Clean up `AttributeLintKind` and refactor diagnostic attribute linting by mejrs · Pull Request #155215 · rust-lang/rust

mejrs · 2026-04-12T21:45:04Z

There was a fair amount of duplication here, and thanks to the proliferation of new diagnostic attributes these days, it was threatening to grow bigger.

rustbot · 2026-04-12T21:45:09Z

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann, @JonathanBrouwer

rustbot · 2026-04-12T21:45:11Z

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rustbot · 2026-04-12T21:54:17Z

The Miri subtree was changed

cc @rust-lang/miri

rustbot · 2026-04-12T22:00:13Z

This PR was rebased onto a different main 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.

mejrs · 2026-04-13T22:17:06Z

@rustbot label -WG-trait-system-refactor

JonathanBrouwer · 2026-04-14T20:13:24Z

-                        span,
-                    );
-                }
+            if matches!(mode, Mode::RustcOnUnimplemented) {


I don't really like matches! here because if we ever add another rustc diagnostic attribute, we could forget to check it. How about a method mode.should_error(), that has an exhaustive match in it?

View changes since the review

It doesn't actually matter, assuming we don't ship a std that compiles with warnings?

So far my decisions on whether rustc_on_unimplemented errors or issues a diagnostic namespace lint have been largely focused on keeping the implementation simple:

erroring is easier than adding AttributeLintKind variants

so hard error in rustc_on_unimplemented-only paths to simplify there

issue lints in shared paths so you don't have to care about which attr it is

In fact, maybe this should just be a warning regardless?

That mentality also sounds reasonable to me, lets make this a warning to keep the implementation simple

I think I remember why it is this way, I applied the suggestion and then I got annoyed because

LL | #[rustc_on_unimplemented(lorem = "")] | ^^^^^^^^^^ invalid option found here | = help: only `message`, `note` and `label` are allowed as options

is not quite right.

The last commit fixes that by letting you customize the "allowed options" list per attribute. Note that I'm inclined to have an attribute with only "note" allowed, (#155200 (comment)) so we will need some kind of customization (or more lint variants) anyway.

Let me know what you think about the last few commits, idm backing it out if you prefer.

Seems reasonable, especially since we need this in the future :)

JonathanBrouwer

r=me with nit fixed
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rust-bors · 2026-04-14T20:14:03Z

✌️ @mejrs, you can now approve this pull request!

If @JonathanBrouwer told you to "r=me" after making some further change, then please make that change and post @bors r=JonathanBrouwer.

JonathanBrouwer · 2026-04-15T19:13:02Z

@bors r+ rollup

rust-bors · 2026-04-15T19:13:06Z

📌 Commit d6bccac has been approved by JonathanBrouwer

It is now in the queue for this repository.

…hanBrouwer Clean up `AttributeLintKind` and refactor diagnostic attribute linting There was a fair amount of duplication here, and thanks to the proliferation of new diagnostic attributes these days, it was threatening to grow bigger.

Rollup of 18 pull requests Successful merges: - #154595 (Emit fatal on invalid const args with nested defs) - #154599 (report the `varargs_without_pattern` lint in deps) - #154699 (`core::unicode`: Replace `Cased` table with `Lt`) - #155353 (resolve: Remove `inaccessible_ctor_reexport` resolver field) - #155357 (Add `--remap-path-scope` as unstable in rustdoc) - #150649 (clippy fix: non_canonical_clone_impl) - #154604 (abort in core) - #154616 (Add `--quiet` flag to x.py and bootstrap to suppress output) - #154970 (rustdoc: preserve `doc(cfg)` on locally re-exported type aliases) - #155215 (Clean up `AttributeLintKind` and refactor diagnostic attribute linting) - #155228 (Check diagnostic output in incremental `cpass` and `rpass` revisions) - #155266 (Adjust release notes for post-merge feedback) - #155326 (Disallow ZST allocations with `TypedArena`.) - #155334 (docs: Use `0b1` instead of `NonZero::MIN` in `NonZero::bit_width` doctests) - #155340 (Handle nonnull pattern types in size skeleton) - #155347 (Add push_mut and new Layout methods to release notes) - #155356 (remove calls to AliasTyKind::def_id) - #155364 (Reduce diagnostic type visibilities.)

