[GHC] #11558: Using Cabal 1.22 against GHC 8.0 results in unhelpful errors (was: Using Cabal 1.22 against GHC 8.0 results in terrible errors)

[GHC]

#11558: Using Cabal 1.22 against GHC 8.0 results in unhelpful errors
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        Reporter:  bgamari           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Package system    |              Version:  8.0.1-rc1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect         |  Unknown/Multiple
  warning at compile-time            |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11558#comment:3>
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