Tracking Issue for `#![feature(const_cell_into_inner)]` #78729

a1phyr · 2020-11-04T10:56:03Z

This is a tracking issue for #![feature(const_cell_into_inner)].

Constantified functions are:

UnsafeCell::into_inner
Cell::into_inner
RefCell::into_inner
OnceCell::into_inner
~~Atomic*::into_inner~~ (done)

Steps

Implementation (Constantify UnsafeCell::into_inner and related #78728, Add const_cell_into_inner to OnceCell #129382)
FCP
Stabilization PR (Stabilize const_cell_into_inner. #84087)
Stabilize const Atomic*::into_inner #123522

The text was updated successfully, but these errors were encountered:

…lnay Constantify `UnsafeCell::into_inner` and related Tracking issue: rust-lang#78729 This PR constantifies: - `UnsafeCell::into_inner` - `Cell::into_inner` - `RefCell::into_inner` - `Atomic*::into_inner` r? `@dtolnay`

…lnay Constantify `UnsafeCell::into_inner` and related Tracking issue: rust-lang#78729 This PR constantifies: - `UnsafeCell::into_inner` - `Cell::into_inner` - `RefCell::into_inner` - `Atomic*::into_inner` r? ``@dtolnay``

…lnay Constantify `UnsafeCell::into_inner` and related Tracking issue: rust-lang#78729 This PR constantifies: - `UnsafeCell::into_inner` - `Cell::into_inner` - `RefCell::into_inner` - `Atomic*::into_inner` r? ```@dtolnay```

…lnay Constantify `UnsafeCell::into_inner` and related Tracking issue: rust-lang#78729 This PR constantifies: - `UnsafeCell::into_inner` - `Cell::into_inner` - `RefCell::into_inner` - `Atomic*::into_inner` r? ````@dtolnay````

…lnay Constantify `UnsafeCell::into_inner` and related Tracking issue: rust-lang#78729 This PR constantifies: - `UnsafeCell::into_inner` - `Cell::into_inner` - `RefCell::into_inner` - `Atomic*::into_inner` r? `````@dtolnay`````

m-ou-se · 2021-03-31T19:59:49Z

@rfcbot merge

cc @rust-lang/wg-const-eval

rfcbot · 2021-03-31T19:59:50Z

Team member @m-ou-se has proposed to merge this. The next step is review by the rest of the tagged team members:

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

rfcbot · 2021-03-31T20:57:02Z

🔔 This is now entering its final comment period, as per the review above. 🔔

rfcbot · 2021-04-10T20:58:28Z

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

The RFC will be merged soon.

dtolnay · 2024-04-05T23:08:59Z

According to #84087 (comment), this is blocked on the "precise drop analysis" unstable const feature (#73255).

…lstrieb Stabilize const Atomic*::into_inner Partial stabilization for rust-lang#78729, for which the FCP has already completed. The other `into_inner` functions in that tracking issue (`UnsafeCell`, `Cell`, `RefCell`) are blocked on rust-lang#73255 for now. ```console error[E0493]: destructor of `UnsafeCell<T>` cannot be evaluated at compile-time --> library/core/src/cell.rs:2076:29 | 2076 | pub const fn into_inner(self) -> T { | ^^^^ the destructor for this type cannot be evaluated in constant functions 2077 | self.value 2078 | } | - value is dropped here ```

Rollup merge of rust-lang#123522 - dtolnay:constatomicintoinner, r=Nilstrieb Stabilize const Atomic*::into_inner Partial stabilization for rust-lang#78729, for which the FCP has already completed. The other `into_inner` functions in that tracking issue (`UnsafeCell`, `Cell`, `RefCell`) are blocked on rust-lang#73255 for now. ```console error[E0493]: destructor of `UnsafeCell<T>` cannot be evaluated at compile-time --> library/core/src/cell.rs:2076:29 | 2076 | pub const fn into_inner(self) -> T { | ^^^^ the destructor for this type cannot be evaluated in constant functions 2077 | self.value 2078 | } | - value is dropped here ```

`Cell` and `RefCell` have their `into_inner` methods const unstable. `OnceCell` has the same logic, so add it under the same gate. Tracking issue: rust-lang#78729

tgross35 · 2024-08-22T01:37:16Z

Since this is still blocked, I made OnceCell::into_inner const under the same gate in #129382.

…r, r=Noratrieb Add `const_cell_into_inner` to `OnceCell` `Cell` and `RefCell` have their `into_inner` methods const unstable. `OnceCell` has the same logic, so add it under the same gate. Tracking issue: rust-lang#78729

Rollup merge of rust-lang#129382 - tgross35:once-cell-const-into-inner, r=Noratrieb Add `const_cell_into_inner` to `OnceCell` `Cell` and `RefCell` have their `into_inner` methods const unstable. `OnceCell` has the same logic, so add it under the same gate. Tracking issue: rust-lang#78729

…dtolnay stabilize const_cell_into_inner This const-stabilizes - `UnsafeCell::into_inner` - `Cell::into_inner` - `RefCell::into_inner` - `OnceCell::into_inner` `@rust-lang/wg-const-eval` this uses `rustc_allow_const_fn_unstable(const_precise_live_drops)`, so we'd be comitting to always finding *some* way to accept this code. IMO that's fine -- what these functions do is to move out the only field of a struct, and that struct has no destructor itself. The field's destructor does not get run as it gets returned to the caller. `@rust-lang/libs-api` this was FCP'd already [years ago](rust-lang#78729 (comment)), except that `OnceCell::into_inner` was added to the same feature gate since then (Cc `@tgross35).` Does that mean we have to re-run the FCP? If yes, I'd honestly prefer to move `OnceCell` into its own feature gate to not risk missing the next release. (That's why it's not great to add new functions to an already FCP'd feature gate.) OTOH if this needs an FCP either way since the previous FCP was so long ago, then we might as well do it all at once.

