[GHC] #14840: QuantifiedConstraints: Can't define class alias

[GHC]

#14840: QuantifiedConstraints: Can't define class alias
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        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.5
      Resolution:  fixed             |             Keywords:
                                     |  QuantifiedConstraints wipT2893
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 simonpj):

 OK so the Description is not-a-bug.

 I don't understand comment:1.  You seem to be giving a quantified
 constraint like
 {{{
   forall (sum :: Constraint).  blah => sum
 }}}
 which asserts that for ANY constraint we can solve with this quantified
 constraint. That can't be right can it?

 I'll close this ticket, but do open a new one if you think comment:1 holds
 water somehow.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14840#comment:4>
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