RS.CLIPPY.ITER_ON_SINGLE_ITEMS

Iterator for array of length 1

This checker is a Clippy lint created by The Rust Project Contributors. The documentation shown here is a copy of the original documentation for: iter_on_single_items. Copyright ©2025 The Rust Team. All rights reserved.

What it does

Checks for calls to iter, iter_mut or into_iter on collections containing a single item

Why is this bad?

It is simpler to use the once function from the standard library:

Example

let a = [123].iter();
let b = Some(123).into_iter();

Use instead:

use std::iter;
let a = iter::once(&123);
let b = iter::once(123);

Known problems

The type of the resulting iterator might become incompatible with its usage