diff --git a/common/TestUtil.hs b/common/TestUtil.hs
index 521281c..174111d 100644
--- a/common/TestUtil.hs
+++ b/common/TestUtil.hs
@@ -354,6 +354,7 @@ data ExprHelper =
   | Var String
   | DirVar A.Direction String
   | Lit A.Expression
+  | EHTrue
 
 buildExprPattern :: ExprHelper -> Pattern
 buildExprPattern (Dy lhs op rhs) = tag4 A.Dyadic DontCare op (buildExprPattern lhs) (buildExprPattern rhs)
@@ -362,6 +363,7 @@ buildExprPattern (Cast ty rhs) = tag4 A.Conversion DontCare A.DefaultConversion
 buildExprPattern (Var n) = tag2 A.ExprVariable DontCare $ variablePattern n
 buildExprPattern (DirVar dir n) = tag2 A.ExprVariable DontCare $ (stopCaringPattern m $ tag3 A.DirectedVariable DontCare dir $ variablePattern n)
 buildExprPattern (Lit e) = (stopCaringPattern m) $ mkPattern e
+buildExprPattern EHTrue = tag1 A.True DontCare
 
 buildExpr :: ExprHelper -> A.Expression
 buildExpr (Dy lhs op rhs) = A.Dyadic m op (buildExpr lhs) (buildExpr rhs)
@@ -370,6 +372,7 @@ buildExpr (Cast ty rhs) = A.Conversion m A.DefaultConversion ty (buildExpr rhs)
 buildExpr (Var n) = A.ExprVariable m $ variable n
 buildExpr (DirVar dir n) = A.ExprVariable m $ (A.DirectedVariable m dir $ variable n)
 buildExpr (Lit e) = e
+buildExpr EHTrue = A.True m
 
 -- | A simple definition of a variable
 simpleDef :: String -> A.SpecType -> A.NameDef
diff --git a/frontends/RainTypes.hs b/frontends/RainTypes.hs
index cc78b1a..de2a830 100644
--- a/frontends/RainTypes.hs
+++ b/frontends/RainTypes.hs
@@ -232,3 +232,21 @@ checkAssignmentTypes = everywhereASTM checkAssignment
     checkAssignment (A.Assign {}) = dieInternal "Rain checker found occam-style assignment"
     checkAssignment st = return st
 
+-- | Checks the types in if and while conditionals
+checkConditionalTypes :: Data t => t -> PassM t
+checkConditionalTypes t = (everywhereASTM checkWhile t) >>= (everywhereASTM checkIf)
+  where
+    checkWhile :: A.Process -> PassM A.Process
+    checkWhile w@(A.While m exp _)
+      = do t <- typeOfExpression exp
+           if (t == A.Bool)
+             then return w
+             else dieP m "Expression in while conditional must be of boolean type"
+    checkWhile p = return p
+    
+    checkIf :: A.Choice -> PassM A.Choice
+    checkIf c@(A.Choice m exp _)
+      = do t <- typeOfExpression exp
+           if (t == A.Bool)
+             then return c
+             else dieP m "Expression in if conditional must be of boolean type"
diff --git a/frontends/RainTypesTest.hs b/frontends/RainTypesTest.hs
index 4c776cc..cc104e1 100644
--- a/frontends/RainTypesTest.hs
+++ b/frontends/RainTypesTest.hs
@@ -167,7 +167,9 @@ checkExpressionTest = TestList
   ,passAssignSame 3002 "b" (Var "b")
   ,passAssignSame 3003 "x" $ Dy (Var "x") A.Plus (Var "x")
   ,passAssignSame 3004 "b" $ Dy (Var "x8") A.Eq (Var "x8")
-  ,passAssignSame 3004 "x" $ Mon A.MonadicMinus (Var "x")
+  ,passAssignSame 3005 "x" $ Mon A.MonadicMinus (Var "x")
+  ,passAssignSame 3006 "x8" $ int A.Int8 0
+  ,passAssignSame 3007 "b" EHTrue
 
   ,passAssign 3100 "x" (Cast A.Int64 $ Var "xu8") (Var "xu8")
   ,failAssign 3101 "xu8" (Var "x")
@@ -175,6 +177,18 @@ checkExpressionTest = TestList
   ,failAssign 3103 "b" (Var "x")
   ,failAssign 3104 "x8" (Var "xu8")
   ,failAssign 3105 "xu8" (Var "x8")
+  ,passAssign 3106 "x" (Cast A.Int64 $ int A.Int8 0) (int A.Int8 0)
+  
+  --Conditionals:
+  ,passWhileIfSame 4000 $ Var "b"
+  ,passWhileIfSame 4001 $ Mon A.MonadicNot $ Var "b"
+  ,passWhileIfSame 4002 $ Dy (Var "x") A.Eq (Var "x")
+  ,passWhileIfSame 4003 $ EHTrue 
+  
+  ,failWhileIf 4100 $ Var "x"
+  ,failWhileIf 4101 $ Dy (Var "x") A.Plus (Var "x")
+  
+  
  ]
  where
   passAssign :: Int -> String -> ExprHelper -> ExprHelper -> Test
@@ -193,6 +207,33 @@ checkExpressionTest = TestList
   
   failAssign :: Int -> String -> ExprHelper -> Test
   failAssign n lhs src = TestCase $ testPassShouldFail ("checkExpressionTest " ++ show n) (checkAssignmentTypes $ A.Assign m [variable lhs] $ A.ExpressionList m [buildExpr src]) state
+  
+  passWhileIfSame :: Int -> ExprHelper -> Test
+  passWhileIfSame n e = passWhileIf n e e
+  
+  passWhileIf :: Int -> ExprHelper -> ExprHelper -> Test
+  passWhileIf n exp src = TestList
+    [
+      TestCase $ testPass ("checkExpressionTest/if " ++ show n) 
+        (tag2 A.If DontCare $ tag2 A.OnlyC DontCare $ tag3 A.Choice DontCare (buildExprPattern exp) (tag1 A.Skip DontCare))
+        (checkConditionalTypes $ A.If m $ A.OnlyC m $ A.Choice m (buildExpr src) (A.Skip m))
+        state
+      ,TestCase $ testPass ("checkExpressionTest/while " ++ show n)
+        (tag3 A.While DontCare (buildExprPattern exp) (tag1 A.Skip DontCare))
+        (checkConditionalTypes $ A.While m (buildExpr src) (A.Skip m))
+        state
+    ]
+ 
+  failWhileIf :: Int -> ExprHelper -> Test
+  failWhileIf n src = TestList
+    [
+      TestCase $ testPassShouldFail ("checkExpressionTest/if " ++ show n) 
+        (checkConditionalTypes $ A.If m $ A.OnlyC m $ A.Choice m (buildExpr src) (A.Skip m))
+        state
+      ,TestCase $ testPassShouldFail ("checkExpressionTest/while " ++ show n)
+        (checkConditionalTypes $ A.While m (buildExpr src) (A.Skip m))
+        state
+    ]
  
   passSame :: Int -> A.Type -> ExprHelper -> Test
   passSame n t e = pass n t e e