From db3d097db2e2bd5fe545d570b49bfbe0754fbc16 Mon Sep 17 00:00:00 2001
From: Andrei Golubev <andrei.golubev@qt.io>
Date: Thu, 15 Oct 2020 10:02:46 +0200
Subject: [PATCH] Fix subtle SFINAE problem in QPromise::addResult

Accidentally found out that we enable/disable QPromise::addResult based
on type deduced from input argument, instead of using "value_type" of
QPromise itself, which is wrong

Simplified the checks to a single one -
EnableIfSameOrConvertible<InputType, StoredType> as this is sufficient
to account for both cases: QPromise<void> and QPromise<T> with input,
convertible to T

Change-Id: I657998c0e26241b0fc5e70988622984ece8871df
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>
---
 src/corelib/thread/qpromise.h | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/corelib/thread/qpromise.h b/src/corelib/thread/qpromise.h
index 225ce3dee1..68645ef084 100644
--- a/src/corelib/thread/qpromise.h
+++ b/src/corelib/thread/qpromise.h
@@ -86,9 +86,7 @@ public:
 
     // Core QPromise APIs
     QFuture<T> future() const { return d.future(); }
-    template<typename U = T,
-             typename = QtPrivate::EnableForNonVoid<std::decay_t<U>>,
-             typename = QtPrivate::EnableIfSameOrConvertible<std::decay_t<U>, std::decay_t<T>>>
+    template<typename U, typename = QtPrivate::EnableIfSameOrConvertible<U, T>>
     bool addResult(U &&result, int index = -1)
     {
         return d.reportResult(std::forward<U>(result), index);