Provide a title on a value. If you can title polymorphically, please instantiate Title_f instead of Title. Then you'll automatically get a Title for each type instance, thanks to this rule.

   instance Title_f f => Title (f a) where title = title_f

To handle ambiguity for types like ([] Char) -- aka String, this module is compiled with OverlappingInstances and UndecidableInstances. The more specific instance (yours) wins.

In defining your instance, you might want to use the String instance, e.g., title ttl "".