Rollup merge of rust-lang#130972 - RalfJung:const_cell_into_inner, r=dtolnay stabilize const_cell_into_inner This const-stabilizes - `UnsafeCell::into_inner` - `Cell::into_inner` - `RefCell::into_inner` - `OnceCell::into_inner` `@rust-lang/wg-const-eval` this uses `rustc_allow_const_fn_unstable(const_precise_live_drops)`, so we'd be comitting to always finding *some* way to accept this code. IMO that's fine -- what these functions do is to move out the only field of a struct, and that struct has no destructor itself. The field's destructor does not get run as it gets returned to the caller. `@rust-lang/libs-api` this was FCP'd already [years ago](rust-lang#78729 (comment)), except that `OnceCell::into_inner` was added to the same feature gate since then (Cc `@tgross35).` Does that mean we have to re-run the FCP? If yes, I'd honestly prefer to move `OnceCell` into its own feature gate to not risk missing the next release. (That's why it's not great to add new functions to an already FCP'd feature gate.) OTOH if this needs an FCP either way since the previous FCP was so long ago, then we might as well do it all at once.

a1phyr added the C-tracking-issue Category: A tracking issue for an RFC or an unstable feature. label Nov 4, 2020

a1phyr mentioned this issue Nov 4, 2020

Constantify UnsafeCell::into_inner and related #78728

Merged

LeSeulArtichaut added A-const-fn Area: const fn foo(..) {..}. Pure functions which can be applied at compile time. T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. labels Nov 4, 2020

KodrAus added the Libs-Tracked Libs issues that are tracked on the team's project board. label Nov 6, 2020

rfcbot added proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. disposition-merge This issue / PR is in PFCP or FCP with a disposition to merge it. labels Mar 31, 2021

rfcbot added final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. and removed proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. labels Mar 31, 2021

rfcbot added the finished-final-comment-period The final comment period is finished for this PR / Issue. label Apr 10, 2021

rfcbot added to-announce Announce this issue on triage meeting and removed final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. labels Apr 10, 2021

m-ou-se mentioned this issue Apr 11, 2021

Stabilize const_cell_into_inner. #84087

Closed

apiraino removed the to-announce Announce this issue on triage meeting label Apr 15, 2021

mkroening mentioned this issue Oct 8, 2023

Tracking issue for const_cell_into_inner mkroening/interrupt-ref-cell#3

Open

1 task

dtolnay mentioned this issue Apr 5, 2024

Stabilize const Atomic*::into_inner #123522

Merged

tgross35 added a commit to tgross35/rust that referenced this issue Aug 21, 2024

Add const_cell_into_inner to OnceCell

81c00dd

`Cell` and `RefCell` have their `into_inner` methods const unstable. `OnceCell` has the same logic, so add it under the same gate. Tracking issue: rust-lang#78729

tgross35 mentioned this issue Aug 21, 2024

Add const_cell_into_inner to OnceCell #129382

Merged

RalfJung mentioned this issue Sep 28, 2024

stabilize const_cell_into_inner #130972

Merged

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Tracking Issue for `#![feature(const_cell_into_inner)]` #78729

Tracking Issue for `#![feature(const_cell_into_inner)]` #78729

a1phyr commented Nov 4, 2020 •

edited by tgross35

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m-ou-se commented Mar 31, 2021

rfcbot commented Mar 31, 2021 •

edited by BurntSushi

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rfcbot commented Mar 31, 2021

rfcbot commented Apr 10, 2021

dtolnay commented Apr 5, 2024

tgross35 commented Aug 22, 2024

Tracking Issue for #![feature(const_cell_into_inner)] #78729

Tracking Issue for #![feature(const_cell_into_inner)] #78729

Comments

a1phyr commented Nov 4, 2020 • edited by tgross35 Loading

Steps

m-ou-se commented Mar 31, 2021

rfcbot commented Mar 31, 2021 • edited by BurntSushi Loading

rfcbot commented Mar 31, 2021

rfcbot commented Apr 10, 2021

dtolnay commented Apr 5, 2024

tgross35 commented Aug 22, 2024

Tracking Issue for `#![feature(const_cell_into_inner)]` #78729

Tracking Issue for `#![feature(const_cell_into_inner)]` #78729

a1phyr commented Nov 4, 2020 •

edited by tgross35

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rfcbot commented Mar 31, 2021 •

edited by BurntSushi

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