21 using std::optional;
26     const optional<T> rhs(std::forward<InitArgs>(args)...);  in test()
28     optional<T> lhs = rhs;  in test()
38     const optional<T> rhs(std::forward<InitArgs>(args)...);  in constexpr_test()
39     optional<T> lhs = rhs;  in constexpr_test()
53     const optional<Z> rhs(z);  in test_throwing_ctor()
56         optional<Z> lhs(rhs);  in test_throwing_ctor()
69     const optional<T> rhs(std::forward<InitArgs>(args)...);  in test_ref()
71     optional<T> lhs = rhs;  in test_ref()
110         static_assert(!std::is_copy_constructible<std::optional<T&&>>::value, "");  in test_reference_extension()
111         static_assert(!std::is_copy_constructible<std::optional<T const&&>>::value, "");  in test_reference_extension()
124         const optional<const int> o(42);  in main()
125         optional<const int> o2(o);  in main()
131         const optional<T> rhs;  in main()
133         const optional<T> lhs(rhs);  in main()
141         const optional<T> rhs(42);  in main()
145         const optional<T> lhs(rhs);  in main()
168         constexpr std::optional<int> o1{4};  in main()
169         constexpr std::optional<int> o2 = o1;  in main()