Use fulfillment in method probe, not evaluation #122317

compiler-errors · 2024-03-11T00:25:39Z

This PR reworks method probing to use fulfillment instead of a for-loop of evaluate_predicate calls, and moves normalization from method candidate assembly into the consider_probe, where it's applied to all candidates. This last part coincidentally fixes #121643 (comment).

Regarding why this large rewrite is done: In general, it's an anti-pattern to do for o in obligations { evaluate(o); } because it's not compatible with the way that the new solver emits alias-relate obligations which constrain variables that may show up in other predicates.

r? lcnr

rustbot · 2024-03-11T00:25:48Z

Some changes occurred in engine.rs, potentially modifying the public API of ObligationCtxt.

cc @lcnr, @compiler-errors

compiler/rustc_trait_selection/src/traits/engine.rs

compiler-errors · 2024-03-11T15:19:46Z

@bors try

compiler/rustc_hir_typeck/src/method/probe.rs

bors · 2024-03-11T15:20:56Z

⌛ Trying commit 3702ab1 with merge 1f75533...

…, r=<try> Use fulfillment in method probe, not evaluation This PR reworks method probing to use fulfillment instead of a `for`-loop of `evaluate_predicate` calls, and moves normalization from method candidate assembly into the `consider_probe`, where it's applied to *all* candidates. This last part coincidentally fixes rust-lang#121643 (comment). Regarding *why* this large rewrite is done: In general, it's an anti-pattern to do `for o in obligations { evaluate(o); }` because it's not compatible with the way that the new solver emits alias-relate obligations which constrain variables that may show up in other predicates. Putting this up for vibe-check mostly. Tests aren't yet blessed, and there are some nuances about whether it's worthwhile to restore regressed diagnostics. r? lcnr

bors · 2024-03-11T16:48:23Z

☀️ Try build successful - checks-actions
Build commit: 1f75533 (1f7553361c08f8eafdc645e09215667278ab86f4)

compiler-errors · 2024-03-11T16:57:50Z

@craterbot check

craterbot · 2024-03-11T16:57:57Z

👌 Experiment pr-122317 created and queued.
🤖 Automatically detected try build 1f75533
🔍 You can check out the queue and this experiment's details.

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

Crater rollup This is a crater rollup of: - [ ] rust-lang#122317 - [ ] rust-lang#122501 - [ ] rust-lang#122077 What does that mean? Well, I'm gonna run crater with p=3 on this PR, and then re-run *just* the list of failed crates on each PR. That should deduplicate the bulk of crates which we expect are unaffected by these PRs. Don't touch this PR please. r? `@ghost`

compiler-errors · 2024-03-14T23:11:08Z

@bors try

bors · 2024-03-14T23:12:18Z

⌛ Trying commit 35d6003 with merge 3aea706...

…, r=<try> Use fulfillment in method probe, not evaluation This PR reworks method probing to use fulfillment instead of a `for`-loop of `evaluate_predicate` calls, and moves normalization from method candidate assembly into the `consider_probe`, where it's applied to *all* candidates. This last part coincidentally fixes rust-lang#121643 (comment). Regarding *why* this large rewrite is done: In general, it's an anti-pattern to do `for o in obligations { evaluate(o); }` because it's not compatible with the way that the new solver emits alias-relate obligations which constrain variables that may show up in other predicates. Putting this up for vibe-check mostly. Tests aren't yet blessed, and there are some nuances about whether it's worthwhile to restore regressed diagnostics. r? lcnr

bors · 2024-03-15T00:41:13Z

☀️ Try build successful - checks-actions
Build commit: 3aea706 (3aea7069a654d82dd39c4479794b5560f4977307)

bors · 2024-03-15T00:41:13Z

☀️ Try build successful - checks-actions
Build commit: 3aea706 (3aea7069a654d82dd39c4479794b5560f4977307)

craterbot · 2024-03-18T15:10:39Z

🚧 Experiment pr-122317 is now running

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

craterbot · 2024-03-20T04:51:15Z

🎉 Experiment pr-122317 is completed!
📊 34 regressed and 1 fixed (425628 total)
📰 Open the full report.

⚠️ If you notice any spurious failure please add them to the blacklist!
ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

lcnr · 2024-04-23T13:41:42Z

@bors r+ rollup=never

bors · 2024-04-23T13:41:44Z

📌 Commit 8995c2c has been approved by lcnr

It is now in the queue for this repository.

bors · 2024-04-23T14:07:08Z

⌛ Testing commit 8995c2c with merge cd90d5c...

bors · 2024-04-23T16:11:00Z

☀️ Test successful - checks-actions
Approved by: lcnr
Pushing cd90d5c to master...

rust-timer · 2024-04-23T17:26:31Z

Finished benchmarking commit (cd90d5c): comparison URL.

