euterpea

I am attempting to build a project which uses Euterpea . Running stack build I get the following error, suggesting that I need to add Euterpea to the build-depends section of my .cabal file. $ sb composition-0.1.0.0: build (lib + exe) Preprocessing library composition-0.1.0.0... [2 of 2] Compiling Lib ( src/Lib.hs, .stack-work/dist/x86_64-linux-nix/Cabal-1.24.2.0/build/Lib.o ) /home/matthew/backup/composition/composition/src/Lib.hs:5:1: error: Failed to load interface for ‘Euterpea’ It is a member of the hidden package ‘Euterpea-2.0.4’. Perhaps you need to add ‘Euterpea’ to the build-depends