diff --git a/src/GM.hs b/src/GM.hs
index 9f3a27b..dbf4718 100644
--- a/src/GM.hs
+++ b/src/GM.hs
@@ -701,12 +701,12 @@ buildInitialHeap (Program ss) = mapAccumL allocateSc mempty compiledScs
                 compileBinder (_ := v, a) = compileC g' v <> [Update a]
 
         -- special cases for prim functions; essentially inlining
-        compileE g ("negate#" :$ a) = compileE g a <>                 [Neg]
-        compileE g ("+#" :$ a :$ b) = compileE g a <> compileE g b <> [Add]
-        compileE g ("-#" :$ a :$ b) = compileE g a <> compileE g b <> [Sub]
-        compileE g ("*#" :$ a :$ b) = compileE g a <> compileE g b <> [Mul]
-        compileE g ("/#" :$ a :$ b) = compileE g a <> compileE g b <> [Div]
-        compileE g ("==#" :$ a :$ b) = compileE g a <> compileE g b <> [Equals]
+        compileE g ("negate#" :$ a)  = compileE g a <>                 [Neg]
+        compileE g ("+#" :$ a :$ b)  = compileE g b <> compileE g a <> [Add]
+        compileE g ("-#" :$ a :$ b)  = compileE g b <> compileE g a <> [Sub]
+        compileE g ("*#" :$ a :$ b)  = compileE g b <> compileE g a <> [Mul]
+        compileE g ("/#" :$ a :$ b)  = compileE g b <> compileE g a <> [Div]
+        compileE g ("==#" :$ a :$ b) = compileE g b <> compileE g a <> [Equals]
 
         compileE g (Case e as) = compileE g e <> [CaseJump (compileD g as)]
 
diff --git a/tst/Arith.hs b/tst/Arith.hs
index da55be1..b6c3a2f 100644
--- a/tst/Arith.hs
+++ b/tst/Arith.hs
@@ -35,7 +35,7 @@ instance Arbitrary ArithExpr where
             gen :: Int -> Gen ArithExpr
             gen n
                 | n > 0 = oneof
-                    -- i don't feel like dealing with zero at the moment
+                    -- i don't feel like dealing with division at the moment
                     [ IntA <$> int
                     , NegateA <$> arbitrary
                     -- , IdA <$> arbitrary
@@ -47,7 +47,8 @@ instance Arbitrary ArithExpr where
                 where
                     b f = liftA2 f s s
                     s = gen (n `div` 2)
-                    int = chooseInt (minBound,maxBound)
+                    -- int = chooseInt (minBound,maxBound)
+                    int = chooseInt (-500,500)
 
 prop_ArithExprEqCoreExpr :: ArithExpr -> Bool
 prop_ArithExprEqCoreExpr e = arithResult `eq1` coreResult
@@ -55,23 +56,23 @@ prop_ArithExprEqCoreExpr e = arithResult `eq1` coreResult
         arithResult = Just (evalA e)
         coreResult  = evalCore (toCore e)
 
-toCore :: ArithExpr -> Program
+toCore :: ArithExpr -> Program'
 toCore expr = Program
         [ ScDef "id" ["x"] $ Var "x"
         , ScDef "main" [] $ go expr
         ]
     where
-        go :: ArithExpr -> Expr
-        go (IntA n)    = IntE n
+        go :: ArithExpr -> Expr'
+        go (IntA n)    = LitE (IntL n)
         go (NegateA e) = "negate#" :$ go e
         go (IdA e)     = "id" :$ go e
-        go (a :+ b)  = f "+#" a b
-        go (a :- b)  = f "-#" a b
-        go (a :* b)  = f "*#" a b
+        go (a :+ b)    = f "+#" a b
+        go (a :- b)    = f "-#" a b
+        go (a :* b)    = f "*#" a b
 
         f n a b = n :$ go a :$ go b
 
-evalCore :: Program -> Maybe Int
+evalCore :: Program' -> Maybe Int
 evalCore p = do
     a <- fst <$> evalProg p
     case a of