[GHC] #8776: Displaying pattern synonym for a GADT

[GHC]

#8776: Displaying pattern synonym for a GADT
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       Reporter:  monoidal          |             Owner:
           Type:  bug               |            Status:  new
       Priority:  normal            |         Milestone:
      Component:  Compiler          |           Version:  7.7
       Keywords:                    |  Operating System:  Unknown/Multiple
   Architecture:  Unknown/Multiple  |   Type of failure:  None/Unknown
     Difficulty:  Unknown           |         Test Case:
     Blocked By:                    |          Blocking:
Related Tickets:                    |
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 Define

 {{{
 {-# LANGUAGE PatternSynonyms, GADTs #-}
 data A x y where
   B :: A x x

 pattern P = B
 }}}

 and in GHCi we see
 {{{
 λ> :i P
 pattern (t ~ t) => P :: A t t1  -- Defined at X.hs:5:9
 }}}

 It should be `(t ~ t1)`. Just a problem with displaying, the pattern works
 correctly.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8776>
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