Rollup of 6 pull requests by JonathanBrouwer · Pull Request #157320 · rust-lang/rust

JonathanBrouwer · 2026-06-02T15:53:42Z

Successful merges:

transmute: fix check for whether newtypes have equal size #155418 (transmute: fix check for whether newtypes have equal size)
Clarify E0381 diagnostics for branch conditions #156603 (Clarify E0381 diagnostics for branch conditions)
Document run-make external dependencies #156643 (Document run-make external dependencies)
Avoid unreachable_code on required return values #157009 (Avoid unreachable_code on required return values)
make typing mode exhaustive again... #157308 (make typing mode exhaustive again...)
disallow most attrs on eiis #157312 (disallow most attrs on eiis)

…omatsakis transmute: fix check for whether newtypes have equal size The `transmute` check has some logic to be able to tell whether two types that involve generics will always have the same size. That logic has a bug: it ignores the fact that `repr(align)` can affect the size of a type. This PR fixes that bug by making the check bail out for most `repr` flags. That rejects some previously accepted code, hence the @rust-lang/lang nomination. The new logic says that a type is a transparent newtype wrapper around a pointer for `transmute` purposes only if - It is a struct without any `repr` flags except for `repr(transparent)` and `repr(C)`. - It is a single-variant enum without any `repr` flags except for `repr(transparent)`. - Or it is a two-variant enum without any `repr` flags except for `repr(transparent)` that matches the NPO rules. The inner type must be `non_zero: true` (which holds for references and `NonNull`), and the wrapper type is then marked as `non_zero: false`. Fixes rust-lang#155412 Fixes rust-lang#88290 I manually checked that the playground example linked in rust-lang#88290 now emits all three expected errors (and we have equivalent cases in the tests, either preexisting or added by this PR, so it didn't seem worth adding that example as well).

…on-note, r=nikomatsakis Clarify E0381 diagnostics for branch conditions this pr want to fix: rust-lang#156494

…nal-deps, r=nikomatsakis Document run-make external dependencies Part of rust-lang#125585. This documents the common external tool helpers available to run-make recipes and the environment variables that compiletest uses to provide those tools. It also points tests that require optional tools or LLVM components toward the relevant compiletest directives. Validation: - `./x test tidy`

…r=cjgillot Avoid `unreachable_code` on required return values This PR skips return-place assignment plumbing when selecting user code to lint after an uninhabited call. Fixes rust-lang#152559 r? cjgillot

@oli-obk

make typing mode exhaustive again... r? @oli-obk See rust-lang#155443 (comment)

@JonathanBrouwer

…onathanBrouwer disallow most attrs on eiis Most attributes do not make sense on EIIs. Whether they're copied to the macro, default, or foreign item is also highly dependent per attribute. I was thinking of ways to configure this, though I don't think we need that kind of complexity rn. For now I just reject them all, except for ones that obviously make sense or are necessary for current usage in std. user attr macros are blanket-rejected with this too, which seems good, it seems cursed to present expanded eiis to them. r? @JonathanBrouwer

JonathanBrouwer · 2026-06-02T15:53:59Z

@bors r+ rollup=never p=5

rust-bors · 2026-06-02T15:54:08Z

📌 Commit 14cf0b6 has been approved by JonathanBrouwer

It is now in the queue for this repository.

…uwer Rollup of 6 pull requests Successful merges: - #155418 (transmute: fix check for whether newtypes have equal size) - #156603 (Clarify E0381 diagnostics for branch conditions) - #156643 (Document run-make external dependencies) - #157009 (Avoid `unreachable_code` on required return values) - #157308 (make typing mode exhaustive again...) - #157312 (disallow most attrs on eiis)

rust-bors · 2026-06-02T16:05:01Z

💔 Test for f21b86e failed: CI. Failed job:

auto - pr-check-1 (web logs, enhanced plaintext logs)

JonathanBrouwer · 2026-06-02T16:07:48Z

@bors retry

rust-log-analyzer · 2026-06-02T16:13:12Z

A job failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

rust-bors · 2026-06-02T19:23:19Z

☀️ Test successful - CI
Approved by: JonathanBrouwer
Duration: 3h 15m 4s
Pushing 20e19ee to main...

