Clippy lints / Correctness
Clippy lint · Correctness · checked with Clippy 0.1.99
clippy::erasing_op: this operation will always return zero. This is likely not the intended outcome
What it meansChecks for erasing operations, e.g., x * 0. It is in the correctness group and denied by default (the build fails).
What you see
error: this operation will always return zero. This is likely not the intended outcome --> main.rs:4:1 | 4 | 0 / x; | ^^^^^ | = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#erasing_op = note: `#[deny(clippy::erasing_op)]` 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?
The whole expression can be replaced by zero. This is most likely not the intended outcome and should probably be corrected
Code that is almost certainly wrong. Denied by default: the build fails until you fix it or allow it.
How to fix it
Clippy does not fix this one automatically. Change the code by hand:
Flagged
let x = 1;
0 / x;
0 * x;
x & 0;
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::erasing_op)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
erasing_op = "allow"One run
cargo clippy -- -A clippy::erasing-opThe [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 erasing operations, e.g., x * 0.
Why is this bad?
The whole expression can be replaced by zero. This is most likely not the intended outcome and should probably be corrected
Example
let x = 1;
0 / x;
0 * x;
x & 0;
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
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- enum_clike_unportable_variantC-like enum variant discriminant is not portable to 32-bit targets
- eq_opChecks for equal operands to comparison, logical and bitwise, difference and division binary operators (==, >, etc., &&, ||, &, |, ^, - and /)
- if_let_mutexChecks for Mutex::lock calls in if let expression with lock calls in any of the else blocks
- ifs_same_condChecks for consecutive ifs with the same condition
- impl_hash_borrow_with_str_and_bytesthe semantics of `Borrow<T>` around `Hash` can't be satisfied when both `Borrow<str>` and `Borrow<[u8]>` are implemented
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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