[GHC] #8809: Prettier error messages?

[GHC]

#8809: Prettier error messages?
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        Reporter:  joelteon          |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.9
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
  #8809,#10073,#10179                |
       Wiki Page:                    |
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Comment (by Rufflewind):

 Replying to [comment:38 dobenour]:
 > I don't guess that the ''extremely'' hackish approach of using
 `unsafeInterleaveIO` would work here?  The IO action (reading from a file)
 clearly need not be performed if its result is not used, and we can force
 it to happen by using `deepSeq` at the appropriate point (to make sure the
 `SDoc` is fully evaluated).
 >
 > That would avoid needing the `SDoc` to contain an `IO` action at the
 expense of using unsafe code.

 I found a cleaner workaround for the problem, so IO actions in SDocs are
 no longer necessary.  https://phabricator.haskell.org/D2718

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8809#comment:39>
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