On 31-May-2005, Daniel Fischer <[EMAIL PROTECTED]> wrote: > Am Freitag, 27. Mai 2005 02:06 schrieb Shiqi Cao: > > I tried to port some code from ghc 6.2 to ghc 6.4, but I got the > > following error > > > > PrelExts.lhs:41:25: > > Ambiguous occurrence `map' > > It could refer to either `GHC.Base.map', imported from Data.List at > > PrelExts.lhs:11:0-15 > > or `Data.Set.map', imported from Data.Set at > > PrelExts.lhs:10:0-14 > > > > The following is the first part of the code > > > > module PrelExts where > > > > import Data.FiniteMap > > import Data.Set > > import Data.List > > import IO > > > > There is no problem under ghc 6.2. What should I do? ... > To solve your problem, use import controls, for example > > import Data.Set hiding (map) > import qualified Data.Set as Set > > will do fine.
That code only compiles with ghc 6.4, and won't compile with ghc 6.2: you'll get an error for the "hiding (map)" part, because in 6.2 Data.Set does not contain a "map" function. If you want code that compiles with both 6.2 and 6.4 and does not give any warnings with "ghc -Wall", then I think you'll need to use qualified imports, i.e. just the second line above. -- Fergus J. Henderson | "I have always known that the pursuit Galois Connections, Inc. | of excellence is a lethal habit" Phone: +1 503 626 6616 | -- the last words of T. S. Garp. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe