using System;
 
public abstract class Response { }
public abstract class Request<T> where T : Response { }
public class LoginResponse : Response { }
public class LoginRequest : Request<LoginResponse> { }
 
public class Program
{
    static void Main(string[] args)
    {
        LoginRequest login = new LoginRequest();
 
 
        /* Error: Cannot implicitly convert type 'LoginRequest' to 'Request' */
        Request<Response> castTest = login;
 
 
        /* No Error */
        Request<LoginResponse> castTest2 = login;
    }
}

据我所知,LoginRequest类是Request< Response>因为是继承自Request< T>和LoginResponse继承自Response,所以任何人都可以告诉我为什么我得到编译器错误？

注意：我也试过一个明确的演员