Resolving dependencies...
Configuring open-union-0.1.0.0...
Building open-union-0.1.0.0...
Preprocessing library open-union-0.1.0.0...

Data/OpenUnion.hs:5:1: parse error on input ‘<<<<<<<’
Failed to install open-union-0.1.0.0
cabal: Error: some packages failed to install:
open-union-0.1.0.0 failed during the building phase. The exception was:
ExitFailure 1