UnsafePinned: update get() docs and signature to allow shared mutation#142162

Merged

bors merged 2 commits intorust-lang:masterfrom

RalfJung:unsafe-pinned-get

Jun 9, 2025

Member

RalfJung commented Jun 7, 2025

Follow-up to #140638, making get consistent with the fact that there's an UnsafeCell inside this type now by returning *mut T instead of *const T.

Cc @rust-lang/libs-api
Tracking issue: #125735


          UnsafePinned: update get() docs and signature to allow shared mutation

bafe406

rustbot assigned workingjubilee

Collaborator

rustbot commented Jun 7, 2025

r? @workingjubilee

rustbot has assigned @workingjubilee.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

rustbot added S-waiting-on-review T-libs labels

This was referenced Jun 7, 2025

UnsafePinned: also include the effects of UnsafeCell #140638

Merged

Tracking Issue for RFC 3467: UnsafePinned #125735

Open

traviscross reviewed

View reviewed changes

library/core/src/pin/unsafe_pinned.rs Outdated

Comment on lines 91 to 94

+                  /// This can be cast to a pointer of any kind.
+                  /// Ensure that the access is unique (no active references, mutable or not)
+                  /// when casting to `&mut T`, and ensure that there are no mutations
+                  /// or mutable aliases going on when casting to `&T`.

Contributor

traviscross Jun 7, 2025

Nit. This would be better, I'd suggest, mechanically wrapped.

Member

workingjubilee Jun 7, 2025

I personally prefer semantic linebreaks, since the primary way this will be read is in the actual compiled documentation form and so the internal format of our docs is best-off organized around tracking history.

I don't usually quibble much over it though.

Member Author

RalfJung Jun 7, 2025

We use auto-wrapping almost everywhere, and semantic wrapping doesn't go well with out 100 column limit, so I think I'll re-wrap this.

traviscross reviewed

View reviewed changes

library/core/src/pin/unsafe_pinned.rs Outdated

Comment on lines 93 to 94

		/// when casting to `&mut T`, and ensure that there are no mutations
		/// or mutable aliases going on when casting to `&T`.

Contributor

traviscross Jun 7, 2025

I'd suggest wording here along the lines of "...ensure that there are no ongoing mutations or live mutable references when casting to &T."

Member Author

RalfJung Jun 7, 2025

FWIW this paragraph is copied verbatim from UnsafeCell::get. I was hoping we could just reuse it without spending a lot of time on editing.^^

traviscross reviewed

View reviewed changes

library/core/src/pin/unsafe_pinned.rs Outdated

Comment on lines 92 to 93

		/// Ensure that the access is unique (no active references, mutable or not)
		/// when casting to `&mut T`, and ensure that there are no mutations

Contributor

traviscross Jun 7, 2025 •

edited

Loading

Since the second half of this, about casting to &T, makes note about ensuring there are no ongoing foreign writes (i.e. even if no active references exist), perhaps the first half should as well, since I'd expect casting to &mut T to have this same precondition.

workingjubilee reviewed

View reviewed changes

library/core/src/pin/unsafe_pinned.rs Outdated

+                  /// when casting to `&mut T`, and ensure that there are no mutations
+                  /// or mutable aliases going on when casting to `&T`.
+                  ///
+                  /// All the usual caveats around mutation shared state apply, see [`UnsafeCell`].

Member

workingjubilee Jun 7, 2025

Suggested change

      
                /// All the usual caveats around mutation shared state apply, see [`UnsafeCell`].
          
                /// All the usual caveats around mutation of shared state apply, see [`UnsafeCell`].

library/core/src/pin/unsafe_pinned.rs Outdated

Comment on lines 91 to 94

+                  /// This can be cast to a pointer of any kind.
+                  /// Ensure that the access is unique (no active references, mutable or not)
+                  /// when casting to `&mut T`, and ensure that there are no mutations
+                  /// or mutable aliases going on when casting to `&T`.

