Crash in QQmlBoundSignal constructor

We end up creating a QQmlBoundSignal instance on something that is not a signal. This results in a crash.

import QtQuick 2.0

Rectangle {
    width: 100
    height: 62

    function foo() {
        console.log("foo")
    }

    onFoo: console.log("onFoo")
}

In the code above, it looks like the onFoo line is triggering a "store signal" instruction even though there's no foo signal declared. There is a foo function declared, though, which seems to be responsible for the crash.