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Mark {array, slice}::{from_ref, from_mut} as const fn #90162

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merged 3 commits into from
Oct 24, 2021

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WaffleLapkin
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This PR marks the following APIs as const:

// core::array
pub const fn from_ref<T>(s: &T) -> &[T; 1];
pub const fn from_mut<T>(s: &mut T) -> &mut [T; 1];

// core::slice
pub const fn from_ref<T>(s: &T) -> &[T];
pub const fn from_mut<T>(s: &mut T) -> &mut [T];

Note that from_ref methods require const_raw_ptr_deref feature (which seems totally fine, since it's being stabilized, see #89551), from_mut methods require const_mut_refs (which seems fine too since this PR marks from_mut functions as const unstable).

r? @oli-obk

@rust-highfive rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Oct 22, 2021
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oli-obk commented Oct 22, 2021

These changes all lgtm.

Please add a tracking issue and tests. Once raw ptr deref is stabilized we can immediately ask the libs team for stabilization of the immutable parts

@WaffleLapkin
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@oli-obk done. Not sure if the tests make sense, but I've tried 😅

Also, maybe we want to separate features for &/&mut version? It seems like we'll stabilize the &mut versions a lot later.

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oli-obk commented Oct 24, 2021

We can just stabilise the immutable functions and leave the gate for the mutable ones.

The tests are great

@bors r+

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bors commented Oct 24, 2021

📌 Commit 5f390cf has been approved by oli-obk

@bors bors 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 Oct 24, 2021
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Oct 24, 2021
…_ref_mut, r=oli-obk

Mark `{array, slice}::{from_ref, from_mut}` as const fn

This PR marks the following APIs as `const`:
```rust
// core::array
pub const fn from_ref<T>(s: &T) -> &[T; 1];
pub const fn from_mut<T>(s: &mut T) -> &mut [T; 1];

// core::slice
pub const fn from_ref<T>(s: &T) -> &[T];
pub const fn from_mut<T>(s: &mut T) -> &mut [T];
```

Note that `from_ref` methods require `const_raw_ptr_deref` feature (which seems totally fine, since it's being stabilized, see rust-lang#89551), `from_mut` methods require `const_mut_refs` (which seems fine too since this PR marks `from_mut` functions as const unstable).

r? `@oli-obk`
This was referenced Oct 24, 2021
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Oct 24, 2021
…_ref_mut, r=oli-obk

Mark `{array, slice}::{from_ref, from_mut}` as const fn

This PR marks the following APIs as `const`:
```rust
// core::array
pub const fn from_ref<T>(s: &T) -> &[T; 1];
pub const fn from_mut<T>(s: &mut T) -> &mut [T; 1];

// core::slice
pub const fn from_ref<T>(s: &T) -> &[T];
pub const fn from_mut<T>(s: &mut T) -> &mut [T];
```

Note that `from_ref` methods require `const_raw_ptr_deref` feature (which seems totally fine, since it's being stabilized, see rust-lang#89551), `from_mut` methods require `const_mut_refs` (which seems fine too since this PR marks `from_mut` functions as const unstable).

r? ``@oli-obk``
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Oct 24, 2021
…_ref_mut, r=oli-obk

Mark `{array, slice}::{from_ref, from_mut}` as const fn

This PR marks the following APIs as `const`:
```rust
// core::array
pub const fn from_ref<T>(s: &T) -> &[T; 1];
pub const fn from_mut<T>(s: &mut T) -> &mut [T; 1];

// core::slice
pub const fn from_ref<T>(s: &T) -> &[T];
pub const fn from_mut<T>(s: &mut T) -> &mut [T];
```

Note that `from_ref` methods require `const_raw_ptr_deref` feature (which seems totally fine, since it's being stabilized, see rust-lang#89551), `from_mut` methods require `const_mut_refs` (which seems fine too since this PR marks `from_mut` functions as const unstable).

r? ```@oli-obk```
This was referenced Oct 24, 2021
bors added a commit to rust-lang-ci/rust that referenced this pull request Oct 24, 2021
…askrgr

Rollup of 6 pull requests

Successful merges:

 - rust-lang#89558 (Add rustc lint, warning when iterating over hashmaps)
 - rust-lang#90100 (Skip documentation for tier 2 targets on dist-x86_64-apple-darwin)
 - rust-lang#90155 (Fix alignment of method headings for scannability)
 - rust-lang#90162 (Mark `{array, slice}::{from_ref, from_mut}` as const fn)
 - rust-lang#90221 (Fix ICE when forgetting to `Box` a parameter to a `Self::func` call)
 - rust-lang#90234 (Temporarily turn overflow checks off for rustc-rayon-core)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit c16ee19 into rust-lang:master Oct 24, 2021
@rustbot rustbot added this to the 1.58.0 milestone Oct 24, 2021
@WaffleLapkin WaffleLapkin deleted the const_array_slice_from_ref_mut branch May 23, 2022 11:56
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5 participants