Unable to create a constant value of type .... Only primitive types or enumeration types are supported in this context

The following database query is returning the following error.

I have a feeling it is to do with the contains function within the where clause but im not too sure?

Any ideas??

     var roomToMatch = db.rooms.Where(r=>r.roomNumber==number && r.buildingCode==code).First();
        var yearID = Convert.ToInt32(year);
        var semesterID = Convert.ToInt32(semester);
        var rounds = db.rounds.Where(r => r.semester == semesterID && r.year == yearID);

        int[] days = new int[5] { 1, 2, 3, 4, 5 };
        int[] times = new int[9] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
        List<request> bookings = new List<request>();
        var requests = db.requests.Include(r => r.module.staffs).Where(r => r.deptCode == user).Where(r => r.booked == 1).Where(r => rounds.Contains(r.round)).Where(r => r.rooms.Contains(roomToMatch));
        bookings = requests.ToList();

the full error

    Unable to create a constant value of type 'Timetabling06.Models.room'. Only primitive types or enumeration types are supported in this context.