Bug: git ls-files and ignored directories

Hi!

I think I've been bitten by a bug in git ls-files - committed directories (and files therein) which are matched by a "dir/" gitignore rule are not shown by "git ls-files --exclude-standard -i", although they should be. Matched files are shown.

I've found a very brief discussion on this mailing list from March 2011 about this, including a repro procedure which still is valid today, at http://marc.info/?l=git&m=129926031808376&w=4

Is that a known/in progress bug? If yes, (when) can a fix be expected? How can I work around this in the meantime? 
If it's not a bug, how do you do this properly? My original problem was that  I want to list files which have been committed to git but match an existing gitignore pattern. Richard Hansen has written a very nice alias for that (http://stackoverflow.com/a/9370094/599884, with some discussion of this bug in the comments), but due to the present bug this does not work totally correctly. 

Having a built-in git feature for this would be great, btw ("git ls-files --committed-but-ignored"? :-)). Do I have to submit a separate feature request?

thanks, 
Christoph

p.s.: The repro procedure from the linked list discussion:

$ mkdir test
$ cd test
$ git init
$ mkdir testdir
$ touch testdir/test
$ git add testdir/test
$ git commit -m "add test"
$ echo "testdir/" > .gitignore
$ git ls-files --exclude-standard -i