Why is Field not sealed?

[kubukoz]

Hi! I was trying to write a utility for "nesting" a Field[A, B] inside a structure that contains an A - sort of a contramap thing. I noticed Field isn't sealed - is there any specific reason? It seems like the implementation relies on Required/Optional being the only values.

[kubukoz]

In general what I'm actually trying to provide is this:

def nestFieldK[A, S](
    f: S => A
  ): Field[A, *] ~> Field[S, *]

if it makes sense, I'd happily add it here, along with a contramap for fields that this would use underneath.

[SystemFw]

Obscenely late for an answer, but it's sealed now