Add QQmlEngine::trimComponentCache()

Allow unused data in the engine's component cache to be safely discarded
so that the memory can be freed for other purposes.

Unloading of scripts that are no longer required after trimming unused
components is not yet supported.

Task-number: QTBUG-25653
Change-Id: I37bc9d5592eeb5edceeb34d010a555dcffd11cea
Reviewed-by: Michael Brasser <michael.brasser@nokia.com>

81 files changed, 2178 insertions, 144 deletions

diff --git a/src/qml/qml/ftw/qqmlrefcount_p.h b/src/qml/qml/ftw/qqmlrefcount_p.h
index 497f4ecc0f..ce94f1af35 100644
--- a/src/qml/qml/ftw/qqmlrefcount_p.h
+++ b/src/qml/qml/ftw/qqmlrefcount_p.h
@@ -68,6 +68,7 @@ public:
     inline virtual ~QQmlRefCount();
     inline void addref();
     inline void release();
+    inline int count() const;
 
 protected:
     inline virtual void destroy();
@@ -124,6 +125,11 @@ void QQmlRefCount::release()
         destroy(); 
 }
 
+int QQmlRefCount::count() const
+{
+    return refCount.load();
+}
+
 void QQmlRefCount::destroy() 
 { 
     delete this; 
diff --git a/src/qml/qml/qqmlbinding.cpp b/src/qml/qml/qqmlbinding.cpp
index 1e25c15b09..2c2c801594 100644
--- a/src/qml/qml/qqmlbinding.cpp
+++ b/src/qml/qml/qqmlbinding.cpp
@@ -65,21 +65,21 @@ QQmlBinding::createBinding(Identifier id, QObject *obj, QQmlContext *ctxt,
     if (id < 0)
         return 0;
 
-    QQmlContextData *ctxtdata = QQmlContextData::get(ctxt);
+    QQmlBinding *rv = 0;
 
+    QQmlContextData *ctxtdata = QQmlContextData::get(ctxt);
     QQmlEnginePrivate *engine = QQmlEnginePrivate::get(ctxt->engine());
-    QQmlCompiledData *cdata = 0;
-    QQmlTypeData *typeData = 0;
     if (engine && ctxtdata && !ctxtdata->url.isEmpty()) {
-        typeData = engine->typeLoader.get(ctxtdata->url);
-        cdata = typeData->compiledData();
-    }
-    QQmlBinding *rv = cdata ? new QQmlBinding(cdata->primitives.at(id), true, obj, ctxtdata,
-                                              url, lineNumber, 0) : 0;
-    if (cdata)
-        cdata->release();
-    if (typeData)
+        QQmlTypeData *typeData = engine->typeLoader.getType(ctxtdata->url);
+        Q_ASSERT(typeData);
+
+        if (QQmlCompiledData *cdata = typeData->compiledData()) {
+            rv = new QQmlBinding(cdata->primitives.at(id), true, obj, ctxtdata, url, lineNumber, 0);
+        }
+
         typeData->release();
+    }
+
     return rv;
 }
 
diff --git a/src/qml/qml/qqmlcompiler.cpp b/src/qml/qml/qqmlcompiler.cpp
index 2275b559b5..c423d933d0 100644
--- a/src/qml/qml/qqmlcompiler.cpp
+++ b/src/qml/qml/qqmlcompiler.cpp
@@ -807,6 +807,7 @@ bool QQmlCompiler::compile(QQmlEngine *engine,
 
         } else if (tref.typeData) {
             ref.component = tref.typeData->compiledData();
+            ref.component->addref();
         }
         out->types << ref;
     }
@@ -921,7 +922,7 @@ void QQmlCompiler::compileTree(QQmlScript::Object *tree)
         output->root = &output->rootData;
     }
     if (!tree->metadata.isEmpty()) 
-        enginePrivate->registerCompositeType(output);
+        enginePrivate->registerCompositeType(output->root);
 }
 
 static bool QStringList_contains(const QStringList &list, const QHashedStringRef &string)
@@ -2878,13 +2879,10 @@ bool QQmlCompiler::buildDynamicMeta(QQmlScript::Object *obj, DynamicMetaMode mod
                     COMPILE_EXCEPTION(p, tr("Invalid property type"));
 
                 if (!qmltype) {
-                    QQmlTypeData *tdata = enginePrivate->typeLoader.get(QUrl(url));
+                    QQmlTypeData *tdata = enginePrivate->typeLoader.getType(QUrl(url));
                     Q_ASSERT(tdata);
                     Q_ASSERT(tdata->isComplete());
-
-                    QQmlCompiledData *data = tdata->compiledData();
-                    customTypeName = data->root->className();
-                    data->release();
+                    customTypeName = tdata->compiledData()->root->className();
                     tdata->release();
                 } else {
                     customTypeName = qmltype->typeName();
diff --git a/src/qml/qml/qqmlcomponent.cpp b/src/qml/qml/qqmlcomponent.cpp
index ffa08c3ad5..f82f1d281e 100644
--- a/src/qml/qml/qqmlcomponent.cpp
+++ b/src/qml/qml/qqmlcomponent.cpp
@@ -327,6 +327,7 @@ void QQmlComponentPrivate::fromTypeData(QQmlTypeData *data)
         state.errors = data->errors();
     } else {
         cc = c;
+        cc->addref();
     }
 
     data->release();
@@ -573,7 +574,7 @@ void QQmlComponent::setData(const QByteArray &data, const QUrl &url)
 
     d->url = url;
 
-    QQmlTypeData *typeData = QQmlEnginePrivate::get(d->engine)->typeLoader.get(data, url);
+    QQmlTypeData *typeData = QQmlEnginePrivate::get(d->engine)->typeLoader.getType(data, url);
     
     if (typeData->isCompleteOrError()) {
         d->fromTypeData(typeData);
@@ -652,7 +653,7 @@ void QQmlComponentPrivate::loadUrl(const QUrl &newUrl, QQmlComponent::Compilatio
             ? QQmlDataLoader::Asynchronous
             : QQmlDataLoader::PreferSynchronous;
 
-    QQmlTypeData *data = QQmlEnginePrivate::get(engine)->typeLoader.get(url, loaderMode);
+    QQmlTypeData *data = QQmlEnginePrivate::get(engine)->typeLoader.getType(url, loaderMode);
 
     if (data->isCompleteOrError()) {
         fromTypeData(data);
@@ -982,7 +983,8 @@ void QQmlComponent::create(QQmlIncubator &i, QQmlContext *context,
 
     QQmlEnginePrivate *enginePriv = QQmlEnginePrivate::get(d->engine);
 
-    p->component = d->cc; p->component->addref();
+    p->compiledData = d->cc;
+    p->compiledData->addref();
     p->vme.init(contextData, d->cc, d->start, d->creationContext);
 
     enginePriv->incubate(i, forContextData);
diff --git a/src/qml/qml/qqmldata_p.h b/src/qml/qml/qqmldata_p.h
index 12344e3a6b..f7180b9332 100644
--- a/src/qml/qml/qqmldata_p.h
+++ b/src/qml/qml/qqmldata_p.h
@@ -81,7 +81,7 @@ public:
         : ownMemory(true), ownContext(false), indestructible(true), explicitIndestructibleSet(false), 
           hasTaintedV8Object(false), isQueuedForDeletion(false), rootObjectInCreation(false), notifyList(0), context(0), outerContext(0),
           bindings(0), signalHandlers(0), nextContextObject(0), prevContextObject(0), bindingBitsSize(0), bindingBits(0),
-          lineNumber(0), columnNumber(0), deferredComponent(0), deferredIdx(0), v8objectid(0), 
+          lineNumber(0), columnNumber(0), compiledData(0), deferredIdx(0), v8objectid(0),
           propertyCache(0), guards(0), extendedData(0) {
         init();
     }
@@ -162,7 +162,7 @@ public:
     ushort lineNumber;
     ushort columnNumber;
 
-    QQmlCompiledData *deferredComponent; // Can't this be found from the context?
+    QQmlCompiledData *compiledData;
     unsigned int deferredIdx;
 
     quint32 v8objectid;
diff --git a/src/qml/qml/qqmlengine.cpp b/src/qml/qml/qqmlengine.cpp
index 788d5edb51..d3ca1b343c 100644
--- a/src/qml/qml/qqmlengine.cpp
+++ b/src/qml/qml/qqmlengine.cpp
@@ -429,8 +429,6 @@ QQmlEnginePrivate::~QQmlEnginePrivate()
     delete rootContext;
     rootContext = 0;
 
-    for(QHash<int, QQmlCompiledData*>::ConstIterator iter = m_compositeTypes.constBegin(); iter != m_compositeTypes.constEnd(); ++iter)
-        (*iter)->release();
     for(QHash<const QMetaObject *, QQmlPropertyCache *>::Iterator iter = propertyCache.begin(); iter != propertyCache.end(); ++iter)
         (*iter)->release();
     for(QHash<QPair<QQmlType *, int>, QQmlPropertyCache *>::Iterator iter = typePropertyCache.begin(); iter != typePropertyCache.end(); ++iter)
@@ -716,11 +714,31 @@ QQmlEngine::~QQmlEngine()
 
   Once the component cache has been cleared, components must be loaded before
   any new objects can be created.
+
+  \sa trimComponentCache()
  */
 void QQmlEngine::clearComponentCache()
 {
     Q_D(QQmlEngine);
-    d->typeLoader.clearCache();
+    d->clearCache();
+}
+
+/*!
+  Trims the engine's internal component cache.
+
+  This function causes the property metadata of any loaded components which are
+  not currently in use to be destroyed.
+
+  A component is considered to be in use if there are any extant instances of
+  the component itself, any instances of other components that use the component,
+  or any objects instantiated by any of those components.
+
+  \sa clearComponentCache()
+ */
+void QQmlEngine::trimComponentCache()
+{
+    Q_D(QQmlEngine);
+    d->trimCache();
 }
 
 /*!
@@ -1074,7 +1092,7 @@ Q_AUTOTEST_EXPORT void qmlExecuteDeferred(QObject *object)
 {
     QQmlData *data = QQmlData::get(object);
 
-    if (data && data->deferredComponent) {
+    if (data && data->compiledData && data->deferredIdx) {
         QQmlObjectCreatingProfiler prof;
         if (prof.enabled) {
             QQmlType *type = QQmlMetaType::qmlType(object->metaObject());
@@ -1088,8 +1106,9 @@ Q_AUTOTEST_EXPORT void qmlExecuteDeferred(QObject *object)
         QQmlComponentPrivate::ConstructionState state;
         QQmlComponentPrivate::beginDeferred(ep, object, &state);
 
-        data->deferredComponent->release();
-        data->deferredComponent = 0;
+        // Release the reference for the deferral action (we still have one from construction)
+        data->compiledData->release();
+        data->compiledData = 0;
 
         QQmlComponentPrivate::complete(ep, &state);
     }
@@ -1267,9 +1286,6 @@ QHash<int, QObject *> *QQmlData::attachedProperties() const
 
 void QQmlData::destroyed(QObject *object)
 {
-    if (deferredComponent)
-        deferredComponent->release();
-
     if (nextContextObject)
         nextContextObject->prevContextObject = prevContextObject;
     if (prevContextObject)
@@ -1284,6 +1300,11 @@ void QQmlData::destroyed(QObject *object)
         binding = next;
     }
 
+    if (compiledData) {
+        compiledData->release();
+        compiledData = 0;
+    }
+
     QQmlAbstractBoundSignal *signalHandler = signalHandlers;
     while (signalHandler) {
         QQmlAbstractBoundSignal *next = signalHandler->m_nextSignal;
@@ -1835,9 +1856,9 @@ int QQmlEnginePrivate::listType(int t) const
 const QMetaObject *QQmlEnginePrivate::rawMetaObjectForType(int t) const
 {
     Locker locker(this);
-    QHash<int, QQmlCompiledData*>::ConstIterator iter = m_compositeTypes.find(t);
+    QHash<int, const QMetaObject *>::ConstIterator iter = m_compositeTypes.find(t);
     if (iter != m_compositeTypes.end()) {
-        return (*iter)->root;
+        return *iter;
     } else {
         QQmlType *type = QQmlMetaType::qmlType(t);
         return type?type->baseMetaObject():0;
@@ -1847,18 +1868,18 @@ const QMetaObject *QQmlEnginePrivate::rawMetaObjectForType(int t) const
 const QMetaObject *QQmlEnginePrivate::metaObjectForType(int t) const
 {
     Locker locker(this);
-    QHash<int, QQmlCompiledData*>::ConstIterator iter = m_compositeTypes.find(t);
+    QHash<int, const QMetaObject *>::ConstIterator iter = m_compositeTypes.find(t);
     if (iter != m_compositeTypes.end()) {
-        return (*iter)->root;
+        return *iter;
     } else {
         QQmlType *type = QQmlMetaType::qmlType(t);
         return type?type->metaObject():0;
     }
 }
 
