DOUBLE_NEGATIONS in rustc_lint::builtin - Rust
Description: The `double_negations` lint detects expressions of the form `--x`.

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## DOUBLE_NEGATIONS

# Static DOUBLE_NEGATIONS

Source

    pub static DOUBLE_NEGATIONS: &Lint

Expand description

The `double_negations` lint detects expressions of the form `--x`.

#### §Example

    fn main() {
        let x = 1;
        let _b = --x;
    }

{{produces}}

#### §Explanation

Negating something twice is usually the same as not negating it at all. However, a double negation in Rust can easily be confused with the prefix decrement operator that exists in many languages derived from C. Use `-(-x)` if you really wanted to negate the value twice.

To decrement a value, use `x -= 1` instead.