[GHC] #9103: hackage's type-level-0.2.4 fails to compile

[GHC]

#9103: hackage's type-level-0.2.4 fails to compile
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        Reporter:  slyfox            |                   Owner:
            Type:  bug               |                  Status:  closed
        Priority:  normal            |               Milestone:
       Component:  Compiler (Type    |                 Version:  7.8.2
  checker)                           |                Keywords:
      Resolution:  fixed             |            Architecture:
Operating System:  Unknown/Multiple  |  Unknown/Multiple
 Type of failure:  GHC rejects       |               Test Case:
  valid program                      |                Blocking:
      Blocked By:                    |  Differential Revisions:
 Related Tickets:  #8634             |
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Changes (by jstolarek):

 * status:  new => closed
 * resolution:   => fixed


Comment:

 Replying to [comment:13 simonpj]:
 > But as you'll see with `-fprint-explicit-kinds`, the coverage condition
 really is violated.
 I'm looking at the error message with `-fprint-explicit-kinds` and I don't
 see how the coverage condition is violated here :-/
 {{{
 Illegal instance declaration for
   ‘Add * k * (Succ k a) b (Succ k ab)’
   The liberal coverage condition fails in class ‘Add’
     for functional dependency: ‘a b -> ab’
   Reason: lhs types ‘Succ k a’, ‘b’
     do not jointly determine rhs type ‘Succ k ab’
 In the instance declaration for ‘Add (Succ a) b (Succ ab)’
 }}}
 But if you say this is correct then I trust your judgement. Closing this
 ticket.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9103#comment:14>
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