[GHC] #15528: Match is missing a Data instance

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Thu Aug 16 09:14:49 UTC 2018


#15528: Match is missing a Data instance
-------------------------------------+-------------------------------------
           Reporter:  mpickering     |             Owner:  (none)
               Type:  task           |            Status:  new
           Priority:  normal         |         Milestone:  8.6.1
          Component:  Compiler       |           Version:  8.4.3
           Keywords:  newcomer       |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 If I try to use `showAstData` on a `Match` then GHC complains that there
 is no
 Data instance.

 {{{
 No instance for (Data (Expr.Match p (Expr.LHsExpr p)))
 }}}

 It seems that all the constituent parts of `Match` have a `Data` instance
 so `Match` should as well.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15528>
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