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     cabal-doctest-1.0.6
Building     call-stack-0.1.0
Building     base-orphans-0.8
Completed    call-stack-0.1.0
Starting     colour-2.3.4
Completed    base-orphans-0.8
Starting     hashable-1.2.7.0
Completed    StateVar-1.1.1.1
Starting     haskell-lexer-1.0.2
Building     colour-2.3.4
Building     hashable-1.2.7.0
Building     haskell-lexer-1.0.2
Completed    cabal-doctest-1.0.6
Starting     hw-int-0.0.0.3
Building     hw-int-0.0.0.3
Completed    hw-int-0.0.0.3
Starting     hw-string-parse-0.0.0.4
Building     hw-string-parse-0.0.0.4
Completed    hashable-1.2.7.0
Starting     mmap-0.5.9
Building     mmap-0.5.9
Completed    hw-string-parse-0.0.0.4
Starting     parallel-3.2.2.0
Building     parallel-3.2.2.0
Completed    mmap-0.5.9
Starting     primitive-0.6.4.0
Completed    colour-2.3.4
Starting     random-1.1
Building     primitive-0.6.4.0
Building     random-1.1
Completed    parallel-3.2.2.0
Starting     reflection-2.1.4
Building     reflection-2.1.4
Completed    random-1.1
Starting     safe-0.3.17
Building     safe-0.3.17
Completed    reflection-2.1.4
Starting     semigroups-0.18.5
Building     semigroups-0.18.5
Completed    safe-0.3.17
Starting     tagged-0.8.6
Building     tagged-0.8.6
Completed    semigroups-0.18.5
Starting     terminal-size-0.3.2.1
Building     terminal-size-0.3.2.1
Completed    terminal-size-0.3.2.1
Starting     th-abstraction-0.2.10.0
Completed    tagged-0.8.6
Starting     transformers-compat-0.6.2
Building     th-abstraction-0.2.10.0
Completed    haskell-lexer-1.0.2
Starting     unliftio-core-0.1.2.0
Building     transformers-compat-0.6.2
Building     unliftio-core-0.1.2.0
Completed    primitive-0.6.4.0
Starting     void-0.7.2
Building     void-0.7.2
Completed    unliftio-core-0.1.2.0
Starting     wl-pprint-annotated-0.1.0.1
Completed    void-0.7.2
Starting     contravariant-1.5
Building     wl-pprint-annotated-0.1.0.1
Building     contravariant-1.5
Completed    transformers-compat-0.6.2
Starting     unordered-containers-0.2.9.0
Building     unordered-containers-0.2.9.0
Completed    th-abstraction-0.2.10.0
Starting     async-2.2.1
Building     async-2.2.1
Completed    contravariant-1.5
Starting     ansi-terminal-0.8.2
Completed    wl-pprint-annotated-0.1.0.1
Starting     distributive-0.6
Building     ansi-terminal-0.8.2
Completed    async-2.2.1
Starting     pretty-show-1.9.5
Failed to install pretty-show-1.9.5
Build log ( /home/builder/.cabal/logs/ghc-8.6.3/pretty-show-1.9.5-4s9IVBWSe01IF3L4DDRCg8.log ):
cabal: Entering directory '/tmp/cabal-tmp-32674/pretty-show-1.9.5'
Configuring pretty-show-1.9.5...
cabal: The program 'happy' is required but it could not be found.

cabal: Leaving directory '/tmp/cabal-tmp-32674/pretty-show-1.9.5'
Starting     vector-0.12.0.2
Building     vector-0.12.0.2
Building     distributive-0.6
Completed    ansi-terminal-0.8.2
Completed    distributive-0.6
Completed    unordered-containers-0.2.9.0
Completed    vector-0.12.0.2
cabal: Error: some packages failed to install:
hedgehog-0.6.1-Ce0bxlllbpTGteSUtemwgk depends on hedgehog-0.6.1 which failed
to install.
hw-dsv-0.3.4-KYJzDPrg8FjHKNp5leU67G depends on hw-dsv-0.3.4 which failed to
install.
pretty-show-1.9.5-4s9IVBWSe01IF3L4DDRCg8 failed during the configure step. The
exception was:
ExitFailure 1