Clippy lints / Restriction
Clippy lint · Restriction · checked with Clippy 0.1.99
clippy::string_lit_chars_any: Checks for <string_lit>.chars().any(|i| i == c)
What it meansChecks for <string_lit>.chars().any(|i| i == c). It is in the restriction group and off by default.
Does it matter?
It’s significantly slower than using a pattern instead, like matches!(c, '\\' | '.' | '+'). Despite this being faster, this is not perf as this is pretty common, and is a rather nice way to check if a char is any in a set. In any case, this restriction lint is available for situations where that additional performance is absolutely necessary.
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
"\\.+*?()|[]{}^$#&-~".chars().any(|x| x == c);
Write this instead
matches!(c, '\\' | '.' | '+' | '*' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~');
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]
string_lit_chars_any = "warn"In code
#![warn(clippy::string_lit_chars_any)]One run
cargo clippy -- -W clippy::string-lit-chars-anyThe [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 <string_lit>.chars().any(|i| i == c).
Why is this bad?
It’s significantly slower than using a pattern instead, like
matches!(c, '\\' | '.' | '+').
Despite this being faster, this is not perf as this is pretty common, and is a rather nice
way to check if a char is any in a set. In any case, this restriction lint is available
for situations where that additional performance is absolutely necessary.
Example
"\\.+*?()|[]{}^$#&-~".chars().any(|x| x == c);
Use instead:
matches!(c, '\\' | '.' | '+' | '*' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~');
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
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- 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
- std_instead_of_coreused import from `std` instead of `core`
- str_to_string`to_string()` called on a `&str`
- string_addyou added something to a string. Consider using `String::push_str()` instead
- string_sliceindexing into a string may panic if the index is within a UTF-8 character
- suspicious_xor_used_as_pow`^` is not the exponentiation operator
- tests_outside_test_moduleTriggers when a testing function (marked with the #[test] attribute) isn’t inside a testing module (marked with #[cfg(test)])
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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