Query: client method around qsre followed by projecting collection navigation throws during compilation

[maumar]

Found when working on workaround for #12678

repro:

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

                var check = new Check { CheckTemplateId = 1 };

                var examiner1 = new Examiner();
                var examiner2 = new Examiner();

                var user1 = new User();
                var implementer1 = new Implementer { User = user1 };

                var user2 = new User();
                var implementer2 = new Implementer { User = user2 };

                var template = new CheckTemplate { Description = "1", Examiners = new List<Examiner> { examiner1, examiner2 }, Implementers = new List<Implementer> { implementer1, implementer2 } };

                ctx.Checks.Add(check);
                ctx.Examiners.AddRange(examiner1, examiner2);
                ctx.Users.AddRange(user1, user2);
                ctx.Implementers.AddRange(implementer1, implementer2);
                ctx.CheckTemplates.Add(template);
                ctx.SaveChanges();
            }

            using (var db = new MyContext())
            {
                var checkId = 1;

                var data = (from c in db.Checks
                                 join ct in db.CheckTemplates
                                      .Include(a => a.Implementers).ThenInclude(u => u.User)
                                 on c.CheckTemplateId equals ct.CheckTemplateId
                                 where c.CheckId == checkId
                                 select new
                                 {
                                     CheckId = c.CheckId,
                                     Description = ct.Description,
                                     Implementers = Client(ct).Implementers,
                                     NumExaminers = ct.Examiners.Count
                                 }).FirstOrDefault();
            }
        }

        public static T Client<T>(T s) => s;

        public static List<Implementer> ProjectImplementers(CheckTemplate checkTemplate) => checkTemplate.Implementers;

        public static TResult ClientProject<TSource, TResult>(TSource source, Func<TSource, TResult> selector) => selector(source);
    }

    public class Check
    {
        public int CheckId { get; set; }

        public int CheckTemplateId { get; set; }
    }

    public class CheckTemplate
    {
        public int CheckTemplateId { get; set; }
        public string Description { get; set; }

        public List<Implementer> Implementers { get; set; }

        public List<Examiner> Examiners { get; set; }
    }

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

    public class Implementer
    {
        public int Id { get; set; }
        public User User { get; set; }
    }

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

    public class MyContext : DbContext
    {
        public DbSet<Check> Checks { get; set; }

        public DbSet<CheckTemplate> CheckTemplates { get; set; }

        public DbSet<Examiner> Examiners { get; set; }

        public DbSet<User> Users { get; set; }

        public DbSet<Implementer> Implementers { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            optionsBuilder.UseSqlServer(@"Server=.;Database=Repro12678;Trusted_Connection=True;MultipleActiveResultSets=True");
        }
    }

exception:

System.ArgumentNullException: 'Value cannot be null.'

