Support for WithContext structure promotion added to Context.Companion

[oskin1]

No description provided.

[catostrophe]

I think the priorities are wrong. WithLocal as a more concrete instance should be higher, and WithContext - lower.

Can you write a summon test?

[catostrophe]

Why did you make it an inner class? It could be a concrete high-level class, as we usually do in tofu:

class WithContextContains[F[_], C, A](implicit wc: WithContext[F, C],  field: C Contains A)
  extends WithContext[F, A] {
  private val wa =  wc.extract(field) 
  def functor: Functor[F] = wa.functor
  def context: F[A]       = wa.context
}

And then in trait.

implicit def promoteContextStructure[F[_], A](implicit withContext: WithContext[F, C],
    field: C Contains A
): WithContextContains[F, C, A] =
    new WithContextContains[F, C, A]

[oskin1]

@catostrophe, my bad, we'd better keep style consistent.