I've long set my most-recently visited directories to shell variables d1, d2, etc.

On an ancient Fedora machine I could type a command like

$ cp $d1/

and the shell would replace $d1 with text like /home/acctname/projects/blog/ and would then show me the contents of .../blog, like any tab-completion.

Now, both ubuntu wheezy/sid and fedora 16 just -escape the '$', and naturally there are no completions to show.

You can see this behavior in action in an OSX Terminal window. On 10.8, do something like

ls $HOME/ to see what I mean.

Is there a bash shell variable or option that can restore the old behavior?

man bash suggests this is a bug:

   complete (TAB)
          Attempt  to  perform  completion  on  the  text  before  point.  Bash
          attempts completion treating the text as  a  variable  (if  the  text
          begins  with  $),  username (if the text begins with ~), hostname (if
          the text begins with @), or command (including aliases and functions)
          in  turn.   If none of these produces a match, filename completion is
          attempted.

I get the above described completion when a token starts with '~' or a letter. It's just '$'-completion that's broken.