[GHC] #2357: Implement the Haskell' proposal for polymorphic pattern bindings

[GHC]

#2357: Implement the Haskell' proposal for polymorphic pattern bindings
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  Reporter:  simonmar                                                              |          Owner:                  
      Type:  task                                                                  |         Status:  closed          
  Priority:  high                                                                  |      Milestone:  7.4.1           
 Component:  Compiler (Type checker)                                               |        Version:  6.8.2           
Resolution:  fixed                                                                 |       Keywords:                  
  Testcase:  typecheck/should_compile/T1897a, indexed_types/should_compile/T1897b  |      Blockedby:                  
Difficulty:  Unknown                                                               |             Os:  Unknown/Multiple
  Blocking:                                                                        |   Architecture:  Unknown/Multiple
   Failure:  None/Unknown                                                          |  
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Comment(by MartijnVanSteenbergen):

 It also panicks in 7.2.1. Here are the error messages:

 {{{
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.0.3 for i386-apple-darwin):
         applyTypeToArgs
     f{v ait} [lid] $dShow{v aiz} [lid]
     a{tv aiy} [sk]
 }}}

 {{{
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.2.1 for x86_64-apple-darwin):
     applyTypeToArgs
     f{v ahK} [lid] $dShow{v ahQ} [lid]
     a{tv ahP} [sk]
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2357#comment:16>
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