#include <string>
#include <type_traits>
#include <cstdint>
int main()
{
#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
static_assert((std::is_same<std::char_traits<char32_t>::char_type, char32_t>::value), "");
static_assert((std::is_same<std::char_traits<char32_t>::int_type, std::uint_least32_t>::value), "");
static_assert((std::is_same<std::char_traits<char32_t>::off_type, std::streamoff>::value), "");
static_assert((std::is_same<std::char_traits<char32_t>::pos_type, std::u32streampos>::value), "");
static_assert((std::is_same<std::char_traits<char32_t>::state_type, std::mbstate_t>::value), "");
#endif // _LIBCPP_HAS_NO_UNICODE_CHARS
}