Member

workingjubilee Jun 7, 2025

I wonder if we can apply the deduplicating technique of #141609 or if it's even worth it here? Probably not, it's just a few lines.


          centralize aliasing rules discussion in UnsafeCell docs

bd0a81e

Member Author

RalfJung commented Jun 7, 2025 •

edited

Loading

I've replaced the paragraph in question with a reference to the UnsafeCell docs, which already have a much better discussion of the aliasing rules.

traviscross approved these changes

View reviewed changes

Contributor

traviscross left a comment

Looks good to me.

Member Author

RalfJung commented Jun 8, 2025 via email

@bors r=traviscross

Collaborator

bors commented Jun 8, 2025

📌 Commit bd0a81e has been approved by traviscross

It is now in the queue for this repository.

bors added S-waiting-on-bors and removed S-waiting-on-review labels

workingjubilee added a commit to workingjubilee/rustc that referenced this pull request


          Rollup merge of rust-lang#142162 - RalfJung:unsafe-pinned-get, r=trav…

d534d3e

…iscross

UnsafePinned: update get() docs and signature to allow shared mutation

Follow-up to rust-lang#140638, making `get` consistent with the fact that there's an `UnsafeCell` inside this type now by returning `*mut T` instead of `*const T`.

Cc `@rust-lang/libs-api`
Tracking issue: rust-lang#125735

workingjubilee mentioned this pull request

Rollup of 11 pull requests #142195

Closed

bors added a commit that referenced this pull request


          Auto merge of #142195 - workingjubilee:rollup-yhkz9am, r=workingjubilee

c5445dc

Rollup of 11 pull requests

Successful merges:

 - #140774 (Affirm `-Cforce-frame-pointers=off` does not override)
 - #141001 (Make NonZero<char> possible)
 - #141700 (Atomic intrinsics : use const generic ordering, part 2)
 - #142008 (const-eval error: always say in which item the error occurred)
 - #142053 (Add new Tier-3 targets: `loongarch32-unknown-none*`)
 - #142089 (Replace all uses of sysroot_candidates with get_or_default_sysroot)
 - #142108 (compiler: Add track_caller to AbiMapping::unwrap)
 - #142132 (`tests/ui`: A New Order [6/N])
 - #142162 (UnsafePinned: update get() docs and signature to allow shared mutation)
 - #142171 (`tests/ui`: A New Order [7/N])
 - #142179 (store `target.min_global_align` as an `Align`)

r? `@ghost`
`@rustbot` modify labels: rollup

Member

workingjubilee commented Jun 8, 2025

?
@bors r-
@bors r=workingjubilee,traviscross

bors added S-waiting-on-author and removed S-waiting-on-bors labels

Collaborator

bors commented Jun 8, 2025

📌 Commit bd0a81e has been approved by workingjubilee,traviscross

It is now in the queue for this repository.

bors added S-waiting-on-bors and removed S-waiting-on-author labels

workingjubilee added a commit to workingjubilee/rustc that referenced this pull request


          Rollup merge of rust-lang#142162 - RalfJung:unsafe-pinned-get, r=work…

f82d81b

…ingjubilee,traviscross

UnsafePinned: update get() docs and signature to allow shared mutation

Follow-up to rust-lang#140638, making `get` consistent with the fact that there's an `UnsafeCell` inside this type now by returning `*mut T` instead of `*const T`.

