format safety doc of Rc/Arc::from_raw/from_raw_in#154081
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rust-bors[bot] merged 1 commit intorust-lang:mainfrom Mar 28, 2026
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format safety doc of Rc/Arc::from_raw/from_raw_in#154081rust-bors[bot] merged 1 commit intorust-lang:mainfrom
rust-bors[bot] merged 1 commit intorust-lang:mainfrom
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hkBst
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| /// | ||
| /// * Creating a `Rc<T>` from a pointer other than one returned from | ||
| /// [`Rc<U>::into_raw`][into_raw] or [`Rc<U>::into_raw_with_allocator`][into_raw_with_allocator] | ||
| /// is undefined behavior. |
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I'm guessing it is also undefined behavior if the pointer came from a call to into_raw_with_allocator where the returned allocator was not the global one.
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Yes, but there is another safety requirement in the safety section preventing this: the raw pointer must point to a block of memory allocated by the global allocator.
| /// | ||
| /// The raw pointer must have been previously returned by a call to | ||
| /// [`Rc<U>::into_raw`][into_raw] with the following requirements: | ||
| /// [`Rc<U>::into_raw`][into_raw] or [`Rc<U>::into_raw_with_allocator`][into_raw_with_allocator]. |
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This information is now duplicated in the safety section, but there it is phrased negatively instead. Should perhaps this positive version be moved into the safety section instead?
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I referred to the format used in Thread::from_raw, which follows the same pattern.
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@bors r+ rollup |
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Rollup of 9 pull requests Successful merges: - #154357 (uefi: extend comment for TcpStream Send impl) - #154410 (Clean up the API for opening/checking incremental-compilation files ) - #154081 (format safety doc of Rc/Arc::from_raw/from_raw_in) - #154110 (Change "error finalizing incremental compilation" text and emit it as a note, not a warning) - #154196 (Make `Ipv6Addr::multicast_scope()` exhaustive) - #154221 (`vec::as_mut_slice()`: use lowercase "isize" in safety comment) - #154234 (Use common Timestamp impl in Hermit (attempt 2)) - #154396 (chore(deps): update rust crate tar to v0.4.45) - #154488 (Revert "Unstable book options parser")
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Rollup of 9 pull requests Successful merges: - #154357 (uefi: extend comment for TcpStream Send impl) - #154410 (Clean up the API for opening/checking incremental-compilation files ) - #154081 (format safety doc of Rc/Arc::from_raw/from_raw_in) - #154110 (Change "error finalizing incremental compilation" text and emit it as a note, not a warning) - #154196 (Make `Ipv6Addr::multicast_scope()` exhaustive) - #154221 (`vec::as_mut_slice()`: use lowercase "isize" in safety comment) - #154234 (Use common Timestamp impl in Hermit (attempt 2)) - #154396 (chore(deps): update rust crate tar to v0.4.45) - #154488 (Revert "Unstable book options parser")
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Rollup merge of #154081 - safer-rust:main, r=Mark-Simulacrum format safety doc of Rc/Arc::from_raw/from_raw_in The following APIs previously had safety notes, but they were not placed under a dedicated Safety section. This PR adds a Safety section for each API and moves the original safety descriptions there: - [`Rc::from_raw`](https://doc.rust-lang.org/nightly/alloc/rc/struct.Rc.html#method.from_raw) - [`Rc::from_raw_in`](https://doc.rust-lang.org/nightly/alloc/rc/struct.Rc.html#method.from_raw_in) - [`Arc::from_raw`](https://doc.rust-lang.org/nightly/alloc/sync/struct.Arc.html#method.from_raw) - [`Arc::from_raw_in`](https://doc.rust-lang.org/nightly/alloc/sync/struct.Arc.html#method.from_raw_in) Additionally, we updated the parameter requirements to clarify that the raw pointer may be returned not only from `into_raw`, but also from `into_raw_with_allocator`.
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The following APIs previously had safety notes, but they were not placed under a dedicated Safety section. This PR adds a Safety section for each API and moves the original safety descriptions there:
Rc::from_rawRc::from_raw_inArc::from_rawArc::from_raw_inAdditionally, we updated the parameter requirements to clarify that the raw pointer may be returned not only from
into_raw, but also frominto_raw_with_allocator.