Fix Persistent/WeakValue API

Don't use unprotected Values in the API anymore.

Change-Id: I8851628227fca374de24701bc8ee0908b5ae3923
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

48 files changed, 425 insertions, 327 deletions

diff --git a/src/imports/localstorage/plugin.cpp b/src/imports/localstorage/plugin.cpp
index 211809e59c..bac76b0657 100644
--- a/src/imports/localstorage/plugin.cpp
+++ b/src/imports/localstorage/plugin.cpp
@@ -297,7 +297,8 @@ static ReturnedValue qmlsqldatabase_executeSql(SimpleCallContext *ctx)
         }
         if (query.exec()) {
             QQmlSqlDatabaseWrapper *rows = new (ctx->engine->memoryManager) QQmlSqlDatabaseWrapper(engine);
-            rows->setPrototype(databaseData(engine)->rowsProto.value().asObject());
+            QV4::ScopedObject p(scope, databaseData(engine)->rowsProto.value());
+            rows->setPrototype(p.getPointer());
             rows->type = QQmlSqlDatabaseWrapper::Rows;
             rows->database = db;
             rows->sqlQuery = query;
@@ -344,7 +345,8 @@ static ReturnedValue qmlsqldatabase_changeVersion(SimpleCallContext *ctx)
         V4THROW_SQL(SQLEXCEPTION_VERSION_ERR, QQmlEngine::tr("Version mismatch: expected %1, found %2").arg(from_version).arg(r->version));
 
     QQmlSqlDatabaseWrapper *w = new (ctx->engine->memoryManager) QQmlSqlDatabaseWrapper(engine);
-    w->setPrototype(databaseData(engine)->queryProto.value().asObject());
+    QV4::ScopedObject p(scope, databaseData(engine)->queryProto.value());
+    w->setPrototype(p.getPointer());
     w->type = QQmlSqlDatabaseWrapper::Query;
     w->database = db;
     w->version = r->version;
@@ -401,7 +403,8 @@ static ReturnedValue qmlsqldatabase_transaction_shared(SimpleCallContext *ctx, b
     QSqlDatabase db = r->database;
 
     QQmlSqlDatabaseWrapper *w = new (ctx->engine->memoryManager) QQmlSqlDatabaseWrapper(engine);
-    w->setPrototype(databaseData(engine)->queryProto.value().asObject());
+    QV4::ScopedObject p(scope, databaseData(engine)->queryProto.value());
+    w->setPrototype(p.getPointer());
     w->type = QQmlSqlDatabaseWrapper::Query;
     w->database = db;
     w->version = r->version;
@@ -684,7 +687,8 @@ void QQuickLocalStorage::openDatabaseSync(QQmlV4Function *args)
     }
 
     QQmlSqlDatabaseWrapper *db = new (ctx->engine->memoryManager) QQmlSqlDatabaseWrapper(engine);
-    db->setPrototype(databaseData(engine)->databaseProto.value().asObject());
+    QV4::ScopedObject p(scope, databaseData(engine)->databaseProto.value());
+    db->setPrototype(p.getPointer());
     db->database = database;
     db->version = version;
 
diff --git a/src/particles/qquickv4particledata.cpp b/src/particles/qquickv4particledata.cpp
index 9f95edff3b..8cbe42bdd3 100644
--- a/src/particles/qquickv4particledata.cpp
+++ b/src/particles/qquickv4particledata.cpp
@@ -512,9 +512,11 @@ QQuickV4ParticleData::QQuickV4ParticleData(QV8Engine* engine, QQuickParticleData
 
     QV8ParticleDataDeletable *d = particleV8Data(engine);
     QV4::ExecutionEngine *v4 = QV8Engine::getV4(engine);
-    QV4::Object *o = new (v4->memoryManager) QV4ParticleData(v4, datum);
-    o->setPrototype(d->proto.value().asObject());
-    m_v4Value = QV4::Value::fromObject(o);
+    QV4::Scope scope(v4);
+    QV4::ScopedObject o(scope, new (v4->memoryManager) QV4ParticleData(v4, datum));
+    QV4::ScopedObject p(scope, d->proto.value());
+    o->setPrototype(p.getPointer());
+    m_v4Value = o;
 }
 
 QQuickV4ParticleData::~QQuickV4ParticleData()
@@ -523,7 +525,7 @@ QQuickV4ParticleData::~QQuickV4ParticleData()
 
 QQmlV4Handle QQuickV4ParticleData::v4Value()
 {
-    return QQmlV4Handle(m_v4Value);
+    return QQmlV4Handle(QV4::Value::fromReturnedValue(m_v4Value.value()));
 }
 
 QT_END_NAMESPACE
diff --git a/src/qml/debugger/qqmlenginedebugservice.cpp b/src/qml/debugger/qqmlenginedebugservice.cpp
index 2b013129ce..5f3db9fb65 100644
--- a/src/qml/debugger/qqmlenginedebugservice.cpp
+++ b/src/qml/debugger/qqmlenginedebugservice.cpp
@@ -742,8 +742,10 @@ bool QQmlEngineDebugService::setMethodBody(int objectId, const QString &method,
     Q_ASSERT(vmeMetaObject); // the fact we found the property above should guarentee this
 
     int lineNumber = vmeMetaObject->vmeMethodLineNumber(prop->coreIndex);
-    vmeMetaObject->setVmeMethod(prop->coreIndex,
-                                QQmlExpressionPrivate::evalFunction(contextData, object, jsfunction, contextData->url.toString(), lineNumber));
+    QV4::ExecutionEngine *v4 = QV8Engine::getV4(qmlEngine(object)->handle());
+    QV4::Scope scope(v4);
+    QV4::ScopedValue v(scope, QQmlExpressionPrivate::evalFunction(contextData, object, jsfunction, contextData->url.toString(), lineNumber));
+    vmeMetaObject->setVmeMethod(prop->coreIndex, v);
     return true;
 }
 
diff --git a/src/qml/jsapi/qjsengine.cpp b/src/qml/jsapi/qjsengine.cpp
index f99463256e..59a6a14e81 100644
--- a/src/qml/jsapi/qjsengine.cpp
+++ b/src/qml/jsapi/qjsengine.cpp
@@ -286,7 +286,9 @@ QJSValue QJSEngine::evaluate(const QString& program, const QString& fileName, in
 */
 QJSValue QJSEngine::newObject()
 {
-    return new QJSValuePrivate(d->m_v4Engine->newObject()->getPointer());
+    QV4::Scope scope(d->m_v4Engine);
+    QV4::ScopedValue v(scope, d->m_v4Engine->newObject());
+    return new QJSValuePrivate(d->m_v4Engine, v);
 }
 
 /*!
@@ -301,7 +303,7 @@ QJSValue QJSEngine::newArray(uint length)
     if (length < 0x1000)
         array->arrayReserve(length);
     array->setArrayLengthUnchecked(length);
-    return new QJSValuePrivate(d->m_v4Engine, array.asValue());
+    return new QJSValuePrivate(d->m_v4Engine, array);
 }
 
 /*!
@@ -346,7 +348,10 @@ QJSValue QJSEngine::newQObject(QObject *object)
 */
 QJSValue QJSEngine::globalObject() const
 {
-    return new QJSValuePrivate(d->m_v4Engine->globalObject);
+    Q_D(const QJSEngine);
+    QV4::Scope scope(d->m_v4Engine);
+    QV4::ScopedValue v(scope, d->m_v4Engine->globalObject);
+    return new QJSValuePrivate(d->m_v4Engine, v);
 }
 
 /*!
@@ -356,7 +361,9 @@ QJSValue QJSEngine::globalObject() const
 QJSValue QJSEngine::create(int type, const void *ptr)
 {
     Q_D(QJSEngine);
-    return new QJSValuePrivate(d->m_v4Engine, QV4::Value::fromReturnedValue(d->metaTypeToJS(type, ptr)));
+    QV4::Scope scope(d->m_v4Engine);
+    QV4::ScopedValue v(scope, d->metaTypeToJS(type, ptr));
+    return new QJSValuePrivate(d->m_v4Engine, v);
 }
 
 /*!
diff --git a/src/qml/jsapi/qjsvalue.cpp b/src/qml/jsapi/qjsvalue.cpp
index 56a01a584d..9c06f403b5 100644
--- a/src/qml/jsapi/qjsvalue.cpp
+++ b/src/qml/jsapi/qjsvalue.cpp
@@ -149,7 +149,7 @@ using namespace QV4;
   Constructs a new QJSValue with a boolean \a value.
 */
 QJSValue::QJSValue(bool value)
-    : d(new QJSValuePrivate(0, Value::fromBoolean(value)))
+    : d(new QJSValuePrivate(Encode(value)))
 {
 }
 
@@ -162,7 +162,7 @@ QJSValue::QJSValue(QJSValuePrivate *dd)
   Constructs a new QJSValue with a number \a value.
 */
 QJSValue::QJSValue(int value)
-    : d(new QJSValuePrivate(0, Value::fromInt32(value)))
+    : d(new QJSValuePrivate(Encode(value)))
 {
 }
 
@@ -170,7 +170,7 @@ QJSValue::QJSValue(int value)
   Constructs a new QJSValue with a number \a value.
 */
 QJSValue::QJSValue(uint value)
-    : d(new QJSValuePrivate(0, Value::fromUInt32(value)))
+    : d(new QJSValuePrivate(Encode(value)))
 {
 }
 
@@ -178,7 +178,7 @@ QJSValue::QJSValue(uint value)
   Constructs a new QJSValue with a number \a value.
 */
 QJSValue::QJSValue(double value)
-    : d(new QJSValuePrivate(0, Value::fromDouble(value)))
+    : d(new QJSValuePrivate(Encode(value)))
 {
 }
 
@@ -194,7 +194,7 @@ QJSValue::QJSValue(const QString& value)
   Constructs a new QJSValue with a special \a value.
 */
 QJSValue::QJSValue(SpecialValue value)
-    : d(new QJSValuePrivate(0, value == UndefinedValue ? Value::undefinedValue() : Value::nullValue()))
+    : d(new QJSValuePrivate(value == UndefinedValue ? Encode::undefined() : Encode::null()))
 {
 }
 
@@ -673,7 +673,7 @@ QJSValue QJSValue::prototype() const
     Scoped<Object> p(scope, o->prototype());
     if (!p)
         return QJSValue(NullValue);
-    return new QJSValuePrivate(o->internalClass->engine, p.asValue());
+    return new QJSValuePrivate(o->internalClass->engine, p);
 }
 
 /*!
diff --git a/src/qml/jsapi/qjsvalue_p.h b/src/qml/jsapi/qjsvalue_p.h
index a0dfa010ab..ec3f61ef20 100644
--- a/src/qml/jsapi/qjsvalue_p.h
+++ b/src/qml/jsapi/qjsvalue_p.h
@@ -69,19 +69,18 @@ QT_BEGIN_NAMESPACE
 class Q_QML_PRIVATE_EXPORT QJSValuePrivate : public QV4::PersistentValuePrivate
 {
 public:
-    QJSValuePrivate(QV4::ExecutionEngine *engine, const QV4::Value &v)
-        : PersistentValuePrivate(v, engine)
+    QJSValuePrivate(QV4::ExecutionEngine *engine, const QV4::ValueRef v)
+        : PersistentValuePrivate(v.asReturnedValue(), engine)
+    {
+        Q_ASSERT(!value.isEmpty());
+    }
+    QJSValuePrivate(QV4::ReturnedValue v)
+        : PersistentValuePrivate(v)
     {
         Q_ASSERT(!value.isEmpty());
     }
-    QJSValuePrivate(QV4::Object *o)
-        : PersistentValuePrivate(QV4::Value::fromObject(o))
-    { }
-    QJSValuePrivate(QV4::String *s)
-        : PersistentValuePrivate(QV4::Value::fromString(s))
-    { }
     QJSValuePrivate(const QString &s)
-        : PersistentValuePrivate(QV4::Value::undefinedValue())
+        : PersistentValuePrivate(QV4::Encode::undefined())
         , string(0, s)
     {
         value = QV4::Value::fromString(&string);
diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index 821e88ee61..363f0a45c0 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -101,6 +101,8 @@ ExecutionEngine::ExecutionEngine(QQmlJS::EvalISelFactory *factory)
 {
     MemoryManager::GCBlocker gcBlocker(memoryManager);
 
+    exceptionValue = Encode::undefined();
+
     if (!factory) {
 
 #ifdef V4_ENABLE_JIT
@@ -735,6 +737,8 @@ void ExecutionEngine::markObjects()
     typeErrorCtor.mark();
     uRIErrorCtor.mark();
 
+    exceptionValue.mark();
+
     thrower->mark();
 
     if (m_qmlExtensions)
diff --git a/src/qml/jsruntime/qv4engine_p.h b/src/qml/jsruntime/qv4engine_p.h
index ec2c6f394d..90639d582c 100644
--- a/src/qml/jsruntime/qv4engine_p.h
+++ b/src/qml/jsruntime/qv4engine_p.h
@@ -236,6 +236,8 @@ struct Q_QML_EXPORT ExecutionEngine
 
     RegExpCache *regExpCache;
 
+    SafeValue exceptionValue;
+
     // Scarce resources are "exceptionally high cost" QVariant types where allowing the
     // normal JavaScript GC to clean them up is likely to lead to out-of-memory or other
     // out-of-resource situations.  When such a resource is passed into JavaScript we
diff --git a/src/qml/jsruntime/qv4exception.cpp b/src/qml/jsruntime/qv4exception.cpp
index 725a046b71..35a4f726e2 100644
--- a/src/qml/jsruntime/qv4exception.cpp
+++ b/src/qml/jsruntime/qv4exception.cpp
@@ -88,8 +88,8 @@ void Exception::throwException(ExecutionContext *context, const Value &value)
 
 Exception::Exception(ExecutionContext *throwingContext, const Value &exceptionValue)
     : e(throwingContext->engine)
-    , exception(exceptionValue)
 {
+    e->exceptionValue = exceptionValue;
     this->throwingContext = throwingContext->engine->current;
     accepted = false;
     if (ErrorObject *error = exceptionValue.asErrorObject())
@@ -101,6 +101,7 @@ Exception::Exception(ExecutionContext *throwingContext, const Value &exceptionVa
 Exception::~Exception()
 {
     assert(accepted);
+    e->exceptionValue = Value::undefinedValue();
 }
 
 void Exception::accept(ExecutionContext *catchingContext)
diff --git a/src/qml/jsruntime/qv4exception_p.h b/src/qml/jsruntime/qv4exception_p.h
index 75246fa147..eaeebf7abd 100644
--- a/src/qml/jsruntime/qv4exception_p.h
+++ b/src/qml/jsruntime/qv4exception_p.h
@@ -58,7 +58,7 @@ struct Q_QML_EXPORT Exception {
 
     void partiallyUnwindContext(ExecutionContext *catchingContext);
 
-    ReturnedValue value() const { return exception.value().asReturnedValue(); }
+    ReturnedValue value() const { return e->exceptionValue.asReturnedValue(); }
 
     ExecutionEngine::StackTrace stackTrace() const { return m_stackTrace; }
     ExecutionEngine *engine() const { return e; }
@@ -71,7 +71,6 @@ private:
     ExecutionEngine *e;
     ExecutionContext *throwingContext;
     bool accepted;
-    PersistentValue exception;
     ExecutionEngine::StackTrace m_stackTrace;
     static void throwInternal(ExecutionContext *throwingContext, const Value &exceptionValue);
 };
diff --git a/src/qml/jsruntime/qv4include.cpp b/src/qml/jsruntime/qv4include.cpp
index 681ae5990d..d6f01bf369 100644
--- a/src/qml/jsruntime/qv4include.cpp
+++ b/src/qml/jsruntime/qv4include.cpp
@@ -62,9 +62,9 @@ QV4Include::QV4Include(const QUrl &url, QV8Engine *engine, QQmlContextData *cont
                        const QV4::Value &qmlglobal, const QV4::Value &callback)
     : v4(QV8Engine::getV4(engine)), m_network(0), m_reply(0), m_url(url), m_redirectCount(0), m_context(context)
 {
-    m_qmlglobal = qmlglobal;
+    m_qmlglobal = qmlglobal.asReturnedValue();
     if (callback.asFunctionObject())
-        m_callbackFunction = callback;
+        m_callbackFunction = callback.asReturnedValue();
 
     m_resultObject = resultValue(v4);
 
