feat(manual_assert_eq): new lint #16025

ada4a · 2025-11-04T10:06:03Z

Resolves #13252
Resurrection of #13333

changelog: [manual_assert_eq]: new lint

rustbot · 2025-11-04T10:06:08Z

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github-actions · 2025-11-04T10:23:18Z

Lintcheck changes for ada768b

Lint	Added	Removed	Changed
`clippy::manual_assert_eq`	140	0	0

This comment will be updated if you push new changes

samueltardieu

The suggestion is only valid if the types being compared implement Debug.

View changes since this review

clippy_lints/src/manual_assert_eq.rs

ada4a · 2025-11-05T08:03:33Z

@rustbot ready

clippy_lints/src/manual_assert_eq.rs

Alexendoo · 2025-11-15T15:05:09Z

clippy_utils/src/ty/mod.rs

+    #[expect(
+        clippy::manual_assert_eq,
+        reason = "the message contains `assert_eq!`-like formatting itself"
+    )]


We shouldn't lint if there is an assert message provided

I agree that the suggestion is unfortunate in this case, but in general, a provided assert message can often complement the default one from assert_eq

Maybe reduce the applicability in this case?

Alexendoo · 2025-11-15T15:06:47Z

tests/ui/assertions_on_constants.rs

+    #[allow(clippy::manual_assert_eq, reason = "tests `assert!` specifically")]
+    {
+        assert!(8 == (7 + 1));
+        //~^ assertions_on_constants
+    }


The allows in this and other unrelated tests should go in the top level #![allow] like other lints, they don't need a reason

In my experience, putting such specific allows (and not things like no_effect, which one really wants to apply to the whole file) on the specific locations that trigger them helps keep the test suite clean, as it's easier to notice when a particular allow becomes unnecessary (this has happened to me more than once). Specifying a reason is also helpful for that.

Moving to expects is something we might want to consider to know when we need to cleanup, though that comes with its own problems

But I think having irrelevant lints inline is a distraction personally

Fine fine.. moved the allows to the top, switching to expect wherever possible

Alexendoo · 2025-12-02T19:03:05Z

Opened https://rust-lang.zulipchat.com/#narrow/channel/257328-clippy/topic/FCP.20manual_assert_eq/with/561497258

rustbot · 2026-01-16T23:00:32Z

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

rustbot assigned Alexendoo Nov 4, 2025

rustbot added needs-fcp S-waiting-on-review Status: Awaiting review from the assignee but also interested parties labels Nov 4, 2025

ada4a force-pushed the manual_assert_eq branch from be6ca8c to 4db706b Compare November 4, 2025 10:13

ada4a force-pushed the manual_assert_eq branch 5 times, most recently from 5856d0e to 7ae07b6 Compare November 4, 2025 13:38

samueltardieu requested changes Nov 5, 2025

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clippy_lints/src/manual_assert_eq.rs Outdated Show resolved Hide resolved

rustbot added S-waiting-on-author Status: This is awaiting some action from the author. (Use `@rustbot ready` to update this status) and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties labels Nov 5, 2025

ada4a force-pushed the manual_assert_eq branch from 7ae07b6 to 6b87ed6 Compare November 5, 2025 08:01

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties and removed S-waiting-on-author Status: This is awaiting some action from the author. (Use `@rustbot ready` to update this status) labels Nov 5, 2025