{"ast_node_type":"variable","tokens":[{"end":61,"kind":"keyword","start":0,"text":"let"}]}
        let type_param_mode = ParamLoweringMode::Placeholder;
        let impl_trait_mode = ImplTraitLoweringState::new(ImplTraitLoweringMode::Disallowed);
        let in_binders = DebruijnIndex::INNERMOST;