[GHC] #13735: RankNTypes don't work with PatternSynonyms

[GHC]

#13735: RankNTypes don't work with PatternSynonyms
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        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:  invalid           |             Keywords:
                                     |  PatternSynonyms
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by dfeuer):

 I think what you'd really want would be to have something like

 {{{#!hs
 data PLambda' = Var' (forall a. a) | ... | Lam' (forall a. a -> PLambda a)
 | ...
 }}}

 and then have some non-disgusting way to produce a function

 {{{#!hs
 convert :: Lam -> PLambda'
 }}}

 As I said, though, I don't see a nice way.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13735#comment:10>
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