qmllint does not warn about writing global variables

In QML, it is not allowed to write to global variables. In the attached example, the engine will error out with 'Error: Invalid write to global property "unexistingVar"', but qmllint does not emit any warning.untitled24.zip

    function test1() {
        // qmlls via qmllint should warn about writing to global variables (the let/const/var is missing here!)
        unexistingVar = 424242;
    }