@@ -119,7 +119,7 @@ void QV4Include::callback(const QV4::Value &callback, const QV4::Value &status)
 
 QV4::ReturnedValue QV4Include::result()
 {
-    return m_resultObject.value().asReturnedValue();
+    return m_resultObject.value();
 }
 
 #define INCLUDE_MAXIMUM_REDIRECT_RECURSION 15
@@ -143,32 +143,34 @@ void QV4Include::finished()
     }
 
     QV4::Scope scope(v4);
+    QV4::ScopedObject resultObj(scope, m_resultObject.value());
     if (m_reply->error() == QNetworkReply::NoError) {
         QByteArray data = m_reply->readAll();
 
         QString code = QString::fromUtf8(data);
         QQmlScript::Parser::extractPragmas(code);
 
-        QV4::Script script(v4, m_qmlglobal.value().asObject(), code, m_url.toString());
+        QV4::ScopedObject qmlglobal(scope, m_qmlglobal.value());
+        QV4::Script script(v4, qmlglobal, code, m_url.toString());
 
         QV4::ExecutionContext *ctx = v4->current;
-        QV4::Scoped<QV4::Object> o(scope, m_resultObject.value());
         QV4::ScopedString status(scope, v4->newString("status"));
         try {
             script.parse();
             script.run();
-            o->put(status, QV4::ScopedValue(scope, QV4::Value::fromInt32(Ok)));
+            resultObj->put(status, QV4::ScopedValue(scope, QV4::Value::fromInt32(Ok)));
         } catch (QV4::Exception &e) {
             e.accept(ctx);
-            o->put(status, QV4::ScopedValue(scope, QV4::Value::fromInt32(Exception)));
+            resultObj->put(status, QV4::ScopedValue(scope, QV4::Value::fromInt32(Exception)));
             QV4::ScopedValue ex(scope, e.value());
-            o->put(QV4::ScopedString(scope, v4->newString("exception")), ex);
+            resultObj->put(QV4::ScopedString(scope, v4->newString("exception")), ex);
         }
     } else {
-        m_resultObject.value().asObject()->put(QV4::ScopedString(scope, v4->newString("status")), QV4::ScopedValue(scope, QV4::Value::fromInt32(NetworkError)));
+        resultObj->put(QV4::ScopedString(scope, v4->newString("status")), QV4::ScopedValue(scope, QV4::Value::fromInt32(NetworkError)));
     }
 
-    callback(m_callbackFunction.value(), m_resultObject.value());
+    QV4::ScopedValue cb(scope, m_callbackFunction.value());
+    callback(cb, resultObj.asValue());
 
     disconnect();
     deleteLater();
@@ -216,7 +218,7 @@ QV4::ReturnedValue QV4Include::method_include(QV4::SimpleCallContext *ctx)
             QString code = QString::fromUtf8(data);
             QQmlScript::Parser::extractPragmas(code);
 
-            QV4::Script script(v4, qmlcontextobject.getPointer(), code, url.toString());
+            QV4::Script script(v4, qmlcontextobject, code, url.toString());
 
             QV4::ExecutionContext *ctx = v4->current;
             try {
diff --git a/src/qml/jsruntime/qv4qobjectwrapper.cpp b/src/qml/jsruntime/qv4qobjectwrapper.cpp
index 7e31797627..c0c68bb6fd 100644
--- a/src/qml/jsruntime/qv4qobjectwrapper.cpp
+++ b/src/qml/jsruntime/qv4qobjectwrapper.cpp
@@ -400,11 +400,14 @@ ReturnedValue QObjectWrapper::getQmlProperty(ExecutionContext *ctx, QQmlContextD
     return wrapper->getQmlProperty(ctx, qmlContext, name, revisionMode, hasProperty);
 }
 
-bool QObjectWrapper::setQmlProperty(ExecutionContext *ctx, QQmlContextData *qmlContext, QObject *object, String *name, QObjectWrapper::RevisionMode revisionMode, const Value &value)
+bool QObjectWrapper::setQmlProperty(ExecutionContext *ctx, QQmlContextData *qmlContext, QObject *object, String *name,
+                                    QObjectWrapper::RevisionMode revisionMode, const ValueRef value)
 {
     if (QQmlData::wasDeleted(object))
         return false;
 
+    QV4::Scope scope(ctx);
+
     QQmlPropertyData local;
     QQmlPropertyData *result = 0;
     {
@@ -427,7 +430,8 @@ bool QObjectWrapper::setQmlProperty(ExecutionContext *ctx, QQmlContextData *qmlC
     }
 
     QQmlBinding *newBinding = 0;
-    if (FunctionObject *f = value.asFunctionObject()) {
+    QV4::ScopedFunctionObject f(scope, value);
+    if (f) {
         if (!f->bindingKeyFlag) {
             if (!result->isVarProperty() && result->propType != qMetaTypeId<QJSValue>()) {
                 // assigning a JS function to a non var or QJSValue property or is not allowed.
@@ -461,7 +465,7 @@ bool QObjectWrapper::setQmlProperty(ExecutionContext *ctx, QQmlContextData *qmlC
         // allow assignment of "special" values (null, undefined, function) to var properties
         QQmlVMEMetaObject *vmemo = QQmlVMEMetaObject::get(object);
         Q_ASSERT(vmemo);
-        vmemo->setVMEProperty(result->coreIndex, value);
+        vmemo->setVMEProperty(result->coreIndex, *value);
         return true;
     }
 
@@ -472,46 +476,46 @@ bool QObjectWrapper::setQmlProperty(ExecutionContext *ctx, QQmlContextData *qmlC
     void *argv[] = { &o, 0, &status, &flags }; \
     QMetaObject::metacall(object, QMetaObject::WriteProperty, result->coreIndex, argv);
 
-    if (value.isNull() && result->isQObject()) {
+    if (value->isNull() && result->isQObject()) {
         PROPERTY_STORE(QObject*, 0);
-    } else if (value.isUndefined() && result->isResettable()) {
+    } else if (value->isUndefined() && result->isResettable()) {
         void *a[] = { 0 };
         QMetaObject::metacall(object, QMetaObject::ResetProperty, result->coreIndex, a);
-    } else if (value.isUndefined() && result->propType == qMetaTypeId<QVariant>()) {
+    } else if (value->isUndefined() && result->propType == qMetaTypeId<QVariant>()) {
         PROPERTY_STORE(QVariant, QVariant());
-    } else if (value.isUndefined() && result->propType == QMetaType::QJsonValue) {
+    } else if (value->isUndefined() && result->propType == QMetaType::QJsonValue) {
         PROPERTY_STORE(QJsonValue, QJsonValue(QJsonValue::Undefined));
     } else if (!newBinding && result->propType == qMetaTypeId<QJSValue>()) {
         PROPERTY_STORE(QJSValue, new QJSValuePrivate(ctx->engine, value));
-    } else if (value.isUndefined()) {
+    } else if (value->isUndefined()) {
         QString error = QLatin1String("Cannot assign [undefined] to ");
         if (!QMetaType::typeName(result->propType))
             error += QLatin1String("[unknown property type]");
         else
             error += QLatin1String(QMetaType::typeName(result->propType));
         ctx->throwError(error);
-    } else if (value.asFunctionObject()) {
+    } else if (value->asFunctionObject()) {
         // this is handled by the binding creation above
-    } else if (result->propType == QMetaType::Int && value.isNumber()) {
-        PROPERTY_STORE(int, qRound(value.asDouble()));
-    } else if (result->propType == QMetaType::QReal && value.isNumber()) {
-        PROPERTY_STORE(qreal, qreal(value.asDouble()));
-    } else if (result->propType == QMetaType::Float && value.isNumber()) {
-        PROPERTY_STORE(float, float(value.asDouble()));
-    } else if (result->propType == QMetaType::Double && value.isNumber()) {
-        PROPERTY_STORE(double, double(value.asDouble()));
-    } else if (result->propType == QMetaType::QString && value.isString()) {
-        PROPERTY_STORE(QString, value.toQStringNoThrow());
+    } else if (result->propType == QMetaType::Int && value->isNumber()) {
+        PROPERTY_STORE(int, qRound(value->asDouble()));
+    } else if (result->propType == QMetaType::QReal && value->isNumber()) {
+        PROPERTY_STORE(qreal, qreal(value->asDouble()));
+    } else if (result->propType == QMetaType::Float && value->isNumber()) {
+        PROPERTY_STORE(float, float(value->asDouble()));
+    } else if (result->propType == QMetaType::Double && value->isNumber()) {
+        PROPERTY_STORE(double, double(value->asDouble()));
+    } else if (result->propType == QMetaType::QString && value->isString()) {
+        PROPERTY_STORE(QString, value->toQStringNoThrow());
     } else if (result->isVarProperty()) {
         QQmlVMEMetaObject *vmemo = QQmlVMEMetaObject::get(object);
         Q_ASSERT(vmemo);
-        vmemo->setVMEProperty(result->coreIndex, value);
+        vmemo->setVMEProperty(result->coreIndex, *value);
     } else {
         QVariant v;
         if (result->isQList())
-            v = ctx->engine->v8Engine->toVariant(value, qMetaTypeId<QList<QObject *> >());
+            v = ctx->engine->v8Engine->toVariant(*value, qMetaTypeId<QList<QObject *> >());
         else
-            v = ctx->engine->v8Engine->toVariant(value, result->propType);
+            v = ctx->engine->v8Engine->toVariant(*value, result->propType);
 
         QQmlContextData *callingQmlContext = QV4::QmlContextWrapper::callingContext(ctx->engine);
         if (!QQmlPropertyPrivate::write(object, *result, v, callingQmlContext)) {
@@ -547,7 +551,7 @@ ReturnedValue QObjectWrapper::wrap(ExecutionEngine *engine, QObject *object)
 
     if (ddata->jsEngineId == engine->m_engineId && !ddata->jsWrapper.isUndefined()) {
         // We own the JS object
-        return ddata->jsWrapper.value().asReturnedValue();
+        return ddata->jsWrapper.value();
     } else if (ddata->jsWrapper.isUndefined() &&
                (ddata->jsEngineId == engine->m_engineId || // We own the QObject
                 ddata->jsEngineId == 0 ||    // No one owns the QObject
@@ -614,7 +618,7 @@ void QObjectWrapper::put(Managed *m, const StringRef name, const ValueRef value)
         return;
 
     QQmlContextData *qmlContext = QV4::QmlContextWrapper::callingContext(v4);
-    if (!setQmlProperty(v4->current, qmlContext, that->m_object, name.getPointer(), QV4::QObjectWrapper::IgnoreRevision, *value)) {
+    if (!setQmlProperty(v4->current, qmlContext, that->m_object, name.getPointer(), QV4::QObjectWrapper::IgnoreRevision, value)) {
         QString error = QLatin1String("Cannot assign to non-existent property \"") +
                         name->toQString() + QLatin1Char('\"');
         v4->current->throwError(error);
@@ -697,13 +701,14 @@ struct QObjectSlotDispatcher : public QtPrivate::QSlotObjectBase
 
             int argCount = argsTypes ? argsTypes[0]:0;
 
-            QV4::FunctionObject *f = This->function.value().asFunctionObject();
-            QV4::ExecutionEngine *v4 = f->internalClass->engine;
+            QV4::ExecutionEngine *v4 = This->function.engine();
+            Q_ASSERT(v4);
+            QV4::Scope scope(v4);
+            QV4::ScopedFunctionObject f(scope, This->function.value());
             QV4::ExecutionContext *ctx = v4->current;
 
-            Scope scope(v4);
             QV4::ScopedCallData callData(scope, argCount);
-            callData->thisObject = This->thisObject.isUndefined() ?  Value::fromObject(v4->globalObject) : This->thisObject.value();
+            callData->thisObject = This->thisObject.isUndefined() ? Value::fromObject(v4->globalObject) : Value::fromReturnedValue(This->thisObject.value());
             for (int ii = 0; ii < argCount; ++ii) {
                 int type = argsTypes[ii + 1];
                 if (type == qMetaTypeId<QVariant>()) {
@@ -752,7 +757,8 @@ struct QObjectSlotDispatcher : public QtPrivate::QSlotObjectBase
                 if (connection->thisObject.isUndefined() == thisObject->isUndefined() &&
                         (connection->thisObject.isUndefined() || __qmljs_strict_equal(connection->thisObject, thisObject))) {
 
-                    QPair<QObject *, int> connectedFunctionData = extractQtMethod(connection->function.value().asFunctionObject());
+                    QV4::ScopedFunctionObject f(scope, connection->function.value());
+                    QPair<QObject *, int> connectedFunctionData = extractQtMethod(f.getPointer());
                     if (connectedFunctionData.first == receiverToDisconnect &&
                         connectedFunctionData.second == slotIndexToDisconnect) {
                         *ret = true;
@@ -798,22 +804,29 @@ ReturnedValue QObjectWrapper::method_connect(SimpleCallContext *ctx)
     if (signalObject->metaObject()->method(signalIndex).methodType() != QMetaMethod::Signal)
         V4THROW_ERROR("Function.prototype.connect: this object is not a signal");
 
-    QV4::QObjectSlotDispatcher *slot = new QV4::QObjectSlotDispatcher;
-    slot->signalIndex = signalIndex;
+    QV4::Scope scope(ctx);
+    QV4::ScopedFunctionObject f(scope);
+    QV4::ScopedValue thisObject (scope, QV4::Encode::undefined());
 
     if (ctx->argumentCount == 1) {
-        slot->function = ctx->arguments[0];
+        f = ctx->arguments[0];
     } else if (ctx->argumentCount >= 2) {
-        slot->thisObject = ctx->arguments[0];
-        slot->function = ctx->arguments[1];
+        thisObject = ctx->arguments[0];
+        f = ctx->arguments[1];
     }
 
-    if (!slot->function.value().asFunctionObject())
+    if (!f)
         V4THROW_ERROR("Function.prototype.connect: target is not a function");
 
-    if (!slot->thisObject.isUndefined() && !slot->thisObject.value().isObject())
+    if (!thisObject->isUndefined() && !thisObject->isObject())
         V4THROW_ERROR("Function.prototype.connect: target this is not an object");
 
+    QV4::QObjectSlotDispatcher *slot = new QV4::QObjectSlotDispatcher;
+    slot->signalIndex = signalIndex;
+
+    slot->thisObject = thisObject;
+    slot->function = f;
+
     QObjectPrivate::connect(signalObject, signalIndex, slot, Qt::AutoConnection);
 
     return Encode::undefined();
@@ -1483,7 +1496,10 @@ void CallArgument::fromValue(int callType, QV8Engine *engine, const QV4::Value &
     if (type != 0) { cleanup(); type = 0; }
 
     if (callType == qMetaTypeId<QJSValue>()) {
-        qjsValuePtr = new (&allocData) QJSValue(new QJSValuePrivate(QV8Engine::getV4(engine), value));
+        QV4::ExecutionEngine *v4 = QV8Engine::getV4(engine);
+        QV4::Scope scope(v4);
+        QV4::ScopedValue v(scope, value);
+        qjsValuePtr = new (&allocData) QJSValue(new QJSValuePrivate(v4, v));
         type = qMetaTypeId<QJSValue>();
     } else if (callType == QMetaType::Int) {
         intValue = quint32(value.toInt32());
@@ -1647,10 +1663,10 @@ QObjectMethod::QObjectMethod(ExecutionContext *scope, QObject *object, int index
     : FunctionObject(scope)
     , m_object(object)
     , m_index(index)
-    , m_qmlGlobal(qmlGlobal)
 {
     vtbl = &static_vtbl;
     subtype = WrappedQtMethod;
+    m_qmlGlobal = qmlGlobal.asReturnedValue();
 }
 
