[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:  closed
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.11
      Resolution:  fixed             |                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 Joachim Breitner <mail@…>):

 In [changeset:"6cf0c7962c582eefb84cdf2735504d034fb16314/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="6cf0c7962c582eefb84cdf2735504d034fb16314"
 Some stress tests for the empty case linter

 This is a variation of T2431 where the emptyness of the type is hidden
 behind a newtype, a type family and a closed type family. In all cases,
 it would be sound for the compiler to determine that the equality type
 is empty and the case alternatives may be dropped.

 At the moment, GHC does _not_ determine that. But if it ever does, this
 test ensures that we do not forget to make the lint from #10180 smarter
 as well.
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10180#comment:20>
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