diff --git a/src/compiler/GF/Compile/Compute/Predef.hs b/src/compiler/GF/Compile/Compute/Predef.hs
index b9e23d424..58b9b3447 100644
--- a/src/compiler/GF/Compile/Compute/Predef.hs
+++ b/src/compiler/GF/Compile/Compute/Predef.hs
@@ -28,8 +28,8 @@ instance Predef Int where
 instance Predef Bool where
   toValue = boolV
   fromValue v = case v of
-    VCApp (cPredef,cPTrue) [] -> return True
-    VCApp (cPredef,cPFalse) [] -> return False
+    VCApp (mn,i) [] | mn == cPredef && i == cPTrue -> return True
+    VCApp (mn,i) [] | mn == cPredef && i == cPFalse -> return False
     _ -> verror "Bool" v
 
 instance Predef String where