diff --git a/metrics.cabal b/metrics.cabal
--- a/metrics.cabal
+++ b/metrics.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                metrics
-version:             0.4.1.0
+version:             0.4.1.1
 synopsis:            High-performance application metric tracking
 description:
   A port of Coda Hale's excellent metrics library for the JVM
diff --git a/src/Data/Metrics/Reservoir/Uniform.hs b/src/Data/Metrics/Reservoir/Uniform.hs
--- a/src/Data/Metrics/Reservoir/Uniform.hs
+++ b/src/Data/Metrics/Reservoir/Uniform.hs
@@ -5,6 +5,7 @@
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE UndecidableInstances #-}
 -- | A histogram with a uniform reservoir produces quantiles which are valid for the entirely of the histogram’s lifetime.
 -- It will return a median value, for example, which is the median of all the values the histogram has ever been updated with.
 -- It does this by using an algorithm called Vitter’s R), which randomly selects values for the reservoir with linearly-decreasing probability.