3 files changed, 26 insertions, 4 deletions
diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index c25f67faf8..8131c314d7 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -125,6 +125,7 @@
 #include <qtgui_tracepoints_p.h>
 
 #include <ctype.h>
+#include <limits>
 
 QT_BEGIN_NAMESPACE
 
@@ -142,7 +143,7 @@ Q_GUI_EXPORT bool qt_is_gui_used = true;
 Qt::MouseButtons QGuiApplicationPrivate::mouse_buttons = Qt::NoButton;
 Qt::KeyboardModifiers QGuiApplicationPrivate::modifier_buttons = Qt::NoModifier;
 
-QPointF QGuiApplicationPrivate::lastCursorPosition(qt_inf(), qt_inf());
+QGuiApplicationPrivate::QLastCursorPosition QGuiApplicationPrivate::lastCursorPosition;
 
 QWindow *QGuiApplicationPrivate::currentMouseWindow = nullptr;
 
@@ -704,7 +705,7 @@ QGuiApplication::~QGuiApplication()
     QGuiApplicationPrivate::desktopFileName = nullptr;
     QGuiApplicationPrivate::mouse_buttons = Qt::NoButton;
     QGuiApplicationPrivate::modifier_buttons = Qt::NoModifier;
-    QGuiApplicationPrivate::lastCursorPosition = {qreal(qInf()), qreal(qInf())};
+    QGuiApplicationPrivate::lastCursorPosition.reset();
     QGuiApplicationPrivate::currentMousePressWindow = QGuiApplicationPrivate::currentMouseWindow = nullptr;
     QGuiApplicationPrivate::applicationState = Qt::ApplicationInactive;
     QGuiApplicationPrivate::currentDragWindow = nullptr;
@@ -4140,6 +4141,14 @@ QPixmap QGuiApplicationPrivate::getPixmapCursor(Qt::CursorShape cshape)
     return QPixmap();
 }
 
+QPoint QGuiApplicationPrivate::QLastCursorPosition::toPoint() const noexcept
+{
+    // Guard against the default initialization of qInf() (avoid UB or SIGFPE in conversion).
+    if (Q_UNLIKELY(qIsInf(thePoint.x())))
+        return QPoint(std::numeric_limits<int>::max(), std::numeric_limits<int>::max());
+    return thePoint.toPoint();
+}
+
 void QGuiApplicationPrivate::notifyThemeChanged()
 {
     updatePalette();
diff --git a/src/gui/kernel/qguiapplication_p.h b/src/gui/kernel/qguiapplication_p.h
index 5845d98374..a6c48c2bae 100644
--- a/src/gui/kernel/qguiapplication_p.h
+++ b/src/gui/kernel/qguiapplication_p.h
@@ -61,6 +61,7 @@
 
 #include <QtCore/qnativeinterface.h>
 #include <QtCore/private/qnativeinterface_p.h>
+#include <QtCore/private/qnumeric_p.h>
 #include <QtCore/private/qthread_p.h>
 
 #include <qpa/qwindowsysteminterface.h>
@@ -225,7 +226,19 @@ public:
     virtual bool popupActive() { return false; }
 
     static Qt::MouseButton mousePressButton;
-    static QPointF lastCursorPosition;
+    static struct QLastCursorPosition {
+        constexpr inline QLastCursorPosition() noexcept : thePoint(qt_inf(), qt_inf()) {}
+        constexpr inline Q_IMPLICIT QLastCursorPosition(QPointF p) noexcept : thePoint(p) {}
+        constexpr inline Q_IMPLICIT operator QPointF() const noexcept { return thePoint; }
+        constexpr inline qreal x() const noexcept{ return thePoint.x(); }
+        constexpr inline qreal y() const noexcept{ return thePoint.y(); }
+        Q_GUI_EXPORT QPoint toPoint() const noexcept;
+
+        constexpr void reset() noexcept { *this = QLastCursorPosition{}; }
+
+    private:
+        QPointF thePoint;
+    } lastCursorPosition;
     static QWindow *currentMouseWindow;
     static QWindow *currentMousePressWindow;
     static Qt::ApplicationState applicationState;
diff --git a/src/widgets/kernel/qwidgetwindow.cpp b/src/widgets/kernel/qwidgetwindow.cpp
index 1501407a42..066c8b552f 100644
--- a/src/widgets/kernel/qwidgetwindow.cpp
+++ b/src/widgets/kernel/qwidgetwindow.cpp
@@ -413,7 +413,7 @@ void QWidgetWindow::handleEnterLeaveEvent(QEvent *event)
         QWindowSystemInterfacePrivate::EnterEvent *systemEvent =
             static_cast<QWindowSystemInterfacePrivate::EnterEvent *>
             (QWindowSystemInterfacePrivate::peekWindowSystemEvent(QWindowSystemInterfacePrivate::Enter));
-        const QPointF globalPosF = systemEvent ? systemEvent->globalPos : QGuiApplicationPrivate::lastCursorPosition;
+        const QPointF globalPosF = systemEvent ? systemEvent->globalPos : QPointF(QGuiApplicationPrivate::lastCursorPosition);
         if (systemEvent) {
             if (QWidgetWindow *enterWindow = qobject_cast<QWidgetWindow *>(systemEvent->enter))
             {