RE: Error messages when mixing profiled and unprofiled code

> I just went through an interesting (== painful) remote debugging
> session with one of my clients which could be avoided by improving 
> an error message.
> 
> If you compile a program for profiling but don't have profiling
> versions of the standard libraries, then the linker generates reports
> like:
> 
>   ghc-5.04.1: can't find module `List' (while processing 
> "./../Flattener.hs")
> 
> This is utterly baffling since:
> 
> 1) It is unthinkable that a standard GHC installation would 
> lack 'List'
> 2) The code compiles fine on other machines (which I later realised
>    had the profiling libs installed).
> 
> A much better error message would be:
> 
>   ghc-5.04.1: can't find profiling version of module `List' 
> (while ...)
>                          ^^^^^^^^^^^^^^^^^^^^

It wasn't convenient to do exactly what you wanted here, but we agree
there's a problem.  So I added the option to print out all the filenames
that the compiler was searching for in the event that it can't find an
interface file or source file.  To get this information you just add the
-v option (the error message mentions this if you don't add -v).

Cheers,
        Simon