Another expansion (substitution?) question

[Vin Shelton <shelton@icd.teradyne.com>]

Sorry for more questions, but I can't quite figure this one out.

I have a short function that lists all the matching sub-directories
under a list of directories.  This single line is most of the
function:

    print -l ${^$(all_dirs)}/$=~^*(N/:t) | sort -u

I thought I'd like to get rid of the 'sort -u' process, but I can't do
it all in one step.  The following works:

    x=( ${^$(all_dirs)}/$=~^*(N/:t) )
    print -l ${(ou)x}

but when I try to remove the temporary assignment to x, here is what I
get:

    print -l ${(ou)${^$(all_dirs)}/$=~^*(N/:t)}
    zsh: bad pattern: emacs* o*(N

It looks to me that what is happening is that the / is being
interpreted as starting a substitution.  I've tried doubling and
tripling the /, and I've tried quoting the / with a \, but nothing has
produced the desired effect.

I'm running with the latest CVS version, but I see similar problems
with 4.0.7.

Thanks for your time,
  Vin