Resolving dependencies...
Configuring bytestring-0.9.2.1...
Building bytestring-0.9.2.1...
Installed bytestring-0.9.2.1
Configuring vowpal-utils-0.1.1...
Building vowpal-utils-0.1.1...
Failed to install vowpal-utils-0.1.1
Build log ( /home/builder/.cabal/logs/vowpal-utils-0.1.1.log ):
cabal: Entering directory '/tmp/cabal-tmp-16066/vowpal-utils-0.1.1'
Configuring vowpal-utils-0.1.1...
Building vowpal-utils-0.1.1...
Preprocessing library vowpal-utils-0.1.1...
[1 of 1] Compiling Data.Digest.VowpalHash ( Data/Digest/VowpalHash.lhs, dist/build/Data/Digest/VowpalHash.o )

Data/Digest/VowpalHash.lhs:123:33: error:
    Not in scope: ‘U.fromString’
    No module named ‘U’ is imported.
cabal: Leaving directory '/tmp/cabal-tmp-16066/vowpal-utils-0.1.1'
cabal: Error: some packages failed to install:
vowpal-utils-0.1.1 failed during the building phase. The exception was:
ExitFailure 1