{α : Type u} →
  {β : α → Type v} →
    [inst : BEq α] →
      [LawfulBEq α] →
        [inst_2 : Hashable α] →
          [inst_3 : (k : α) → BEq (β k)] →
            [∀ (k : α), LawfulBEq (β k)] → (m₁ m₂ : Std.DHashMap α β) → Decidable (m₁.Equiv m₂)