Rollup of 3 pull requests by jhpratt · Pull Request #159166 · rust-lang/rust

jhpratt · 2026-07-12T04:03:12Z

Successful merges:

mut restriction lowering #159125 (mut restriction lowering)
compiler: redescribe llvmlike_vector_align as rust_vector_align #159154 (compiler: redescribe llvmlike_vector_align as rust_vector_align)
Better comment the struct used by {read,write}_unaligned #159157 (Better comment the struct used by {read,write}_unaligned)

Failed merges:

Apply MCP 1003 and move diagnostics.rs into its own module #158732 (Apply MCP 1003 and move diagnostics.rs into its own module)

This is mostly a cosmetic change. The current form of this function tends to mislead people to assume it is implicitly "correct" in various ways by invoking LLVM as an authority. It is only sort-of correct. More specifically, LLVM mostly doesn't care, and neither do we, except when it comes to FFI. So, we have an arbitrary algorithm that works usefully in most cases. It is not inherently more correct than other arbitrary algorithms, so spell this out and weaken its contract.

@Urgau

…ering, r=jhpratt,Urgau `mut` restriction lowering This PR is part of the ongoing work to implement `mut` restrictions proposed in [RFC 3323](https://rust-lang.github.io/rfcs/3323-restrictions.html), and linked to a [GSoC proposal](https://rust-lang.zulipchat.com/#narrow/channel/421156-gsoc/topic/Project.3A.20Implementing.20impl.20and.20mut.20restrictions/with/592352432). It implements path resolution for `mut` restrictions and lowers the resolved information to HIR. Tracking issue: rust-lang#105077 r? @Urgau cc @jhpratt

…tor-align, r=scottmcm compiler: redescribe llvmlike_vector_align as rust_vector_align This is mostly a cosmetic change. The current form of this function tends to mislead people to assume it is implicitly "correct" in various ways by invoking LLVM as an authority. It is only sort-of correct. More specifically, LLVM mostly doesn't care, and neither do we, except when it comes to FFI. So, we have an arbitrary algorithm that works usefully in most cases. It is not inherently more correct than other arbitrary algorithms, so spell this out and weaken its contract.

@RalfJung

…uct, r=joshtriplett Better comment the struct used by `{read,write}_unaligned` To address rust-lang#159033 (comment) r? @RalfJung

jhpratt · 2026-07-12T04:04:45Z

@bors r+ rollup=never p=5

rust-bors · 2026-07-12T04:04:48Z

📌 Commit a768871 has been approved by jhpratt

It is now in the queue for this repository.

rust-bors · 2026-07-12T08:23:09Z

☀️ Test successful - CI
Approved by: jhpratt
Duration: 3h 15m 38s
Pushing b69e089 to main...

rust-timer · 2026-07-12T08:24:04Z

📌 Perf builds for each rolled up PR:

PR#	Message	Perf Build Sha
#159125	`mut` restriction lowering	`2ecfd42a72176a670240347cf556a2eacba16318` (link)
#159154	compiler: redescribe llvmlike_vector_align as rust_vector_a…	`4b8586683fff1c3d1d3e19581cbd7a066ff938b2` (link)
#159157	Better comment the struct used by `{read,write}_unaligned`	`094fd17858f325e2902c4fae2a836aede03b5873` (link)

previous master: be8e82435e

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

github-actions · 2026-07-12T08:26:25Z

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 be8e824 (parent) -> b69e089 (this PR)

Test differences

Show 19 test diffs

Stage 1

[pretty] tests/pretty/hir-impl-restriction.rs: [missing] -> pass (J1)
[pretty] tests/pretty/hir-mut-restriction.rs: [missing] -> pass (J1)
[ui (polonius)] tests/ui/mut-restriction/restriction-resolution-errors.rs: [missing] -> pass (J2)
[ui] tests/ui/mut-restriction/restriction-resolution-errors.rs: [missing] -> pass (J4)

