completed implicit type casters for reference_wrapper
diff --git a/example/issues.ref b/example/issues.ref
index 74b34c2..fce7b95 100644
--- a/example/issues.ref
+++ b/example/issues.ref
@@ -2,4 +2,4 @@
 c
 Failed as expected: Tried to call pure virtual function "dispatch"
 Yay..
-[Placeholder[1], Placeholder[2], Placeholder[2]]
+[Placeholder[1], Placeholder[2], Placeholder[3], Placeholder[4]]