remove multiple unhelpful `reason = "..."` values from `#[unstable(...)]` invocations #151228

cyrgani · 2026-01-16T21:06:35Z

The vast majority of #[unstable()] attributes already has no explicit reason specified. This PR removes the reason = "..." value for the following unhelpful or meaningless reasons:

"recently added"
"new API"
"recently redesigned"
"unstable"

An example of how the message looks with and without a reason:

fn main() {
    Vec::<()>::into_parts;
    Vec::<()>::const_make_global;
}

error[E0658]: use of unstable library feature `box_vec_non_null`: new API
 --> src/main.rs:2:5
  |
2 |     Vec::<()>::into_parts;
  |     ^^^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #130364 <https://github.com/rust-lang/rust/issues/130364> for more information
  = help: add `#![feature(box_vec_non_null)]` to the crate attributes to enable
  = note: this compiler was built on 2026-01-15; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature `const_heap`
 --> src/main.rs:3:5
  |
3 |     Vec::<()>::const_make_global;
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #79597 <https://github.com/rust-lang/rust/issues/79597> for more information
  = help: add `#![feature(const_heap)]` to the crate attributes to enable
  = note: this compiler was built on 2026-01-15; consider upgrading it if it is out of date

Most of the remaining reasons after this are something similar to "this is an implementation detail for XYZ" or "this is not public". If this PR is approved, I'll look into those next.

The PR also removes the fd_read feature gate. It only consists of one attribute applied to an implementation inside a module that is already private and unstable and should not be needed.

rustbot · 2026-01-16T21:06:40Z

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jhpratt · 2026-01-17T04:13:46Z

library/std/src/sys/net/connection/socket/windows.rs

    }
 }

-#[unstable(reason = "not public", issue = "none", feature = "fd_read")]


I had to dig into this one, as it wasn't immediately obvious. Nothing enables this feature and the struct is ultimately not publicly accessible thru anything, so I'm confident that the attribute can be removed without issue.

jhpratt · 2026-01-17T04:14:32Z

I would've sworn the reason was mandatory, but I guess that's not the case given passing CI.

While I think it would be best to have the true reason for everything, I agree that the status quo is effectively useless. I do think that "this is an implementation detail"-style messages should be left.

@bors r+ rollup

rust-bors · 2026-01-17T04:14:36Z

📌 Commit 035bcfa has been approved by jhpratt

It is now in the queue for this repository.

rust-bors · 2026-01-17T09:45:06Z

☀️ Test successful - CI
Approved by: jhpratt
Pushing 844f131 to main...

github-actions · 2026-01-17T09:48:05Z

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 defdb83 (parent) -> 844f131 (this PR)

Test differences

Show 2 test diffs

2 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 844f13103a64a898897174b19811b3bfb093dc53 --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: 5699.9s -> 7979.2s (+40.0%)
x86_64-rust-for-linux: 3223.7s -> 2506.3s (-22.3%)
dist-apple-various: 4150.6s -> 3345.6s (-19.4%)
x86_64-gnu-llvm-20-2: 6135.8s -> 4954.6s (-19.3%)
i686-gnu-2: 6057.6s -> 5093.6s (-15.9%)
x86_64-gnu-tools: 3756.6s -> 3159.9s (-15.9%)
armhf-gnu: 5456.0s -> 4626.4s (-15.2%)
pr-check-1: 2062.1s -> 1755.4s (-14.9%)
aarch64-gnu-llvm-20-2: 3181.4s -> 2717.8s (-14.6%)
tidy: 154.1s -> 176.1s (+14.3%)

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 · 2026-01-17T10:54:56Z

Finished benchmarking commit (844f131): 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)	0.2%	[0.2%, 0.2%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

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

Cycles

Results (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)	2.6%	[2.6%, 2.6%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 475.301s -> 472.032s (-0.69%)
Artifact size: 383.51 MiB -> 383.50 MiB (-0.00%)

…=scottmcm remove `#[deprecated]` from unstable & internal `SipHasher13` and `24` types These types are unstable and `doc(hidden)` (under the internal feature `hashmap_internals`). Deprecating them only adds noise (`#[allow(deprecated)]`) to all places where they are used, so this PR removes the deprecation attributes from them. It also includes a few other small cleanups in separate commits, including one I overlooked in rust-lang#151228.

Rollup merge of #151383 - cyrgani:no-internal-deprecation, r=scottmcm remove `#[deprecated]` from unstable & internal `SipHasher13` and `24` types These types are unstable and `doc(hidden)` (under the internal feature `hashmap_internals`). Deprecating them only adds noise (`#[allow(deprecated)]`) to all places where they are used, so this PR removes the deprecation attributes from them. It also includes a few other small cleanups in separate commits, including one I overlooked in #151228.

remove `#[deprecated]` from unstable & internal `SipHasher13` and `24` types These types are unstable and `doc(hidden)` (under the internal feature `hashmap_internals`). Deprecating them only adds noise (`#[allow(deprecated)]`) to all places where they are used, so this PR removes the deprecation attributes from them. It also includes a few other small cleanups in separate commits, including one I overlooked in rust-lang/rust#151228.

cyrgani added 5 commits January 16, 2026 13:31

delete weird fd_read feature

e45e4a7

remove reason = "recently added" from #[unstable(...)]

f13b154

remove reason = "new API" from #[unstable(...)]

69da401

remove reason = "recently redesigned" from #[unstable(...)]

8cb5da3

remove reason = "unstable" from #[unstable(...)]

035bcfa

rustbot assigned jhpratt Jan 16, 2026

rustbot added O-unix Operating system: Unix-like S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Jan 16, 2026

jhpratt reviewed Jan 17, 2026

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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 Jan 17, 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 Jan 17, 2026

rust-bors bot merged commit 844f131 into rust-lang:main Jan 17, 2026
12 checks passed

rustbot added this to the 1.94.0 milestone Jan 17, 2026

rust-bors bot mentioned this pull request Jan 17, 2026

add Iterator::dedup and friends #145733

Open

cyrgani deleted the less-feature branch January 17, 2026 09:59

cyrgani mentioned this pull request Jan 19, 2026

remove #[deprecated] from unstable & internal SipHasher13 and 24 types #151383

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remove multiple unhelpful `reason = "..."` values from `#[unstable(...)]` invocations #151228

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remove multiple unhelpful reason = "..." values from #[unstable(...)] invocations #151228

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Overall result: ❌ regressions - no action needed

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remove multiple unhelpful `reason = "..."` values from `#[unstable(...)]` invocations #151228

remove multiple unhelpful `reason = "..."` values from `#[unstable(...)]` invocations #151228