The AuthMan.hs is using record wildcards, but this doesn't appear to be specified by default in the cabal file.
cabal install snap
Fails with an error helpfully suggesting that I run with -XRecordWildCards
Running the following successfully compiles:
cabal install --ghc-option=-XRecordWildCards snap
cabal install snap -fhint
(i.e. latest Haskell platform)
This is actually already resolved, but I'll leave this issue here until the update is released as long as no one else minds.
This should be fixed now. Please re-open otherwise.