diff --git a/src/bind.inc.php b/src/bind.inc.php
index b09ae5a..2856783 100644
--- a/src/bind.inc.php
+++ b/src/bind.inc.php
@@ -313,7 +313,7 @@ function bhl_type_ref(\mtgType $type = null)
     $is_coro = $type->hasToken("bhl_coroutine");
     $str = '';
     $str .= "types.TFunc(".($is_coro?"true":"false").", ";
-    $str .= $type->getReturnType() ? bhl_type_ref($type->getReturnType()) : bhl_type_ref(null);
+    $str .= ($type->getReturnType() ? bhl_type_ref($type->getReturnType()) : bhl_type_ref(null)) . ",";
     foreach($type->getArgs() as $arg)
       $str .= bhl_type_ref($arg->getType()) . ",";
     $str = rtrim($str, ',');