[GHC] #4806: Make error message more user friendly when module is not found because package is unusable

[GHC]

#4806: Make error message more user friendly when module is not found because
package is unusable
-------------------------------------+-------------------------------------
        Reporter:  mitar             |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.0.1
      Resolution:                    |             Keywords:  newcomer
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by sgillespie):

 Agreed; however, GHC does display the same contradictory message with
 hidden packages:

 {{{
 Prelude> :m + Data.Map

 <no location info>: error:
     Could not find module ‘Data.Map’
     It is a member of the hidden package ‘containers-0.5.11.0’.
     You can run ‘:set -package containers’ to expose it.
     (Note: this unloads all the modules in the current scope.)
 }}}

 I think it would make sense to use the same language for both scenarios. I
 can either update both, or leave them both the same.  What do you think?

 In the meantime, I'm going to go ahead and submit a review so someone can
 start reviewing it

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4806#comment:28>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler