@samth While implementing a type system, I ran into a confusing bug, only to discover that I made the mistake of treating forall types as constructors, and it reminded me of you explaining the same issue in Typed Racket.

Indeed, don’t do that!

huh, why shouldn’t that be done?

Type constructors are functions from types to types, whereas a forall type is the type of a function from types to values, which means it isn’t a type constructor at all.

Ahh, gotcha, that makes sense