[Haskell-cafe] Re: Strafunski/overlapping instances in ghc-6.5

Christian Maeder maeder at tzi.de
Mon Apr 3 12:41:40 EDT 2006

Christopher Brown wrote:
> Christian,
>> Did you try the switch -fallow-overlapping-instances when compiling?
> Yes, but it doesn't seem to make much difference.

Maybe a couple of more library files have not been translated with the 
above flag.


In fact I became a problem with a Show instance and ghc-6.5.20060211


     Overlapping instances for Show AllMaps
       arising from use of `GHC.Show.$dmshowList' at OMDoc/HetsDefs.hs:649:0
     Matching instances:
       instance (Show a, Show b, Show c, Show d, Show e, Show f) =>
                Show (a, b, c, d, e, f)
         -- Imported from GHC.Show
       instance [overlap ok] Show AllMaps
         -- Defined at OMDoc/HetsDefs.hs:649:0
     In the expression: GHC.Show.$dmshowList
     In the definition of `showList': showList = GHC.Show.$dmshowList
     In the definition for method `showList'

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