Unify `CoroutineWitness` sooner in typeck, and stall coroutine obligations based off of `TypingEnv` #141762

compiler-errors · 2025-05-30T11:21:33Z

Stall coroutine obligations based off of TypingMode in the old solver.
Eagerly assign TyKind::CoroutineWitness to the witness arg of coroutines during typeck, rather than deferring them to the end of typeck.

r? lcnr

This is part of #143017.

compiler-errors · 2025-05-30T11:21:40Z

@bors try @rust-timer queue

[experimental] Make witnesses more eager r? lcnr

bors · 2025-05-30T11:22:51Z

⌛ Trying commit 7bff9fb with merge aa7f5f1...

lcnr · 2025-05-30T11:26:50Z

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -1508,7 +1508,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                defining_opaque_types_and_generators: defining_opaque_types,
            }
            | TypingMode::Borrowck { defining_opaque_types } => {
-                defining_opaque_types.is_empty() || !pred.has_opaque_types()
+                defining_opaque_types.is_empty()
+                    || (!pred.has_opaque_types() && !pred.has_coroutines())


i feel like we prolly want to instead never erase the coroutines, only the defining opaques when creating a TypingEnv from the current infcx

might be expensive to erase on every call to TypingEnv; otherwise i'll keep this and write a comment explaining why it's unsound.

hmm, we don't need to check for has_coroutines with TypingMode::Borrowck. But yeah, please add a comment here

bors · 2025-05-30T13:46:43Z

☀️ Try build successful - checks-actions
Build commit: aa7f5f1 (aa7f5f1743a191388f6b130b1ea65bcfa321c198)

rust-timer · 2025-05-31T01:08:00Z

Finished benchmarking commit (aa7f5f1): comparison URL.

Overall result: ✅ improvements - no action needed

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

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

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.2%	[-0.2%, -0.2%]	2
Improvements ✅ (secondary)	-0.4%	[-0.6%, -0.2%]	5
All ❌✅ (primary)	-0.2%	[-0.2%, -0.2%]	2

Max RSS (memory usage)

Results (primary -0.4%, secondary -1.3%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	1.6%	[1.6%, 1.6%]	1
Regressions ❌ (secondary)	0.5%	[0.4%, 0.5%]	3
Improvements ✅ (primary)	-1.4%	[-1.6%, -1.3%]	2
Improvements ✅ (secondary)	-1.6%	[-3.9%, -0.6%]	17
All ❌✅ (primary)	-0.4%	[-1.6%, 1.6%]	3

Cycles

Results (secondary -0.1%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	1.0%	[0.4%, 2.4%]	9
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.4%	[-3.7%, -0.5%]	8
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: missing data
Artifact size: 370.26 MiB -> 370.23 MiB (-0.01%)

compiler-errors · 2025-06-09T17:00:24Z

@bors2 try @rust-timer queue

rust-bors · 2025-06-09T17:00:27Z

⌛ Trying commit 5862717 with merge 9676755…

To cancel the try build, run the command @bors2 try cancel.

[experimental] Make witnesses more eager r? lcnr

rust-bors · 2025-06-09T17:19:16Z

💔 Test failed

CI ❌

compiler-errors · 2025-06-09T20:53:19Z

@bors2 try @rust-timer queue

rust-bors · 2025-06-09T20:53:23Z

⌛ Trying commit ec8dc45 with merge c5243c3…

To cancel the try build, run the command @bors2 try cancel.