 QV4::ReturnedValue QObjectMethod::method_toString(QV4::ExecutionContext *ctx)
@@ -1719,6 +1735,8 @@ ReturnedValue QObjectMethod::callInternal(CallData *callData)
         return Encode::undefined();
 
     QV8Engine *v8Engine = context->engine->v8Engine;
+    QV4::ExecutionEngine *v4 = QV8Engine::getV4(v8Engine);
+    QV4::Scope scope(v4);
 
     QQmlPropertyData method;
 
@@ -1741,8 +1759,9 @@ ReturnedValue QObjectMethod::callInternal(CallData *callData)
     if (method.isV4Function()) {
         QV4::Value rv = QV4::Value::undefinedValue();
 
-        QQmlV4Function func(callData->argc, callData->args, &rv, m_qmlGlobal.value(),
-                            QmlContextWrapper::getContext(m_qmlGlobal.value()),
+        QV4::ScopedValue qmlGlobal(scope, m_qmlGlobal.value());
+        QQmlV4Function func(callData->argc, callData->args, &rv, qmlGlobal,
+                            QmlContextWrapper::getContext(qmlGlobal),
                             v8Engine);
         QQmlV4Function *funcptr = &func;
 
diff --git a/src/qml/jsruntime/qv4qobjectwrapper_p.h b/src/qml/jsruntime/qv4qobjectwrapper_p.h
index 2fc0767bc8..ea2dccccbc 100644
--- a/src/qml/jsruntime/qv4qobjectwrapper_p.h
+++ b/src/qml/jsruntime/qv4qobjectwrapper_p.h
@@ -88,7 +88,7 @@ struct Q_QML_EXPORT QObjectWrapper : public QV4::Object
     ReturnedValue getQmlProperty(ExecutionContext *ctx, QQmlContextData *qmlContext, String *name, RevisionMode revisionMode, bool *hasProperty = 0, bool includeImports = false);
     static ReturnedValue getQmlProperty(ExecutionContext *ctx, QQmlContextData *qmlContext, QObject *object, String *name, RevisionMode revisionMode, bool *hasProperty = 0);
 
-    static bool setQmlProperty(ExecutionContext *ctx, QQmlContextData *qmlContext, QObject *object, String *name, RevisionMode revisionMode, const Value &value);
+    static bool setQmlProperty(ExecutionContext *ctx, QQmlContextData *qmlContext, QObject *object, String *name, RevisionMode revisionMode, const ValueRef value);
 
     static ReturnedValue wrap(ExecutionEngine *engine, QObject *object);
 
diff --git a/src/qml/jsruntime/qv4scopedvalue_p.h b/src/qml/jsruntime/qv4scopedvalue_p.h
index 09851af091..f11a982b65 100644
--- a/src/qml/jsruntime/qv4scopedvalue_p.h
+++ b/src/qml/jsruntime/qv4scopedvalue_p.h
@@ -439,6 +439,10 @@ struct Referenced {
     Referenced(const Scoped<T> &v)
         : ptr(v.ptr) {}
     Referenced(Safe<T> &v) { ptr = &v; }
+    Referenced(SafeValue &v) {
+        ptr = value_cast<T>(v) ? &v : 0;
+    }
+
     Referenced &operator=(const Referenced &o)
     { *ptr = *o.ptr; return *this; }
     Referenced &operator=(T *t)
@@ -465,7 +469,7 @@ struct Referenced {
     T *getPointer() const {
         return static_cast<T *>(ptr->managed());
     }
-    ReturnedValue asReturnedValue() const { return ptr->val; }
+    ReturnedValue asReturnedValue() const { return ptr ? ptr->val : Value::undefinedValue().asReturnedValue(); }
 
     static Referenced null() { return Referenced(Null); }
     bool isNull() const { return !ptr; }
@@ -643,7 +647,7 @@ PersistentValue::PersistentValue(Returned<T> *obj)
 }
 
 template<typename T>
-inline PersistentValue::PersistentValue(const Scoped<T> &obj)
+inline PersistentValue::PersistentValue(const Referenced<T> obj)
     : d(new PersistentValuePrivate(*obj.ptr))
 {
 }
@@ -655,7 +659,7 @@ inline PersistentValue &PersistentValue::operator=(Returned<T> *obj)
 }
 
 template<typename T>
-inline PersistentValue &PersistentValue::operator=(const Scoped<T> &obj)
+inline PersistentValue &PersistentValue::operator=(const Referenced<T> obj)
 {
     return operator=(*obj.ptr);
 }
diff --git a/src/qml/jsruntime/qv4script.cpp b/src/qml/jsruntime/qv4script.cpp
index 1aa9d80a2d..a6cb40fff8 100644
--- a/src/qml/jsruntime/qv4script.cpp
+++ b/src/qml/jsruntime/qv4script.cpp
@@ -201,7 +201,8 @@ void Script::parse()
             isel->setUseFastLookups(false);
         QV4::CompiledData::CompilationUnit *compilationUnit = isel->compile();
         vmFunction = compilationUnit->linkToEngine(v4);
-        compilationUnitHolder = Value::fromObject(new (v4->memoryManager) CompilationUnitHolder(v4, compilationUnit));
+        ScopedValue holder(valueScope, Value::fromObject(new (v4->memoryManager) CompilationUnitHolder(v4, compilationUnit)));
+        compilationUnitHolder = holder;
     }
 
     if (!vmFunction) {
@@ -256,7 +257,8 @@ ReturnedValue Script::run()
         return result.asReturnedValue();
 
     } else {
-        FunctionObject *f = new (engine->memoryManager) QmlBindingWrapper(scope, vmFunction, qml.value().asObject());
+        ScopedObject qmlObj(valueScope, qml.value());
+        FunctionObject *f = new (engine->memoryManager) QmlBindingWrapper(scope, vmFunction, qmlObj.getPointer());
         ScopedCallData callData(valueScope, 0);
         callData->thisObject = Value::undefinedValue();
         return f->call(callData);
@@ -274,11 +276,13 @@ ReturnedValue Script::qmlBinding()
 {
     if (!parsed)
         parse();
-    QV4::ExecutionEngine *v4 = scope->engine;
-    return Value::fromObject(new (v4->memoryManager) QmlBindingWrapper(scope, vmFunction, qml.value().asObject())).asReturnedValue();
+    ExecutionEngine *v4 = scope->engine;
+    Scope valueScope(v4);
+    ScopedObject qmlObj(valueScope, qml.value());
+    return Value::fromObject(new (v4->memoryManager) QmlBindingWrapper(scope, vmFunction, qmlObj.getPointer())).asReturnedValue();
 }
 
-QV4::ReturnedValue Script::evaluate(ExecutionEngine *engine,  const QString &script, Object *scopeObject)
+QV4::ReturnedValue Script::evaluate(ExecutionEngine *engine,  const QString &script, ObjectRef scopeObject)
 {
     QV4::Scope scope(engine);
     QV4::Script qmlScript(engine, scopeObject, script, QString());
diff --git a/src/qml/jsruntime/qv4script_p.h b/src/qml/jsruntime/qv4script_p.h
index 752cb2ac53..030622cf72 100644
--- a/src/qml/jsruntime/qv4script_p.h
+++ b/src/qml/jsruntime/qv4script_p.h
@@ -73,10 +73,10 @@ struct Q_QML_EXPORT Script {
         : sourceFile(source), line(line), column(column), sourceCode(sourceCode)
         , scope(scope), strictMode(false), inheritContext(false), parsed(false)
         , vmFunction(0), parseAsBinding(false) {}
-    Script(ExecutionEngine *engine, Object *qml, const QString &sourceCode, const QString &source = QString(), int line = 1, int column = 0)
+    Script(ExecutionEngine *engine, ObjectRef qml, const QString &sourceCode, const QString &source = QString(), int line = 1, int column = 0)
         : sourceFile(source), line(line), column(column), sourceCode(sourceCode)
         , scope(engine->rootContext), strictMode(false), inheritContext(true), parsed(false)
-        , qml(Value::fromObject(qml)), vmFunction(0), parseAsBinding(true) {}
+        , qml(qml.asReturnedValue()), vmFunction(0), parseAsBinding(true) {}
     ~Script();
     QString sourceFile;
     int line;
@@ -98,7 +98,7 @@ struct Q_QML_EXPORT Script {
     Function *function();
 
 
-    static ReturnedValue evaluate(ExecutionEngine *engine, const QString &script, Object *scopeObject);
+    static ReturnedValue evaluate(ExecutionEngine *engine, const QString &script, ObjectRef scopeObject);
 };
 
 }
diff --git a/src/qml/jsruntime/qv4value.cpp b/src/qml/jsruntime/qv4value.cpp
index 197b1c2ee5..51f7fba6d3 100644
--- a/src/qml/jsruntime/qv4value.cpp
+++ b/src/qml/jsruntime/qv4value.cpp
@@ -285,18 +285,13 @@ Object *Value::toObject(ExecutionContext *ctx) const
 }
 
 
-PersistentValue::PersistentValue(const Value &val)
-    : d(new PersistentValuePrivate(val))
-{
-}
-
-PersistentValue::PersistentValue(const ScopedValue &val)
-    : d(new PersistentValuePrivate(*val.operator ->()))
+PersistentValue::PersistentValue(const ValueRef val)
+    : d(new PersistentValuePrivate(val.asReturnedValue()))
 {
 }
 
 PersistentValue::PersistentValue(ReturnedValue val)
-    : d(new PersistentValuePrivate(Value::fromReturnedValue(val)))
+    : d(new PersistentValuePrivate(val))
 {
 }
 
@@ -323,33 +318,23 @@ PersistentValue &PersistentValue::operator=(const PersistentValue &other)
     return *this;
 }
 
-PersistentValue &PersistentValue::operator =(const Value &other)
+PersistentValue &PersistentValue::operator =(const ValueRef other)
 {
     if (!d) {
-        d = new PersistentValuePrivate(other);
+        d = new PersistentValuePrivate(other.asReturnedValue());
         return *this;
     }
-    d = d->detach(other);
+    d = d->detach(other.asReturnedValue());
     return *this;
 }
 
-PersistentValue &PersistentValue::operator =(const ScopedValue &other)
-{
-    return operator=(*other.operator ->());
-}
-
-PersistentValue &PersistentValue::operator =(const ValueRef other)
-{
-    return operator=(*other.operator ->());
-}
-
-PersistentValue &PersistentValue::operator =(const ReturnedValue &other)
+PersistentValue &PersistentValue::operator =(ReturnedValue other)
 {
     if (!d) {
-        d = new PersistentValuePrivate(Value::fromReturnedValue(other));
+        d = new PersistentValuePrivate(other);
         return *this;
     }
-    d = d->detach(Value::fromReturnedValue(other));
+    d = d->detach(other);
     return *this;
 }
 
@@ -359,8 +344,8 @@ PersistentValue::~PersistentValue()
         d->deref();
 }
 
-WeakValue::WeakValue(const Value &val)
-    : d(new PersistentValuePrivate(val, /*engine*/0, /*weak*/true))
+WeakValue::WeakValue(const ValueRef val)
+    : d(new PersistentValuePrivate(val.asReturnedValue(), /*engine*/0, /*weak*/true))
 {
 }
 
@@ -372,7 +357,7 @@ WeakValue::WeakValue(const WeakValue &other)
 }
 
 WeakValue::WeakValue(ReturnedValue val)
-    : d(new PersistentValuePrivate(Value::fromReturnedValue(val), /*engine*/0, /*weak*/true))
+    : d(new PersistentValuePrivate(val, /*engine*/0, /*weak*/true))
 {
 }
 
@@ -392,23 +377,23 @@ WeakValue &WeakValue::operator=(const WeakValue &other)
     return *this;
 }
 
-WeakValue &WeakValue::operator =(const Value &other)
+WeakValue &WeakValue::operator =(const ValueRef other)
 {
     if (!d) {
-        d = new PersistentValuePrivate(other, /*engine*/0, /*weak*/true);
+        d = new PersistentValuePrivate(other.asReturnedValue(), /*engine*/0, /*weak*/true);
         return *this;
     }
-    d = d->detach(other, /*weak*/true);
+    d = d->detach(other.asReturnedValue(), /*weak*/true);
     return *this;
 }
 
 WeakValue &WeakValue::operator =(const ReturnedValue &other)
 {
     if (!d) {
-        d = new PersistentValuePrivate(Value::fromReturnedValue(other), /*engine*/0, /*weak*/true);
+        d = new PersistentValuePrivate(other, /*engine*/0, /*weak*/true);
         return *this;
     }
-    d = d->detach(Value::fromReturnedValue(other), /*weak*/true);
+    d = d->detach(other, /*weak*/true);
     return *this;
 }
 
@@ -429,21 +414,27 @@ void WeakValue::markOnce()
     m->mark();
 }
 
-PersistentValuePrivate::PersistentValuePrivate(const Value &v, ExecutionEngine *e, bool weak)
-    : value(v)
-    , refcount(1)
+PersistentValuePrivate::PersistentValuePrivate(ReturnedValue v, ExecutionEngine *e, bool weak)
+    : refcount(1)
+    , weak(weak)
+    , engine(e)
     , prev(0)
     , next(0)
-    , engine(e)
+{
+    value.val = v;
+    init();
+}
+
+void PersistentValuePrivate::init()
 {
     if (!engine) {
-        Managed *m = v.asManaged();
+        Managed *m = value.asManaged();
         if (!m)
             return;
 
         engine = m->engine();
     }
-    if (engine) {
+    if (engine && !prev) {
         PersistentValuePrivate **listRoot = weak ? &engine->memoryManager->m_weakValues : &engine->memoryManager->m_persistentValues;
 
         prev = listRoot;
@@ -479,10 +470,10 @@ void PersistentValuePrivate::deref()
     }
 }
 
-PersistentValuePrivate *PersistentValuePrivate::detach(const QV4::Value &value, bool weak)
+PersistentValuePrivate *PersistentValuePrivate::detach(const QV4::ReturnedValue val, bool weak)
 {
     if (refcount == 1) {
-        this->value = value;
+        value.val = val;
 
         Managed *m = value.asManaged();
         if (!prev) {
@@ -503,6 +494,6 @@ PersistentValuePrivate *PersistentValuePrivate::detach(const QV4::Value &value,
         return this;
     }
     --refcount;
-    return new PersistentValuePrivate(value, engine, weak);
+    return new PersistentValuePrivate(val, engine, weak);
 }
 
diff --git a/src/qml/jsruntime/qv4value_p.h b/src/qml/jsruntime/qv4value_p.h
index ad884b6380..598d30f1f0 100644
--- a/src/qml/jsruntime/qv4value_p.h
+++ b/src/qml/jsruntime/qv4value_p.h
@@ -346,18 +346,20 @@ inline T *Value::as() const { Managed *m = isObject() ? managed() : 0; return m
 
 struct Q_QML_PRIVATE_EXPORT PersistentValuePrivate
 {
-    PersistentValuePrivate(const Value &v, ExecutionEngine *engine = 0, bool weak = false);
+    PersistentValuePrivate(ReturnedValue v, ExecutionEngine *engine = 0, bool weak = false);
     virtual ~PersistentValuePrivate();
     Value value;
     uint refcount;
+    bool weak;
     QV4::ExecutionEngine *engine;
     PersistentValuePrivate **prev;
     PersistentValuePrivate *next;
 
