LINQ return type for nested group query

You can find what the type of vehicleGroupedByDate is by hovering the mouse over the 'var' keyword.
Assuming that Date's type is DateTime and Vehicle's type is String, it should be:
 IGrouping<DateTime, IGrouping<string, LogRecord>>

I tried using the suggested return type and get error

Error      CS0266      Cannot implicitly convert type 'System.Collections.Generic.IEnumerable<System.Linq.IGrouping<System.DateTime, System.Linq.IGrouping<string, BodyGuardDesktop.BodyGuardUserFriendlyLogRecord>>>' to 'System.Linq.IGrouping<System.DateTime, System.Linq.IGrouping<string, System.Collections.Generic.List<BodyGuardDesktop.BodyGuardUserFriendlyLogRecord>>>'. An explicit conversion exists (are you missing a cast?)


public IGrouping<DateTime, IGrouping<string, List<BodyGuardUserFriendlyLogRecord>>> GetVehicleDetections(List<BodyGuardUserFriendlyLogRecord> recsByDate)
        {
            var vehicleQuery = from daterecs in recsByDate
                                       where daterecs.Event == "Detection"
                                       orderby daterecs.Date
                                       group daterecs by daterecs.Date into vrecs
                                       from vrecs2 in
                                           (
                                              from daterecs in vrecs
                                              orderby daterecs.Time
                                              group daterecs by daterecs.Vehicle
                                           )
                                       group vrecs2 by vrecs.Key;

            return vehicleQuery;
        }

The error message gave you the type you were looking for:
IEnumerable<IGrouping<DateTime, IGrouping<string, List<BodyGuardUserFriendlyLogRecord>>>>

When I tried it, I checked only the items type, so the IEnumerable was missing.

Changed to type as you suggest and get error

Severity      Code      Description      Project      File      Line      Suppression State
Error      CS0266      Cannot implicitly convert type 'System.Collections.Generic.IEnumerable<System.Linq.IGrouping<System.DateTime, System.Linq.IGrouping<string, BodyGuardDesktop.BodyGuardUserFriendlyLogRecord>>>' to 'System.Collections.Generic.IEnumerable<System.Linq.IGrouping<System.DateTime, System.Linq.IGrouping<string, System.Collections.Generic.List<BodyGuardDesktop.BodyGuardUserFriendlyLogRecord>>>>'. An explicit conversion exists (are you missing a cast?)      


public IEnumerable<IGrouping<DateTime, IGrouping<string, List<BodyGuardUserFriendlyLogRecord>>>>
        GetVehicleDetections(List<BodyGuardUserFriendlyLogRecord> recsByDate)
        {
            var vehicleQuery = from daterecs in recsByDate
                               where daterecs.Event == "Detection"
                               orderby daterecs.Date
                               group daterecs by daterecs.Date into vrecs
                               from vrecs2 in
                                   (
                                      from daterecs in vrecs
                                      orderby daterecs.Time
                                      group daterecs by daterecs.Vehicle
                                   )
                               group vrecs2 by vrecs.Key;
            return vehicleQuery;
        }

Thanks for your help