Visitors track whether an assoc item is in a trait impl or an inherent impl `AssocCtxt::Impl` now contains an `of_trait` field. This allows ast lowering and nameres to not have to track whether we're in a trait impl or an inherent impl.
Visitors track whether an assoc item is in a trait impl or an inherent impl `AssocCtxt::Impl` now contains an `of_trait` field. This allows ast lowering and nameres to not have to track whether we're in a trait impl or an inherent impl.