+    void init();
     void removeFromList();
     void ref() { ++refcount; }
     void deref();
-    PersistentValuePrivate *detach(const QV4::Value &value, bool weak = false);
+    PersistentValuePrivate *detach(const ReturnedValue value, bool weak = false);
 
     bool checkEngine(QV4::ExecutionEngine *otherEngine) {
         if (!engine) {
@@ -372,39 +374,36 @@ class Q_QML_EXPORT PersistentValue
 {
 public:
     PersistentValue() : d(0) {}
+    PersistentValue(const PersistentValue &other);
+    PersistentValue &operator=(const PersistentValue &other);
 
-    PersistentValue(const Value &val);
-    PersistentValue(const ScopedValue &val);
+    PersistentValue(const ValueRef val);
     PersistentValue(ReturnedValue val);
     template<typename T>
     PersistentValue(Returned<T> *obj);
     template<typename T>
-    PersistentValue(const Scoped<T> &obj);
-    PersistentValue(const PersistentValue &other);
-    PersistentValue &operator=(const PersistentValue &other);
-    PersistentValue &operator=(const Value &other);
-    PersistentValue &operator=(const ScopedValue &other);
+    PersistentValue(const Referenced<T> obj);
     PersistentValue &operator=(const ValueRef other);
-    PersistentValue &operator =(const ReturnedValue &other);
+    PersistentValue &operator =(ReturnedValue other);
     template<typename T>
     PersistentValue &operator=(Returned<T> *obj);
     template<typename T>
-    PersistentValue &operator=(const Scoped<T> &obj);
+    PersistentValue &operator=(const Referenced<T> obj);
     ~PersistentValue();
 
-    Value value() const {
-        return d ? d->value : Value::undefinedValue();
+    ReturnedValue value() const {
+        return (d ? d->value : Value::undefinedValue()).asReturnedValue();
     }
 
     ExecutionEngine *engine() {
         if (!d)
             return 0;
+        if (d->engine)
+            return d->engine;
         Managed *m = d->value.asManaged();
         return m ? m->engine() : 0;
     }
 
-    operator Value() const { return value(); }
-
     bool isUndefined() const { return !d || d->value.isUndefined(); }
     bool isNullOrUndefined() const { return !d || d->value.isNullOrUndefined(); }
     void clear() {
@@ -420,32 +419,32 @@ class Q_QML_EXPORT WeakValue
 {
 public:
     WeakValue() : d(0) {}
-    WeakValue(const Value &val);
+    WeakValue(const ValueRef val);
     WeakValue(const WeakValue &other);
     WeakValue(ReturnedValue val);
     template<typename T>
     WeakValue(Returned<T> *obj);
     WeakValue &operator=(const WeakValue &other);
-    WeakValue &operator=(const Value &other);
+    WeakValue &operator=(const ValueRef other);
     WeakValue &operator =(const ReturnedValue &other);
     template<typename T>
     WeakValue &operator=(Returned<T> *obj);
 
     ~WeakValue();
 
-    Value value() const {
-        return d ? d->value : Value::undefinedValue();
+    ReturnedValue value() const {
+        return (d ? d->value : Value::undefinedValue()).asReturnedValue();
     }
 
     ExecutionEngine *engine() {
         if (!d)
             return 0;
+        if (d->engine)
+            return d->engine;
         Managed *m = d->value.asManaged();
         return m ? m->engine() : 0;
     }
 
-    operator Value() const { return value(); }
-
     bool isUndefined() const { return !d || d->value.isUndefined(); }
     bool isNullOrUndefined() const { return !d || d->value.isNullOrUndefined(); }
     void clear() {
diff --git a/src/qml/qml/qqmlbinding.cpp b/src/qml/qml/qqmlbinding.cpp
index a5e281dc56..a388178952 100644
--- a/src/qml/qml/qqmlbinding.cpp
+++ b/src/qml/qml/qqmlbinding.cpp
@@ -178,7 +178,7 @@ QQmlBinding::QQmlBinding(const QString &str, QObject *obj,
     v4function = qmlBinding(ctxt, obj, str, url, m_lineNumber);
 }
 
-QQmlBinding::QQmlBinding(const QV4::Value &functionPtr, QObject *obj, QQmlContextData *ctxt,
+QQmlBinding::QQmlBinding(const QV4::ValueRef functionPtr, QObject *obj, QQmlContextData *ctxt,
                          const QString &url, quint16 lineNumber, quint16 columnNumber)
 : QQmlJavaScriptExpression(&QQmlBinding_jsvtable), QQmlAbstractBinding(Binding),
   m_url(url), m_lineNumber(lineNumber), m_columnNumber(columnNumber)
@@ -250,7 +250,8 @@ void QQmlBinding::update(QQmlPropertyPrivate::WriteFlags flags)
 
             bool isUndefined = false;
 
-            QV4::ScopedValue result(scope, QQmlJavaScriptExpression::evaluate(context(), v4function.value(), &isUndefined));
+            QV4::ScopedValue f(scope, v4function.value());
+            QV4::ScopedValue result(scope, QQmlJavaScriptExpression::evaluate(context(), f, &isUndefined));
 
             trace.event("writing binding result");
 
@@ -291,7 +292,8 @@ QVariant QQmlBinding::evaluate()
 
     bool isUndefined = false;
 
-    QV4::ScopedValue result(scope, QQmlJavaScriptExpression::evaluate(context(), v4function.value(), &isUndefined));
+    QV4::ScopedValue f(scope, v4function.value());
+    QV4::ScopedValue result(scope, QQmlJavaScriptExpression::evaluate(context(), f, &isUndefined));
 
     ep->dereferenceScarceResources();
 
diff --git a/src/qml/qml/qqmlbinding_p.h b/src/qml/qml/qqmlbinding_p.h
index ea703e8d38..e872482373 100644
--- a/src/qml/qml/qqmlbinding_p.h
+++ b/src/qml/qml/qqmlbinding_p.h
@@ -84,7 +84,7 @@ public:
     QQmlBinding(const QString &, QObject *, QQmlContextData *);
     QQmlBinding(const QString &, QObject *, QQmlContextData *,
                 const QString &url, quint16 lineNumber, quint16 columnNumber);
-    QQmlBinding(const QV4::Value &, QObject *, QQmlContextData *,
+    QQmlBinding(const QV4::ValueRef, QObject *, QQmlContextData *,
                 const QString &url, quint16 lineNumber, quint16 columnNumber);
 
     void setTarget(const QQmlProperty &);
diff --git a/src/qml/qml/qqmlboundsignal.cpp b/src/qml/qml/qqmlboundsignal.cpp
index 3a0d58d87c..cc2edb7b19 100644
--- a/src/qml/qml/qqmlboundsignal.cpp
+++ b/src/qml/qml/qqmlboundsignal.cpp
@@ -86,7 +86,7 @@ QQmlBoundSignalExpression::QQmlBoundSignalExpression(QObject *target, int index,
     m_expression = expression;
 }
 
-QQmlBoundSignalExpression::QQmlBoundSignalExpression(QObject *target, int index, QQmlContextData *ctxt, QObject *scope, const QV4::PersistentValue &function)
+QQmlBoundSignalExpression::QQmlBoundSignalExpression(QObject *target, int index, QQmlContextData *ctxt, QObject *scope, const QV4::ValueRef &function)
     : QQmlJavaScriptExpression(&QQmlBoundSignalExpression_jsvtable),
       m_v8function(function),
       m_line(-1),
@@ -128,7 +128,9 @@ QString QQmlBoundSignalExpression::expression() const
 {
     if (m_expressionFunctionValid) {
         Q_ASSERT (context() && engine());
-        return m_v8function.value().toQStringNoThrow();
+        QV4::Scope scope(QQmlEnginePrivate::get(engine())->v4engine());
+        QV4::ScopedValue v(scope, m_v8function.value());
+        return v->toQStringNoThrow();
     } else {
         return m_expression;
     }
@@ -144,6 +146,7 @@ void QQmlBoundSignalExpression::evaluate(void **a)
         return;
 
     QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine());
+    QV4::Scope scope(ep->v4engine());
 
     ep->referenceScarceResources(); // "hold" scarce resources in memory during evaluation.
     {
@@ -181,7 +184,7 @@ void QQmlBoundSignalExpression::evaluate(void **a)
             m_v8function = evalFunction(context(), scopeObject(), expression,
                                         m_fileName, m_line, &m_v8qmlscope);
 
-            if (m_v8function.isUndefined() || m_v8function.value().isNull()) {
+            if (m_v8function.isNullOrUndefined()) {
                 ep->dereferenceScarceResources();
                 return; // could not evaluate function.  Not valid.
             }
@@ -223,7 +226,8 @@ void QQmlBoundSignalExpression::evaluate(void **a)
             }
         }
 
-        QQmlJavaScriptExpression::evaluate(context(), m_v8function.value(), argCount, args, 0);
+        QV4::ScopedValue f(scope, m_v8function.value());
+        QQmlJavaScriptExpression::evaluate(context(), f, argCount, args, 0);
     }
     ep->dereferenceScarceResources(); // "release" scarce resources if top-level expression evaluation is complete.
 }
diff --git a/src/qml/qml/qqmlboundsignal_p.h b/src/qml/qml/qqmlboundsignal_p.h
index 86e3dc20ea..feb79d5484 100644
--- a/src/qml/qml/qqmlboundsignal_p.h
+++ b/src/qml/qml/qqmlboundsignal_p.h
@@ -76,7 +76,7 @@ public:
                               const QString &parameterString = QString());
 
     QQmlBoundSignalExpression(QObject *target, int index,
-                              QQmlContextData *ctxt, QObject *scope, const QV4::PersistentValue &function);
+                              QQmlContextData *ctxt, QObject *scope, const QV4::ValueRef &function);
 
 
     // "inherited" from QQmlJavaScriptExpression.
diff --git a/src/qml/qml/qqmlcomponent.cpp b/src/qml/qml/qqmlcomponent.cpp
index cf3493a590..cfda595438 100644
--- a/src/qml/qml/qqmlcomponent.cpp
+++ b/src/qml/qml/qqmlcomponent.cpp
@@ -1123,7 +1123,7 @@ public:
     QV8Engine *v8;
     QPointer<QObject> parent;
     QV4::Value valuemap;
-    QV4::Value qmlGlobal;
+    QV4::SafeValue qmlGlobal;
     QV4::Value m_statusChanged;
 protected:
     virtual void statusChanged(Status);
@@ -1244,7 +1244,8 @@ void QQmlComponent::createObject(QQmlV4Function *args)
 
     if (!valuemap.isUndefined()) {
         QQmlComponentExtension *e = componentExtension(v8engine);
-        QV4::ScopedValue f(scope, QV4::Script::evaluate(v4engine, QString::fromLatin1(INITIALPROPERTIES_SOURCE), args->qmlGlobal().asObject()));
+        QV4::ScopedObject qmlglobal(scope, args->qmlGlobal());
+        QV4::ScopedValue f(scope, QV4::Script::evaluate(v4engine, QString::fromLatin1(INITIALPROPERTIES_SOURCE), qmlglobal));
         Q_ASSERT(f->asFunctionObject());
         QV4::ScopedCallData callData(scope, 2);
         callData->thisObject = QV4::Value::fromObject(v4engine->globalObject);
@@ -1329,9 +1330,11 @@ void QQmlComponent::incubateObject(QQmlV4Function *args)
     Q_ASSERT(d->engine);
     Q_UNUSED(d);
     Q_ASSERT(args);
+    QV4::ExecutionEngine *v4 = QV8Engine::getV4(args->engine());
+    QV4::Scope scope(v4);
 
     QObject *parent = 0;
-    QV4::Value valuemap = QV4::Value::undefinedValue();
+    QV4::ScopedValue valuemap(scope, QV4::Value::undefinedValue());
     QQmlIncubator::IncubationMode mode = QQmlIncubator::Asynchronous;
 
     if (args->length() >= 1) {
@@ -1340,9 +1343,9 @@ void QQmlComponent::incubateObject(QQmlV4Function *args)
     }
 
     if (args->length() >= 2) {
-        QV4::Value v = (*args)[1];
-        if (v.isNull()) {
-        } else if (!v.asObject() || v.asArrayObject()) {
+        QV4::ScopedValue v(scope, (*args)[1]);
+        if (v->isNull()) {
+        } else if (!v->asObject() || v->asArrayObject()) {
             qmlInfo(this) << tr("createObject: value is not an object");
             args->setReturnValue(QV4::Value::nullValue());
             return;
@@ -1361,27 +1364,27 @@ void QQmlComponent::incubateObject(QQmlV4Function *args)
 
     QQmlComponentExtension *e = componentExtension(args->engine());
 
-    QV4::ExecutionEngine *v4 = QV8Engine::getV4(args->engine());
-    QmlIncubatorObject *r = new (v4->memoryManager) QmlIncubatorObject(args->engine(), mode);
-    r->setPrototype(e->incubationProto.value().asObject());
+    QV4::Scoped<QmlIncubatorObject> r(scope, new (v4->memoryManager) QmlIncubatorObject(args->engine(), mode));
+    QV4::ScopedObject p(scope, e->incubationProto.value());
+    r->setPrototype(p.getPointer());
 
-    if (!valuemap.isUndefined()) {
+    if (!valuemap->isUndefined()) {
         r->valuemap = valuemap;
         r->qmlGlobal = args->qmlGlobal();
     }
     r->parent = parent;
 
-    create(*r, creationContext());
+    create(*r.getPointer(), creationContext());
 
     if (r->status() == QQmlIncubator::Null) {
         args->setReturnValue(QV4::Value::nullValue());
     } else {
-        args->setReturnValue(QV4::Value::fromObject(r));
+        args->setReturnValue(r.asValue());
     }
 }
 
 // XXX used by QSGLoader
-void QQmlComponentPrivate::initializeObjectWithInitialProperties(const QV4::Value &qmlGlobal, const QV4::Value &valuemap, QObject *toCreate)
+void QQmlComponentPrivate::initializeObjectWithInitialProperties(const QV4::ValueRef qmlGlobal, const QV4::Value &valuemap, QObject *toCreate)
 {
     QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine);
     QV8Engine *v8engine = ep->v8engine();
@@ -1393,8 +1396,9 @@ void QQmlComponentPrivate::initializeObjectWithInitialProperties(const QV4::Valu
 
     if (!valuemap.isUndefined()) {
         QQmlComponentExtension *e = componentExtension(v8engine);
+        QV4::ScopedObject qmlGlobalObj(scope, qmlGlobal);
         QV4::Scoped<QV4::FunctionObject>  f(scope, QV4::Script::evaluate(QV8Engine::getV4(v8engine),
-                                                                    QString::fromLatin1(INITIALPROPERTIES_SOURCE), qmlGlobal.asObject()));
+                                                                    QString::fromLatin1(INITIALPROPERTIES_SOURCE), qmlGlobalObj));
         QV4::ScopedCallData callData(scope, 2);
         callData->thisObject = QV4::Value::fromObject(v4engine->globalObject);
         callData->args[0] = object;
@@ -1490,7 +1494,7 @@ void QmlIncubatorObject::setInitialState(QObject *o)
         QV4::ExecutionEngine *v4 = QV8Engine::getV4(v8);
         QV4::Scope scope(v4);
 
