Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::non_minimal_cfg: unneeded sub `cfg` when there is only one condition
What it meansChecks for any and all combinators in cfg with only one condition. It is in the style group and warns by default.
What you see
warning: unneeded sub `cfg` when there is only one condition --> main.rs:3:7 | 3 | #[cfg(any(unix))] | ^^^^^^^^^ help: try: `unix` | = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#non_minimal_cfg = note: `#[warn(clippy::non_minimal_cfg)]` 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?
If there is only one condition, no need to wrap it into any or all combinators.
Code that works but is not idiomatic Rust. Warns by default.
How to fix it
Clippy does not fix this one automatically (its suggestion may change behaviour, so it only shows it). Change the code by hand:
Flagged
#[cfg(any(unix))]
pub struct Bar;
Write this instead
#[cfg(unix)]
pub struct 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::non_minimal_cfg)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
non_minimal_cfg = "allow"One run
cargo clippy -- -A clippy::non-minimal-cfgThe [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
Checks for any and all combinators in cfg with only one condition.
Why is this bad?
If there is only one condition, no need to wrap it into any or all combinators.
Example
#[cfg(any(unix))]
pub struct Bar;
Use instead:
#[cfg(unix)]
pub struct Bar;
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
- neg_multiplyChecks for multiplication by -1 as a form of negation
- new_ret_no_selfChecks for new not returning a type that contains Self
- nonstandard_macro_bracesuse of irregular braces for `vec!` macro
- obfuscated_if_elsethis method chain can be written more clearly with `if .. else ..`
- ok_expectChecks for usage of ok().expect(..). Note: This lint only triggers for code marked compatible with versions of the compiler older than Rust 1.82.0
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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