Ticket #59 (reopened bug report)
cabal install doesn't get happy
|Reported by:||Neil Mitchell||Owned by:||nibro|
haskell-src-exts has an implicit dependency on happy for the parser. If happy isn't already installed then cabal install haskell-src-exts doesn't work, it would be great if this could be fixed. This problem has shown up for real users trying to install both derive and hlint - failing when installing haskell-src-exts because of the lack of happy.
Not sure how you fix this with Cabal, but someone on the cabal list might know.