Clippy lint · Complexity · checked with Clippy 0.1.99

clippy::explicit_auto_deref: deref which would be done by auto-deref

What it meansChecks for dereferencing expressions which would be covered by auto-deref. It is in the complexity group and warns by default.

What you see

warning: deref which would be done by auto-deref
 --> main.rs:4:15
  |
4 | let y: &str = &*x;
  |               ^^^ help: try: `&x`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#explicit_auto_deref
  = note: `#[warn(clippy::explicit_auto_deref)]` on by default

Real output of Clippy 0.1.99 (Rust 1.99) on the example below. Names and line numbers in yours will differ.

Does it matter?

This unnecessarily complicates the code.

Code that does something simple in a complicated way. Warns by default.

How to fix it

Clippy can fix this one for you: run cargo clippy --fix (add --allow-dirty if you have uncommitted changes). Review the diff before you commit.

Flagged

let x = String::new();
let y: &str = &*x;

Write this instead

let x = String::new();
let y: &str = &x;

Turn it off, or on

Allow it where it does not fit your code, as narrowly as you can:

On one item

#[allow(clippy::explicit_auto_deref)]
fn my_function() { /* ... */ }

Whole crate (Cargo.toml)

[lints.clippy]
explicit_auto_deref = "allow"

One run

cargo clippy -- -A clippy::explicit-auto-deref

The [lints] table needs Rust 1.74 or newer. In a workspace, put it under [workspace.lints.clippy] and add [lints] workspace = true to each member.

Complexitygroup

warndefault level

yesfixed by cargo clippy --fix

1.64.0added in Rust

Clippy's own documentation

What it does

Checks for dereferencing expressions which would be covered by auto-deref.

Why is this bad?

This unnecessarily complicates the code.

Example

let x = String::new();
let y: &str = &*x;

Use instead:

let x = String::new();
let y: &str = &x;

From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.

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