only next-solver: move implied bounds computation out of borrowck by lcnr · Pull Request #161047 · rust-lang/rust

lcnr · 2026-08-13T11:47:39Z

version of #160491 which does not enable this change for the old solver, meaning that we can merge it without a types team FCP :>

r? adwinwhite

rustbot · 2026-08-13T11:47:44Z

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

adwinwhite · 2026-08-14T01:19:13Z

@bors try @rust-timer queue

only next-solver: move implied bounds computation out of borrowck

rust-bors · 2026-08-14T02:18:18Z

☀️ Try build successful (CI)
Build commit: 64561ff (64561ffbe3ce67ee25e5f81cbfc58680b0b69753)
Base parent: 93c9086 (93c9086fdd5b80d286480a19ac047746ecc5fa1f)

rust-timer · 2026-08-14T03:01:19Z

Finished benchmarking commit (64561ff): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

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.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@bors rollup=never rustc-perf
@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)	1.1%	[0.7%, 1.6%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.5%	[-0.6%, -0.2%]	7
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 0.4%, secondary -0.7%)

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

	mean	range	count
Regressions ❌ (primary)	1.9%	[1.9%, 1.9%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.0%	[-1.0%, -1.0%]	1
Improvements ✅ (secondary)	-0.7%	[-0.7%, -0.7%]	1
All ❌✅ (primary)	0.4%	[-1.0%, 1.9%]	2

Cycles

Results (primary -0.5%, 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)	2.4%	[2.4%, 2.4%]	1
Regressions ❌ (secondary)	5.7%	[2.3%, 9.3%]	5
Improvements ✅ (primary)	-3.3%	[-3.3%, -3.3%]	1
Improvements ✅ (secondary)	-3.4%	[-4.0%, -2.5%]	3
All ❌✅ (primary)	-0.5%	[-3.3%, 2.4%]	2

Binary size

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

Bootstrap: 455.615s -> 458.36s (0.60%)
Artifact size: 396.47 MiB -> 398.86 MiB (0.60%)

adwinwhite · 2026-08-14T03:18:24Z

This fixes a soundness hole in borrowck. Since this only affects a single crate in benchmark, we can look into it later alongside our current next‑solver perf work.
@rustbot label: +perf-regression-triaged

@bors r+

rust-bors · 2026-08-14T03:18:27Z

📌 Commit e77a2d7 has been approved by adwinwhite

It is now in the queue for this repository.

to enable the new solver for testing without needing to FCP the changes to the old one.

rustbot · 2026-08-14T15:58:36Z

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.

lcnr · 2026-08-14T19:44:50Z

@bors r=adwinwhite

rust-bors · 2026-08-14T19:44:53Z

📌 Commit 457c9db has been approved by adwinwhite

It is now in the queue for this repository.

jhpratt · 2026-08-15T01:55:03Z

@bors p=6 scheduling

rust-bors · 2026-08-15T05:24:40Z

☀️ Test successful - CI
Approved by: adwinwhite
Duration: 3h 15m 52s
Pushing 0844f35 to main...

github-actions · 2026-08-15T05:28:06Z

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 68c677a (parent) -> 0844f35 (this PR)

Test differences

Show 59 test diffs

Stage 1

[ui (polonius)] tests/ui/impl-trait/wf-check-hidden-type.rs: pass -> [missing] (J0)
[ui (polonius)] tests/ui/impl-trait/wf-check-hidden-type.rs#current: [missing] -> pass (J0)
[ui (polonius)] tests/ui/impl-trait/wf-check-hidden-type.rs#next: [missing] -> pass (J0)
[ui (polonius)] tests/ui/traits/next-solver/opaques/implied-bounds-cyclic-reasoning.rs#current: [missing] -> pass (J0)
[ui (polonius)] tests/ui/traits/next-solver/opaques/implied-bounds-cyclic-reasoning.rs#next: [missing] -> pass (J0)
[ui (polonius)] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-2.rs#current: [missing] -> pass (J0)
[ui (polonius)] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-2.rs#next: [missing] -> pass (J0)
[ui (polonius)] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-3.rs#current: [missing] -> pass (J0)
[ui (polonius)] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-3.rs#next: [missing] -> pass (J0)
[ui (polonius)] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-pass.rs#current: [missing] -> pass (J0)
[ui (polonius)] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-pass.rs#next: [missing] -> pass (J0)
[ui (polonius)] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-rpitit.rs#current: [missing] -> pass (J0)
[ui (polonius)] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-rpitit.rs#next: [missing] -> pass (J0)
[ui (polonius)] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty.rs#current: [missing] -> pass (J0)
[ui (polonius)] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty.rs#next: [missing] -> pass (J0)
[ui (polonius)] tests/ui/traits/next-solver/opaques/implied-bounds-opaque-hidden-in-closure-sig.rs#current: [missing] -> pass (J0)
[ui (polonius)] tests/ui/traits/next-solver/opaques/implied-bounds-opaque-hidden-in-closure-sig.rs#next: [missing] -> pass (J0)
[ui] tests/ui/impl-trait/wf-check-hidden-type.rs: pass -> [missing] (J1)
[ui] tests/ui/impl-trait/wf-check-hidden-type.rs#current: [missing] -> pass (J1)
[ui] tests/ui/impl-trait/wf-check-hidden-type.rs#next: [missing] -> pass (J1)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-cyclic-reasoning.rs#current: [missing] -> pass (J1)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-cyclic-reasoning.rs#next: [missing] -> pass (J1)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-2.rs#current: [missing] -> pass (J1)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-2.rs#next: [missing] -> pass (J1)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-3.rs#current: [missing] -> pass (J1)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-3.rs#next: [missing] -> pass (J1)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-pass.rs#current: [missing] -> pass (J1)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-pass.rs#next: [missing] -> pass (J1)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-rpitit.rs#current: [missing] -> pass (J1)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-rpitit.rs#next: [missing] -> pass (J1)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty.rs#current: [missing] -> pass (J1)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty.rs#next: [missing] -> pass (J1)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-opaque-hidden-in-closure-sig.rs#current: [missing] -> pass (J1)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-opaque-hidden-in-closure-sig.rs#next: [missing] -> pass (J1)

