diff --git a/bower.json b/bower.json
index 28a27e5..8bad8b0 100644
--- a/bower.json
+++ b/bower.json
@@ -35,7 +35,7 @@
     "purescript-semirings": "^4.0.0",
     "purescript-tuples": "^4.0.0",
     "purescript-validation": "^3.0.0",
-    "purescript-aff": "^3.0.0",
+    "purescript-aff": "^4.0.0",
     "purescript-control": "^3.0.0",
     "purescript-console": "^3.0.0",
     "purescript-integers": "^3.0.0"
diff --git a/package.json b/package.json
index a6271ca..da76be2 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
   "private": true,
   "scripts": {
     "clean": "rimraf output && rimraf .pulp-cache",
-    "build": "pulp build --censor-lib --strict",
+    "build": "pulp build -- --censor-lib --strict",
     "test": "pulp test"
   },
   "devDependencies": {
diff --git a/src/Routing.purs b/src/Routing.purs
index 128890d..4e0f7bd 100644
--- a/src/Routing.purs
+++ b/src/Routing.purs
@@ -9,17 +9,16 @@ module Routing (
   matchesAff'
   ) where
 
-import Prelude (Unit, unit, pure, const, ($))
-import Control.Monad.Eff (Eff())
-import Control.Monad.Aff (Aff(), makeAff)
-import Data.Maybe (Maybe(..))
+import Control.Monad.Aff (Aff, makeAff, nonCanceler)
+import Control.Monad.Eff (Eff)
 import Data.Either (Either(..), either)
-import Data.Tuple (Tuple(..))
+import Data.Maybe (Maybe(..))
 import Data.String.Regex as R
 import Data.String.Regex.Flags as RF
-
-import Routing.Parser (parse)
+import Data.Tuple (Tuple(..))
+import Prelude (Unit, const, pure, unit, ($), (<$))
 import Routing.Match (Match, runMatch)
+import Routing.Parser (parse)
 
 
 foreign import decodeURIComponent :: String -> String
@@ -53,9 +52,9 @@ matches' decoder routing cb = hashes $ \old new ->
 matchesAff' :: forall e a. (String -> String) ->
                Match a -> Aff e (Tuple (Maybe a) a)
 matchesAff' decoder routing =
-  makeAff \_ k -> do
+  makeAff \k -> nonCanceler <$
     matches' decoder routing \old new ->
-      k $ Tuple old new
+      k $ Right $ Tuple old new
 
 matchesAff :: forall e a. Match a -> Aff e (Tuple (Maybe a) a)
 matchesAff = matchesAff' decodeURIComponent