From 7fdf7ad7e578675b32deb399b51ec6392c66cb2d Mon Sep 17 00:00:00 2001
From: Christian Ehrlicher <ch.ehrlicher@gmx.de>
Date: Tue, 1 Apr 2025 21:36:13 +0200
Subject: [PATCH] Windows11Style: replace QObject::inherits() with
 qobject_cast<>

Use qobject_cast<QComboBoxPrivateContainer *> instead
QObject::inherits() as this should be slightly faster and we have access
to the type so no need to use error-prone string comparison.

Pick-to: 6.9 6.8
Task-number: QTBUG-135340
Change-Id: I90ebb2323f21c2f5f9dd65bd7b1beeb32f1a91cc
Reviewed-by: Wladimir Leuschner <wladimir.leuschner@qt.io>
---
 src/plugins/styles/modernwindows/qwindows11style.cpp | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/plugins/styles/modernwindows/qwindows11style.cpp b/src/plugins/styles/modernwindows/qwindows11style.cpp
index ac98aaa5900..7566e00fd9e 100644
--- a/src/plugins/styles/modernwindows/qwindows11style.cpp
+++ b/src/plugins/styles/modernwindows/qwindows11style.cpp
@@ -7,6 +7,7 @@
 #include <private/qstyle_p.h>
 #include <private/qstylehelper_p.h>
 #include <private/qapplication_p.h>
+#include <private/qcombobox_p.h>
 #include <qstyleoption.h>
 #include <qpainter.h>
 #include <QGraphicsDropShadowEffect>
@@ -978,7 +979,7 @@ void QWindows11Style::drawPrimitive(PrimitiveElement element, const QStyleOption
             if (frame->frameShape == QFrame::NoFrame)
                 break;
             QRectF rect = option->rect.adjusted(1,1,-1,-1);
-            if (widget && widget->inherits("QComboBoxPrivateContainer")) {
+            if (qobject_cast<const QComboBoxPrivateContainer *>(widget)) {
                 painter->setPen(Qt::NoPen);
                 painter->setBrush(WINUI3Colors[colorSchemeIndex][menuPanelFill]);
                 painter->drawRoundedRect(rect, secondLevelRoundingRadius, secondLevelRoundingRadius);
@@ -1853,8 +1854,7 @@ QRect QWindows11Style::subElementRect(QStyle::SubElement element, const QStyleOp
         if (const auto *item = qstyleoption_cast<const QStyleOptionViewItem *>(option)) {
             const int decorationOffset = item->features.testFlag(QStyleOptionViewItem::HasDecoration) ? item->decorationSize.width() : 0;
             const int checkboxOffset = item->features.testFlag(QStyleOptionViewItem::HasCheckIndicator) ? 16 : 0;
-            if (widget && widget->parentWidget()
-             && widget->parentWidget()->inherits("QComboBoxPrivateContainer")) {
+            if (widget && qobject_cast<QComboBoxPrivateContainer *>(widget->parentWidget())) {
                 if (option->direction == Qt::LeftToRight)
                     ret = option->rect.adjusted(decorationOffset + checkboxOffset + 5, 0, -5, 0);
                 else
@@ -2197,7 +2197,8 @@ void QWindows11Style::polish(QWidget* widget)
     if (!qobject_cast<QCommandLinkButton *>(widget))
         QWindowsVistaStyle::polish(widget);
     const bool isScrollBar = qobject_cast<QScrollBar *>(widget);
-    if (isScrollBar || qobject_cast<QMenu *>(widget) || widget->inherits("QComboBoxPrivateContainer")) {
+    const auto comboBoxContainer = qobject_cast<const QComboBoxPrivateContainer *>(widget);
+    if (isScrollBar || qobject_cast<QMenu *>(widget) || comboBoxContainer) {
         bool wasCreated = widget->testAttribute(Qt::WA_WState_Created);
         bool layoutDirection = widget->testAttribute(Qt::WA_RightToLeft);
         widget->setAttribute(Qt::WA_OpaquePaintEvent,false);