Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::cmp_null: This lint checks for equality comparisons with ptr::null or ptr::null_mut
What it meansThis lint checks for equality comparisons with ptr::null or ptr::null_mut It is in the style group and warns by default.
Does it matter?
It’s easier and more readable to use the inherent .is_null() method instead
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 std::ptr;
if x == ptr::null() {
// ..
}
Write this instead
if x.is_null() {
// ..
}
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::cmp_null)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
cmp_null = "allow"One run
cargo clippy -- -A clippy::cmp-nullThe [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 checks for equality comparisons with ptr::null or ptr::null_mut
Why is this bad?
It’s easier and more readable to use the inherent
.is_null()
method instead
Example
use std::ptr;
if x == ptr::null() {
// ..
}
Use instead:
if x.is_null() {
// ..
}
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
- chars_last_cmpChecks for usage of _.chars().last() or _.chars().next_back() on a str to check if it ends with a given char
- chars_next_cmpyou should use the `starts_with` method
- chunks_exact_to_as_chunksusing `chunks_exact` with a constant chunk size
- 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
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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