-        QV4::Scoped<QV4::FunctionObject> f(scope, QV4::Script::evaluate(v4, QString::fromLatin1(INITIALPROPERTIES_SOURCE), qmlGlobal.asObject()));
+        QV4::Scoped<QV4::FunctionObject> f(scope, QV4::Script::evaluate(v4, QString::fromLatin1(INITIALPROPERTIES_SOURCE), qmlGlobal));
         QV4::ScopedCallData callData(scope, 2);
         callData->thisObject = QV4::Value::fromObject(v4->globalObject);
         callData->args[0] = QV4::Value::fromReturnedValue(QV4::QObjectWrapper::wrap(v4, o));
diff --git a/src/qml/qml/qqmlcomponent_p.h b/src/qml/qml/qqmlcomponent_p.h
index 08e4dcea7d..f2f81c8ab2 100644
--- a/src/qml/qml/qqmlcomponent_p.h
+++ b/src/qml/qml/qqmlcomponent_p.h
@@ -91,7 +91,7 @@ public:
 
     QObject *beginCreate(QQmlContextData *);
     void completeCreate();
-    void initializeObjectWithInitialProperties(const QV4::Value &qmlGlobal, const QV4::Value &valuemap, QObject *toCreate);
+    void initializeObjectWithInitialProperties(const QV4::ValueRef qmlGlobal, const QV4::Value &valuemap, QObject *toCreate);
 
     QQmlTypeData *typeData;
     virtual void typeDataReady(QQmlTypeData *);
diff --git a/src/qml/qml/qqmlcontextwrapper.cpp b/src/qml/qml/qqmlcontextwrapper.cpp
index 425c19a090..46ff821fff 100644
--- a/src/qml/qml/qqmlcontextwrapper.cpp
+++ b/src/qml/qml/qqmlcontextwrapper.cpp
@@ -188,7 +188,7 @@ ReturnedValue QmlContextWrapper::get(Managed *m, const StringRef name, bool *has
             if (r.scriptIndex != -1) {
                 int index = r.scriptIndex;
                 if (index < context->importedScripts.count())
-                    return context->importedScripts.at(index).value().asReturnedValue();
+                    return context->importedScripts.at(index).value();
                 else
                     return QV4::Value::undefinedValue().asReturnedValue();
             } else if (r.type) {
@@ -318,13 +318,13 @@ void QmlContextWrapper::put(Managed *m, const StringRef name, const ValueRef val
 
         // Search scope object
         if (scopeObject &&
-            QV4::QObjectWrapper::setQmlProperty(v4->current, context, scopeObject, name.getPointer(), QV4::QObjectWrapper::CheckRevision, *value))
+            QV4::QObjectWrapper::setQmlProperty(v4->current, context, scopeObject, name.getPointer(), QV4::QObjectWrapper::CheckRevision, value))
             return;
         scopeObject = 0;
 
         // Search context object
         if (context->contextObject &&
-            QV4::QObjectWrapper::setQmlProperty(v4->current, context, context->contextObject, name.getPointer(), QV4::QObjectWrapper::CheckRevision, *value))
+            QV4::QObjectWrapper::setQmlProperty(v4->current, context, context->contextObject, name.getPointer(), QV4::QObjectWrapper::CheckRevision, value))
             return;
 
         context = context->parent;
diff --git a/src/qml/qml/qqmlengine.cpp b/src/qml/qml/qqmlengine.cpp
index 2e77d8257b..2f873936e3 100644
--- a/src/qml/qml/qqmlengine.cpp
+++ b/src/qml/qml/qqmlengine.cpp
@@ -1654,7 +1654,7 @@ void QQmlData::destroyed(QObject *object)
         delete extendedData;
 
     // Dispose the handle.
-    jsWrapper = QV4::Value::undefinedValue();
+    jsWrapper.clear();
 
     if (ownMemory)
         delete this;
diff --git a/src/qml/qml/qqmlexpression.cpp b/src/qml/qml/qqmlexpression.cpp
index 76214c17a4..cdb5813221 100644
--- a/src/qml/qml/qqmlexpression.cpp
+++ b/src/qml/qml/qqmlexpression.cpp
@@ -262,12 +262,17 @@ void QQmlExpression::setExpression(const QString &expression)
 // Must be called with a valid handle scope
 QV4::ReturnedValue QQmlExpressionPrivate::v4value(bool *isUndefined)
 {
+    Q_Q(QQmlExpression);
+
     if (!expressionFunctionValid) {
         function = qmlBinding(context(), scopeObject(), expression, url, line, &qmlscope);
         expressionFunctionValid = true;
     }
 
-    return evaluate(context(), function.value(), isUndefined);
+    QV4::ExecutionEngine *v4 = QQmlEnginePrivate::get(q->engine())->v4engine();
+    QV4::Scope scope(v4);
+    QV4::ScopedValue f(scope, function.value());
+    return evaluate(context(), f, isUndefined);
 }
 
 QVariant QQmlExpressionPrivate::value(bool *isUndefined)
diff --git a/src/qml/qml/qqmljavascriptexpression.cpp b/src/qml/qml/qqmljavascriptexpression.cpp
index b1184729d0..e08e8eebb7 100644
--- a/src/qml/qml/qqmljavascriptexpression.cpp
+++ b/src/qml/qml/qqmljavascriptexpression.cpp
@@ -321,7 +321,7 @@ void QQmlJavaScriptExpression::exceptionToError(const QV4::Exception &e, QQmlErr
     }
 }
 
-QV4::PersistentValue
+QV4::ReturnedValue
 QQmlJavaScriptExpression::evalFunction(QQmlContextData *ctxt, QObject *scopeObject,
                                        const QString &code, const QString &filename, quint16 line,
                                        QV4::PersistentValue *qmlscope)
@@ -333,8 +333,8 @@ QQmlJavaScriptExpression::evalFunction(QQmlContextData *ctxt, QObject *scopeObje
     QV4::ExecutionContext *ctx = v4->current;
     QV4::Scope scope(v4);
 
-    QV4::Scoped<QV4::Object> qmlScopeObject(scope, QV4::QmlContextWrapper::qmlScope(ep->v8engine(), ctxt, scopeObject));
-    QV4::Script script(v4, qmlScopeObject.getPointer(), code, filename, line);
+    QV4::ScopedObject qmlScopeObject(scope, QV4::QmlContextWrapper::qmlScope(ep->v8engine(), ctxt, scopeObject));
+    QV4::Script script(v4, qmlScopeObject, code, filename, line);
     QV4::ScopedValue result(scope);
     try {
         script.parse();
@@ -351,14 +351,14 @@ QQmlJavaScriptExpression::evalFunction(QQmlContextData *ctxt, QObject *scopeObje
             error.setUrl(QUrl::fromLocalFile(filename));
         error.setObject(scopeObject);
         ep->warning(error);
-        return QV4::PersistentValue();
+        return QV4::Encode::undefined();
     }
     if (qmlscope)
-        *qmlscope = qmlScopeObject.asValue();
+        *qmlscope = qmlScopeObject;
     return result.asReturnedValue();
 }
 
-QV4::PersistentValue QQmlJavaScriptExpression::qmlBinding(QQmlContextData *ctxt, QObject *qmlScope,
+QV4::ReturnedValue QQmlJavaScriptExpression::qmlBinding(QQmlContextData *ctxt, QObject *qmlScope,
                                                        const QString &code, const QString &filename, quint16 line,
                                                        QV4::PersistentValue *qmlscope)
 {
@@ -369,8 +369,8 @@ QV4::PersistentValue QQmlJavaScriptExpression::qmlBinding(QQmlContextData *ctxt,
     QV4::ExecutionContext *ctx = v4->current;
     QV4::Scope scope(v4);
 
-    QV4::ScopedValue qmlScopeObject(scope, QV4::QmlContextWrapper::qmlScope(ep->v8engine(), ctxt, qmlScope));
-    QV4::Script script(v4, qmlScopeObject->asObject(), code, filename, line);
+    QV4::ScopedObject qmlScopeObject(scope, QV4::QmlContextWrapper::qmlScope(ep->v8engine(), ctxt, qmlScope));
+    QV4::Script script(v4, qmlScopeObject, code, filename, line);
     QV4::ScopedValue result(scope);
     try {
         script.parse();
@@ -387,7 +387,7 @@ QV4::PersistentValue QQmlJavaScriptExpression::qmlBinding(QQmlContextData *ctxt,
             error.setUrl(QUrl::fromLocalFile(filename));
         error.setObject(qmlScope);
         ep->warning(error);
-        return QV4::PersistentValue();
+        return QV4::Encode::undefined();
     }
     if (qmlscope)
         *qmlscope = qmlScopeObject;
diff --git a/src/qml/qml/qqmljavascriptexpression_p.h b/src/qml/qml/qqmljavascriptexpression_p.h
index f08b3af6cf..c13e191216 100644
--- a/src/qml/qml/qqmljavascriptexpression_p.h
+++ b/src/qml/qml/qqmljavascriptexpression_p.h
@@ -146,12 +146,12 @@ public:
     QQmlDelayedError *delayedError();
 
     static void exceptionToError(const QV4::Exception &e, QQmlError &);
-    static QV4::PersistentValue evalFunction(QQmlContextData *ctxt, QObject *scope,
+    static QV4::ReturnedValue evalFunction(QQmlContextData *ctxt, QObject *scope,
                                                      const QString &code, const QString &filename,
                                                      quint16 line,
                                                      QV4::PersistentValue *qmlscope = 0);
     // doesn't require rewriting the expression
-    static QV4::PersistentValue qmlBinding(QQmlContextData *ctxt, QObject *scope,
+    static QV4::ReturnedValue qmlBinding(QQmlContextData *ctxt, QObject *scope,
                                         const QString &code,
                                         const QString &filename, quint16 line,
                                         QV4::PersistentValue *qmlscope = 0);
diff --git a/src/qml/qml/qqmllocale.cpp b/src/qml/qml/qqmllocale.cpp
index c3c7d0282d..db949467d1 100644
--- a/src/qml/qml/qqmllocale.cpp
+++ b/src/qml/qml/qqmllocale.cpp
@@ -835,11 +835,13 @@ QV4::ReturnedValue QQmlLocale::locale(QV8Engine *v8engine, const QString &locale
 {
     QV8LocaleDataDeletable *d = localeV8Data(v8engine);
     QV4::ExecutionEngine *engine = QV8Engine::getV4(v8engine);
-    QQmlLocaleData *wrapper = new (engine->memoryManager) QQmlLocaleData(engine);
+    QV4::Scope scope(engine);
+    QV4::Scoped<QQmlLocaleData> wrapper(scope, new (engine->memoryManager) QQmlLocaleData(engine));
     if (!locale.isEmpty())
         wrapper->locale = QLocale(locale);
-    wrapper->setPrototype(d->prototype.value().asObject());
-    return QV4::Value::fromObject(wrapper).asReturnedValue();
+    QV4::ScopedObject p(scope, d->prototype.value());
+    wrapper->setPrototype(p.getPointer());
+    return wrapper.asReturnedValue();
 }
 
 void QQmlLocale::registerStringLocaleCompare(QV4::ExecutionEngine *engine)
diff --git a/src/qml/qml/qqmlobjectcreator.cpp b/src/qml/qml/qqmlobjectcreator.cpp
index 601f4dbba0..2f4e782069 100644
--- a/src/qml/qml/qqmlobjectcreator.cpp
+++ b/src/qml/qml/qqmlobjectcreator.cpp
@@ -1080,7 +1080,9 @@ bool QmlObjectCreator::setPropertyValue(QQmlPropertyData *property, int bindingI
 
     if (binding->type == QV4::CompiledData::Binding::Type_Script) {
         QV4::Function *runtimeFunction = jsUnit->runtimeFunctions[binding->value.compiledScriptIndex];
-        QV4::Value function = QV4::Value::fromObject(QV4::FunctionObject::creatScriptFunction(_qmlContext, runtimeFunction));
+
+        QV4::Scope scope(_qmlContext);
+        QV4::ScopedFunctionObject function(scope, QV4::FunctionObject::creatScriptFunction(_qmlContext, runtimeFunction));
 
         if (binding->flags & QV4::CompiledData::Binding::IsSignalHandlerExpression) {
             int signalIndex = _propertyCache->methodIndexToSignalIndex(property->coreIndex);
@@ -1194,6 +1196,8 @@ bool QmlObjectCreator::setPropertyValue(QQmlPropertyData *property, int bindingI
 
 void QmlObjectCreator::setupFunctions()
 {
+    QV4::Scope scope(_qmlContext);
+    QV4::ScopedValue function(scope);
     QQmlVMEMetaObject *vme = QQmlVMEMetaObject::get(_qobject);
 
     const quint32 *functionIdx = _compiledObject->functionOffsetTable();
@@ -1205,8 +1209,8 @@ void QmlObjectCreator::setupFunctions()
         if (!property->isVMEFunction())
             continue;
 
-        QV4::FunctionObject *function = QV4::FunctionObject::creatScriptFunction(_qmlContext, runtimeFunction);
-        vme->setVmeMethod(property->coreIndex, QV4::Value::fromObject(function));
+        function = QV4::FunctionObject::creatScriptFunction(_qmlContext, runtimeFunction);
+        vme->setVmeMethod(property->coreIndex, function);
     }
 }
 
diff --git a/src/qml/qml/qqmlproperty.cpp b/src/qml/qml/qqmlproperty.cpp
index f821687f63..bcecda9c57 100644
--- a/src/qml/qml/qqmlproperty.cpp
+++ b/src/qml/qml/qqmlproperty.cpp
@@ -1460,7 +1460,7 @@ bool QQmlPropertyPrivate::writeBinding(QObject *object,
                                                const QQmlPropertyData &core,
                                                QQmlContextData *context,
                                                QQmlJavaScriptExpression *expression,
-                                               const QV4::Value &result, bool isUndefined,
+                                               const QV4::ValueRef result, bool isUndefined,
                                                WriteFlags flags)
 {
     Q_ASSERT(object);
@@ -1482,22 +1482,22 @@ bool QQmlPropertyPrivate::writeBinding(QObject *object,
     if (!isUndefined && !core.isValueTypeVirtual()) {
         switch (core.propType) {
         case QMetaType::Int:
-            if (result.isInteger())
-                QUICK_STORE(int, result.integerValue())
-            else if (result.isNumber())
-                QUICK_STORE(int, qRound(result.doubleValue()))
+            if (result->isInteger())
+                QUICK_STORE(int, result->integerValue())
+            else if (result->isNumber())
+                QUICK_STORE(int, qRound(result->doubleValue()))
             break;
         case QMetaType::Double:
-            if (result.isNumber())
-                QUICK_STORE(double, result.asDouble())
+            if (result->isNumber())
+                QUICK_STORE(double, result->asDouble())
             break;
         case QMetaType::Float:
-            if (result.isNumber())
-                QUICK_STORE(float, result.asDouble())
+            if (result->isNumber())
+                QUICK_STORE(float, result->asDouble())
             break;
         case QMetaType::QString:
-            if (result.isString())
-                QUICK_STORE(QString, result.toQStringNoThrow())
+            if (result->isString())
+                QUICK_STORE(QString, result->toQStringNoThrow())
             break;
         default:
             break;
@@ -1514,19 +1514,19 @@ bool QQmlPropertyPrivate::writeBinding(QObject *object,
 
     if (isUndefined) {
     } else if (core.isQList()) {
-        value = v8engine->toVariant(result, qMetaTypeId<QList<QObject *> >());
-    } else if (result.isNull() && core.isQObject()) {
+        value = v8engine->toVariant(*result, qMetaTypeId<QList<QObject *> >());
+    } else if (result->isNull() && core.isQObject()) {
         value = QVariant::fromValue((QObject *)0);
     } else if (core.propType == qMetaTypeId<QList<QUrl> >()) {
-        value = resolvedUrlSequence(v8engine->toVariant(result, qMetaTypeId<QList<QUrl> >()), context);
+        value = resolvedUrlSequence(v8engine->toVariant(*result, qMetaTypeId<QList<QUrl> >()), context);
     } else if (!isVarProperty && type != qMetaTypeId<QJSValue>()) {
-        value = v8engine->toVariant(result, type);
+        value = v8engine->toVariant(*result, type);
     }
 
     if (expression->hasError()) {
         return false;
     } else if (isVarProperty) {
-        QV4::FunctionObject *f = result.asFunctionObject();
+        QV4::FunctionObject *f = result->asFunctionObject();
         if (f && f->bindingKeyFlag) {
             // we explicitly disallow this case to avoid confusion.  Users can still store one
             // in an array in a var property if they need to, but the common case is user error.
@@ -1537,14 +1537,14 @@ bool QQmlPropertyPrivate::writeBinding(QObject *object,
 
