From 375f7a416031b3a011a5a88ba5f80f5879d775ca Mon Sep 17 00:00:00 2001
From: Sam McCall <sam.mccall@gmail.com>
Date: Mon, 19 Oct 2020 14:58:31 +0200
Subject: [PATCH] [ADT] Avoid use of result_of_t in function_ref

It has bugs on some old libc++ versions and we don't need the power.
See https://reviews.llvm.org/D88977
---
 llvm/include/llvm/ADT/STLExtras.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/llvm/include/llvm/ADT/STLExtras.h b/llvm/include/llvm/ADT/STLExtras.h
index 0d18164..f3f9f20 100644
--- a/llvm/include/llvm/ADT/STLExtras.h
+++ b/llvm/include/llvm/ADT/STLExtras.h
@@ -199,9 +199,9 @@ public:
                         function_ref>::value> * = nullptr,
       // Functor must be callable and return a suitable type.
       std::enable_if_t<std::is_void<Ret>::value ||
-                       std::is_convertible<
-                           std::result_of_t<Callable(Params...)>, Ret>::value>
-          * = nullptr)
+                       std::is_convertible<decltype(std::declval<Callable>()(
+                                               std::declval<Params>()...)),
+                                           Ret>::value> * = nullptr)
       : callback(callback_fn<typename std::remove_reference<Callable>::type>),
         callable(reinterpret_cast<intptr_t>(&callable)) {}
 
-- 
2.7.4