Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::default_instead_of_iter_empty: `std::iter::empty()` is the more idiomatic way
What it meansIt checks for std::iter::Empty::default() and suggests replacing it with std::iter::empty(). It is in the style group and warns by default.
What you see
warning: `std::iter::empty()` is the more idiomatic way --> main.rs:3:9 | 3 | let _ = std::iter::Empty::<usize>::default(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::iter::empty::<usize>()` | = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#default_instead_of_iter_empty = note: `#[warn(clippy::default_instead_of_iter_empty)]` 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?
std::iter::empty() is the more idiomatic way.
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
let _ = std::iter::Empty::<usize>::default();
let iter: std::iter::Empty<usize> = std::iter::Empty::default();
Write this instead
let _ = std::iter::empty::<usize>();
let iter: std::iter::Empty<usize> = std::iter::empty();
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::default_instead_of_iter_empty)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
default_instead_of_iter_empty = "allow"One run
cargo clippy -- -A clippy::default-instead-of-iter-emptyThe [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
It checks for std::iter::Empty::default() and suggests replacing it with
std::iter::empty().
Why is this bad?
std::iter::empty() is the more idiomatic way.
Example
let _ = std::iter::Empty::<usize>::default();
let iter: std::iter::Empty<usize> = std::iter::Empty::default();
Use instead:
let _ = std::iter::empty::<usize>();
let iter: std::iter::Empty<usize> = std::iter::empty();
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
- collapsible_ifChecks for nested if statements which can be collapsed by &&-combining their conditions
- collapsible_matchthis `match` can be collapsed into the outer `match`
- comparison_to_emptyChecks for comparing to an empty slice such as "" or [], and suggests using .is_empty() where applicable
- disallowed_fieldsDenies the configured fields in clippy.toml Note: Even though this lint is warn-by-default, it will only trigger if fields are defined in the clippy.toml file
- disallowed_macrosDenies the configured macros in clippy.toml Note: Even though this lint is warn-by-default, it will only trigger if macros are defined in the clippy.toml file
- disallowed_methodsDenies the configured methods and functions in clippy.toml Note: Even though this lint is warn-by-default, it will only trigger if methods are defined in the clippy.toml file
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
Up next
Related lintclippy::needless_returnunneeded `return` statementRead it next →Did this answer your question?