a.cs

abstract class X
{
    public abstract T Get<T>();
    public object P { get { return this.Get<Object>(); } }
}

class X<T> : X
{
    public override T Get<T>() { return default(T); }
    public T Get() { return this.Get<T>(); }
    public new T P { get { return this.Get(); } }
}