It is not possible to handle signals named top, bottom, left and right

Item {
    signal top
    signal bottom
    signal left
    signal right
}

On attempt to handle the signal e.g.

onRight: console.log("on right!")

The error is logged:

Cannot assign to non-existent property "onRight"

Seems to be a naming collision with the anchor positioning.

The same code works perfectly fine ok Qt 5.