Clippy lint · Complexity · checked with Clippy 0.1.99

clippy::transmute_int_to_non_zero: Checks for transmutes from T to NonZero<T>, and suggests the new_unchecked method instead

What it meansChecks for transmutes from T to NonZero<T>, and suggests the new_unchecked method instead. It is in the complexity group and warns by default.

Does it matter?

Transmutes work on any types and thus might cause unsoundness when those types change elsewhere. new_unchecked only works for the appropriate types instead.

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 _: NonZero<u32> = unsafe { std::mem::transmute(123) };

Write this instead

let _: NonZero<u32> = unsafe { NonZero::new_unchecked(123) };

Turn it off, or on

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

On one item

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

Whole crate (Cargo.toml)

[lints.clippy]
transmute_int_to_non_zero = "allow"

One run

cargo clippy -- -A clippy::transmute-int-to-non-zero

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.

Complexitygroup

warndefault level

nofixed by cargo clippy --fix

1.69.0added in Rust

Clippy's own documentation

What it does

Checks for transmutes from T to NonZero<T>, and suggests the new_unchecked method instead.

Why is this bad?

Transmutes work on any types and thus might cause unsoundness when those types change elsewhere. new_unchecked only works for the appropriate types instead.

Example

let _: NonZero<u32> = unsafe { std::mem::transmute(123) };

Use instead:

let _: NonZero<u32> = unsafe { NonZero::new_unchecked(123) };

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

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