RS.CLIPPY.ITER_KV_MAP

Iterating on map using `iter` when `keys` or `values` would do

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_kv_map. Copyright ©2025 The Rust Team. All rights reserved.

What it does

Checks for iterating a map (HashMap or BTreeMap) and ignoring either the keys or values.

Why is this bad?

Readability. There are keys and values methods that can be used to express that we only need the keys or the values.

Example

let map: HashMap<u32, u32> = HashMap::new();
let values = map.iter().map(|(_, value)| value).collect::<Vec<_>>();

Use instead:

let map: HashMap<u32, u32> = HashMap::new();
let values = map.values().collect::<Vec<_>>();

Configuration

msrv: The minimum rust version that the project supports. Defaults to the rust-version field in Cargo.toml

(default: current version)