Abstract AST lowering resolver by aerooneqq · Pull Request #153656 · rust-lang/rust

aerooneqq · 2026-03-10T13:06:14Z

This PR adds new methods for ResolverAstLoweringExt for future use in #153489 and abstracts resolver in lowering through generic parameters.

~~This PR splits resolver for AST lowering into two parts: mutable and readonly. This will allow us to use borrowed resolver in #153489, when we will not steal but borrow resolver from resolve stage.~~

Second step for #153489.

r? @petrochenkov

petrochenkov · 2026-03-10T13:14:33Z

@bors try @rust-timer queue

Split AST lowering resolver into mutable and readonly parts

rust-bors · 2026-03-10T15:31:17Z

☀️ Try build successful (CI)
Build commit: 34c6408 (34c640855259775e106a9bb690dca6e253708e88, parent: 3bc6ea5673e3e292db1e5b6ecaaaa883ca5af0b8)

rust-timer · 2026-03-10T16:42:50Z

Finished benchmarking commit (34c6408): 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)	0.3%	[0.1%, 0.5%]	88
Regressions ❌ (secondary)	0.2%	[0.0%, 0.4%]	24
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.3%	[0.1%, 0.5%]	88

Max RSS (memory usage)

Results (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)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.3%	[-2.3%, -2.3%]	1
All ❌✅ (primary)	-	-	0

Cycles

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

Binary size

Results (primary -0.0%, secondary -0.1%)

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)	-	-	0
Improvements ✅ (primary)	-0.0%	[-0.0%, -0.0%]	15
Improvements ✅ (secondary)	-0.1%	[-0.1%, -0.0%]	5
All ❌✅ (primary)	-0.0%	[-0.0%, -0.0%]	15

Bootstrap: 479.559s -> 479.738s (0.04%)
Artifact size: 394.94 MiB -> 394.96 MiB (0.00%)

petrochenkov · 2026-03-11T07:34:52Z

@bors try @rust-timer queue

Split AST lowering resolver into mutable and readonly parts

rust-bors · 2026-03-11T09:43:59Z

☀️ Try build successful (CI)
Build commit: fd90094 (fd900941fd5f18ffa2e76d2485bc973cbe4785b5, parent: d1c79458b5d13bd0179d7dbafd5ca4ea9ae3e6aa)

rust-timer · 2026-03-11T10:24:20Z

Finished benchmarking commit (fd90094): 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)	0.3%	[0.1%, 0.5%]	73
Regressions ❌ (secondary)	0.2%	[0.1%, 0.3%]	20
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.3%	[0.1%, 0.5%]	73

Max RSS (memory usage)

Results (secondary -3.3%)

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)	0.9%	[0.9%, 0.9%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-7.4%	[-7.4%, -7.4%]	1
All ❌✅ (primary)	-	-	0

Cycles

Results (primary -1.8%, secondary 0.1%)

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)	2.1%	[2.1%, 2.1%]	1
Improvements ✅ (primary)	-1.8%	[-1.8%, -1.8%]	1
Improvements ✅ (secondary)	-2.0%	[-2.0%, -2.0%]	1
All ❌✅ (primary)	-1.8%	[-1.8%, -1.8%]	1

Binary size

Results (primary 0.0%, secondary 0.1%)

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

	mean	range	count
Regressions ❌ (primary)	0.0%	[0.0%, 0.1%]	26
Regressions ❌ (secondary)	0.1%	[0.0%, 0.1%]	19
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.0%	[0.0%, 0.1%]	26

Bootstrap: 479.3s -> 481.187s (0.39%)
Artifact size: 396.94 MiB -> 394.92 MiB (-0.51%)

petrochenkov · 2026-03-12T14:39:54Z

@bors try @rust-timer queue

Split AST lowering resolver into mutable and readonly parts

rust-bors · 2026-03-12T16:49:48Z

☀️ Try build successful (CI)
Build commit: 3cf00c2 (3cf00c237b8526db29ae46b6f794e2b7b20cbe09, parent: d1ee5e59a964a419b84b760812a35075034f4861)

petrochenkov · 2026-03-18T13:12:38Z

The PR description needs some update, the lowering resolver was already abstracted through ResolverAstLoweringExt, this PR just adds more methods to that abstraction (because the future PR #XXXXX needs them for this and that).

aerooneqq · 2026-03-18T14:05:40Z

@rustbot ready

petrochenkov · 2026-03-18T14:29:46Z

r=me after squashing commits.
@rustbot author

rustbot · 2026-03-18T14:29:52Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

aerooneqq · 2026-03-18T14:32:06Z

@rustbot ready

petrochenkov · 2026-03-18T14:34:40Z

@bors r+

rust-bors · 2026-03-18T14:34:44Z

📌 Commit 3656fbf has been approved by petrochenkov

It is now in the queue for this repository.

