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Jacob Pratt
e002c6c726
Generalize IO Traits for `Arc<T>` where `&T: IoTrait` ACP: https://github.com/rust-lang/libs-team/issues/755 Tracking issue: https://github.com/rust-lang/rust/issues/154046 Related: rust-lang/rust#94744 ## Description After experimenting with rust-lang/rust#155625, I noticed `Seek` and `SeekFrom` can almost be moved to `core::io`. Unfortunately, the implementation of `Seek` for `Arc<File>` is a blocker for such a move, since `Arc` is not a fundamental type. This PR attempts to resolve this potential blocker by replacing the implementation with a more general alternative. An internal trait `IoHandle` has been added which types can implement to opt-in to `Read`/`Write`/`Seek` implementations for `Arc<Self>` as long as `&Self` implements said trait. Note that `BufRead` is excluded as the signature for `fill_buf` would require returning from a temporary. Since this "blanket" implementation only applies to a single type which already implements the same traits, I believe this should have no user-facing impact. If this PR was merged, rust-lang/rust#134190 could be replaced with a 2 line PR: ```rust impl IoHandle for TcpStream {} impl IoHandle for UnixStream {} ``` Likewise for any other types, a table of which can be found [here](https://github.com/rust-lang/libs-team/issues/504#issuecomment-2539569736). This is out of scope for this PR to avoid the need for an ACP. --- ## Notes * See [this comment](https://github.com/rust-lang/rust/issues/154046#issuecomment-4303975612) for further details. * No AI tooling of any kind was used during the creation of this PR.