Compiled model has invalid using directive when model is not in a namespace

[ajcvickers]

Generated code:

// <auto-generated />
using ;
using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.EntityFrameworkCore.Metadata;

// ...

Repro:

public class Blog
{
    public int Id { get; set; }
}

public class SomeDbContext : DbContext
{
    private static ILoggerFactory ContextLoggerFactory
        => LoggerFactory.Create(b => b.AddConsole().SetMinimumLevel(LogLevel.Information));

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        => optionsBuilder
            .UseSqlServer(Your.ConnectionString)
            .UseLoggerFactory(ContextLoggerFactory)
            .EnableSensitiveDataLogging();

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Blog>();
    }
}

public class Program
{
    public static void Main()
    {
        using (var context = new SomeDbContext())
        {
            context.Database.EnsureDeleted();
            context.Database.EnsureCreated();
        }
    }
}