Cc `@rust-lang/libs-api`
Tracking issue: rust-lang#125735

This was referenced Jun 8, 2025

Rollup of 13 pull requests #142213

Closed

Rollup of 12 pull requests #142220

Merged

bors added a commit that referenced this pull request


          Auto merge of #142220 - workingjubilee:rollup-idgfpof, r=workingjubilee

334ba81

Rollup of 12 pull requests

Successful merges:

 - #141803 (Remove rustc's notion of "preferred" alignment AKA `__alignof`)
 - #142053 (Add new Tier-3 targets: `loongarch32-unknown-none*`)
 - #142089 (Replace all uses of sysroot_candidates with get_or_default_sysroot)
 - #142108 (compiler: Add track_caller to AbiMapping::unwrap)
 - #142132 (`tests/ui`: A New Order [6/N])
 - #142162 (UnsafePinned: update get() docs and signature to allow shared mutation)
 - #142171 (`tests/ui`: A New Order [7/N])
 - #142179 (store `target.min_global_align` as an `Align`)
 - #142183 (Added test for 30904)
 - #142194 (Remove all unused feature gates from the compiler)
 - #142199 (Do not free disk space in the `mingw-check-tidy` job)
 - #142210 (Run `mingw-check-tidy` on auto builds)

r? `@ghost`
`@rustbot` modify labels: rollup

bors merged commit faab021 into rust-lang:master

10 checks passed

rustbot added this to the 1.89.0 milestone

rust-timer added a commit that referenced this pull request


          Unrolled build for #142162

46b495c

Rollup merge of #142162 - RalfJung:unsafe-pinned-get, r=workingjubilee,traviscross

UnsafePinned: update get() docs and signature to allow shared mutation

Follow-up to #140638, making `get` consistent with the fact that there's an `UnsafeCell` inside this type now by returning `*mut T` instead of `*const T`.

Cc ``@rust-lang/libs-api``
Tracking issue: #125735

RalfJung deleted the unsafe-pinned-get branch

June 9, 2025 09:03

github-actions bot pushed a commit to rust-lang/miri that referenced this pull request


          Auto merge of #142220 - workingjubilee:rollup-idgfpof, r=workingjubilee

9314af9

Rollup of 12 pull requests

Successful merges:

 - rust-lang/rust#141803 (Remove rustc's notion of "preferred" alignment AKA `__alignof`)
 - rust-lang/rust#142053 (Add new Tier-3 targets: `loongarch32-unknown-none*`)
 - rust-lang/rust#142089 (Replace all uses of sysroot_candidates with get_or_default_sysroot)
 - rust-lang/rust#142108 (compiler: Add track_caller to AbiMapping::unwrap)
 - rust-lang/rust#142132 (`tests/ui`: A New Order [6/N])
 - rust-lang/rust#142162 (UnsafePinned: update get() docs and signature to allow shared mutation)
 - rust-lang/rust#142171 (`tests/ui`: A New Order [7/N])
 - rust-lang/rust#142179 (store `target.min_global_align` as an `Align`)
 - rust-lang/rust#142183 (Added test for 30904)
 - rust-lang/rust#142194 (Remove all unused feature gates from the compiler)
 - rust-lang/rust#142199 (Do not free disk space in the `mingw-check-tidy` job)
 - rust-lang/rust#142210 (Run `mingw-check-tidy` on auto builds)

r? `@ghost`
`@rustbot` modify labels: rollup

tautschnig pushed a commit to model-checking/verify-rust-std that referenced this pull request


          Rollup merge of rust-lang#142162 - RalfJung:unsafe-pinned-get, r=work…

a672cc2

…ingjubilee,traviscross

UnsafePinned: update get() docs and signature to allow shared mutation

Follow-up to rust-lang#140638, making `get` consistent with the fact that there's an `UnsafeCell` inside this type now by returning `*mut T` instead of `*const T`.

Cc ``@rust-lang/libs-api``
Tracking issue: rust-lang#125735

RalfJung mentioned this pull request

UnsafePinned::raw_get: sync signature with get #145593

Merged

jhpratt added a commit to jhpratt/rust that referenced this pull request


          Rollup merge of rust-lang#145593 - RalfJung:unsafepinned-raw_get, r=M…

6c93b3a

…ark-Simulacrum

UnsafePinned::raw_get: sync signature with get

This was forgotten in rust-lang#142162.

