src/HOL/Tools/Quickcheck/PNF_Narrowing_Engine.hs

 checkOf :: Generated_Code.Property -> [Generated_Code.Narrowing_term] -> Bool
 checkOf (Generated_Code.Property b) = (\[] -> b)
 checkOf (Generated_Code.Universal _ f _) = (\(t : ts) -> checkOf (f t) ts)
 checkOf (Generated_Code.Existential _ f _) = (\(t : ts) -> checkOf (f t) ts)
 
-dummy = Generated_Code.Var [] (Generated_Code.SumOfProd [[]])
+dummy = Generated_Code.Narrowing_variable [] (Generated_Code.Narrowing_sum_of_products [[]])
 
 treeOf :: Int -> Generated_Code.Property -> QuantTree
 treeOf n (Generated_Code.Property _) = Node uneval
 treeOf n (Generated_Code.Universal ty f _)  = VarNode UniversalQ uneval [n] ty (treeOf (n + 1) (f dummy)) 
 treeOf n (Generated_Code.Existential ty f _) = VarNode ExistentialQ uneval [n] ty (treeOf (n + 1) (f dummy))