Short file produces panic on ghc-9.2.2
The file below produces a panic on ghc-9.2.2:
import Data.Map
type family IxValue (m :: *) :: *
type family Index (m :: *) :: *
data Op a where
Insert :: (a ~ Map (Index a) (IxValue a)) => (Int, Index a, IxValue a) -> Op a
instance Ord a => Ord (Op a) where
compare (Insert a1) (Insert b1) = compare a1 b1
Sorry I don't have access to head right now.