[`unnecessary_safety_comment`] Some fixes regarding comments above attributes by teofr · Pull Request #15678 · rust-lang/rust-clippy

teofr · 2025-09-15T13:08:23Z

The way clippy checked for SAFETY comments above attributes was wrong:

It wasn't considered for items
It cause an ICE with some attributes
When considering comments above attributes, it didn't considered comments below them, causing some unlintable situations.

This PR tries to fix this by delegating the skipping of attributes to the function analyzing the source code itself.

changelog: [unnecessary_safety_comment]: Taking into account comments above attributes for items

github-actions · 2025-09-24T13:33:17Z

Lintcheck changes for 9cc0291

Lint	Added	Removed	Changed
`clippy::undocumented_unsafe_blocks`	0	18	1
`clippy::unnecessary_safety_comment`	16	0	269

This comment will be updated if you push new changes

teofr · 2025-09-24T14:58:29Z

I checked all the removed/added lints and they all make sense to me

All of the removed undocumented_unsafe_block are correct, and shouldn'te have been there in the first place
Most of the added unnecesary_safety_comment are because a // SAFETY: comment is used in an unsafe fn. Maybe we should improve the lint message in these cases to suggest a // # Safety comment instead
One is a SAFETY comment on a struct, which I think is correctly linted
One is a bug that's been uncovered by this PR but was present already (unnecessary_safety_comment and undocumented_unsafe_blocks visit the same comment twice #15755)
The changes are a bit strange, basically some notes regarding why the lint is enabled are deleted or added, does anyone know what could cause this?

rustbot · 2025-09-24T15:14:45Z

r? @samueltardieu

rustbot has assigned @samueltardieu.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

blyxyas · 2025-10-02T22:14:59Z

r? blyxyas

Being that this is R4L-oriented, I'll give it priority

blyxyas · 2025-10-02T23:57:31Z

Maybe we should improve the lint message in these cases to suggest a // # Safety comment instead

We totally should! could you add that case? (It should be simple)

blyxyas

Great patch, but I have one request.
It's a bit hard to distinguish why you're being prompted to remove a SAFETY comment from an unsafe function without extra help. What about not linting when that SAFETY comment comes from a doc-comment, as it will be rendered as useful information for consumers?

Also, if it's not a doc-comment, we can suggest to make it into a doc comment (/// # Safety)

View changes since this review

blyxyas · 2025-10-03T00:18:03Z

clippy_lints/src/undocumented_unsafe_blocks.rs

            Some((start + (text.len() - trimmed.len()), trimmed))
        })
-        .filter(|(_, text)| !text.is_empty());
+        .filter(|(_, text)| !(text.is_empty() || (accept_comment_above_attributes && is_attribute(text))));


I really like how you managed to do a solution so elegant.

Thanks! I really appreciate it

teofr · 2025-10-05T12:35:08Z

Hey, thanks for the review!

I tried to reach a (useful) middle grounds, if there's a SAFETY: comment over an unsafe function:

if it's a doc comment, I try to suggest the change (not very smart at the moment)
if it's a regular comment, I provide help indicating than a # Safety doc comment section could be better

I modified what position is used for the lint, so I don't need to find the position of SAFETY, which changes a lot (269) of lints. If this is discouraged or not worth for this fix I can bring back the original span, and just handle the suggestion cases by hand.

Anyways, I think this lint deserves a bigger refactor (I'd like to work on it, but have no time right now). #15755 and #clippy > broken lint: `undocumented_unsafe_blocks`

Let me know what you think

@rustbot ready

blyxyas

Just some minor changes and this should be ready!

View changes since this review

clippy_lints/src/undocumented_unsafe_blocks.rs

teofr · 2025-10-08T15:18:42Z

@rustbot ready

blyxyas

LGTM, thanks! ❤️
Could you squash these commits?

View changes since this review

improve coverage Considering comments above attributes for items Fixed the ICE and safety comments between attributes - No longer using attr.span() - ignoring attributes manually Improve error messages on unsafe fns

rustbot · 2025-10-14T21:24:11Z

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.

teofr · 2025-10-14T21:33:54Z

Squashed and rebased!

