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// PR c++/93377
// { dg-do compile { target c++20 } }
struct empty
{};
template <typename c>
c value;
template <typename c>
auto func(value<c>);
template <typename, typename...>
struct alignment_algorithm;
template <typename... args_t>
struct select
{
template <typename algorithm_t, typename... _args_t>
decltype(algorithm_t()(func<_args_t>...)) choose();
template <typename...>
static empty choose();
using type = decltype(choose<alignment_algorithm<int>, args_t...>());
};
template <typename, typename... args_t>
struct select_algorithm : select<args_t...>
{};
template <typename, typename = void> struct maybe_value { int value; };
template <typename cn>
struct maybe_value<cn, typename cn::sfinae>;
struct function
{
template <typename algorithm_t,
typename = decltype(
maybe_value<select_algorithm<algorithm_t, int>>::value)>
function(algorithm_t);
};
template <typename>
struct alignment_configuration_traits
{
static constexpr bool is_vectorised = 0;
};
template <typename config_t, typename...>
struct alignment_algorithm
{
using traits_t = alignment_configuration_traits<config_t>;
template <typename indexed_sequence_pairs_t>
void operator()(indexed_sequence_pairs_t) requires traits_t::is_vectorised;
};
int main()
{
function{alignment_algorithm<int>{}};
}
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