∀ {α : Type u} {β : α → Type v} (k : α) (v : β k) (r : Std.DTreeMap.Internal.Impl α β) (hr : r.Balanced)
  (hl_2 : Std.DTreeMap.Internal.Impl.leaf.Balanced)
  (hlr_2 : Std.DTreeMap.Internal.Impl.BalancedAtRoot Std.DTreeMap.Internal.Impl.leaf.size r.size),
  Std.DTreeMap.Internal.Impl.minView k v Std.DTreeMap.Internal.Impl.leaf r hl_2 hr hlr_2 =
    { k := k, v := v, tree := { impl := r, balanced_impl := hr, size_impl := ⋯ } }