If you use the "polymorphic variants" feature with backticks it automatically infers the union. However, most of the time the regular non-polymorphic variants a

If you use the "polymorphic variants" feature with backticks it automatically infers the union. However, most of the time the regular non-polymorphic variants are easier to work with. A good discussion of this can be found in https://dev.realworldocaml.org/variants.html#scrollNav-4 https://dev.realworldocaml.org/variants.html#scrollNav-4