Clippy lint · Correctness · checked with Clippy 0.1.99

clippy::never_loop: this loop never actually loops

What it meansChecks for loops that will always break, return or continue an outer loop. It is in the correctness group and denied by default (the build fails).

What you see

error: this loop never actually loops
 --> main.rs:3:1
  |
3 | / loop {
4 | |     ..;
5 | |     break;
6 | | }
  | |_^
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#never_loop
  = note: `#[deny(clippy::never_loop)]` 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 loop never loops, all it does is obfuscating the code.

Code that is almost certainly wrong. Denied by default: the build fails until you fix it or allow it.

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

loop {
    ..;
    break;
}

Turn it off, or on

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

On one item

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

Whole crate (Cargo.toml)

[lints.clippy]
never_loop = "allow"

One run

cargo clippy -- -A clippy::never-loop

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.

Correctnessgroup

denydefault level

yesfixed by cargo clippy --fix

pre 1.29.0added in Rust

Clippy's own documentation

What it does

Checks for loops that will always break, return or continue an outer loop.

Why is this bad?

This loop never loops, all it does is obfuscating the code.

Example

loop {
    ..;
    break;
}

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

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