void Main()
{
  (new Weird() == null).Dump();
  (new Weird().Equals(null)).Dump();
  IsNull(new Weird()).Dump();
}

bool IsNull<T>(T t)
{
  if (t is null)
  {
    return true;
  }
  return false;
}

class Weird : IEquatable<Weird>
{
  public bool Equals(Weird other) => true;

  public override bool Equals(object obj)
  {
    return obj is Weird other && Equals(other);
  }

  public override int GetHashCode() => 0;
  public static bool operator ==(Weird left, Weird right) => left.Equals(right);
  public static bool operator !=(Weird left, Weird right) => !left.Equals(right);
}