Resolving dependencies...
Configuring json2-types-0.1...
Configuring mtl-2.2.1...
Building json2-types-0.1...
Building mtl-2.2.1...
Installed json2-types-0.1
Configuring old-locale-1.0.0.7...
Building old-locale-1.0.0.7...
Configuring utf8-string-1.0.1.1...
Installed old-locale-1.0.0.7
Building utf8-string-1.0.1.1...
Configuring text-1.2.2.1...
Installed mtl-2.2.1
Building text-1.2.2.1...
Installed utf8-string-1.0.1.1
Installed text-1.2.2.1
Configuring blaze-builder-0.4.0.2...
Configuring parsec-3.1.11...
Building parsec-3.1.11...
Building blaze-builder-0.4.0.2...
Installed blaze-builder-0.4.0.2
Installed parsec-3.1.11
Downloading json2-0.8...
Configuring json2-0.8...
Building json2-0.8...
Failed to install json2-0.8
Build log ( /home/builder/.cabal/logs/json2-0.8.log ):
cabal: Entering directory '/tmp/cabal-tmp-18153/json2-0.8'
Configuring json2-0.8...
Building json2-0.8...
Preprocessing library json2-0.8...
[1 of 7] Compiling Data.JSON2.Query ( src/Data/JSON2/Query.hs, dist/build/Data/JSON2/Query.o )

src/Data/JSON2/Query.hs:171:7: warning: [-Wtabs]
    Tab character found here, and in two further locations.
    Please use spaces instead.
[2 of 7] Compiling Data.JSON2.Pretty ( src/Data/JSON2/Pretty.hs, dist/build/Data/JSON2/Pretty.o )

src/Data/JSON2/Pretty.hs:33:10: error:
    • Illegal instance declaration for ‘Pretty Rational’
        (All instance types must be of the form (T a1 ... an)
         where a1 ... an are *distinct type variables*,
         and each type variable appears at most once in the instance head.
         Use FlexibleInstances if you want to disable this.)
    • In the instance declaration for ‘Pretty Rational’

src/Data/JSON2/Pretty.hs:35:10: error:
    • Illegal instance declaration for ‘Pretty String’
        (All instance types must be of the form (T a1 ... an)
         where a1 ... an are *distinct type variables*,
         and each type variable appears at most once in the instance head.
         Use FlexibleInstances if you want to disable this.)
    • In the instance declaration for ‘Pretty String’
cabal: Leaving directory '/tmp/cabal-tmp-18153/json2-0.8'
cabal: Error: some packages failed to install:
json2-0.8 failed during the building phase. The exception was:
ExitFailure 1