diff --git a/constantine/word_types.nim b/constantine/word_types.nim
index 43cb2b6..4eb0187 100644
--- a/constantine/word_types.nim
+++ b/constantine/word_types.nim
@@ -15,11 +15,11 @@ type
     ## by conditional branches, we don't use booleans.
     ## We use an int to prevent compiler "optimization" and introduction of branches
 
-func ctrue*(T: type(Ct)): auto {.inline.}=
-  (CTBool[T])(true)
+func ctrue*(T: typedesc[BaseUint]): auto {.inline.}=
+  (CTBool[Ct[T]])(true)
 
-func cfalse*(T: type(Ct)): auto {.inline.}=
-  (CTBool[T])(false)
+func cfalse*(T: typedesc[BaseUint]): auto {.inline.}=
+  (CTBool[Ct[T]])(false)
 
 func ct*[T: BaseUint](x: T): Ct[T] {.inline.}=
   (Ct[T])(x)