Type/data instances: require that variables on the RHS are mentioned on the LHS (#23512)
Fixed #23512 (closed)
Now this is rejected with an out-of-scope error:
type family F1 a :: k
type instance F1 Int = Any :: j -> jT23512a.hs:6:31: error: [GHC-76037] Not in scope: type variable ‘j’
T23512a.hs:6:36: error: [GHC-76037] Not in scope: type variable ‘j’