diff --git a/Data/Semigroup/Union.hs b/Data/Semigroup/Union.hs
--- a/Data/Semigroup/Union.hs
+++ b/Data/Semigroup/Union.hs
@@ -62,10 +62,10 @@
 instance HasUnion0 (IntMap a) where
   empty = IntMap.empty
 
-instance Eq k => HasUnion (HashMap k a) where
+instance (Eq k, Hashable k) => HasUnion (HashMap k a) where
   union = HashMap.union
 
-instance Eq k => HasUnion0 (HashMap k a) where
+instance (Eq k, Hashable k) => HasUnion0 (HashMap k a) where
   empty = HashMap.empty
 
 instance Ord k => HasUnion (Map k a) where
diff --git a/reducers.cabal b/reducers.cabal
--- a/reducers.cabal
+++ b/reducers.cabal
@@ -1,6 +1,6 @@
 name:          reducers
 category:      Data, Math, Numerical, Semigroups
-version:       0.1.8
+version:       0.1.9
 license:       BSD3
 cabal-version: >= 1.6
 license-file:  LICENSE
@@ -32,7 +32,7 @@
     hashable               >= 1.1.2.1  && < 1.2,
     text                   >= 0.11.1.5 && < 0.12,
     parallel               >= 3.2      && < 3.3,
-    unordered-containers   >= 0.1.4    && < 0.2,
+    unordered-containers   >= 0.1.4    && < 0.3,
     semigroups             >= 0.8      && < 0.9,
     semigroupoids          >= 1.2.6.1  && < 1.3,
     comonad                >= 1.1.1.1  && < 1.2,