Migration of LintDiagnostic - part 5 by GuillaumeGomez · Pull Request #153152 · rust-lang/rust

GuillaumeGomez · 2026-02-26T20:40:42Z

With this, rust_lint is finally done, although the change of API of decorate_builtin_lint impacted a few other crates, although minimal, still needed to be mentioned.

r? @JonathanBrouwer

…agnostic`

rustbot · 2026-02-26T20:40:47Z

JonathanBrouwer is currently at their maximum review capacity.
They may take a while to respond.

JonathanBrouwer · 2026-02-26T21:38:36Z

@bors try @rust-timer queue

Migration of LintDiagnostic - part 5

JonathanBrouwer · 2026-02-26T21:44:29Z

compiler/rustc_lint/src/early/diagnostics.rs

    tcx: Option<TyCtxt<'_>>,
    diagnostic: BuiltinLintDiag,
-    diag: &mut Diag<'_, ()>,
+    lint: &'static Lint,


Does this function need to know about lint? Could lint just be inside the ctx instead?

Sounds good to me!

JonathanBrouwer · 2026-02-26T21:47:21Z

src/librustdoc/lib.rs

    Ok(())
 }

+struct DiagEmitter<'tcx> {


Would it be possible to reuse the DiagEmitter struct from rustc_hir_analysis here instead?
If that's annoying dependency-wise, can we put the diag-emitter struct in a logical shared location that both can access? Bonus points if we manage to move the entire "emit delayed lints" for loop below into a shared lcoation
If not to both then this is ok, just a bit of sad duplication

No, duplication bad. Me removing duplication. 🔨

(Yeah ok I should maybe go sleep...)

JonathanBrouwer · 2026-02-26T21:50:02Z

compiler/rustc_lint/src/context.rs

-            decorator.decorate_lint(lint);
-        });
-    }
-


Would it be hard to keep this function but make it emit a diagnostic instead?
I think I prefer having it generic over having a specific NonUpperCaseGlobalGenerator struct

Noting it for a next PR then. :)

JonathanBrouwer · 2026-02-26T21:52:04Z

compiler/rustc_lint/src/early/diagnostics.rs

    tcx: Option<TyCtxt<'_>>,
    diagnostic: BuiltinLintDiag,
-    diag: &mut Diag<'_, ()>,
+    lint: &'static Lint,


I've added to the TODO list in the tracking issue: See if we can get rid of BuiltinLintDiag in favour of a boxed diagnostic of some kind

That would be very nice indeed.

GuillaumeGomez · 2026-02-26T23:18:42Z

Simplified EmitDiag and removed duplicated code. Keeping the last item for after this PR is merged as it's already big enough.

rust-bors · 2026-02-26T23:50:31Z

☀️ Try build successful (CI)
Build commit: 0c55ed2 (0c55ed2450ed4df93bd1cbfbca3f3e31a391a171, parent: 25396cf54981afd1fa5a7406658b45033106a0d3)

rust-timer · 2026-02-27T03:22:37Z

Finished benchmarking commit (0c55ed2): comparison URL.

Overall result: ❌ regressions - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

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

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.3%	[0.5%, 3.8%]	13
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

This benchmark run did not return any relevant results for this metric.

Cycles

Results (primary -6.1%, secondary 2.3%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	4.0%	[3.7%, 4.7%]	3
Improvements ✅ (primary)	-6.1%	[-6.1%, -6.1%]	1
Improvements ✅ (secondary)	-3.0%	[-3.0%, -3.0%]	1
All ❌✅ (primary)	-6.1%	[-6.1%, -6.1%]	1

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 481.72s -> 480.975s (-0.15%)
Artifact size: 395.60 MiB -> 395.80 MiB (0.05%)

JonathanBrouwer · 2026-02-27T09:24:36Z

If not too annoying I'd like to see the perf regression fixed as well

… and `rustdoc`

GuillaumeGomez added 4 commits February 26, 2026 17:46

Remove unused LintContext::emit_lint method

f64bdad

Remove LintContext::emit_span_lint_lazy

5be09c8

Migrate most rustc_lint lint to Diagnostic

36ad6ff

Update decorate_builtin_lint to use Diagnostic instead of `LintDi…

b352490

…agnostic`

rustbot assigned JonathanBrouwer Feb 26, 2026

rustbot added 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. T-rustdoc Relevant to the rustdoc team, which will review and decide on the PR/issue. labels Feb 26, 2026

This comment has been minimized.

Sign in to view

rust-bors bot pushed a commit that referenced this pull request Feb 26, 2026

Auto merge of #153152 - GuillaumeGomez:migrate-diag, r=<try>

0c55ed2

Migration of LintDiagnostic - part 5

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Feb 26, 2026

JonathanBrouwer requested changes Feb 26, 2026

View reviewed changes

rustbot 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 Feb 26, 2026

JonathanBrouwer reviewed Feb 26, 2026

View reviewed changes

Simplify rustc_lint::EmitDiag by removing Lint from its API

2b502f5

This comment has been minimized.

Sign in to view

rustbot added perf-regression Performance regression. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Feb 27, 2026

Remove duplicated code for delayed lints between rustc_hir_analysis…

f3d639f

… and `rustdoc`

GuillaumeGomez force-pushed the migrate-diag branch from d39a00a to f3d639f Compare February 27, 2026 17:23

GuillaumeGomez mentioned this pull request Feb 27, 2026

Perf check for Diag migration #153193

Draft

Uh oh!

Conversation

GuillaumeGomez commented Feb 26, 2026

Uh oh!

rustbot commented Feb 26, 2026

Uh oh!

JonathanBrouwer commented Feb 26, 2026

Uh oh!

This comment has been minimized.

This comment has been minimized.

JonathanBrouwer Feb 26, 2026 • 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!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

GuillaumeGomez commented Feb 26, 2026

Uh oh!

This comment has been minimized.

rust-bors bot commented Feb 26, 2026

Uh oh!

This comment has been minimized.

rust-timer commented Feb 27, 2026

Overall result: ❌ regressions - please read the text below

Uh oh!

JonathanBrouwer commented Feb 27, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

5 participants

JonathanBrouwer Feb 26, 2026 •

edited

Loading