On Tue, Mar 07, 2023 at 11:25:43PM +0900, Asahi Lina wrote: > +/// Look up a GEM object handle for a `File` and return an `ObjectRef` for it. > +pub(crate) fn lookup_handle(file: &DrmFile, handle: u32) -> Result<ObjectRef> { > + Ok(ObjectRef::new(shmem::Object::lookup_handle(file, handle)?)) > +} So maybe my expectations for rust typing is a bit too much, but I kinda expected this to be fully generic: - trait Driver (drm_driver) knows the driver's object type - a generic create_handle function could ensure that for drm_file (which is always for a specific drm_device and hence Driver) can ensure at the type level that you only put the right objects into the drm_file - a generic lookup_handle function on the drm_file knows the Driver trait and so can give you back the right type right away. Why the wrapping, what do I miss? -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch