qmllint doesn't see signal handlers

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);
^^^^^^^^^^^^^^^^