Clippy lint · Suspicious · checked with Clippy 0.1.99

clippy::almost_complete_range: almost complete ascii range

What it meansChecks for ranges which almost include the entire range of letters from ‘a’ to ‘z’ or digits from ‘0’ to ‘9’, but don’t because they’re a half open range. It is in the suspicious group and warns by default.

What you see

warning: almost complete ascii range
 --> main.rs:3:9
  |
3 | let _ = 'a'..'z';
  |         ^^^--^^^
  |            |
  |            help: use an inclusive range: `..=`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#almost_complete_range
  = note: `#[warn(clippy::almost_complete_range)]` 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 ('a'..'z') is almost certainly a typo meant to include all letters.

Code that is most likely wrong or useless. Warns by default.

How to fix it

Clippy does not fix this one automatically (its suggestion may change behaviour, so it only shows it). Change the code by hand:

Flagged

let _ = 'a'..'z';

Write this instead

let _ = 'a'..='z';

Turn it off, or on

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

On one item

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

Whole crate (Cargo.toml)

[lints.clippy]
almost_complete_range = "allow"

One run

cargo clippy -- -A clippy::almost-complete-range

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.

Settings in clippy.toml

msrv: The minimum rust version that the project supports. Defaults to the rust-version field in Cargo.toml

Suspiciousgroup

warndefault level

nofixed by cargo clippy --fix

1.68.0added in Rust

Clippy's own documentation

What it does

Checks for ranges which almost include the entire range of letters from ‘a’ to ‘z’ or digits from ‘0’ to ‘9’, but don’t because they’re a half open range.

Why is this bad?

This ('a'..'z') is almost certainly a typo meant to include all letters.

Example

let _ = 'a'..'z';

Use instead:

let _ = 'a'..='z';

Past names

almost_complete_letter_range

Configuration

msrv: The minimum rust version that the project supports. Defaults to the rust-version field in Cargo.toml

(default: current version)

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

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