RS.CLIPPY.MUT_MUT

Usage of double-mut refs, e.g., `&mut &mut ...`

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

What it does

Checks for instances of mut mut references.

Why is this bad?

Multiple muts don't add anything meaningful to the source. This is either a copy'n'paste error, or it shows a fundamental misunderstanding of references.

Example

let x = &mut &mut y;