fixed the return type of getting an element from an rvalue product_type (#107)

Author: dietmarkuehl

include/beman/execution26/detail/product_type.hpp

@@ -29,7 +29,7 @@ struct product_type_base<::std::index_sequence<I...>, T...>
         return self.value;
     }
     template <::std::size_t J, typename S>
-    static auto element_get(::beman::execution26::detail::product_type_element<J, S>&& self) noexcept -> S {
+    static auto element_get(::beman::execution26::detail::product_type_element<J, S>&& self) noexcept -> S&& {
         return ::std::move(self.value);
     }
     template <::std::size_t J, typename S>

tests/beman/execution26/exec-snd-expos.test.cpp

@@ -1253,11 +1253,11 @@ auto test_write_env() -> void {
 template <typename... T>
 struct child_sender : test_detail::product_type<T...> {};
 auto test_child_type() -> void {
-    static_assert(std::same_as<int, test_detail::child_type<child_sender<bool, char, int, double>>>);
-    static_assert(std::same_as<int&, test_detail::child_type<child_sender<bool, char, int, double>>&>);
-    static_assert(std::same_as<const int&, const test_detail::child_type<child_sender<bool, char, int, double>>&>);
-    static_assert(std::same_as<int, test_detail::child_type<child_sender<bool, char, int, double>, 0>>);
-    static_assert(std::same_as<double, test_detail::child_type<child_sender<bool, char, int, double>, 1>>);
+    static_assert(std::same_as<int&&, test_detail::child_type<child_sender<bool, char, int, double>>>);
+    static_assert(std::same_as<int&, test_detail::child_type<child_sender<bool, char, int, double>&>>);
+    static_assert(std::same_as<const int&, test_detail::child_type<const child_sender<bool, char, int, double>&>>);
+    static_assert(std::same_as<int&&, test_detail::child_type<child_sender<bool, char, int, double>, 0>>);
+    static_assert(std::same_as<double&&, test_detail::child_type<child_sender<bool, char, int, double>, 1>>);
 }
 } // namespace