[GHC] #7828: RebindableSyntax and Arrow

[GHC]

#7828: RebindableSyntax and Arrow
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        Reporter:  AlessandroVermeulen        |            Owner:
            Type:  bug                        |  jstolarek
        Priority:  normal                     |           Status:  new
       Component:  Compiler (Type checker)    |        Milestone:  7.10.1
      Resolution:                             |          Version:  7.6.2
Operating System:  Unknown/Multiple           |         Keywords:
 Type of failure:  GHC rejects valid program  |     Architecture:
       Test Case:                             |  Unknown/Multiple
        Blocking:                             |       Difficulty:  Unknown
                                              |       Blocked By:
                                              |  Related Tickets:
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Comment (by jstolarek):

 Thanks Ross. I think I still don't understand the stk thing. What are the
 "anonymous inputs to the arrow"? Is that described in any of the arrow
 papers?

 > The simplifier reduces that to an identity using rules in Control.Arrow

 How can I observe that? Using `-ddump-simpl` only shows that this huge
 expression is split into many smaller functions but it doesn't look like
 anything gets simplified. Using `-ddump-rules` and `-ddump-rule-rewrites`
 I see that some rules fire but none of them seems to optimize the above
 expression.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7828#comment:15>
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