Rollup of 20 pull requests by jhpratt · Pull Request #161458 · rust-lang/rust

jhpratt · 2026-08-21T12:43:56Z

Successful merges:

move some attribute related structs out of rustc_attr_ir #161259 (move some attribute related structs out of rustc_attr_ir)
delegation: simplify matches on FnKind, minor refactorings #160853 (delegation: simplify matches on FnKind, minor refactorings)
proc_macro: add support for 16-bit targets #161161 (proc_macro: add support for 16-bit targets)
GenericArgs::types triage + possible fixes #159899 ( GenericArgs::types triage + possible fixes)
Use attribute parser for deprecated attribute checking #160459 (Use attribute parser for deprecated attribute checking)
Inline String::into_raw_parts and reuse from_utf16 optimization #160536 (Inline String::into_raw_parts and reuse from_utf16 optimization)
Make BorrowedCursor<'a, T> covariant in 'a and drop an indirection #160563 (Make BorrowedCursor<'a, T> covariant in 'a and drop an indirection)
Clarify str::split_at docs #160595 (Clarify str::split_at docs)
Optimize linked list iterator performance #160813 (Optimize linked list iterator performance)
doc: document safety requirements for core WTF-8 #161271 (doc: document safety requirements for core WTF-8)
LLVM 24: configure float-abi via module flag #161317 (LLVM 24: configure float-abi via module flag)
Only suggest RUST_MIN_STACK if maybe stack overflow #161320 (Only suggest RUST_MIN_STACK if maybe stack overflow)
Add regression test for confusing lifetime error message issue #161369 (Add regression test for confusing lifetime error message issue)
Configure LLM policy URL for triagebot #161393 (Configure LLM policy URL for triagebot)
splat-fn-ptr-ptr-tuple.rs: add let to avoid UB #161403 (splat-fn-ptr-ptr-tuple.rs: add let to avoid UB)
Add back tests/rustdoc-gui/notable-trait.goml test #161409 (Add back tests/rustdoc-gui/notable-trait.goml test)
Fix rustdoc remapping documentation scope documentation #161410 (Fix rustdoc remapping documentation scope documentation)
Update expect messages in path docs to better follow guidelines #161415 (Update expect messages in path docs to better follow guidelines)
Change triagebot backport to ping T-libs-fcp #161438 (Change triagebot backport to ping T-libs-fcp)
Add regression test for dead code on type alias used in impl self type #161442 (Add regression test for dead code on type alias used in impl self type)

Failed merges:

Remove RegionExt; move methods to Region in rustc_type_ir #160509 (Remove RegionExt; move methods to Region in rustc_type_ir)

r? @ghost

Create a similar rollup

…rom_utf16be

…benchmarking

- be explicit when only needing types of `GenericArgs`

jhpratt · 2026-08-21T12:44:16Z

@bors r+ p=5

@bors try jobs=dist-various-1,test-various,x86_64-gnu-aux,x86_64-gnu-llvm-21-3,x86_64-msvc-1,aarch64-apple-,x86_64-mingw-1,i686-msvc-

rust-bors · 2026-08-21T12:44:19Z

📌 Commit f2667ec has been approved by jhpratt

It is now in the queue for this repository.

Rollup of 20 pull requests try-job: dist-various-1 try-job: test-various try-job: x86_64-gnu-aux try-job: x86_64-gnu-llvm-21-3 try-job: x86_64-msvc-1 try-job: aarch64-apple-* try-job: x86_64-mingw-1 try-job: i686-msvc-*

rust-bors · 2026-08-21T15:41:25Z

☀️ Try build successful (CI)
Build commit: bb2190b (bb2190bd2956f0f586fc078acc86bebc3916a03f)
Base parent: 526c36b (526c36b4c477994b7905ec6a084d6150e49076f5)

rust-bors · 2026-08-21T18:30:57Z

☀️ Test successful - CI
Approved by: jhpratt
Duration: 3h 8m 9s
Pushing a872286 to main...

github-actions · 2026-08-21T18:33:46Z

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 b662191 (parent) -> a872286 (this PR)