-void QQmlEnginePrivate::registerCompositeType(QQmlCompiledData *data)
+void QQmlEnginePrivate::registerCompositeType(const QMetaObject *mo)
 {
-    QByteArray name = data->root->className();
+    QByteArray name = mo->className();
 
     QByteArray ptr = name + '*';
     QByteArray lst = "QQmlListProperty<" + name + '>';
@@ -1870,7 +1891,7 @@ void QQmlEnginePrivate::registerCompositeType(QQmlCompiledData *data)
                                                      qMetaTypeConstructHelper<QObject*>,
                                                      sizeof(QObject*),
                                                      static_cast<QFlags<QMetaType::TypeFlag> >(QtPrivate::QMetaTypeTypeFlags<QObject*>::Flags),
-                                                     data->root);
+                                                     mo);
     int lst_type = QMetaType::registerNormalizedType(lst,
                                                      qMetaTypeDeleteHelper<QQmlListProperty<QObject> >,
                                                      qMetaTypeCreateHelper<QQmlListProperty<QObject> >,
@@ -1880,11 +1901,49 @@ void QQmlEnginePrivate::registerCompositeType(QQmlCompiledData *data)
                                                      static_cast<QFlags<QMetaType::TypeFlag> >(QtPrivate::QMetaTypeTypeFlags<QQmlListProperty<QObject> >::Flags),
                                                      static_cast<QMetaObject*>(0));
 
-    data->addref();
-
     Locker locker(this);
     m_qmlLists.insert(lst_type, ptr_type);
-    m_compositeTypes.insert(ptr_type, data);
+    m_compositeTypes.insert(ptr_type, mo);
+}
+
+void QQmlEnginePrivate::unregisterCompositeType(const QMetaObject *mo)
+{
+    QByteArray name = mo->className();
+
+    QByteArray ptr = name + '*';
+    QByteArray lst = "QQmlListProperty<" + name + '>';
+
+    int ptr_type = QMetaType::type(ptr.constData());
+    int lst_type = QMetaType::type(lst.constData());
+
+    Locker locker(this);
+    m_qmlLists.remove(lst_type);
+    m_compositeTypes.remove(ptr_type);
+}
+
+void QQmlEnginePrivate::clearCache()
+{
+    typeLoader.clearCache(this, &QQmlEnginePrivate::typeUnloaded);
+}
+
+void QQmlEnginePrivate::trimCache()
+{
+    typeLoader.trimCache(this, &QQmlEnginePrivate::typeUnloaded);
+}
+
+void QQmlEnginePrivate::typeUnloaded(QQmlTypeData *typeData)
+{
+    unregisterCompositeType(typeData->compiledData()->root);
+}
+
+bool QQmlEnginePrivate::isTypeLoaded(const QUrl &url) const
+{
+    return typeLoader.isTypeLoaded(url);
+}
+
+bool QQmlEnginePrivate::isScriptLoaded(const QUrl &url) const
+{
+    return typeLoader.isScriptLoaded(url);
 }
 
 bool QQml_isFileCaseCorrect(const QString &fileName)
diff --git a/src/qml/qml/qqmlengine.h b/src/qml/qml/qqmlengine.h
index 8640f1acad..f2b7f299a0 100644
--- a/src/qml/qml/qqmlengine.h
+++ b/src/qml/qml/qqmlengine.h
@@ -102,6 +102,7 @@ public:
     QQmlContext *rootContext() const;
 
     void clearComponentCache();
+    void trimComponentCache();
 
     QStringList importPathList() const;
     void setImportPathList(const QStringList &paths);
diff --git a/src/qml/qml/qqmlengine_p.h b/src/qml/qml/qqmlengine_p.h
index 4c6b3b5f0f..d3e7bc2e4d 100644
--- a/src/qml/qml/qqmlengine_p.h
+++ b/src/qml/qml/qqmlengine_p.h
@@ -239,7 +239,14 @@ public:
     int listType(int) const;
     const QMetaObject *rawMetaObjectForType(int) const;
     const QMetaObject *metaObjectForType(int) const;
-    void registerCompositeType(QQmlCompiledData *);
+    void registerCompositeType(const QMetaObject *);
+    void unregisterCompositeType(const QMetaObject *);
+
+    void clearCache();
+    void trimCache();
+
+    bool isTypeLoaded(const QUrl &url) const;
+    bool isScriptLoaded(const QUrl &url) const;
 
     inline void setDebugChangesCache(const QHash<QUrl, QByteArray> &changes);
     inline QHash<QUrl, QByteArray> debugChangesCache();
@@ -295,13 +302,15 @@ private:
     QQmlPropertyCache *createCache(const QMetaObject *);
     QQmlPropertyCache *createCache(QQmlType *, int, QQmlError &error);
 
+    void typeUnloaded(QQmlTypeData *typeData);
+
     // These members must be protected by a QQmlEnginePrivate::Locker as they are required by
     // the threaded loader.  Only access them through their respective accessor methods.
     QHash<QQmlMetaType::ModuleApi, QQmlMetaType::ModuleApiInstance *> moduleApiInstances;
     QHash<const QMetaObject *, QQmlPropertyCache *> propertyCache;
     QHash<QPair<QQmlType *, int>, QQmlPropertyCache *> typePropertyCache;
     QHash<int, int> m_qmlLists;
-    QHash<int, QQmlCompiledData *> m_compositeTypes;
+    QHash<int, const QMetaObject *> m_compositeTypes;
     QHash<QUrl, QByteArray> debugChangesHash;
 
     // These members is protected by the full QQmlEnginePrivate::mutex mutex
diff --git a/src/qml/qml/qqmlexpression.cpp b/src/qml/qml/qqmlexpression.cpp
index 89aa6b3906..d2842f7f4d 100644
--- a/src/qml/qml/qqmlexpression.cpp
+++ b/src/qml/qml/qqmlexpression.cpp
@@ -220,32 +220,24 @@ QQmlExpression::QQmlExpression(const QQmlScriptString &script, QObject *parent)
     if (!script.context()->isValid())
         return;
 
-    bool defaultConstruction = false;
+    bool defaultConstruction = true;
 
     int id = script.d.data()->bindingId;
-    if (id < 0) {
-        defaultConstruction = true;
-    } else {
+    if (id >= 0) {
         QQmlContextData *ctxtdata = QQmlContextData::get(script.context());
-
         QQmlEnginePrivate *engine = QQmlEnginePrivate::get(script.context()->engine());
-        QQmlCompiledData *cdata = 0;
-        QQmlTypeData *typeData = 0;
         if (engine && ctxtdata && !ctxtdata->url.isEmpty()) {
-            typeData = engine->typeLoader.get(ctxtdata->url);
-            cdata = typeData->compiledData();
-        }
+            QQmlTypeData *typeData = engine->typeLoader.getType(ctxtdata->url);
+            Q_ASSERT(typeData);
 
-        if (cdata)
-            d->init(ctxtdata, cdata->primitives.at(id), true, script.scopeObject(),
-                    cdata->name, script.d.data()->lineNumber, script.d.data()->columnNumber);
-        else
-           defaultConstruction = true;
+            if (QQmlCompiledData *cdata = typeData->compiledData()) {
+                defaultConstruction = false;
+                d->init(ctxtdata, cdata->primitives.at(id), true, script.scopeObject(),
+                        cdata->name, script.d.data()->lineNumber, script.d.data()->columnNumber);
+            }
 
-        if (cdata)
-            cdata->release();
-        if (typeData)
             typeData->release();
+        }
     }
 
     if (defaultConstruction)
diff --git a/src/qml/qml/qqmlincubator.cpp b/src/qml/qml/qqmlincubator.cpp
index 3cd03a9b1b..12a48a2886 100644
--- a/src/qml/qml/qqmlincubator.cpp
+++ b/src/qml/qml/qqmlincubator.cpp
@@ -135,7 +135,7 @@ QQmlIncubationController *QQmlEngine::incubationController() const
 QQmlIncubatorPrivate::QQmlIncubatorPrivate(QQmlIncubator *q, 
                                                            QQmlIncubator::IncubationMode m)
 : q(q), status(QQmlIncubator::Null), mode(m), isAsynchronous(false), progress(Execute),
-  result(0), component(0), vme(this), waitingOnMe(0)
+  result(0), compiledData(0), vme(this), waitingOnMe(0)
 {
 }
 
@@ -147,17 +147,17 @@ void QQmlIncubatorPrivate::clear()
 {
     if (next.isInList()) {
         next.remove();
-        Q_ASSERT(component);
-        QQmlEnginePrivate *enginePriv = QQmlEnginePrivate::get(component->engine);
-        component->release();
-        component = 0;
+        Q_ASSERT(compiledData);
+        QQmlEnginePrivate *enginePriv = QQmlEnginePrivate::get(compiledData->engine);
+        compiledData->release();
+        compiledData = 0;
         enginePriv->incubatorCount--;
         QQmlIncubationController *controller = enginePriv->incubationController;
         if (controller)
             controller->incubatingObjectCountChanged(enginePriv->incubatorCount);
-    } else if (component) {
-        component->release();
-        component = 0;
+    } else if (compiledData) {
+        compiledData->release();
+        compiledData = 0;
     }
     if (!rootContext.isNull()) {
         rootContext->activeVMEData = 0;
@@ -258,14 +258,14 @@ void QQmlIncubationController::incubatingObjectCountChanged(int incubatingObject
 
 void QQmlIncubatorPrivate::incubate(QQmlVME::Interrupt &i)
 {
-    if (!component)
+    if (!compiledData)
         return;
-    QML_MEMORY_SCOPE_URL(component->url);
+    QML_MEMORY_SCOPE_URL(compiledData->url);
 
     typedef QQmlIncubatorPrivate IP;
     QRecursionWatcher<IP, &IP::recursion> watcher(this);
 
-    QQmlEngine *engine = component->engine;
+    QQmlEngine *engine = compiledData->engine;
     QQmlEnginePrivate *enginePriv = QQmlEnginePrivate::get(engine);
 
     bool guardOk = vmeGuard.isOK();
@@ -273,7 +273,7 @@ void QQmlIncubatorPrivate::incubate(QQmlVME::Interrupt &i)
 
     if (!guardOk) {
         QQmlError error;
-        error.setUrl(component->url);
+        error.setUrl(compiledData->url);
         error.setDescription(QQmlComponent::tr("Object destroyed during incubation"));
         errors << error;
         progress = QQmlIncubatorPrivate::Completed;
@@ -539,8 +539,8 @@ void QQmlIncubator::clear()
 
     QQmlEnginePrivate *enginePriv = 0;
     if (s == Loading) {
-        Q_ASSERT(d->component);
-        enginePriv = QQmlEnginePrivate::get(d->component->engine);
+        Q_ASSERT(d->compiledData);
+        enginePriv = QQmlEnginePrivate::get(d->compiledData->engine);
         if (d->result) d->result->deleteLater();
         d->result = 0;
     }
@@ -554,7 +554,7 @@ void QQmlIncubator::clear()
     d->vme.reset();
     d->vmeGuard.clear();
 
-    Q_ASSERT(d->component == 0);
+    Q_ASSERT(d->compiledData == 0);
     Q_ASSERT(d->waitingOnMe == 0);
     Q_ASSERT(d->waitingFor.isEmpty());
     Q_ASSERT(!d->nextWaitingFor.isInList());
@@ -698,7 +698,7 @@ QQmlIncubator::Status QQmlIncubatorPrivate::calculateStatus() const
     else if (result && progress == QQmlIncubatorPrivate::Completed && 
              waitingFor.isEmpty()) 
         return QQmlIncubator::Ready;
-    else if (component) 
+    else if (compiledData)
         return QQmlIncubator::Loading;
     else 
         return QQmlIncubator::Null;
diff --git a/src/qml/qml/qqmlincubator_p.h b/src/qml/qml/qqmlincubator_p.h
index 0dec34a8d5..f5effe3005 100644
--- a/src/qml/qml/qqmlincubator_p.h
+++ b/src/qml/qml/qqmlincubator_p.h
@@ -85,7 +85,7 @@ public:
 
