{"ast_node_type":"variable","tokens":[{"end":65,"kind":"keyword","start":0,"text":"let"}]}
                let args: Cow<'_, [FnArg<'tcx, M::Provenance>]> =
                // Special handling for the closure ABI: untuple the last argument.
                    if caller_abi == ExternAbi::RustCall && !args.is_empty() {