QML: Reset the binding name when synthesizing components

The binding that creates the element inside of a Component has no name.

Pick-to: 6.2 6.3
Fixes: QTBUG-101655
Change-Id: Ib2ff272cff4f21efb588553d55d1e348e2ee5f87
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>

src/qml/qml/qqmltypecompiler.cpp

@@ -861,6 +861,10 @@ void QQmlComponentAndAliasResolver::findAndRegisterImplicitComponents(
 
         QmlIR::Binding *syntheticBinding = pool->New<QmlIR::Binding>();
         *syntheticBinding = *binding;
+
+        // The synthetic binding inside Component has no name. It's just "Component { Foo {} }".
+        syntheticBinding->propertyNameIndex = 0;
+
         syntheticBinding->type = QV4::CompiledData::Binding::Type_Object;
         QString error = syntheticComponent->appendBinding(syntheticBinding, /*isListBinding*/false);
         Q_ASSERT(error.isEmpty());

tests/auto/qml/qqmllanguage/data/componentMix.qml

@@ -0,0 +1,13 @@
+import QtQml
+
+QtObject {
+    component View: QtObject {
+        default property Component delegate
+    }
+
+    component Things : QtObject {
+        property QtObject view: View { delegate: QtObject {} }
+    }
+
+    property Things things: Things {}
+}

tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp

@@ -393,6 +393,7 @@ private slots:
     void objectAsBroken();
     void customValueTypes();
     void valueTypeList();
+    void componentMix();
 
 private:
     QQmlEngine engine;
@@ -6892,6 +6893,22 @@ void tst_qqmllanguage::valueTypeList()
     }
 }
 
+void tst_qqmllanguage::componentMix()
+{
+    QQmlEngine engine;
+    QQmlComponent c(&engine, testFileUrl("componentMix.qml"));
+    QVERIFY2(c.isReady(), qPrintable(c.errorString()));
+    QScopedPointer<QObject> o(c.create());
+    QVERIFY(!o.isNull());
+    QObject *things = qvariant_cast<QObject *>(o->property("things"));
+    QVERIFY(things);
+    QObject *view = qvariant_cast<QObject *>(things->property("view"));
+    QVERIFY(view);
+    QObject *delegate = qvariant_cast<QObject *>(view->property("delegate"));
+    QVERIFY(delegate);
+    QCOMPARE(delegate->metaObject(), &QQmlComponent::staticMetaObject);
+}
+
 QTEST_MAIN(tst_qqmllanguage)
 
 #include "tst_qqmllanguage.moc"