Teach QML that it is possible to treat custom QObjects as QObject

It is always better to treat a QObject child as QObject then a QVariant.

Change-Id: I4ac069e85232dd4d1411e325bc5b858bd001f9a6
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

2 files changed, 15 insertions, 3 deletions

diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index f90a693265..3d6a13d794 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -1660,9 +1660,13 @@ QV4::ReturnedValue ExecutionEngine::metaTypeToJS(int type, const void *data)
                 return QV4::Encode::null();
             }
             QMetaType mt(type);
-            if (mt.flags() & QMetaType::IsGadget) {
-                Q_ASSERT(mt.metaObject());
-                return QV4::QQmlValueTypeWrapper::create(this, QVariant(type, data), mt.metaObject(), type);
+            if (auto metaObject = mt.metaObject()) {
+                auto flags = mt.flags();
+                if (flags & QMetaType::IsGadget) {
+                    return QV4::QQmlValueTypeWrapper::create(this, QVariant(type, data), metaObject, type);
+                } else if (flags & QMetaType::PointerToQObject) {
+                    return QV4::QObjectWrapper::wrap(this, *reinterpret_cast<QObject* const *>(data));
+                }
             }
             if (QMetaType::hasRegisteredConverterFunction(type, qMetaTypeId<QtMetaTypePrivate::QSequentialIterableImpl>())) {
                 auto v = QVariant(type, data);
diff --git a/tests/auto/qml/qqmlvaluetypes/tst_qqmlvaluetypes.cpp b/tests/auto/qml/qqmlvaluetypes/tst_qqmlvaluetypes.cpp
index 5cff44c3cc..6ccfc77c25 100644
--- a/tests/auto/qml/qqmlvaluetypes/tst_qqmlvaluetypes.cpp
+++ b/tests/auto/qml/qqmlvaluetypes/tst_qqmlvaluetypes.cpp
@@ -1720,6 +1720,14 @@ void tst_qqmlvaluetypes::sequences()
         for (int i = 0; i < objSet.size(); ++i)
             QCOMPARE(value.property(i).property("point").property("x").toInt(), a.point().x());
     }
+    {
+        MyTypeObject a, b, c;
+        QSet<MyTypeObject*> container{&a, &b, &c};
+        QJSValue value = engine.toScriptValue(container);
+        QCOMPARE(value.property("length").toInt(), container.size());
+        for (int i = 0; i < container.size(); ++i)
+            QCOMPARE(value.property(i).property("point").property("x").toInt(), a.point().x());
+    }
 }
 struct StringLessGadget {
     Q_GADGET