Re: [PATCH] rust: pin-init: add references to previously initialized fields

["Danilo Krummrich" <dakr@kernel.org>]

On Mon Sep 8, 2025 at 10:27 AM CEST, Benno Lossin wrote:
> On Mon Sep 8, 2025 at 4:08 AM CEST, Boqun Feng wrote:
>> On Mon, Sep 08, 2025 at 01:33:26AM +0200, Danilo Krummrich wrote:
>>> On Mon Sep 8, 2025 at 12:51 AM CEST, Benno Lossin wrote:
>>> > I actually came up with a third option that looks best IMO:
>>> >
>>> >     init!(MyStruct {
>>> >         x: 42,
>>> >         #[with_binding]
>>> >         y: 24,
>>> >         z: *y,
>>> >     })
>>> >
>>> > The `#[with_binding]` attribute makes the macro generate a variable `y`.
>>> > `x` & `z` don't give access to their value. (we of course should come up
>>> > with a better name).
>>> >
>>> > Any thoughts?
>>> 
>>> It may be a bit verbose is some cases, but it makes things pretty obvious, so
>>> LGTM.
>>> 
>>> How about just #[bind] or #[access]?
>
> I like `#[bind]`.
>
>> #[shadow] or #[maybe_rebind] ? Or #[pin_ref], the last one is clear
>> about the purpose.
>
> Hmm in `init!` it's never pinned.

I thought about #[shadow] as well, but it is not really accurate I think, as we
might not shadow anything. #[maybe_rebind] sounds a bit like it conditionally
rebinds, as in "it may not do anything", but it always binds.

So, I think it should one clear instruction, i.e. #[bind], #[access], #[ref],
#[use], #[let], etc.