efcore: Simple query filter breaks simple projection

As reported by @klaussj here: https://github.com/aspnet/EntityFrameworkCore/issues/12951#issuecomment-427380358

Removing the query filter fixes the issue.

namespace DemoIssue
{
    public class Entity
    {
        public int Id { get; set; }
        public int? RefEntityId { get; set; }
        public RefEntity RefEntity { get; set; }
    }

    public class RefEntity
    {
        public int Id { get; set; }
        public bool Public { get; set; }
    }

    public class EntityDto
    {
        public int Id { get; set; }
        public int? RefEntityId { get; set; }
        public RefEntityDto RefEntity { get; set; }
    }

    public class RefEntityDto
    {
        public int Id { get; set; }
        public bool Public { get; set; }
    }

    public class DbTestContext : DbContext
    {
        public DbSet<Entity> Entities { get; set; }
        public DbSet<RefEntity> RefEntities { get; set; }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<RefEntity>().HasQueryFilter(f => f.Public == true);
        }

        public DbTestContext(DbContextOptions<DbTestContext> options) : base(options)
        {

        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            using (var connection = new SqliteConnection("DataSource=:memory:"))
            {
                connection.Open();

                var options = new DbContextOptionsBuilder<DbTestContext>()
                    .UseSqlite(connection)
                    .Options;

                using (var db = new DbTestContext(options))
                {
                    db.Database.EnsureCreated();

                    db.RefEntities.Add(new RefEntity()
                    {
                        Id = 1,
                        Public = false
                    });

                    db.Entities.Add(new Entity()
                    {
                        Id = 1,
                        RefEntityId = 1
                    });

                    db.SaveChanges();

                    var notWorking = db.Entities.Select<Entity, EntityDto>(s =>
                        new EntityDto
                        {
                            Id = s.Id,
                            RefEntity = s.RefEntity == null ?
                                null :
                                new RefEntityDto()
                                {
                                    Id = s.RefEntity.Id,
                                    Public = s.RefEntity.Public
                                },
                            RefEntityId = s.RefEntityId
                        }).Single(p => p.Id == 1);
                }
            }
        }
    }
}

Exception:

Unhandled Exception: System.InvalidOperationException: Nullable object must have a value.
   at lambda_method(Closure , QueryContext , TransparentIdentifier`2 )
   at Microsoft.EntityFrameworkCore.Query.ExpressionVisitors.Internal.ProjectionShaper.TypedProjectionShaper`3.Shape(QueryContext queryContext, ValueBuffer& valueBuffer)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.BufferlessMoveNext(DbContext _, Boolean buffer)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.MoveNext()
   at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqOperatorProvider.ResultEnumerable`1.GetEnumerator()
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqOperatorProvider.ExceptionInterceptor`1.EnumeratorExceptionInterceptor.MoveNext()
   at System.Linq.Enumerable.TryGetFirst[TSource](IEnumerable`1 source, Boolean& found)
   at System.Linq.Enumerable.First[TSource](IEnumerable`1 source)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.<>c__DisplayClass15_1`1.<CompileQueryCore>b__0(QueryContext qc)
   at System.Linq.Queryable.Single[TSource](IQueryable`1 source, Expression`1 predicate)
   at DemoIssue.Program.Main(String[] args) in C:\Stuff\TwoOneCore\TwoOneCore\Program.cs:line 79