remove superfluous mut
@@ -242,7 +242,7 @@ pub(crate) fn register(f: &mut HashMap<String, Builtin>) {
);
f.insert(
"zip".to_owned(),
- Box::new(|mut args, _| {
+ Box::new(|args, _| {
let lists = args
.get_variadic()?
.into_iter()
