| ### What it does |
| Checks any kind of arithmetic operation of any type. |
| |
| Operators like `+`, `-`, `*` or `<<` are usually capable of overflowing according to the [Rust |
| Reference](https://doc.rust-lang.org/reference/expressions/operator-expr.html#overflow), |
| or can panic (`/`, `%`). |
| |
| Known safe built-in types like `Wrapping` or `Saturating`, floats, operations in constant |
| environments, allowed types and non-constant operations that won't overflow are ignored. |
| |
| ### Why is this bad? |
| For integers, overflow will trigger a panic in debug builds or wrap the result in |
| release mode; division by zero will cause a panic in either mode. As a result, it is |
| desirable to explicitly call checked, wrapping or saturating arithmetic methods. |
| |
| #### Example |
| ``` |
| // `n` can be any number, including `i32::MAX`. |
| fn foo(n: i32) -> i32 { |
| n + 1 |
| } |
| ``` |
| |
| Third-party types can also overflow or present unwanted side-effects. |
| |
| #### Example |
| ``` |
| use rust_decimal::Decimal; |
| let _n = Decimal::MAX + Decimal::MAX; |
| ``` |
| |
| ### Allowed types |
| Custom allowed types can be specified through the "arithmetic-side-effects-allowed" filter. |
