Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::chars_last_cmp: Checks for usage of _.chars().last() or _.chars().next_back() on a str to check if it ends with a given char
What it meansChecks for usage of _.chars().last() or _.chars().next_back() on a str to check if it ends with a given char. It is in the style group and warns by default.
Does it matter?
Readability, this can be written more concisely as _.ends_with(_).
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
name.chars().last() == Some('_') || name.chars().next_back() == Some('-');
Write this instead
name.ends_with('_') || name.ends_with('-');
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::chars_last_cmp)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
chars_last_cmp = "allow"One run
cargo clippy -- -A clippy::chars-last-cmpThe [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 usage of _.chars().last() or
_.chars().next_back() on a str to check if it ends with a given char.
Why is this bad?
Readability, this can be written more concisely as
_.ends_with(_).
Example
name.chars().last() == Some('_') || name.chars().next_back() == Some('-');
Use instead:
name.ends_with('_') || name.ends_with('-');
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
- builtin_type_shadowthis generic shadows the built-in type `u32`
- byte_char_slicescan be more succinctly written as a byte str
- bytes_nthcalled `.bytes().nth()` on a `str`
- chars_next_cmpyou should use the `starts_with` method
- chunks_exact_to_as_chunksusing `chunks_exact` with a constant chunk size
- cmp_nullThis lint checks for equality comparisons with ptr::null or ptr::null_mut
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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