[GHC] #12471: Weirdness when using quosiquoter in pattern synonyms / GADT context

[GHC]

#12471: Weirdness when using quosiquoter in pattern synonyms / GADT context
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        Reporter:  Iceland_jack      |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
                                     |  TemplateHaskell, PatternSynonyms,
                                     |  GADTs
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 Iceland_jack):

 It also works if I omit the type signature of `MkI` resulting in the
 inferred type

 {{{
 >>> :i MkI
 pattern MkI :: () => t GHC.Prim.~# Int => Int -> Exp t
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12471#comment:1>
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