T> |
| struct B |
| { |
| }; |
| template <typename T, typename U> |
| struct C |
| { |
| }; |
| template <typename T, typename U, typename...> |
| struct D |
| { |
| }; |
| |
| // Note: This test assumes that a compiler supporting this feature |
| // supports static_assert. Add a workaround if that does not hold. |
| static_assert(eval<A<>>::Matched, "A Matches"); |
| static_assert(eval<A<int>>::Matched, "A Matches"); |
| static_assert(eval<A<int, char>>::Matched, "A Matches"); |
| static_assert(eval<B<int>>::Matched, "B Matches"); |
| static_assert(eval<C<int, char>>::Matched, "C Matches"); |
| static_assert(eval<D<int, char>>::Matched, "D Matches"); |
| static_assert(eval<D<int, char, bool>>::Matched, "D Matches"); |
| static_assert(eval<D<int, char, bool, double>>::Matched, "D Matches"); |