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We do not separate types > for those two concepts. This is getting backwards though, and won't work when we need to introduce lifetimes. Per-fd data needs to be able to reference whatever lifetime is available on per-reg data, so it should be assoc type of the per-reg data type. The way around you current have causes `T::RegistrationData` to be able to referenc= e lifetimes on `T` which is not okay and would only work with `'static` data. Best, Gary > > Alice