diff --git a/frontends/OccamTypes.hs b/frontends/OccamTypes.hs
index 6399c27..2a2f887 100644
--- a/frontends/OccamTypes.hs
+++ b/frontends/OccamTypes.hs
@@ -733,7 +733,7 @@ inferTypes = occamOnlyPass "Infer types"
     doReplicator :: Transform A.Replicator
     doReplicator rep
         = case rep of
-            A.For _ _ _ -> inTypeContext (Just A.Int) $ descend rep
+            A.For _ _ _ _ -> inTypeContext (Just A.Int) $ descend rep
             A.ForEach _ _ -> noTypeContext $ descend rep
 
     doAlternative :: Transform A.Alternative
@@ -1267,9 +1267,10 @@ checkSpecTypes = checkDepthM doSpecType
               checkRetypes m fromT t
               checkValAM m am
               checkAbbrev m A.ValAbbrev am
-    doSpecType (A.Rep _ (A.For _ start count))
+    doSpecType (A.Rep _ (A.For _ start count step))
         =  do checkExpressionInt start
               checkExpressionInt count
+              checkExpressionInt step
     doSpecType (A.Rep _ (A.ForEach _ e))
         =  do t <- astTypeOf e
               checkSequence (findMeta e) t
diff --git a/frontends/OccamTypesTest.hs b/frontends/OccamTypesTest.hs
index 033ff9c..428c9fb 100644
--- a/frontends/OccamTypesTest.hs
+++ b/frontends/OccamTypesTest.hs
@@ -298,12 +298,13 @@ testOccamTypes = TestList
     , testFail 1186 $ A.Input m tim $ A.InputTimerFor m realE
 
     -- Replicators
-    , testOK   1200 $ testRep i $ A.For m intE intE
-    , testFail 1201 $ testRep i $ A.For m realE intE
-    , testFail 1202 $ testRep i $ A.For m intE realE
+    , testOK   1200 $ testRep i $ A.For m intE intE intE
+    , testFail 1201 $ testRep i $ A.For m realE intE intE
+    , testFail 1202 $ testRep i $ A.For m intE realE intE
     , testOK   1203 $ testRep i $ A.ForEach m twoIntsE
     , testOK   1204 $ testRep i $ A.ForEach m listE
     , testFail 1205 $ testRep i $ A.ForEach m intE
+    , testFail 1206 $ testRep i $ A.For m intE intE realE
 
     -- Choices
     , testOK   1300 $ testChoice $ A.Choice m boolE skip
diff --git a/frontends/RainPasses.hs b/frontends/RainPasses.hs
index 0755a6e..a89a710 100644
--- a/frontends/RainPasses.hs
+++ b/frontends/RainPasses.hs
@@ -191,7 +191,7 @@ transformEachRange = rainOnlyPass "Convert seqeach/pareach loops over ranges int
         =   do -- Need to change the stored abbreviation mode to original:
                modifyName loopVar $ \nd -> nd { A.ndAbbrevMode = A.Original }
                return $ A.Specification mspec loopVar $ A.Rep repMeta $ A.For eachMeta begin
-                 (addOne $ subExprs end begin)
+                 (addOne $ subExprs end begin) (makeConstant eachMeta 1)
     doSpec s = return s
 
 -- | A pass that changes all the Rain range constructor expressions into the more general array constructor expressions
@@ -209,7 +209,7 @@ transformRangeRep = rainOnlyPass "Convert simple Rain range constructors into mo
           =        do A.Specification _ rep _ <- makeNonceVariable "rep_constr" m A.Int A.ValAbbrev
                       let count = addOne $ subExprs end begin
                       return $ A.ExprConstr m $ A.RepConstr m t rep
-                        (A.For m begin count)
+                        (A.For m begin count $ makeConstant m 1)
                           (A.ExprVariable m $ A.Variable m rep)
     doExpression e = return e
 
diff --git a/frontends/RainPassesTest.hs b/frontends/RainPassesTest.hs
index 575c699..b70f2cd 100644
--- a/frontends/RainPassesTest.hs
+++ b/frontends/RainPassesTest.hs
@@ -74,7 +74,7 @@ testEachRangePass0 = TestCase $ testPass "testEachRangePass0" exp transformEachR
                  undefined (intLiteral 0) (intLiteral 9)))))
                (A.Only m (makeSimpleAssign "c" "x"))
     exp = A.Par m A.PlainPar $ A.Spec m (A.Specification m (simpleName "x")
-               $ A.Rep m (A.For m (intLiteral 0) (makeRange 0 9)))
+               $ A.Rep m (A.For m (intLiteral 0) (makeRange 0 9) (intLiteral 1)))
                (A.Only m (makeSimpleAssign "c" "x"))
                
 testEachRangePass1 :: Test
@@ -86,7 +86,7 @@ testEachRangePass1 = TestCase $ testPass "testEachRangePass1" exp transformEachR
                (A.Only m (makeSimpleAssign "c" "x"))
     exp = A.Par m A.PlainPar $ A.Spec m (A.Specification m (simpleName "x")
                $ A.Rep m (A.For m (intLiteral (-5)) (makeRange (-5)
-                 (-2))))
+                 (-2)) (intLiteral 1)))
                (A.Only m (makeSimpleAssign "c" "x"))                            
 
 testEachRangePass2 :: Test
@@ -97,7 +97,7 @@ testEachRangePass2 = TestCase $ testPass "testEachRangePass2" exp transformEachR
                  (intLiteral 6) (intLiteral 6)))))
                (A.Only m (makeSimpleAssign "c" "x"))
     exp = A.Seq m $ A.Spec m (A.Specification m (simpleName "x") $ A.Rep m
-               (A.For m (intLiteral 6) (makeRange 6 6)))
+               (A.For m (intLiteral 6) (makeRange 6 6) (intLiteral 1)))
                (A.Only m (makeSimpleAssign "c" "x"))
                
 testEachRangePass3 :: Test
@@ -108,7 +108,7 @@ testEachRangePass3 = TestCase $ testPass "testEachRangePass3" exp transformEachR
                  (intLiteral 6) (intLiteral 0)))))
                (A.Only m (makeSimpleAssign "c" "x"))
     exp = A.Seq m $ A.Spec m (A.Specification m (simpleName "x") $ A.Rep m
-               (A.For m (intLiteral 6) (makeRange 6 0)))
+               (A.For m (intLiteral 6) (makeRange 6 0) (intLiteral 1)))
                (A.Only m (makeSimpleAssign "c" "x"))               
 
 
@@ -357,7 +357,7 @@ testRangeRepPass0 = TestCase $ testPass "testRangeRepPass0" exp transformRangeRe
   where
     orig = A.ExprConstr m $ A.RangeConstr m A.Byte (intLiteral 0) (intLiteral 1)
     exp = tag2 A.ExprConstr DontCare $ mRepConstr A.Byte ("repIndex"@@DontCare)
-        (mFor (intLiteral 0) (makeRange 0 1))
+        (mFor (intLiteral 0) (makeRange 0 1) (intLiteral 1))
       (tag2 A.ExprVariable DontCare $ tag2 A.Variable DontCare $ "repIndex"@@DontCare)
 
 --TODO consider/test pulling up the definitions of variables involved in return statements in functions