rust-bors · 2026-03-18T18:12:41Z

☀️ Test successful - CI
Approved by: petrochenkov
Duration: 3h 11m 21s
Pushing fd0c901 to main...

github-actions · 2026-03-18T18:15:46Z

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 53d60bb (parent) -> fd0c901 (this PR)

Test differences

Show 3 test diffs

3 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 fd0c901b00ee1e08a250039cdb90258603497e20 --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

aarch64-apple: 3h 43m -> 2h 50m (-23.8%)
i686-gnu-nopt-1: 2h 24m -> 2h 1m (-15.9%)
test-various: 2h 10m -> 1h 51m (-14.7%)
dist-apple-various: 1h 34m -> 1h 46m (+12.8%)
x86_64-gnu: 2h 22m -> 2h 5m (-12.2%)
i686-gnu-1: 2h 10m -> 1h 56m (-11.4%)
pr-check-1: 31m 38s -> 28m 5s (-11.2%)
x86_64-gnu-tools: 1h 3m -> 56m 10s (-11.0%)
dist-aarch64-apple: 1h 51m -> 2h 1m (+9.2%)
aarch64-gnu-debug: 1h 16m -> 1h 9m (-8.9%)

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 · 2026-03-18T18:53:15Z

Finished benchmarking commit (fd0c901): 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)	0.2%	[0.1%, 0.3%]	6
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

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

Binary size

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

Bootstrap: 479.87s -> 481.003s (0.24%)
Artifact size: 397.03 MiB -> 396.91 MiB (-0.03%)

@petrochenkov

…r, r=petrochenkov Abstract AST lowering resolver This PR adds new methods for `ResolverAstLoweringExt` for future use in rust-lang#153489 and abstracts resolver in lowering through generic parameters. > ~This PR splits resolver for AST lowering into two parts: mutable and readonly. This will allow us to use borrowed resolver in rust-lang#153489, when we will not steal but borrow resolver from resolve stage.~ Second step for rust-lang#153489. r? @petrochenkov

@petrochenkov

Do not modify resolver outputs during lowering Split from #142830 I believe this achieves the same thing as #153656 but in a much simpler way. This PR forces AST->HIR lowering to stop mutating resolver outputs. Instead, it manages a few override maps that only live during lowering and are dropped afterwards. r? @petrochenkov cc @aerooneqq

rustbot assigned petrochenkov Mar 10, 2026

rustbot added 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 Mar 10, 2026

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rust-borsBot pushed a commit that referenced this pull request Mar 10, 2026
Auto merge of#153656- aerooneqq:split-ast-lowering-resolver, r=<try>
34c6408
Split AST lowering resolver into mutable and readonly parts

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Mar 10, 2026

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rustbot added perf-regression Performance regression. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Mar 10, 2026

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rust-borsBot pushed a commit that referenced this pull request Mar 11, 2026
Auto merge of#153656- aerooneqq:split-ast-lowering-resolver, r=<try>
fd90094
Split AST lowering resolver into mutable and readonly parts

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Mar 11, 2026

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Mar 11, 2026

aerooneqq force-pushed the split-ast-lowering-resolver branch from 6ddfe68 to 8158d7fCompare March 12, 2026 13:50

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rust-borsBot pushed a commit that referenced this pull request Mar 12, 2026
Auto merge of#153656- aerooneqq:split-ast-lowering-resolver, r=<try>
3cf00c2
Split AST lowering resolver into mutable and readonly parts

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Mar 12, 2026

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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 Mar 18, 2026

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 Mar 18, 2026

Abstract AST lowering resolver
3656fbf

aerooneqq force-pushed the split-ast-lowering-resolver branch from 69f6ab2 to 3656fbfCompare March 18, 2026 14:31

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 Mar 18, 2026

rust-borsBot 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 Mar 18, 2026

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rust-borsBot 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 Mar 18, 2026

rust-borsBot merged commit fd0c901 into rust-lang:mainMar 18, 2026
12 checks passed

rustbot added this to the 1.96.0 milestone Mar 18, 2026

rust-borsBot mentioned this pull request Mar 18, 2026
delegation: fix def path hash collision, add per parent disambiguators #153955
Merged

aerooneqq deleted the split-ast-lowering-resolver branch March 18, 2026 19:43

cjgillot mentioned this pull request Apr 17, 2026
Do not modify resolver outputs during lowering #155460
Merged

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rust-timer commented Mar 10, 2026

Overall result: ❌ regressions - please read the text below

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Overall result: ❌ regressions - please read the text below

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Test differences

Job duration changes

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Overall result: ❌ regressions - no action needed

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aerooneqq commented Mar 10, 2026•
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