[GHC] #8569: ASSERT in testcase type-rep, only in some ways:

[GHC]

#8569: ASSERT in testcase type-rep, only in some ways:
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        Reporter:  nomeata           |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  Test Suite        |          Version:  7.7
      Resolution:                    |         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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Comment (by nomeata):

 Minimalizing the example yields

 {{{
 module Example (x) where

 data Rep t where
   Rint :: Rep Int
   Rdata :: Rep i -> (t -> i) -> (i -> t) -> Rep t

 addUp :: Rep a -> a -> Int
 addUp Rint          n         = n
 addUp (Rdata i f g) x         = addUp i (f x)

 x = addUp undefined [1]
 }}}

 Again, the problem only occurs with `-O`.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8569#comment:3>
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