Rollup of 6 pull requests #144637

Zalathar · 2025-07-29T13:50:39Z

Successful merges:

coverage: Treat #[automatically_derived] as #[coverage(off)] #144560 (coverage: Treat #[automatically_derived] as #[coverage(off)])
Simplify align_of_val::<[T]>(…) → align_of::<T>() #144566 (Simplify align_of_val::<[T]>(…) → align_of::<T>())
expand: Micro-optimize prelude injection #144587 (expand: Micro-optimize prelude injection)
Account for .yield in illegal postfix operator message #144589 (Account for .yield in illegal postfix operator message)
Make resolve_fn_signature responsible for its own rib. #144615 (Make resolve_fn_signature responsible for its own rib.)
Fix typo in DropGuard doc #144634 (Fix typo in DropGuard doc)

r? @ghost
@rustbot modify labels: rollup

Use `splice` to avoid shifting the other items twice. Put `extern crate std;` first so it's already resolved when we resolve `::std::prelude::rust_20XX`.

This patch also prepares the affected code in `coverage_attr_on` for some subsequent changes.

…errors coverage: Treat `#[automatically_derived]` as `#[coverage(off)]` One of the contributing factors behind rust-lang#141577 (comment) was the presence of derive-macro-generated code containing nested closures. Coverage instrumentation already has a heuristic for skipping code marked with `#[automatically_derived]` (rust-lang#120185), because derived code is usually not worth instrumenting, and also has a tendency to trigger vexing edge-case bugs in coverage instrumentation or coverage codegen. However, the existing heuristic only applied to the associated items directly within an auto-derived impl block, and had no effect on closures or nested items within those associated items. This PR therefore extends the search for `#[coverage(..)]` attributes to also treat `#[automatically_derived]` as an implied `#[coverage(off)]` for the purposes of coverage instrumentation. --- This change doesn’t rule out an entire category of bugs, because it only affects code that actually uses the auto-derived attribute. But it should reduce the overall chance of edge-case macro span bugs being observed in the wild.

Simplify `align_of_val::<[T]>(…)` → `align_of::<T>()` I spotted this while working on the inliner (rust-lang#144561). In particular, if [`Layout::for_value`](https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.for_value) inlines, then it can be pretty easy to end up with an `align_of_val::<[T]>` today (demo: <https://rust.godbolt.org/z/Tesnscj4a>) where we can save at least a block, if not more, by using the version that's an rvalue and not a call.

…cote expand: Micro-optimize prelude injection Use `splice` to avoid shifting the other items twice. Put `extern crate std;` first so it's already resolved when we resolve `::std::prelude::rust_20XX`.

…r-cast, r=petrochenkov Account for `.yield` in illegal postfix operator message Fixes rust-lang#144527

Make resolve_fn_signature responsible for its own rib. Small simplification in late resolver rib bookkeeping. r? `@petrochenkov`

Fix typo in `DropGuard` doc Follows-up rust-lang#144236 (I happened to see the typo yesterday but didn’t think it should delay the PR’s merge so I kept quiet, sorryyyyy).

Zalathar · 2025-07-29T13:50:54Z

@bors r+ rollup=never p=5

bors · 2025-07-29T13:50:56Z

📌 Commit 7088bf5 has been approved by Zalathar

It is now in the queue for this repository.

bors · 2025-07-29T13:52:44Z

⌛ Testing commit 7088bf5 with merge ac0cb05...

bors · 2025-07-29T17:38:41Z

☀️ Test successful - checks-actions
Approved by: Zalathar
Pushing ac0cb05 to master...

rust-timer · 2025-07-29T17:40:27Z

📌 Perf builds for each rolled up PR:

PR#	Message	Perf Build Sha
#144560	coverage: Treat `#[automatically_derived]` as `#[coverage(o…	`941f72863d332601c4fe80a7aaa1f9ddcb8f83e5` (link)
#144566	Simplify `align_of_val::<[T]>(…)` → `align_of::<T>()`	`768f10f22964c8b4e1dfd6461d6e18726d20adce` (link)
#144587	expand: Micro-optimize prelude injection	`37d0e6d8f7cc3a726e436d3de31740777e480b1c` (link)
#144589	Account for `.yield` in illegal postfix operator message	`2e74bb6091ce6c9ab27c24812b51dd0f26cd4dd0` (link)
#144615	Make resolve_fn_signature responsible for its own rib.	`d9035737988b86458b541969f3d061571c085879` (link)
#144634	Fix typo in `DropGuard` doc	`d39d6e71202d3a9817880893abc1d72e6cf6ee11` (link)

previous master: 7278554d82

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 · 2025-07-29T17:42:10Z

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 7278554 (parent) -> ac0cb05 (this PR)

