diff --git a/Data/Interned/IntSet.hs b/Data/Interned/IntSet.hs
--- a/Data/Interned/IntSet.hs
+++ b/Data/Interned/IntSet.hs
@@ -202,9 +202,9 @@
   cache = intSetCache
 
 instance Hashable (Description IntSet) where
-  hash DNil = 0
-  hash (DTip n) = 1 `hashWithSalt` n
-  hash (DBin p m l r) = hash p `hashWithSalt` m `hashWithSalt` l `hashWithSalt` r
+  hashWithSalt s DNil = s `hashWithSalt` (0 :: Int)
+  hashWithSalt s (DTip n) = s `hashWithSalt` (1 :: Int) `hashWithSalt` n
+  hashWithSalt s (DBin p m l r) = s `hashWithSalt` (2 :: Int) `hashWithSalt` p `hashWithSalt` m `hashWithSalt` l `hashWithSalt` r
 
 intSetCache :: Cache IntSet
 intSetCache = mkCache
diff --git a/Data/Interned/Internal/String.hs b/Data/Interned/Internal/String.hs
--- a/Data/Interned/Internal/String.hs
+++ b/Data/Interned/Internal/String.hs
@@ -38,8 +38,8 @@
   unintern = uninternString
 
 instance Hashable (Description InternedString) where
-  hash (Cons c s) = foldl' hashWithSalt (hashWithSalt 0 c) s
-  hash Nil        = 0
+  hashWithSalt s (Cons c cs) = foldl' hashWithSalt (hashWithSalt s c) cs
+  hashWithSalt s Nil         = s `hashWithSalt` (0 :: Int)
 
 stringCache :: Cache InternedString
 stringCache = mkCache
diff --git a/Data/Interned/Internal/Text.hs b/Data/Interned/Internal/Text.hs
--- a/Data/Interned/Internal/Text.hs
+++ b/Data/Interned/Internal/Text.hs
@@ -36,7 +36,7 @@
   unintern (InternedText _ b) = b
 
 instance Hashable (Description InternedText) where
-  hash (DT h) = hash h
+  hashWithSalt s (DT h) = hashWithSalt s h
 
 itCache :: Cache InternedText
 itCache = mkCache
diff --git a/intern.cabal b/intern.cabal
--- a/intern.cabal
+++ b/intern.cabal
@@ -1,6 +1,6 @@
 name:          intern
 category:      Data, Data Structures
-version:       0.9.1
+version:       0.9.1.1
 license:       BSD3
 cabal-version: >= 1.6
 license-file:  LICENSE
@@ -47,7 +47,7 @@
     base                 >= 4 && < 5,
     bytestring           >= 0.9 && < 0.11,
     text                 == 0.11.*,
-    hashable             == 1.1.*,
+    hashable             >= 1.1 && < 1.3,
     unordered-containers >= 0.2.1 && < 0.3,
     array                >= 0.3 && < 0.5