Re: [PATCH v3 1/9] rust: add offset_of! macro

["Andreas Hindborg (Samsung)" <nmi@metaspace.dk>]

Hi Alice,

Alice Ryhl <aliceryhl@google.com> writes:

> From: Wedson Almeida Filho <walmeida@microsoft.com>
>
> This macro is used to compute the offset of a field in a struct.
>
> This commit enables an unstable feature that is necessary for using
> the macro in a constant. However, this is not a problem as the macro
> will become available from the Rust standard library soon [1]. The
> unstable feature can be disabled again once that happens.
>
> The macro in this patch does not support sub-fields. That is, you cannot
> write `offset_of!(MyStruct, field.sub_field)` to get the offset of
> `sub_field` with `field`'s type being a struct with a field called
> `sub_field`. This is because `field` might be a `Box<SubStruct>`, which
> means that you would be trying to compute the offset to something in an
> entirely different allocation. There's no easy way to fix the current
> macro to support subfields, but the version being added to the standard
> library should support it, so the limitation is temporary and not a big
> deal.

I think `#![feature(offset_of)]` is available in 1.71.0, can we use that directly?

BR Andreas