Use fine grained component-wise span tracking in use trees by oli-obk · Pull Request #153838 · rust-lang/rust

oli-obk · 2026-03-13T21:00:54Z

This often produces nicer spans and even doesn't need a Span field anymore (not that I expect the unused field to affect any perf, but still neat).

rustbot · 2026-03-13T21:00:58Z

The parser was modified, potentially altering the grammar of (stable) Rust
which would be a breaking change.

cc @fmease

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

rustbot · 2026-03-13T21:01:00Z

r? @davidtwco

rustbot has assigned @davidtwco.
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

Why was this reviewer chosen?

The reviewer was selected based on:

Owners of files modified in this PR: compiler
compiler expanded to 69 candidates
Random selection from 15 candidates

oli-obk · 2026-03-13T21:02:24Z

   |
 LL -         with_crate!{$crate input TokenItem}
-LL +         with_crate!{token_site_span::TokenItem as _ input TokenItem}
+LL +         with_crate!{token_site_span::TokenItem as _}


These suggestions are now even more broken than before, but considering it was broken before, I think we should just leave it

rustbot · 2026-03-17T20:10:50Z

Some changes occurred in src/tools/rustfmt

cc @rust-lang/rustfmt

oli-obk · 2026-03-17T20:11:19Z

@bors try @rust-timer queue

Use fine grained component-wise span tracking in use trees

rust-bors · 2026-03-17T22:20:14Z

☀️ Try build successful (CI)
Build commit: cefe872 (cefe8725ef5e7dbcaead19ae9024d25a96ac5731, parent: b711f95f86b6489b91fdc55c876ed5f95a8d4560)

rust-timer · 2026-03-17T23:00:30Z

Finished benchmarking commit (cefe872): comparison URL.

Overall result: ❌ regressions - no action needed

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.

@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)	0.5%	[0.1%, 0.9%]	6
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 0.4%, secondary -0.2%)

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

	mean	range	count
Regressions ❌ (primary)	0.4%	[0.4%, 0.4%]	2
Regressions ❌ (secondary)	1.4%	[1.1%, 1.6%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.3%	[-1.5%, -1.0%]	3
All ❌✅ (primary)	0.4%	[0.4%, 0.4%]	2

Cycles

Results (secondary 11.5%)

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)	11.5%	[11.5%, 11.5%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 481.409s -> 480.983s (-0.09%)
Artifact size: 394.91 MiB -> 394.79 MiB (-0.03%)

cjgillot · 2026-03-18T00:45:16Z

+        self.prefix.span.to(self.hi_span())
+    }
+
+    pub fn hi_span(&self) -> Span {


Could you document what are the results of span() and hi_span(), and how they can be different?

davidtwco

r=me after resolving @cjgillot's comments

View changes since this review

rustbot · 2026-04-08T10:38:46Z

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.

oli-obk · 2026-04-08T10:38:53Z

@bors r=davidtwco

rust-bors · 2026-04-08T10:38:57Z

📌 Commit 033ccb0 has been approved by davidtwco

It is now in the queue for this repository.

rust-bors · 2026-04-08T23:19:30Z

☀️ Test successful - CI
Approved by: davidtwco
Duration: 3h 9m 53s
Pushing 9004856 to main...

github-actions · 2026-04-08T23:22:37Z

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing 033b925 (parent) -> 9004856 (this PR)

Test differences

Show 7 test diffs

7 doctest diffs were found. These are ignored, as they are noisy.

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 900485642855f4729d926ecf24680a791f9293cf --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

test-various: 1h 43m -> 2h 9m (+25.4%)
pr-check-1: 27m 10s -> 33m 52s (+24.7%)
aarch64-gnu-llvm-21-1: 51m 21s -> 1h 2m (+21.9%)
dist-arm-linux-gnueabi: 1h 27m -> 1h 9m (-21.5%)
x86_64-gnu-llvm-21: 1h 15m -> 1h 30m (+20.3%)
x86_64-gnu-tools: 56m 19s -> 1h 6m (+18.5%)
x86_64-rust-for-linux: 46m 21s -> 53m 40s (+15.8%)
dist-various-1: 1h 5m -> 1h 13m (+13.3%)
i686-gnu-2: 1h 28m -> 1h 40m (+12.9%)
dist-apple-various: 1h 49m -> 1h 35m (-12.8%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

rust-timer · 2026-04-09T00:01:17Z

Finished benchmarking commit (9004856): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -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)	0.7%	[0.1%, 1.0%]	4
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 1.8%)

