diff --git a/io-classes/src/Control/Monad/Class/MonadSTM/Internal.hs b/io-classes/src/Control/Monad/Class/MonadSTM/Internal.hs
index b7ed593c..f1195777 100644
--- a/io-classes/src/Control/Monad/Class/MonadSTM/Internal.hs
+++ b/io-classes/src/Control/Monad/Class/MonadSTM/Internal.hs
@@ -982,7 +982,6 @@ unGetTBQueueDefault (TBQueue rsize read wsize _write _size) a = do
 -- | Default implementation of 'TArray'.
 --
 data TArrayDefault m i e = TArray (Array i (TVar m e))
-  deriving Typeable
 
 deriving instance (Eq (TVar m e), Ix i) => Eq (TArrayDefault m i e)