Crash when calling hasOwnProperty() on a JS Proxy Object

#include <QtCore/qcoreapplication.h>
#include <QtCore/qdebug.h>
#include <QtCore/qobject.h>
#include <QtCore/qtimer.h>
#include <QtCore/qstring.h>
#include <QtQml/qjsengine.h>
#include <QtQml/qjsvalue.h>

static const QString jsCode = QStringLiteral(R"666(
     (function(handler){
        const target = {};
        const proxy = new Proxy(target, handler);
        if (proxy.hasOwnProperty("does_not_exist")) { // crashes
            console.log("FAIL");
        } else {
            console.log("SUCCESS");
        }
     })
)666");

class ProxyHandler: public QObject {
    Q_OBJECT
public:
    // This is a non-sense handler, but should be valid.
    Q_INVOKABLE QJSValue getOwnPropertyDescriptor(QJSValue target, const QJSValue &key)
    {
        Q_ASSERT(key.isString());

        QJSValue result;
        QString name = key.toString();
        if (target.hasOwnProperty(name)) {
            QJSValue value = target.property(name);
            result = qjsEngine(this)->newObject();
            result.setProperty(QStringLiteral("configurable"), true);
            result.setProperty(QStringLiteral("enumerable"), true);
            result.setProperty(QStringLiteral("writable"), false);
            result.setProperty(QStringLiteral("value"), value);
        }
        return result;
    }
};

void test() {
    QJSEngine engine;
    engine.installExtensions(QJSEngine::ConsoleExtension);
    QJSValue proxyTest = engine.evaluate(jsCode, QStringLiteral("proxy.js"));
    if (proxyTest.isError())
        qWarning() << "Error: " << proxyTest.toString();
    Q_ASSERT(!proxyTest.isError());

    QJSValue handler = engine.newQObject(new ProxyHandler());
    QJSValue result = proxyTest.call(QJSValueList{ handler });
    if (result.isError())
        qWarning() << "Error: " << result.toString();
    Q_ASSERT(!result.isError());

    QCoreApplication::exit(0);
}

int main(int argc, char *argv[])
{
    QCoreApplication app(argc, argv);
    QTimer::singleShot(0, &test);
    return app.exec();
}

#include "main.moc"