1 files changed, 27 insertions, 0 deletions
diff --git a/testsuite/tests/boxy/Church2.hs b/testsuite/tests/boxy/Church2.hs
new file mode 100644
index 0000000000..c360bb3a8b
--- /dev/null
+++ b/testsuite/tests/boxy/Church2.hs
@@ -0,0 +1,27 @@
+{-# LANGUAGE RankNTypes #-}
+
+module Church2 where 
+-- Church numerals w/o extra type constructors: Should fail
+
+type CNat = forall a. (a->a) -> a -> a 
+
+n0 :: CNat 
+n0 = \f z -> z
+
+n1 :: CNat 
+n1 = \f z -> f z 
+
+nsucc :: CNat -> CNat 
+nsucc n = \f z -> f (n f z)
+
+add, mul :: CNat -> CNat -> CNat
+add m n = \f -> \a -> m f (n f a)
+mul m n = \f -> \a -> m (n f) a
+
+-- already works with GHC 6.4 
+exp0 :: CNat -> CNat -> CNat 
+exp0 m n = n m
+
+-- should fail! 
+exp2 :: CNat -> CNat -> CNat 
+exp2 m n = n (mul m) n1