template<typename regular_type> class Policy {};
template <typename regular_type, template<typename> class OriginalPolicy>
class ChangedPolicy_impl {};
template <template<typename> class OriginalPolicy > class ChangedPolicy {
public:
template<typename regular_type> class Type : public
ChangedPolicy_impl<regular_type,OriginalPolicy> { };
};
template <typename regular_type, template<typename> class Policy1,
template<typename> class Policy2
= ChangedPolicy<Policy1>::template Type>
class Host : public Policy1<regular_type>, public Policy2<regular_type> { };
int main()
{
Host<void, Policy> h;
return 0;
}