clippy::manual_non_exhaustive: Checks for manual implementations of the non-exhaustive pattern

Does it matter?

Using the #[non_exhaustive] attribute expresses better the intent and allows possible optimizations when applied to enums.

Code that works but is not idiomatic Rust. Warns by default.

How to fix it

Clippy does not fix this one automatically (its suggestion may change behaviour, so it only shows it). Change the code by hand:

Flagged

struct S {
    pub a: i32,
    pub b: i32,
    _c: (),
}

enum E {
    A,
    B,
    #[doc(hidden)]
    _C,
}

struct T(pub i32, pub i32, ());

Write this instead

#[non_exhaustive]
struct S {
    pub a: i32,
    pub b: i32,
}

#[non_exhaustive]
enum E {
    A,
    B,
}

#[non_exhaustive]
struct T(pub i32, pub i32);

Turn it off, or on

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

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

[lints.clippy]
manual_non_exhaustive = "allow"

cargo clippy -- -A clippy::manual-non-exhaustive

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.

Settings in clippy.toml

• msrv: The minimum rust version that the project supports. Defaults to the rust-version field in Cargo.toml