∀ {α : Type u_1} {β : α → Type u_2} (size : ℕ) (k : α) (v : β k) (l r : Std.DTreeMap.Internal.Impl α β) (size_1 : ℕ)
  (k_1 : α) (v_1 : β k_1) (l_1 r_1 : Std.DTreeMap.Internal.Impl α β)
  (h : r = Std.DTreeMap.Internal.Impl.inner size_1 k_1 v_1 l_1 r_1),
  (invImage (fun x => x) sizeOfWFRel).1 r
    (Std.DTreeMap.Internal.Impl.inner size k v l
      (namedPattern r (Std.DTreeMap.Internal.Impl.inner size_1 k_1 v_1 l_1 r_1) h))