From a1889b2a6703161b2206635930b9a82a63123a74 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Tue, 14 Mar 2023 16:23:31 +0100
Subject: [PATCH] Verify fix for manual get<I> calls for QVector<N>D

The necessary QT_ENABLE_P0846_SEMANTICS_FOR is already provided by
qpoint.h) here. Add a test to confirm it works.

Amends 0e22001a3bb070d4e9956e89543ec0e5ac6f23f8.

[ChangeLog][QtGui][QVector2/3/4D] Fixed manual get<I>() calls
(Tuple Protocol) in C++17 mode.

Task-number: QTBUG-111598
Change-Id: Id4a118b6439c2d1471b921f8d92ee558f9902eab
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
---
 src/gui/math3d/qvectornd.h                    |  2 ++
 .../gui/math3d/qvectornd/tst_qvectornd.cpp    | 33 +++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/src/gui/math3d/qvectornd.h b/src/gui/math3d/qvectornd.h
index 639b8f0e5a..a8adf12801 100644
--- a/src/gui/math3d/qvectornd.h
+++ b/src/gui/math3d/qvectornd.h
@@ -15,6 +15,8 @@
 
 QT_BEGIN_NAMESPACE
 
+// QT_ENABLE_P0846_SEMANTICS_FOR(get) // from qpoint.h
+
 class QVector2D;
 class QVector3D;
 class QVector4D;
diff --git a/tests/auto/gui/math3d/qvectornd/tst_qvectornd.cpp b/tests/auto/gui/math3d/qvectornd/tst_qvectornd.cpp
index ade6eba796..beba252293 100644
--- a/tests/auto/gui/math3d/qvectornd/tst_qvectornd.cpp
+++ b/tests/auto/gui/math3d/qvectornd/tst_qvectornd.cpp
@@ -1,6 +1,39 @@
 // Copyright (C) 2016 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
 
+#include <QVector2D>
+#include <QVector3D>
+#include <QVector4D>
+#ifdef QVARIANT_H
+# error "This test requires qvector{2,3,4}d.h to not include qvariant.h"
+#endif
+
+// don't assume <type_traits>
+template <typename T, typename U>
+constexpr inline bool my_is_same_v = false;
+template <typename T>
+constexpr inline bool my_is_same_v<T, T> = true;
+
+#define CHECK(cvref) \
+    static_assert(my_is_same_v<decltype(get<0>(std::declval<QVector2D cvref >())), float cvref >); \
+    static_assert(my_is_same_v<decltype(get<1>(std::declval<QVector2D cvref >())), float cvref >); \
+    \
+    static_assert(my_is_same_v<decltype(get<0>(std::declval<QVector3D cvref >())), float cvref >); \
+    static_assert(my_is_same_v<decltype(get<1>(std::declval<QVector3D cvref >())), float cvref >); \
+    static_assert(my_is_same_v<decltype(get<2>(std::declval<QVector3D cvref >())), float cvref >); \
+    \
+    static_assert(my_is_same_v<decltype(get<0>(std::declval<QVector4D cvref >())), float cvref >); \
+    static_assert(my_is_same_v<decltype(get<1>(std::declval<QVector4D cvref >())), float cvref >); \
+    static_assert(my_is_same_v<decltype(get<2>(std::declval<QVector4D cvref >())), float cvref >); \
+    static_assert(my_is_same_v<decltype(get<3>(std::declval<QVector4D cvref >())), float cvref >)
+
+CHECK(&);
+CHECK(const &);
+CHECK(&&);
+CHECK(const &&);
+
+#undef CHECK
+
 #include <QTest>
 #include <QtCore/qmath.h>
 #include <QtGui/qvector2d.h>