[GHC] #11071: "Not in scope" errors should be more informative for qualified names.

[GHC]

#11071: "Not in scope" errors should be more informative for qualified names.
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        Reporter:  mojojojo          |                Owner:  nomeata
            Type:  feature request   |               Status:  patch
        Priority:  normal            |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.10.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D1462
       Wiki Page:                    |
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Comment (by nomeata):

 First version landed. I’ll leave this open to implement thomie’s
 suggestions (which will necessarily include a special case for this:
 {{{
 foo is not in scope.
 You have not imported anything, not even Prelude. You are on your own!
 }}}
 (The more common, new cases will be: Printing nothing if no restricted
 import exists or no restricted import exports `foo`, and the usual list
 from above if one or more restricted unqualified import could be made to
 provide `foo`.)

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11071#comment:13>
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