[GHC] #12158: ghc: panic! (the 'impossible' happened) translateConPatVec: lookup

[GHC]

#12158: ghc: panic! (the 'impossible' happened)  translateConPatVec: lookup
-------------------------------------+-------------------------------------
        Reporter:  wozgonon          |                Owner:  gkaracha
            Type:  bug               |               Status:  closed
        Priority:  high              |            Milestone:  8.4.2
       Component:  GHCi              |              Version:  8.0.1
      Resolution:  duplicate         |             Keywords:
                                     |  PatternMatchWarnings
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash                              |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #13644            |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by philderbeast):

 I tried verifying this in place by updating stack to use
 [[https://gist.github.com/DanBurton/ba6fcf6b54491436fe8c98d2b2dc702b|ghc-8.4.1-alpha2]].
 I set `allow-newer: true` and then hit problems with libraries that I
 worked through by adding specific packages references until I hit `refex-
 tdfa` that doesn't compile with this version of ghc.

 {{{
 - location:
     git: https://github.com/haskell/primitive.git
     commit: 53f72ce69a4dfde5345cf5809a8b4a1993523367
   extra-dep: true
 - location:
     git: https://github.com/haskell/text.git
     commit: 9fac5db9b048b7d68fa2fb68513ba86c791b3630
   extra-dep: true
 - location:
     git: https://github.com/ChrisKuklewicz/regex-tdfa
     commit: f1b671946ee573f86d72484f3ab56487d456e735
 }}}

 I think it may be better to try to get a minimal test case going with
 fewer dependencies.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12158#comment:16>
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