clippy::transmute_int_to_bool: transmute from a `u8` to a `bool`

What you see

warning: transmute from a `u8` to a `bool`
 --> main.rs:5:19
  |
5 |     let _: bool = std::mem::transmute(x); // where x: u8
  |                   ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x != 0`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#transmute_int_to_bool
  = note: `#[warn(clippy::transmute_int_to_bool)]` on by default

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?

This might result in an invalid in-memory representation of a bool.

Code that does something simple in a complicated way. Warns by default.

How to fix it

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

Flagged

let x = 1_u8;
unsafe {
    let _: bool = std::mem::transmute(x); // where x: u8
}

// should be:
let _: bool = x != 0;

Turn it off, or on

Allow it where it does not fit your code, as narrowly as you can:

#[allow(clippy::transmute_int_to_bool)]
fn my_function() { /* ... */ }

[lints.clippy]
transmute_int_to_bool = "allow"

cargo clippy -- -A clippy::transmute-int-to-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.