[GHC] #14626: No need to enter a scrutinised value

[GHC]

#14626: No need to enter a scrutinised value
-------------------------------------+-------------------------------------
        Reporter:  heisenbug         |                Owner:  heisenbug
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:  performance
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #13861            |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by heisenbug):

 * cc: simonpj (added)


Comment:

 @simonpj: unfortunately the `isEvaldUnfolding (idUnfolding y)` criterion
 does not hold for case scrutinees. Any idea why? I `partake`-d them and
 while some traces show up, none is `wild_*`. What s going on here?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14626#comment:2>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler