{"ast_node_type":"variable","tokens":[{"end":79,"kind":"keyword","start":0,"text":"let"}]}
            let sp = arg_exprs.last().map_or(call_expr.span, |expr| expr.span);
        if fn_sig.abi == rustc_abi::ExternAbi::RustCall {
            if let Some(ty) = fn_sig.inputs().last().copied() {