Mark `trait_upcasting` feature no longer incomplete. This marks the `trait_upcasting` feature no longer incomplete since #101336 has been settled for a little while. r? ``````@jackh726``````
Mark `trait_upcasting` feature no longer incomplete. This marks the `trait_upcasting` feature no longer incomplete since #101336 has been settled for a little while. r? ``````@jackh726``````