Rollup of 18 pull requests Successful merges: - #154451 (Require that a `<_ as Try>::Residual` implement the `Residual` trait) - #154595 (Emit fatal on invalid const args with nested defs) - #154599 (report the `varargs_without_pattern` lint in deps) - #154699 (`core::unicode`: Replace `Cased` table with `Lt`) - #155353 (resolve: Remove `inaccessible_ctor_reexport` resolver field) - #155357 (Add `--remap-path-scope` as unstable in rustdoc) - #150649 (clippy fix: non_canonical_clone_impl) - #154604 (abort in core) - #154616 (Add `--quiet` flag to x.py and bootstrap to suppress output) - #155215 (Clean up `AttributeLintKind` and refactor diagnostic attribute linting) - #155228 (Check diagnostic output in incremental `cpass` and `rpass` revisions) - #155266 (Adjust release notes for post-merge feedback) - #155326 (Disallow ZST allocations with `TypedArena`.) - #155334 (docs: Use `0b1` instead of `NonZero::MIN` in `NonZero::bit_width` doctests) - #155340 (Handle nonnull pattern types in size skeleton) - #155347 (Add push_mut and new Layout methods to release notes) - #155356 (remove calls to AliasTyKind::def_id) - #155364 (Reduce diagnostic type visibilities.)

Rollup merge of #155215 - mejrs:condense_diag_lints, r=JonathanBrouwer Clean up `AttributeLintKind` and refactor diagnostic attribute linting There was a fair amount of duplication here, and thanks to the proliferation of new diagnostic attributes these days, it was threatening to grow bigger.

mejrs added 4 commits April 12, 2026 20:39

Merge malformed diagnostic attribute lint

e9d0e32

Merge "missing options" lints for diagnostic attributes

57fd974

move list parsing into its own function

217c073

Delete unused AttributeLintKind variant

0dd591a

rustbot added A-attributes Area: Attributes (`#[…]`, `#![…]`) S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Apr 12, 2026

rustbot assigned JohnTitor Apr 12, 2026

mejrs force-pushed the condense_diag_lints branch from 0dd591a to a4e8640 Compare April 12, 2026 21:54

rustbot added the WG-trait-system-refactor The Rustc Trait System Refactor Initiative (-Znext-solver) label Apr 12, 2026

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mejrs force-pushed the condense_diag_lints branch from a4e8640 to 0dd591a Compare April 12, 2026 22:00

Format the duplicate macro

f468cef

rustbot removed the WG-trait-system-refactor The Rustc Trait System Refactor Initiative (-Znext-solver) label Apr 13, 2026

JonathanBrouwer assigned JonathanBrouwer and unassigned JohnTitor Apr 14, 2026

JonathanBrouwer reviewed Apr 14, 2026

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JonathanBrouwer approved these changes Apr 14, 2026

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mejrs added 2 commits April 14, 2026 23:37

Warn instead of error for some ructs_on_unimplemented errors

75273e2

Pass allowed options as parameter to diagnostic lints

72db94f

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mejrs force-pushed the condense_diag_lints branch from 79d2d9a to 103adaa Compare April 15, 2026 10:36

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Fix error code example

d6bccac

mejrs force-pushed the condense_diag_lints branch from 103adaa to d6bccac Compare April 15, 2026 11:50

rust-bors bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Apr 15, 2026

jhpratt mentioned this pull request Apr 16, 2026

Rollup of 18 pull requests #155373

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jhpratt mentioned this pull request Apr 16, 2026

Rollup of 18 pull requests #155380

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rust-bors bot merged commit 0d98e0d into rust-lang:main Apr 16, 2026
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