diff --git a/benchmark/benchmark-pandoc.hs b/benchmark/benchmark-pandoc.hs
index 653e12634..9e28dd30f 100644
--- a/benchmark/benchmark-pandoc.hs
+++ b/benchmark/benchmark-pandoc.hs
@@ -35,6 +35,7 @@ normalizeBench doc = [ bench "normalize - with" $ nf (encodeJSON . normalize) do
                      , bench "normalize - without" $ nf encodeJSON doc
                      ]
 
+main :: IO ()
 main = do
   inp <- readDataFile (Just ".") "README"
   let opts = def{ readerSmart = True }