Resolving dependencies... Configuring atomic-primops-0.8.2... Configuring base-orphans-0.7... Building atomic-primops-0.8.2... Building base-orphans-0.7... Installed atomic-primops-0.8.2 Configuring base-prelude-1.2.0.1... Installed base-orphans-0.7 Configuring cabal-doctest-1.0.6... Building base-prelude-1.2.0.1... Building cabal-doctest-1.0.6... Installed base-prelude-1.2.0.1 Configuring semigroups-0.18.4... Building semigroups-0.18.4... Installed cabal-doctest-1.0.6 Configuring th-abstraction-0.2.6.0... Installed semigroups-0.18.4 Configuring transformers-compat-0.6.0.5... Building th-abstraction-0.2.6.0... Building transformers-compat-0.6.0.5... Installed th-abstraction-0.2.6.0 Configuring vector-th-unbox-0.2.1.6... Installed transformers-compat-0.6.0.5 Configuring unagi-chan-0.4.1.0... Building vector-th-unbox-0.2.1.6... Building unagi-chan-0.4.1.0... Installed vector-th-unbox-0.2.1.6 Configuring vector-builder-0.3.4.1... Building vector-builder-0.3.4.1... Installed vector-builder-0.3.4.1 Configuring tagged-0.8.5... Building tagged-0.8.5... Installed unagi-chan-0.4.1.0 Configuring contravariant-1.4.1... Building contravariant-1.4.1... Installed tagged-0.8.5 Configuring math-functions-0.2.1.0... Building math-functions-0.2.1.0... Installed contravariant-1.4.1 Configuring distributive-0.5.3... Building distributive-0.5.3... Installed distributive-0.5.3 Configuring comonad-5.0.3... Building comonad-5.0.3... Installed math-functions-0.2.1.0 Configuring mwc-random-0.13.6.0... Building mwc-random-0.13.6.0... Installed comonad-5.0.3 Configuring bifunctors-5.5.2... Building bifunctors-5.5.2... Installed mwc-random-0.13.6.0 Installed bifunctors-5.5.2 Configuring profunctors-5.2.2... Building profunctors-5.2.2... Installed profunctors-5.2.2 Configuring foldl-1.3.7... Configuring potoki-core-1.5.2... Building potoki-core-1.5.2... Building foldl-1.3.7... Installed potoki-core-1.5.2 Installed foldl-1.3.7 Configuring potoki-0.10.5... Building potoki-0.10.5... Failed to install potoki-0.10.5 Build log ( /home/builder/.cabal/logs/ghc-8.2.2/potoki-0.10.5-LghOKkylrHjFQyl81gV50T.log ): cabal: Entering directory '/tmp/cabal-tmp-4529/potoki-0.10.5' Configuring potoki-0.10.5... Preprocessing library for potoki-0.10.5.. Building library for potoki-0.10.5.. [1 of 7] Compiling Potoki.IO ( library/Potoki/IO.hs, dist/build/Potoki/IO.o ) [2 of 7] Compiling Potoki.Prelude ( library/Potoki/Prelude.hs, dist/build/Potoki/Prelude.o ) [3 of 7] Compiling Potoki.Fetch ( library/Potoki/Fetch.hs, dist/build/Potoki/Fetch.o ) [4 of 7] Compiling Potoki.Produce ( library/Potoki/Produce.hs, dist/build/Potoki/Produce.o ) [5 of 7] Compiling Potoki.Transform.Concurrency ( library/Potoki/Transform/Concurrency.hs, dist/build/Potoki/Transform/Concurrency.o ) [6 of 7] Compiling Potoki.Transform ( library/Potoki/Transform.hs, dist/build/Potoki/Transform.o ) library/Potoki/Transform.hs:11:3: error: Ambiguous occurrence ‘drop’ It could refer to either ‘Potoki.Prelude.drop’, imported from ‘Potoki.Prelude’ at library/Potoki/Transform.hs:39:1-54 (and originally defined in ‘GHC.List’) or ‘Potoki.Transform.drop’, defined at library/Potoki/Transform.hs:82:1 | 11 | drop, | ^^^^ cabal: Leaving directory '/tmp/cabal-tmp-4529/potoki-0.10.5' cabal: Error: some packages failed to install: potoki-0.10.5-LghOKkylrHjFQyl81gV50T failed during the building phase. The exception was: ExitFailure 1