[Haskell-cafe] GHC -WAll, -fwarn-unused-do-bind and Cabal

I'm confused: I'm using GHC 7.0.2 and Cabal 1.10.1.0 with cabal-install 0.10.2. I use -Wall in my Cabal file. If I build a Haskell file with unused do binds, via the GHC API I get no warning, which is normal, since the doc states: The warnings that are not enabled by -Wall are ..., -fwarn-unused-do-bind .... But if I build my project through cabal it gives me the warning! Why is compiling with Cabal giving that extra warning that GHC on its own with the same flags doesn't give? Using --verbose on cabal build does not give any clue, no suspicious extra flag is passed on. Any pointer appreciated! -- JP Moresmau http://jpmoresmau.blogspot.com/