[GHC] #5168: Inaccessible branches not detected

[GHC]

#5168: Inaccessible branches not detected
-----------------------------------------------+----------------------------
  Reporter:  simonpj                           |          Owner:                  
      Type:  bug                               |         Status:  closed          
  Priority:  normal                            |      Milestone:                  
 Component:  Compiler                          |        Version:  7.0.3           
Resolution:  fixed                             |       Keywords:                  
  Testcase:  simplCore/should_compile/NoMatch  |      Blockedby:                  
Difficulty:                                    |             Os:  Unknown/Multiple
  Blocking:                                    |   Architecture:  Unknown/Multiple
   Failure:  None/Unknown                      |  
-----------------------------------------------+----------------------------
Changes (by simonpj):

  * status:  new => closed
  * testcase:  => simplCore/should_compile/NoMatch
  * resolution:  => fixed


Comment:

 In GHC 7.0 and earlier GHC treated the equational constraints generated by
 GADTs specially. In GHC 7.2 there's no need for this. I've fixed it in the
 `ghc-new-co` branch
 {{{
 commit a10a21dadac041e928ad5dab3810b68ab35bc9bb
 Author: Simon Peyton Jones <simonpj at microsoft.com>
 Date:   Wed May 4 13:27:12 2011 +0100

     Be cleverer in dataConCannotMatch, fixes Trac #5168

  compiler/basicTypes/DataCon.lhs |   11 ++++++-----
  compiler/types/Unify.lhs        |    7 +++----
  2 files changed, 9 insertions(+), 9 deletions(-)
 }}}
 and added a test.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5168#comment:1>
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