Clippy lints / Restriction
Clippy lint · Restriction · checked with Clippy 0.1.99
clippy::non_ascii_literal: literal non-ASCII character detected
What it meansChecks for non-ASCII characters in string and char literals. It is in the restriction group and off by default.
What you see
warning: literal non-ASCII character detected --> main.rs:3:22 | 3 | let x = String::from("€"); | ^^^ help: consider replacing the string with: `"\u{20ac}"` | = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#non_ascii_literal = note: requested on the command line with `-W clippy::non-ascii-literal`
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?
Yeah, we know, the 90’s called and wanted their charset back. Even so, there still are editors and other programs out there that don’t work well with Unicode. So if the code is meant to be used internationally, on multiple operating systems, or has other portability requirements, activating this lint could be useful.
Lints that forbid language features for specific codebases (no unwrap, no indexing...). Off by default; pick them one by one, never the whole group.
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 = String::from("€");
Write this instead
let x = String::from("\u{20ac}");
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]
non_ascii_literal = "warn"In code
#![warn(clippy::non_ascii_literal)]One run
cargo clippy -- -W clippy::non-ascii-literalThe [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.
Clippy's own documentation
What it does
Checks for non-ASCII characters in string and char literals.
Why restrict this?
Yeah, we know, the 90’s called and wanted their charset back. Even so, there still are editors and other programs out there that don’t work well with Unicode. So if the code is meant to be used internationally, on multiple operating systems, or has other portability requirements, activating this lint could be useful.
Example
let x = String::from("€");
Use instead:
let x = String::from("\u{20ac}");
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
- unwrap_usedChecks for .unwrap() or .unwrap_err() calls on Results and .unwrap() call on Options
- module_name_repetitionsDetects public item names that are prefixed or suffixed by the containing public module’s name
- expect_usedChecks for .expect() or .expect_err() calls on Results and .expect() call on Options
- mutex_atomicChecks for usage of Mutex<X> where an atomic will do
- mutex_integerChecks for usage of Mutex<X> where X is an integral type
- needless_raw_stringsunnecessary raw string literal
- non_zero_suggestionsconsider using `NonZeroU64::from()` for more efficient and type-safe conversion
- panic`panic` should not be present in production code
- panic_in_result_fnused `panic!()` or assertion in a function that returns `Result`
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
Up next
Related lintclippy::unwrap_usedChecks for .unwrap() or .unwrap_err() calls on Results and .unwrap() call on OptionsRead it next →Did this answer your question?