From bd641fb00551e3897d31452fb1191af0f0cb837c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=B6nke=20K=2E=20Schau?= <github@schau.org>
Date: Tue, 25 Jan 2022 12:01:53 +0100
Subject: [PATCH] Replace std::result_of with std::invoke_result for C++17
 compiles

---
 3rd_party/include/opentracing/variant/variant.hpp | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/3rd_party/include/opentracing/variant/variant.hpp b/3rd_party/include/opentracing/variant/variant.hpp
index 7b6bb47..eb2c619 100644
--- a/3rd_party/include/opentracing/variant/variant.hpp
+++ b/3rd_party/include/opentracing/variant/variant.hpp
@@ -167,7 +167,11 @@ struct enable_if_type
 template <typename F, typename V, typename Enable = void>
 struct result_of_unary_visit
 {
-    using type = typename std::result_of<F(V&)>::type;
+#ifdef __cpp_lib_is_invocable
+                using type = typename std::invoke_result<F, V&>::type;
+#else
+                using type = typename std::result_of<F(V&)>::type;
+#endif
 };
 
 template <typename F, typename V>
@@ -179,7 +183,11 @@ struct result_of_unary_visit<F, V, typename enable_if_type<typename F::result_ty
 template <typename F, typename V, typename Enable = void>
 struct result_of_binary_visit
 {
-    using type = typename std::result_of<F(V&, V&)>::type;
+#ifdef __cpp_lib_is_invocable
+                using type = typename std::invoke_result<F, V&, V&>::type;
+#else
+                using type = typename std::result_of<F(V&, V&)>::type;
+#endif
 };
 
 template <typename F, typename V>