         QQmlVMEMetaObject *vmemo = QQmlVMEMetaObject::get(object);
         Q_ASSERT(vmemo);
-        vmemo->setVMEProperty(core.coreIndex, result);
+        vmemo->setVMEProperty(core.coreIndex, *result);
     } else if (isUndefined && core.isResettable()) {
         void *args[] = { 0 };
         QMetaObject::metacall(object, QMetaObject::ResetProperty, core.coreIndex, args);
     } else if (isUndefined && type == qMetaTypeId<QVariant>()) {
         writeValueProperty(object, core, QVariant(), context, flags);
     } else if (type == qMetaTypeId<QJSValue>()) {
-        QV4::FunctionObject *f = result.asFunctionObject();
+        QV4::FunctionObject *f = result->asFunctionObject();
         if (f && f->bindingKeyFlag) {
             expression->delayedError()->setErrorDescription(QLatin1String("Invalid use of Qt.binding() in a binding declaration."));
             expression->delayedError()->setErrorObject(object);
@@ -1562,7 +1562,7 @@ bool QQmlPropertyPrivate::writeBinding(QObject *object,
         expression->delayedError()->setErrorDescription(errorStr);
         expression->delayedError()->setErrorObject(object);
         return false;
-    } else if (QV4::FunctionObject *f = result.asFunctionObject()) {
+    } else if (QV4::FunctionObject *f = result->asFunctionObject()) {
         if (f->bindingKeyFlag)
             expression->delayedError()->setErrorDescription(QLatin1String("Invalid use of Qt.binding() in a binding declaration."));
         else
diff --git a/src/qml/qml/qqmlproperty_p.h b/src/qml/qml/qqmlproperty_p.h
index 9af091ad46..ce15061ba0 100644
--- a/src/qml/qml/qqmlproperty_p.h
+++ b/src/qml/qml/qqmlproperty_p.h
@@ -148,7 +148,7 @@ public:
     static bool writeBinding(QObject *, const QQmlPropertyData &,
                              QQmlContextData *context,
                              QQmlJavaScriptExpression *expression,
-                             const QV4::Value &result, bool isUndefined,
+                             const QV4::ValueRef result, bool isUndefined,
                              WriteFlags flags);
     static int valueTypeCoreIndex(const QQmlProperty &that);
     static int bindingIndex(const QQmlProperty &that);
diff --git a/src/qml/qml/qqmltypewrapper.cpp b/src/qml/qml/qqmltypewrapper.cpp
index d5c0ed058c..13dad049c8 100644
--- a/src/qml/qml/qqmltypewrapper.cpp
+++ b/src/qml/qml/qqmltypewrapper.cpp
@@ -160,9 +160,8 @@ ReturnedValue QmlTypeWrapper::get(Managed *m, const StringRef name, bool *hasPro
                 // check for property.
                 return QV4::QObjectWrapper::getQmlProperty(v4->current, context, qobjectSingleton, name.getPointer(), QV4::QObjectWrapper::IgnoreRevision, hasProperty);
             } else if (!siinfo->scriptApi(e).isUndefined()) {
-                QV4::ExecutionEngine *engine = QV8Engine::getV4(v8engine);
                 // NOTE: if used in a binding, changes will not trigger re-evaluation since non-NOTIFYable.
-                QV4::Scoped<Object> o(scope, QJSValuePrivate::get(siinfo->scriptApi(e))->getValue(engine));
+                QV4::ScopedObject o(scope, QJSValuePrivate::get(siinfo->scriptApi(e))->getValue(v4));
                 if (!!o)
                     return o->get(name);
             }
@@ -203,7 +202,7 @@ ReturnedValue QmlTypeWrapper::get(Managed *m, const StringRef name, bool *hasPro
             } else if (r.scriptIndex != -1) {
                 int index = r.scriptIndex;
                 if (index < context->importedScripts.count())
-                    return context->importedScripts.at(index).value().asReturnedValue();
+                    return context->importedScripts.at(index).value();
             } else if (r.importNamespace) {
                 return create(w->v8, object, context->imports, r.importNamespace);
             }
@@ -231,6 +230,7 @@ void QmlTypeWrapper::put(Managed *m, const StringRef name, const ValueRef value)
     if (!w)
         v4->current->throwTypeError();
 
+    QV4::Scope scope(v4);
     QV8Engine *v8engine = v4->v8Engine;
     QQmlContextData *context = v8engine->callingContext();
 
@@ -239,7 +239,7 @@ void QmlTypeWrapper::put(Managed *m, const StringRef name, const ValueRef value)
         QObject *object = w->object;
         QObject *ao = qmlAttachedPropertiesObjectById(type->attachedPropertiesId(), object);
         if (ao) 
-            QV4::QObjectWrapper::setQmlProperty(v4->current, context, ao, name.getPointer(), QV4::QObjectWrapper::IgnoreRevision, *value);
+            QV4::QObjectWrapper::setQmlProperty(v4->current, context, ao, name.getPointer(), QV4::QObjectWrapper::IgnoreRevision, value);
     } else if (type && type->isSingleton()) {
         QQmlEngine *e = v8engine->engine();
         QQmlType::SingletonInstanceInfo *siinfo = type->singletonInstanceInfo();
@@ -247,9 +247,9 @@ void QmlTypeWrapper::put(Managed *m, const StringRef name, const ValueRef value)
 
         QObject *qobjectSingleton = siinfo->qobjectApi(e);
         if (qobjectSingleton) {
-            QV4::QObjectWrapper::setQmlProperty(v4->current, context, qobjectSingleton, name.getPointer(), QV4::QObjectWrapper::IgnoreRevision, *value);
+            QV4::QObjectWrapper::setQmlProperty(v4->current, context, qobjectSingleton, name.getPointer(), QV4::QObjectWrapper::IgnoreRevision, value);
         } else if (!siinfo->scriptApi(e).isUndefined()) {
-            QV4::Object *apiprivate = QJSValuePrivate::get(siinfo->scriptApi(e))->value.asObject();
+            QV4::ScopedObject apiprivate(scope, QJSValuePrivate::get(siinfo->scriptApi(e))->value);
             if (!apiprivate) {
                 QString error = QLatin1String("Cannot assign to read-only property \"") + name->toQString() + QLatin1Char('\"');
                 v4->current->throwError(error);
diff --git a/src/qml/qml/qqmlvaluetypewrapper.cpp b/src/qml/qml/qqmlvaluetypewrapper.cpp
index b27d99793f..f1d2f3a85c 100644
--- a/src/qml/qml/qqmlvaluetypewrapper.cpp
+++ b/src/qml/qml/qqmlvaluetypewrapper.cpp
@@ -372,7 +372,7 @@ void QmlValueTypeWrapper::put(Managed *m, const StringRef name, const ValueRef v
 
             QV4::ExecutionEngine::StackFrame frame = v4->currentStackFrame();
 
-            newBinding = new QQmlBinding(*value, reference->object, context,
+            newBinding = new QQmlBinding(value, reference->object, context,
                                          frame.source, qmlSourceCoordinate(frame.line), qmlSourceCoordinate(frame.column));
             newBinding->setTarget(reference->object, cacheData, context);
             newBinding->setEvaluateFlags(newBinding->evaluateFlags() |
diff --git a/src/qml/qml/qqmlvme.cpp b/src/qml/qml/qqmlvme.cpp
index 1a6577d7ad..3b88e148c7 100644
--- a/src/qml/qml/qqmlvme.cpp
+++ b/src/qml/qml/qqmlvme.cpp
@@ -1087,7 +1087,7 @@ void QQmlScriptData::initialize(QQmlEngine *engine)
 
     // If compilation throws an error, a surrounding catch will record it.
     // pass 0 as the QML object, we set it later before calling run()
-    QV4::Script *program = new QV4::Script(v4, 0, m_programSource, urlString, 1);
+    QV4::Script *program = new QV4::Script(v4, QV4::ObjectRef::null(), m_programSource, urlString, 1);
     try {
         program->parse();
     } catch (QV4::Exception &) {
diff --git a/src/qml/qml/qqmlvmemetaobject.cpp b/src/qml/qml/qqmlvmemetaobject.cpp
index d70df5175b..18f3dff39d 100644
--- a/src/qml/qml/qqmlvmemetaobject.cpp
+++ b/src/qml/qml/qqmlvmemetaobject.cpp
@@ -76,7 +76,7 @@ void QQmlVMEVariantQObjectPtr::objectDestroyed(QObject *)
             QV4::ExecutionEngine *v4 = m_target->varProperties.engine();
             if (v4) {
                 QV4::Scope scope(v4);
-                QV4::ScopedArrayObject a(scope, m_target->varProperties.value().asArrayObject());
+                QV4::ScopedArrayObject a(scope, m_target->varProperties.value());
                 if (a)
                     a->putIndexed(m_index - m_target->firstVarPropertyIndex, QV4::ScopedValue(scope, QV4::Value::nullValue()));
             }
@@ -989,24 +989,30 @@ QV4::ReturnedValue QQmlVMEMetaObject::method(int index)
                                                                ctxt->urlString, data->lineNumber);
     }
 
-    return v8methods[index].value().asReturnedValue();
+    return v8methods[index].value();
 }
 
 QV4::ReturnedValue QQmlVMEMetaObject::readVarProperty(int id)
 {
     Q_ASSERT(id >= firstVarPropertyIndex);
 
-    if (ensureVarPropertiesAllocated())
-        return varProperties.value().asObject()->getIndexed(id - firstVarPropertyIndex);
+    if (ensureVarPropertiesAllocated()) {
+        QV4::Scope scope(QQmlEnginePrivate::get(ctxt->engine)->v4engine());
+        QV4::ScopedObject o(scope, varProperties.value());
+        return o->getIndexed(id - firstVarPropertyIndex);
+    }
     return QV4::Value::undefinedValue().asReturnedValue();
 }
 
 QVariant QQmlVMEMetaObject::readPropertyAsVariant(int id)
 {
     if (id >= firstVarPropertyIndex) {
-        if (ensureVarPropertiesAllocated())
+        if (ensureVarPropertiesAllocated()) {
+            QV4::Scope scope(QQmlEnginePrivate::get(ctxt->engine)->v4engine());
+            QV4::ScopedObject o(scope, varProperties.value());
             return QQmlEnginePrivate::get(ctxt->engine)->v8engine()->toVariant(
-                        QV4::Value::fromReturnedValue(varProperties.value().asObject()->getIndexed(id - firstVarPropertyIndex)), -1);
+                        QV4::Value::fromReturnedValue(o->getIndexed(id - firstVarPropertyIndex)), -1);
+        }
         return QVariant();
     } else {
         if (data[id].dataType() == QMetaType::QObjectStar) {
@@ -1026,7 +1032,8 @@ void QQmlVMEMetaObject::writeVarProperty(int id, const QV4::Value &value)
     QV4::Scope scope(varProperties.engine());
     // Importantly, if the current value is a scarce resource, we need to ensure that it
     // gets automatically released by the engine if no other references to it exist.
-    QV4::Scoped<QV4::VariantObject> oldv(scope, varProperties.value().asObject()->getIndexed(id - firstVarPropertyIndex));
+    QV4::ScopedObject vp(scope, varProperties.value());
+    QV4::Scoped<QV4::VariantObject> oldv(scope, vp->getIndexed(id - firstVarPropertyIndex));
     if (!!oldv)
         oldv->removeVmePropertyReference();
 
@@ -1057,7 +1064,7 @@ void QQmlVMEMetaObject::writeVarProperty(int id, const QV4::Value &value)
     }
 
     // Write the value and emit change signal as appropriate.
-    varProperties.value().asObject()->putIndexed(id - firstVarPropertyIndex, v);
+    vp->putIndexed(id - firstVarPropertyIndex, v);
     activate(object, methodOffset() + id, 0);
 }
 
@@ -1071,7 +1078,8 @@ void QQmlVMEMetaObject::writeProperty(int id, const QVariant &value)
 
         // Importantly, if the current value is a scarce resource, we need to ensure that it
         // gets automatically released by the engine if no other references to it exist.
-        QV4::Scoped<QV4::VariantObject> oldv(scope, varProperties.value().asObject()->getIndexed(id - firstVarPropertyIndex));
+        QV4::ScopedObject vp(scope, varProperties.value());
+        QV4::Scoped<QV4::VariantObject> oldv(scope, vp->getIndexed(id - firstVarPropertyIndex));
         if (!!oldv)
             oldv->removeVmePropertyReference();
 
@@ -1083,7 +1091,7 @@ void QQmlVMEMetaObject::writeProperty(int id, const QVariant &value)
 
         // Write the value and emit change signal as appropriate.
         QVariant currentValue = readPropertyAsVariant(id);
-        varProperties.value().asObject()->putIndexed(id - firstVarPropertyIndex, newv);
+        vp->putIndexed(id - firstVarPropertyIndex, newv);
         if ((currentValue.userType() != value.userType() || currentValue != value))
             activate(object, methodOffset() + id, 0);
     } else {
@@ -1169,7 +1177,7 @@ QV4::ReturnedValue QQmlVMEMetaObject::vmeMethod(int index)
 }
 
 // Used by debugger
-void QQmlVMEMetaObject::setVmeMethod(int index, QV4::PersistentValue function)
+void QQmlVMEMetaObject::setVmeMethod(int index, QV4::ValueRef function)
 {
     if (index < methodOffset()) {
         Q_ASSERT(parentVMEMetaObject());
diff --git a/src/qml/qml/qqmlvmemetaobject_p.h b/src/qml/qml/qqmlvmemetaobject_p.h
index 35592c4906..c9babc0492 100644
--- a/src/qml/qml/qqmlvmemetaobject_p.h
+++ b/src/qml/qml/qqmlvmemetaobject_p.h
@@ -166,7 +166,7 @@ public:
     void registerInterceptor(int index, int valueIndex, QQmlPropertyValueInterceptor *interceptor);
     QV4::ReturnedValue vmeMethod(int index);
     quint16 vmeMethodLineNumber(int index);
-    void setVmeMethod(int index, QV4::PersistentValue function);
+    void setVmeMethod(int index, QV4::ValueRef function);
     QV4::ReturnedValue vmeProperty(int index);
     void setVMEProperty(int index, const QV4::Value &v);
 
diff --git a/src/qml/qml/qqmlxmlhttprequest.cpp b/src/qml/qml/qqmlxmlhttprequest.cpp
index 48072f53c8..10d407a48d 100644
--- a/src/qml/qml/qqmlxmlhttprequest.cpp
+++ b/src/qml/qml/qqmlxmlhttprequest.cpp
@@ -579,13 +579,14 @@ ReturnedValue NodePrototype::method_get_attributes(SimpleCallContext *ctx)
 
 Value NodePrototype::getProto(ExecutionEngine *v4)
 {
+    Scope scope(v4);
     QQmlXMLHttpRequestData *d = xhrdata(v4->v8Engine);
     if (d->nodePrototype.isUndefined()) {
-        Object *p = new (v4->memoryManager) NodePrototype(v4);
-        d->nodePrototype = Value::fromObject(p);
-        v4->v8Engine->freezeObject(d->nodePrototype.value());
+        ScopedObject p(scope, new (v4->memoryManager) NodePrototype(v4));
+        d->nodePrototype = p;
+        v4->v8Engine->freezeObject(p.asValue());
     }
-    return d->nodePrototype.value();
+    return Value::fromReturnedValue(d->nodePrototype.value());
 }
 
