[GHC] #11290: T6031: *** Core Lint errors : in result of Common sub-expression ***

[GHC]

#11290: T6031: *** Core Lint errors : in result of Common sub-expression ***
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        Reporter:  thomie            |                Owner:
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.11
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
                                     |  deriving/should_compile/T6031,
                                     |  deriving/should_run/T7931 (WAY=hpc)
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by nomeata):

 > I don't think the scrutinee is diverging here

 Sure it is! The error says the scrutinee is `lvl_sUi`. We have `lvl_sUb =
 case $cshowsPrec_aQD of wild_00 { }` and
 {{{
 $cshowsPrec_aQD :: Int -> Empty -> ShowS
 [LclId, Str=DmdType b]
 $cshowsPrec_aQD =
   error
     @ 'Lifted
     @ (Int -> Empty -> ShowS)
     (lvl_sU9
      `cast` (Sym (NTCo:IP[0] <"callStack">_N <CallStack>_N)
              :: CallStack ~R# (?callStack::CallStack)))
     lvl_sUa
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11290#comment:8>
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