Representation guarantee?

[Rua]

Is there a guarantee that Aligned<A, T> has the same memory representation as T, and is thus sound to transmute to T?

[MabezDev]

My understanding is:

• The alignment struct is repr(C)
• ZSTs are ignored when a struct is repr(C)
• Alignment is ensured via a ZST array.
• The layout should therefore be the same as if it were T itself

I am not the original author of the library, so this might not be correct. In practice, however, this is how it works with current versions of the Rust compiler.

[randommm]

I came here to open an issue on this topic, before noticing that there is one already.

Shouldn't this be using repr(transparent) instead of repr(C)? (e.g.: see https://doc.rust-lang.org/nomicon/other-reprs.html) If not, then I think it's a good idea to add an inline comment on why on the struct definition.