qml: Override the new Object::instanceOf hook to allow QML type checking

[ChangeLog][QtQml] The instanceof keyword in JavaScript has been
extended to work on QML types and instances. This means that you are now
able to use it to verify that a var is indeed the type you expect (e.g.
someVar instanceof Rectangle).

Note that one of the added tests revealed a slight shortcoming in the
QML type system (QTBUG-58477). For now, we should keep consistency and
work to address the problem universally in the future.

Change-Id: I7d9bf9b64cfd037908de1ae51b01065eacb95abe
Task-number: QTBUG-24799
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 13 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmllanguage/data/instanceof_qtqml.qml b/tests/auto/qml/qqmllanguage/data/instanceof_qtqml.qml
new file mode 100644
index 0000000000..d74b172cf8
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/instanceof_qtqml.qml
@@ -0,0 +1,13 @@
+import QtQml 2.0
+
+QtObject {
+    id: qtobjectInstance
+
+    property Timer aTimer: Timer {
+        id: timerInstance
+    }
+
+    property Connections aConnections: Connections {
+        id: connectionsInstance
+    }
+}