[GHC] #10180: Lint check: Empty alternatives imply bottoming scrutinee

[GHC]

#10180: Lint check: Empty alternatives imply bottoming scrutinee
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        Reporter:  nomeata           |                   Owner:  nomeata
            Type:  task              |                  Status:  infoneeded
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.11
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
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Comment (by simonpj):

 Replying to [comment:2 nomeata]:
 > So there is a lambda under the case, but it is a type lambda. Bogus or
 not?

 Ha!  There's a missing case in `exprIsBottom`:
 {{{
 exprIsBottom (Lam v e) | isTyVar v = exprIsBottom e
 }}}
 Well spotted.

 Simon

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10180#comment:4>
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