Resolving dependencies...
Configuring mtl-2.2.1...
Configuring random-1.1...
Building mtl-2.2.1...
Building random-1.1...
Installed random-1.1
Installed mtl-2.2.1
Configuring operational-0.2.3.5...
Building operational-0.2.3.5...
Installed operational-0.2.3.5
Configuring Etage-0.1.4...
Building Etage-0.1.4...
Failed to install Etage-0.1.4
Build log ( /home/builder/.cabal/logs/Etage-0.1.4.log ):
cabal: Entering directory '/tmp/cabal-tmp-14062/Etage-0.1.4'
Configuring Etage-0.1.4...
Building Etage-0.1.4...
Preprocessing library Etage-0.1.4...
[ 1 of 12] Compiling Control.Etage.Chan ( lib/Control/Etage/Chan.hs, dist/build/Control/Etage/Chan.o )

lib/Control/Etage/Chan.hs:131:13: error:
    Ambiguous occurrence ‘tryReadMVar’
    It could refer to either ‘Control.Concurrent.MVar.tryReadMVar’,
                             imported from ‘Control.Concurrent.MVar’ at lib/Control/Etage/Chan.hs:41:1-30
                             (and originally defined in ‘GHC.MVar’)
                          or ‘Control.Etage.Chan.tryReadMVar’,
                             defined at lib/Control/Etage/Chan.hs:101:1
cabal: Leaving directory '/tmp/cabal-tmp-14062/Etage-0.1.4'
cabal: Error: some packages failed to install:
Etage-0.1.4 failed during the building phase. The exception was:
ExitFailure 1