{-| I there’s a conflict, it applies the `combine` function, which can choose to
    discard both values.
-}
let Combine = ./Type

in  λ(a : Type) →
    λ(combine : Combine a) →
    λ(left : Optional a) →
    λ(right : Optional a) →
      merge
        { None = right
        , Some = λ(l : a) → merge { None = Some l, Some = combine l } right
        }
        left