{"ast_node_type":"variable","tokens":[{"end":77,"kind":"keyword","start":0,"text":"let"}]}
                    let guar = *emitted_bad_param_err.get_or_insert_with(|| {
                ty::GenericParamDefKind::Const { .. } => {
                        self.dcx().emit_err(crate::errors::ReturnTypeNotationIllegalParam::Const {