[GHC] #12842: DatatypeContexts in data types and data families

[GHC]

#12842: DatatypeContexts in data types and data families
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        Reporter:  Iceland_jack      |                Owner:
            Type:  task              |               Status:  new
        Priority:  lowest            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Iceland_jack):

 Yeah I know they're going to be removed, I just would have thought that
 given

 {{{#!hs
 data (a ~ b) => a :~: b = Refl
 }}}

 the type of `Refl` should be `Refl :: (a ~ b) => a :~: b` similar to

 {{{#!hs
 data a :~: b where
   Refl :: a :~: a
 }}}

 I'll close

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12842#comment:2>
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