Haskell - GHC error: Could not find module ‘Prelude’/ Perhaps you haven't installed the profiling libraries for package ‘base-4.12.0.0’?

Question

I've just installed haskell-platform from the Ubuntu repositories (it comes with GHC version 8.6.5 ) as instructed by the website . Now, upon trying to compile a program for profiling, using ghc -O2 -prof myCode.hs , I'm met with the following error message:

myCode.hs:1:1: error: 
    Could not find module ‘Prelude’
    Perhaps you haven't installed the profiling libraries for package ‘base-4.12.0.0’?

and similarly for the System.IO module.

Should they not come with the default Haskell instalation? How can I proceed? Perhaps I should purge it all and get Haskell form another source ( Stack , Ghcup , etc? Should it matter?)

I'm fairly new to this, so any help is appreciated.

Answer 1

On Ubuntu, essentially all of the Haskell packages come in bland and -prof flavors. You need the latter for profiling.

ghcup is also fine. There's no need to purge it all -- ghcup and the package manager can coexist cleanly.