diff --git a/src/widgets/kernel/qwidget.h b/src/widgets/kernel/qwidget.h
index a17803cabc3..4591ab04540 100644
--- a/src/widgets/kernel/qwidget.h
+++ b/src/widgets/kernel/qwidget.h
@@ -769,9 +769,6 @@ private:
 #endif // QT_NO_GESTURES
     friend class QWidgetEffectSourcePrivate;
 
-#ifdef Q_OS_MAC
-    friend bool qt_mac_is_metal(const QWidget *w);
-#endif
     friend Q_WIDGETS_EXPORT QWidgetData *qt_qwidget_data(QWidget *widget);
     friend Q_WIDGETS_EXPORT QWidgetPrivate *qt_widget_private(QWidget *widget);