Test differences

Show 364 test diffs

Stage 1

[codegen] tests/codegen-llvm/float/abi-flag.rs#aarch64sf: [missing] -> ignore (ignored when the LLVM version 23.1.0 is older than 24.0.0) (J2)
[codegen] tests/codegen-llvm/float/abi-flag.rs#armhf: [missing] -> ignore (ignored when the LLVM version 23.1.0 is older than 24.0.0) (J2)
[codegen] tests/codegen-llvm/float/abi-flag.rs#armsf: [missing] -> ignore (ignored when the LLVM version 23.1.0 is older than 24.0.0) (J2)
[codegen] tests/codegen-llvm/float/abi-flag.rs#aarch64sf: [missing] -> ignore (ignored when the LLVM version 21.1.2 is older than 24.0.0) (J3)
[codegen] tests/codegen-llvm/float/abi-flag.rs#armhf: [missing] -> ignore (ignored when the LLVM version 21.1.2 is older than 24.0.0) (J3)
[codegen] tests/codegen-llvm/float/abi-flag.rs#armsf: [missing] -> ignore (ignored when the LLVM version 21.1.2 is older than 24.0.0) (J3)
[codegen] tests/codegen-llvm/float/abi-flag.rs#aarch64sf: [missing] -> ignore (ignored when the LLVM version 22.1.2 is older than 24.0.0) (J4)
[codegen] tests/codegen-llvm/float/abi-flag.rs#armhf: [missing] -> ignore (ignored when the LLVM version 22.1.2 is older than 24.0.0) (J4)
[codegen] tests/codegen-llvm/float/abi-flag.rs#armsf: [missing] -> ignore (ignored when the LLVM version 22.1.2 is older than 24.0.0) (J4)
[ui (polonius)] tests/ui/impl-trait/confusing-lifetime-error-issue-79033.rs: [missing] -> pass (J6)
[ui (polonius)] tests/ui/lint/dead-code/type-alias-used-in-impl-59333.rs: [missing] -> pass (J6)
[ui] tests/ui/impl-trait/confusing-lifetime-error-issue-79033.rs: [missing] -> pass (J8)
[ui] tests/ui/lint/dead-code/type-alias-used-in-impl-59333.rs: [missing] -> pass (J8)
linked_list::bench_iter_count: [missing] -> pass (J10)

Stage 2

[ui] tests/ui/impl-trait/confusing-lifetime-error-issue-79033.rs: [missing] -> pass (J0)
[ui] tests/ui/lint/dead-code/type-alias-used-in-impl-59333.rs: [missing] -> pass (J0)
[codegen] tests/codegen-llvm/float/abi-flag.rs#aarch64sf: [missing] -> ignore (ignored when the LLVM version 22.1.2 is older than 24.0.0) (J1)
[codegen] tests/codegen-llvm/float/abi-flag.rs#armhf: [missing] -> ignore (ignored when the LLVM version 22.1.2 is older than 24.0.0) (J1)
[codegen] tests/codegen-llvm/float/abi-flag.rs#armsf: [missing] -> ignore (ignored when the LLVM version 22.1.2 is older than 24.0.0) (J1)
linked_list::bench_iter_count: [missing] -> pass (J5)
[codegen] tests/codegen-llvm/float/abi-flag.rs#aarch64sf: [missing] -> ignore (ignored when the LLVM version 21.1.2 is older than 24.0.0) (J7)
[codegen] tests/codegen-llvm/float/abi-flag.rs#armhf: [missing] -> ignore (ignored when the LLVM version 21.1.2 is older than 24.0.0) (J7)
[codegen] tests/codegen-llvm/float/abi-flag.rs#armsf: [missing] -> ignore (ignored when the LLVM version 21.1.2 is older than 24.0.0) (J7)
[codegen] tests/codegen-llvm/float/abi-flag.rs#aarch64sf: [missing] -> ignore (ignored when the LLVM version 23.1.0 is older than 24.0.0) (J9)
[codegen] tests/codegen-llvm/float/abi-flag.rs#armhf: [missing] -> ignore (ignored when the LLVM version 23.1.0 is older than 24.0.0) (J9)
[codegen] tests/codegen-llvm/float/abi-flag.rs#armsf: [missing] -> ignore (ignored when the LLVM version 23.1.0 is older than 24.0.0) (J9)