     QQmlGuard<QObject> result;
     QQmlGuardedContextData rootContext;
-    QQmlCompiledData *component;
+    QQmlCompiledData *compiledData;
     QQmlVME vme;
     QQmlVMEGuard vmeGuard;
 
diff --git a/src/qml/qml/qqmltypeloader.cpp b/src/qml/qml/qqmltypeloader.cpp
index a766ee7fef..d550a19874 100644
--- a/src/qml/qml/qqmltypeloader.cpp
+++ b/src/qml/qml/qqmltypeloader.cpp
@@ -98,6 +98,17 @@ DEFINE_BOOL_CONFIG_OPTION(dumpErrors, QML_DUMP_ERRORS);
 
 QT_BEGIN_NAMESPACE
 
+namespace {
+
+    template<typename LockType>
+    struct LockHolder
+    {
+        LockType& lock;
+        LockHolder(LockType *l) : lock(*l) { lock.lock(); }
+        ~LockHolder() { lock.unlock(); }
+    };
+}
+
 // This is a lame object that we need to ensure that slots connected to
 // QNetworkReply get called in the correct thread (the loader thread).  
 // As QQmlDataLoader lives in the main thread, and we can't use
@@ -1204,7 +1215,7 @@ loaded files.
 */
 QQmlTypeLoader::~QQmlTypeLoader()
 {
-    clearCache();
+    clearCache(0, 0);
 }
 
 /*!
@@ -1221,13 +1232,13 @@ This enum defines the options that control the way type data is handled.
 /*!
 Returns a QQmlTypeData for the specified \a url.  The QQmlTypeData may be cached.
 */
-QQmlTypeData *QQmlTypeLoader::get(const QUrl &url, Mode mode)
+QQmlTypeData *QQmlTypeLoader::getType(const QUrl &url, Mode mode)
 {
     Q_ASSERT(!url.isRelative() && 
             (QQmlFile::urlToLocalFileOrQrc(url).isEmpty() ||
              !QDir::isRelativePath(QQmlFile::urlToLocalFileOrQrc(url))));
 
-    lock();
+    LockHolder<QQmlTypeLoader> holder(this);
     
     QQmlTypeData *typeData = m_typeCache.value(url);
 
@@ -1239,8 +1250,6 @@ QQmlTypeData *QQmlTypeLoader::get(const QUrl &url, Mode mode)
 
     typeData->addref();
 
-    unlock();
-
     return typeData;
 }
 
@@ -1250,15 +1259,13 @@ QQmlTypeData will not be cached.
 
 The specified \a options control how the loader handles type data.
 */
-QQmlTypeData *QQmlTypeLoader::get(const QByteArray &data, const QUrl &url, Options options)
+QQmlTypeData *QQmlTypeLoader::getType(const QByteArray &data, const QUrl &url, Options options)
 {
-    lock();
+    LockHolder<QQmlTypeLoader> holder(this);
 
     QQmlTypeData *typeData = new QQmlTypeData(url, options, this);
     QQmlDataLoader::loadWithStaticData(typeData, data);
 
-    unlock();
-
     return typeData;
 }
 
@@ -1271,7 +1278,7 @@ QQmlScriptBlob *QQmlTypeLoader::getScript(const QUrl &url)
             (QQmlFile::urlToLocalFileOrQrc(url).isEmpty() ||
              !QDir::isRelativePath(QQmlFile::urlToLocalFileOrQrc(url))));
 
-    lock();
+    LockHolder<QQmlTypeLoader> holder(this);
 
     QQmlScriptBlob *scriptBlob = m_scriptCache.value(url);
 
@@ -1283,8 +1290,6 @@ QQmlScriptBlob *QQmlTypeLoader::getScript(const QUrl &url)
 
     scriptBlob->addref();
 
-    unlock();
-
     return scriptBlob;
 }
 
@@ -1297,7 +1302,7 @@ QQmlQmldirData *QQmlTypeLoader::getQmldir(const QUrl &url)
             (QQmlFile::urlToLocalFileOrQrc(url).isEmpty() ||
              !QDir::isRelativePath(QQmlFile::urlToLocalFileOrQrc(url))));
 
-    lock();
+    LockHolder<QQmlTypeLoader> holder(this);
 
     QQmlQmldirData *qmldirData = m_qmldirCache.value(url);
 
@@ -1309,8 +1314,6 @@ QQmlQmldirData *QQmlTypeLoader::getQmldir(const QUrl &url)
 
     qmldirData->addref();
 
-    unlock();
-
     return qmldirData;
 }
 
@@ -1562,10 +1565,14 @@ const QQmlDirParser *QQmlTypeLoader::qmlDirParser(const QString &filePath,
 Clears cached information about loaded files, including any type data, scripts
 and qmldir information.
 */
-void QQmlTypeLoader::clearCache()
+void QQmlTypeLoader::clearCache(void (*callback)(void *, QQmlTypeData *), void *arg)
 {
-    for (TypeCache::Iterator iter = m_typeCache.begin(); iter != m_typeCache.end(); ++iter) 
+    for (TypeCache::Iterator iter = m_typeCache.begin(); iter != m_typeCache.end(); ++iter) {
+        if (callback)
+            (*callback)(arg, iter.value());
+
         (*iter)->release();
+    }
     for (ScriptCache::Iterator iter = m_scriptCache.begin(); iter != m_scriptCache.end(); ++iter) 
         (*iter)->release();
     for (QmldirCache::Iterator iter = m_qmldirCache.begin(); iter != m_qmldirCache.end(); ++iter) 
@@ -1580,6 +1587,48 @@ void QQmlTypeLoader::clearCache()
     m_importQmlDirCache.clear();
 }
 
+void QQmlTypeLoader::trimCache(void (*callback)(void *, QQmlTypeData *), void *arg)
+{
+    while (true) {
+        QList<TypeCache::Iterator> unneededTypes;
+        for (TypeCache::Iterator iter = m_typeCache.begin(); iter != m_typeCache.end(); ++iter)  {
+            QQmlTypeData *typeData = iter.value();
+            if (typeData->m_compiledData && typeData->m_compiledData->count() == 1) {
+                // There are no live objects of this type
+                unneededTypes.append(iter);
+            }
+        }
+
+        if (unneededTypes.isEmpty())
+            break;
+
+        while (!unneededTypes.isEmpty()) {
+            TypeCache::Iterator iter = unneededTypes.last();
+            unneededTypes.removeLast();
+
+            if (callback)
+                (*callback)(arg, iter.value());
+
+            m_typeCache.erase(iter);
+            iter.value()->release();
+        }
+    }
+
+    // TODO: release any scripts which are no longer referenced by any types
+}
+
+bool QQmlTypeLoader::isTypeLoaded(const QUrl &url) const
+{
+    LockHolder<QQmlTypeLoader> holder(const_cast<QQmlTypeLoader *>(this));
+    return m_typeCache.contains(url);
+}
+
+bool QQmlTypeLoader::isScriptLoaded(const QUrl &url) const
+{
+    LockHolder<QQmlTypeLoader> holder(const_cast<QQmlTypeLoader *>(this));
+    return m_scriptCache.contains(url);
+}
+
 
 QQmlTypeData::QQmlTypeData(const QUrl &url, QQmlTypeLoader::Options options, 
                                            QQmlTypeLoader *manager)
@@ -1632,9 +1681,6 @@ const QSet<QString> &QQmlTypeData::namespaces() const
 
 QQmlCompiledData *QQmlTypeData::compiledData() const
 {
-    if (m_compiledData) 
-        m_compiledData->addref();
-
     return m_compiledData;
 }
 
@@ -1899,7 +1945,7 @@ void QQmlTypeData::resolveTypes()
             ref.majorVersion = majorVersion;
             ref.minorVersion = minorVersion;
         } else {
-            ref.typeData = typeLoader()->get(QUrl(url));
+            ref.typeData = typeLoader()->getType(QUrl(url));
             addDependency(ref.typeData);
         }
 
diff --git a/src/qml/qml/qqmltypeloader_p.h b/src/qml/qml/qqmltypeloader_p.h
index 66f4fd5081..ab700805c4 100644
--- a/src/qml/qml/qqmltypeloader_p.h
+++ b/src/qml/qml/qqmltypeloader_p.h
@@ -268,9 +268,8 @@ public:
     };
     Q_DECLARE_FLAGS(Options, Option)
 
-    QQmlTypeData *get(const QUrl &url, Mode mode = PreferSynchronous);
-    QQmlTypeData *get(const QByteArray &, const QUrl &url, Options = None);
-    void clearCache();
+    QQmlTypeData *getType(const QUrl &url, Mode mode = PreferSynchronous);
+    QQmlTypeData *getType(const QByteArray &, const QUrl &url, Options = None);
 
     QQmlScriptBlob *getScript(const QUrl &);
     QQmlQmldirData *getQmldir(const QUrl &);
@@ -283,10 +282,44 @@ public:
     bool directoryExists(const QString &path);
     const QQmlDirParser *qmlDirParser(const QString &filePath, const QString &uriHint, QString *outUrl);
 
+    template<typename T>
+    void clearCache(T *o, void (T::*callback)(QQmlTypeData *)) {
+        TypedCallback<T> cb(o, callback);
+        clearCache(&TypedCallback<T>::redirect, &cb);
+    }
+
+    template<typename T>
+    void trimCache(T *o, void (T::*callback)(QQmlTypeData *)) {
+        TypedCallback<T> cb(o, callback);
+        trimCache(&TypedCallback<T>::redirect, &cb);
+    }
+
+    bool isTypeLoaded(const QUrl &url) const;
+    bool isScriptLoaded(const QUrl &url) const;
+
 private:
     void addBundleNoLock(const QString &, const QString &);
     QString bundleIdForQmldir(const QString &qmldir, const QString &uriHint);
 
+    template<typename T>
+    struct TypedCallback
+    {
+        TypedCallback(T *object, void (T::*func)(QQmlTypeData *)) : o(object), mf(func) {}
+
+        static void redirect(void *arg, QQmlTypeData *type)
+        {
+            TypedCallback<T> *self = reinterpret_cast<TypedCallback<T> *>(arg);
+            ((self->o)->*(self->mf))(type);
+        }
+
+    private:
+        T *o;
+        void (T::*mf)(QQmlTypeData *);
+    };
+
+    void clearCache(void (*callback)(void *, QQmlTypeData *), void *);
+    void trimCache(void (*callback)(void *, QQmlTypeData *), void *);
+
     struct DirParser : public QQmlDirParser { QString adjustedUrl; };
 
     typedef QHash<QUrl, QQmlTypeData *> TypeCache;
@@ -332,7 +365,12 @@ public:
         QQmlScriptBlob *script;
     };
 
+private:
+    friend class QQmlTypeLoader;
+
     QQmlTypeData(const QUrl &, QQmlTypeLoader::Options, QQmlTypeLoader *);
+
+public:
     ~QQmlTypeData();
 
     QQmlTypeLoader *typeLoader() const;
@@ -397,8 +435,12 @@ private:
 // only created and destroyed in the main thread :)
 class Q_AUTOTEST_EXPORT QQmlScriptData : public QQmlCleanup, public QQmlRefCount
 {
-public:
+private:
+    friend class QQmlTypeLoader;
+
     QQmlScriptData();
+
+public:
     ~QQmlScriptData();
 
     QUrl url;
@@ -425,8 +467,12 @@ private:
 
 class Q_AUTOTEST_EXPORT QQmlScriptBlob : public QQmlDataBlob
 {
-public:
+private:
+    friend class QQmlTypeLoader;
+
     QQmlScriptBlob(const QUrl &, QQmlTypeLoader *);
+
+public:
     ~QQmlScriptBlob();
 
     struct ScriptReference
@@ -463,9 +509,12 @@ private:
 
 class Q_AUTOTEST_EXPORT QQmlQmldirData : public QQmlDataBlob
 {
-public:
+private:
+    friend class QQmlTypeLoader;
+
     QQmlQmldirData(const QUrl &);
 
+public:
     const QQmlDirComponents &dirComponents() const;
 
 protected:
@@ -473,7 +522,6 @@ protected:
 
 private:
     QQmlDirComponents m_components;
-
 };
 
