Support type cast with a complex property defined on the derived type in groupby

Assemblies affected

• Microsoft.AspNetCore.OData 8.x
• Microsoft.AspNetCore.OData 9.x

Describe the bug
Grouping by a nested property of a derived type does not return the expected results. Scenario uncovered here

Reproduce steps
Use the following code for a simple OData service to repro the issue

// Data models
namespace Microsoft.AspNetCore.OData.E2E.Tests.DollarApply
{   
    public class MyCustomer
    {
        public int Id { get; set; }
        public MyAddress Address { get; set; }
    }

    public class MyAddress
    {
        public string Street { get; set; }
    }

    public class MyHomeAddress : MyAddress
    {
        public MyCity City { get; set; } // Complex property
    }

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


// Edm model
var builder = new ODataConventionModelBuilder();
            
builder.EntitySet<MyCustomer>("MyCustomers");
builder.ComplexType<MyAddress>();
builder.ComplexType<MyHomeAddress>();
builder.ComplexType<MyCity>();

var model = builder.GetEdmModel();


// Controller
public class MyCustomersController : ODataController
{
    private static readonly List<MyCustomer> myCustomers = new List<MyCustomer>
    {
        new MyCustomer
        {
            Id = 1,
            Address = new MyHomeAddress { Street = "High Street", City = new MyCity { Name = "Belfast" } }
        },
        new MyCustomer
        {
            Id = 2,
            Address = new MyHomeAddress { Street = "Moore Street", City = new MyCity { Name = "Dublin" } }
        }
    };

    [EnableQuery]
    public ActionResult<IEnumerable<MyCustomer>> Get()
    {
        return myCustomers;
    }
}

Data Model
Shared in the "Reproduce steps" section

EDM (CSDL) Model
Shared in the "Reproduce steps" section

Request/Response
Request:

GET http://localhost/MyCustomers?$apply=groupby((Address/Microsoft.AspNetCore.OData.E2E.Tests.DollarApply.MyHomeAddress/City/Name))

Response:

{"value":[{"Address":{}},{"Address":{}}]}

Expected behavior
The following response should be returned:

{"value":[{"Address":{"City":{"Name":"Belfast"}}},{"Address":{"City":{"Name":"Dublin"}}}]}

Start by running the supplied OData service and the $apply=groupby request against Microsoft.AspNetCore.OData 8.x or 9.x. Trace the handling of the derived-type cast and nested complex property; done means the response includes City.Name with Belfast and Dublin rather than empty Address objects.