1 files changed, 43 insertions, 0 deletions
diff --git a/testsuite/tests/typecheck/should_run/tcrun024.hs b/testsuite/tests/typecheck/should_run/tcrun024.hs
new file mode 100644
index 0000000000..82c6f49e33
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+++ b/testsuite/tests/typecheck/should_run/tcrun024.hs
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+{-# LANGUAGE ImplicitParams, TypeSynonymInstances, FlexibleInstances #-}
+
+-- Class ops that bind no new type variables
+
+module Main where
+
+	import Data.List( sort )
+	
+	just = [Just "fred",Just "bill"]
+
+	main = do { putStrLn (let ?p = "ok1" in fc1);  
+		    putStrLn (let ?p = "ok2" in fc2);  
+		    putStrLn (show (fd1 just)) ;
+		    putStrLn (show (fd2 just)) }
+
+	-- This class has no tyvars in its class op context
+	-- One uses a newtype, the other a data type
+	class C1 a where
+	    fc1 :: (?p :: String) => a;
+	class C2 a where
+	    fc2 :: (?p :: String) => a;
+	    opc :: a
+
+	instance C1 String where
+	    fc1 = ?p;
+	instance C2 String where
+	    fc2 = ?p;
+	    opc = "x"
+
+	-- This class constrains no new type variables in 
+	-- its class op context
+	class D1 a where
+	    fd1 :: (Ord a) => [a] -> [a]
+	class D2 a where
+	    fd2 :: (Ord a) => [a] -> [a]
+	    opd :: a
+
+	instance D1 (Maybe a) where
+	    fd1 xs = sort xs
+	instance D2 (Maybe a) where
+	    fd2 xs = sort xs
+	    opd = Nothing
+