Migrate libraries from ptr::slice_from_raw_parts to .cast_slice by Paladynee · Pull Request #156109 · rust-lang/rust

Paladynee · 2026-05-03T12:41:14Z

Tracking issue for #![feature(ptr_cast_slice)]: #149103
This commit updates most callsites of ptr::slice_from_raw_parts within ./library to the more concise but unstable postfix .cast_slice() method on raw pointers, using the ptr_cast_slice feature. Some tests in alloctests have also been updated.

No functional change, debatably improved readability.

rustbot · 2026-05-03T12:41:16Z

stdarch is developed in its own repository. If possible, consider making this change to rust-lang/stdarch instead.

cc @Amanieu, @folkertdev, @sayantn

rustbot · 2026-05-03T12:41:18Z

r? @jhpratt

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Paladynee · 2026-05-03T12:56:17Z

some notable places like core::slice::from_raw_parts have not been updated, because i felt like changing that would harm readability than improving it.

Paladynee · 2026-05-03T13:26:24Z

hmm wait let me revert that doc change, apparently it is exactly the same in std::ptr::slice_from_raw_parts. this is all so confusing since all the names are super similar lol

xtqqczze · 2026-05-03T22:46:15Z

Could &*ptr::slice_from_raw_parts be written as slice::from_raw_parts?

jhpratt · 2026-05-04T05:08:40Z

stdarch is developed in its own repository. If possible, consider making this change to rust-lang/stdarch instead.

Aside from this, r=me

jhpratt · 2026-05-04T05:08:44Z

@rustbot author

rustbot · 2026-05-04T05:08:49Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

Paladynee · 2026-05-04T17:22:20Z

Could &*ptr::slice_from_raw_parts be written as slice::from_raw_parts?

i believe they are equivalent other than the debug UB assertion, yes

Paladynee · 2026-05-04T17:28:40Z

I'm not touching anything in;

coretests
core::slice
any ptr::slice_from_raw_parts{_mut} call in stable documentations
believe i can revert the stdarch thing since it seems too complicated for me to change for now

with that, i think this pr is ready

@rustbot ready

xtqqczze · 2026-05-05T14:39:54Z

Could &*ptr::slice_from_raw_parts be written as slice::from_raw_parts?

The library/core/src/slice/sort/shared/smallsort.rs changes should be reverted as they conflict with #156192.

Paladynee · 2026-05-06T01:47:34Z

Could &*ptr::slice_from_raw_parts be written as slice::from_raw_parts?

The library/core/src/slice/sort/shared/smallsort.rs changes should be reverted as they conflict with #156192.

done

jhpratt · 2026-05-07T01:54:51Z

@bors r+ rollup

rust-bors · 2026-05-07T01:54:53Z

📌 Commit 14315f9 has been approved by jhpratt

It is now in the queue for this repository.

…nts, r=jhpratt Migrate libraries from ptr::slice_from_raw_parts to .cast_slice Tracking issue for `#![feature(ptr_cast_slice)]`: rust-lang#149103 This commit updates most callsites of ptr::slice_from_raw_parts within ./library to the more concise but unstable postfix `.cast_slice()` method on raw pointers, using the `ptr_cast_slice` feature. Some tests in alloctests have also been updated. No functional change, debatably improved readability.

Rollup of 14 pull requests Successful merges: - #146273 (lint ImproperCTypes: refactor linting architecture (part 2)) - #149509 (Lint unused pub items in binary crates) - #156173 (Fewer global node_id_to_def_id lookups) - #156177 (windows/time: avoid being too close to 0) - #155961 (Deny warnings in the test for crates that are available on stable) - #155981 (Use special DefIds for aliases) - #156109 (Migrate libraries from ptr::slice_from_raw_parts to .cast_slice) - #156130 (Fold/visit tweaks) - #156131 (Metadata macro/query cleanups) - #156202 (llvm: Use correct type for splat mask) - #156227 (Add Trusty OS to the generic error implementation.) - #156237 (compiletest: prevent directives from having multiple revisions) - #156241 (Move tests coercion) - #156258 (Document wasi-sdk minimum versions for WASI targets)

jhpratt · 2026-05-07T06:11:39Z

@bors r-

#156263 (comment)

rust-bors · 2026-05-07T06:11:47Z

This pull request was unapproved.

This PR was contained in a rollup (#156263), which was unapproved.

View changes since this unapproval

xtqqczze · 2026-05-07T12:14:36Z

        assert_eq!(size % elem_size, 0);
        let len = size / elem_size;
-        ptr::slice_from_raw_parts_mut(ptr as _, len)
+        (ptr as _).cast_slice(len)


error[E0282]: type annotations needed --> /rustc/620725bffcba2613fa6243f559657c2bedb5615f/library/std/src/sys/pal/sgx/abi/usercalls/alloc.rs:154:9 | 154 | (ptr as _).cast_slice(len) | ^^^^^^^^^^ cannot infer type

https://github.com/rust-lang/rust/actions/runs/25475505562/job/74748095499#step:28:10939

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rustbot added O-SGX Target: SGX 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 May 3, 2026

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Paladynee force-pushed the lib/cast-slice-improvements branch 3 times, most recently from 5533d7b to fced58f Compare May 3, 2026 15:10

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels May 4, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels May 4, 2026

Paladynee force-pushed the lib/cast-slice-improvements branch from fced58f to e030a3f Compare May 4, 2026 17:33

Migrate libraries from ptr::slice_from_raw_parts to .cast_slice

14315f9

Paladynee force-pushed the lib/cast-slice-improvements branch from e030a3f to 14315f9 Compare May 6, 2026 01:47

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 May 7, 2026

jhpratt mentioned this pull request May 7, 2026

Rollup of 14 pull requests #156263

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rust-bors Bot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels May 7, 2026

xtqqczze reviewed May 7, 2026

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