27         optional<T> opt;  in main()  local
28         assert(std::hash<optional<T>>{}(opt) == 0);  in main()
29         opt = 2;  in main()
30         assert(std::hash<optional<T>>{}(opt) == std::hash<T>{}(*opt));  in main()
34         optional<T> opt;  in main()  local
35         assert(std::hash<optional<T>>{}(opt) == 0);  in main()
36         opt = std::string("123");  in main()
37         assert(std::hash<optional<T>>{}(opt) == std::hash<T>{}(*opt));  in main()
41         optional<T> opt;  in main()  local
42         assert(std::hash<optional<T>>{}(opt) == 0);  in main()
43         opt = std::unique_ptr<int>(new int(3));  in main()
44         assert(std::hash<optional<T>>{}(opt) == std::hash<T>{}(*opt));  in main()