Trying to connect to signal handlers through javascript code generates confusing warnings that the signal handler doesn't exist, even when explicitly specifying the type using 'as':

function foo() {}

Loader {
id: loader
   sourceComponent: Item
    onLoaded:

}

This generates the following qmllint warnings:

Warning: main.qml:33:25: Member "onVisibleChanged" not found on type "QQuickItem" [missing-property]
(loader.item as Item).onVisibleChanged.connect(foo);
^^^^^^^^^^^^^^^^
Warning: main.qml:33:25: Could not compile binding for onLoaded: Cannot load property onVisibleChanged from QQuickItem of QQuickItem. [compiler]
(loader.item as Item).onVisibleChanged.connect(foo);
^^^^^^^^^^^^^^^^