diff --git a/site.hs b/site.hs
index 31ac7ec..800c37e 100644
--- a/site.hs
+++ b/site.hs
@@ -127,9 +127,10 @@ processLink base l = do
 pageFilename :: FilePath -> Site FilePath
 pageFilename p = indexFilename $ "page" </> p
 
+checkedSubstitute :: Mu.Template -> Y.Value -> IO T.Text
 checkedSubstitute t v = do
   let (es, txt) = Mu.checkedSubstitute t v
-  io $ traverse_ (putStrLn . ("Error: " ++) . show) es
+  traverse_ (putStrLn . ("Error: " ++) . show) es
   --null es `unless` error "template substitution problems"
   pure txt