I'm sure there must be some way to do this...

I can search for priority:none which gives me tasks for which I have not (yet) assigned a priority.

How can I search for those tasks which I have not assigned a location for?

What I'm trying to do is setup a smart list for myself of incomplete tasks due before tomorrow which are either at a specific location or without a location altogether. Logically I think it should look like this:

status:incomplete AND dueBefore:tomorrow AND (location:home OR location:none)

The problem is that last bit doesn't work. Even if I try location:none on its own it doesn't work.

So how do I search for tasks that have no assigned location?

I apologise if this is yet another case of RTFM but I'd appreciate it if you could point me in the right direction.

Thanks.