The generated code from qmltocpp is different from what's written in QML

*I have attached the project and the generated C++ code by qmltocpp, respectively, "Buttons.zip" and "Buttons.dir.zip."

What the sample application does is to present three CheckBoxes and a Button.

When the user clicks on the Button, the application outputs the number of checked CheckBoxes, like so:

import QtQuick
import QtQuick.Controls
Rectangle {
    width: 480; height: 272
    Column {
        CheckBox {
            id: checkbox1
            text: checked ? "checked" : "unchecked"
        }
        CheckBox {
            id: checkbox2
            text: checked ? "checked" : "unchecked"
        }
        CheckBox {
            id: checkbox3
            text: checked ? "checked" : "unchecked"
        }
        Button{
            text: "Calculate"
            property int numChecked: 0
            onClicked: {
                numChecked = checkbox1.checked ? 1 : 0
                           + checkbox2.checked ? 1 : 0
                           + checkbox3.checked ? 1 : 0;
                console.log("The number of checked checkboxes = " + numChecked);
            }
        }
    }
}

The issue is, even when more than 1 CheckBoxes are checked, the application always outputs The number of checked checkboxes = 1.

When none of the CheckBox is checked, it properly outputs The number of checked checkboxes = 0.

I checked the concerning part of the generated code(
void Buttons::button_onClicked_bindingFunctor::operator()() const in Buttons.cpp), and found out that the operations were wrong, as in it always adds 1 to 0, therefore, the application cannot output the value more than 1, even when more than 1 CheckBoxes are checked.