[experimental] Make witnesses more eager r? lcnr

rust-bors · 2025-06-09T23:23:28Z

☀️ Try build successful (CI)
Build commit: c5243c3 (c5243c3809f813c22efa750866301fd67942ef25)

rust-timer · 2025-06-10T01:54:23Z

Finished benchmarking commit (c5243c3): 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)	0.5%	[0.4%, 0.6%]	8
Regressions ❌ (secondary)	0.8%	[0.1%, 1.8%]	20
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.8%	[-0.9%, -0.6%]	3
All ❌✅ (primary)	0.5%	[0.4%, 0.6%]	8

Max RSS (memory usage)

Results (secondary 1.3%)

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)	1.9%	[1.2%, 3.5%]	5
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.2%	[-2.2%, -2.2%]	1
All ❌✅ (primary)	-	-	0

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: 754.885s -> 753.548s (-0.18%)
Artifact size: 372.30 MiB -> 372.33 MiB (0.01%)

compiler-errors · 2025-06-25T15:45:18Z

Crater regressions are spurious. I think this is ready to review more. I'll open a tracking issue for "removing CoroutineWitness" because I think this is just the first step in that process.

compiler/rustc_trait_selection/src/traits/select/mod.rs

compiler/rustc_type_ir/src/flags.rs

tests/ui/coroutine/clone-impl.rs

lcnr · 2025-06-27T07:42:16Z

r=me with the nits btw

bors · 2025-06-27T07:52:26Z

☔ The latest upstream changes (presumably #142223) made this pull request unmergeable. Please resolve the merge conflicts.

lcnr · 2025-07-03T13:50:21Z

@rustbot author

compiler-errors · 2025-07-17T19:57:44Z

@bors r=lcnr rollup=never

bors · 2025-07-17T19:57:47Z

📌 Commit 216cdb7 has been approved by lcnr

It is now in the queue for this repository.

bors · 2025-07-17T20:02:25Z

⌛ Testing commit 216cdb7 with merge e466296...

bors · 2025-07-17T23:04:49Z

☀️ Test successful - checks-actions
Approved by: lcnr
Pushing e466296 to master...

github-actions · 2025-07-17T23:08:11Z

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 9cd918b (parent) -> e466296 (this PR)

Test differences

Show 9 test diffs

9 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 e4662966273ed58b51f9ff8d682accc202aa1210 --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-apple-2: 4760.6s -> 5377.3s (13.0%)
x86_64-apple-1: 7719.1s -> 6846.0s (-11.3%)
dist-apple-various: 7243.9s -> 6554.6s (-9.5%)
tidy: 70.6s -> 63.9s (-9.4%)
aarch64-apple: 4395.7s -> 3999.3s (-9.0%)
dist-x86_64-netbsd: 4993.3s -> 4606.0s (-7.8%)
dist-ohos-x86_64: 4484.3s -> 4157.8s (-7.3%)
pr-check-1: 1564.7s -> 1675.3s (7.1%)
dist-aarch64-apple: 6425.1s -> 5976.5s (-7.0%)
x86_64-gnu-tools: 3824.9s -> 3560.0s (-6.9%)

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 · 2025-07-18T00:14:38Z

Finished benchmarking commit (e466296): 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)	0.3%	[0.2%, 0.3%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.5%	[-0.6%, -0.3%]	4
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 2.7%, secondary -3.5%)

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

	mean	range	count
Regressions ❌ (primary)	2.7%	[2.7%, 2.7%]	1
Regressions ❌ (secondary)	3.0%	[3.0%, 3.0%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-5.1%	[-6.2%, -4.2%]	4
All ❌✅ (primary)	2.7%	[2.7%, 2.7%]	1

Cycles

Results (primary 2.9%)

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

	mean	range	count
Regressions ❌ (primary)	8.3%	[8.3%, 8.3%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.5%	[-2.5%, -2.5%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.9%	[-2.5%, 8.3%]	2

Binary size

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

Bootstrap: 464.098s -> 464.163s (0.01%)
Artifact size: 374.74 MiB -> 374.68 MiB (-0.01%)

Unify `CoroutineWitness` sooner in typeck, and stall coroutine obligations based off of `TypingEnv` * Stall coroutine obligations based off of `TypingMode` in the old solver. * Eagerly assign `TyKind::CoroutineWitness` to the witness arg of coroutines during typeck, rather than deferring them to the end of typeck. r? lcnr This is part of rust-lang#143017.

rustbot assigned lcnr May 30, 2025

rustbot added 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 May 30, 2025