Clippy lint · Restriction · checked with Clippy 0.1.99

clippy::integer_division: integer division

What it meansChecks for division of integers It is in the restriction group and off by default.

What you see

warning: integer division
 --> main.rs:3:9
  |
3 | let x = 3 / 2;
  |         ^^^^^
  |
  = help: division of integers may cause loss of precision. consider using floats
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#integer_division
  = note: requested on the command line with `-W clippy::integer-division`

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?

When outside of some very specific algorithms, integer division is very often a mistake because it discards the remainder.

Lints that forbid language features for specific codebases (no unwrap, no indexing...). Off by default; pick them one by one, never the whole group.

How to fix it

Clippy does not fix this one automatically. Change the code by hand:

Flagged

let x = 3 / 2;
println!("{}", x);

Write this instead

let x = 3f32 / 2f32;
println!("{}", x);

Turn it off, or on

It is off by default. To use it, set it to warn or deny:

Whole crate (Cargo.toml)

[lints.clippy]
integer_division = "warn"

In code

#![warn(clippy::integer_division)]

One run

cargo clippy -- -W clippy::integer-division

The [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.

Restrictiongroup

allowdefault level

nofixed by cargo clippy --fix

1.37.0added in Rust

Clippy's own documentation

What it does

Checks for division of integers

Why restrict this?

When outside of some very specific algorithms, integer division is very often a mistake because it discards the remainder.

Example

let x = 3 / 2;
println!("{}", x);

Use instead:

let x = 3f32 / 2f32;
println!("{}", x);

From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.

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