[GHC] #4893: panic! the 'impossible' happened: initC: srt_lbl

[GHC]

#4893: panic! the 'impossible' happened: initC: srt_lbl
---------------------------------------+------------------------------------
    Reporter:  plc                     |        Owner:                           
        Type:  bug                     |       Status:  infoneeded               
    Priority:  normal                  |    Milestone:  7.0.2                    
   Component:  Compiler                |      Version:  7.0.1                    
    Keywords:  impossible, dcore-lint  |     Testcase:                           
   Blockedby:                          |   Difficulty:                           
          Os:  Linux                   |     Blocking:                           
Architecture:  x86                     |      Failure:  GHC rejects valid program
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Changes (by igloo):

  * status:  new => infoneeded
  * milestone:  => 7.0.2


Comment:

 Thanks for the report.

 Removing dependencies is generally more important than shortening,
 although both are useful, and shortening can make it easier to remove
 dependencies.

 One way is to make sure you have an explicit export list, and then
 iterate:
  * Pick a function (or subexpression), and replace its body with
 "undefined"
  * Delete any functions that are now warned as being used
  * Delete any imports that are now warned as being used

 If you still have any imports left, you can often replace the imported
 function `foo` with just
 {{{
 foo :: <type of foo>
 foo = undefined
 }}}

 For this sort of bug, we certainly need some sort of testcase to work on
 the bug, though.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4893#comment:2>
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