Clippy lint · Style · checked with Clippy 0.1.99

clippy::main_recursion: recursing into entrypoint `main`

What it meansChecks for recursion using the entrypoint. It is in the style group and warns by default.

What you see

warning: recursing into entrypoint `main`
 --> main.rs:2:5
  |
2 |     main();
  |     ^^^^
  |
  = help: consider using another function for this recursion
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#main_recursion
  = note: `#[warn(clippy::main_recursion)]` 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?

Apart from special setups (which we could detect following attributes like #![no_std]), recursing into main() seems like an unintuitive anti-pattern we should be able to detect.

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

How to fix it

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

Flagged

fn main() {
    main();
}

Turn it off, or on

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

On one item

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

Whole crate (Cargo.toml)

[lints.clippy]
main_recursion = "allow"

One run

cargo clippy -- -A clippy::main-recursion

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.

Stylegroup

warndefault level

nofixed by cargo clippy --fix

1.38.0added in Rust

Clippy's own documentation

What it does

Checks for recursion using the entrypoint.

Why is this bad?

Apart from special setups (which we could detect following attributes like #![no_std]), recursing into main() seems like an unintuitive anti-pattern we should be able to detect.

Example

fn main() {
    main();
}

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

Up next

Also worth your time

Did this answer your question?