From 4d87e19b0162197e9bb8f3476d92fb876632ec83 Mon Sep 17 00:00:00 2001
From: Charles Milette <charles.milette@gmail.com>
Date: Sun, 29 Mar 2020 19:47:18 -0400
Subject: [PATCH] Fix usage of result_of under C++20

---
 googlemock/include/gmock/gmock-actions.h               |  2 +-
 .../include/gmock/internal/gmock-internal-utils.h      | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/googlemock/include/gmock/gmock-actions.h b/googlemock/include/gmock/gmock-actions.h
index b4127e93..4f7d99f7 100644
--- a/googlemock/include/gmock/gmock-actions.h
+++ b/googlemock/include/gmock/gmock-actions.h
@@ -970,7 +970,7 @@ struct InvokeMethodWithoutArgsAction {
   Class* const obj_ptr;
   const MethodPtr method_ptr;
 
-  using ReturnType = typename std::result_of<MethodPtr(Class*)>::type;
+  using ReturnType = typename InvokeResult<MethodPtr, Class*>::type;
 
   template <typename... Args>
   ReturnType operator()(const Args&...) const {
diff --git a/googlemock/include/gmock/internal/gmock-internal-utils.h b/googlemock/include/gmock/internal/gmock-internal-utils.h
index 66cf857b..b2df5b47 100644
--- a/googlemock/include/gmock/internal/gmock-internal-utils.h
+++ b/googlemock/include/gmock/internal/gmock-internal-utils.h
@@ -460,6 +460,16 @@ struct Function<R(Args...)> {
 template <typename R, typename... Args>
 constexpr size_t Function<R(Args...)>::ArgumentCount;
 
+// C++11 and 14 compatible invoke_result
+template<typename C, typename... Args>
+struct InvokeResult {
+#ifdef __cpp_lib_is_invocable
+  typedef typename std::invoke_result<C, Args...>::type type;
+#else
+  typedef typename std::result_of<C(Args...)>::type type;
+#endif
+};
+
 #ifdef _MSC_VER
 # pragma warning(pop)
 #endif