Can't reference #[template_child] elements to clone within signals

[rharish101]

Consider the following code:

#[template_child]
foo {
    ...
}
#[template_child]
bar {
    ...
    connect_changed[sender, foo] => move |this| {
        ...
    }
}

This used to work in 0.5.0, but fails with 0.6.x and the latest main branch.