We can regard any functor as dependently indexed, with specified fixed index.
record FixDepIndex : i -> (Type -> Type) -> (i -> Type) -> TypeWithDepIndex : f (a x) -> FixDepIndex x f a.unIndex : FixDepIndex x f a -> f (a x)Filterable f => DepFilterable i (FixDepIndex x f)Foldable f => DepFoldable i (FixDepIndex x f)Functor f => DepFunctor i (FixDepIndex x f)Traversable f => DepTraversable i (FixDepIndex x f)Witherable f => DepWitherable i (FixDepIndex x f).unIndex : FixDepIndex x f a -> f (a x)unIndex : FixDepIndex x f a -> f (a x)