Hello!
I am working with TypeReps, and while writing some functions I have
noticed that I could use lenses to simplify them; however, I have stumbled
upon some difficulties.
First I’ll try to clarify which functions I want to write:
* a function for converting TypeRep of, say, `Maybe x` to
`ifL` isn't a legal lens for several reasons.
Lens s t a b generally requires that the types a subsumes b and b subsumes
a, and that s subsumes t and t subsumes s.
Lens s (Maybe t) (Maybe a) b is a huge red flag.
There is an 'illegal prism' provided by lens that is a more principled
version of
