Teach transmute_{ref,mut}! to handle slice DSTs #1924
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joshlf
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I wonder if we could use the autoref trick to get T: Sized to work. Specifically, we could provide one impl for T: Sized as the default, and then a fallback to T: KnownLayout |
Yes, I believe we can: https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=78af21ee715df8622ed1b28433a1d314 |
Makes progress on #1009 gherrit-pr-id: I3d825b6c6b99277c96d9fd6a6761bdfad2000473
This permits us to remove the `KnownLayout` bounds from `Ptr::transmute`, and thus to remove `Ptr::transmute_sized` entirely. This also allows us to remove the hand-rolled impl of `TryFromBytes` for `ManuallyDrop<T>`, replacing it with an invocation of `impl_for_transmute_from!`. gherrit-pr-id: I090715fd9ed6f100fd35513b05054015621ecb9c
jswrenn
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TODO: - Figure out how to make this backwards-compatible (since current macros work with `T: Sized`, but `T: Sized` does not imply `T: KnownLayout`) - Make it so that `Sized` bounds are still enforced on older toolchains that don't support slice DST transmutes - Write safety comments - Get rid of now-unused macros and functions in util::macro_util Makes progress on #1817 gherrit-pr-id: Ib4bc62202e0b3b09d155333b525087f7aa8f02c2
jswrenn
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Closing in favor of #2428 |
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TODO:
T: Sized, butT: Sizeddoes not implyT: KnownLayout)Sizedbounds are still enforced on older toolchains that don't support slice DST transmutesMakes progress on #1817
gherrit-pr-id: Ib4bc62202e0b3b09d155333b525087f7aa8f02c2