rust-timer · 2026-06-02T19:25:09Z

📌 Perf builds for each rolled up PR:

PR#	Message	Perf Build Sha
#155418	transmute: fix check for whether newtypes have equal size	`e9cc217870086f11c7fc2acd413e1c36faac7d2b` (link)
#156603	Clarify E0381 diagnostics for branch conditions	`7104ea7125838862dc9f5a0b4c515af0d6c804b6` (link)
#156643	Document run-make external dependencies	`86d0eb8b6ef95c5ce339d8ec72923f75670065ee` (link)
#157009	Avoid `unreachable_code` on required return values	`80a239921e7cfe7911fdf2e25b8f7cbe6fa1c779` (link)
#157308	make typing mode exhaustive again...	`c0757f83c7fc4d083815b7f0421100b8b50bd80b` (link)
#157312	disallow most attrs on eiis	`65460c22c23969c67c708e3801fd1d5420ac1400` (link)

previous master: 48f976c713

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 · 2026-06-02T19:26:36Z

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 48f976c (parent) -> 20e19ee (this PR)

Test differences

Show 34 test diffs

Stage 1

[ui] tests/ui/borrowck/branch-condition-flow-issue-156494.rs: [missing] -> pass (J1)
[ui] tests/ui/eii/attrs.rs: [missing] -> pass (J1)
[ui] tests/ui/eii/ice_contract_attr_on_eii_generated_item.rs: pass -> [missing] (J1)
[ui] tests/ui/transmute/raw-ptr-non-null.rs: pass -> [missing] (J1)

Stage 2

[ui] tests/ui/borrowck/branch-condition-flow-issue-156494.rs: [missing] -> pass (J0)
[ui] tests/ui/eii/attrs.rs: [missing] -> pass (J0)
[ui] tests/ui/eii/ice_contract_attr_on_eii_generated_item.rs: pass -> [missing] (J0)
[ui] tests/ui/transmute/raw-ptr-non-null.rs: pass -> [missing] (J0)

Additionally, 26 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 20e19eeac0c548e31f84d3914e0ce17cde618119 --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: 7m 55s -> 14m 24s (+81.7%)
dist-i686-msvc: 1h 25m -> 2h 24m (+69.5%)
dist-x86_64-freebsd: 1h 3m -> 1h 31m (+44.4%)
i686-gnu-nopt-1: 1h 39m -> 2h 23m (+43.6%)
x86_64-gnu-llvm-22-3: 1h 28m -> 1h 59m (+34.9%)
x86_64-gnu-llvm-21-2: 1h 14m -> 1h 39m (+32.8%)
dist-x86_64-msvc-alt: 2h 10m -> 2h 50m (+30.0%)
x86_64-msvc-ext2: 1h 27m -> 1h 49m (+25.2%)
dist-aarch64-apple: 1h 31m -> 1h 52m (+23.7%)
dist-x86_64-mingw: 2h -> 2h 28m (+22.9%)

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 · 2026-06-02T20:05:37Z

Finished benchmarking commit (20e19ee): comparison URL.

Overall result: ❌✅ regressions and improvements - 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)	0.4%	[0.1%, 1.1%]	4
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.2%	[-0.3%, -0.0%]	8
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 2.3%, secondary 0.4%)

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

	mean	range	count
Regressions ❌ (primary)	7.1%	[7.1%, 7.1%]	1
Regressions ❌ (secondary)	2.0%	[1.4%, 2.8%]	4
Improvements ✅ (primary)	-2.6%	[-2.6%, -2.6%]	1
Improvements ✅ (secondary)	-2.7%	[-3.2%, -2.3%]	2
All ❌✅ (primary)	2.3%	[-2.6%, 7.1%]	2

Cycles

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)	2.4%	[2.4%, 2.4%]	1
Regressions ❌ (secondary)	4.8%	[2.3%, 8.8%]	3
Improvements ✅ (primary)	-2.3%	[-2.3%, -2.3%]	1
Improvements ✅ (secondary)	-3.1%	[-4.3%, -2.0%]	4
All ❌✅ (primary)	0.1%	[-2.3%, 2.4%]	2

Binary size

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

Bootstrap: 510.698s -> 511.673s (0.19%)
Artifact size: 400.57 MiB -> 400.63 MiB (0.02%)

RalfJung and others added 14 commits May 8, 2026 10:10

transmute: fix check for whether newtypes have equal size

4a09f12

Clarify E0381 diagnostics for branch conditions

cb680f9

Document run-make external dependencies

022b301

add red test

b63b839

avoid unreachable_code on required return values

7451f1d

make typing mode exhaustive again...