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

	mean	range	count
Regressions ❌ (primary)	1.8%	[1.8%, 1.8%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.8%	[1.8%, 1.8%]	1

Cycles

Results (primary -1.7%, secondary 2.4%)

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)	2.4%	[2.4%, 2.4%]	1
Improvements ✅ (primary)	-1.7%	[-1.7%, -1.7%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.7%	[-1.7%, -1.7%]	1

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: 489.04s -> 489.506s (0.10%)
Artifact size: 395.48 MiB -> 395.50 MiB (0.00%)

oli-obk · 2026-04-09T12:36:41Z

The regressed benchmark has a lot of warnings that go through those code paths. It's somewhat expected that it's more expensive to generate a span for a lint, but these all only happen on the emission path

Use fine grained component-wise span tracking in use trees This often produces nicer spans and even doesn't need a Span field anymore (not that I expect the unused field to affect any perf, but still neat).

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-clippy Relevant to the Clippy team. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Mar 13, 2026

rustbot assigned davidtwco Mar 13, 2026

oli-obk commented Mar 13, 2026

View reviewed changes

This comment has been minimized.

Sign in to view

oli-obk force-pushed the use-tree-span branch from f676b85 to d276984 Compare March 16, 2026 11:09

This comment has been minimized.

Sign in to view

oli-obk force-pushed the use-tree-span branch from d276984 to 137ab4b Compare March 17, 2026 20:10

rustbot added the T-rustfmt Relevant to the rustfmt team, which will review and decide on the PR/issue. label Mar 17, 2026

This comment has been minimized.

Sign in to view

rust-bors Bot pushed a commit that referenced this pull request Mar 17, 2026

Auto merge of #153838 - oli-obk:use-tree-span, r=<try>

cefe872

Use fine grained component-wise span tracking in use trees

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Mar 17, 2026

This comment has been minimized.

Sign in to view

rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Mar 17, 2026

cjgillot reviewed Mar 18, 2026

View reviewed changes

davidtwco approved these changes Mar 26, 2026

View reviewed changes

oli-obk added 2 commits April 8, 2026 12:37

Use fine grained component-wise span tracking in use trees

9017621

Use the item span for DefKind::Use, it is never used anyway

033ccb0

oli-obk force-pushed the use-tree-span branch from 137ab4b to 033ccb0 Compare April 8, 2026 10:38

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 8, 2026

This comment has been minimized.

Sign in to view

rust-bors Bot added merged-by-bors This PR was explicitly merged by bors. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Apr 8, 2026

rust-bors Bot merged commit 9004856 into rust-lang:main Apr 8, 2026
12 checks passed

rustbot added this to the 1.96.0 milestone Apr 8, 2026

This was referenced Apr 8, 2026

Replacing self overwriting with proper resolution #152996

Merged

Merge BuildReducedGraphVisitor into DefPathVisitor #154945

Merged

oli-obk deleted the use-tree-span branch April 9, 2026 12:17

Uh oh!

Conversation

oli-obk commented Mar 13, 2026

Uh oh!

rustbot commented Mar 13, 2026

Uh oh!

rustbot commented Mar 13, 2026

Uh oh!

Choose a reason for hiding this comment

Uh oh!

This comment has been minimized.

This comment has been minimized.

rustbot commented Mar 17, 2026

Uh oh!

oli-obk commented Mar 17, 2026

Uh oh!

This comment has been minimized.

This comment has been minimized.

rust-bors Bot commented Mar 17, 2026

Uh oh!

This comment has been minimized.

rust-timer commented Mar 17, 2026

Overall result: ❌ regressions - no action needed

Uh oh!

Choose a reason for hiding this comment

Uh oh!

davidtwco 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!

rustbot commented Apr 8, 2026

Uh oh!

oli-obk commented Apr 8, 2026

Uh oh!

rust-bors Bot commented Apr 8, 2026

Uh oh!

This comment has been minimized.

rust-bors Bot commented Apr 8, 2026

Uh oh!

Uh oh!

github-actions Bot commented Apr 8, 2026

Test differences

Job duration changes

Uh oh!

rust-timer commented Apr 9, 2026

Overall result: ❌ regressions - no action needed

Uh oh!

oli-obk commented Apr 9, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

6 participants

davidtwco left a comment •

edited by rustbot

Loading