I'm getting errors like this from version 1.1.3 of haskell-regex-tdfa which is now in sid:
Explict error in module Text.Regex.TDFA.NewDFA : compressOrbit,1 reverting to 1.1.2 fixes it. Also, the homepage and the darcs repo given in the cabal file appear to be out of date. Homepage: http://sourceforge.net/projects/lazy-regex Package-URL: http://darcs.haskell.org/packages/regex-unstable/regex-tdfa/
