diff --git a/src/Data/Output.hs b/src/Data/Output.hs
index 19307c4d8..9ce22da9b 100644
--- a/src/Data/Output.hs
+++ b/src/Data/Output.hs
@@ -4,3 +4,6 @@ import Prologue
 
 class Monoid o => Output o where
   toOutput :: o -> ByteString
+
+instance Output ByteString where
+  toOutput s = s