 QQmlDataBlob::Data::Data()
diff --git a/src/qml/qml/qqmlvme.cpp b/src/qml/qml/qqmlvme.cpp
index 852a682630..ba0f202bcc 100644
--- a/src/qml/qml/qqmlvme.cpp
+++ b/src/qml/qml/qqmlvme.cpp
@@ -133,11 +133,11 @@ bool QQmlVME::initDeferred(QObject *object)
 {
     QQmlData *data = QQmlData::get(object);
 
-    if (!data || !data->context || !data->deferredComponent)
+    if (!data || !data->context || !data->compiledData)
         return false;
 
     QQmlContextData *ctxt = data->context;
-    QQmlCompiledData *comp = data->deferredComponent;
+    QQmlCompiledData *comp = data->compiledData;
     int start = data->deferredIdx;
 
     State initState;
@@ -444,7 +444,7 @@ QObject *QQmlVME::run(QList<QQmlError> *errors,
                 CTXT->setIdPropertyData(COMP->contextCaches.at(instr.contextCache));
             if (instr.compiledBinding != -1) {
                 const char *v4data = DATAS.at(instr.compiledBinding).constData();
-                CTXT->v4bindings = new QV4Bindings(v4data, CTXT, COMP);
+                CTXT->v4bindings = new QV4Bindings(v4data, CTXT);
             }
             if (states.count() == 1) {
                 rootContext = CTXT;
@@ -515,6 +515,15 @@ QObject *QQmlVME::run(QList<QQmlError> *errors,
             QQmlData *ddata = QQmlData::get(o);
             Q_ASSERT(ddata);
 
+            if (states.count() == 1) {
+                // Keep a reference to the compiled data we rely on.
+                // Only the top-level component instance needs to add a reference - higher-level
+                // components add a reference to the components they depend on, so an instance
+                // of the top-level component keeps them all referenced.
+                ddata->compiledData = states[0].compiledData;
+                ddata->compiledData->addref();
+            }
+
             if (instr.isRoot) {
                 if (ddata->context) {
                     Q_ASSERT(ddata->context != CTXT);
@@ -563,6 +572,12 @@ QObject *QQmlVME::run(QList<QQmlError> *errors,
                 VME_EXCEPTION(tr("Unable to create object of type %1").arg(type.type->elementName()),
                               instr.line);
 
+            if (states.count() == 1) {
+                // Keep a reference to the compiled data we rely on
+                ddata->compiledData = states[0].compiledData;
+                ddata->compiledData->addref();
+            }
+
             if (instr.isRoot) {
                 if (ddata->context) {
                     Q_ASSERT(ddata->context != CTXT);
@@ -649,6 +664,12 @@ QObject *QQmlVME::run(QList<QQmlError> *errors,
 
             CTXT->addObject(qcomp);
 
+            if (states.count() == 1) {
+                // Keep a reference to the compiled data we rely on
+                ddata->compiledData = states[0].compiledData;
+                ddata->compiledData->addref();
+            }
+
             if (instr.isRoot)
                 ddata->ownContext = true;
 
@@ -673,7 +694,7 @@ QObject *QQmlVME::run(QList<QQmlError> *errors,
             const QQmlVMEMetaData *data = 
                 (const QQmlVMEMetaData *)DATAS.at(instr.aliasData).constData();
 
-            (void)new QQmlVMEMetaObject(target, &mo, data, COMP);
+            (void)new QQmlVMEMetaObject(target, &mo, data);
 
             if (instr.propertyCache != -1) {
                 QQmlData *ddata = QQmlData::get(target, true);
@@ -1000,11 +1021,11 @@ QObject *QQmlVME::run(QList<QQmlError> *errors,
         QML_BEGIN_INSTR(Defer)
             if (instr.deferCount) {
                 QObject *target = objects.top();
-                QQmlData *data = 
-                    QQmlData::get(target, true);
-                COMP->addref();
-                data->deferredComponent = COMP;
+                QQmlData *data = QQmlData::get(target, true);
+                data->compiledData = COMP;
+                data->compiledData->addref(); // Keep this data referenced until we're initialized
                 data->deferredIdx = INSTRUCTIONSTREAM - COMP->bytecode.constData();
+                Q_ASSERT(data->deferredIdx != 0);
                 INSTRUCTIONSTREAM += instr.deferCount;
             }
         QML_END_INSTR(Defer)
diff --git a/src/qml/qml/qqmlvmemetaobject.cpp b/src/qml/qml/qqmlvmemetaobject.cpp
index 01a4737e2f..4d531b392c 100644
--- a/src/qml/qml/qqmlvmemetaobject.cpp
+++ b/src/qml/qml/qqmlvmemetaobject.cpp
@@ -480,17 +480,12 @@ void QQmlVMEMetaObjectEndpoint::tryConnect()
     }
 }
 
-QQmlVMEMetaObject::QQmlVMEMetaObject(QObject *obj,
-                                                     const QMetaObject *other, 
-                                                     const QQmlVMEMetaData *meta,
-                                                     QQmlCompiledData *cdata)
-: QV8GCCallback::Node(GcPrologueCallback), object(obj), compiledData(cdata),
+QQmlVMEMetaObject::QQmlVMEMetaObject(QObject *obj, const QMetaObject *other, const QQmlVMEMetaData *meta)
+: QV8GCCallback::Node(GcPrologueCallback), object(obj),
   ctxt(QQmlData::get(obj, true)->outerContext), metaData(meta), data(0),
   aliasEndpoints(0), firstVarPropertyIndex(-1), varPropertiesInitialized(false),
   interceptors(0), v8methods(0), parent(0)
 {
-    compiledData->addref();
-
     *static_cast<QMetaObject *>(this) = *other;
     this->d.superdata = obj->metaObject();
 
@@ -523,7 +518,6 @@ QQmlVMEMetaObject::QQmlVMEMetaObject(QObject *obj,
 
 QQmlVMEMetaObject::~QQmlVMEMetaObject()
 {
-    compiledData->release();
     delete parent;
     delete [] data;
     delete [] aliasEndpoints;
diff --git a/src/qml/qml/qqmlvmemetaobject_p.h b/src/qml/qml/qqmlvmemetaobject_p.h
index 53fe34d415..1f44c63a47 100644
--- a/src/qml/qml/qqmlvmemetaobject_p.h
+++ b/src/qml/qml/qqmlvmemetaobject_p.h
@@ -156,8 +156,7 @@ class Q_AUTOTEST_EXPORT QQmlVMEMetaObject : public QAbstractDynamicMetaObject,
                                                     public QV8GCCallback::Node
 {
 public:
-    QQmlVMEMetaObject(QObject *obj, const QMetaObject *other, const QQmlVMEMetaData *data,
-                     QQmlCompiledData *compiledData);
+    QQmlVMEMetaObject(QObject *obj, const QMetaObject *other, const QQmlVMEMetaData *data);
     ~QQmlVMEMetaObject();
 
     bool aliasTarget(int index, QObject **target, int *coreIndex, int *valueTypeIndex) const;
@@ -178,7 +177,6 @@ private:
     friend class QQmlVMEVariantQObjectPtr;
 
     QObject *object;
-    QQmlCompiledData *compiledData;
     QQmlGuardedContextData ctxt;
 
     const QQmlVMEMetaData *metaData;
diff --git a/src/qml/qml/v4/qv4bindings.cpp b/src/qml/qml/v4/qv4bindings.cpp
index 2c60883207..6ab1e00b5c 100644
--- a/src/qml/qml/v4/qv4bindings.cpp
+++ b/src/qml/qml/v4/qv4bindings.cpp
@@ -251,15 +251,10 @@ void Register::init(Type type)
 
 } // end of anonymous namespace
 
-QV4Bindings::QV4Bindings(const char *programData, 
-                                               QQmlContextData *context, 
-                                               QQmlRefCount *ref)
-: subscriptions(0), program(0), dataRef(0), bindings(0)
+QV4Bindings::QV4Bindings(const char *programData, QQmlContextData *context)
+: subscriptions(0), program(0), bindings(0)
 {
     program = (QV4Program *)programData;
-    dataRef = ref;
-    if (dataRef) dataRef->addref();
-
     if (program) {
         subscriptions = new Subscription[program->subscriptions];
         bindings = new Binding[program->bindings];
@@ -270,9 +265,8 @@ QV4Bindings::QV4Bindings(const char *programData,
 
 QV4Bindings::~QV4Bindings()
 {
-    delete [] bindings;
+    delete [] bindings; bindings = 0;
     delete [] subscriptions; subscriptions = 0;
-    if (dataRef) dataRef->release();
 }
 
 QQmlAbstractBinding *QV4Bindings::configBinding(int index, QObject *target, 
@@ -727,7 +721,7 @@ void **QV4Bindings::getDecodeInstrTable()
 {
     static void **decode_instr;
     if (!decode_instr) {
-        QV4Bindings *dummy = new QV4Bindings(0, 0, 0);
+        QV4Bindings *dummy = new QV4Bindings(0, 0);
         quint32 executedBlocks = 0;
         dummy->run(0, executedBlocks, 0, 0, 0, 0, 
                    QQmlPropertyPrivate::BypassInterceptor, 
diff --git a/src/qml/qml/v4/qv4bindings_p.h b/src/qml/qml/v4/qv4bindings_p.h
index cb483d1f95..be58e02358 100644
--- a/src/qml/qml/v4/qv4bindings_p.h
+++ b/src/qml/qml/v4/qv4bindings_p.h
@@ -68,8 +68,7 @@ class QV4Bindings : public QQmlAbstractExpression,
 {
     Q_DECLARE_TR_FUNCTIONS(QV4Bindings)
 public:
-    QV4Bindings(const char *program, QQmlContextData *context,
-                           QQmlRefCount *);
+    QV4Bindings(const char *program, QQmlContextData *context);
     virtual ~QV4Bindings();
 
     QQmlAbstractBinding *configBinding(int index, QObject *target, 
@@ -131,7 +130,6 @@ private:
     void run(Binding *, QQmlPropertyPrivate::WriteFlags flags);
 
     QV4Program *program;
-    QQmlRefCount *dataRef;
     Binding *bindings;
 
     void init();
diff --git a/src/qml/qml/v8/qv8bindings.cpp b/src/qml/qml/v8/qv8bindings.cpp
index 31780a3d16..c92b87ac6c 100644
--- a/src/qml/qml/v8/qv8bindings.cpp
+++ b/src/qml/qml/v8/qv8bindings.cpp
@@ -199,8 +199,6 @@ QV8Bindings::QV8Bindings(QQmlCompiledData::V8Program *program,
                          QQmlContextData *context)
 : program(program), bindings(0), refCount(1)
 {
-    program->cdata->addref();
-
     QV8Engine *engine = QQmlEnginePrivate::getV8Engine(context->engine);
 
     if (program->bindings.IsEmpty()) {
@@ -247,7 +245,6 @@ QV8Bindings::QV8Bindings(QQmlCompiledData::V8Program *program,
 
