Clippy lints / Pedantic
Clippy lint · Pedantic · checked with Clippy 0.1.99
clippy::semicolon_if_nothing_returned: consider adding a `;` to the last statement for consistent formatting
What it meansLooks for blocks of expressions and fires if the last expression returns () but is not followed by a semicolon. It is in the pedantic group and off by default.
What you see
warning: consider adding a `;` to the last statement for consistent formatting --> main.rs:2:5 | 2 | println!("Hello world") | ^^^^^^^^^^^^^^^^^^^^^^^ help: add a `;` here: `println!("Hello world");` | = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#semicolon_if_nothing_returned = note: `-W clippy::semicolon-if-nothing-returned` implied by `-W clippy::pedantic`
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?
The semicolon might be optional but when extending the block with new code, it doesn’t require a change in previous last line.
Stricter lints with some false positives. Off by default; opt in with clippy::pedantic.
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 main() {
println!("Hello world")
}
Write this instead
fn main() {
println!("Hello world");
}
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]
semicolon_if_nothing_returned = "warn"In code
#![warn(clippy::semicolon_if_nothing_returned)]One run
cargo clippy -- -W clippy::semicolon-if-nothing-returnedThe [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
Looks for blocks of expressions and fires if the last expression returns
() but is not followed by a semicolon.
Why is this bad?
The semicolon might be optional but when extending the block with new code, it doesn’t require a change in previous last line.
Example
fn main() {
println!("Hello world")
}
Use instead:
fn main() {
println!("Hello world");
}
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
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- same_length_and_capacityChecks for usages of Vec::from_raw_parts and String::from_raw_parts where the same expression is used for the length and the capacity
- self_only_used_in_recursion`self` is only used in recursion
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- similar_namesbinding's name is too similar to existing binding
- single_char_patternChecks for string methods that receive a single-character str as an argument, e.g., _.split("x")
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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