[GHC] #6124: Spurious non-exhaustive warning with GADT and newtypes

[GHC]

#6124: Spurious non-exhaustive warning with GADT and newtypes
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    Reporter:  joeyadams                |       Owner:                                   
        Type:  bug                      |      Status:  new                              
    Priority:  normal                   |   Milestone:                                   
   Component:  Compiler (Type checker)  |     Version:  7.4.1                            
    Keywords:                           |          Os:  Unknown/Multiple                 
Architecture:  Unknown/Multiple         |     Failure:  Incorrect warning at compile-time
  Difficulty:  Unknown                  |    Testcase:                                   
   Blockedby:                           |    Blocking:                                   
     Related:                           |  
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Changes (by simonpj):

  * difficulty:  => Unknown


Comment:

 Thanks.  I'm afriad this is part of a collection of pattern-match-
 exhaustiveness-checking tickets: #595, #5728, #3927, #5724, #5762, #4139.
 I think it's precisely #3927 but have not checked carefully.

 This whole area needs love, but it's not trivial or I'd have done it by
 now!

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6124#comment:1>
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