What is the assumption made in “Learn You a Haskell” when deducing the kind?

Question

This question is not subjective. A very specific verb is used in the referenced book, and I\'d like to understand what the implication of that phrasing is, because I\'m afraid I

Answer 1

In fact, the compiler does assume! But you can ask it not to with the PolyKinds extension. You can read about it in more detail here. With that extension turned on, the kind of Barry will be forall k. (k -> *) -> k -> * -> *.