[GHC] #13990: Core Lint error on empty case

[GHC]

#13990: Core Lint error on empty case
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        Reporter:  mbieleck          |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.2.2
       Component:  Compiler          |              Version:  8.2.1-rc3
      Resolution:                    |             Keywords:  core-lint
                                     |  case
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by nomeata):

 > this ticket has convinced me that it's not special afte all.

 I wholehartedly agree with removal of this check (The second check was an
 error originally, we had to downgrade it to warning because of false
 positives, and now even that is not good enough.) I think it is inevitable
 that we will have some transformations making choices that – after some
 other transformations – are no longer verifiable by CoreLint.

 (Incidentally, this also means that we have transformations in GHC that
 produce non-well-typed Core, if we consider “well-typed” to mean “we can
 prove progress and preservation”. This is not a shortcoming of GHC, but
 rather of the notion of well-typedness, though.)

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13990#comment:10>
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