Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::needless_parens_on_range_literals: needless parenthesis on range literals can be removed
What it meansThe lint checks for parenthesis on literals in range statements that are superfluous. It is in the style group and warns by default.
What you see
warning: needless parenthesis on range literals can be removed --> main.rs:3:10 | 3 | for i in (0)..10 { | ^^^ help: try: `0` | = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#needless_parens_on_range_literals = note: `#[warn(clippy::needless_parens_on_range_literals)]` 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?
Having superfluous parenthesis makes the code less readable overhead when reading.
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
for i in (0)..10 {
println!("{i}");
}
Write this instead
for i in 0..10 {
println!("{i}");
}
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::needless_parens_on_range_literals)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
needless_parens_on_range_literals = "allow"One run
cargo clippy -- -A clippy::needless-parens-on-range-literalsThe [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
The lint checks for parenthesis on literals in range statements that are superfluous.
Why is this bad?
Having superfluous parenthesis makes the code less readable overhead when reading.
Example
for i in (0)..10 {
println!("{i}");
}
Use instead:
for i in 0..10 {
println!("{i}");
}
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
- needless_doctest_mainChecks for fn main() {
- needless_elsethis `else` branch is empty
- needless_late_initunneeded late initialization
- needless_pub_selfunnecessary `pub(self)`
- needless_range_loopthe loop variable `i` is only used to index `vec`
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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