package01e.hs:2:1: error: Could not load module ‘Data.Map’ It is a member of the hidden package ‘containers-0.6.0.1’. You can run ‘:set -package containers’ to expose it. (Note: this unloads all the modules in the current scope.) Use -v (or `:set -v` in ghci) to see a list of the files searched for. package01e.hs:3:1: error: Could not load module ‘Data.IntMap’ It is a member of the hidden package ‘containers-0.6.0.1’. You can run ‘:set -package containers’ to expose it. (Note: this unloads all the modules in the current scope.) Use -v (or `:set -v` in ghci) to see a list of the files searched for.