diff --git a/happstack-static-routing.cabal b/happstack-static-routing.cabal
--- a/happstack-static-routing.cabal
+++ b/happstack-static-routing.cabal
@@ -1,5 +1,5 @@
 Name:                happstack-static-routing
-Version:             0.3
+Version:             0.3.1
 Synopsis: Support for static URL routing with overlap detection for Happstack.
 
 Description: If you have a large routing table in Happstack and want
diff --git a/src/Happstack/StaticRouting/Internal.hs b/src/Happstack/StaticRouting/Internal.hs
--- a/src/Happstack/StaticRouting/Internal.hs
+++ b/src/Happstack/StaticRouting/Internal.hs
@@ -1,6 +1,6 @@
 {-# LANGUAGE OverlappingInstances, FunctionalDependencies, ScopedTypeVariables,
     MultiParamTypeClasses, FlexibleInstances, UndecidableInstances,
-    FlexibleContexts #-}
+    FlexibleContexts, DeriveFunctor #-}
 {-# OPTIONS_HADDOCK hide #-}
 
 module Happstack.StaticRouting.Internal where
@@ -23,6 +23,7 @@
   | Handler EndSegment a
   | Param String (Route a)
   | Choice [Route a]
+  deriving Functor
 
 -- For backwards compatibility with GHC 6.12
 handler :: EndSegment -> a -> Route a