Clippy lint · Restriction · checked with Clippy 0.1.99

clippy::inline_modules: inline module found

What it meansChecks that module layout does not use inline modules. Inline test modules (anything annotated with #[cfg(test)]) are not linted. It is in the restriction group and off by default.

What you see

warning: inline module found
 --> main.rs:4:1
  |
4 | / mod foo {
5 | |    /* module contents */
6 | | }
  | |_^
  |
  = help: move the contents of the module to `foo.rs` or `foo\mod.rs`, and replace this with `mod foo;`
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#inline_modules
  = note: requested on the command line with `-W clippy::inline-modules`

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?

Having multiple module layout styles in a project can be confusing.

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

// in `src/lib.rs`
mod foo {
   /* module contents */
}

Write this instead

// in `src/lib.rs`
mod foo;
// in `src/foo.rs` (or `src/foo/mod.rs`)
/* module contents */

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]
inline_modules = "warn"

In code

#![warn(clippy::inline_modules)]

One run

cargo clippy -- -W clippy::inline-modules

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

1.97.0added in Rust

Clippy's own documentation

What it does

Checks that module layout does not use inline modules. Inline test modules (anything annotated with #[cfg(test)]) are not linted.

Why restrict this?

Having multiple module layout styles in a project can be confusing.

Known problems

The lint currently doesn’t lint inline modules whose parent module is annotated with the #[path] attribute.

Example

// in `src/lib.rs`
mod foo {
   /* module contents */
}

Use instead:

// in `src/lib.rs`
mod foo;
// in `src/foo.rs` (or `src/foo/mod.rs`)
/* module contents */

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

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