122 constexpr bool can_hash(int) {  in can_hash()  function
125 template <class> constexpr bool can_hash(long) { return false; }  in can_hash()  function
126 template <class T> constexpr bool can_hash() { return can_hash<T>(0); }  in can_hash()  function
149   static_assert(can_hash<Hash(Key&)>(), "");  in test_hash_enabled()
150   static_assert(can_hash<Hash(Key const&)>(), "");  in test_hash_enabled()
151   static_assert(can_hash<Hash(Key&&)>(), "");  in test_hash_enabled()
152   static_assert(can_hash<Hash const&(Key&)>(), "");  in test_hash_enabled()
153   static_assert(can_hash<Hash const&(Key const&)>(), "");  in test_hash_enabled()
154   static_assert(can_hash<Hash const&(Key&&)>(), "");  in test_hash_enabled()
156   static_assert(can_hash<Hash(ConvertibleToSimple<Key>&)>(), "");  in test_hash_enabled()
157   static_assert(can_hash<Hash(ConvertibleToSimple<Key> const&)>(), "");  in test_hash_enabled()
158   static_assert(can_hash<Hash(ConvertibleToSimple<Key>&&)>(), "");  in test_hash_enabled()
160   static_assert(can_hash<Hash(ConvertibleTo<Key>&)>(), "");  in test_hash_enabled()
161   static_assert(can_hash<Hash(ConvertibleTo<Key> const&)>(), "");  in test_hash_enabled()
162   static_assert(can_hash<Hash(ConvertibleTo<Key> &&)>(), "");  in test_hash_enabled()
163   static_assert(can_hash<Hash(ConvertibleTo<Key> const&&)>(), "");  in test_hash_enabled()
188   static_assert(!can_hash<Hash(Key&)>(), "");  in test_hash_disabled()
189   static_assert(!can_hash<Hash(Key const&)>(), "");  in test_hash_disabled()
190   static_assert(!can_hash<Hash(Key&&)>(), "");  in test_hash_disabled()
191   static_assert(!can_hash<Hash const&(Key&)>(), "");  in test_hash_disabled()
192   static_assert(!can_hash<Hash const&(Key const&)>(), "");  in test_hash_disabled()
193   static_assert(!can_hash<Hash const&(Key&&)>(), "");  in test_hash_disabled()
195   static_assert(!can_hash<Hash(ConvertibleToSimple<Key>&)>(), "");  in test_hash_disabled()
196   static_assert(!can_hash<Hash(ConvertibleToSimple<Key> const&)>(), "");  in test_hash_disabled()
197   static_assert(!can_hash<Hash(ConvertibleToSimple<Key>&&)>(), "");  in test_hash_disabled()
199   static_assert(!can_hash<Hash(ConvertibleTo<Key>&)>(), "");  in test_hash_disabled()
200   static_assert(!can_hash<Hash(ConvertibleTo<Key> const&)>(), "");  in test_hash_disabled()
201   static_assert(!can_hash<Hash(ConvertibleTo<Key> &&)>(), "");  in test_hash_disabled()
202   static_assert(!can_hash<Hash(ConvertibleTo<Key> const&&)>(), "");  in test_hash_disabled()