Add fn into_raw_with_allocator to Rc/Arc/Weak.
#125093
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... since fn allocator doesn't exist yet.
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…iaskrgr Rollup of 5 pull requests Successful merges: - rust-lang#125034 (Weekly `cargo update`) - rust-lang#125093 (Add `fn into_raw_with_allocator` to Rc/Arc/Weak.) - rust-lang#125282 (Never type unsafe lint improvements) - rust-lang#125301 (fix suggestion in E0373 for !Unpin coroutines) - rust-lang#125302 (defrost `RUST_MIN_STACK=ice rustc hello.rs`) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of rust-lang#125093 - zachs18:rc-into-raw-with-allocator-only, r=Mark-Simulacrum Add `fn into_raw_with_allocator` to Rc/Arc/Weak. Split out from rust-lang#119761 Add `fn into_raw_with_allocator` for `Rc`/`rc::Weak`[^1]/`Arc`/`sync::Weak`. * Pairs with `from_raw_in` (which already exists on all 4 types). * Name matches `Box::into_raw_with_allocator`. * Associated fns on `Rc`/`Arc`, methods on `Weak`s. <details> <summary>Future PR/ACP</summary> As a follow-on to this PR, I plan to make a PR/ACP later to move `into_raw(_parts)` from `Container<_, A: Allocator>` to only `Container<_, Global>` (where `Container` = `Vec`/`Box`/`Rc`/`rc::Weak`/`Arc`/`sync::Weak`) so that users of non-`Global` allocators have to explicitly handle the allocator when using `into_raw`-like APIs. The current behaviors of stdlib containers are inconsistent with respect to what happens to the allocator when `into_raw` is called (which does not return the allocator) | Type | `into_raw` currently callable with | behavior of `into_raw`| | --- | --- | --- | | `Box` | any allocator | allocator is [dropped](https://doc.rust-lang.org/nightly/src/alloc/boxed.rs.html#1060) | | `Vec` | any allocator | allocator is [forgotten](https://doc.rust-lang.org/nightly/src/alloc/vec/mod.rs.html#884) | | `Arc`/`Rc`/`Weak` | any allocator | allocator is [forgotten](https://doc.rust-lang.org/src/alloc/sync.rs.html#1487)(Arc) [(sync::Weak)](https://doc.rust-lang.org/src/alloc/sync.rs.html#2726) [(Rc)](https://doc.rust-lang.org/src/alloc/rc.rs.html#1352) [(rc::Weak)](https://doc.rust-lang.org/src/alloc/rc.rs.html#2993) | In my opinion, neither implicitly dropping nor implicitly forgetting the allocator is ideal; dropping it could immediately invalidate the returned pointer, and forgetting it could unintentionally leak memory. My (to-be) proposed solution is to just forbid calling `into_raw(_parts)` on containers with non-`Global` allocators, and require calling `into_raw_with_allocator`(/`Vec::into_raw_parts_with_alloc`) </details> [^1]: Technically, `rc::Weak::into_raw_with_allocator` is not newly added, as it was modified and renamed from `rc::Weak::into_raw_and_alloc`.
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Split out from #119761
Add
fn into_raw_with_allocatorforRc/rc::Weak1/Arc/sync::Weak.from_raw_in(which already exists on all 4 types).Box::into_raw_with_allocator.Rc/Arc, methods onWeaks.Future PR/ACP
As a follow-on to this PR, I plan to make a PR/ACP later to move
into_raw(_parts)fromContainer<_, A: Allocator>to onlyContainer<_, Global>(whereContainer=Vec/Box/Rc/rc::Weak/Arc/sync::Weak) so that users of non-Globalallocators have to explicitly handle the allocator when usinginto_raw-like APIs.The current behaviors of stdlib containers are inconsistent with respect to what happens to the allocator when
into_rawis called (which does not return the allocator)into_rawcurrently callable withinto_rawBoxVecArc/Rc/WeakIn my opinion, neither implicitly dropping nor implicitly forgetting the allocator is ideal; dropping it could immediately invalidate the returned pointer, and forgetting it could unintentionally leak memory. My (to-be) proposed solution is to just forbid calling
into_raw(_parts)on containers with non-Globalallocators, and require callinginto_raw_with_allocator(/Vec::into_raw_parts_with_alloc)Footnotes
Technically,
rc::Weak::into_raw_with_allocatoris not newly added, as it was modified and renamed fromrc::Weak::into_raw_and_alloc. ↩