diff --git a/haskell/Pre.hs b/haskell/Pre.hs
index 9be14d6..3493f6a 100644
--- a/haskell/Pre.hs
+++ b/haskell/Pre.hs
@@ -298,7 +298,6 @@ data TestFailure
     = ExceptionFailure SomeException
     | AssertionFailure Text
     | GoldenFailure {expected :: Text, actual :: Text}
-    deriving (Show)
 
 newtype TestName = TestName Text