{"ast_node_type":"variable","tokens":[{"end":63,"kind":"keyword","start":0,"text":"let"}]}
                        let (ty, span) = match fn_decl.output {
                    return self.get_fn_decl(hir_id).map(|(_, fn_decl)| {
                            hir::FnRetTy::DefaultReturn(span) => ("()".to_string(), span),