Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::single_component_path_imports: this import is redundant
What it meansChecking for imports with single component use path. It is in the style group and warns by default.
What you see
warning: this import is redundant --> main.rs:1:1 | 1 | use regex; | ^^^^^^^^^^ help: remove it entirely | = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#single_component_path_imports = note: `#[warn(clippy::single_component_path_imports)]` 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?
Import with single component use path such as use cratename; is not necessary, and thus should be removed.
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
use regex;
fn main() {
regex::Regex::new(r"^\d{4}-\d{2}-\d{2}$").unwrap();
}
Write this instead
fn main() {
regex::Regex::new(r"^\d{4}-\d{2}-\d{2}$").unwrap();
}
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::single_component_path_imports)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
single_component_path_imports = "allow"One run
cargo clippy -- -A clippy::single-component-path-importsThe [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
Checking for imports with single component use path.
Why is this bad?
Import with single component use path such as use cratename;
is not necessary, and thus should be removed.
Example
use regex;
fn main() {
regex::Regex::new(r"^\d{4}-\d{2}-\d{2}$").unwrap();
}
Better as
fn main() {
regex::Regex::new(r"^\d{4}-\d{2}-\d{2}$").unwrap();
}
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
- self_named_constructorsconstructor `foo` has the same name as the type
- should_implement_traitChecks for methods that should live in a trait implementation of a std trait (see llogiq’s blog post for further information) instead of an inherent implementation
- single_char_add_strWarns when using push_str/insert_str with a single-character string literal where push/insert with a char would work fine
- single_matchChecks for matches with a single arm where an if let will usually suffice. This intentionally does not lint if there are comments inside of the other arm, so as to allow the user to document why having another explicit pattern with an empty body is necessary, or because the comments need to be preserved for other reasons
- string_extend_charscalling `.extend(_.chars())`
- tabs_in_doc_commentsusing tabs in doc comments is not recommended
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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