[GHC] #10176: Invalid core generated with GHC 7.10 RC3

[GHC]

#10176: Invalid core generated with GHC 7.10 RC3
-------------------------------------+-------------------------------------
              Reporter:              |             Owner:
  NeilMitchell                       |            Status:  new
                  Type:  bug         |         Milestone:
              Priority:  high        |           Version:  7.8.4
             Component:  Compiler    |  Operating System:  Unknown/Multiple
              Keywords:              |   Type of failure:  None/Unknown
          Architecture:              |        Blocked By:
  Unknown/Multiple                   |   Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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 Using the Shake repo (https://github.com/ndmitchell/shake.git) at commit
 d7fa04 and GHC 7.10 RC3 or GHC HEAD, if I {{cabal test}} I get the error:

 {{{
 ## BUILD oracle --quiet *str-int
 TESTS FAILED
 shake-test: Expected an exception but succeeded
 }}}

 Discussion about this issue can be found on the mailing list:
 http://osdir.com/ml/general/2015-03/msg25847.html

 GHC generates the Core:

 {{{
 case (\_ -> error "here") of {}
 }}}

 This is invalid GHC Core. I intend to track down a minimal example
 shortly.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10176>
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