{"ast_node_type":"variable","tokens":[{"end":87,"kind":"keyword","start":0,"text":"let"}]}
    let (used_items, mentioned_items) = collect_items_of_instance(tcx, instance, mode);
) -> (&'tcx [Spanned<MonoItem<'tcx>>], &'tcx [Spanned<MonoItem<'tcx>>]) {