What is the kind of Void?

Question

Seeing as the type of Void is uninhabited, can it be regarded as a type \"constructor\"? Or is this just a quick \"hack\" to be able to safely disregard / disable f

Answer 1

It's a type of kind * just like Int, Bool or (). It just happens to have 0 values instead of 1 or 2 or more.

It's not a hack but rather a fundamental part of Haskell's type system. It plays the role of 0 to ()'s 1 and, if we look at types as propositions, Void corresponds to the proposition "false". It's also an identity to sum types (Either) just like () is an identity to product types: Either a Void is isomorphic to a.

In practice, it often acts as a dual of (); the best example of this I've seen is in pipes where () is used to tag things that don't take inputs and Void (named X) is used to tag things that don't produce outputs. (See Appendix:Types in the tutorial.)

It is a way to mark things as impossible or missing, but it is by no means a hack.