QmlDesigner: Fix crash for QQuickStyleItem

QQuickStyleItem crashes if componentComplete() is called.

Change-Id: I1df1b50f6ba95c0eda1ff8e18de85276a6de04f5
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

share/qtcreator/qml/qmlpuppet/qmlprivategate/qmlprivategate_56.cpp

@@ -167,6 +167,26 @@ void registerNodeInstanceMetaObject(QObject *object, QQmlEngine *engine)
     QQuickDesignerSupportProperties::registerNodeInstanceMetaObject(object, engine);
 }
 
+static bool isQuickStyleItemMetaObject(const QMetaObject *metaObject)
+{
+    if (metaObject) {
+        if (metaObject->className() == QByteArrayLiteral("QQuickStyleItem"))
+            return true;
+
+        return isQuickStyleItemMetaObject(metaObject->superClass());
+    }
+
+    return false;
+}
+
+static bool isQuickStyleItem(QObject *object)
+{
+    if (object)
+        return isQuickStyleItemMetaObject(object->metaObject());
+
+    return false;
+}
+
 // This is used in share/qtcreator/qml/qmlpuppet/qml2puppet/instances/objectnodeinstance.cpp
 QObject *createPrimitive(const QString &typeName, int majorNumber, int minorNumber, QQmlContext *context)
 {
@@ -357,6 +377,8 @@ void doComponentCompleteRecursive(QObject *object, NodeInstanceServer *nodeInsta
                 doComponentCompleteRecursive(child, nodeInstanceServer);
         }
 
+        if (!isQuickStyleItem(item)) {
+            qDebug() << Q_FUNC_INFO << item;
             if (item) {
                 static_cast<QQmlParserStatus *>(item)->componentComplete();
             } else {
@@ -366,6 +388,7 @@ void doComponentCompleteRecursive(QObject *object, NodeInstanceServer *nodeInsta
             }
         }
     }
+}
 
 
 void keepBindingFromGettingDeleted(QObject *object, QQmlContext *context, const PropertyName &propertyName)