I have stumbled across a slight problem in `tramp-handle-insert-directory' in
tramp.el.

When operating against a system where `ls' support "--dired", there is
some code to iterate across the line of data tagged with
//DIRED//. However, after seeing the tag (with `looking-at') it uses
among other things `forward-word' to reposition itself which will fail
if the user has modified the default syntax table in certain ways (which
was what I was doing and then was surprised to see tramp fail).

One could perhaps argue that there are some deeply rooted assumptions
about `/' not being a word constituent character but apart from the fact
that I do not believe I have seen it documented anywhere that one cannot
change the default syntax allocations, it is rather silly to have such a
dependency in tramp when it is so easy to have a more robust solution.

I have attached a diff with a proposal for a fix.