∀ {α : Type u} {r : Std.Roi α} [inst : Std.PRange.UpwardEnumerable α] [inst_1 : Std.PRange.LawfulUpwardEnumerable α]
  [inst_2 : Std.Rxi.IsAlwaysFinite α], r.toArray = #[] ↔ (Std.PRange.succ? r.lower).isNone = true