Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::println_empty_string: empty string literal in `println!`
What it meansThis lint warns when you use println!("") to print a newline. It is in the style group and warns by default.
What you see
warning: empty string literal in `println!` --> main.rs:3:1 | 3 | println!(""); | ^^^^^^^^^--^ | | | help: remove the empty string | = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#println_empty_string = note: `#[warn(clippy::println_empty_string)]` 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?
You should use println!(), which is simpler.
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
println!("");
Write this instead
println!();
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::println_empty_string)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
println_empty_string = "allow"One run
cargo clippy -- -A clippy::println-empty-stringThe [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
This lint warns when you use println!("") to
print a newline.
Why is this bad?
You should use println!(), which is simpler.
Example
println!("");
Use instead:
println!();
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
- needless_returnunneeded `return` statement
- 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
- partialeq_to_nonebinary comparison to literal `Option::None`
- print_literalliteral with an empty format string
- print_with_newlineThis lint warns when you use print!() with a format string that ends in a newline
- ptr_argThis lint checks for function arguments of type &String, &Vec, &PathBuf, and Cow<_>
- ptr_equse `std::ptr::eq` when comparing raw pointers
- question_markChecks for expressions that could be replaced by the ? operator
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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