Stage 2

[pretty] tests/pretty/hir-impl-restriction.rs: [missing] -> pass (J0)
[pretty] tests/pretty/hir-mut-restriction.rs: [missing] -> pass (J0)
[ui] tests/ui/mut-restriction/restriction-resolution-errors.rs: [missing] -> pass (J3)

Additionally, 12 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 b69e089eb3ec9976ddec602bf18c3d6a8ce72512 --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-gcc-core-tests: 10m 11s -> 14m 45s (+44.7%)
x86_64-gnu-aux: 2h 2m -> 2h 56m (+44.0%)
i686-gnu-2: 1h 11m -> 1h 42m (+42.7%)
x86_64-gnu-next-trait-solver-polonius: 43m 39s -> 1h 1m (+41.9%)
x86_64-msvc-2: 1h 49m -> 2h 29m (+36.3%)
x86_64-msvc-ext1: 1h 40m -> 2h 11m (+30.7%)
x86_64-mingw-2: 2h 2m -> 2h 39m (+30.0%)
dist-x86_64-mingw: 1h 57m -> 2h 25m (+23.6%)
aarch64-apple-macos-26: 2h 33m -> 3h 9m (+23.2%)
x86_64-gnu-llvm-22-2: 1h 21m -> 1h 39m (+21.9%)

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 · 2026-07-12T17:03:32Z

Finished benchmarking commit (b69e089): 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)	-	-	0
Regressions ❌ (secondary)	0.1%	[0.0%, 0.2%]	11
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.1%	[-0.1%, -0.1%]	1
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

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

Cycles

Results (primary -2.5%, secondary -2.6%)

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)	-2.5%	[-2.6%, -2.3%]	2
Improvements ✅ (secondary)	-2.6%	[-2.6%, -2.6%]	1
All ❌✅ (primary)	-2.5%	[-2.6%, -2.3%]	2

Binary size

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

Bootstrap: 488.088s -> 489.358s (0.26%)
Artifact size: 389.26 MiB -> 389.32 MiB (0.02%)

Kobzol · 2026-07-12T17:05:33Z

Regression caused by #159125, a tiny regression in the include-blob stress test, no further action needed.

@rustbot label: +perf-regression-triaged

CoCo-Japan-pan and others added 12 commits July 11, 2026 13:34

Resolve paths for mut restrictions

cf3fad1

Add UI tests for path resolution errors of mut restrictions

7918a49

Lower mut restriction to HIR

3ee2de8

Pretty print HIR's mut restriction

040c434

Bless UI test for input-stats.rs

937fadd

Add HIR pretty print tests for impl and mut restrictions

62c026d

Add pub(..) and unsafe to HIR pretty print tests for mut restriction

c060b6d

Better comment the struct used by {read,write}_unaligned

b098a47

Rollup merge of rust-lang#159157 - scottmcm:clearer-ptr-unaligned-str…

a768871

…uct, r=joshtriplett Better comment the struct used by `{read,write}_unaligned` To address rust-lang#159033 (comment) r? @RalfJung

rust-bors Bot added the rollup A PR which is a rollup label Jul 12, 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. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Jul 12, 2026

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 Jul 12, 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 Jul 12, 2026

rust-bors Bot merged commit b69e089 into rust-lang:main Jul 12, 2026
14 checks passed

rustbot added this to the 1.99.0 milestone Jul 12, 2026

This was referenced Jul 12, 2026

Allow BackendRepr::Scalar for repr(Rust, packed) structs [MCP1007] #159033

Open

Apply MCP 1003 and move diagnostics.rs into its own module #158732

Merged

rustbot added the perf-regression Performance regression. label Jul 12, 2026

rustbot added the perf-regression-triaged The performance regression has been triaged. label Jul 12, 2026

jhpratt deleted the rollup-l3XyKzC branch July 12, 2026 20:26

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Rollup of 3 pull requests#159166

Rollup of 3 pull requests#159166
rust-bors[bot] merged 12 commits into
rust-lang:mainfrom
jhpratt:rollup-l3XyKzC

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Test differences

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Stage 2

Job duration changes

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rust-timer commented Jul 12, 2026

Overall result: ❌ regressions - please read:

Instruction count

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Cycles

Binary size

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