[GHC] #4012: Compilation results are not deterministic

[GHC]

#4012: Compilation results are not deterministic
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  Reporter:  kili              |          Owner:                      
      Type:  bug               |         Status:  new                 
  Priority:  high              |      Milestone:  7.6.2               
 Component:  Compiler          |        Version:  6.12.2              
Resolution:                    |       Keywords:                      
        Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple    
   Failure:  Other             |     Difficulty:  Difficult (2-5 days)
  Testcase:                    |      Blockedby:                      
  Blocking:                    |        Related:                      
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Comment(by nomeata):

 Again this is biting me. We are trying to backport a fix in warp to Debian
 testing, without having to rebuild everything based on it. And indeed the
 patch does not really change any of the exported information (e.g. no
 function eligible for inlining). But nevertheless the ABI hash changes.
 Judging from the diff of ```ghc --show-iface``` (attached), this is only
 due to renaming of internal variables.

 Maybe the ABI hashing should first alpha-normalize the expression?

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4012#comment:19>
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