{"ast_node_type":"variable","tokens":[{"end":91,"kind":"keyword","start":0,"text":"let"}]}
            let rigid_ctor = ty::AliasTerm::new_from_args(cx, alias.def_id, identity_args);
            let identity_args = self.fresh_args_for_item(alias.def_id);
            let ctor_term = rigid_ctor.to_term(cx);