Clippy lint · Correctness · checked with Clippy 0.1.99

clippy::redundant_comparisons: Checks for ineffective double comparisons against constants

What it meansChecks for ineffective double comparisons against constants. It is in the correctness group and denied by default (the build fails).

Does it matter?

Only one of the comparisons has any effect on the result, the programmer probably intended to flip one of the comparison operators, or compare a different value entirely.

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

How to fix it

Clippy does not fix this one automatically. Change the code by hand:

Flagged

if status_code <= 400 && status_code < 500 {}

Turn it off, or on

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

On one item

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

Whole crate (Cargo.toml)

[lints.clippy]
redundant_comparisons = "allow"

One run

cargo clippy -- -A clippy::redundant-comparisons

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

nofixed by cargo clippy --fix

1.73.0added in Rust

Clippy's own documentation

What it does

Checks for ineffective double comparisons against constants.

Why is this bad?

Only one of the comparisons has any effect on the result, the programmer probably intended to flip one of the comparison operators, or compare a different value entirely.

Example

if status_code <= 400 && status_code < 500 {}

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

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