Rollup of 4 pull requests by JonathanBrouwer · Pull Request #150559 · rust-lang/rust

JonathanBrouwer · 2026-01-01T01:47:22Z

Successful merges:

crate::io::Result → io::Result in most places #149778 (crate::io::Result → io::Result in most places)
split up tracking issue for target feature feature gates #150264 (split up tracking issue for target feature feature gates)
region_scope_tree: Rewrite a loop as tail recursion #150548 (region_scope_tree: Rewrite a loop as tail recursion)
Enable thumb interworking on ARMv7A/R and ARMv8R bare-metal targets #150555 (Enable thumb interworking on ARMv7A/R and ARMv8R bare-metal targets)

r? @ghost
@rustbot modify labels: rollup

I don't know why many places refer to the type as `crate::io::Result` when `crate::io` is already imported.

…mulacrum `crate::io::Result` → `io::Result` in most places I don't know why many places refer to the type as `crate::io::Result` when `crate::io` is already imported.

…plit, r=Amanieu split up tracking issue for target feature feature gates rust-lang#44839 is tracking too many things at once. We usually have a separate tracking issue for each feature gate, so let's do that here as well: - rust-lang#150244 - rust-lang#150245 - rust-lang#150246 - rust-lang#150247 - rust-lang#150248 - rust-lang#150249 - rust-lang#150250 - rust-lang#150251 - rust-lang#150252 - rust-lang#150253 - rust-lang#150254 - rust-lang#150255 - rust-lang#150256 - rust-lang#150257 - rust-lang#150258 - rust-lang#150259 - rust-lang#150260 - rust-lang#150261 Closes rust-lang#44839 in favor of the ones listed above. r? `@Amanieu`

…ewrite, r=BoxyUwU `region_scope_tree`: Rewrite a `loop` as tail recursion This addresses rust-lang#146098 (comment), hopefully making `record_subexpr_extended_temp_scopes` a bit more legible. I removed a `debug!` in the process, since the function it calls every iteration, [`ScopeTree::record_extended_temp_scope`](https://github.com/rust-lang/rust/blob/2848c2ebe9a8a604cd63455263299d7258bc8252/compiler/rustc_middle/src/middle/region.rs#L264-L271), does the same `debug!`. Keeping the behavior of having an additional `debug!` for the top-level expression would hurt legibility, and having a duplicate `debug!` at each iteration seems excessive. No information is lost from the debug output, so I think it's fine to just have the inner `debug!`s. r? BoxyUwU or anyone

…=chenyukang Enable thumb interworking on ARMv7A/R and ARMv8R bare-metal targets This flag enables the `#[instruction_set(arm::t32)]` for the armv7a/armv7r/armv8r targets, which all support Thumb interwork but were missing this flag. Target maintainers are `@chrisnc,` `@rust-lang/arm-maintainers,` `@rust-embedded/arm` (including me).

JonathanBrouwer · 2026-01-01T01:47:33Z

@bors r+ rollup=never p=5

bors · 2026-01-01T01:47:36Z

📌 Commit 767e7da has been approved by JonathanBrouwer

It is now in the queue for this repository.

bors · 2026-01-01T04:32:58Z

⌛ Testing commit 767e7da with merge 6e48b44...

bors · 2026-01-01T07:51:26Z

☀️ Test successful - checks-actions
Approved by: JonathanBrouwer
Pushing 6e48b44 to main...

rust-timer · 2026-01-01T07:52:37Z

📌 Perf builds for each rolled up PR:

PR#	Message	Perf Build Sha
#149778	`crate::io::Result` → `io::Result` in most places	`813cbf4b89736082babb86efcbe6ca73fbd952b1` (link)
#150264	split up tracking issue for target feature feature gates	`360aa6a13c5c5f2f18c4ddd7a9f2c66234261fa9` (link)
#150548	`region_scope_tree`: Rewrite a `loop` as tail recursion	`8d94899201fecc4c3073b6825d8b8113c6447b72` (link)
#150555	Enable thumb interworking on ARMv7A/R and ARMv8R bare-metal…	`0e92c54e18364a3c0796430749f6f9506ddcb353` (link)

previous master: 4c62aa4468

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 · 2026-01-01T07:54:51Z

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 4c62aa4 (parent) -> 6e48b44 (this PR)

Test differences

Show 36 test diffs

36 doctest diffs were found. These are ignored, as they are noisy.

