{"ast_node_type":"variable","tokens":[{"end":76,"kind":"keyword","start":0,"text":"let"}]}
        let trait_def_id = predicate.projection_term.trait_def_id(self.tcx);
        // Check that this is a projection from the `Future` trait.
        if !self.tcx.is_lang_item(trait_def_id, LangItem::Future) {