Resolving dependencies... Configuring vector-algorithms-0.7.0.1... Building vector-algorithms-0.7.0.1... Installed vector-algorithms-0.7.0.1 Configuring mono-traversable-1.0.8.1... Building mono-traversable-1.0.8.1... Installed mono-traversable-1.0.8.1 Configuring transaction-0.1.1.2... Building transaction-0.1.1.2... Failed to install transaction-0.1.1.2 Build log ( /home/builder/.cabal/logs/ghc-8.2.2/transaction-0.1.1.2-6nA90lvwg5ZGOpRrWcJSWk.log ): cabal: Entering directory '/tmp/cabal-tmp-18999/transaction-0.1.1.2' Configuring transaction-0.1.1.2... Preprocessing library for transaction-0.1.1.2.. Building library for transaction-0.1.1.2.. [1 of 1] Compiling Data.Transaction ( src/Data/Transaction.hs, dist/build/Data/Transaction.o ) src/Data/Transaction.hs:211:17: error: • Variable not in scope: length :: Transaction a -> Int • Perhaps you meant ‘olength’ (imported from Data.MonoTraversable) Perhaps you want to remove ‘length’ from the explicit hiding list in the import of ‘Prelude’ (src/Data/Transaction.hs:(35,1)-(57,3)). | 211 | lengthIndex = length | ^^^^^^ cabal: Leaving directory '/tmp/cabal-tmp-18999/transaction-0.1.1.2' cabal: Error: some packages failed to install: bookkeeping-0.4.0.0-sD0RmmT1MW1rtau5OCgDz depends on bookkeeping-0.4.0.0 which failed to install. transaction-0.1.1.2-6nA90lvwg5ZGOpRrWcJSWk failed during the building phase. The exception was: ExitFailure 1