HashSet creation

using System;//from j  av  a2  s  . c  o m
using System.Collections.Generic;

class Program
{
    public static void Main()
    {
        MyComparer myComparer = new MyComparer();
        HashSet<string> allVehicles = new HashSet<string>(myComparer);

        allVehicles.Add("A");
        allVehicles.Add("T");
        allVehicles.Add("B");
    }
}

class MyComparer : EqualityComparer<string>
{
    public override bool Equals(string s1, string s2)
    {
        return s1.Equals(s2, StringComparison.CurrentCultureIgnoreCase);
    }
    public override int GetHashCode(string s)
    {
        return base.GetHashCode();
    }
}