[GHC] #13893: Improved Help for Control.Concurrent and Control.Exception when "variable not in scope"

[GHC]

#13893: Improved Help for Control.Concurrent and Control.Exception when "variable
not in scope"
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        Reporter:  vanto             |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Poor/confusing    |  Unknown/Multiple
  error message                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by slyfox):

 * cc: slyfox (added)


Comment:

 I have a few clarifying questions on this proposal.

 - Why take preference of packages coming with ghc in this case?

   It's not always the case that user wants to use '''base''''s primitives.

   I would say suggesting incorrect module imports would lead to more
 confusion.

 - Which procedure should define which packages (and modules) are blessed
   to deliver suggestions for symbols?

   For example, do '''xhtml''' or '''haskeline'' packages quialify as such?

 - As ticket's subject is worded why '''Control.Concurrent''' and
 '''Control.Exception''' should be threated special?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13893#comment:4>
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