Enforce safety comments on `alloc` by nia-e · Pull Request #160941 · rust-lang/rust

nia-e · 2026-08-11T20:28:01Z

cc @clarfonthey, @workingjubilee. Following up from #160824. I spent a painfully long time going over the comments and ensuring there's nothing too awful ^^

r? clarfonthey

nia-e · 2026-08-11T20:32:29Z

This will break a lot of ppl's CI ^^

@bors rollup=never

JonathanBrouwer · 2026-08-11T20:41:58Z

I'm not convinced rollup=never actually helps. This kind of PR is likely to have soft conflicts (i.e. someone adds an unsafe block between this PR being opened and merged), but rollup=never doesn't help detecting those. In fact, it makes them worse because soft conflicts may get detected in PR CI/try jobs of rollups and not waste queue time. My primary recommendation to help with this would be to reduce the time between PR open and r+, and rebase before r+ if this is more than a few days

JonathanBrouwer · 2026-08-11T20:43:39Z

@bors rollup=iffy p=1 likely to soft conflict
p=1 does help because it makes you get into rollups earlier reducing time between pr open & merge

nia-e · 2026-08-12T16:59:02Z

...i completely forgot to actually push the commit with all my manual work. apologies 🫠

clarfonthey · 2026-08-12T17:22:24Z

Oh, I didn't know that you were actually going through and adding comments to these. I'd, probably want to do an actual review in that case.

clarfonthey · 2026-08-12T17:39:14Z

 type Cap = core::num::niche_types::UsizeNoHighBit;

-// SAFETY: Untriaged.
+// SAFETY: 0 *definitely* is less than isize::MAX.


But how can you be sure?

View changes since the review

easy: isize was defined before 2025 and therefore there were affordable computers around that had to address more than 0 bytes of memory!

clarfonthey · 2026-08-29T13:18:05Z

Okay, that was painful, but reviewed.

@bors try

Enforce safety comments on `alloc`

clarfonthey · 2026-08-29T13:21:00Z

Recommended merge command assuming try passes:

r=clarfonthey p=1 note="Affects entire alloc crate, can easily go stale"

clarfonthey · 2026-08-29T13:22:24Z

Also fine with you just rebasing this yourself and merging in case of conflicts, assuming you mark new blocks as ignored instead of trying to determine what their comments should be.

rust-bors · 2026-08-29T14:19:12Z

☀️ Try build successful (CI)
Build commit: 8e834e4 (8e834e4af0546ff9e43f5ddca26d6ea6c9305778)
Base parent: 6bb812b (6bb812b714cce8e08864b7b569303f25ab08eaad)

clarfonthey · 2026-08-29T15:54:01Z

@bors r+ p=1 note="Affects entire alloc crate, can easily go stale"

rust-bors · 2026-08-29T15:54:04Z

📌 Commit 483873e has been approved by clarfonthey

It is now in the queue for this repository.

@clarfonthey

…rfonthey Enforce safety comments on `alloc` cc @clarfonthey, @workingjubilee. Following up from rust-lang#160824. I spent a painfully long time going over the comments and ensuring there's nothing too awful ^^ r? clarfonthey

@clarfonthey

…rfonthey Enforce safety comments on `alloc` cc @clarfonthey, @workingjubilee. Following up from rust-lang#160824. I spent a painfully long time going over the comments and ensuring there's nothing too awful ^^ r? clarfonthey

Rollup of 7 pull requests Successful merges: - #160941 (Enforce safety comments on `alloc`) - #161975 (Abort instead of unwinding out of an inconsistent BTreeMap::split_off) - #157968 (Preserve ambiguous glob lint for subtrait method picks) - #161514 (rework handling of doc attributes on macro calls) - #161944 (rustdoc: Take into account edition information for keyword highlighting) - #161974 (remove rustc_never_type_options attr remnants) - #161978 (Move rustdoc ui doctests into the right testsuite) Failed merges: - #161702 (Use `drop_guard` in some places in {core,alloc,std})

@clarfonthey

Rollup merge of #160941 - nia-e:alloc-safety-comments, r=clarfonthey Enforce safety comments on `alloc` cc @clarfonthey, @workingjubilee. Following up from #160824. I spent a painfully long time going over the comments and ensuring there's nothing too awful ^^ r? clarfonthey

…, r=Darksonn alloc: a bunch of safety comments Following up from rust-lang#160941. Triaging this is what found the errors in rust-lang#162285 & rust-lang#162286. More to come, but I didn't want to make the review effort too high on any single PR. r? libs

Rollup merge of #162289 - nia-e:alloc-safety-comments-part-2, r=Darksonn alloc: a bunch of safety comments Following up from #160941. Triaging this is what found the errors in #162285 & #162286. More to come, but I didn't want to make the review effort too high on any single PR. r? libs

rustbot assigned clarfonthey Aug 11, 2026