[GHC] #9183: GHC shouldn't expand constraint synonyms

8 Jun 2014


      #9183: GHC shouldn't expand constraint synonyms
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       Reporter:  Feuerbach         |             Owner:
           Type:  feature request   |            Status:  new
       Priority:  normal            |         Milestone:
      Component:  Compiler          |           Version:  7.8.2
       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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 {{{
 {-# LANGUAGE ConstraintKinds #-}

 type ShowX = Show

 showX :: ShowX a => a -> String
 showX = show
 }}}

 If I now ask for the type of showX, I get:

 {{{
 *Main> :t showX
 showX :: Show a => a -> String
 }}}

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Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9183
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