Fix std::result_of removed in C++20 (#551)

ReactiveX · Aug 26, 2021 · 76de2c1 · 76de2c1
1 parent 9002d9b
commit 76de2c1
Showing 1 changed file with 13 additions and 2 deletions.
diff --git a/Rx/v2/src/rxcpp/rx-util.hpp b/Rx/v2/src/rxcpp/rx-util.hpp
@@ -46,7 +46,18 @@ namespace util {
 
 template<class T> using value_type_t = typename std::decay<T>::type::value_type;
 template<class T> using decay_t = typename std::decay<T>::type;
-template<class... TN> using result_of_t = typename std::result_of<TN...>::type;
+#ifdef __cpp_lib_is_invocable
+template <class> struct result_of;
+
+template <class F, class... TN>
+struct result_of<F(TN...)>
+{
+    using type = std::invoke_result_t<F, TN...>;
+};
+#else
+template<class... TN> using result_of = std::result_of<TN...>;
+#endif
+template<class... TN> using result_of_t = typename result_of<TN...>::type;
 
 template<class T, std::size_t size>
 std::vector<T> to_vector(const T (&arr) [size]) {
@@ -1013,7 +1024,7 @@ struct is_hashable<T,
     typename rxu::types_checked_from<
         typename filtered_hash<T>::result_type,
         typename filtered_hash<T>::argument_type,
-        typename std::result_of<filtered_hash<T>(T)>::type>::type>
+        typename rxu::result_of<filtered_hash<T>(T)>::type>::type>
     : std::true_type {};
 
 }