 QV8Bindings::~QV8Bindings()
 {
-    program->cdata->release();
     program = 0;
 
     delete [] bindings;
diff --git a/tests/auto/qml/qqmlengine/data/EmptyAggregateEmptyComponent.qml b/tests/auto/qml/qqmlengine/data/EmptyAggregateEmptyComponent.qml
new file mode 100644
index 0000000000..76a0e32335
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/EmptyAggregateEmptyComponent.qml
@@ -0,0 +1,6 @@
+import QtQuick 2.0
+
+Item {
+    EmptyComponent {
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/EmptyAggregateVMEComponent.qml b/tests/auto/qml/qqmlengine/data/EmptyAggregateVMEComponent.qml
new file mode 100644
index 0000000000..7e6821ee48
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/EmptyAggregateVMEComponent.qml
@@ -0,0 +1,6 @@
+import QtQuick 2.0
+
+Item {
+    VMEComponent {
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/EmptyComponent.qml b/tests/auto/qml/qqmlengine/data/EmptyComponent.qml
new file mode 100644
index 0000000000..459c82afbb
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/EmptyComponent.qml
@@ -0,0 +1,4 @@
+import QtQuick 2.0
+
+Item {
+}
diff --git a/tests/auto/qml/qqmlengine/data/EmptyExtendEmptyComponent.qml b/tests/auto/qml/qqmlengine/data/EmptyExtendEmptyComponent.qml
new file mode 100644
index 0000000000..728b8e7798
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/EmptyExtendEmptyComponent.qml
@@ -0,0 +1,4 @@
+import QtQuick 2.0
+
+EmptyComponent {
+}
diff --git a/tests/auto/qml/qqmlengine/data/EmptyExtendVMEComponent.qml b/tests/auto/qml/qqmlengine/data/EmptyExtendVMEComponent.qml
new file mode 100644
index 0000000000..88efc731a0
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/EmptyExtendVMEComponent.qml
@@ -0,0 +1,4 @@
+import QtQuick 2.0
+
+VMEComponent {
+}
diff --git a/tests/auto/qml/qqmlengine/data/EmptyPropertyEmptyComponent.qml b/tests/auto/qml/qqmlengine/data/EmptyPropertyEmptyComponent.qml
new file mode 100644
index 0000000000..293a8e713e
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/EmptyPropertyEmptyComponent.qml
@@ -0,0 +1,5 @@
+import QtQuick 2.0
+
+Item {
+    property EmptyComponent p: EmptyComponent {}
+}
diff --git a/tests/auto/qml/qqmlengine/data/EmptyPropertyVMEComponent.qml b/tests/auto/qml/qqmlengine/data/EmptyPropertyVMEComponent.qml
new file mode 100644
index 0000000000..8444edc829
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/EmptyPropertyVMEComponent.qml
@@ -0,0 +1,5 @@
+import QtQuick 2.0
+
+Item {
+    property VMEComponent p: VMEComponent {}
+}
diff --git a/tests/auto/qml/qqmlengine/data/NestedEmptyComponent.qml b/tests/auto/qml/qqmlengine/data/NestedEmptyComponent.qml
new file mode 100644
index 0000000000..728b8e7798
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/NestedEmptyComponent.qml
@@ -0,0 +1,4 @@
+import QtQuick 2.0
+
+EmptyComponent {
+}
diff --git a/tests/auto/qml/qqmlengine/data/NestedVMEComponent.qml b/tests/auto/qml/qqmlengine/data/NestedVMEComponent.qml
new file mode 100644
index 0000000000..fd4f15482c
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/NestedVMEComponent.qml
@@ -0,0 +1,5 @@
+import QtQuick 2.0
+
+VMEComponent {
+    property real pi: 3.1415927
+}
diff --git a/tests/auto/qml/qqmlengine/data/ScriptComponent.qml b/tests/auto/qml/qqmlengine/data/ScriptComponent.qml
new file mode 100644
index 0000000000..3fb9a10e85
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/ScriptComponent.qml
@@ -0,0 +1,6 @@
+import QtQuick 2.0
+import "script.js" as JS
+
+VMEExtendVMEComponent {
+    function getSomething() { return JS.getSomething() }
+}
diff --git a/tests/auto/qml/qqmlengine/data/TopLevelComponent.qml b/tests/auto/qml/qqmlengine/data/TopLevelComponent.qml
new file mode 100644
index 0000000000..dea8a9ce2e
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/TopLevelComponent.qml
@@ -0,0 +1,6 @@
+import QtQuick 2.0
+
+Component {
+    VMEExtendVMEComponent {
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/VMEAggregateEmptyComponent.qml b/tests/auto/qml/qqmlengine/data/VMEAggregateEmptyComponent.qml
new file mode 100644
index 0000000000..a34a036471
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/VMEAggregateEmptyComponent.qml
@@ -0,0 +1,8 @@
+import QtQuick 2.0
+
+Item {
+    property string bar: 'baz'
+
+    EmptyComponent {
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/VMEAggregateVMEComponent.qml b/tests/auto/qml/qqmlengine/data/VMEAggregateVMEComponent.qml
new file mode 100644
index 0000000000..4bacdf8042
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/VMEAggregateVMEComponent.qml
@@ -0,0 +1,8 @@
+import QtQuick 2.0
+
+Item {
+    property string foo: 'bar'
+
+    VMEComponent {
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/VMEComponent.qml b/tests/auto/qml/qqmlengine/data/VMEComponent.qml
new file mode 100644
index 0000000000..0a43a08711
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/VMEComponent.qml
@@ -0,0 +1,5 @@
+import QtQuick 2.0
+
+Item {
+    property string foo: 'bar'
+}
diff --git a/tests/auto/qml/qqmlengine/data/VMEExtendEmptyComponent.qml b/tests/auto/qml/qqmlengine/data/VMEExtendEmptyComponent.qml
new file mode 100644
index 0000000000..df81f6bb88
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/VMEExtendEmptyComponent.qml
@@ -0,0 +1,5 @@
+import QtQuick 2.0
+
+EmptyComponent {
+    property string bar: 'baz'
+}
diff --git a/tests/auto/qml/qqmlengine/data/VMEExtendVMEComponent.qml b/tests/auto/qml/qqmlengine/data/VMEExtendVMEComponent.qml
new file mode 100644
index 0000000000..bf7a2ecdc2
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/VMEExtendVMEComponent.qml
@@ -0,0 +1,5 @@
+import QtQuick 2.0
+
+VMEComponent {
+    property string bar: 'baz'
+}
diff --git a/tests/auto/qml/qqmlengine/data/VMEPropertyEmptyComponent.qml b/tests/auto/qml/qqmlengine/data/VMEPropertyEmptyComponent.qml
new file mode 100644
index 0000000000..4ead1e0088
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/VMEPropertyEmptyComponent.qml
@@ -0,0 +1,7 @@
+import QtQuick 2.0
+
+Item {
+    property string foo: 'bar'
+
+    property EmptyComponent p: EmptyComponent {}
+}
diff --git a/tests/auto/qml/qqmlengine/data/VMEPropertyVMEComponent.qml b/tests/auto/qml/qqmlengine/data/VMEPropertyVMEComponent.qml
new file mode 100644
index 0000000000..88867f29fc
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/VMEPropertyVMEComponent.qml
@@ -0,0 +1,7 @@
+import QtQuick 2.0
+
+Item {
+    property string foo: 'bar'
+
+    property VMEComponent p: VMEComponent {}
+}
diff --git a/tests/auto/qml/qqmlengine/data/VMETransientEmptyComponent.qml b/tests/auto/qml/qqmlengine/data/VMETransientEmptyComponent.qml
new file mode 100644
index 0000000000..487025f67f
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/VMETransientEmptyComponent.qml
@@ -0,0 +1,15 @@
+import QtQuick 2.0
+
+Item {
+    property var p: null
+
+    Component.onCompleted: {
+        var c = Qt.createComponent('EmptyComponent.qml')
+        p = c.createObject()
+        c.destroy()
+    }
+
+    Component.onDestruction: {
+        p.destroy()
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/VMETransientVMEComponent.qml b/tests/auto/qml/qqmlengine/data/VMETransientVMEComponent.qml
new file mode 100644
index 0000000000..8f29b53ca5
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/VMETransientVMEComponent.qml
@@ -0,0 +1,15 @@
+import QtQuick 2.0
+
+Item {
+    property var p: null
+
+    Component.onCompleted: {
+        var c = Qt.createComponent('VMEComponent.qml')
+        p = c.createObject()
+        c.destroy()
+    }
+
+    Component.onDestruction: {
+        p.destroy()
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/script.js b/tests/auto/qml/qqmlengine/data/script.js
new file mode 100644
index 0000000000..616de3ddd7
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/script.js
@@ -0,0 +1 @@
+function getSomething() { return 'https://example.org/' }
diff --git a/tests/auto/qml/qqmlengine/data/testEmptyAggregateEmptyComponent.1.qml b/tests/auto/qml/qqmlengine/data/testEmptyAggregateEmptyComponent.1.qml
new file mode 100644
index 0000000000..812242f146
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testEmptyAggregateEmptyComponent.1.qml
@@ -0,0 +1,38 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateEmptyComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('EmptyAggregateEmptyComponent.qml')) return reportError('Aggregate component already loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('EmptyAggregateEmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateEmptyComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('EmptyAggregateEmptyComponent.qml')) return reportError('Aggregate component not loaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateEmptyComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('EmptyAggregateEmptyComponent.qml')) return reportError('Aggregate component already unloaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateEmptyComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('EmptyAggregateEmptyComponent.qml')) return reportError('Aggregate component not unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testEmptyAggregateEmptyComponent.2.qml b/tests/auto/qml/qqmlengine/data/testEmptyAggregateEmptyComponent.2.qml
new file mode 100644
index 0000000000..a171ee6b28
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testEmptyAggregateEmptyComponent.2.qml
@@ -0,0 +1,40 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateEmptyComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('EmptyAggregateEmptyComponent.qml')) return reportError('Aggregate component already loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('EmptyAggregateEmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateEmptyComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('EmptyAggregateEmptyComponent.qml')) return reportError('Aggregate component not loaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateEmptyComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('EmptyAggregateEmptyComponent.qml')) return reportError('Aggregate component already unloaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+        if (!obj) return reportError('Invalid object 3')
+        if (obj.x == undefined) return reportError('Invalid object 4')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateEmptyComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('EmptyAggregateEmptyComponent.qml')) return reportError('Aggregate component not unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testEmptyAggregateVMEComponent.1.qml b/tests/auto/qml/qqmlengine/data/testEmptyAggregateVMEComponent.1.qml
new file mode 100644
index 0000000000..de40284452
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testEmptyAggregateVMEComponent.1.qml
@@ -0,0 +1,39 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateVMEComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('EmptyExtendVMEComponent.qml')) return reportError('Aggregate component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('EmptyAggregateVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateVMEComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('EmptyAggregateVMEComponent.qml')) return reportError('Aggregate component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+        if (obj.children[0].foo != 'bar') return reportError('Invalid object 3')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateVMEComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('EmptyAggregateVMEComponent.qml')) return reportError('Aggregate component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateVMEComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('EmptyAggregateVMEComponent.qml')) return reportError('Aggregate component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testEmptyAggregateVMEComponent.2.qml b/tests/auto/qml/qqmlengine/data/testEmptyAggregateVMEComponent.2.qml
new file mode 100644
index 0000000000..4939087b31
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testEmptyAggregateVMEComponent.2.qml
@@ -0,0 +1,42 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateVMEComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('EmptyExtendVMEComponent.qml')) return reportError('Aggregate component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('EmptyAggregateVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateVMEComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('EmptyAggregateVMEComponent.qml')) return reportError('Aggregate component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+        if (obj.children[0].foo != 'bar') return reportError('Invalid object 3')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateVMEComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('EmptyAggregateVMEComponent.qml')) return reportError('Aggregate component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+        if (!obj) return reportError('Invalid object 4')
+        if (obj.x == undefined) return reportError('Invalid object 5')
+        if (obj.children[0].foo != 'bar') return reportError('Invalid object 6')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyAggregateVMEComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('EmptyAggregateVMEComponent.qml')) return reportError('Aggregate component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testEmptyComponent.1.qml b/tests/auto/qml/qqmlengine/data/testEmptyComponent.1.qml
new file mode 100644
index 0000000000..5cee0341fe
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testEmptyComponent.1.qml
@@ -0,0 +1,34 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('EmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testEmptyComponent.2.qml b/tests/auto/qml/qqmlengine/data/testEmptyComponent.2.qml
new file mode 100644
index 0000000000..2a13822fab
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testEmptyComponent.2.qml
@@ -0,0 +1,36 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('EmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+        if (!obj) return reportError('Invalid object 3')
+        if (obj.x == undefined) return reportError('Invalid object 4')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testEmptyExtendEmptyComponent.1.qml b/tests/auto/qml/qqmlengine/data/testEmptyExtendEmptyComponent.1.qml
new file mode 100644
index 0000000000..2f238175fa
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testEmptyExtendEmptyComponent.1.qml
@@ -0,0 +1,38 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendEmptyComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('EmptyExtendEmptyComponent.qml')) return reportError('Extend component already loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('EmptyExtendEmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendEmptyComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('EmptyExtendEmptyComponent.qml')) return reportError('Extend component not loaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendEmptyComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('EmptyExtendEmptyComponent.qml')) return reportError('Extend component already unloaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendEmptyComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('EmptyExtendEmptyComponent.qml')) return reportError('Extend component not unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testEmptyExtendEmptyComponent.2.qml b/tests/auto/qml/qqmlengine/data/testEmptyExtendEmptyComponent.2.qml
new file mode 100644
index 0000000000..d36e95fec3
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testEmptyExtendEmptyComponent.2.qml
@@ -0,0 +1,40 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendEmptyComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('EmptyExtendEmptyComponent.qml')) return reportError('Extend component already loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('EmptyExtendEmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendEmptyComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('EmptyExtendEmptyComponent.qml')) return reportError('Extend component not loaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendEmptyComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('EmptyExtendEmptyComponent.qml')) return reportError('Extend component already unloaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+        if (!obj) return reportError('Invalid object 3')
+        if (obj.x == undefined) return reportError('Invalid object 4')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendEmptyComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('EmptyExtendEmptyComponent.qml')) return reportError('Extend component not unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testEmptyExtendVMEComponent.1.qml b/tests/auto/qml/qqmlengine/data/testEmptyExtendVMEComponent.1.qml
new file mode 100644
index 0000000000..53dd5a17e9
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testEmptyExtendVMEComponent.1.qml
@@ -0,0 +1,39 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendVMEComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('EmptyExtendVMEComponent.qml')) return reportError('Extend component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('EmptyExtendVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendVMEComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('EmptyExtendVMEComponent.qml')) return reportError('Extend component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+        if (obj.foo != 'bar') return reportError('Invalid object 3')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendVMEComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('EmptyExtendVMEComponent.qml')) return reportError('Extend component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendVMEComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('EmptyExtendVMEComponent.qml')) return reportError('Extend component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testEmptyExtendVMEComponent.2.qml b/tests/auto/qml/qqmlengine/data/testEmptyExtendVMEComponent.2.qml
new file mode 100644
index 0000000000..e5cd7d60de
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testEmptyExtendVMEComponent.2.qml
@@ -0,0 +1,42 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendVMEComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('EmptyExtendVMEComponent.qml')) return reportError('Extend component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('EmptyExtendVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendVMEComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('EmptyExtendVMEComponent.qml')) return reportError('Extend component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+        if (obj.foo != 'bar') return reportError('Invalid object 3')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendVMEComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('EmptyExtendVMEComponent.qml')) return reportError('Extend component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+        if (!obj) return reportError('Invalid object 4')
+        if (obj.x == undefined) return reportError('Invalid object 5')
+        if (obj.foo != 'bar') return reportError('Invalid object 6')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyExtendVMEComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('EmptyExtendVMEComponent.qml')) return reportError('Extend component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testEmptyPropertyEmptyComponent.1.qml b/tests/auto/qml/qqmlengine/data/testEmptyPropertyEmptyComponent.1.qml
new file mode 100644
index 0000000000..d98aef2932
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testEmptyPropertyEmptyComponent.1.qml
@@ -0,0 +1,40 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyEmptyComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('EmptyPropertyEmptyComponent.qml')) return reportError('Property component already loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('EmptyPropertyEmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyEmptyComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('EmptyPropertyEmptyComponent.qml')) return reportError('Property component not loaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+        if (obj.p == undefined) return reportError('Invalid object 3')
+        if (obj.p.x == undefined) return reportError('Invalid object 4')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyEmptyComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('EmptyPropertyEmptyComponent.qml')) return reportError('Property component already unloaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyEmptyComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('EmptyPropertyEmptyComponent.qml')) return reportError('Property component not unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testEmptyPropertyEmptyComponent.2.qml b/tests/auto/qml/qqmlengine/data/testEmptyPropertyEmptyComponent.2.qml
new file mode 100644
index 0000000000..7f438aa995
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testEmptyPropertyEmptyComponent.2.qml
