Clippy lints / Complexity
Clippy lint · Complexity · checked with Clippy 0.1.99
clippy::precedence: Checks for operations where precedence may be unclear and suggests to add parentheses. It catches a mixed usage of arithmetic and bit shifting/combining operators, as well as method calls applied to closures
What it meansChecks for operations where precedence may be unclear and suggests to add parentheses. It catches a mixed usage of arithmetic and bit shifting/combining operators, as well as method calls applied to closures. It is in the complexity group and warns by default.
Does it matter?
Not everyone knows the precedence of those operators by heart, so expressions like these may trip others trying to reason about the 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.
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::precedence)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
precedence = "allow"One run
cargo clippy -- -A clippy::precedenceThe [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 operations where precedence may be unclear and suggests to add parentheses. It catches a mixed usage of arithmetic and bit shifting/combining operators, as well as method calls applied to closures.
Why is this bad?
Not everyone knows the precedence of those operators by heart, so expressions like these may trip others trying to reason about the code.
Example
1 << 2 + 3 equals 32, while (1 << 2) + 3 equals 7
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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- 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
- option_map_unit_fnChecks for usage of option.map(f) where f is a function or closure that returns the unit type ()
- or_then_unwrapChecks for .or(…).unwrap() calls to Options and Results
- partialeq_ne_implre-implementing `PartialEq::ne` is unnecessary
- ptr_offset_with_castuse of `offset` with a `usize` cast to an `isize`
- range_zip_with_lenChecks for zipping a collection with the range of 0.._.len()
- redundant_as_strChecks for usage of as_str() on a String chained with a method available on the String itself
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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