Test differences

Show 34 test diffs

Stage 1

[coverage-map] tests/coverage/auto-derived.rs#auto: [missing] -> pass (J2)
[coverage-map] tests/coverage/auto-derived.rs#base: [missing] -> pass (J2)
[coverage-map] tests/coverage/auto-derived.rs#on: [missing] -> pass (J2)
[coverage-run] tests/coverage/auto-derived.rs#auto: [missing] -> ignore (ignored when the profiler runtime is not available) (J2)
[coverage-run] tests/coverage/auto-derived.rs#base: [missing] -> ignore (ignored when the profiler runtime is not available) (J2)
[coverage-run] tests/coverage/auto-derived.rs#on: [missing] -> ignore (ignored when the profiler runtime is not available) (J2)
[mir-opt] tests/mir-opt/instsimplify/align_of_slice.rs: [missing] -> pass (J2)
[mir-opt] tests/mir-opt/pre-codegen/drop_boxed_slice.rs: [missing] -> pass (J2)
[ui] tests/ui/coroutine/postfix-yield-after-cast.rs: [missing] -> pass (J2)

Stage 2

[coverage-map] tests/coverage/auto-derived.rs#auto: [missing] -> pass (J0)
[coverage-map] tests/coverage/auto-derived.rs#base: [missing] -> pass (J0)
[coverage-map] tests/coverage/auto-derived.rs#on: [missing] -> pass (J0)
[coverage-run] tests/coverage/auto-derived.rs#auto: [missing] -> ignore (ignored when the profiler runtime is not available) (J1)
[coverage-run] tests/coverage/auto-derived.rs#base: [missing] -> ignore (ignored when the profiler runtime is not available) (J1)
[coverage-run] tests/coverage/auto-derived.rs#on: [missing] -> ignore (ignored when the profiler runtime is not available) (J1)
[mir-opt] tests/mir-opt/instsimplify/align_of_slice.rs: [missing] -> pass (J3)
[mir-opt] tests/mir-opt/pre-codegen/drop_boxed_slice.rs: [missing] -> pass (J3)
[coverage-run] tests/coverage/auto-derived.rs#auto: [missing] -> pass (J4)
[coverage-run] tests/coverage/auto-derived.rs#base: [missing] -> pass (J4)
[coverage-run] tests/coverage/auto-derived.rs#on: [missing] -> pass (J4)
[coverage-run] tests/coverage/auto-derived.rs#auto: [missing] -> ignore (ignored when cross-compiling) (J5)
[coverage-run] tests/coverage/auto-derived.rs#base: [missing] -> ignore (ignored when cross-compiling) (J5)
[coverage-run] tests/coverage/auto-derived.rs#on: [missing] -> ignore (ignored when cross-compiling) (J5)
[ui] tests/ui/coroutine/postfix-yield-after-cast.rs: [missing] -> pass (J6)

Additionally, 10 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 ac0cb05326706ef430a975aa85177e8642f2f457 --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

dist-x86_64-apple: 7728.5s -> 12529.8s (62.1%)
dist-aarch64-linux: 9008.5s -> 6008.6s (-33.3%)
dist-aarch64-apple: 7099.4s -> 5110.0s (-28.0%)
x86_64-apple-1: 8346.4s -> 6199.0s (-25.7%)
pr-check-2: 2201.4s -> 2650.0s (20.4%)
x86_64-gnu-llvm-19: 2433.0s -> 2892.8s (18.9%)
i686-gnu-nopt-1: 7277.8s -> 8426.4s (15.8%)
dist-apple-various: 4745.7s -> 4010.4s (-15.5%)
aarch64-gnu-llvm-19-2: 2246.8s -> 2533.3s (12.8%)
x86_64-rust-for-linux: 2580.2s -> 2907.6s (12.7%)

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 · 2025-07-29T20:55:55Z

Finished benchmarking commit (ac0cb05): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