@@ -0,0 +1,44 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyEmptyComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('EmptyPropertyEmptyComponent.qml')) return reportError('Property component already loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('EmptyPropertyEmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyEmptyComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('EmptyPropertyEmptyComponent.qml')) return reportError('Property component not loaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+        if (obj.p == undefined) return reportError('Invalid object 3')
+        if (obj.p.x == undefined) return reportError('Invalid object 4')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyEmptyComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('EmptyPropertyEmptyComponent.qml')) return reportError('Property component already unloaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+        if (!obj) return reportError('Invalid object 5')
+        if (obj.x == undefined) return reportError('Invalid object 6')
+        if (obj.p == undefined) return reportError('Invalid object 7')
+        if (obj.p.x == undefined) return reportError('Invalid object 8')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyEmptyComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('EmptyPropertyEmptyComponent.qml')) return reportError('Property component not unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testEmptyPropertyVMEComponent.1.qml b/tests/auto/qml/qqmlengine/data/testEmptyPropertyVMEComponent.1.qml
new file mode 100644
index 0000000000..83d6226e83
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testEmptyPropertyVMEComponent.1.qml
@@ -0,0 +1,40 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyVMEComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('EmptyPropertyVMEComponent.qml')) return reportError('Property component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('EmptyPropertyVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyVMEComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('EmptyPropertyVMEComponent.qml')) return reportError('Property component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+        if (obj.p == undefined) return reportError('Invalid object 3')
+        if (obj.p.foo != 'bar') return reportError('Invalid object 4')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyVMEComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('EmptyPropertyVMEComponent.qml')) return reportError('Property component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyVMEComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('EmptyPropertyVMEComponent.qml')) return reportError('Property component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testEmptyPropertyVMEComponent.2.qml b/tests/auto/qml/qqmlengine/data/testEmptyPropertyVMEComponent.2.qml
new file mode 100644
index 0000000000..98dfb7241b
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testEmptyPropertyVMEComponent.2.qml
@@ -0,0 +1,44 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyVMEComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('EmptyPropertyVMEComponent.qml')) return reportError('Property component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('EmptyPropertyVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyVMEComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('EmptyPropertyVMEComponent.qml')) return reportError('Property component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+        if (obj.p == undefined) return reportError('Invalid object 3')
+        if (obj.p.foo != 'bar') return reportError('Invalid object 4')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyVMEComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('EmptyPropertyVMEComponent.qml')) return reportError('Property component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+        if (!obj) return reportError('Invalid object 5')
+        if (obj.x == undefined) return reportError('Invalid object 6')
+        if (obj.p == undefined) return reportError('Invalid object 7')
+        if (obj.p.foo != 'bar') return reportError('Invalid object 8')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testEmptyPropertyVMEComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('EmptyPropertyVMEComponent.qml')) return reportError('Property component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testIncubatedComponent.qml b/tests/auto/qml/qqmlengine/data/testIncubatedComponent.qml
new file mode 100644
index 0000000000..50af9c4f16
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testIncubatedComponent.qml
@@ -0,0 +1,51 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testIncubatedComponent.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var c = Qt.createComponent('VMEExtendVMEComponent.qml')
+        var i = c.incubateObject(null, {}, Qt.Asynchronous)
+
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testIncubatedComponent.qml')) return reportError('Test component unloaded 1')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        c.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testIncubatedComponent.qml')) return reportError('Test component unloaded 2')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+
+        i.onStatusChanged = function(status) {
+            if (status != Component.Ready) return;
+            if (i.object == null) return reportError('Extend component not created')
+            if (i.object.foo != 'bar') return reportError('Invalid object')
+            if (i.object.bar != 'baz') return reportError('Invalid object 2')
+
+            componentCache.trim()
+            if (!componentCache.isTypeLoaded('testIncubatedComponent.qml')) return reportError('Test component unloaded 3')
+            if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component already unloaded 2')
+            if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded 2')
+
+            i.object.destroy()
+            componentCache.trim()
+            if (!componentCache.isTypeLoaded('testIncubatedComponent.qml')) return reportError('Test component unloaded 4')
+            if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not unloaded')
+            if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+            success = true
+        }
+
+        componentCache.beginIncubation()
+        componentCache.waitForIncubation();
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testLoaderComponent.qml b/tests/auto/qml/qqmlengine/data/testLoaderComponent.qml
new file mode 100644
index 0000000000..a04ca41c26
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testLoaderComponent.qml
@@ -0,0 +1,62 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testLoaderComponent.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        loader.source = 'VMEExtendVMEComponent.qml'
+    }
+
+    Loader {
+        id: loader
+
+        property bool previouslyLoaded: false
+        onLoaded: {
+            if (!previouslyLoaded) {
+                componentCache.trim()
+                if (!componentCache.isTypeLoaded('testLoaderComponent.qml')) return reportError('Test component not loaded 2')
+                if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component already unloaded')
+                if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+
+                if (!item) return reportError('Invalid item')
+                if (item.foo != 'bar') return reportError('Invalid item 2')
+                if (item.bar != 'baz') return reportError('Invalid item 3')
+
+                loader.source = ''
+                componentCache.trim()
+                if (!componentCache.isTypeLoaded('testLoaderComponent.qml')) return reportError('Test component not loaded 3')
+                if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not unloaded')
+                if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+                if (item) return reportError('Item not invalidated')
+
+                previouslyLoaded = true
+                loader.source = 'VMEExtendVMEComponent.qml'
+            } else {
+                componentCache.trim()
+                if (!componentCache.isTypeLoaded('testLoaderComponent.qml')) return reportError('Test component not loaded 4')
+                if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not reloaded')
+                if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not reloaded')
+
+                if (!item) return reportError('Invalid item 4')
+                if (item.foo != 'bar') return reportError('Invalid item 5')
+                if (item.bar != 'baz') return reportError('Invalid item 6')
+
+                loader.source = ''
+                componentCache.trim()
+                if (!componentCache.isTypeLoaded('testLoaderComponent.qml')) return reportError('Test component not loaded 5')
+                if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not unloaded 2')
+                if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded 2')
+                if (item) return reportError('Item not invalidated 2')
+
+                success = true
+            }
+        }
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testReloadComponent.qml b/tests/auto/qml/qqmlengine/data/testReloadComponent.qml
new file mode 100644
index 0000000000..74442108cd
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testReloadComponent.qml
@@ -0,0 +1,52 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testReloadComponent.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('VMEExtendVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testReloadComponent.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.foo != 'bar') return reportError('Invalid object 2')
+        if (obj.bar != 'baz') return reportError('Invalid object 3')
+
+        obj.destroy()
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testReloadComponent.qml')) return reportError('Test component not loaded 3')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        comp = Qt.createComponent('VMEExtendVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testReloadComponent.qml')) return reportError('Test component not loaded 4')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not reloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not reloaded')
+
+        obj = comp.createObject()
+        if (!obj) return reportError('Invalid object 4')
+        if (obj.foo != 'bar') return reportError('Invalid object 5')
+        if (obj.bar != 'baz') return reportError('Invalid object 6')
+
+        obj.destroy()
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testReloadComponent.qml')) return reportError('Test component not loaded 5')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not unloaded 2')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded 2')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testScriptComponent.qml b/tests/auto/qml/qqmlengine/data/testScriptComponent.qml
new file mode 100644
index 0000000000..b33eb48461
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testScriptComponent.qml
@@ -0,0 +1,43 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testScriptComponent.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('ScriptComponent.qml')) return reportError('Script component already loaded')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+        if (componentCache.isScriptLoaded('script.js')) return reportError('Script file already loaded')
+
+        var comp = Qt.createComponent('ScriptComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testScriptComponent.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('ScriptComponent.qml')) return reportError('Script component not loaded')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+        if (!componentCache.isScriptLoaded('script.js')) return reportError('Script file not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.foo != 'bar') return reportError('Invalid object 2')
+        if (obj.bar != 'baz') return reportError('Invalid object 3')
+        if (obj.getSomething() != 'https://example.org/') return reportError('Invalid object 4')
+
+        obj.destroy()
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testScriptComponent.qml')) return reportError('Test component not loaded 3')
+        if (componentCache.isTypeLoaded('ScriptComponent.qml')) return reportError('Script component not unloaded')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        // Script unloading is not currently implemented
+        //if (componentCache.isScriptLoaded('script.js')) return reportError('Script file already loaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testTopLevelComponent.qml b/tests/auto/qml/qqmlengine/data/testTopLevelComponent.qml
new file mode 100644
index 0000000000..6cf8ec4203
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testTopLevelComponent.qml
@@ -0,0 +1,50 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testTopLevelComponent.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('TopLevelComponent.qml')) return reportError('Top-level component already loaded')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('TopLevelComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testTopLevelComponent.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('TopLevelComponent.qml')) return reportError('Top-level component not loaded')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var internalComp = comp.createObject()
+        if (!internalComp) return reportError('Invalid component')
+
+        var obj = internalComp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.foo != 'bar') return reportError('Invalid object 2')
+        if (obj.bar != 'baz') return reportError('Invalid object 3')
+
+        internalComp.destroy()
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testTopLevelComponent.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('TopLevelComponent.qml')) return reportError('Top-level component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+        if (!obj) return reportError('Invalid object 4')
+        if (obj.foo != 'bar') return reportError('Invalid object 5')
+        if (obj.bar != 'baz') return reportError('Invalid object 6')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testTopLevelComponent.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('TopLevelComponent.qml')) return reportError('Top-level component not unloaded')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testTransientComponent.1.qml b/tests/auto/qml/qqmlengine/data/testTransientComponent.1.qml
new file mode 100644
index 0000000000..d3e6ffd7cf
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testTransientComponent.1.qml
@@ -0,0 +1,34 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testTransientComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Transient component already loaded')
+
+        var comp = Qt.createComponent('VMEExtendVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testTransientComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Transient component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return
+        if (obj.foo != 'bar') return reportError('Invalid object')
+        if (obj.bar != 'baz') return reportError('Invalid object 2')
+
+        obj.destroy()
+        if (!componentCache.isTypeLoaded('testTransientComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Transient component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testTransientComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Transient component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testTransientComponent.2.qml b/tests/auto/qml/qqmlengine/data/testTransientComponent.2.qml
new file mode 100644
index 0000000000..acb0113e61
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testTransientComponent.2.qml
@@ -0,0 +1,36 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testTransientComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Transient component already loaded')
+
+        var comp = Qt.createComponent('VMEExtendVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testTransientComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Transient component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return
+        if (obj.foo != 'bar') return reportError('Invalid object')
+        if (obj.bar != 'baz') return reportError('Invalid object 2')
+
+        comp.destroy()
+        if (!componentCache.isTypeLoaded('testTransientComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Transient component already unloaded')
+        if (obj.foo != 'bar') return reportError('Invalid object 3')
+        if (obj.bar != 'baz') return reportError('Invalid object 4')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testTransientComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Transient component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMEAggregateEmptyComponent.1.qml b/tests/auto/qml/qqmlengine/data/testVMEAggregateEmptyComponent.1.qml
new file mode 100644
index 0000000000..a5beede469
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMEAggregateEmptyComponent.1.qml
@@ -0,0 +1,39 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateEmptyComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEAggregateEmptyComponent.qml')) return reportError('Aggregate component already loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('VMEAggregateEmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateEmptyComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEAggregateEmptyComponent.qml')) return reportError('Aggregate component not loaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.children[0].x == undefined) return reportError('Invalid object 2')
+        if (obj.bar != 'baz') return reportError('Invalid object 3')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateEmptyComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEAggregateEmptyComponent.qml')) return reportError('Aggregate component already unloaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateEmptyComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEAggregateEmptyComponent.qml')) return reportError('Aggregate component not unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMEAggregateEmptyComponent.2.qml b/tests/auto/qml/qqmlengine/data/testVMEAggregateEmptyComponent.2.qml
new file mode 100644
index 0000000000..4c8e52f251
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMEAggregateEmptyComponent.2.qml
@@ -0,0 +1,42 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateEmptyComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEAggregateEmptyComponent.qml')) return reportError('Aggregate component already loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('VMEAggregateEmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateEmptyComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEAggregateEmptyComponent.qml')) return reportError('Aggregate component not loaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.children[0].x == undefined) return reportError('Invalid object 2')
+        if (obj.bar != 'baz') return reportError('Invalid object 3')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateEmptyComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEAggregateEmptyComponent.qml')) return reportError('Aggregate component already unloaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+        if (!obj) return reportError('Invalid object 4')
+        if (obj.children[0].x == undefined) return reportError('Invalid object 5')
+        if (obj.bar != 'baz') return reportError('Invalid object 6')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateEmptyComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEAggregateEmptyComponent.qml')) return reportError('Aggregate component not unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMEAggregateVMEComponent.1.qml b/tests/auto/qml/qqmlengine/data/testVMEAggregateVMEComponent.1.qml
new file mode 100644
index 0000000000..983d6e824c
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMEAggregateVMEComponent.1.qml
@@ -0,0 +1,39 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateVMEComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Aggregate component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('VMEAggregateVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateVMEComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEAggregateVMEComponent.qml')) return reportError('Aggregate component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.foo != 'bar') return reportError('Invalid object 2')
+        if (obj.children[0].foo != 'bar') return reportError('Invalid object 3')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateVMEComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEAggregateVMEComponent.qml')) return reportError('Aggregate component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateVMEComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEAggregateVMEComponent.qml')) return reportError('Aggregate component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMEAggregateVMEComponent.2.qml b/tests/auto/qml/qqmlengine/data/testVMEAggregateVMEComponent.2.qml
