[GHC] #12130: ghc: panic! (the 'impossible' happened): find_tycon Block []

[GHC]

#12130: ghc: panic! (the 'impossible' happened): find_tycon Block []
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        Reporter:  jeiea             |                Owner:  adamgundry
            Type:  bug               |               Status:  closed
        Priority:  high              |            Milestone:  8.0.2
       Component:  Template Haskell  |              Version:  8.0.1
      Resolution:  fixed             |             Keywords:
                                     |  DisambiguateRecordFields
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash                              |            Test Case:  th/T12130
      Blocked By:                    |             Blocking:
 Related Tickets:  #11228            |  Differential Rev(s):  Phab:D2321
       Wiki Page:                    |
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Comment (by spl):

 For others who happen upon this problem with GHC 8.0.1, I've used the
 following workaround.

 In each module where the error occurs, add ```{-# LANGUAGE
 NoDisambiguateRecordFields NoRecordWildCards #-}``` and remove all uses of
 disambiguated fields and record wildcards from that module.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12130#comment:9>
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