/// <summary> /// Equality test /// </summary> public bool Equals(Seq <A> rhs) => !ReferenceEquals(rhs, null) && this.seq == null && rhs.seq == null && this.Count == rhs.Count && this.GetHashCode() == rhs.GetHashCode() && Enumerable.SequenceEqual(this, rhs) ? true : Enumerable.SequenceEqual(this, rhs);
public static int hash <A>(Seq <A> xs) => xs.GetHashCode();