[GHC] #13156: CSE missing an easy case

[GHC]

#13156: CSE missing an easy case
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        Reporter:  simonpj           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.0.1
      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 Simon Peyton Jones <simonpj@…>):

 In [changeset:"b78fa759bfb405e3dc20d5e4bbb088989d17eb8b/ghc"
 b78fa759/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="b78fa759bfb405e3dc20d5e4bbb088989d17eb8b"
 Simplify and improve CSE

 Trac #13156 showed a lost opportunity for CSE. I found that it was
 easy to fix, and it had the nice side effect of rendering a previous
 nasty case, described in Note [Corner case for case expressions],
 unnecessary.

 Simpler code, does more.  Great.
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13156#comment:1>
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