Use rigidness marker in fast_reject by adwinwhite · Pull Request #158438 · rust-lang/rust

adwinwhite · 2026-06-26T09:44:39Z

Make use of rigidness marker to reject rigid-alias-non-alias or incompatible rigid-alias-rigid-alias relating.

r? lcnr

adwinwhite · 2026-06-26T09:45:45Z

Use rigidness marker in fast_reject

rust-bors · 2026-06-26T11:53:09Z

☀️ Try build successful (CI)
Build commit: 011f366 (011f366512f7bbff9fbab7fb3feb29337c51e2cd)
Base parent: 40557f6 (40557f6225e337d68c8d4f086557ce54135f5dd9)

lcnr · 2026-06-26T12:03:37Z

+            // If the rigid alias doesn't contain any param that can be instantiated with
+            // infer var, we still treat it as rigid.
+            ty::Alias(ty::IsRigid::Yes, _)
+                if !(INSTANTIATE_RHS_WITH_INFER && rhs.has_non_region_param()) => {}


why the has_non_region_param()?

Is there anything we incorrectly reject if we don't do this?

View changes since the review

Oh, I guess it's unnecessary. Being rigid should imply the alias contains params.

lcnr · 2026-06-26T12:05:38Z

+            // If the rigid alias doesn't contain any param that can be instantiated with
+            // infer var, we still treat it as rigid.
+            ty::Alias(ty::IsRigid::Yes, lhs_alias)
+                if !(INSTANTIATE_RHS_WITH_INFER && lhs.has_non_region_param()) =>


INSTANTIATE_LHS_WITH_INFER here 😅

and I would move the INSTANTIATE_LHS_WITH_INFER into the match arm, s opretty much exactly copy ty::Param handling

View changes since the review

lcnr · 2026-06-26T12:05:52Z

            // projections can unify with other stuff.
-            //
-            // Looking forward to lazy normalization this is the safer strategy anyways.
            ty::Alias(..) => true,


Suggested change

ty::Alias(..) => true,

ty::Alias(ty::IsRigid::No) => true,

View changes since the review

rust-timer · 2026-06-26T12:41:03Z

Finished benchmarking commit (011f366): comparison URL.

Overall result: ✅ improvements - no action needed

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

@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
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.5%	[-0.5%, -0.5%]	1
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

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

Cycles

Results (primary -2.2%)

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

Binary size

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

Bootstrap: 482.935s -> 483.593s (0.14%)
Artifact size: 392.98 MiB -> 393.06 MiB (0.02%)

adwinwhite · 2026-06-26T13:01:57Z

@bors try @rust-timer queue

Use rigidness marker in fast_reject

rust-bors · 2026-06-26T15:09:26Z

☀️ Try build successful (CI)
Build commit: 7bc6cb5 (7bc6cb5944b7e4f141bca319eefc430354db49ce)
Base parent: 40557f6 (40557f6225e337d68c8d4f086557ce54135f5dd9)

rust-timer · 2026-06-26T16:03:02Z

Finished benchmarking commit (7bc6cb5): comparison URL.

Overall result: ✅ improvements - no action needed

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

@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
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.4%	[-0.4%, -0.4%]	1
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 3.2%, secondary 2.5%)

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

	mean	range	count
Regressions ❌ (primary)	3.2%	[3.2%, 3.2%]	1
Regressions ❌ (secondary)	2.5%	[2.5%, 2.5%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	3.2%	[3.2%, 3.2%]	1

Cycles

Results (primary -2.1%, 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)	-	-	0
Improvements ✅ (primary)	-2.1%	[-2.1%, -2.1%]	1
Improvements ✅ (secondary)	-2.4%	[-2.4%, -2.4%]	1
All ❌✅ (primary)	-2.1%	[-2.1%, -2.1%]	1

Binary size

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

Bootstrap: 482.935s -> 485.508s (0.53%)
Artifact size: 392.98 MiB -> 393.53 MiB (0.14%)

lcnr · 2026-06-26T17:13:12Z

hmm, unfortunately small effect

@bors r+ rollup=iffy feels worth to rollup

rust-bors · 2026-06-26T17:13:15Z

📌 Commit b049d2b has been approved by lcnr

It is now in the queue for this repository.

🌲 The tree is currently closed for pull requests below priority 1. This pull request will be tested once the tree is reopened.

