37     using std::optional;  in main()
39         std::hash<optional<double>>{}(optional<double>{});  in main()
43         optional<B> opt;  in main()
44         ASSERT_NOT_NOEXCEPT(std::hash<optional<B>>()(opt));  in main()
45         ASSERT_NOT_NOEXCEPT(std::hash<optional<const B>>()(opt));  in main()
50         optional<T> opt;  in main()
51         assert(std::hash<optional<T>>{}(opt) == nullopt_hash);  in main()
53         assert(std::hash<optional<T>>{}(opt) == std::hash<T>{}(*opt));  in main()
57         optional<T> opt;  in main()
58         assert(std::hash<optional<T>>{}(opt) == nullopt_hash);  in main()
60         assert(std::hash<optional<T>>{}(opt) == std::hash<T>{}(*opt));  in main()
64         optional<T> opt;  in main()
65         assert(std::hash<optional<T>>{}(opt) == nullopt_hash);  in main()
67         assert(std::hash<optional<T>>{}(opt) == std::hash<T>{}(*opt));  in main()
70       test_hash_enabled_for_type<std::optional<int> >();  in main()
71       test_hash_enabled_for_type<std::optional<int*> >();  in main()
72       test_hash_enabled_for_type<std::optional<const int> >();  in main()
73       test_hash_enabled_for_type<std::optional<int* const> >();  in main()
75       test_hash_disabled_for_type<std::optional<A>>();  in main()
76       test_hash_disabled_for_type<std::optional<const A>>();  in main()
78       test_hash_enabled_for_type<std::optional<B>>();  in main()
79       test_hash_enabled_for_type<std::optional<const B>>();  in main()