Stage 2

[ui] tests/ui/impl-trait/wf-check-hidden-type.rs: pass -> [missing] (J2)
[ui] tests/ui/impl-trait/wf-check-hidden-type.rs#current: [missing] -> pass (J2)
[ui] tests/ui/impl-trait/wf-check-hidden-type.rs#next: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-cyclic-reasoning.rs#current: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-cyclic-reasoning.rs#next: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-2.rs#current: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-2.rs#next: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-3.rs#current: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-3.rs#next: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-pass.rs#current: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-pass.rs#next: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-rpitit.rs#current: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty-rpitit.rs#next: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty.rs#current: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-leak-hidden-ty.rs#next: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-opaque-hidden-in-closure-sig.rs#current: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/opaques/implied-bounds-opaque-hidden-in-closure-sig.rs#next: [missing] -> pass (J2)

Additionally, 8 doctest diffs were found. These are ignored, as they are noisy.

Job group index

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 0844f35a32c98882d77e39da8c2a872ec74615cd --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

x86_64-gnu-stdlib-semver-check: 4m 26s -> 12m 39s (+184.7%)
x86_64-rust-for-linux: 28m 43s -> 53m 20s (+85.7%)
x86_64-gnu-gcc-core-tests: 8m 7s -> 14m 9s (+74.1%)
i686-gnu-nopt-2: 1h 26m -> 2h 22m (+64.9%)
x86_64-gnu-miri: 55m 25s -> 1h 24m (+52.4%)
dist-aarch64-linux: 1h 51m -> 2h 40m (+43.7%)
i686-gnu-2: 1h 11m -> 1h 41m (+42.2%)
x86_64-gnu-llvm-22-1: 55m 54s -> 1h 17m (+39.0%)
x86_64-gnu-llvm-21-3: 1h 24m -> 1h 48m (+28.8%)
dist-powerpc64le-linux-gnu: 1h 15m -> 1h 36m (+27.9%)

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 · 2026-08-15T06:07:54Z

Finished benchmarking commit (0844f35): comparison URL.

Overall result: ❌✅ regressions and improvements - 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)	0.4%	[0.4%, 0.4%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.5%	[-0.6%, -0.4%]	3
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

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

Cycles

Results (primary 2.1%, 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)	2.1%	[2.0%, 2.1%]	3
Regressions ❌ (secondary)	5.4%	[1.0%, 9.3%]	5
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.1%	[-4.9%, -1.9%]	9
All ❌✅ (primary)	2.1%	[2.0%, 2.1%]	3

Binary size

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

Bootstrap: 459.748s -> 465.176s (1.18%)
Artifact size: 396.48 MiB -> 399.05 MiB (0.65%)

rustbot assigned adwinwhite Aug 13, 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. WG-trait-system-refactor The Rustc Trait System Refactor Initiative (-Znext-solver) labels Aug 13, 2026

lcnr mentioned this pull request Aug 13, 2026

move implied bounds computation out of borrowck #160491

Open

lcnr changed the title ~~Implied bounds opaque only next~~ only next-solver: move implied bounds computation out of borrowck Aug 13, 2026

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rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Aug 14, 2026

rust-bors Bot pushed a commit that referenced this pull request Aug 14, 2026

Auto merge of #161047 - lcnr:implied-bounds-opaque-only-next, r=<try>

64561ff

only next-solver: move implied bounds computation out of borrowck

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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 Aug 14, 2026

rustbot added the perf-regression-triaged The performance regression has been triaged. label Aug 14, 2026

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lcnr added 5 commits August 14, 2026 17:54

move implied bounds computation out of borrowck

a6309f7

fix implied bound computation for nested bodies

c34440a

move compute implied bounds into sub-fn

6de1547

review and stuff

d1fc585

only change implied bounds behavior with next-solver

457c9db

to enable the new solver for testing without needing to FCP the changes to the old one.

lcnr force-pushed the implied-bounds-opaque-only-next branch from e77a2d7 to 457c9db Compare August 14, 2026 15:58

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 Aug 14, 2026

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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 Aug 15, 2026

rust-bors Bot merged commit 0844f35 into rust-lang:main Aug 15, 2026
14 checks passed

rustbot added this to the 1.99.0 milestone Aug 15, 2026

This was referenced Aug 15, 2026

Fix coroutine witness trait solving with NLL-derived facts #160940

Draft

Clean up and speed up inference variable resolving code #160913

Open

rustbot removed the perf-regression Performance regression. label Aug 15, 2026

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rust-timer commented Aug 14, 2026

Overall result: ❌✅ regressions and improvements - please read:

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Test differences

Stage 1

Stage 2

Job duration changes

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rust-timer commented Aug 15, 2026

Overall result: ❌✅ regressions and improvements - no action needed

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lcnr commented Aug 13, 2026 •

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