Mattias Engdegård wrote:

> Is this useful, or a pointless waste of time?

I think it's useful, except that the last entry (in dabbrev.el) seems to be a 
false alarm, as a regexp pattern is initially nil but is assigned something else 
before use, and the trawler assumes it's nil. I installed the attached patch 
into master to fix the other issues as best I could. Thanks.