Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::manual_range_contains: manual `Range::contains` implementation
What it meansChecks for expressions like x >= 3 && x < 8 that could be more readably expressed as (3..8).contains(&x). It is in the style group and warns by default.
What you see
warning: manual `Range::contains` implementation --> main.rs:6:9 | 6 | assert!(x >= 3 && x < 8); | ^^^^^^^^^^^^^^^ help: use: `(3..8).contains(&x)` | = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#manual_range_contains = note: `#[warn(clippy::manual_range_contains)]` 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?
contains expresses the intent better and has less failure modes (such as fencepost errors or using || instead of &&).
Code that works but is not idiomatic Rust. 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
// given
let x = 6;
assert!(x >= 3 && x < 8);
Write this instead
assert!((3..8).contains(&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::manual_range_contains)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
manual_range_contains = "allow"One run
cargo clippy -- -A clippy::manual-range-containsThe [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.
Settings in clippy.toml
msrv: The minimum rust version that the project supports. Defaults to the rust-version field in Cargo.toml
Clippy's own documentation
What it does
Checks for expressions like x >= 3 && x < 8 that could
be more readably expressed as (3..8).contains(&x).
Why is this bad?
contains expresses the intent better and has less
failure modes (such as fencepost errors or using || instead of &&).
Example
// given
let x = 6;
assert!(x >= 3 && x < 8);
Use instead:
assert!((3..8).contains(&x));
Limitations
Out-of-range checks on floating-point types, such as q < 0.0 || q > 1.0,
are not linted. For NaN, that expression is false, but
!(0.0..=1.0).contains(&q) is true, so the suggested rewrite would
change control flow.
Configuration
-
msrv: The minimum rust version that the project supports. Defaults to therust-versionfield inCargo.toml(default:
current version)
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
- needless_returnunneeded `return` statement
- new_without_defaultChecks for public types with a pub fn new() -> Self method and no implementation of Default
- len_zeroChecks for getting the length of something via .len() just to compare to zero, and suggests using .is_empty() where applicable
- manual_non_exhaustiveChecks for manual implementations of the non-exhaustive pattern
- manual_ok_orthis pattern reimplements `Option::ok_or`
- manual_pattern_char_comparisonthis manual char comparison can be written more succinctly
- manual_repeat_nthis `repeat().take()` can be written more concisely
- manual_rotatethere is no need to manually implement bit rotation
- manual_saturating_arithmeticChecks for .checked_add/sub(x).unwrap_or(MAX/MIN)
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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