new file mode 100644
index 0000000000..fc8e5a0cd4
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMEAggregateVMEComponent.2.qml
@@ -0,0 +1,42 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateVMEComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Aggregate component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('VMEAggregateVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateVMEComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEAggregateVMEComponent.qml')) return reportError('Aggregate component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.foo != 'bar') return reportError('Invalid object 2')
+        if (obj.children[0].foo != 'bar') return reportError('Invalid object 3')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateVMEComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEAggregateVMEComponent.qml')) return reportError('Aggregate component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+        if (!obj) return reportError('Invalid object r4')
+        if (obj.foo != 'bar') return reportError('Invalid object 5')
+        if (obj.children[0].foo != 'bar') return reportError('Invalid object 6')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEAggregateVMEComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEAggregateVMEComponent.qml')) return reportError('Aggregate component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMEComponent.1.qml b/tests/auto/qml/qqmlengine/data/testVMEComponent.1.qml
new file mode 100644
index 0000000000..fcfd05c51f
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMEComponent.1.qml
@@ -0,0 +1,34 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('VMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.foo != 'bar') return reportError('Invalid object 2')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMEComponent.2.qml b/tests/auto/qml/qqmlengine/data/testVMEComponent.2.qml
new file mode 100644
index 0000000000..f434406eec
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMEComponent.2.qml
@@ -0,0 +1,36 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('VMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.foo != 'bar') return reportError('Invalid object 2')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+        if (!obj) return reportError('Invalid object 3')
+        if (obj.foo != 'bar') return reportError('Invalid object 4')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMEExtendEmptyComponent.1.qml b/tests/auto/qml/qqmlengine/data/testVMEExtendEmptyComponent.1.qml
new file mode 100644
index 0000000000..1dcaec90e6
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMEExtendEmptyComponent.1.qml
@@ -0,0 +1,39 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendEmptyComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEExtendEmptyComponent.qml')) return reportError('Extend component already loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('VMEExtendEmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendEmptyComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEExtendEmptyComponent.qml')) return reportError('Extend component not loaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+        if (obj.bar != 'baz') return reportError('Invalid object 3')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendEmptyComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEExtendEmptyComponent.qml')) return reportError('Extend component already unloaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendEmptyComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEExtendEmptyComponent.qml')) return reportError('Extend component not unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMEExtendEmptyComponent.2.qml b/tests/auto/qml/qqmlengine/data/testVMEExtendEmptyComponent.2.qml
new file mode 100644
index 0000000000..fd7d7e454c
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMEExtendEmptyComponent.2.qml
@@ -0,0 +1,42 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendEmptyComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEExtendEmptyComponent.qml')) return reportError('Extend component already loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('VMEExtendEmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendEmptyComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEExtendEmptyComponent.qml')) return reportError('Extend component not loaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+        if (obj.bar != 'baz') return reportError('Invalid object 3')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendEmptyComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEExtendEmptyComponent.qml')) return reportError('Extend component already unloaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+        if (!obj) return reportError('Invalid object 4')
+        if (obj.x == undefined) return reportError('Invalid object 5')
+        if (obj.bar != 'baz') return reportError('Invalid object 6')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendEmptyComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEExtendEmptyComponent.qml')) return reportError('Extend component not unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMEExtendVMEComponent.1.qml b/tests/auto/qml/qqmlengine/data/testVMEExtendVMEComponent.1.qml
new file mode 100644
index 0000000000..d2dab32fc9
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMEExtendVMEComponent.1.qml
@@ -0,0 +1,39 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendVMEComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('VMEExtendVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendVMEComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.foo != 'bar') return reportError('Invalid object 2')
+        if (obj.bar != 'baz') return reportError('Invalid object 3')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendVMEComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendVMEComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMEExtendVMEComponent.2.qml b/tests/auto/qml/qqmlengine/data/testVMEExtendVMEComponent.2.qml
new file mode 100644
index 0000000000..813e43896c
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMEExtendVMEComponent.2.qml
@@ -0,0 +1,42 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendVMEComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('VMEExtendVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendVMEComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.foo != 'bar') return reportError('Invalid object 2')
+        if (obj.bar != 'baz') return reportError('Invalid object 3')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendVMEComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+        if (!obj) return reportError('Invalid object 4')
+        if (obj.foo != 'bar') return reportError('Invalid object 5')
+        if (obj.bar != 'baz') return reportError('Invalid object 6')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEExtendVMEComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEExtendVMEComponent.qml')) return reportError('Extend component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMEPropertyEmptyComponent.1.qml b/tests/auto/qml/qqmlengine/data/testVMEPropertyEmptyComponent.1.qml
new file mode 100644
index 0000000000..c6f0b7928b
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMEPropertyEmptyComponent.1.qml
@@ -0,0 +1,40 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyEmptyComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEPropertyEmptyComponent.qml')) return reportError('Property component already loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('VMEPropertyEmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyEmptyComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEPropertyEmptyComponent.qml')) return reportError('Property component not loaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.foo != 'bar') return reportError('Invalid object 2')
+        if (obj.p == undefined) return reportError('Invalid object 3')
+        if (obj.p.x == undefined) return reportError('Invalid object 4')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyEmptyComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEPropertyEmptyComponent.qml')) return reportError('Property component already unloaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyEmptyComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEPropertyEmptyComponent.qml')) return reportError('Property component not unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMEPropertyEmptyComponent.2.qml b/tests/auto/qml/qqmlengine/data/testVMEPropertyEmptyComponent.2.qml
new file mode 100644
index 0000000000..255138520c
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMEPropertyEmptyComponent.2.qml
@@ -0,0 +1,44 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyEmptyComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEPropertyEmptyComponent.qml')) return reportError('Property component already loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('VMEPropertyEmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyEmptyComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEPropertyEmptyComponent.qml')) return reportError('Property component not loaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.foo != 'bar') return reportError('Invalid object 2')
+        if (obj.p == undefined) return reportError('Invalid object 3')
+        if (obj.p.x == undefined) return reportError('Invalid object 4')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyEmptyComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEPropertyEmptyComponent.qml')) return reportError('Property component already unloaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+        if (!obj) return reportError('Invalid object 5')
+        if (obj.foo != 'bar') return reportError('Invalid object 6')
+        if (obj.p == undefined) return reportError('Invalid object 7')
+        if (obj.p.x == undefined) return reportError('Invalid object 8')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyEmptyComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEPropertyEmptyComponent.qml')) return reportError('Property component not unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMEPropertyVMEComponent.1.qml b/tests/auto/qml/qqmlengine/data/testVMEPropertyVMEComponent.1.qml
new file mode 100644
index 0000000000..0ad59b32d3
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMEPropertyVMEComponent.1.qml
@@ -0,0 +1,40 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyVMEComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEPropertyVMEComponent.qml')) return reportError('Property component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('VMEPropertyVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyVMEComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEPropertyVMEComponent.qml')) return reportError('Property component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.foo != 'bar') return reportError('Invalid object 2')
+        if (obj.p == undefined) return reportError('Invalid object 3')
+        if (obj.p.foo != 'bar') return reportError('Invalid object 4')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyVMEComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEPropertyVMEComponent.qml')) return reportError('Property component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyVMEComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEPropertyVMEComponent.qml')) return reportError('Property component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMEPropertyVMEComponent.2.qml b/tests/auto/qml/qqmlengine/data/testVMEPropertyVMEComponent.2.qml
new file mode 100644
index 0000000000..60f72a92fe
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMEPropertyVMEComponent.2.qml
@@ -0,0 +1,44 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyVMEComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMEPropertyVMEComponent.qml')) return reportError('Property component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('VMEPropertyVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyVMEComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMEPropertyVMEComponent.qml')) return reportError('Property component not loaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.foo != 'bar') return reportError('Invalid object 2')
+        if (obj.p == undefined) return reportError('Invalid object 3')
+        if (obj.p.foo != 'bar') return reportError('Invalid object 4')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyVMEComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMEPropertyVMEComponent.qml')) return reportError('Property component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+        if (!obj) return reportError('Invalid object 5')
+        if (obj.foo != 'bar') return reportError('Invalid object 6')
+        if (obj.p == undefined) return reportError('Invalid object 7')
+        if (obj.p.foo != 'bar') return reportError('Invalid object 8')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMEPropertyVMEComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMEPropertyVMEComponent.qml')) return reportError('Property component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMETransientEmptyComponent.1.qml b/tests/auto/qml/qqmlengine/data/testVMETransientEmptyComponent.1.qml
new file mode 100644
index 0000000000..6c7f959f49
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMETransientEmptyComponent.1.qml
@@ -0,0 +1,41 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientEmptyComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMETransientEmptyComponent.qml')) return reportError('Transient component already loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('VMETransientEmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientEmptyComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMETransientEmptyComponent.qml')) return reportError('Transient component not loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+        if (!obj.p) return reportError('Invalid object 3')
+        if (obj.p.x == undefined) return reportError('Invalid object 4')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientEmptyComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMETransientEmptyComponent.qml')) return reportError('Transient component already unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientEmptyComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMETransientEmptyComponent.qml')) return reportError('Transient component not unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded 2')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMETransientEmptyComponent.2.qml b/tests/auto/qml/qqmlengine/data/testVMETransientEmptyComponent.2.qml
new file mode 100644
index 0000000000..86060c3998
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMETransientEmptyComponent.2.qml
@@ -0,0 +1,45 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientEmptyComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMETransientEmptyComponent.qml')) return reportError('Transient component already loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var comp = Qt.createComponent('VMETransientEmptyComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientEmptyComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMETransientEmptyComponent.qml')) return reportError('Transient component not loaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+        if (!obj.p) return reportError('Invalid object 3')
+        if (obj.p.x == undefined) return reportError('Invalid object 4')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not loaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientEmptyComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMETransientEmptyComponent.qml')) return reportError('Transient component already unloaded')
+        if (!componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component already unloaded')
+        if (!obj) return reportError('Invalid object 5')
+        if (obj.x == undefined) return reportError('Invalid object 6')
+        if (!obj.p) return reportError('Invalid object 7')
+        if (obj.p.x == undefined) return reportError('Invalid object 8')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientEmptyComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMETransientEmptyComponent.qml')) return reportError('Transient component not unloaded')
+        if (componentCache.isTypeLoaded('EmptyComponent.qml')) return reportError('Empty component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMETransientVMEComponent.1.qml b/tests/auto/qml/qqmlengine/data/testVMETransientVMEComponent.1.qml
new file mode 100644
index 0000000000..c50fd70dec
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMETransientVMEComponent.1.qml
@@ -0,0 +1,41 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientVMEComponent.1.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMETransientVMEComponent.qml')) return reportError('Transient component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('VMETransientVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientVMEComponent.1.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMETransientVMEComponent.qml')) return reportError('Transient component not loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+        if (!obj.p) return reportError('Invalid object 3')
+        if (obj.p.foo != 'bar') return reportError('Invalid object 4')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientVMEComponent.1.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMETransientVMEComponent.qml')) return reportError('Transient component already unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientVMEComponent.1.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMETransientVMEComponent.qml')) return reportError('Transient component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded 2')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/data/testVMETransientVMEComponent.2.qml b/tests/auto/qml/qqmlengine/data/testVMETransientVMEComponent.2.qml
new file mode 100644
index 0000000000..120d249bc0
--- /dev/null
+++ b/tests/auto/qml/qqmlengine/data/testVMETransientVMEComponent.2.qml
@@ -0,0 +1,45 @@
+import QtQuick 2.0
+
+Item {
+    property bool success: false
+
+    function reportError(s) { console.warn(s) }
+
+    Component.onCompleted: {
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientVMEComponent.2.qml')) return reportError('Test component not loaded')
+        if (componentCache.isTypeLoaded('VMETransientVMEComponent.qml')) return reportError('Transient component already loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var comp = Qt.createComponent('VMETransientVMEComponent.qml')
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientVMEComponent.2.qml')) return reportError('Test component not loaded 2')
+        if (!componentCache.isTypeLoaded('VMETransientVMEComponent.qml')) return reportError('Transient component not loaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already loaded')
+
+        var obj = comp.createObject()
+        if (!obj) return reportError('Invalid object')
+        if (obj.x == undefined) return reportError('Invalid object 2')
+        if (!obj.p) return reportError('Invalid object 3')
+        if (obj.p.foo != 'bar') return reportError('Invalid object 4')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not loaded')
+
+        comp.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientVMEComponent.2.qml')) return reportError('Test component not loaded 3')
+        if (!componentCache.isTypeLoaded('VMETransientVMEComponent.qml')) return reportError('Transient component already unloaded')
+        if (!componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component already unloaded')
+        if (!obj) return reportError('Invalid object 5')
+        if (obj.x == undefined) return reportError('Invalid object 6')
+        if (!obj.p) return reportError('Invalid object 7')
+        if (obj.p.foo != 'bar') return reportError('Invalid object 8')
+
+        obj.destroy()
+        componentCache.trim()
+        if (!componentCache.isTypeLoaded('testVMETransientVMEComponent.2.qml')) return reportError('Test component not loaded 4')
+        if (componentCache.isTypeLoaded('VMETransientVMEComponent.qml')) return reportError('Transient component not unloaded')
+        if (componentCache.isTypeLoaded('VMEComponent.qml')) return reportError('VME component not unloaded')
+
+        success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlengine/qqmlengine.pro b/tests/auto/qml/qqmlengine/qqmlengine.pro
index e87b4e30aa..87e2814555 100644
--- a/tests/auto/qml/qqmlengine/qqmlengine.pro
+++ b/tests/auto/qml/qqmlengine/qqmlengine.pro
@@ -2,8 +2,10 @@ CONFIG += testcase
 TARGET = tst_qqmlengine
 macx:CONFIG -= app_bundle
 