Additionally, 338 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 a872286d0a1873caec0291ed4304de3170adbe16 --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: 10m 18s -> 18m 49s (+82.7%)
x86_64-gnu-gcc-core-tests: 10m 57s -> 17m 41s (+61.5%)
x86_64-gnu-llvm-22-3: 1h 14m -> 1h 53m (+52.1%)
x86_64-gnu-llvm-22-2: 1h 1m -> 1h 33m (+51.7%)
x86_64-gnu-next-trait-solver-polonius: 41m 59s -> 1h 2m (+50.0%)
x86_64-gnu-llvm-21: 39m 14s -> 57m 39s (+46.9%)
i686-gnu-nopt-1: 1h 32m -> 2h 14m (+46.2%)
dist-i586-gnu-i586-i686-musl: 19m 35s -> 27m 22s (+39.7%)
x86_64-rust-for-linux: 45m 45s -> 59m 31s (+30.1%)
dist-s390x-linux: 1h 31m -> 1h 6m (-27.1%)

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 · 2026-08-21T19:30:34Z

Finished benchmarking commit (a872286): comparison URL.

Overall result: ❌ regressions - please read:

Our benchmarks found a performance regression caused by this PR.
This might be an actual regression, but it can also be just noise.

Next Steps:

If the regression was expected or you think it can be justified,
please write a comment with sufficient written justification, and add
@rustbot label: +perf-regression-triaged to it, to mark the regression as triaged.
If you think that you know of a way to resolve the regression, try to create
a new PR with a fix for the regression.
If you do not understand the regression or you think that it is just noise,
you can ask the @rust-lang/wg-compiler-performance working group for help (members of this group
were already notified of this PR).

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

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)	1.1%	[1.1%, 1.1%]	1
Regressions ❌ (secondary)	0.1%	[0.1%, 0.1%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.1%	[1.1%, 1.1%]	1

Max RSS (memory usage)

Results (primary 9.1%, secondary 7.9%)

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

	mean	range	count
Regressions ❌ (primary)	9.1%	[9.1%, 9.1%]	1
Regressions ❌ (secondary)	7.9%	[7.9%, 7.9%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	9.1%	[9.1%, 9.1%]	1

Cycles

Results (primary -2.4%, 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)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.4%	[-2.4%, -2.4%]	1
Improvements ✅ (secondary)	-2.5%	[-3.2%, -1.8%]	2
All ❌✅ (primary)	-2.4%	[-2.4%, -2.4%]	1

Binary size

Results (primary 0.1%, secondary -0.3%)

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

	mean	range	count
Regressions ❌ (primary)	1.3%	[0.1%, 5.0%]	4
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.2%	[-0.6%, -0.1%]	14
Improvements ✅ (secondary)	-0.3%	[-0.4%, -0.0%]	49
All ❌✅ (primary)	0.1%	[-0.6%, 5.0%]	18

Bootstrap: 470.067s -> 468.499s (-0.33%)
Artifact size: 400.02 MiB -> 400.07 MiB (0.01%)

rust-bors · 2026-08-21T19:38:01Z

📌 Perf builds for each rolled up PR:

