Guarantee that raw pointer conversions preserve slice element count #1417
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This encodes the behavior agreed upon in rust-lang/unsafe-code-guidelines#288.
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Friendly ping 🙂 |
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Nominating for lang, but I'm not sure if they would defer this decision to someone else, like t-opsem. cc @RalfJung |
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@rfcbot fcp merge We discussed in the @rust-lang/lang meeting today and meeting consensus was to merge this. Documenting that. |
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Team member @nikomatsakis 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! cc @rust-lang/lang-advisors: FCP proposed for lang, please feel free to register concerns. |
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This sounds like a lang decision to me, since it's about stable guarantees of how a type works. Still Cc @rust-lang/opsem |
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I think this is often sketchy, and it might overall be better to encourage @rfcbot reviewed |
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🔔 This is now entering its final comment period, as per the review above. 🔔 psst @nikomatsakis, I wasn't able to add the |
Also worth noting that |
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@rustbot labels -I-lang-nominated This was discussed today and is now in FCP. We'll remove the nomination. |
Co-authored-by: Niko Matsakis <niko@alum.mit.edu>
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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. This will be merged soon. psst @nikomatsakis, I wasn't able to add the |
Update books ## rust-lang/reference 4 commits in 16fd3c06d9e558dae2d52000818274ae70c9e90a..cd8193e972f61b92117095fc73b67af767b4d6bc 2023-11-04 17:19:39 UTC to 2023-10-30 16:04:52 UTC - Guarantee that raw pointer conversions preserve slice element count (rust-lang/reference#1417) - some asm block flags also mean there can be no fences (rust-lang/reference#1413) - Guarantee `char` layout (rust-lang/reference#1401) - Doc: Add the RISC-V stabilized target features (rust-lang/reference#1415) ## rust-lang/rust-by-example 3 commits in 6709beeb7d0fbc5ffc91ac4893a24434123b9bfa..311b84962016b28c75525c86e7b3f49fd9101a39 2023-10-31 18:32:09 UTC to 2023-10-31 18:30:39 UTC - Fixed explanation mistake in comment (rust-lang/rust-by-example#1761) - Fix typos (rust-lang/rust-by-example#1759) - docs(9.2): fix typo (rust-lang/rust-by-example#1754) ## rust-lang/rustc-dev-guide 6 commits in b0ee9ec..77dbe57 2023-11-06 16:14:34 UTC to 2023-10-29 17:16:02 UTC - add a new type system invariant (rust-lang/rustc-dev-guide#1822) - Update some outdated descriptions of coverage instrumentation (rust-lang/rustc-dev-guide#1809) - Add some documentation for unsizing (rust-lang/rustc-dev-guide#1817) - Bibliography: fixing author of "You Can't Spell Trust Without Rust" (rust-lang/rustc-dev-guide#1815) - remove change-id from sample build configuration (rust-lang/rustc-dev-guide#1813) - Update name of "active" features to "unstable" (rust-lang/rustc-dev-guide#1814)
Rollup merge of rust-lang#117639 - rustbot:docs-update, r=ehuss Update books ## rust-lang/reference 4 commits in 16fd3c06d9e558dae2d52000818274ae70c9e90a..cd8193e972f61b92117095fc73b67af767b4d6bc 2023-11-04 17:19:39 UTC to 2023-10-30 16:04:52 UTC - Guarantee that raw pointer conversions preserve slice element count (rust-lang/reference#1417) - some asm block flags also mean there can be no fences (rust-lang/reference#1413) - Guarantee `char` layout (rust-lang/reference#1401) - Doc: Add the RISC-V stabilized target features (rust-lang/reference#1415) ## rust-lang/rust-by-example 3 commits in 6709beeb7d0fbc5ffc91ac4893a24434123b9bfa..311b84962016b28c75525c86e7b3f49fd9101a39 2023-10-31 18:32:09 UTC to 2023-10-31 18:30:39 UTC - Fixed explanation mistake in comment (rust-lang/rust-by-example#1761) - Fix typos (rust-lang/rust-by-example#1759) - docs(9.2): fix typo (rust-lang/rust-by-example#1754) ## rust-lang/rustc-dev-guide 6 commits in b0ee9ec..77dbe57 2023-11-06 16:14:34 UTC to 2023-10-29 17:16:02 UTC - add a new type system invariant (rust-lang/rustc-dev-guide#1822) - Update some outdated descriptions of coverage instrumentation (rust-lang/rustc-dev-guide#1809) - Add some documentation for unsizing (rust-lang/rustc-dev-guide#1817) - Bibliography: fixing author of "You Can't Spell Trust Without Rust" (rust-lang/rustc-dev-guide#1815) - remove change-id from sample build configuration (rust-lang/rustc-dev-guide#1813) - Update name of "active" features to "unstable" (rust-lang/rustc-dev-guide#1814)
Since raw pointer slice casts are now guaranteed to preserve element count [1], we no longer need to separately store the byte length of a `Ptr`. Instead, we can compute it from the raw pointer field. [1] rust-lang/reference#1417
Since raw pointer slice casts are now guaranteed to preserve element count [1], we no longer need to separately store the byte length of a `Ptr`. Instead, we can compute it from the raw pointer field. [1] rust-lang/reference#1417
Since raw pointer slice casts are now guaranteed to preserve element count [1], we no longer need to separately store the byte length of a `Ptr`. Instead, we can compute it from the raw pointer field. [1] rust-lang/reference#1417
This encodes the behavior agreed upon in rust-lang/unsafe-code-guidelines#288.