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diff --git a/testsuite/tests/backpack/should_fail/T23344.bkp b/testsuite/tests/backpack/should_fail/T23344.bkp
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+++ b/testsuite/tests/backpack/should_fail/T23344.bkp
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+{-# LANGUAGE StandaloneKindSignatures #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE ImpredicativeTypes #-}
+
+unit p where
+  module M where
+    import Data.Kind
+
+    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
+    import Data.Kind
+
+    type S1 :: Type -> Type
+    data S1 a = MkS1
+
+    type S2 :: Type
+    data S2 = MkS2
+
+    type G :: Type -> Constraint
+    class G a where {}
+
+    type T1 = S1 (forall (a :: Type). a -> a)
+    type T2 = S1 (G S2 => S2)
+
+    type Y = forall a. a -> a
+    type Z = Y
+    type T3 = S1 Y
+
+unit s where
+  dependency p
+  dependency r
+  dependency q[H=r:H]