Excerpts from Martijn van Steenbergen's message of Wed Jan 28 17:33:18 +0100 2009: > This is a bug in GHC. See: > > http://hackage.haskell.org/trac/ghc/ticket/2267 > > I have the same problem in several of my source files. :-(
Sometimes swaping the import lists does hide this wrong warning. Including in this example. > Michael Snoyman wrote: > > I was writing code similar to the following and compiling with "-Wall > > -Werror." Clearly I *am* using Data.ByteString for the function signatures. > > > > {-# OPTIONS_GHC -fwarn-unused-imports -Werror #-} > > import qualified Data.ByteString as B > > import qualified Data.ByteString.UTF8 as BU > > > > toString :: B.ByteString -> String > > toString = BU.toString > > > > fromString :: String -> B.ByteString > > fromString = BU.fromString > > > > main :: IO () > > main = putStrLn $ toString $ fromString "Hello World!" > > > > > > The warning I get is: > > > > > > Unused.hs:2:0: > > Warning: Module `Data.ByteString' is imported, but nothing from it > > is used, > > except perhaps instances visible in `Data.ByteString' > > To suppress this warning, use: import Data.ByteString() > > > > > > > > Am I doing something wrong or is this a bug in GHC? > > > > Thanks, > > Michael > > > > > > ------------------------------------------------------------------------ > > > > _______________________________________________ > > Haskell-Cafe mailing list > > Haskell-Cafe@haskell.org > > http://www.haskell.org/mailman/listinfo/haskell-cafe > -- Nicolas Pouillard _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe