Clippy lint · Complexity · checked with Clippy 0.1.99

clippy::explicit_write: Checks for usage of write!() / writeln()! which can be replaced with (e)print!() / (e)println!()

What it meansChecks for usage of write!() / writeln()! which can be replaced with (e)print!() / (e)println!() It is in the complexity group and warns by default.

Does it matter?

Using (e)println! is clearer and more concise

Code that does something simple in a complicated way. 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

writeln!(&mut std::io::stderr(), "foo: {:?}", bar).unwrap();
writeln!(&mut std::io::stdout(), "foo: {:?}", bar).unwrap();

Write this instead

eprintln!("foo: {:?}", bar);
println!("foo: {:?}", bar);

Turn it off, or on

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

On one item

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

Whole crate (Cargo.toml)

[lints.clippy]
explicit_write = "allow"

One run

cargo clippy -- -A clippy::explicit-write

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.

Complexitygroup

warndefault level

yesfixed by cargo clippy --fix

pre 1.29.0added in Rust

Clippy's own documentation

What it does

Checks for usage of write!() / writeln()! which can be replaced with (e)print!() / (e)println!()

Why is this bad?

Using (e)println! is clearer and more concise

Example

writeln!(&mut std::io::stderr(), "foo: {:?}", bar).unwrap();
writeln!(&mut std::io::stdout(), "foo: {:?}", bar).unwrap();

Use instead:

eprintln!("foo: {:?}", bar);
println!("foo: {:?}", bar);

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

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