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diff --git a/testsuite/tests/impredicative/Base1.hs b/testsuite/tests/impredicative/Base1.hs
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+{-# LANGUAGE ImpredicativeTypes #-}
+
+-- Sept 16: now failing, because I've further reduced the scop
+--          of impredicative types
+
+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)
+