Clippy lint · Restriction · checked with Clippy 0.1.99

clippy::assertions_on_result_states: Checks for assert!(r.is_ok()) or assert!(r.is_err()) calls

What it meansChecks for assert!(r.is_ok()) or assert!(r.is_err()) calls. It is in the restriction group and off by default.

Does it matter?

This form of assertion does not show any of the information present in the Result other than which variant it isn’t.

Lints that forbid language features for specific codebases (no unwrap, no indexing...). Off by default; pick them one by one, never the whole group.

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

assert!(r.is_ok());
assert!(r.is_err());

Write this instead

r.unwrap();
r.unwrap_err();

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]
assertions_on_result_states = "warn"

In code

#![warn(clippy::assertions_on_result_states)]

One run

cargo clippy -- -W clippy::assertions-on-result-states

The [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.

Restrictiongroup

allowdefault level

yesfixed by cargo clippy --fix

1.64.0added in Rust

Clippy's own documentation

What it does

Checks for assert!(r.is_ok()) or assert!(r.is_err()) calls.

Why restrict this?

This form of assertion does not show any of the information present in the Result other than which variant it isn’t.

Known problems

The suggested replacement decreases the readability of code and log output.

Example

assert!(r.is_ok());
assert!(r.is_err());

Use instead:

r.unwrap();
r.unwrap_err();

From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.

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