08832da

disallow most attrs on eiis

1251494

add test for attrs on eiis

a492d4f

Rollup merge of rust-lang#156603 - eval-exec:e0381-diagnostic-conditi…

b1e7469

…on-note, r=nikomatsakis Clarify E0381 diagnostics for branch conditions this pr want to fix: rust-lang#156494

Rollup merge of rust-lang#157009 - qaijuang:unreachable-return-tail, …

9d2e3ff

…r=cjgillot Avoid `unreachable_code` on required return values This PR skips return-place assignment plumbing when selecting user code to lint after an uninhabited call. Fixes rust-lang#152559 r? cjgillot

Rollup merge of rust-lang#157308 - jdonszelmann:tm-exhaustive, r=oli-obk

ab13031

make typing mode exhaustive again... r? @oli-obk See rust-lang#155443 (comment)

rust-bors Bot added the rollup A PR which is a rollup label Jun 2, 2026

rustbot added A-run-make Area: port run-make Makefiles to rmake.rs 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 Jun 2, 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 Jun 2, 2026

This comment has been minimized.

Sign in to view

rust-bors Bot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Jun 2, 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 Jun 2, 2026

This comment has been minimized.

Sign in to view

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 Jun 2, 2026

rust-bors Bot merged commit 20e19ee into rust-lang:main Jun 2, 2026
13 checks passed

rustbot added this to the 1.98.0 milestone Jun 2, 2026

This was referenced Jun 2, 2026

Support defaults for static EIIs #156583

Open

Reject #[no_mangle]/#[link_name]/#[export_name] on EII #156871

Open

rustbot added the perf-regression Performance regression. label Jun 2, 2026

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Rollup of 6 pull requests#157320

Rollup of 6 pull requests#157320
rust-bors[bot] merged 14 commits into
rust-lang:mainfrom
JonathanBrouwer:rollup-ECUZfbo

JonathanBrouwer commented Jun 2, 2026

Uh oh!

JonathanBrouwer commented Jun 2, 2026

Uh oh!

rust-bors Bot commented Jun 2, 2026

Uh oh!

This comment has been minimized.

rust-bors Bot commented Jun 2, 2026

Uh oh!

JonathanBrouwer commented Jun 2, 2026

Uh oh!

This comment has been minimized.

rust-log-analyzer commented Jun 2, 2026

Uh oh!

rust-bors Bot commented Jun 2, 2026

Uh oh!

Uh oh!

rust-timer commented Jun 2, 2026

Uh oh!

github-actions Bot commented Jun 2, 2026

Stage 1

Stage 2

Uh oh!

rust-timer commented Jun 2, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

9 participants

Uh oh!

Conversation

JonathanBrouwer commented Jun 2, 2026

Uh oh!

JonathanBrouwer commented Jun 2, 2026

Uh oh!

rust-bors Bot commented Jun 2, 2026

Uh oh!

This comment has been minimized.

rust-bors Bot commented Jun 2, 2026

Uh oh!

JonathanBrouwer commented Jun 2, 2026

Uh oh!

This comment has been minimized.

rust-log-analyzer commented Jun 2, 2026

Uh oh!

rust-bors Bot commented Jun 2, 2026

Uh oh!

Uh oh!

rust-timer commented Jun 2, 2026

Uh oh!

github-actions Bot commented Jun 2, 2026

Test differences

Stage 1

Stage 2

Job duration changes

Uh oh!

rust-timer commented Jun 2, 2026

Overall result: ❌✅ regressions and improvements - please read:

Instruction count

Max RSS (memory usage)

Cycles

Binary size

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

9 participants