Fixed unsoundness of using &mut MaybeUninit<T> as the out type for …
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HeroicKatora
suggested changes
Jan 30, 2020
It features: - enhancing `Vec::reserve_uninit` to a more general API for accessing with the backing buffer / capacity of a Vec; - Rename `idx` to `.get_out` - (Ab)use `.copy_from_slice()` in read implementations to use less unsafe TODO: - The iterator API, - Documentation Co-Authored-By: Andreas Molzer <[email protected]>
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Not only does this lead to replacing `OutSlice<T>` with the more readable `Out<[T]>`, it also results in other parts of the API being greatly simplified (mainly the `AsOut` trait).
Co-Authored-By: Andreas Molzer <[email protected]>
danielhenrymantilla
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This (WIP) PR objective is to fix the issues spotted by @Kixunil (thanks for telling me!):
Minor: using
transmuteon fat references makes incorrect assumptions about their layout, so that code could break in a future version of Rust.slice::from_raw_parts{,_mut}instead.MAJOR: The API used
&mut MaybeUninit<_>as its&outreference type, assuming that it was sound to transmute between&mut Tand&mut MaybeUninit<T>, which it is not (see Document that casting &mut T to &mut MaybeUninit<T> is not safe rust-lang/rust#66699)&outreferences that does not let writingMaybeUninit::uninit()into the pointee.Added some API features, such as being able to forge a
&out Tfrom&mut ManuallyDrop<T>(to offer&outrefs even whenT : !Copyand could thus have drop glue (although leaking is safe, I take an opinionated stance here that so doing ought to be visible and thus verbose)@HeroicKatora do you wanna review this?
TODO:
Document new methods
Add extra helpers to
Outreferences