Resolving dependencies... Configuring base-prelude-1.0.1.1... Building base-prelude-1.0.1.1... Installed base-prelude-1.0.1.1 Downloading interspersed-0.1.1.2... Configuring interspersed-0.1.1.2... Building interspersed-0.1.1.2... Failed to install interspersed-0.1.1.2 Build log ( /home/builder/.cabal/logs/interspersed-0.1.1.2.log ): cabal: Entering directory '/tmp/cabal-tmp-7318/interspersed-0.1.1.2' Configuring interspersed-0.1.1.2... Building interspersed-0.1.1.2... Preprocessing library interspersed-0.1.1.2... [1 of 2] Compiling Interspersed.Prelude ( library/Interspersed/Prelude.hs, dist/build/Interspersed/Prelude.o ) library/Interspersed/Prelude.hs:17:1: error: Failed to load interface for ‘Control.Monad.IO.Class’ It is a member of the hidden package ‘base-4.9.0.0’. Perhaps you need to add ‘base’ to the build-depends in your .cabal file. Use -v to see a list of the files searched for. cabal: Leaving directory '/tmp/cabal-tmp-7318/interspersed-0.1.1.2' cabal: Error: some packages failed to install: interspersed-0.1.1.2 failed during the building phase. The exception was: ExitFailure 1