diff --git a/Program/Mighty/Types.hs b/Program/Mighty/Types.hs
--- a/Program/Mighty/Types.hs
+++ b/Program/Mighty/Types.hs
@@ -3,7 +3,10 @@
 module Program.Mighty.Types (Natural, naturalToInt) where
 
 #ifdef DHALL
-import GHC.Natural (Natural, naturalToInt)
+import GHC.Natural (Natural, naturalToWord)
+
+naturalToInt :: Natural -> Int
+naturalToInt = fromIntegral . naturalToWord
 #else
 type Natural = Int
 
diff --git a/mighttpd2.cabal b/mighttpd2.cabal
--- a/mighttpd2.cabal
+++ b/mighttpd2.cabal
@@ -1,5 +1,5 @@
 Name:                   mighttpd2
-Version:                4.0.1
+Version:                4.0.2
 Author:                 Kazu Yamamoto <kazu@iij.ad.jp>
 Maintainer:             Kazu Yamamoto <kazu@iij.ad.jp>
 License:                BSD3