Tracking issue: rust-lang#125735.

jhpratt added a commit to jhpratt/rust that referenced this pull request


          Rollup merge of rust-lang#145593 - RalfJung:unsafepinned-raw_get, r=M…

1d02056

…ark-Simulacrum

UnsafePinned::raw_get: sync signature with get

This was forgotten in rust-lang#142162.

Tracking issue: rust-lang#125735.

rust-timer added a commit that referenced this pull request


          Unrolled build for #145593

073acff

Rollup merge of #145593 - RalfJung:unsafepinned-raw_get, r=Mark-Simulacrum

UnsafePinned::raw_get: sync signature with get

This was forgotten in #142162.

Tracking issue: #125735.

github-actions bot pushed a commit to model-checking/verify-rust-std that referenced this pull request


          Rollup merge of rust-lang#145593 - RalfJung:unsafepinned-raw_get, r=M…

e51d7a5

…ark-Simulacrum

UnsafePinned::raw_get: sync signature with get

This was forgotten in rust-lang#142162.

Tracking issue: rust-lang#125735.

christian-schilling pushed a commit to christian-schilling/rustc_codegen_cranelift that referenced this pull request


          Auto merge of #142220 - workingjubilee:rollup-idgfpof, r=workingjubilee

5b31687

Rollup of 12 pull requests

Successful merges:

 - rust-lang/rust#141803 (Remove rustc's notion of "preferred" alignment AKA `__alignof`)
 - rust-lang/rust#142053 (Add new Tier-3 targets: `loongarch32-unknown-none*`)
 - rust-lang/rust#142089 (Replace all uses of sysroot_candidates with get_or_default_sysroot)
 - rust-lang/rust#142108 (compiler: Add track_caller to AbiMapping::unwrap)
 - rust-lang/rust#142132 (`tests/ui`: A New Order [6/N])
 - rust-lang/rust#142162 (UnsafePinned: update get() docs and signature to allow shared mutation)
 - rust-lang/rust#142171 (`tests/ui`: A New Order [7/N])
 - rust-lang/rust#142179 (store `target.min_global_align` as an `Align`)
 - rust-lang/rust#142183 (Added test for 30904)
 - rust-lang/rust#142194 (Remove all unused feature gates from the compiler)
 - rust-lang/rust#142199 (Do not free disk space in the `mingw-check-tidy` job)
 - rust-lang/rust#142210 (Run `mingw-check-tidy` on auto builds)

r? `@ghost`
`@rustbot` modify labels: rollup

christian-schilling pushed a commit to christian-schilling/rustc_codegen_cranelift that referenced this pull request


          Auto merge of #142220 - workingjubilee:rollup-idgfpof, r=workingjubilee

fea48d4

Rollup of 12 pull requests

Successful merges:

 - rust-lang/rust#141803 (Remove rustc's notion of "preferred" alignment AKA `__alignof`)
 - rust-lang/rust#142053 (Add new Tier-3 targets: `loongarch32-unknown-none*`)
 - rust-lang/rust#142089 (Replace all uses of sysroot_candidates with get_or_default_sysroot)
 - rust-lang/rust#142108 (compiler: Add track_caller to AbiMapping::unwrap)
 - rust-lang/rust#142132 (`tests/ui`: A New Order [6/N])
 - rust-lang/rust#142162 (UnsafePinned: update get() docs and signature to allow shared mutation)
 - rust-lang/rust#142171 (`tests/ui`: A New Order [7/N])
 - rust-lang/rust#142179 (store `target.min_global_align` as an `Align`)
 - rust-lang/rust#142183 (Added test for 30904)
 - rust-lang/rust#142194 (Remove all unused feature gates from the compiler)
 - rust-lang/rust#142199 (Do not free disk space in the `mingw-check-tidy` job)
 - rust-lang/rust#142210 (Run `mingw-check-tidy` on auto builds)

r? `@ghost`
`@rustbot` modify labels: rollup

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

S-waiting-on-bors T-libs