Overall result: ❌ regressions - ACTION NEEDED

Next Steps: If you can justify the regressions found in this perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please open an issue or create a new PR that fixes the regressions, add a comment linking to the newly created issue or PR, and then add the perf-regression-triaged label to this PR.

@rustbot label: +perf-regression
cc @rust-lang/wg-compiler-performance

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.5%	[0.2%, 1.3%]	38
Regressions ❌ (secondary)	4.2%	[0.5%, 23.6%]	39
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.5%	[0.2%, 1.3%]	38

Max RSS (memory usage)

Results

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)	2.7%	[2.7%, 2.7%]	1
Improvements ✅ (primary)	-1.4%	[-1.4%, -1.4%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.4%	[-1.4%, -1.4%]	1

Cycles

Results

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)	1.5%	[1.3%, 1.6%]	2
Regressions ❌ (secondary)	6.7%	[2.1%, 25.2%]	23
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.5%	[1.3%, 1.6%]	2

Binary size

Results

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)	0.2%	[0.2%, 0.2%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[0.2%, 0.2%]	1

Bootstrap: 673.699s -> 674.88s (0.18%)
Artifact size: 316.17 MiB -> 316.16 MiB (-0.00%)

compiler-errors · 2024-04-23T18:40:37Z

checking perf in #124303

Mark-Simulacrum · 2024-04-29T12:59:50Z

Marking this as triaged -- looks like attempts were made to improve performance in #124303 but did not pan out. The regressions are mostly pretty small with the exception of a stress test for exactly(?) this code.

…=<try> Relate receiver invariantly in method probe for `Mode::Path` Reverts rust-lang#126128 Fixes the part of rust-lang#122317 which always used subtyping instead of eq Fixes rust-lang#126227 (TODO: test) WIP: description r? lcnr

rustbot assigned lcnr Mar 11, 2024

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. labels Mar 11, 2024

compiler-errors commented Mar 11, 2024

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craterbot added S-waiting-on-crater Status: Waiting on a crater run to be completed. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 11, 2024

compiler-errors mentioned this pull request Mar 13, 2024

multiple applicable items in scope errors when using the new trait solver with diesel #122433

Closed

lcnr mentioned this pull request Mar 14, 2024

Recurse into args in WF even if they have escaping bound vars #122501

Closed

compiler-errors mentioned this pull request Mar 14, 2024

Crater rollup #122502

Closed

4 tasks

compiler-errors force-pushed the fulfill-method-probe branch from 3702ab1 to 35d6003 Compare March 14, 2024 18:52

craterbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-crater Status: Waiting on a crater run to be completed. labels Mar 20, 2024

compiler-errors added 6 commits April 21, 2024 20:10

Some early clean-ups in method probe

c13af7d

Use fulfillment, not evaluate, during method probe

ff4653a

Normalize xform_ret_ty after constrained

d9fec13

Check that predicate may hold BEFORE registering it in ocx

9d4f1d8

Restore error messaging

93c6c04

Use sup instead of eq when unifying self type

8995c2c

compiler-errors force-pushed the fulfill-method-probe branch from 685ba72 to 8995c2c Compare April 22, 2024 00:10

bors 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 23, 2024

bors added the merged-by-bors This PR was explicitly merged by bors. label Apr 23, 2024

bors merged commit cd90d5c into rust-lang:master Apr 23, 2024

rustbot added this to the 1.79.0 milestone Apr 23, 2024

This was referenced Apr 23, 2024

Perform autoref/autoderef on .await #111773

Closed

change method resolution to constrain hidden types instead of rejecting method candidates #123962

Merged

Add IntoIterator for Box<[T]> + edition 2024-specific lints #124097

Merged

rustbot added the perf-regression Performance regression. label Apr 23, 2024

matthiaskrgr mentioned this pull request Apr 24, 2024

ICE: entered unreachable code: encountered 'Item(Item.. due to Some(ObligationCause .. #124350

Closed

apiraino removed the to-announce Announce this issue on triage meeting label Apr 29, 2024

Mark-Simulacrum added the perf-regression-triaged The performance regression has been triaged. label Apr 29, 2024

oli-obk mentioned this pull request Jun 10, 2024

Consistently use subtyping in method resolution #126128

Merged

compiler-errors mentioned this pull request Aug 14, 2024

Relate receiver invariantly in method probe for Mode::Path #129073

Merged

compiler-errors mentioned this pull request Jul 30, 2025

Code that used to error on Rust 1.77 causes a compiler hang on 1.78 and later #144696

Open

Use fulfillment in method probe, not evaluation #122317

Use fulfillment in method probe, not evaluation #122317

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Overall result: ❌ regressions - ACTION NEEDED

Instruction count

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Binary size

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