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+
+-- Check that we do something sensible when we implement
+-- abstract data with a quantified type.
+
+{-# LANGUAGE StandaloneKindSignatures #-}
+{-# LANGUAGE TypeFamilies #-}
+
+unit p where
+  module M where
+    import Data.Kind ( Type, Constraint )
+
+    type C :: Type -> Constraint
+    class C a where
+      type family F a :: Type
+
+unit q where
+  dependency p
+  signature H where
+    data T1
+    data T2
+    data T3
+  module N where
+    import M ( C(F) )
+    import H ( T1, T2, T3 )
+
+    instance C T1 where
+      type F T1 = T2
+    instance C T2 where
+      type F T2 = T3
+    instance C T3 where
+      type F T3 = T1
+
+unit r where
+  dependency p
+  module H where
+
+    class C2 a where {}
+    data S = MkS
+
+    type T1 = forall a. a -> a
+    type T2 = forall a. C2 a => a
+    type T3 = C2 S => S -> S
+
+unit s where
+  dependency p
+  dependency r
+  dependency q[H=r:H]