diff --git a/src/plugins/platforms/cocoa/qcocoaapplication.mm b/src/plugins/platforms/cocoa/qcocoaapplication.mm
index 79399e4183..227ab05c25 100644
--- a/src/plugins/platforms/cocoa/qcocoaapplication.mm
+++ b/src/plugins/platforms/cocoa/qcocoaapplication.mm
@@ -133,7 +133,7 @@ static const QByteArray q_macLocalEventType = QByteArrayLiteral("mac_generic_NSE
         return true;
 
     if ([event type] == NSApplicationDefined) {
-        switch ([event subtype]) {
+        switch (static_cast<short>([event subtype])) {
             case QtCocoaEventSubTypePostMessage:
                 [NSApp QT_MANGLE_NAMESPACE(qt_sendPostedMessage):event];
                 return true;