Clippy lint · Pedantic · checked with Clippy 0.1.99

clippy::ref_binding_to_reference: Checks for ref bindings which create a reference to a reference

What it meansChecks for ref bindings which create a reference to a reference. It is in the pedantic group and off by default.

Does it matter?

The address-of operator at the use site is clearer about the need for a reference.

Stricter lints with some false positives. Off by default; opt in with clippy::pedantic.

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 = Some("");
if let Some(ref x) = x {
    // use `x` here
}

Write this instead

let x = Some("");
if let Some(x) = x {
    // use `&x` here
}

Turn it off, or on

It is off by default. To use it, set it to warn or deny:

Whole crate (Cargo.toml)

[lints.clippy]
ref_binding_to_reference = "warn"

In code

#![warn(clippy::ref_binding_to_reference)]

One run

cargo clippy -- -W clippy::ref-binding-to-reference

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.

Pedanticgroup

allowdefault level

yesfixed by cargo clippy --fix

1.54.0added in Rust

Clippy's own documentation

What it does

Checks for ref bindings which create a reference to a reference.

Why is this bad?

The address-of operator at the use site is clearer about the need for a reference.

Example

let x = Some("");
if let Some(ref x) = x {
    // use `x` here
}

Use instead:

let x = Some("");
if let Some(x) = x {
    // use `&x` here
}

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

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