Re: [PATCH 0/8] rust: io: register: allow paths for relative register bases

[Gary Guo]

On Tue Jul 21, 2026 at 4:02 PM BST, Alexandre Courbot wrote:
> On Tue Jul 21, 2026 at 7:34 AM PDT, Gary Guo wrote:
>> On Tue Jul 21, 2026 at 12:00 PM BST, Alexandre Courbot wrote:
>>> The register! macro currently accepts an identifier as the base of a
>>> relative register. This requires base types declared in other modules to
>>> be imported into the module containing the register declaration, rather
>>> than allowing a qualified path to be used directly, which is arbitrarily
>>> limiting.
>>>
>>> This series allows path to be used as relative register bases. Since a
>>> `path` fragment cannot be followed by `+` in declarative macros, the
>>> `Base + Offset` and `Base + Alias` forms are replaced with `Base:
>>> Offset` and `Base: Alias`, inducing a syntax change.
>>>
>>> The first two patches clean up the macro's internal dispatch and
>>> arguments in preparation for the change. Patches 3-6 gradually add
>>> support for the new syntax and update docs and examples, while
>>> preserving the old syntax. Patch 7 updates Nova to use the new syntax,
>>> and patch 8 removes support for the now unused old syntax.
>>>
>>> The series is structured this way so the Nova update and deprecated
>>> syntax removal can be merged separately, as otherwise the whole series
>>> would need to go through drm-rust.
>>
>> I would like to avoid adding new features to relative registers as I aspire to
>> get rid of them entirely with typed registers.
>
> This is a fix rather than a new feature. Relative register bases should
> have been captured as a path since the beginning.
>
> I'll be glad to remove relative registers entirely if projections can
> cover their use-case better, but I would not withhold a fix while a
> replacement is not visible yet.

I'm not seeing this as a fix. Nova doesn't need to use a path, and requiring an
import is hardly a restriction.

Best,
Gary