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 StateVar-1.1.1.1 Starting cabal-doctest-1.0.6 Starting call-stack-0.1.0 Starting base-orphans-0.8 Building StateVar-1.1.1.1 Building call-stack-0.1.0 Building cabal-doctest-1.0.6 Building base-orphans-0.8 Completed call-stack-0.1.0 Starting hashable-1.2.7.0 Completed base-orphans-0.8 Starting parallel-3.2.2.0 Completed StateVar-1.1.1.1 Starting primitive-0.6.4.0 Building hashable-1.2.7.0 Building parallel-3.2.2.0 Building primitive-0.6.4.0 Completed cabal-doctest-1.0.6 Starting reflection-2.1.4 Building reflection-2.1.4 Completed parallel-3.2.2.0 Starting semigroups-0.18.5 Building semigroups-0.18.5 Completed hashable-1.2.7.0 Starting tagged-0.8.6 Building tagged-0.8.6 Completed semigroups-0.18.5 Starting th-abstraction-0.2.10.0 Building th-abstraction-0.2.10.0 Completed reflection-2.1.4 Starting transformers-compat-0.6.2 Completed tagged-0.8.6 Starting void-0.7.2 Building transformers-compat-0.6.2 Building void-0.7.2 Completed void-0.7.2 Starting contravariant-1.5 Building contravariant-1.5 Completed th-abstraction-0.2.10.0 Starting unordered-containers-0.2.9.0 Building unordered-containers-0.2.9.0 Completed transformers-compat-0.6.2 Starting distributive-0.6 Completed contravariant-1.5 Starting transformers-base-0.4.5.2 Building transformers-base-0.4.5.2 Building distributive-0.6 Completed primitive-0.6.4.0 Starting exceptions-0.10.0 Building exceptions-0.10.0 Completed transformers-base-0.4.5.2 Starting vector-0.12.0.2 Building vector-0.12.0.2 Completed distributive-0.6 Starting comonad-5.0.4 Completed exceptions-0.10.0 Building comonad-5.0.4 Completed unordered-containers-0.2.9.0 Completed comonad-5.0.4 Starting bifunctors-5.5.3 Building bifunctors-5.5.3 Completed bifunctors-5.5.3 Starting profunctors-5.3 Starting semigroupoids-5.3.2 Building profunctors-5.3 Building semigroupoids-5.3.2 Completed profunctors-5.3 Starting invariant-0.5.1 Building invariant-0.5.1 Completed vector-0.12.0.2 Completed semigroupoids-5.3.2 Starting free-5.1 Building free-5.1 Completed invariant-0.5.1 Completed free-5.1 Starting adjunctions-4.4 Building adjunctions-4.4 Completed adjunctions-4.4 Starting kan-extensions-5.2 Building kan-extensions-5.2 Completed kan-extensions-5.2 Starting lens-4.17 Building lens-4.17 Completed lens-4.17 Starting dualizer-0.1.0.0 Building dualizer-0.1.0.0 Failed to install dualizer-0.1.0.0 Build log ( /home/builder/.cabal/logs/ghc-8.6.3/dualizer-0.1.0.0-8PLaFcNPykdXVhD2zQC1o.log ): cabal: Entering directory '/tmp/cabal-tmp-18212/dualizer-0.1.0.0' Configuring dualizer-0.1.0.0... Preprocessing library for dualizer-0.1.0.0.. Building library for dualizer-0.1.0.0.. [1 of 5] Compiling Categorical.Dual ( src/Categorical/Dual.hs, dist/build/Categorical/Dual.o ) src/Categorical/Dual.hs:51:10: error: • No instance for (Semigroup DualMappings) arising from the superclasses of an instance declaration • In the instance declaration for ‘Monoid DualMappings’ | 51 | instance Monoid DualMappings where | ^^^^^^^^^^^^^^^^^^^ src/Categorical/Dual.hs:363:26: error: • No instance for (Semigroup DualMappings) arising from a use of ‘<>’ • In the second argument of ‘maybe’, namely ‘(newDuals <>)’ In the second argument of ‘($)’, namely ‘maybe newDuals (newDuals <>) oldDuals’ In a stmt of a 'do' block: putQ $ maybe newDuals (newDuals <>) oldDuals | 363 | putQ $ maybe newDuals (newDuals <>) oldDuals | ^^^^^^^^^^^ cabal: Leaving directory '/tmp/cabal-tmp-18212/dualizer-0.1.0.0' cabal: Error: some packages failed to install: dualizer-0.1.0.0-8PLaFcNPykdXVhD2zQC1o failed during the building phase. The exception was: ExitFailure 1