Warning: The install command is a part of the legacy v1 style of cabal usage. Please switch to using either the new project style and the new-install command or the legacy v1-install alias as new-style projects will become the default in the next version of cabal-install. Please file a bug if you cannot replicate a working v1- use case with the new-style commands. For more information, see: https://wiki.haskell.org/Cabal/NewBuild Resolving dependencies... Starting validity-0.9.0.2 Starting random-1.1 Building validity-0.9.0.2 Building random-1.1 Completed validity-0.9.0.2 Starting validity-text-0.3.1.0 Building validity-text-0.3.1.0 Completed random-1.1 Starting splitmix-0.0.3 Building splitmix-0.0.3 Completed validity-text-0.3.1.0 Completed splitmix-0.0.3 Starting QuickCheck-2.13.2 Building QuickCheck-2.13.2 Completed QuickCheck-2.13.2 Starting genvalidity-0.9.1.0 Building genvalidity-0.9.1.0 Completed genvalidity-0.9.1.0 Starting genvalidity-text-0.7.0.1 Building genvalidity-text-0.7.0.1 Failed to install genvalidity-text-0.7.0.1 Build log ( /home/builder/.cabal/logs/ghc-8.6.3/genvalidity-text-0.7.0.1-BSqFUfXai592btPlec2aWp.log ): cabal: Entering directory '/tmp/cabal-tmp-27892/genvalidity-text-0.7.0.1' Configuring genvalidity-text-0.7.0.1... Preprocessing library for genvalidity-text-0.7.0.1.. Building library for genvalidity-text-0.7.0.1.. [1 of 2] Compiling Data.GenValidity.Text ( src/Data/GenValidity/Text.hs, dist/build/Data/GenValidity/Text.o ) src/Data/GenValidity/Text.hs:39:10: error: Variable not in scope: genListLength :: Gen Int | 39 | len <- genListLength | ^^^^^^^^^^^^^ src/Data/GenValidity/Text.hs:44:10: error: Variable not in scope: genListLength :: Gen Int | 44 | len <- genListLength | ^^^^^^^^^^^^^ cabal: Leaving directory '/tmp/cabal-tmp-27892/genvalidity-text-0.7.0.1' cabal: Error: some packages failed to install: genvalidity-text-0.7.0.1-BSqFUfXai592btPlec2aWp failed during the building phase. The exception was: ExitFailure 1