RS.CLIPPY.MAP_IDENTITY

Using iterator.map(|x| x)

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

What it does

Checks for instances of map(f) where f is the identity function.

Why is this bad?

It can be written more concisely without the call to map.

Example

let x = [1, 2, 3];
let y: Vec<_> = x.iter().map(|x| x).map(|x| 2*x).collect();

Use instead:

let x = [1, 2, 3];
let y: Vec<_> = x.iter().map(|x| 2*x).collect();