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

Max RSS (memory usage)

Results (primary 0.7%)

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

	mean	range	count
Regressions ❌ (primary)	1.7%	[1.3%, 2.0%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.3%	[-1.3%, -1.3%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.7%	[-1.3%, 2.0%]	3

Cycles

Results (primary 2.4%, secondary 4.4%)

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

	mean	range	count
Regressions ❌ (primary)	2.4%	[2.4%, 2.4%]	1
Regressions ❌ (secondary)	4.4%	[4.4%, 4.4%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.4%	[2.4%, 2.4%]	1

Binary size

Results (primary 0.4%)

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

	mean	range	count
Regressions ❌ (primary)	0.4%	[0.4%, 0.4%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.4%	[0.4%, 0.4%]	1

Bootstrap: 467.638s -> 468.868s (0.26%)
Artifact size: 376.88 MiB -> 376.82 MiB (-0.02%)

panstromek · 2025-08-04T13:00:01Z

perf triage:

Looks like a spurious change in image to me. Erases gain from #144543, which was indentified as codegen unit perturbation in #144543 (comment), but this PR goes even furhter, only to return back to previous state in #144718

All these changes are in the backend part of the breakdown graph, so this truly seems like spurious codegen unit shuffling.

@rustbot label: +perf-regression-triaged

petrochenkov and others added 16 commits July 28, 2025 17:35

expand: Micro-optimize prelude injection

c56f49d

Use `splice` to avoid shifting the other items twice. Put `extern crate std;` first so it's already resolved when we resolve `::std::prelude::rust_20XX`.

Account for .yield in illegal postfix operator message

2db97b2

Make resolve_fn_signature responsible for its own rib.

be9d3bc

Add a mir-opt pre-codegen test for dropping a Box<[impl Copy]>

950a3b3

Add a MIR test for align_of_val on a slice

185b074

Simplify align_of_val::<[T]>(…) → align_of::<T>()

8ef9233

coverage: Test how #[automatically_derived] affects instrumentation

2761034

coverage: Rename CoverageStatus to CoverageAttrKind

b4d0c91

This patch also prepares the affected code in `coverage_attr_on` for some subsequent changes.

coverage: Treat #[automatically_derived] as #[coverage(off)]

682f744

Fix typo in DropGuard doc

de02a32

Rollup merge of rust-lang#144587 - petrochenkov:optstdprel, r=nnether…

3d5e2fa

…cote expand: Micro-optimize prelude injection Use `splice` to avoid shifting the other items twice. Put `extern crate std;` first so it's already resolved when we resolve `::std::prelude::rust_20XX`.

Rollup merge of rust-lang#144589 - compiler-errors:postfix-yield-afte…

b76cb79

…r-cast, r=petrochenkov Account for `.yield` in illegal postfix operator message Fixes rust-lang#144527

Rollup merge of rust-lang#144615 - cjgillot:fn-sig-rib, r=petrochenkov

9bb4087

Make resolve_fn_signature responsible for its own rib. Small simplification in late resolver rib bookkeeping. r? `@petrochenkov`

Rollup merge of rust-lang#144634 - lucaswerkmeister:patch-1, r=lqd

7088bf5

Fix typo in `DropGuard` doc Follows-up rust-lang#144236 (I happened to see the typo yesterday but didn’t think it should delay the PR’s merge so I kept quiet, sorryyyyy).

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 Jul 29, 2025

bors added the merged-by-bors This PR was explicitly merged by bors. label Jul 29, 2025

bors merged commit ac0cb05 into rust-lang:master Jul 29, 2025
11 checks passed

rustbot added this to the 1.90.0 milestone Jul 29, 2025

rustbot added the perf-regression Performance regression. label Jul 29, 2025

Zalathar deleted the rollup-t1yo1jy branch July 29, 2025 22:55

rustbot added the perf-regression-triaged The performance regression has been triaged. label Aug 4, 2025

panstromek mentioned this pull request Aug 4, 2025

Rollup of 12 pull requests #144876

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Rollup of 6 pull requests #144637

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edited by rustbot

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Test differences

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Job duration changes

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rust-timer commented Jul 29, 2025

Overall result: ❌✅ regressions and improvements - please read the text below

Instruction count

Max RSS (memory usage)

Cycles

Binary size

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