{"ast_node_type":"variable","tokens":[{"end":72,"kind":"keyword","start":0,"text":"let"}]}
        let (Some(unsize_did), Some(coerce_unsized_did)) = traits else {
            (self.tcx.lang_items().unsize_trait(), self.tcx.lang_items().coerce_unsized_trait());
            debug!("missing Unsize or CoerceUnsized traits");