From 31d2aa4e8199492308d2e25429abea3c1483ccd7 Mon Sep 17 00:00:00 2001
From: Richard Barnes <rbarnes@meta.com>
Date: Mon, 6 May 2024 01:06:35 -0700
Subject: [PATCH] Change `result_of` to `invoke_result` in
 fatal/container/legacy_variant.h

Summary: C++20 has [eliminated](https://en.cppreference.com/w/cpp/types/result_of) `result_of` in favour of `invoke_result`. It's mysterious that this code even still works, but, nevertheless, I'm fixing it.

Differential Revision: D56987396

fbshipit-source-id: 71ca954c5825fb8f0e1939e51c77fe700b1dff20
---
 fatal/container/legacy_variant.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fatal/container/legacy_variant.h b/fatal/container/legacy_variant.h
index 11769d51..49bf5434 100644
--- a/fatal/container/legacy_variant.h
+++ b/fatal/container/legacy_variant.h
@@ -1283,7 +1283,7 @@ struct legacy_variant {
   template <typename UCallable, typename... UArgs, typename std::enable_if<
     is_supported<
       typename std::decay<
-        typename std::result_of<UCallable&(UArgs...)>::type
+        typename std::invoke_result<UCallable&, UArgs...>::type
       >::type
     >(), int
   >::type = 0>
@@ -1295,7 +1295,7 @@ struct legacy_variant {
   template <typename UCallable, typename... UArgs, typename std::enable_if<
     !is_supported<
       typename std::decay<
-        typename std::result_of<UCallable&(UArgs...)>::type
+        typename std::invoke_result<UCallable&, UArgs...>::type
       >::type
     >(), int
   >::type = 0>