[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 rejects valid program  |  
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Changes (by ross):

  * owner:  => ross


Comment:

 On second thoughts, I think 6.12 was right to reject
 {{{
 ite'' cA tA eA = proc x ->
   do c <- cA -< x
      (| ite_perm' (returnA -< c) |)
   where ite_perm' i = ite i tA eA
 }}}
 because the banana brackets require {{{ite_perm' :: forall env. (env ~>
 Bool) -> (env ~> r)}}}, but generalization of {{{env}}} should be blocked
 because it occurs in the types of {{{tA}} and {{{eA}}}.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5267#comment:7>
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