[GHC] #2378: panic: lookupVers1, when standalone deriving Typeable and Data

[GHC]

#2378: panic: lookupVers1, when standalone deriving Typeable and Data
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 Reporter:  guest     |          Owner:  simonpj
     Type:  bug       |         Status:  new    
 Priority:  normal    |      Milestone:         
Component:  Compiler  |        Version:  6.8.3  
 Severity:  normal    |     Resolution:         
 Keywords:            |     Difficulty:  Unknown
 Testcase:            |   Architecture:  x86    
       Os:  MacOS X   |  
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Comment (by simonpj):

 Nice program.  You revealed at least three bugs in the implementation of
 standalone deriving, and that's without counting the `lookupVers1`
 problem, which doesn't show up in HEAD.

 So I've fixed all of them in the HEAD.  Since we've pushed 6.8.3 out now,
 we've missed the boat on that.  If we ever release 6.8.4 we should put the
 patch in:
 {{{
 Tue Jul  1 13:09:08 BST 2008  simonpj at microsoft.com
   * Several fixes to 'deriving' including Trac #2378
 }}}
 There's no good workaround for 6.8.3 except not to use standalone
 deriving. Also doing this:
 {{{
 newtype T f = ... deriving( Typeable1 )
 }}}
 seems unfixably broken in 6.8.3 I'm afraid.  I think you may have to use a
 data type instead.

 Thanks for bringing all this to light.

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2378#comment:4>
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