Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> Since my bookmarks are function names, substring completion is what I
>> desire.  (Many functions share the *same* prefix)
>
> I haven't changed the default, but I have added a `category' of
> `bookmark', so you can use substring completion simply by customizing
> completion-category-overrides.

Thanks for this patch.

Good news: 
    I can confirm that `substring' for `bookmark' category works.

        (custom-set-variables
         '(completion-category-overrides
           (quote ((buffer (styles basic substring))
                   (bookmark (styles substring))))))    

Bad news: 
    `icomplete-mode' never kicks in for `C-x r b' (even with default
    setting of `completion-category-overrides').  Once I reverse your
    changes icomplete-mode kicks in.

        $ bzr merge . -r 110680..110679 
  
    Something is surely amiss.

Request:
    Following patch advertizes new category.