[GHC] #5267: Arrow command combinators

[GHC]

#5267: Arrow command combinators
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  Reporter:  peteg                        |          Owner:  ross            
      Type:  bug                          |         Status:  new             
  Priority:  normal                       |      Milestone:  7.4.1           
 Component:  Compiler                     |        Version:  7.0.3           
Resolution:                               |       Keywords:                  
  Testcase:                               |      Blockedby:                  
Difficulty:                               |             Os:  Unknown/Multiple
  Blocking:                               |   Architecture:  Unknown/Multiple
   Failure:  GHC accepts invalid program  |  
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Comment(by simonpj):

 I'm sorry I just don't understand the typing rules for arrow syntax,
 especially this bit about arrow forms with a nested tuple type whose depth
 is unknown.  Where can I find them written down?  They aren't in the
 original paper.

 Somehow we have to fix the type checking code for arrow forms; as it
 stands it is simply wrong and will fail unpredictably.  But I don't
 undersand it well enough to fix it.  Do you understand the problem, Ross?
 Can you fix it? Or should we talk by phone?

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5267#comment:17>
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