diff --git a/Development/Shake/Core.hs b/Development/Shake/Core.hs
--- a/Development/Shake/Core.hs
+++ b/Development/Shake/Core.hs
@@ -69,7 +69,7 @@
     Show key, Typeable key, Eq key, Hashable key, Binary key, NFData key,
     Show value, Typeable value, Eq value, Hashable value, Binary value, NFData value
 #endif
-    ) => Rule key value | key -> value where
+    ) => Rule key value where
 
     -- | Retrieve the @value@ associated with a @key@, if available.
     --
diff --git a/shake.cabal b/shake.cabal
--- a/shake.cabal
+++ b/shake.cabal
@@ -1,7 +1,7 @@
 cabal-version:      >= 1.8
 build-type:         Simple
 name:               shake
-version:            0.9
+version:            0.9.1
 license:            BSD3
 license-file:       LICENSE
 category:           Development
@@ -57,8 +57,8 @@
     html/report.html
 
 source-repository head
-    type:     darcs
-    location: http://community.haskell.org/~ndm/darcs/shake/
+    type:     git
+    location: git://github.com/ndmitchell/shake.git
 
 flag testprog
     default: False