To reproduce git clone https://github.com/ndmitchell/hoogle and in stack repl:
λ > :l src/Hoogle.hs
[ 1 of 27] Compiling Input.Settings ( src/Input/Settings.hs, interpreted )
src/Input/Settings.hs:17:1: error:
Failed to load interface for ‘Paths_hoogle’
Use -v to see a list of the files searched for.
Failed, modules loaded: none.
This seems to be caused by Paths_hoogle being a hidden-modules but I do not know what the solution is to get src/Hoogle.hs to load.