 Value Node::create(QV8Engine *engine, NodeImpl *data)
@@ -631,9 +632,9 @@ Value Element::prototype(ExecutionEngine *engine)
         p->setPrototype(NodePrototype::getProto(engine).asObject());
         p->defineAccessorProperty(QStringLiteral("tagName"), NodePrototype::method_get_nodeName, 0);
         d->elementPrototype = p;
-        engine->v8Engine->freezeObject(d->elementPrototype.value());
+        engine->v8Engine->freezeObject(p.asValue());
     }
-    return d->elementPrototype.value();
+    return Value::fromReturnedValue(d->elementPrototype.value());
 }
 
 Value Attr::prototype(ExecutionEngine *engine)
@@ -647,9 +648,9 @@ Value Attr::prototype(ExecutionEngine *engine)
         p->defineAccessorProperty(QStringLiteral("value"), method_value, 0);
         p->defineAccessorProperty(QStringLiteral("ownerElement"), method_ownerElement, 0);
         d->attrPrototype = p;
-        engine->v8Engine->freezeObject(d->attrPrototype.value());
+        engine->v8Engine->freezeObject(p.asValue());
     }
-    return d->attrPrototype.value();
+    return Value::fromReturnedValue(d->attrPrototype.value());
 }
 
 ReturnedValue Attr::method_name(SimpleCallContext *ctx)
@@ -702,9 +703,9 @@ Value CharacterData::prototype(ExecutionEngine *v4)
         p->defineAccessorProperty(QStringLiteral("data"), NodePrototype::method_get_nodeValue, 0);
         p->defineAccessorProperty(QStringLiteral("length"), method_length, 0);
         d->characterDataPrototype = p;
-        v4->v8Engine->freezeObject(d->characterDataPrototype);
+        v4->v8Engine->freezeObject(p.asValue());
     }
-    return d->characterDataPrototype.value();
+    return Value::fromReturnedValue(d->characterDataPrototype.value());
 }
 
 ReturnedValue Text::method_isElementContentWhitespace(SimpleCallContext *ctx)
@@ -735,9 +736,9 @@ Value Text::prototype(ExecutionEngine *v4)
         p->defineAccessorProperty(QStringLiteral("isElementContentWhitespace"), method_isElementContentWhitespace, 0);
         p->defineAccessorProperty(QStringLiteral("wholeText"), method_wholeText, 0);
         d->textPrototype = p;
-        v4->v8Engine->freezeObject(d->textPrototype);
+        v4->v8Engine->freezeObject(p.asValue());
     }
-    return d->textPrototype.value();
+    return Value::fromReturnedValue(d->textPrototype.value());
 }
 
 Value CDATA::prototype(ExecutionEngine *v4)
@@ -749,9 +750,9 @@ Value CDATA::prototype(ExecutionEngine *v4)
         Scoped<Object> p(scope, v4->newObject());
         p->setPrototype(Text::prototype(v4).asObject());
         d->cdataPrototype = p;
-        v4->v8Engine->freezeObject(d->cdataPrototype);
+        v4->v8Engine->freezeObject(p.asValue());
     }
-    return d->cdataPrototype.value();
+    return Value::fromReturnedValue(d->cdataPrototype.value());
 }
 
 Value Document::prototype(ExecutionEngine *v4)
@@ -766,9 +767,9 @@ Value Document::prototype(ExecutionEngine *v4)
         p->defineAccessorProperty(QStringLiteral("xmlStandalone"), method_xmlStandalone, 0);
         p->defineAccessorProperty(QStringLiteral("documentElement"), method_documentElement, 0);
         d->documentPrototype = p;
-        v4->v8Engine->freezeObject(d->documentPrototype);
+        v4->v8Engine->freezeObject(p.asValue());
     }
-    return d->documentPrototype.value();
+    return Value::fromReturnedValue(d->documentPrototype.value());
 }
 
 ReturnedValue Document::load(QV8Engine *engine, const QByteArray &data)
@@ -1284,7 +1285,7 @@ ReturnedValue QQmlXMLHttpRequest::abort(const ValueRef me)
 
 ReturnedValue QQmlXMLHttpRequest::getMe() const
 {
-    return m_me.value().asReturnedValue();
+    return m_me.value();
 }
 
 void QQmlXMLHttpRequest::setMe(const ValueRef me)
diff --git a/src/qml/qml/v8/qv8engine.cpp b/src/qml/qml/v8/qv8engine.cpp
index b62e2150af..e8c84eee35 100644
--- a/src/qml/qml/v8/qv8engine.cpp
+++ b/src/qml/qml/v8/qv8engine.cpp
@@ -120,6 +120,8 @@ QV8Engine::~QV8Engine()
 QVariant QV8Engine::toVariant(const QV4::Value &value, int typeHint)
 {
     Q_ASSERT (!value.isEmpty());
+    QV4::Scope scope(m_v4Engine);
+    QV4::ScopedValue v(scope, value);
 
     if (QV4::VariantObject *v = value.as<QV4::VariantObject>())
         return v->data;
@@ -131,7 +133,7 @@ QVariant QV8Engine::toVariant(const QV4::Value &value, int typeHint)
         return QVariant::fromValue(QV4::JsonObject::toJsonValue(value));
 
     if (typeHint == qMetaTypeId<QJSValue>())
-        return QVariant::fromValue(QJSValue(new QJSValuePrivate(m_v4Engine, value)));
+        return QVariant::fromValue(QJSValue(new QJSValuePrivate(m_v4Engine, v)));
 
     if (QV4::Object *object = value.asObject()) {
         if (typeHint == QMetaType::QJsonObject
@@ -450,9 +452,9 @@ void QV8Engine::initializeGlobal()
                       "    }"\
                       "})"
 
-        QV4::Scoped<QV4::FunctionObject> result(scope, QV4::Script::evaluate(m_v4Engine, QString::fromUtf8(FREEZE_SOURCE), 0));
+        QV4::Scoped<QV4::FunctionObject> result(scope, QV4::Script::evaluate(m_v4Engine, QString::fromUtf8(FREEZE_SOURCE), QV4::ObjectRef::null()));
         Q_ASSERT(!!result);
-        m_freezeObject = result.asValue();
+        m_freezeObject = result;
 #undef FREEZE_SOURCE
     }
 }
@@ -460,10 +462,11 @@ void QV8Engine::initializeGlobal()
 void QV8Engine::freezeObject(const QV4::Value &value)
 {
     QV4::Scope scope(m_v4Engine);
+    QV4::ScopedFunctionObject f(scope, m_freezeObject.value());
     QV4::ScopedCallData callData(scope, 1);
     callData->args[0] = value;
     callData->thisObject = QV4::Value::fromObject(m_v4Engine->globalObject);
-    m_freezeObject.value().asFunctionObject()->call(callData);
+    f->call(callData);
 }
 
 void QV8Engine::gc()
@@ -709,6 +712,8 @@ QV4::ReturnedValue QV8Engine::metaTypeToJS(int type, const void *data)
 // data must point to a place that can store a value of the given type.
 // Returns true if conversion succeeded, false otherwise.
 bool QV8Engine::metaTypeFromJS(const QV4::Value &value, int type, void *data) {
+    QV4::Scope scope(QV8Engine::getV4(this));
+
     // check if it's one of the types we know
     switch (QMetaType::Type(type)) {
     case QMetaType::Bool:
@@ -871,7 +876,7 @@ bool QV8Engine::metaTypeFromJS(const QV4::Value &value, int type, void *data) {
         *reinterpret_cast<void* *>(data) = 0;
         return true;
     } else if (type == qMetaTypeId<QJSValue>()) {
-        *reinterpret_cast<QJSValue*>(data) = QJSValuePrivate::get(new QJSValuePrivate(m_v4Engine, value));
+        *reinterpret_cast<QJSValue*>(data) = QJSValuePrivate::get(new QJSValuePrivate(m_v4Engine, QV4::ScopedValue(scope, value)));
         return true;
     }
 
diff --git a/src/qml/types/qqmldelegatemodel.cpp b/src/qml/types/qqmldelegatemodel.cpp
index 0fa0c73ae0..97aa3ec628 100644
--- a/src/qml/types/qqmldelegatemodel.cpp
+++ b/src/qml/types/qqmldelegatemodel.cpp
@@ -2390,11 +2390,13 @@ QQmlV4Handle QQmlDelegateModelGroup::get(int index)
         model->m_cacheMetaType->initializePrototype();
     QV8Engine *v8 = model->m_cacheMetaType->v8Engine;
     QV4::ExecutionEngine *v4 = QV8Engine::getV4(v8);
-    QV4::Object *o = new (v4->memoryManager) QQmlDelegateModelItemObject(v4, cacheItem);
-    o->setPrototype(model->m_cacheMetaType->modelItemProto.value().asObject());
+    QV4::Scope scope(v4);
+    QV4::ScopedObject o(scope, new (v4->memoryManager) QQmlDelegateModelItemObject(v4, cacheItem));
+    QV4::ScopedObject p(scope, model->m_cacheMetaType->modelItemProto.value());
+    o->setPrototype(p.getPointer());
     ++cacheItem->scriptRef;
 
-    return QQmlV4Handle(QV4::Value::fromObject(o));
+    return QQmlV4Handle(o.asValue());
 }
 
 bool QQmlDelegateModelGroupPrivate::parseIndex(const QV4::Value &value, int *index, Compositor::Group *group) const
@@ -3158,7 +3160,8 @@ public:
     static QV4::ReturnedValue getIndexed(QV4::Managed *m, uint index, bool *hasProperty)
     {
         QV4::ExecutionEngine *v4 = m->engine();
-        QQmlDelegateModelGroupChangeArray *array = m->as<QQmlDelegateModelGroupChangeArray>();
+        QV4::Scope scope(v4);
+        QV4::Scoped<QQmlDelegateModelGroupChangeArray> array(scope, m->as<QQmlDelegateModelGroupChangeArray>());
         if (!array)
             v4->current->throwTypeError();
 
@@ -3170,14 +3173,14 @@ public:
 
         const QQmlChangeSet::Change &change = array->at(index);
 
-        QV4::Object *changeProto = engineData(v4->v8Engine)->changeProto.value().asObject();
-        QQmlDelegateModelGroupChange *object = new (v4->memoryManager) QQmlDelegateModelGroupChange(v4);
-        object->setPrototype(changeProto);
+        QV4::ScopedObject changeProto(scope, engineData(v4->v8Engine)->changeProto.value());
+        QV4::Scoped<QQmlDelegateModelGroupChange> object(scope, new (v4->memoryManager) QQmlDelegateModelGroupChange(v4));
+        object->setPrototype(changeProto.getPointer());
         object->change = change;
 
         if (hasProperty)
             *hasProperty = true;
-        return QV4::Value::fromObject(object).asReturnedValue();
+        return object.asReturnedValue();
     }
 
     static QV4::ReturnedValue get(QV4::Managed *m, const QV4::StringRef name, bool *hasProperty)
diff --git a/src/qml/types/qquickworkerscript.cpp b/src/qml/types/qquickworkerscript.cpp
index ef23a34db8..b955555a82 100644
--- a/src/qml/types/qquickworkerscript.cpp
+++ b/src/qml/types/qquickworkerscript.cpp
@@ -244,9 +244,13 @@ void QQuickWorkerScriptEnginePrivate::WorkerEngine::init()
 // Requires handle and context scope
 QV4::ReturnedValue QQuickWorkerScriptEnginePrivate::WorkerEngine::sendFunction(int id)
 {
-    QV4::FunctionObject *f = createsend.value().asFunctionObject();
-    QV4::ExecutionContext *ctx = f->engine()->current;
-    QV4::Scope scope(ctx->engine);
+    QV4::ExecutionEngine *v4 = createsend.engine();
+    if (!v4)
+        return QV4::Encode::undefined();
+
+    QV4::Scope scope(v4);
+    QV4::ScopedFunctionObject f(scope, createsend.value());
+    QV4::ExecutionContext *ctx = v4->current;
 
     QV4::ScopedValue v(scope);
     try {
@@ -315,12 +319,12 @@ QV4::ReturnedValue QQuickWorkerScriptEnginePrivate::getWorker(WorkerScript *scri
         QV4::Scoped<QV4::Object> api(scope, v4->newObject());
         api->put(QV4::ScopedString(scope, v4->newString("sendMessage")), QV4::ScopedValue(scope, workerEngine->sendFunction(script->id)));
 
-        script->object.value().asObject()->put(QV4::ScopedString(scope, v4->newString("WorkerScript")), api);
+        w->QV4::Object::put(QV4::ScopedString(scope, v4->newString("WorkerScript")), api);
 
         w->setReadOnly(true);
     }
 
-    return script->object.value().asReturnedValue();
+    return script->object.value();
 }
 
 bool QQuickWorkerScriptEnginePrivate::event(QEvent *event)
@@ -351,9 +355,10 @@ void QQuickWorkerScriptEnginePrivate::processMessage(int id, const QByteArray &d
     if (!script)
         return;
 
-    QV4::FunctionObject *f = workerEngine->onmessage.value().asFunctionObject();
-    QV4::ExecutionContext *ctx = f->internalClass->engine->current;
-    QV4::Scope scope(ctx);
+    QV4::ExecutionEngine *v4 = QV8Engine::getV4(workerEngine);
+    QV4::Scope scope(v4);
+    QV4::ScopedFunctionObject f(scope, workerEngine->onmessage.value());
+    QV4::ExecutionContext *ctx = v4->current;
 
     QV4::ScopedValue value(scope, QV4::Serialize::deserialize(data, workerEngine));
 
@@ -396,7 +401,7 @@ void QQuickWorkerScriptEnginePrivate::processLoad(int id, const QUrl &url)
         if (!activation)
             return;
 
-        QV4::Script program(v4, activation.getPointer(), sourceCode, url.toString());
+        QV4::Script program(v4, activation, sourceCode, url.toString());
 
         QV4::ExecutionContext *ctx = v4->current;
         try {
diff --git a/src/qml/util/qqmladaptormodel.cpp b/src/qml/util/qqmladaptormodel.cpp
index 7351e696c6..c4ba42c84a 100644
--- a/src/qml/util/qqmladaptormodel.cpp
+++ b/src/qml/util/qqmladaptormodel.cpp
@@ -228,7 +228,7 @@ public:
             p->setGetter(new (v4->memoryManager) QV4::IndexedBuiltinFunction(v4->rootContext, propertyId, QQmlDMCachedModelData::get_property));
             p->setSetter(new (v4->memoryManager) QV4::IndexedBuiltinFunction(v4->rootContext, propertyId, QQmlDMCachedModelData::set_property));
         }
-        prototype = proto.asValue();
+        prototype = proto;
     }
 
     // QAbstractDynamicMetaObject
@@ -424,12 +424,12 @@ public:
             QQmlAdaptorModelEngineData * const data = engineData(v4->v8Engine);
             type->initializeConstructor(data);
         }
-        QV4::Object *proto = type->prototype.value().asObject();
-        QV4::Object *o = new (proto->engine()->memoryManager) QQmlDelegateModelItemObject(proto->engine(), this);
-        o->setPrototype(proto);
-        QV4::Value data = QV4::Value::fromObject(o);
+        QV4::Scope scope(v4);
+        QV4::ScopedObject proto(scope, type->prototype.value());
+        QV4::ScopedObject o(scope, new (proto->engine()->memoryManager) QQmlDelegateModelItemObject(proto->engine(), this));
+        o->setPrototype(proto.getPointer());
         ++scriptRef;
-        return data.asReturnedValue();
+        return o.asReturnedValue();
     }
 };
 
