Clippy lint · Restriction · checked with Clippy 0.1.99

clippy::missing_trait_methods: Checks if a provided method is used implicitly by a trait implementation

What it meansChecks if a provided method is used implicitly by a trait implementation. It is in the restriction group and off by default.

Does it matter?

To ensure that a certain implementation implements every method; for example, a wrapper type where every method should delegate to the corresponding method of the inner type’s implementation. This lint should typically be enabled on a specific trait impl item rather than globally.

Lints that forbid language features for specific codebases (no unwrap, no indexing...). Off by default; pick them one by one, never the whole group.

How to fix it

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

Flagged

trait Trait {
    fn required();

    fn provided() {}
}

#[warn(clippy::missing_trait_methods)]
impl Trait for Type {
    fn required() { /* ... */ }
}

Write this instead

trait Trait {
    fn required();

    fn provided() {}
}

#[warn(clippy::missing_trait_methods)]
impl Trait for Type {
    fn required() { /* ... */ }

    fn provided() { /* ... */ }
}

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]
missing_trait_methods = "warn"

In code

#![warn(clippy::missing_trait_methods)]

One run

cargo clippy -- -W clippy::missing-trait-methods

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.

Restrictiongroup

allowdefault level

nofixed by cargo clippy --fix

1.66.0added in Rust

Clippy's own documentation

What it does

Checks if a provided method is used implicitly by a trait implementation.

Why restrict this?

To ensure that a certain implementation implements every method; for example, a wrapper type where every method should delegate to the corresponding method of the inner type’s implementation.

This lint should typically be enabled on a specific trait impl item rather than globally.

Example

trait Trait {
    fn required();

    fn provided() {}
}

#[warn(clippy::missing_trait_methods)]
impl Trait for Type {
    fn required() { /* ... */ }
}

Use instead:

trait Trait {
    fn required();

    fn provided() {}
}

#[warn(clippy::missing_trait_methods)]
impl Trait for Type {
    fn required() { /* ... */ }

    fn provided() { /* ... */ }
}

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

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