假设:
sealed trait F
sealed trait K extends F
case object K1 extends K
sealed trait L extends F
case object L1 extends L
使用上面的层次结构,我如何定义一个函数,该函数在编译时具有类型A
的列表,该列表全部为K
或L
,即超类型必须是K
或L
,而不是F
?
示例:
由于列表的超类型为f(List(K1, K1))
, K
会编译
但
f(List(K1, L1))
不会,因为列表的超类型是F
答案 0 :(得分:1)
你可以从Miles Sabin的答案开始Enforce type difference并改编:
public void ConfigureAuth(IAppBuilder app)
{
// Configure the db context, user manager and signin manager to use a single instance per request
app.CreatePerOwinContext(ApplicationDbContext.Create);
app.CreatePerOwinContext<ApplicationUserManager>(ApplicationUserManager.Create);
app.CreatePerOwinContext<ApplicationSignInManager>(ApplicationSignInManager.Create);
// Enable the application to use a cookie to store information for the signed in user
// and to use a cookie to temporarily store information about a user logging in with a third party login provider
// Configure the sign in cookie
app.UseCookieAuthentication(new CookieAuthenticationOptions
{
AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
LoginPath = new PathString("/Account/Login"),
LogoutPath = new PathString("/Account/LogOff"),
Provider = new CookieAuthenticationProvider
{
// Enables the application to validate the security stamp when the user logs in.
// This is a security feature which is used when you change a password or add an external login to your account.
OnValidateIdentity = SecurityStampValidator.OnValidateIdentity<ApplicationUserManager, ApplicationUser>(
validateInterval: TimeSpan.FromMinutes(0),
regenerateIdentity: (manager, user) => user.GenerateUserIdentityAsync(manager))
},
});
//app.UseExternalSignInCookie(DefaultAuthenticationTypes.ExternalCookie);
// these two lines of code are needed if you are using any of the external authentication middleware
app.Properties["Microsoft.Owin.Security.Constants.DefaultSignInAsAuthenticationType"] = "ExternalCookie";
app.UseCookieAuthentication(new CookieAuthenticationOptions
{
AuthenticationType = "ExternalCookie",
AuthenticationMode = Microsoft.Owin.Security.AuthenticationMode.Passive,
});
// Enables the application to temporarily store user information when they are verifying the second factor in the two-factor authentication process.
app.UseTwoFactorSignInCookie(DefaultAuthenticationTypes.TwoFactorCookie, TimeSpan.FromMinutes(5));
// Enables the application to remember the second login verification factor such as phone or email.
// Once you check this option, your second step of verification during the login process will be remembered on the device where you logged in from.
// This is similar to the RememberMe option when you log in.
app.UseTwoFactorRememberBrowserCookie(DefaultAuthenticationTypes.TwoFactorRememberBrowserCookie);
}