{"ast_node_type":"variable","tokens":[{"end":95,"kind":"keyword","start":0,"text":"let"}]}
                    let type_ref = self.lower_type_ref_opt(type_arg.ty(), impl_trait_lower_fn);
                ast::GenericArg::TypeArg(type_arg) => {
                    args.push(GenericArg::Type(type_ref));