diff --git a/mono-traversable.cabal b/mono-traversable.cabal
--- a/mono-traversable.cabal
+++ b/mono-traversable.cabal
@@ -1,5 +1,5 @@
 name:                mono-traversable
-version:             0.6.0
+version:             0.6.0.1
 synopsis:            Type classes for mapping, folding, and traversing monomorphic containers
 description:         Monomorphic variants of the Functor, Foldable, and Traversable typeclasses. Contains even more experimental code for abstracting containers and sequences.
 homepage:            https://github.com/snoyberg/mono-traversable
diff --git a/test/Spec.hs b/test/Spec.hs
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -30,6 +30,7 @@
 import qualified Data.IntSet as IntSet
 import Control.Arrow (first, second)
 import qualified Control.Foldl as Foldl
+import Data.Int (Int64)
 
 main :: IO ()
 main = hspec $ do
@@ -41,13 +42,15 @@
     describe "osum" $ do
         it "list" $ do
             let x = 1
-                y = 10000000 :: Int
+                -- explicitly using Int64 to avoid overflow issues, see:
+                -- https://github.com/snoyberg/mono-traversable/issues/29
+                y = 10000000 :: Int64
                 list = [x..y]
             osum list `shouldBe` ((x + y) * (y - x + 1) `div` 2)
     describe "oproduct" $ do
         it "list" $ do
             let x = 1
-                y = 10000000 :: Int
+                y = 10000000 :: Int64
                 list = [x..y]
                 fact n =
                     go 1 1