Clippy lint · Pedantic · checked with Clippy 0.1.99

clippy::match_bool: Checks for matches where match expression is a bool

What it meansChecks for matches where match expression is a bool. It suggests to replace the expression with an if...else block. It is in the pedantic group and off by default.

Does it matter?

It makes the code less readable.

Stricter lints with some false positives. Off by default; opt in with clippy::pedantic.

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 condition: bool = true;
match condition {
    true => foo(),
    false => bar(),
}

Write this instead

let condition: bool = true;
if condition {
    foo();
} else {
    bar();
}

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]
match_bool = "warn"

In code

#![warn(clippy::match_bool)]

One run

cargo clippy -- -W clippy::match-bool

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.

Pedanticgroup

allowdefault level

yesfixed by cargo clippy --fix

pre 1.29.0added in Rust

Clippy's own documentation

What it does

Checks for matches where match expression is a bool. It suggests to replace the expression with an if...else block.

Why is this bad?

It makes the code less readable.

Example

let condition: bool = true;
match condition {
    true => foo(),
    false => bar(),
}

Use if/else instead:

let condition: bool = true;
if condition {
    foo();
} else {
    bar();
}

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

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