Clippy lints / Complexity
Clippy lint · Complexity · checked with Clippy 0.1.99
clippy::bool_comparison: Checks for expressions of the form x == true, x != true and order comparisons such as x < true (or vice versa) and suggest using the variable directly
What it meansChecks for expressions of the form x == true, x != true and order comparisons such as x < true (or vice versa) and suggest using the variable directly. It is in the complexity group and warns by default.
Does it matter?
Unnecessary code.
Code that does something simple in a complicated way. 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
if x == true {}
if y == false {}
Write this instead
if x {}
if !y {}
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::bool_comparison)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
bool_comparison = "allow"One run
cargo clippy -- -A clippy::bool-comparisonThe [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 expressions of the form x == true,
x != true and order comparisons such as x < true (or vice versa) and
suggest using the variable directly.
Why is this bad?
Unnecessary code.
Example
if x == true {}
if y == false {}
use x directly:
if x {}
if !y {}
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
- too_many_argumentsChecks for functions with too many parameters
- clone_on_copyusing `clone` on type `u64` which implements the `Copy` trait
- type_complexityChecks for types used in structs, parameters and let declarations above a certain complexity threshold
- bind_instead_of_mapChecks for usage of _.and_then(|x| Some(y)), _.and_then(|x| Ok(y)) or _.or_else(|x| Err(y))
- borrow_deref_refderef on an immutable reference
- borrowed_boxChecks for usage of &Box<T> anywhere in the code. Check the Box documentation for more information
- bytes_count_to_lenusing long and hard to read `.bytes().count()`
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
Up next
Related lintclippy::too_many_argumentsChecks for functions with too many parametersRead it next →Did this answer your question?