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diff --git a/testsuite/tests/boxy/Base1.hs b/testsuite/tests/boxy/Base1.hs
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+{-# OPTIONS_GHC -XImpredicativeTypes -fno-warn-deprecated-flags #-}
+
+module Base1 where 
+-- basic examples of impredicative instantiation of variables 
+
+data MEither a b = MLeft a 
+                 | MRight b 
+                 | MEmpty
+
+type Sid = forall a. a -> a 
+
+-- no need for impredicativity 
+test0 = MRight id 
+
+-- requires impredicativity 
+test1 :: Sid -> MEither Sid b
+test1 fid = MLeft fid 
+
+test2 :: MEither b Sid -> Maybe (Sid,Sid) 
+test2 m = case (test1 id) of 
+             MLeft x -> case m of 
+                          MRight y -> Just (x,y) 
+                          _ -> Nothing 
+             _ -> Nothing
+
+test3 :: MEither a b -> b
+test3 (MRight x) = x 
+
+test4 = test3 (test1 id) 
+