Typed Racket v7.0 Prefab Changes
For some time now, Typed Racket has unsoundly type checked prefab structs. This bug been fixed for the Racket v7.0 release (for more info, see the relevant Typed Racket RFC and the illustrative examples in the Prefab section of the docs). If you suspect your prefab-utilizing Typed Racket code no longer type checks because of this fix, we hope the below instructions help make any necessary changes as painless as possible. We apologize for any inconvenience. If you believe there are issues/fixes that should be added to this list, please do let us know.