Clippy lints / Pedantic
Clippy lint · Pedantic · checked with Clippy 0.1.99
clippy::should_panic_without_expect: Checks for #[should_panic] attributes without specifying the expected panic message
What it meansChecks for #[should_panic] attributes without specifying the expected panic message. It is in the pedantic group and off by default.
Does it matter?
The expected panic message should be specified to ensure that the test is actually panicking with the expected message, and not another unrelated panic.
Stricter lints with some false positives. Off by default; opt in with clippy::pedantic.
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
fn random() -> i32 { 0 }
#[should_panic]
#[test]
fn my_test() {
let _ = 1 / random();
}
Write this instead
fn random() -> i32 { 0 }
#[should_panic = "attempt to divide by zero"]
#[test]
fn my_test() {
let _ = 1 / random();
}
Turn it off, or on
It is off by default. To use it, set it to warn or deny:
Whole crate (Cargo.toml)
[lints.clippy]
should_panic_without_expect = "warn"In code
#![warn(clippy::should_panic_without_expect)]One run
cargo clippy -- -W clippy::should-panic-without-expectThe [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 #[should_panic] attributes without specifying the expected panic message.
Why is this bad?
The expected panic message should be specified to ensure that the test is actually panicking with the expected message, and not another unrelated panic.
Example
fn random() -> i32 { 0 }
#[should_panic]
#[test]
fn my_test() {
let _ = 1 / random();
}
Use instead:
fn random() -> i32 { 0 }
#[should_panic = "attempt to divide by zero"]
#[test]
fn my_test() {
let _ = 1 / random();
}
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
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All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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