…uwer Rollup of 15 pull requests Successful merges: - #153697 (Add arg splat experiment initial tuple impl) - #158360 (Various borrowck cleanups and param_env/opaque_types_defined_by query simplifications for typeck children) - #158438 (Use rigidness marker in fast_reject) - #157127 (cg_LLVM: Stop needing an alloca for volatile loads) - #158376 (Suggest `>=` for `=>` typo in closure and call argument positions) - #158185 (perf: Make stable_crate_ids reads lock-free after crate loading) - #158244 (Attribute docs `deprecated` , `warn`, `allow`, `cfg`, `deny`, and `forbid` ) - #158355 (Fixup the refactoring errors in #156246) - #158361 (Move `check_ffi_pure` into the attribute parser) - #158382 (Add safety section for SliceIndex::get_unchecked(mut)) - #158399 (std: truncate thread names on NetBSD) - #158418 (Eliminate double length check in `Vec::into_array`) - #158430 (Guard clone suggestion against empty obligation errors) - #158446 (Update Enzyme submodule) - #158448 (Cleanup `NumBuffer` comment and replace `ilog(10)` with `ilog10()`)

Rollup merge of #158438 - adwinwhite:deep-reject, r=lcnr Use rigidness marker in fast_reject Make use of rigidness marker to reject rigid-alias-non-alias or incompatible rigid-alias-rigid-alias relating. r? lcnr

…uwer Rollup of 15 pull requests Successful merges: - rust-lang/rust#153697 (Add arg splat experiment initial tuple impl) - rust-lang/rust#158360 (Various borrowck cleanups and param_env/opaque_types_defined_by query simplifications for typeck children) - rust-lang/rust#158438 (Use rigidness marker in fast_reject) - rust-lang/rust#157127 (cg_LLVM: Stop needing an alloca for volatile loads) - rust-lang/rust#158376 (Suggest `>=` for `=>` typo in closure and call argument positions) - rust-lang/rust#158185 (perf: Make stable_crate_ids reads lock-free after crate loading) - rust-lang/rust#158244 (Attribute docs `deprecated` , `warn`, `allow`, `cfg`, `deny`, and `forbid` ) - rust-lang/rust#158355 (Fixup the refactoring errors in rust-lang/rust#156246) - rust-lang/rust#158361 (Move `check_ffi_pure` into the attribute parser) - rust-lang/rust#158382 (Add safety section for SliceIndex::get_unchecked(mut)) - rust-lang/rust#158399 (std: truncate thread names on NetBSD) - rust-lang/rust#158418 (Eliminate double length check in `Vec::into_array`) - rust-lang/rust#158430 (Guard clone suggestion against empty obligation errors) - rust-lang/rust#158446 (Update Enzyme submodule) - rust-lang/rust#158448 (Cleanup `NumBuffer` comment and replace `ilog(10)` with `ilog10()`)

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 Jun 26, 2026

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rust-bors Bot pushed a commit that referenced this pull request Jun 26, 2026

Auto merge of #158438 - adwinwhite:deep-reject, r=<try>

011f366

Use rigidness marker in fast_reject

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lcnr reviewed Jun 26, 2026

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jun 26, 2026

adwinwhite force-pushed the deep-reject branch from 0c2b344 to 4320308 Compare June 26, 2026 12:51

rustbot assigned lcnr Jun 26, 2026

make use of rigidness marker in fast_reject

b049d2b

adwinwhite force-pushed the deep-reject branch from 4320308 to b049d2b Compare June 26, 2026 12:56

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rust-bors Bot pushed a commit that referenced this pull request Jun 26, 2026

Auto merge of #158438 - adwinwhite:deep-reject, r=<try>

7bc6cb5

Use rigidness marker in fast_reject

adwinwhite marked this pull request as ready for review June 26, 2026 13:02

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 Jun 26, 2026

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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 Jun 26, 2026

JonathanBrouwer mentioned this pull request Jun 26, 2026

Rollup of 15 pull requests #158455

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rust-bors Bot merged commit 8002964 into rust-lang:main Jun 27, 2026
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rustbot added this to the 1.98.0 milestone Jun 27, 2026

lcnr mentioned this pull request Jun 29, 2026

Internal Tracking Issue for normalization redesign #155345

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rust-timer commented Jun 26, 2026

Overall result: ✅ improvements - no action needed

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rust-timer commented Jun 26, 2026

Overall result: ✅ improvements - no action needed

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adwinwhite commented Jun 26, 2026 •

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