Middle drawer for ReadCompose: a fold ∘ partial inner that stays in the fold's container. Below the total cell so a carrier with both an Accessor and a PartialAccessor takes the total read; above the List fallback so a container with a FunctorFilter keeps its type.
Anything foldable ∘ anything foldable → optics.ForgetFold over List. Fires only when no total/partial instance applies, i.e. at least one side is genuinely multi-focus (MultiFocus[F] / Forget[F]).
Anything foldable ∘ anything foldable → optics.ForgetFold over List. Fires only when no total/partial instance applies, i.e. at least one side is genuinely multi-focus (MultiFocus[F] / Forget[F]).
Fold[F] ∘ partial → optics.ForgetFold over the same F: FunctorFilter.mapFilter the inner getOption over the outer's foci, so an inner miss is F's own empty (None, an empty List, an error-carrying result's "empty value"). @group Instances
Fold[F] ∘ partial → optics.ForgetFold over the same F: FunctorFilter.mapFilter the inner getOption over the outer's foci, so an inner miss is F's own empty (None, an empty List, an error-carrying result's "empty value"). @group Instances