Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::manual_saturating_arithmetic: Checks for .checked_add/sub(x).unwrap_or(MAX/MIN)
What it meansChecks for .checked_add/sub(x).unwrap_or(MAX/MIN). It is in the style group and warns by default.
Does it matter?
These can be written simply with saturating_add/sub methods.
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
let add = x.checked_add(y).unwrap_or(u32::MAX);
let sub = x.checked_sub(y).unwrap_or(u32::MIN);
Write this instead
let add = x.saturating_add(y);
let sub = x.saturating_sub(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::manual_saturating_arithmetic)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
manual_saturating_arithmetic = "allow"One run
cargo clippy -- -A clippy::manual-saturating-arithmeticThe [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 .checked_add/sub(x).unwrap_or(MAX/MIN).
Why is this bad?
These can be written simply with saturating_add/sub methods.
Example
let add = x.checked_add(y).unwrap_or(u32::MAX);
let sub = x.checked_sub(y).unwrap_or(u32::MIN);
can be written using dedicated methods for saturating addition/subtraction as:
let add = x.saturating_add(y);
let sub = x.saturating_sub(y);
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
- manual_range_containsmanual `Range::contains` implementation
- manual_repeat_nthis `repeat().take()` can be written more concisely
- manual_rotatethere is no need to manually implement bit rotation
- manual_slice_fillmanually filling a slice
- manual_while_let_someyou seem to be trying to pop elements from a `Vec` in a loop
- map_cloneyou are using an explicit closure for copying elements
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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