instanceof don't work with inline components

import QtQuick

Item {
   component Foo : Item {
        property int a: 17
   }
   Foo {
        id: foo
        a: 15
   }
   Boo {
        id: boo
        b: 3
   }
   Component.onCompleted: {
        console.log("is foo Item: ", foo instanceof Item);
        console.log("is foo Foo: ", foo instanceof Foo);
        console.log("is boo Boo: ", boo instanceof Boo);
   }
}

import QtQuick

Item {
   property int b: 17
}