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 type-combinators-0.2.4.3 Building type-combinators-0.2.4.3 Failed to install type-combinators-0.2.4.3 Build log ( /home/builder/.cabal/logs/ghc-8.6.3/type-combinators-0.2.4.3-5vNMFCYBj1Q3v5oDQ6r4Jj.log ): cabal: Entering directory '/tmp/cabal-tmp-11210/type-combinators-0.2.4.3' Configuring type-combinators-0.2.4.3... Preprocessing library for type-combinators-0.2.4.3.. Building library for type-combinators-0.2.4.3.. [ 1 of 32] Compiling Type.Family.Constraint ( src/Type/Family/Constraint.hs, dist/build/Type/Family/Constraint.o ) [ 2 of 32] Compiling Type.Class.Known ( src/Type/Class/Known.hs, dist/build/Type/Class/Known.o ) [ 3 of 32] Compiling Type.Class.Witness ( src/Type/Class/Witness.hs, dist/build/Type/Class/Witness.o ) [ 4 of 32] Compiling Type.Family.Bool ( src/Type/Family/Bool.hs, dist/build/Type/Family/Bool.o ) [ 5 of 32] Compiling Type.Class.Higher ( src/Type/Class/Higher.hs, dist/build/Type/Class/Higher.o ) [ 6 of 32] Compiling Data.Type.Boolean ( src/Data/Type/Boolean.hs, dist/build/Data/Type/Boolean.o ) [ 7 of 32] Compiling Type.Family.Monoid ( src/Type/Family/Monoid.hs, dist/build/Type/Family/Monoid.o ) [ 8 of 32] Compiling Type.Family.Maybe ( src/Type/Family/Maybe.hs, dist/build/Type/Family/Maybe.o ) [ 9 of 32] Compiling Data.Type.Option ( src/Data/Type/Option.hs, dist/build/Data/Type/Option.o ) [10 of 32] Compiling Type.Family.Either ( src/Type/Family/Either.hs, dist/build/Type/Family/Either.o ) [11 of 32] Compiling Data.Type.Disjunction ( src/Data/Type/Disjunction.hs, dist/build/Data/Type/Disjunction.o ) [12 of 32] Compiling Type.Family.Tuple ( src/Type/Family/Tuple.hs, dist/build/Type/Family/Tuple.o ) [13 of 32] Compiling Type.Family.List ( src/Type/Family/List.hs, dist/build/Type/Family/List.o ) [14 of 32] Compiling Type.Family.Nat ( src/Type/Family/Nat.hs, dist/build/Type/Family/Nat.o ) src/Type/Family/Nat.hs:95:13: error: Malformed head of type or class declaration: (x :: N) * (y :: N) | 95 | type family (x :: N) * (y :: N) :: N where | ^^^^^^^^ cabal: Leaving directory '/tmp/cabal-tmp-11210/type-combinators-0.2.4.3' cabal: Error: some packages failed to install: tuple-ops-0.0.0.3-C1exc8FSLZHG2KY3jDyTct depends on tuple-ops-0.0.0.3 which failed to install. type-combinators-0.2.4.3-5vNMFCYBj1Q3v5oDQ6r4Jj failed during the building phase. The exception was: ExitFailure 1