+include (../../shared/util.pri)
+
 SOURCES += tst_qqmlengine.cpp 
 
 CONFIG += parallel_test
 
-QT += core-private gui-private qml-private network testlib
+QT += core-private gui-private qml-private v8-private network testlib
diff --git a/tests/auto/qml/qqmlengine/tst_qqmlengine.cpp b/tests/auto/qml/qqmlengine/tst_qqmlengine.cpp
index ab18cdd050..727635ee2c 100644
--- a/tests/auto/qml/qqmlengine/tst_qqmlengine.cpp
+++ b/tests/auto/qml/qqmlengine/tst_qqmlengine.cpp
@@ -39,7 +39,7 @@
 **
 ****************************************************************************/
 
-#include <qtest.h>
+#include "../../shared/util.h"
 #include <QQmlEngine>
 #include <QQmlContext>
 #include <QNetworkAccessManager>
@@ -51,8 +51,10 @@
 #include <QQmlComponent>
 #include <QQmlNetworkAccessManagerFactory>
 #include <QQmlExpression>
+#include <QQmlIncubationController>
+#include <private/qqmlengine_p.h>
 
-class tst_qqmlengine : public QObject
+class tst_qqmlengine : public QQmlDataTest
 {
     Q_OBJECT
 public:
@@ -65,6 +67,8 @@ private slots:
     void contextForObject();
     void offlineStoragePath();
     void clearComponentCache();
+    void trimComponentCache();
+    void trimComponentCache_data();
     void outputWarningsToStandardError();
     void objectOwnership();
     void multipleEngines();
@@ -252,6 +256,122 @@ void tst_qqmlengine::clearComponentCache()
     }
 }
 
+struct ComponentCacheFunctions : public QObject, public QQmlIncubationController
+{
+    Q_OBJECT
+public:
+    QQmlEngine *engine;
+
+    ComponentCacheFunctions(QQmlEngine &e) : engine(&e) {}
+
+    Q_INVOKABLE void trim()
+    {
+        // Wait for any pending deletions to occur
+        QCoreApplication::sendPostedEvents(0, QEvent::DeferredDelete);
+        QCoreApplication::processEvents();
+
+        engine->trimComponentCache();
+    }
+
+    Q_INVOKABLE bool isTypeLoaded(QString file)
+    {
+        return QQmlEnginePrivate::get(engine)->isTypeLoaded(tst_qqmlengine::instance()->testFileUrl(file));
+    }
+
+    Q_INVOKABLE bool isScriptLoaded(QString file)
+    {
+        return QQmlEnginePrivate::get(engine)->isScriptLoaded(tst_qqmlengine::instance()->testFileUrl(file));
+    }
+
+    Q_INVOKABLE void beginIncubation()
+    {
+        startTimer(0);
+    }
+
+    Q_INVOKABLE void waitForIncubation()
+    {
+        while (incubatingObjectCount() > 0) {
+            QCoreApplication::processEvents();
+        }
+    }
+
+private:
+    virtual void timerEvent(QTimerEvent *)
+    {
+        incubateFor(1000);
+    }
+};
+
+void tst_qqmlengine::trimComponentCache()
+{
+    QFETCH(QString, file);
+
+    QQmlEngine engine;
+    ComponentCacheFunctions componentCache(engine);
+    engine.rootContext()->setContextProperty("componentCache", &componentCache);
+    engine.setIncubationController(&componentCache);
+
+    QQmlComponent component(&engine, testFileUrl(file));
+    QVERIFY(component.isReady());
+    QScopedPointer<QObject> object(component.create());
+    QVERIFY(object != 0);
+    QCOMPARE(object->property("success").toBool(), true);
+}
+
+void tst_qqmlengine::trimComponentCache_data()
+{
+    QTest::addColumn<QString>("file");
+
+    // The various tests here are for two types of components: those that are
+    // empty apart from their inherited elements, and those that define new properties.
+    // For each there are five types of composition: extension, aggregation,
+    // aggregation via component, property and object-created-via-transient-component.
+    foreach (const QString &test, (QStringList() << "EmptyComponent"
+                                                 << "VMEComponent"
+                                                 << "EmptyExtendEmptyComponent"
+                                                 << "VMEExtendEmptyComponent"
+                                                 << "EmptyExtendVMEComponent"
+                                                 << "VMEExtendVMEComponent"
+                                                 << "EmptyAggregateEmptyComponent"
+                                                 << "VMEAggregateEmptyComponent"
+                                                 << "EmptyAggregateVMEComponent"
+                                                 << "VMEAggregateVMEComponent"
+                                                 << "EmptyPropertyEmptyComponent"
+                                                 << "VMEPropertyEmptyComponent"
+                                                 << "EmptyPropertyVMEComponent"
+                                                 << "VMEPropertyVMEComponent"
+                                                 << "VMETransientEmptyComponent"
+                                                 << "VMETransientVMEComponent")) {
+        // For these cases, we first test that the component instance keeps the components
+        // referenced, and then that the instantiated object keeps the components referenced
+        for (int i = 1; i <= 2; ++i) {
+            QString name(QString("%1-%2").arg(test).arg(i));
+            QString file(QString("test%1.%2.qml").arg(test).arg(i));
+            QTest::newRow(name.toLatin1().constData()) << file;
+        }
+    }
+
+    // Test that a transient component is correctly referenced
+    QTest::newRow("TransientComponent-1") << "testTransientComponent.1.qml";
+    QTest::newRow("TransientComponent-2") << "testTransientComponent.2.qml";
+
+    // Test that components can be reloaded after unloading
+    QTest::newRow("ReloadComponent") << "testReloadComponent.qml";
+
+    // Test that components are correctly referenced when dynamically loaded
+    QTest::newRow("LoaderComponent") << "testLoaderComponent.qml";
+
+    // Test that components are correctly referenced when incubated
+    QTest::newRow("IncubatedComponent") << "testIncubatedComponent.qml";
+
+    // Test that a top-level omponents is correctly referenced
+    QTest::newRow("TopLevelComponent") << "testTopLevelComponent.qml";
+
+    // TODO:
+    // Test that scripts are unloaded when no longer referenced
+    QTest::newRow("ScriptComponent") << "testScriptComponent.qml";
+}
+
 static QStringList warnings;
 static void msgHandler(QtMsgType, const char *warning)
 {