Ticket #861 (closed bug: fixed)
-prof without profiling libraries fails without explanation
Compiling with -prof caused ghc to fail on the first import, claiming that the module to be imported could not be found (it worked perfectly without -prof).
Initialliy I thought the -prof was just plain buggy. After a while I realised the real reason was that the profiling library package was not installed.
The bug here is a lack of error report by the compiler. Something like "Profile libraries not found". Instead, the way it fails is totally unrelated to the cause.