QueryTypes: using DbQuery inside a defining query of another QueryType produces incorrect SQL - treating the referenced DbQuery as if it were a DbSet

[maumar]

Repro:

    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");

            using (var ctx = new MyContext())
            {
                ctx.Database.EnsureDeleted();
                ctx.Database.EnsureCreated();

                var f1 = new Faction { Name = "Skeliege" };
                var f2 = new Faction { Name = "Monsters" };
                var f3 = new Faction { Name = "Nilfgaard" };
                var f4 = new Faction { Name = "Northern Realms" };
                var f5 = new Faction { Name = "Scioia'tael" };

                var l11 = new Leader { Faction = f1, Name = "Bran Tuirseach" };
                var l12 = new Leader { Faction = f1, Name = "Crach an Craite" };
                var l13 = new Leader { Faction = f1, Name = "Eist Tuirseach" };
                var l14 = new Leader { Faction = f1, Name = "Harald the Cripple" };

                ctx.Factions.AddRange(f1, f2, f3, f4, f5);
                ctx.Leaders.AddRange(l11, l12, l13, l14);
                ctx.SaveChanges();
            }

            using (var ctx = new MyContext())
            {
                var q02 = ctx.LeadersQuery.ToList();
            }
        }
    }

    public class MyContext : DbContext
    {
        public DbSet<Faction> Factions { get; set; }
        public DbSet<Leader> Leaders { get; set; }

        public DbQuery<LeaderQuery> LeadersQuery { get; set; }
        public DbQuery<FactionQuery> FactionsQuery { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            optionsBuilder.UseSqlServer(@"Server=.;Database=QueryTypesRepro;Trusted_Connection=True;MultipleActiveResultSets=True");
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Query<FactionQuery>().ToQuery(() => Set<Leader>().Where(lq => lq.Name != "Foo").Select(lq => new FactionQuery { Name = "Not Foo" }));
            modelBuilder.Query<LeaderQuery>().ToQuery(() => Query<FactionQuery>().Where(fq => fq.Name != "Bar").Select(fq => new LeaderQuery { Name = "Not Bar" }));
        }
    }

    public class Faction
    {
        public int Id { get; set; }
        public string Name { get; set; }

        public List<Leader> Leaders { get; set; }
    }

    public class FactionQuery
    {
        public string Name { get; set; }
    }

    public class Leader
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public Faction Faction { get; set; }
    }

    public class LeaderQuery
    {
        public string Name { get; set; }
    }

we produce the following SQL:

SELECT 1
            FROM [FactionsQuery] AS [fq]
            WHERE ([fq].[Name] <> N'Bar') OR [fq].[Name] IS NULL

which is incorrect because there is no FactionsQuery table

[maumar]

if we enable this, we need to watch out for cycles