[[!comment format=mdwn username="stappers@eb96885816da287c29f6f699999434d532149234" nickname="stappers" avatar="http://cdn.libravatar.org/avatar/bf33450acf6fc2a17a8b4e6fc7749c65" subject="additional information" date="2017-12-28T12:44:23Z" content=""" There was another error before the error reported above. It was Error: While constructing the build plan, the following exceptions were encountered: In the dependencies for secret-project-0.0: threepenny-gui-0.7.0.1 from stack configuration does not match (==0.8.0.0) (latest matching version is 0.8.0.0) needed since secret-project is a build target. My workaround was --- a/secret-project.cabal +++ b/secret-project.cabal @@ -21,7 +21,7 @@ Executable propellor-config Build-Depends: base (>= 4.9 && < 5.0) , propellor >= 4.7.6 - , threepenny-gui (== 0.8.0.0) + , threepenny-gui (== 0.7.0.1) , random (>= 1.1) , random-shuffle (>= 0.0.4) , filepath (>= 1.4) That because `stack.yaml` has a package line - http://github.com/joeyh/threepenny-gui/archive/59242cf93bdb8eaa805f5c2b0241e9a1cba9a70f.zip where I think/assume the 0.7.0.1 comes from. """]]