88     static_assert(std::is_same<decltype(1_d), day>{}, "");  in main()
90     static_assert(1_d == day{1}, "");  in main()
91     static_assert(2_d == day{2}, "");  in main()
93     static_assert(  1_d == 1_d, "");  in main()
94     static_assert(!(1_d == 2_d), "");  in main()
95     static_assert(!(2_d == 1_d), "");  in main()
97     static_assert(!(1_d != 1_d), "");  in main()
98     static_assert(  1_d != 2_d, "");  in main()
99     static_assert(  2_d != 1_d, "");  in main()
101     static_assert(!(1_d <  1_d), "");  in main()
102     static_assert(  1_d <  2_d, "");  in main()
103     static_assert(!(2_d <  1_d), "");  in main()
105     static_assert(  1_d <= 1_d, "");  in main()
106     static_assert(  1_d <= 2_d, "");  in main()
107     static_assert(!(2_d <= 1_d), "");  in main()
109     static_assert(!(1_d >  1_d), "");  in main()
110     static_assert(!(1_d >  2_d), "");  in main()
111     static_assert(  2_d >  1_d, "");  in main()
113     static_assert(  1_d >= 1_d, "");  in main()
114     static_assert(!(1_d >= 2_d), "");  in main()
115     static_assert(  2_d >= 1_d, "");  in main()
117     static_assert(3_d + days{7} == 10_d, "");  in main()
118     static_assert(days{7} + 3_d == 10_d, "");  in main()
119     static_assert(3_d + weeks{1} == 10_d, "");  in main()
120     static_assert(weeks{1} + 3_d == 10_d, "");  in main()
122     static_assert(7_d - days{3} == 4_d, "");  in main()
123     static_assert(3_d - 7_d == days{-4}, "");  in main()
124     static_assert(25_d - 11_d == weeks{2}, "");  in main()
126     auto d = 1_d;  in main()
127     assert(++d == 2_d);  in main()
128     assert(d++ == 2_d);  in main()
129     assert(d == 3_d);  in main()
130     assert(d-- == 3_d);  in main()
131     assert(d == 2_d);  in main()
132     assert(--d == 1_d);  in main()
133     assert((d += days{2}) == 3_d);  in main()
134     assert((d -= days{2}) == 1_d);  in main()