#include <string>
#include <cassert>
#include <type_traits>
template <class T>
void
test()
{
typedef std::hash<T> H;
static_assert((std::is_base_of<std::unary_function<T, std::size_t>,
H>::value), "");
H h;
std::string g1 = "1234567890";
std::string g2 = "1234567891";
T s1(g1.begin(), g1.end());
T s2(g2.begin(), g2.end());
assert(h(s1) != h(s2));
}
int main()
{
test<std::string>();
#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
test<std::u16string>();
test<std::u32string>();
#endif // _LIBCPP_HAS_NO_UNICODE_CHARS
test<std::wstring>();
}