Critical: Error: Unknown method return type: QList<QJSValue>

Question

On Qt Installer gui Scripting API I see

object[] findChildren(object parent, string objectName)

Returns all descendants of parent that have objectName as name.

Then I wrote

function Controller()
{
}

Controller.prototype.IntroductionPageCallback = function()
{

    var widget = gui.currentPageWidget(); // get the current wizard page
    if (widget != null) {
        widget.title = "New title."; // set the page title
        widget.MessageLabel.setText("New Message."); // set the welcome text
        var list = gui.findChildren(widget, "*")
    }
}

This almost work, I mean it changes widget title and MessageLabel.

But executing the installer (installer.exe --verbose) reports an error

Critical: Error: Unknown method return type: QList<QJSValue>

How can I handle this?

It looks like similar error was reported before at https://forum.qt.io/topic/95669/ifw-critical-error-unknown-method-return-type-qlist-qjsvalue-when-trying-to-call-findchildren