Re: [PATCH v2] rust: pin-init: add `#[bind]` attribute to access previously initialized fields

["Benno Lossin" <lossin@kernel.org>]

On Wed Sep 10, 2025 at 12:40 PM CEST, Alice Ryhl wrote:
> On Wed, Sep 10, 2025 at 12:36 PM Benno Lossin <lossin@kernel.org> wrote:
>>
>> On Wed Sep 10, 2025 at 12:17 PM CEST, Alice Ryhl wrote:
>> > On Wed, Sep 10, 2025 at 12:07:53PM +0200, Benno Lossin wrote:
>> >> Assigning a field a value in an initializer macro can be marked with the
>> >> `#[bind]` attribute. Doing so creates a `let` binding with the same
>> >> name. This `let` binding has the type `Pin<&mut T>` if the field is
>> >> structurally pinned or `&mut T` otherwise (where `T` is the type of the
>> >> field).
>> >>
>> >> Signed-off-by: Benno Lossin <lossin@kernel.org>
>> >
>> > Is there a reason we can't apply this to all fields and avoid the
>> > attribute?
>>
>> Adding the attribute was due to Boqun's concern on v1 [1]. I think it
>> might be surprising too, but I'm also happy with no attribute.
>>
>> [1]: https://lore.kernel.org/all/aLshd0_C-1rh3FAg@tardis-2.local
>
> IMO the ideal is if it works without an attribute. Perhaps trying that
> in the kernel is a reasonable experiment to find out whether that's
> reasonable to do for the general language feature?

@Boqun what is your opinion on this?

I'm open to take v2 or v1, whatever you guys prefer.

---
Cheers,
Benno