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Date: Mon, 27 May 2024 09:05:38 +0000
To: Alice Ryhl <aliceryhl@google.com>, mu001999 <mu001999@outlook.com>
From: Benno Lossin <benno.lossin@proton.me>
Cc: ojeda@kernel.org, boqun.feng@gmail.com, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] rust: kernel: make impl_has_work compatible with more complex generics
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On 22.05.24 14:37, Alice Ryhl wrote:
> On Wed, May 22, 2024 at 2:27=E2=80=AFPM mu001999 <mu001999@outlook.com> w=
rote:
>>  impl_has_work! {
>> -    impl<T> HasWork<Self> for ClosureWork<T> { self.work }
>> +    impl{T} HasWork<Self> for ClosureWork<T> { self.work }
>>  }
>=20
> I ended up doing something similar for the generics in some of the
> linked list patches. Does anyone know if it's possible to support this
> without giving up the <T> syntax?

I tried to come up with something some time ago, but it was not really
nice. You have to parse the entire generics manually, which ends up
looking horrible. I have been thinking some time now that a `generics`
fragment would actually be really useful in declarative macros.

I also thought that if we get even more `Has*` traits for intrusive
datastructures, we could add a unified derive macro that allows you to
just do:

    #[derive(Intrusive)]
    struct MyStruct {
        #[intrusive]
        work: Work<Self>,
        #[intrusive]
        timer: Timer<Self>,
        /* ... */
    }

But I thought that as long as we have only two intrusive structures, we
don't need this.

---
Cheers,
Benno