Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::needless_return: unneeded `return` statement
What it meansChecks for return statements at the end of a block. It is in the style group and warns by default.
What you see
warning: unneeded `return` statement --> main.rs:4:5 | 4 | return x; | ^^^^^^^^ | = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#needless_return = note: `#[warn(clippy::needless_return)]` on by default help: remove `return` | 4 - return x; 4 + x |
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?
Removing the return and semicolon will make the code more rusty.
Code that works but is not idiomatic Rust. Warns by default.
How to fix it
Clippy can fix this one for you: run cargo clippy --fix (add --allow-dirty if you have uncommitted changes). Review the diff before you commit.
Flagged
fn foo(x: usize) -> usize {
return x;
}
Write this instead
fn foo(x: usize) -> usize {
x
}
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::needless_return)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
needless_return = "allow"One run
cargo clippy -- -A clippy::needless-returnThe [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.
Clippy's own documentation
What it does
Checks for return statements at the end of a block.
Why is this bad?
Removing the return and semicolon will make the code
more rusty.
Example
fn foo(x: usize) -> usize {
return x;
}
simplify to
fn foo(x: usize) -> usize {
x
}
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
- new_without_defaultChecks for public types with a pub fn new() -> Self method and no implementation of Default
- len_zeroChecks for getting the length of something via .len() just to compare to zero, and suggests using .is_empty() where applicable
- needless_borrowthis expression creates a reference which is immediately dereferenced by the compiler
- needless_parens_on_range_literalsneedless parenthesis on range literals can be removed
- needless_pub_selfunnecessary `pub(self)`
- needless_range_loopthe loop variable `i` is only used to index `vec`
- needless_return_with_question_markChecks for return statements on Err paired with the ? operator
- neg_multiplyChecks for multiplication by -1 as a form of negation
- new_ret_no_selfChecks for new not returning a type that contains Self
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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