[GHC] #1001: "ghc-6.6: panic! (the 'impossible' happened) interactiveUI:flush" when hiding haskell98 and importing IO

[GHC]

#1001: "ghc-6.6: panic! (the 'impossible' happened) interactiveUI:flush" when
hiding haskell98 and importing IO
----------------------------------------+-----------------------------------
 Reporter:  benjamin.franksen at bessy.de  |          Owner:  igloo         
     Type:  bug                         |         Status:  new           
 Priority:  normal                      |      Milestone:  6.6.1         
Component:  Compiler                    |        Version:  6.6           
 Severity:  normal                      |     Resolution:                
 Keywords:                              |     Difficulty:  Unknown       
 Testcase:                              |   Architecture:  x86_64 (amd64)
       Os:  Linux                       |  
----------------------------------------+-----------------------------------
Changes (by igloo):

  * milestone:  => 6.6.1
  * summary:  Failed to load interface for `IO' => "ghc-6.6: panic! (the
              'impossible' happened) interactiveUI:flush"
              when hiding haskell98 and importing IO
  * owner:  => igloo

Comment:

 Hi Ben,

 The first half of your bug report is as expected: When cabal is compiling,
 it tells GHC to hide all packages that are not explicitly listed in the
 build-depends field of the cabal file. haskell98 is exposed by default, so
 your `ghc-pkg expose haskell98` did nothing.

 However, in hiding the haskell98 package it looks like you have exposed a
 bug.
 I suspect the problem is runhaskell is trying to use IO.hFlush but is
 tripping over because the package is hidden. I'll look into it!


 Thanks
 Ian

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1001>
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