Migrazione di Auth a Core 2.0: il tipo di entità 'IdentityUserRole 'richiede una chiave primaria da definire

Sto migrando la mia app in ASP.Net Core 2.0.

https://docs.microsoft.com/en-us/aspnet/core/migration/1x-to-2x/identity-2x

Nell'articolo sopra riportato, ha la seguente mappatura:

protected override void OnModelCreating(ModelBuilder builder)
{
    base.OnModelCreating(builder);
    // Customize the ASP.NET Identity model and override the defaults if needed.
    // For example, you can rename the ASP.NET Identity table names and more.
    // Add your customizations after calling base.OnModelCreating(builder);

    builder.Entity<ApplicationUser>()
        .HasMany(e => e.Claims)
        .WithOne()
        .HasForeignKey(e => e.UserId)
        .IsRequired()
        .OnDelete(DeleteBehavior.Cascade);

    builder.Entity<ApplicationUser>()
        .HasMany(e => e.Logins)
        .WithOne()
        .HasForeignKey(e => e.UserId)
        .IsRequired()
        .OnDelete(DeleteBehavior.Cascade);

    builder.Entity<ApplicationUser>()
        .HasMany(e => e.Roles)
        .WithOne()
        .HasForeignKey(e => e.UserId)
        .IsRequired()
        .OnDelete(DeleteBehavior.Cascade);
}

Mi sta bene. Tuttavia, quando corro

dotnet ef migrations add InitialCreate

Ottengo il seguente errore:

Il tipo di entità 'IdentityUserRole' richiede una chiave primaria da definire.

ApplicationUser è definito come segue:

public class ApplicationUser : IdentityUser
{
    /// <summary>
    /// Navigation property for the roles this user belongs to.
    /// </summary>
    public virtual ICollection<IdentityUserRole<int>> Roles { get; } = new List<IdentityUserRole<int>>();

    /// <summary>
    /// Navigation property for the claims this user possesses.
    /// </summary>
    public virtual ICollection<IdentityUserClaim<int>> Claims { get; } = new List<IdentityUserClaim<int>>();

    /// <summary>
    /// Navigation property for this users login accounts.
    /// </summary>
    public virtual ICollection<IdentityUserLogin<int>> Logins { get; } = new List<IdentityUserLogin<int>>();

    public string FullName { get; set; }
}

C'è qualcosa di sbagliato nella mappatura?