@@ -599,11 +599,12 @@ public:
     QV4::ReturnedValue get()
     {
         QQmlAdaptorModelEngineData *data = engineData(v4->v8Engine);
-        QV4::Object *o = new (v4->memoryManager) QQmlDelegateModelItemObject(v4, this);
-        o->setPrototype(data->listItemProto.value().asObject());
-        QV4::Value val = QV4::Value::fromObject(o);
+        QV4::Scope scope(v4);
+        QV4::ScopedObject o(scope, new (v4->memoryManager) QQmlDelegateModelItemObject(v4, this));
+        QV4::ScopedObject p(scope, data->listItemProto.value());
+        o->setPrototype(p.getPointer());
         ++scriptRef;
-        return val.asReturnedValue();
+        return o.asReturnedValue();
     }
 
     void setValue(const QString &role, const QVariant &value)
diff --git a/src/quick/items/context2d/qquickcanvasitem.cpp b/src/quick/items/context2d/qquickcanvasitem.cpp
index f21abdab67..78369eb404 100644
--- a/src/quick/items/context2d/qquickcanvasitem.cpp
+++ b/src/quick/items/context2d/qquickcanvasitem.cpp
@@ -666,7 +666,7 @@ void QQuickCanvasItem::updatePolish()
         callData->thisObject = QV4::Value::fromReturnedValue(QV4::QObjectWrapper::wrap(v4, this));
 
         foreach (int key, animationCallbacks.keys()) {
-            QV4::FunctionObject *f = animationCallbacks.value(key).value().asFunctionObject();
+            QV4::ScopedFunctionObject f(scope, animationCallbacks.value(key).value());
             callData->args[0] = QV4::Value::fromUInt32(QDateTime::currentDateTimeUtc().toTime_t());
             f->call(callData);
         }
@@ -789,7 +789,9 @@ void QQuickCanvasItem::requestAnimationFrame(QQmlV4Function *args)
 
     static int id = 0;
 
-    d->animationCallbacks.insert(++id, QV4::PersistentValue((*args)[0]));
+    QV4::Scope scope(QV8Engine::getV4(args->engine()));
+    QV4::ScopedValue v(scope, (*args)[0]);
+    d->animationCallbacks.insert(++id, QV4::PersistentValue(v));
 
     if (isVisible())
         polish();
diff --git a/src/quick/items/context2d/qquickcontext2d.cpp b/src/quick/items/context2d/qquickcontext2d.cpp
index 1930fb69c9..ea3bd77509 100644
--- a/src/quick/items/context2d/qquickcontext2d.cpp
+++ b/src/quick/items/context2d/qquickcontext2d.cpp
@@ -915,8 +915,10 @@ static QV4::Value qt_create_image_data(qreal w, qreal h, QV8Engine* engine, cons
 {
     QQuickContext2DEngineData *ed = engineData(engine);
     QV4::ExecutionEngine *v4 = QV8Engine::getV4(engine);
-    QQuickJSContext2DPixelData *pixelData = new (v4->memoryManager) QQuickJSContext2DPixelData(v4);
-    pixelData->setPrototype(ed->pixelArrayProto.value().asObject());
+    QV4::Scope scope(v4);
+    QV4::Scoped<QQuickJSContext2DPixelData> pixelData(scope, new (v4->memoryManager) QQuickJSContext2DPixelData(v4));
+    QV4::ScopedObject p(scope, ed->pixelArrayProto.value());
+    pixelData->setPrototype(p.getPointer());
 
     if (image.isNull()) {
         pixelData->image = QImage(w, h, QImage::Format_ARGB32);
@@ -927,7 +929,7 @@ static QV4::Value qt_create_image_data(qreal w, qreal h, QV8Engine* engine, cons
     }
 
     QQuickJSContext2DImageData *imageData = new (v4->memoryManager) QQuickJSContext2DImageData(v4);
-    imageData->pixelData = QV4::Value::fromObject(pixelData);
+    imageData->pixelData = pixelData.asValue();
     return QV4::Value::fromObject(imageData);
 }
 
@@ -1362,7 +1364,7 @@ QV4::ReturnedValue QQuickJSContext2D::method_get_fillStyle(QV4::SimpleCallContex
         QString str = QString::fromLatin1("rgba(%1, %2, %3, %4)").arg(color.red()).arg(color.green()).arg(color.blue()).arg(alphaString);
         return QV4::Value::fromString(ctx->engine->newString(str)).asReturnedValue();
     }
-    return r->context->m_fillStyle.value().asReturnedValue();
+    return r->context->m_fillStyle.value();
 }
 
 QV4::ReturnedValue QQuickJSContext2D::method_set_fillStyle(QV4::SimpleCallContext *ctx)
@@ -1477,7 +1479,7 @@ QV4::ReturnedValue QQuickJSContext2D::method_get_strokeStyle(QV4::SimpleCallCont
         QString str = QString::fromLatin1("rgba(%1, %2, %3, %4)").arg(color.red()).arg(color.green()).arg(color.blue()).arg(alphaString);
         return QV4::Value::fromString(ctx->engine->newString(str)).asReturnedValue();
     }
-    return r->context->m_strokeStyle.value().asReturnedValue();
+    return r->context->m_strokeStyle.value();
 }
 
 QV4::ReturnedValue QQuickJSContext2D::method_set_strokeStyle(QV4::SimpleCallContext *ctx)
@@ -1559,10 +1561,11 @@ QV4::ReturnedValue QQuickJSContext2DPrototype::method_createLinearGradient(QV4::
         }
         QQuickContext2DEngineData *ed = engineData(engine);
 
-        QQuickContext2DStyle *gradient = new (v4->memoryManager) QQuickContext2DStyle(v4);
-        gradient->setPrototype(ed->gradientProto.value().asObject());
+        QV4::Scoped<QQuickContext2DStyle> gradient(scope, new (v4->memoryManager) QQuickContext2DStyle(v4));
+        QV4::ScopedObject p(scope, ed->gradientProto.value());
+        gradient->setPrototype(p.getPointer());
         gradient->brush = QLinearGradient(x0, y0, x1, y1);
-        return QV4::Value::fromObject(gradient).asReturnedValue();
+        return gradient.asReturnedValue();
     }
 
     return ctx->thisObject.asReturnedValue();
@@ -1613,10 +1616,11 @@ QV4::ReturnedValue QQuickJSContext2DPrototype::method_createRadialGradient(QV4::
 
         QQuickContext2DEngineData *ed = engineData(engine);
 
-        QQuickContext2DStyle *gradient = new (v4->memoryManager) QQuickContext2DStyle(v4);
-        gradient->setPrototype(ed->gradientProto.value().asObject());
+        QV4::Scoped<QQuickContext2DStyle> gradient(scope, new (v4->memoryManager) QQuickContext2DStyle(v4));
+        QV4::ScopedObject p(scope, ed->gradientProto.value());
+        gradient->setPrototype(p.getPointer());
         gradient->brush = QRadialGradient(QPointF(x1, y1), r0+r1, QPointF(x0, y0));
-        return QV4::Value::fromObject(gradient).asReturnedValue();
+        return gradient.asReturnedValue();
     }
 
     return ctx->thisObject.asReturnedValue();
@@ -1659,10 +1663,11 @@ QV4::ReturnedValue QQuickJSContext2DPrototype::method_createConicalGradient(QV4:
 
         QQuickContext2DEngineData *ed = engineData(engine);
 
-        QQuickContext2DStyle *gradient = new (v4->memoryManager) QQuickContext2DStyle(v4);
-        gradient->setPrototype(ed->gradientProto.value().asObject());
+        QV4::Scoped<QQuickContext2DStyle> gradient(scope, new (v4->memoryManager) QQuickContext2DStyle(v4));
+        QV4::ScopedObject p(scope, ed->gradientProto.value());
+        gradient->setPrototype(p.getPointer());
         gradient->brush = QConicalGradient(x, y, angle);
-        return QV4::Value::fromObject(gradient).asReturnedValue();
+        return gradient.asReturnedValue();
     }
 
     return ctx->thisObject.asReturnedValue();
@@ -2080,7 +2085,7 @@ QV4::ReturnedValue QQuickJSContext2D::method_get_path(QV4::SimpleCallContext *ct
     QQuickJSContext2D *r = ctx->thisObject.as<QQuickJSContext2D>();
     CHECK_CONTEXT(r)
 
-    return r->context->m_v4path.value().asReturnedValue();
+    return r->context->m_v4path.value();
 }
 
 QV4::ReturnedValue QQuickJSContext2D::method_set_path(QV4::SimpleCallContext *ctx)
@@ -4041,7 +4046,7 @@ QQuickContext2D::~QQuickContext2D()
 
 QV4::Value QQuickContext2D::v4value() const
 {
-    return m_v4value.value();
+    return QV4::Value::fromReturnedValue(m_v4value.value());
 }
 
 QStringList QQuickContext2D::contextNames() const
@@ -4278,10 +4283,12 @@ void QQuickContext2D::setV8Engine(QV8Engine *engine)
 
         QQuickContext2DEngineData *ed = engineData(engine);
         QV4::ExecutionEngine *v4Engine = QV8Engine::getV4(engine);
-        QQuickJSContext2D *wrapper = new (v4Engine->memoryManager) QQuickJSContext2D(v4Engine);
-        wrapper->setPrototype(ed->contextPrototype.value().asObject());
+        QV4::Scope scope(v4Engine);
+        QV4::Scoped<QQuickJSContext2D> wrapper(scope, new (v4Engine->memoryManager) QQuickJSContext2D(v4Engine));
+        QV4::ScopedObject p(scope, ed->contextPrototype.value());
+        wrapper->setPrototype(p.getPointer());
         wrapper->context = this;
-        m_v4value = QV4::Value::fromObject(wrapper);
+        m_v4value = wrapper;
     }
 }
 
diff --git a/src/quick/items/qquickloader.cpp b/src/quick/items/qquickloader.cpp
index 3dee563de2..63490ef2cc 100644
--- a/src/quick/items/qquickloader.cpp
+++ b/src/quick/items/qquickloader.cpp
@@ -577,8 +577,8 @@ void QQuickLoader::setSource(QQmlV4Function *args)
     QUrl sourceUrl = d->resolveSourceUrl(args);
     if (!ipv.isUndefined()) {
         d->disposeInitialPropertyValues();
-        d->initialPropertyValues = ipv;
-        d->qmlGlobalForIpv = args->qmlGlobal();
+        d->initialPropertyValues = ipv.asReturnedValue();
+        d->qmlGlobalForIpv = args->qmlGlobal().asReturnedValue();
     }
 
     setSource(sourceUrl, false); // already cleared and set ipv above.
@@ -644,7 +644,11 @@ void QQuickLoaderPrivate::setInitialState(QObject *obj)
 
     QQmlComponentPrivate *d = QQmlComponentPrivate::get(component);
     Q_ASSERT(d && d->engine);
-    d->initializeObjectWithInitialProperties(qmlGlobalForIpv.value(), initialPropertyValues.value(), obj);
+    QV4::ExecutionEngine *v4 = qmlGlobalForIpv.engine();
+    Q_ASSERT(v4);
+    QV4::Scope scope(v4);
+    QV4::ScopedValue ipv(scope, initialPropertyValues.value());
+    d->initializeObjectWithInitialProperties(qmlGlobalForIpv, ipv, obj);
 }
 
 void QQuickLoaderIncubator::statusChanged(Status status)
diff --git a/tests/auto/qml/qqmlecmascript/testtypes.h b/tests/auto/qml/qqmlecmascript/testtypes.h
index a77c300d49..cba0267b26 100644
--- a/tests/auto/qml/qqmlecmascript/testtypes.h
+++ b/tests/auto/qml/qqmlecmascript/testtypes.h
@@ -1233,13 +1233,13 @@ public:
     {
         QQmlData *ddata = QQmlData::get(this);
         assert(ddata);
-        QV4::QObjectWrapper *thisObject = ddata->jsWrapper.value().as<QV4::QObjectWrapper>();
+        QV4::QObjectWrapper *thisObject = QV4::Value::fromReturnedValue(ddata->jsWrapper.value()).as<QV4::QObjectWrapper>();
         assert(thisObject);
 
         QQmlData *otherDData = QQmlData::get(other);
         assert(otherDData);
 
-        thisObject->defineDefaultProperty(QStringLiteral("autoTestStrongRef"), otherDData->jsWrapper.value());
+        thisObject->defineDefaultProperty(QStringLiteral("autoTestStrongRef"), QV4::Value::fromReturnedValue(otherDData->jsWrapper.value()));
     }
 
     void setEngine(QQmlEngine* declarativeEngine)
diff --git a/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp b/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
index d85b974175..a5f30a01c2 100644
--- a/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
+++ b/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
@@ -3905,8 +3905,11 @@ void tst_qqmlecmascript::verifyContextLifetime(QQmlContextData *ctxt) {
 
             if (qmlglobal.isUndefined())
                 continue;
+            QV4::Scope scope(QV8Engine::getV4((engine)));
+            QV4::ScopedValue qml(scope, qmlglobal.value());
 
-            scriptContext = QV4::QmlContextWrapper::getContext(qmlglobal);
+            scriptContext = QV4::QmlContextWrapper::getContext(qml);
+            qml = QV4::Encode::undefined();
 
             {
                 QV4::Scope scope(QV8Engine::getV4((engine)));
@@ -3915,7 +3918,8 @@ void tst_qqmlecmascript::verifyContextLifetime(QQmlContextData *ctxt) {
             }
 
             engine->gc();
-            newContext = QV4::QmlContextWrapper::getContext(qmlglobal);
+            qml = qmlglobal.value();
+            newContext = QV4::QmlContextWrapper::getContext(qml);
             QVERIFY(scriptContext == newContext);
         }
     }
@@ -4992,11 +4996,11 @@ void tst_qqmlecmascript::propertyVarInheritance()
     {
         // XXX NOTE: this is very implementation dependent.  QDVMEMO->vmeProperty() is the only
         // public function which can return us a handle to something in the varProperties array.
-        QV4::Value tmp = QV4::Value::fromReturnedValue(icovmemo->vmeProperty(ico5->metaObject()->indexOfProperty("circ")));
+        QV4::ReturnedValue tmp = icovmemo->vmeProperty(ico5->metaObject()->indexOfProperty("circ"));
         icoCanaryHandle = tmp;
-        tmp = QV4::Value::fromReturnedValue(ccovmemo->vmeProperty(cco5->metaObject()->indexOfProperty("circ")));
+        tmp = ccovmemo->vmeProperty(cco5->metaObject()->indexOfProperty("circ"));
         ccoCanaryHandle = tmp;
-        tmp = QV4::Value::nullValue();
+        tmp = QV4::Encode::null();
         QVERIFY(!icoCanaryHandle.isUndefined());
         QVERIFY(!ccoCanaryHandle.isUndefined());
         gc(engine);
@@ -5038,9 +5042,7 @@ void tst_qqmlecmascript::propertyVarInheritance2()
     QCOMPARE(childObject->property("textCanary").toInt(), 10);
     QV4::WeakValue childObjectVarArrayValueHandle;
     {
-        QV4::Value tmp = QV4::Value::fromReturnedValue(QQmlVMEMetaObject::get(childObject)->vmeProperty(childObject->metaObject()->indexOfProperty("vp")));
-        childObjectVarArrayValueHandle = tmp;
-        tmp = QV4::Value::nullValue();
+        childObjectVarArrayValueHandle = QQmlVMEMetaObject::get(childObject)->vmeProperty(childObject->metaObject()->indexOfProperty("vp"));
         QVERIFY(!childObjectVarArrayValueHandle.isUndefined());
         gc(engine);
         QVERIFY(!childObjectVarArrayValueHandle.isUndefined()); // should not have been collected yet.