[GHC] #11974: `default` declaration doesn't allow higher-kinded types

22 Apr 2016

      #11974: `default` declaration doesn't allow higher-kinded types
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           Reporter:  goldfire       |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.1
           Keywords:                 |  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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 Since we now have #10971, I would expect the following to work:

 {{{
 {-# LANGUAGE ExtendedDefaultRules #-}

 module Bug where

 default (Maybe, [])
 }}}

 But it doesn't. Sadly, the default default list contains `[]`, but the
 user can never set this.

 Fix on the way.

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Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11974
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