val components =
  (f : (A, B, C) => IO[D])
  :: (g : (A, B, D) => IO[E])
  :: (h : A => B)
  :: (j : A => C)
  :: HNil

val context = A :: HNil

val constraints = Before[B, C] :: HNil

for {
  (A, B, C, D) <- solve[(A, B, C, D)](components, context)
  ...
}