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 6e48b44e77d117d84ff3c340368dea3064117559 --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-aarch64-apple: 7662.7s -> 9357.3s (+22.1%)
dist-apple-various: 5438.9s -> 4265.6s (-21.6%)
aarch64-msvc-1: 7891.1s -> 6995.5s (-11.3%)
dist-aarch64-llvm-mingw: 5488.9s -> 6098.1s (+11.1%)
arm-android: 5858.6s -> 6490.2s (+10.8%)
dist-x86_64-netbsd: 5316.6s -> 4770.1s (-10.3%)
dist-ohos-aarch64: 4532.2s -> 4071.8s (-10.2%)
dist-ohos-x86_64: 4611.4s -> 4170.0s (-9.6%)
dist-x86_64-apple: 6895.1s -> 7531.4s (+9.2%)
x86_64-msvc-1: 9179.2s -> 8374.2s (-8.8%)

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 · 2026-01-01T08:33:05Z

Finished benchmarking commit (6e48b44): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -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)	0.1%	[0.1%, 0.2%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 2.5%, secondary -3.5%)

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

	mean	range	count
Regressions ❌ (primary)	2.5%	[2.5%, 2.5%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.5%	[-6.1%, -0.9%]	3
All ❌✅ (primary)	2.5%	[2.5%, 2.5%]	1

Cycles

Results (primary 9.2%, secondary 16.3%)

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

	mean	range	count
Regressions ❌ (primary)	9.2%	[3.1%, 15.1%]	10
Regressions ❌ (secondary)	18.0%	[2.8%, 29.6%]	11
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.3%	[-2.3%, -2.3%]	1
All ❌✅ (primary)	9.2%	[3.1%, 15.1%]	10

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 476.46s -> 476.234s (-0.05%)
Artifact size: 390.83 MiB -> 390.86 MiB (0.01%)

RalfJung and others added 8 commits December 22, 2025 13:29

split up tracking issue for target feature feature gates

a8e5693

crate::io::Result → io::Result in most places

440bf4d

I don't know why many places refer to the type as `crate::io::Result` when `crate::io` is already imported.

Enable thumb interworking on ARMv7A/R and ARMv8R bare-metal targets

59a3ad3

Rewrite a loop as tail recursion

6b60e81

Rollup merge of rust-lang#149778 - tbu-:pr_crate_io_result, r=Mark-Si…

9b89b88

…mulacrum `crate::io::Result` → `io::Result` in most places I don't know why many places refer to the type as `crate::io::Result` when `crate::io` is already imported.

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 Jan 1, 2026

bors added the merged-by-bors This PR was explicitly merged by bors. label Jan 1, 2026

bors merged commit 6e48b44 into rust-lang:main Jan 1, 2026
12 checks passed

rustbot added this to the 1.94.0 milestone Jan 1, 2026

bors mentioned this pull request Jan 1, 2026

Support using const pointers in asm const operand #138618

Open

This was referenced Jan 1, 2026

Temporary lifetime extension for blocks #146098

Open

Documented thread hooks on panics and errors of thread spawning functions. #149927

Open

Add Tier 3 Thumb-mode targets for Armv7-A, Armv7-R and Armv8-R #150556

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Rollup of 4 pull requests#150559

Rollup of 4 pull requests#150559
bors merged 8 commits intorust-lang:mainfrom
JonathanBrouwer:rollup-59hbbmm

JonathanBrouwer commented Jan 1, 2026 •

edited by rustbot

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Test differences

Job duration changes

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rust-timer commented Jan 1, 2026

Overall result: ❌ regressions - no action needed

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JonathanBrouwer commented Jan 1, 2026 •

edited by rustbot

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