Re: [PATCH v2] rust: bitfield: require integer storage

["Gary Guo" <gary@garyguo.net>]

On Tue Sep 22, 2026 at 2:53 PM BST, Alexandre Courbot wrote:
>>  
>> -        // SAFETY: `$storage` is `Zeroable` and `$name` is transparent.
>> -        unsafe impl ::pin_init::Zeroable for $name {}
>> +        // SAFETY:
>> +        // - `$storage: Integer` is sealed to primitive integer types, for which the all-zero bit
>> +        //   pattern is valid.
>> +        // - `$name` is `repr(transparent)` over `$storage`.
>> +        unsafe impl ::pin_init::Zeroable for $name
>> +        where $storage: ::kernel::num::Integer
>> +        {}
>
> While I guess that would somehow work, I think the proper place to do
> this is the struct definition, i.e:
>
>   $vis struct $name
>   where
>       $storage: $crate::num::Integer,
>   {
>       inner: $storage,
>   }
>
> This makes the error message also more explicit about what the problem
> is (a bitfield requires an `Integer`, not merely the ability to
> initialize it to zero).

Agreed.

Best,
Gary