51     std::same_as<Result> decltype(auto) v = std::views::join(inners);  in test()
60     std::same_as<Result> decltype(auto) v = std::views::join(MoveOnlyOuter{inners});  in test()
64     static_assert(std::invocable<decltype(std::views::join), MoveOnlyOuter>);  in test()
65     static_assert(!std::invocable<decltype(std::views::join), MoveOnlyOuter&>);  in test()
71     auto jv = std::views::join(nested);  in test()
74     auto jv2 = std::views::join(jv);  in test()
85     std::same_as<Result> decltype(auto) v = inners | std::views::join;  in test()
88     static_assert(CanBePiped<decltype((inners)), decltype((std::views::join))>);  in test()
95     std::same_as<Result> decltype(auto) v = MoveOnlyOuter{inners} | std::views::join;  in test()
99     static_assert(CanBePiped<MoveOnlyOuter, decltype((std::views::join))>);  in test()
100     static_assert(!CanBePiped<MoveOnlyOuter&, decltype((std::views::join))>);  in test()
106     auto jv = nested | std::views::join | std::views::join;  in test()
110     static_assert(CanBePiped<decltype((nested)), decltype((std::views::join))>);  in test()
115     auto join_twice = std::views::join | std::views::join;  in test()
124     static_assert(!CanBePiped<int, decltype((std::views::join))>);  in test()
125     static_assert(!CanBePiped<Foo, decltype((std::views::join))>);  in test()
126     static_assert(!CanBePiped<int(&)[2], decltype((std::views::join))>);  in test()
127     static_assert(CanBePiped<int(&)[2][2], decltype((std::views::join))>);  in test()