diff --git a/src/Text/Pandoc/Readers/Haddock/Lex.x b/src/Text/Pandoc/Readers/Haddock/Lex.x
index a84204e83..120e96ebf 100644
--- a/src/Text/Pandoc/Readers/Haddock/Lex.x
+++ b/src/Text/Pandoc/Readers/Haddock/Lex.x
@@ -131,7 +131,7 @@ data Token
   | TokExamplePrompt String
   | TokExampleExpression String
   | TokExampleResult String
---  deriving Show
+  deriving Show
 
 tokenPos :: LToken -> (Int, Int)
 tokenPos t = let AlexPn _ line col = snd t in (line, col)