@blyxyas

teofr force-pushed the issue-14555 branch from 58710d2 to 874c3a7 Compare September 24, 2025 13:38

teofr marked this pull request as ready for review September 24, 2025 15:14

rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties label Sep 24, 2025

rustbot assigned samueltardieu Sep 24, 2025

teofr changed the title ~~[unnecessary_safety_comment] Considering comments above attributes for items~~ [unnecessary_safety_comment] Some fixes regarding comments above attributes Sep 26, 2025

rustbot assigned blyxyas and unassigned samueltardieu Oct 2, 2025

blyxyas added the G-Rust-for-Linux Issues related to Rust-for-Linux wants and bugfixes label Oct 2, 2025

blyxyas requested changes Oct 3, 2025

View reviewed changes

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 Oct 3, 2025

teofr force-pushed the issue-14555 branch from 294b1e0 to 64c9cc9 Compare October 5, 2025 02:22

This comment has been minimized.

Sign in to view

teofr force-pushed the issue-14555 branch 2 times, most recently from 90eee6e to 05d5c5d Compare October 5, 2025 11:59

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 Oct 5, 2025

This comment has been minimized.

Sign in to view

teofr force-pushed the issue-14555 branch from 05d5c5d to 5bd8cff Compare October 7, 2025 10:40

This comment has been minimized.

Sign in to view

blyxyas requested changes Oct 8, 2025

View reviewed changes

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

clippy_lints/src/undocumented_unsafe_blocks.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 Oct 8, 2025

teofr force-pushed the issue-14555 branch from 5bd8cff to 99c8d5d Compare October 8, 2025 15:16

This comment has been minimized.

Sign in to view

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 Oct 8, 2025

blyxyas approved these changes Oct 14, 2025

View reviewed changes

unnecessary_safety_comment fix an ICE and

9cc0291

improve coverage Considering comments above attributes for items Fixed the ICE and safety comments between attributes - No longer using attr.span() - ignoring attributes manually Improve error messages on unsafe fns

teofr force-pushed the issue-14555 branch from 99c8d5d to 9cc0291 Compare October 14, 2025 21:24

blyxyas added this pull request to the merge queue Oct 14, 2025

Merged via the queue into rust-lang:master with commit b26a1aa Oct 14, 2025
11 checks passed

rustbot removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties label Oct 14, 2025

ojeda mentioned this pull request Oct 15, 2025

Clippy wanted features & bugfixes Rust-for-Linux/linux#349

Open

73 tasks

teofr deleted the issue-14555 branch October 15, 2025 15:05

purplesyringa mentioned this pull request Oct 20, 2025

Regression: undocumented_unsafe_blocks false positive on a multi-line attribute between // SAFETY and unsafe #15915

Open

jdonszelmann mentioned this pull request Feb 23, 2026

Port #[feature] to the new attribute system rust-lang/rust#152985

Merged

Conversation

teofr commented Sep 15, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

github-actions bot commented Sep 24, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

teofr commented Sep 24, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

rustbot commented Sep 24, 2025

Uh oh!

blyxyas commented Oct 2, 2025

Uh oh!

blyxyas commented Oct 2, 2025

Uh oh!

blyxyas left a comment • edited by rustbot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

blyxyas Oct 3, 2025

Choose a reason for hiding this comment

Uh oh!

teofr Oct 5, 2025

Choose a reason for hiding this comment

Uh oh!

This comment has been minimized.

teofr commented Oct 5, 2025

Uh oh!

This comment has been minimized.

This comment has been minimized.

blyxyas left a comment • edited by rustbot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

This comment has been minimized.

teofr commented Oct 8, 2025

Uh oh!

blyxyas left a comment • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

rustbot commented Oct 14, 2025

Uh oh!

teofr commented Oct 14, 2025

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

teofr commented Sep 15, 2025 •

edited

Loading

github-actions bot commented Sep 24, 2025 •

edited

Loading

teofr commented Sep 24, 2025 •

edited

Loading

blyxyas left a comment •

edited by rustbot

Loading

blyxyas left a comment •

edited by rustbot

Loading

blyxyas left a comment •

edited

Loading