PR#	Message	Perf Build Sha
#161259	move some attribute related structs out of rustc_attr_ir	`77433e46848ae54b025820989598fd3d76bcc08f` (link)
#160853	delegation: simplify matches on `FnKind`, minor refactorings	`50d6ab8c478fe33684432cce9dfa06def3970f4f` (link)
#161161	proc_macro: add support for 16-bit targets	`37fdff8f236ebcff4c0f9d59e0627480a38903e9` (link)
#159899	`GenericArgs::types` triage + possible fixes	`b9e823b78dc981c5974c2fa89bdaabd327b12829` (link)
#160459	Use attribute parser for `deprecated` attribute checking	`0ba17bcdc70201e3755c35c8d4fd62fbd2ec8727` (link)
#160536	Inline `String::into_raw_parts` and reuse `from_utf16` opti…	`839342e5290e97e47e6f1d7753d7b09d07387e23` (link)
#160563	Make `BorrowedCursor<'a, T>` covariant in `'a` and drop an …	`039ca27bd5bf1d5ef0938b292eecf8ddb6d9c71b` (link)
#160595	Clarify `str::split_at` docs	`03f64b79854e8cf65ce37c013d61955a50c147d8` (link)
#160813	Optimize linked list iterator performance	`812662004a732adbf0c5071e79629572f9feb1c0` (link)
#161271	doc: document safety requirements for core WTF-8	`b5fd21b6aa966536cd431f94a22bc0eee5e126bf` (link)
#161317	LLVM 24: configure float-abi via module flag	`31639bda0fab51088ad755d75f0d068a8e52002a` (link)
#161320	Only suggest `RUST_MIN_STACK` if maybe stack overflow	`5d2a569e5f73b3ac5ca0ed8d1322841ad82a9db5` (link)
#161369	Add regression test for confusing lifetime error message is…	`0b61f33fb5cdb7cf139ea12c4b1f85e271b6e5e8` (link)
#161393	Configure LLM policy URL for triagebot	`dec91e2ece7c9ca32c97573ce0cf612a4d49e408` (link)
#161403	splat-fn-ptr-ptr-tuple.rs: add `let` to avoid UB	`feda66fbc721c670581273f14b79ac3ab60acc27` (link)
#161409	Add back `tests/rustdoc-gui/notable-trait.goml` test	`10286c461a6efe694fdad8942e29abef56c93492` (link)
#161410	Fix rustdoc remapping `documentation` scope documentation	`72f049565a73f74b1b697a7f06dc68ef3c8f67f3` (link)
#161415	Update expect messages in path docs to better follow guidel…	`ea81a2303d540494032630ea04625034d1ef267d` (link)
#161438	Change triagebot backport to ping T-libs-fcp	`4a01dd4c9d80223358f902d30eb09784285ff2e2` (link)
#161442	Add regression test for dead code on type alias used in imp…	`c6e5a9a591bd4cc279033b2d81e1d31aad87ecae` (link)

parent commit: b66219142c

In the case of a perf regression, run the following command for each PR you suspect might be the cause: @rust-timer build $SHA

fereidani and others added 30 commits August 5, 2026 05:51

perf: reuse the same optimization as from_utf16 in from_utf16le and f…

94b7897

…rom_utf16be

perf: inline the String::into_raw_parts

f741ac8

Clarify str split doc

d9e5ec7

Optimize linked list iterator performance

4ded686

Implement TrustedLen for LinkedList iterators

acb3ed6

Improve linked list benchmarks to use black_box and better logic for …

3f07563

…benchmarking

doc: document safety requirements for core WTF-8

c215bed

- implement GenericArgs::terms and use where needed.

558dbb6

- be explicit when only needing types of `GenericArgs`

use next().and_then(as_type) instead of filter_map(as_type).nth(0)

715bd31

Only suggest RUST_MIN_STACK if stack overflow

7b7dffb

LLVM 24: configure float-abi via module flag

4c28ae2

Add regression test for confusing lifetime error message issue

d6e1d0e

Add regression test for dead_code on type alias used in impl self type

8ba038c

Configure LLM policy URL for triagebot

0ff906a

splat-fn-ptr-ptr-tuple.rs: add let to avoid UB

9da8a55

Add back tests/rustdoc-gui/notable-trait.goml test

d15096b

Fix rustdoc remapping documentation scope documentation

274e97c

Update expect messages in path docs to better follow guidelines

176a865

Change triagebot backport to ping T-libs-fcp

ab35013

Move Limit

589bb91

move SanitizerSet

2a20dfa

make nightly feature

29dba3e

invert dependency on rustc_error_messages

f713bb2

move CrateType

38af4a2

Move NativeLibKind

8d970ff

move CollapseMacroDebuginfo

7bec351

Add crate docs

587412a

bless bootstrap

601e9d6

Fix tools

12278ac

fix miri

9e9c3b1

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 Aug 21, 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 21, 2026

rust-bors Bot merged commit a872286 into rust-lang:main Aug 21, 2026
15 checks passed

rustbot added this to the 1.100.0 milestone Aug 21, 2026

rustbot added the perf-regression Performance regression. label Aug 21, 2026

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Rollup of 20 pull requests - #161458

Rollup of 20 pull requests#161458
rust-bors[bot] merged 58 commits into
rust-lang:mainfrom
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Test differences

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Stage 2

Job duration changes

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rust-timer commented Aug 21, 2026

Overall result: ❌ regressions - please read:

Instruction count

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Cycles

Binary size

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