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     ghc-tcplugins-extra-0.3
Building     ghc-tcplugins-extra-0.3
Completed    ghc-tcplugins-extra-0.3
Starting     ghc-typelits-natnormalise-0.6.2
Building     ghc-typelits-natnormalise-0.6.2
Completed    ghc-typelits-natnormalise-0.6.2
Starting     ghc-typelits-knownnat-0.6
Building     ghc-typelits-knownnat-0.6
Completed    ghc-typelits-knownnat-0.6
Starting     modular-0.1.0.2
Building     modular-0.1.0.2
Failed to install modular-0.1.0.2
Build log ( /home/builder/.cabal/logs/ghc-8.6.1/modular-0.1.0.2-8aDnaqcb9aI7wsAxFlQr6N.log ):
cabal: Entering directory '/tmp/cabal-tmp-24403/modular-0.1.0.2'
Configuring modular-0.1.0.2...
Preprocessing library for modular-0.1.0.2..
Building library for modular-0.1.0.2..

src/Numeric/Modular.hs:54:43: error: parse error on input ‘*’
   |
54 | import GHC.TypeLits (Nat, KnownNat, type (*), type (+), natVal)
   |                                           ^
cabal: Leaving directory '/tmp/cabal-tmp-24403/modular-0.1.0.2'
cabal: Error: some packages failed to install:
modular-0.1.0.2-8aDnaqcb9aI7wsAxFlQr6N failed during the building phase. The
exception was:
ExitFailure 1