CODEWITHSUNDEEP
ghccabal
thor
thor

Reputation: 22470

cabal install djinn-lib with GHC 8.4?

I'm trying to install djinn-lib with GHC 8.4.1 (from Ubuntu 16.04 apt-get). 

$ cabal install djinn-lib

But I get an error about ambiguity in the <> operator as shown at the bottom.

Does anyone know how to go about fixing it?

The cabal version I used was:

$ cabal --version
cabal-install version 2.2.0.0
compiled using version 2.2.0.0 of the Cabal library

The error message is:

$ cabal install djinn-lib
Resolving dependencies...
Configuring djinn-lib-0.0.1.2...
Preprocessing library for djinn-lib-0.0.1.2..
Building library for djinn-lib-0.0.1.2..
[1 of 4] Compiling Djinn.LJTFormula ( src/Djinn/LJTFormula.hs, dist/build/Djinn/LJTFormula.o )
[2 of 4] Compiling Djinn.LJT        ( src/Djinn/LJT.hs, dist/build/Djinn/LJT.o )
[3 of 4] Compiling Djinn.HTypes     ( src/Djinn/HTypes.hs, dist/build/Djinn/HTypes.o )

src/Djinn/HTypes.hs:242:29: error:
    Ambiguous occurrence ‘<>’
    It could refer to either ‘Prelude.<>’,
                             imported from ‘Prelude’ at src/Djinn/HTypes.hs:5:8-19
                             (and originally defined in ‘GHC.Base’)
                          or ‘Text.PrettyPrint.HughesPJ.<>’,
                             imported from ‘Text.PrettyPrint.HughesPJ’ at src/Djinn/HTypes.hs:36:67-70
    |
242 | ppPat _ (HPAt s p) = text s <> text "@" <> ppPat 10 p
    |                             ^^

src/Djinn/HTypes.hs:242:41: error:
    Ambiguous occurrence ‘<>’
    It could refer to either ‘Prelude.<>’,
                             imported from ‘Prelude’ at src/Djinn/HTypes.hs:5:8-19
                             (and originally defined in ‘GHC.Base’)
                          or ‘Text.PrettyPrint.HughesPJ.<>’,
                             imported from ‘Text.PrettyPrint.HughesPJ’ at src/Djinn/HTypes.hs:36:67-70
    |
242 | ppPat _ (HPAt s p) = text s <> text "@" <> ppPat 10 p
    |                                         ^^
Failed to install djinn-lib-0.0.1.2
cabal: Error: some packages failed to install:
djinn-lib-0.0.1.2-72XYG7inpNR6A7gk4acAK4 failed during the building phase. The
exception was:
ExitFailure 1

Upvotes: 0

Views: 90

Answers (1)

sclv
sclv

Reputation: 38893

The identifier <> was added to the prelude and it clashes with the existing one from HughesPJ. You can add the line import Prelude hiding((<>>)) to the imports section of the files in question to fix this...

Upvotes: 0

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