Crash when evaluating an invalid QQmlExpression.

#include <QtQml/QQmlExpression>
#include <QtQml/QQmlEngine>
#include <QtCore/QCoreApplication>
int main(int nargs, char **args)
{
 QCoreApplication app(nargs,args);
 // I know the following line is terrible, but it was just for keeping this short.
 QQmlExpression((new QQmlEngine())->rootContext(),new QObject(),"abc=123").evaluate(new bool());
}