I did the following in my repository:

krc@bongo:~/ghc-hacking$ darcs push --dry-run
kirsten@darcs.haskell.org:/home/darcs/ghc
Would push the following changes:
[changes snipped]
Making no changes:  this is a dry run.

darcs worked correctly in that case. Then I tried doing this:

krc@bongo:~/ghc-hacking$ darcs push --dry-run
kirsten@darcs.haskell.org:/home/darcs/ghc --match 'name Remove'
Pushing to "kirsten@darcs.haskell.org:/home/darcs/ghc"...
Would push the following changes:
[changes snipped]
Making no changes:  this is a dry run.

Notice that the first line it prints out is "Pushing to..." even though it's a
dry run. I checked, and the patches didn't actually get pushed; it was the
message that was wrong. It would seem that this happens when you combine
--dry-run with --match, since it printed out the right messages when I just did
--dry-run.

This seems to be pretty clearly a bug (and probably took several years off my
life before I confirmed that it did not, in fact, push my patches).