Simplify `parse_limited` by JonathanBrouwer · Pull Request #155447 · rust-lang/rust

JonathanBrouwer · 2026-04-17T14:56:05Z

Removes unnecessary arguments from parse_limited and cleans up feature gating of on_unknown_attr

mejrs · 2026-04-17T18:20:28Z

+        {
            // `UnknownDiagnosticAttribute` is emitted in rustc_resolve/macros.rs
            return;
        }


There are a couple of rustc_resolve types that have a pub on_unknown_attr: Option<OnUnknownData> field.

This change makes it so they can be Some even if the feature is not used. The reason you aren't noticing it is because of this check at the use site:

rust/compiler/rustc_resolve/src/imports.rs

Lines 849 to 851 in 4dbafc3

let (message, label, notes) = if self.tcx.features().diagnostic_on_unknown()

&& let Some(directive) = errors[0].1.on_unknown_attr.as_ref().map(|a| &a.directive)

{

I'm on the fence whether it's worth the effort to "fix" this. But I would like some comments here and there to document whatever we end up with.

View changes since the review

I've moved the feature gating to the initialization of on_unknown_attr, and added some comments

rustbot · 2026-04-18T09:29:12Z

Some changes occurred to diagnostic attributes.

cc @mejrs

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann

rustbot · 2026-04-18T09:29:14Z

r? @JohnTitor

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JonathanBrouwer · 2026-04-18T09:29:25Z

r? @mejrs

mejrs

r=me with either check inverted or unchanged perf run results

View changes since this review

JonathanBrouwer · 2026-04-18T13:05:03Z

@bors try @rust-timer queue

Simplify `parse_limited`

rust-bors · 2026-04-18T15:15:29Z

☀️ Try build successful (CI)
Build commit: 3a904ef (3a904ef4079a69d50808d3bf162da01e6f6576e0, parent: 8da2d28cbd5a4e2b93e028e709afe09541671663)

rust-timer · 2026-04-18T16:29:32Z

Finished benchmarking commit (3a904ef): comparison URL.

Overall result: no relevant changes - no action needed

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

@bors rollup=never
@rustbot label: -S-waiting-on-perf -perf-regression

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Bootstrap: 493.313s -> 493.585s (0.06%)
Artifact size: 394.36 MiB -> 394.37 MiB (0.00%)

rustbot · 2026-04-18T17:15:55Z

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.

JonathanBrouwer · 2026-04-18T17:16:12Z

@bors r=mejrs rollup

rust-bors · 2026-04-18T17:16:15Z

📌 Commit e0d7848 has been approved by mejrs

It is now in the queue for this repository.

…ited, r=mejrs Simplify `parse_limited` Removes unnecessary arguments from `parse_limited` and cleans up feature gating of `on_unknown_attr`

…uwer Rollup of 10 pull requests Successful merges: - #150230 (spec next chunk for trustedlen) - #155284 (net::tcp/udp: fix docs about how set_nonblocking is implemented) - #146870 (fix: add aliasing rules for Box) - #154003 (Make std::fs::File Send on UEFI) - #155187 (std: fix HashMap RNG docs wording) - #155255 (Document why `layout.align() + layout.size()` doesn't overflow) - #155351 (Reorganize tests from `tests/ui/issues/`) - #155406 (std: Update dependency on `wasi` crate) - #155447 (Simplify `parse_limited`) - #155481 (Delete `SizeSkeleton::Generic`)

Rollup merge of #155447 - JonathanBrouwer:simplify-parse-limited, r=mejrs Simplify `parse_limited` Removes unnecessary arguments from `parse_limited` and cleans up feature gating of `on_unknown_attr`

rustbot added A-attributes Area: Attributes (`#[…]`, `#![…]`) S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Apr 17, 2026

petrochenkov reviewed Apr 17, 2026

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Comment thread compiler/rustc_attr_parsing/src/interface.rs Outdated

JonathanBrouwer changed the title ~~Simplify parse_limited and cleanup more attribute parsing~~ Simplify parse_limited Apr 17, 2026

JonathanBrouwer force-pushed the simplify-parse-limited branch from 25d63eb to 8bc2d3c Compare April 17, 2026 15:31

mejrs reviewed Apr 17, 2026

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JonathanBrouwer force-pushed the simplify-parse-limited branch from 8bc2d3c to a5d0719 Compare April 18, 2026 09:18

JonathanBrouwer marked this pull request as ready for review April 18, 2026 09:29

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 (such as code changes or more information) from the author. labels Apr 18, 2026

rustbot assigned JohnTitor Apr 18, 2026

rustbot assigned mejrs and unassigned JohnTitor Apr 18, 2026

mejrs reviewed Apr 18, 2026

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Comment thread compiler/rustc_resolve/src/imports.rs

Comment thread compiler/rustc_resolve/src/imports.rs Outdated

mejrs added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Apr 18, 2026

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rust-bors bot pushed a commit that referenced this pull request Apr 18, 2026

Auto merge of #155447 - JonathanBrouwer:simplify-parse-limited, r=<try>

3a904ef

Simplify `parse_limited`

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rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Apr 18, 2026

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Apr 18, 2026

JonathanBrouwer added 3 commits April 18, 2026 19:13

Remove target arguments & features from parse_limited

c5f6afc

Clarify and make consistent the feature gating of on_unknown_attr

5fe1e44

Fix rebox of directive

e0d7848

JonathanBrouwer force-pushed the simplify-parse-limited branch from a5d0719 to e0d7848 Compare April 18, 2026 17:15

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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Apr 18, 2026

This was referenced Apr 18, 2026

Rollup of 10 pull requests #155492

Closed

Rollup of 10 pull requests #155494

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rust-bors bot merged commit c165777 into rust-lang:main Apr 18, 2026
11 checks passed

rustbot added this to the 1.97.0 milestone Apr 18, 2026

	let (message, label, notes) = if self.tcx.features().diagnostic_on_unknown()
	&& let Some(directive) = errors[0].1.on_unknown_attr.as_ref().map(\|a\| &a.directive)
	{

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rust-timer commented Apr 18, 2026

Overall result: no relevant changes - no action needed

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