ASP.NET Core - custom AspNetCore.Identity implementation not working

I'm building a completely custom AspNetCore.Identity Implementation because I want TKey to be System.Guid across the board. With respect, I have derived types for...

Role : IdentityRole<Guid, UserRole, RoleClaim>
RoleClaim : IdentityRoleClaim<Guid>
User : IdentityUser<Guid, UserClaim, UserRole, UserLogin>
UserClaim : IdentityUserClaim<Guid>
UserLogin : IdentityUserLogin<Guid>
UserRole : IdentityUserRole<Guid>
UserToken : IdentityUserToken<Guid>
ApplicationDbContext : IdentityDbContext<User, Role, Guid, UserClaim, UserRole, UserLogin, RoleClaim, UserToken>
ApplicationRoleManager : RoleManager<Role>
ApplicationRoleStore : RoleStore<Role, ApplicationDbContext, Guid, UserRole, RoleClaim>
ApplicationSignInManager : SignInManager<User>
ApplicationUserManager : UserManager<User>
**ApplicationUserStore** : UserStore<User, Role, ApplicationDbContext, Guid, UserClaim, UserRole, UserLogin, UserToken>

ApplicationUserStore is the problem child!

Implementation

namespace NewCo.Identity
{
    using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
    using System;

    public sealed class Role : IdentityRole<Guid, UserRole, RoleClaim>
    {
    }
}

namespace NewCo.Identity
{
    using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
    using System;

    public sealed class UserRole : IdentityUserRole<Guid>
    {
    }
}

namespace NewCo.Identity
{
    using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
    using System;

    public sealed class RoleClaim : IdentityRoleClaim<Guid>
    {
    }
}

// The problem is here...

namespace NewCo.Identity
{
    using Microsoft.AspNetCore.Identity;
    using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
    using System;
    using System.Security.Claims;

    public sealed class ApplicationUserStore : UserStore<User, Role, ApplicationDbContext, Guid, UserClaim, UserRole, UserLogin, UserToken>
    {
    }
}

Error

The type 'NewCo.Identity.Role' cannot be used as type parameter 'TRole' in the generic type or method 'UserStore'. There is no implicit reference conversion from 'NewCo.Identity.Role' to 'Microsoft.AspNetCore.Identity.EntityFrameworkCore.IdentityRole>'.

As far as I can see, unless this is some (co/contra/in)variance issue, all the code checks out...what did I get wrong?

Solution

Your ApplicationUserStore needs the RoleClaim at the end too (don't forget to update the related NuGet packages, otherwise you can't use these new additions):

    ApplicationUserStore : UserStore<
            User, Role, ApplicationDbContext, 
            Guid, UserClaim, UserRole, 
            UserLogin, UserToken, RoleClaim>

Plus your ApplicationRoleStore should provide how to create the RoleClaim,

protected override RoleClaim CreateRoleClaim(Role role, Claim claim)
{
    return new RoleClaim
    {
        RoleId = role.Id,
        ClaimType = claim.Type,
        ClaimValue = claim.Value
    };
}

And also the ApplicationUserStore should provide these mappings too:

protected override UserClaim CreateUserClaim(User user, Claim claim)
{
    var userClaim = new UserClaim { UserId = user.Id };
    userClaim.InitializeFromClaim(claim);
    return userClaim;
}

protected override UserLogin CreateUserLogin(User user, UserLoginInfo login)
{
    return new UserLogin
    {
        UserId = user.Id,
        ProviderKey = login.ProviderKey,
        LoginProvider = login.LoginProvider,
        ProviderDisplayName = login.ProviderDisplayName
    };
}

protected override UserRole CreateUserRole(User user, Role role)
{
    return new UserRole
    {
        UserId = user.Id,
        RoleId = role.Id
    };
}

protected override UserToken CreateUserToken(User user, string loginProvider, string name, string value)
{
    return new UserToken
    {
        UserId = user.Id,
        LoginProvider = loginProvider,
        Name = name,
        Value = value
    };
}

Then redirect built-in services to your custom services:

services.AddScoped<UserStore<User, Role, ApplicationDbContext, int, UserClaim, UserRole, UserLogin, UserToken, RoleClaim>, ApplicationUserStore>();
services.AddScoped<UserManager<User>, ApplicationUserManager>();
services.AddScoped<RoleManager<Role>, ApplicationRoleManager>();
services.AddScoped<SignInManager<User>, ApplicationSignInManager>();
services.AddScoped<RoleStore<Role, ApplicationDbContext, int, UserRole, RoleClaim>, ApplicationRoleStore>();
services.AddScoped<IEmailSender, AuthMessageSender>();
services.AddScoped<ISmsSender, AuthMessageSender>();

now introduce your custom services:

services.AddIdentity<User, Role>(identityOptions =>
            {
             // ...
            }).AddUserStore<ApplicationUserStore>()
              .AddUserManager<ApplicationUserManager>()
              .AddRoleStore<ApplicationRoleStore>()
              .AddRoleManager<ApplicationRoleManager>()
              .AddSignInManager<ApplicationSignInManager>()
              // You **cannot** use .AddEntityFrameworkStores() when you customize everything
              //.AddEntityFrameworkStores<ApplicationDbContext, int>()
              .AddDefaultTokenProviders();