   at Microsoft.EntityFrameworkCore.Utilities.Check.NotNull[T](T value, String parameterName) in D:\git\EntityFrameworkCore\src\Shared\Check.cs:line 28
   at Microsoft.EntityFrameworkCore.Query.QueryCompilationContext.RegisterCorrelatedSubqueryMetadata(MainFromClause mainFromClause, Boolean trackingQuery, INavigation firstNavigation, INavigation collectionNavigation, IQuerySource parentQuerySource) in D:\git\EntityFrameworkCore\src\EFCore\Query\QueryCompilationContext.cs:line 96
   at Microsoft.EntityFrameworkCore.Query.ExpressionVisitors.Internal.CorrelatedCollectionFindingExpressionVisitor.<>c__DisplayClass7_0.<TryMarkSubQuery>b__0(IReadOnlyList`1 properties, IQuerySource querySource) in D:\git\EntityFrameworkCore\src\EFCore\Query\ExpressionVisitors\Internal\CorrelatedCollectionFindingExpressionVisitor.cs:line 111
   at Microsoft.EntityFrameworkCore.Query.EntityQueryModelVisitor.BindPropertyExpressionCore[TResult](Expression propertyExpression, IQuerySource querySource, Func`3 propertyBinder) in D:\git\EntityFrameworkCore\src\EFCore\Query\EntityQueryModelVisitor.cs:line 1825
   at Microsoft.EntityFrameworkCore.Query.EntityQueryModelVisitor.BindNavigationPathPropertyExpression[TResult](Expression propertyExpression, Func`3 propertyBinder) in D:\git\EntityFrameworkCore\src\EFCore\Query\EntityQueryModelVisitor.cs:line 1723
   at Microsoft.EntityFrameworkCore.Query.ExpressionVisitors.Internal.CorrelatedCollectionFindingExpressionVisitor.TryMarkSubQuery(SubQueryExpression expression) in D:\git\EntityFrameworkCore\src\EFCore\Query\ExpressionVisitors\Internal\CorrelatedCollectionFindingExpressionVisitor.cs:line 103
   at Microsoft.EntityFrameworkCore.Query.ExpressionVisitors.Internal.CorrelatedCollectionFindingExpressionVisitor.VisitMethodCall(MethodCallExpression node) in D:\git\EntityFrameworkCore\src\EFCore\Query\ExpressionVisitors\Internal\CorrelatedCollectionFindingExpressionVisitor.cs:line 75
   at System.Linq.Expressions.MethodCallExpression.Accept(ExpressionVisitor visitor)
   at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
   at System.Linq.Expressions.ExpressionVisitor.VisitUnary(UnaryExpression node)
   at System.Linq.Expressions.UnaryExpression.Accept(ExpressionVisitor visitor)
   at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
   at System.Linq.Expressions.ExpressionVisitor.VisitAndConvert[T](ReadOnlyCollection`1 nodes, String callerName)
   at Remotion.Linq.Parsing.RelinqExpressionVisitor.VisitNew(NewExpression expression)
   at System.Linq.Expressions.NewExpression.Accept(ExpressionVisitor visitor)
   at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
   at Remotion.Linq.Clauses.SelectClause.TransformExpressions(Func`2 transformation)
   at Microsoft.EntityFrameworkCore.Query.EntityQueryModelVisitor.OptimizeQueryModel(QueryModel queryModel, Boolean asyncQuery) in D:\git\EntityFrameworkCore\src\EFCore\Query\EntityQueryModelVisitor.cs:line 338
   at Microsoft.EntityFrameworkCore.Query.RelationalQueryModelVisitor.OptimizeQueryModel(QueryModel queryModel, Boolean asyncQuery) in D:\git\EntityFrameworkCore\src\EFCore.Relational\Query\RelationalQueryModelVisitor.cs:line 1345
   at Microsoft.EntityFrameworkCore.Query.EntityQueryModelVisitor.CreateQueryExecutor[TResult](QueryModel queryModel) in D:\git\EntityFrameworkCore\src\EFCore\Query\EntityQueryModelVisitor.cs:line 170
   at Microsoft.EntityFrameworkCore.Storage.Database.CompileQuery[TResult](QueryModel queryModel) in D:\git\EntityFrameworkCore\src\EFCore\Storage\Database.cs:line 70
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.CompileQueryCore[TResult](Expression query, IQueryModelGenerator queryModelGenerator, IDatabase database, IDiagnosticsLogger`1 logger, Type contextType) in D:\git\EntityFrameworkCore\src\EFCore\Query\Internal\QueryCompiler.cs:line 126
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.<>c__DisplayClass13_0`1.<Execute>b__0() in D:\git\EntityFrameworkCore\src\EFCore\Query\Internal\QueryCompiler.cs:line 91
   at Microsoft.EntityFrameworkCore.Query.Internal.CompiledQueryCache.GetOrAddQueryCore[TFunc](Object cacheKey, Func`1 compiler) in D:\git\EntityFrameworkCore\src\EFCore\Query\Internal\CompiledQueryCache.cs:line 67
   at Microsoft.EntityFrameworkCore.Query.Internal.CompiledQueryCache.GetOrAddQuery[TResult](Object cacheKey, Func`1 compiler) in D:\git\EntityFrameworkCore\src\EFCore\Query\Internal\CompiledQueryCache.cs:line 44
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.Execute[TResult](Expression query) in D:\git\EntityFrameworkCore\src\EFCore\Query\Internal\QueryCompiler.cs:line 87
   at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.Execute[TResult](Expression expression) in D:\git\EntityFrameworkCore\src\EFCore\Query\Internal\EntityQueryProvider.cs:line 62
   at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source)
   at Repro12678.Program.Main(String[] args) in D:\Projects\Repro12678\Repro12678\Program.cs:line 42

[maumar]

fixed in c9605ea