From c44e3b119af7d306378f3a9085d084c0b7cd21e0 Mon Sep 17 00:00:00 2001
From: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Date: Mon, 6 Sep 2021 17:22:34 +0200
Subject: [PATCH] Add a conditional noexcept specification to qExchange

Following P2401 (which libstdc++ and MS-STL already implement)
and [res.on.exception.handling]/5 that gives us freedom to
strenghten any noexcept specification.

Change-Id: I17ebd9148a181eb8496ace3a9d8010008160b564
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
---
 src/corelib/global/qglobal.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h
index 6467ba1984..3fabac3888 100644
--- a/src/corelib/global/qglobal.h
+++ b/src/corelib/global/qglobal.h
@@ -1204,6 +1204,7 @@ void qAsConst(const T &&) = delete;
 // like std::exchange
 template <typename T, typename U = T>
 constexpr T qExchange(T &t, U &&newValue)
+noexcept(std::conjunction_v<std::is_nothrow_move_constructible<T>, std::is_nothrow_assignable<T &, U>>)
 {
     T old = std::move(t);
     t = std::forward<U>(newValue);