Resolving dependencies... Configuring colour-2.3.4... Configuring data-ordlist-0.4.7.0... Building data-ordlist-0.4.7.0... Building colour-2.3.4... Installed data-ordlist-0.4.7.0 Configuring transformers-compat-0.5.1.4... Building transformers-compat-0.5.1.4... Installed transformers-compat-0.5.1.4 Installed colour-2.3.4 Configuring ansi-terminal-0.8.0.1... Building ansi-terminal-0.8.0.1... Installed ansi-terminal-0.8.0.1 Configuring ansi-wl-pprint-0.6.8.2... Building ansi-wl-pprint-0.6.8.2... Installed ansi-wl-pprint-0.6.8.2 Configuring optparse-applicative-0.14.0.0... Building optparse-applicative-0.14.0.0... Installed optparse-applicative-0.14.0.0 Configuring perfect-hash-generator-0.2.0.3... Building perfect-hash-generator-0.2.0.3... Failed to install perfect-hash-generator-0.2.0.3 Build log ( /home/builder/.cabal/logs/ghc-8.2.2/perfect-hash-generator-0.2.0.3-GDiY8mSDlRiD3mQxZmD3Xo.log ): cabal: Entering directory '/tmp/cabal-tmp-13588/perfect-hash-generator-0.2.0.3' Configuring perfect-hash-generator-0.2.0.3... Preprocessing library for perfect-hash-generator-0.2.0.3.. Building library for perfect-hash-generator-0.2.0.3.. [1 of 4] Compiling Data.PerfectHash.Hashing ( src/Data/PerfectHash/Hashing.hs, dist/build/Data/PerfectHash/Hashing.o ) [2 of 4] Compiling Data.PerfectHash.Lookup ( src/Data/PerfectHash/Lookup.hs, dist/build/Data/PerfectHash/Lookup.o ) [3 of 4] Compiling Data.PerfectHash.Construction ( src/Data/PerfectHash/Construction.hs, dist/build/Data/PerfectHash/Construction.o ) [4 of 4] Compiling Paths_perfect_hash_generator ( dist/build/autogen/Paths_perfect_hash_generator.hs, dist/build/Paths_perfect_hash_generator.o ) Preprocessing executable 'hash-perfectly-ints-demo' for perfect-hash-generator-0.2.0.3.. Building executable 'hash-perfectly-ints-demo' for perfect-hash-generator-0.2.0.3.. Warning: Enabling workaround for Main module 'Main' listed in 'other-modules' illegaly! [1 of 4] Compiling Exercise ( test/Exercise.hs, dist/build/hash-perfectly-ints-demo/hash-perfectly-ints-demo-tmp/Exercise.o ) [2 of 4] Compiling Ints.Main ( demo/Ints/Main.hs, dist/build/hash-perfectly-ints-demo/hash-perfectly-ints-demo-tmp/Ints/Main.o ) [3 of 4] Compiling Paths_perfect_hash_generator ( dist/build/hash-perfectly-ints-demo/autogen/Paths_perfect_hash_generator.hs, dist/build/hash-perfectly-ints-demo/hash-perfectly-ints-demo-tmp/Paths_perfect_hash_generator.o ) [4 of 4] Compiling Strings.Main ( demo/Strings/Main.hs, dist/build/hash-perfectly-ints-demo/hash-perfectly-ints-demo-tmp/Strings/Main.o ) : error: output was redirected with -o, but no output will be generated because there is no Main module. cabal: Leaving directory '/tmp/cabal-tmp-13588/perfect-hash-generator-0.2.0.3' cabal: Error: some packages failed to install: perfect-hash-generator-0.2.0.3-GDiY8mSDlRiD3mQxZmD3Xo failed during the building phase. The exception was: ExitFailure 1