I hit this when compiling taffybar module. It is very strange that actually claim that I need load this hidden module, which is itself. Error msgs are below:
[~/Public/taffybar]-[myMaster↓]── - rm -rf ~/.cache/taffybar && taffybar
Configuration '/home/jethros/.config/taffybar/taffybar.hs' changed.
Recompiling.
Error occurred while loading configuration file.
Error:
/home/jethros/.config/taffybar/taffybar.hs:26:1: error:
Failed to load interface for ‘System.Taffybar.ToggleMonitor’
It is a member of the hidden package ‘taffybar-0.4.6’.
Use -v to see a list of the files searched for.