[GHC] #15426: `elemIndex` and `findIndex` still can't fuse

[GHC]

#15426: `elemIndex` and `findIndex` still can't fuse
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        Reporter:  kabuhr            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  libraries/base    |              Version:  8.4.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 Looks plausible to me. Would anyone like to submit a patch and
 (preferably) a test that demonstrates fusion.

 Please include a Note with the INLINABLE pragma to explain carefully why
 it's there.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15426#comment:1>
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