diff --git a/include/ruby/internal/value_type.h b/include/ruby/internal/value_type.h
index 977f60a009..557f18813b 100644
--- a/include/ruby/internal/value_type.h
+++ b/include/ruby/internal/value_type.h
@@ -443,7 +443,7 @@ Check_Type(VALUE v, enum ruby_value_type t)
     }
 
   unexpected_type:
-    rb_unexpected_type(v, t);
+    rb_unexpected_type(v, RBIMPL_CAST((int)t));
 }
 
 #endif /* RBIMPL_VALUE_TYPE_H */