[GHC] #8968: Pattern synonyms and GADTs

[GHC]

#8968: Pattern synonyms and GADTs
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        Reporter:  kosmikus                   |            Owner:  cactus
            Type:  bug                        |           Status:  new
        Priority:  normal                     |        Milestone:
       Component:  Compiler (Type checker)    |          Version:
      Resolution:                             |  7.8.1-rc2
Operating System:  Unknown/Multiple           |         Keywords:  pattern
 Type of failure:  GHC rejects valid program  |  synonyms
       Test Case:                             |     Architecture:
        Blocking:                             |  Unknown/Multiple
                                              |       Difficulty:  Unknown
                                              |       Blocked By:
                                              |  Related Tickets:
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Changes (by cactus):

 * owner:   => cactus


Comment:

 I have started working on adding pattern synonym signatures, in the branch
 `wip/T8968`. So far, it seems I will have to go with a syntax like


 {{{
    pattern type Eq b => Single a Bool b :: Num a => T a
 }}}

 instead of

 {{{
    pattern Eq b => Single a Bool b :: Num a => T a
 }}}

 to make parsing unambiguous between pattern synonym definitions and
 pattern synonym signatures.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8968#comment:21>
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