[GHC] #13155: exprIsExpandable bug

[GHC]

#13155: exprIsExpandable bug
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        Reporter:  simonpj           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       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:"9be18ea4e5cbc53ce7769a30275332d68a4ab6b9/ghc" 9be18ea/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="9be18ea4e5cbc53ce7769a30275332d68a4ab6b9"
 Fix a nasty bug in exprIsExpandable

 This bug has been lurking for ages: Trac #13155

 The important semantic change is to ensure that exprIsExpandable
 returns False for primop calls.  Previously exprIsExpandable used
 exprIsCheap' which always used primOpIsCheap.

 I took the opportunity to combine the code for exprIsCheap' (two
 variants: exprIsCheap and exprIsExpandable) with that for
 exprIsWorkFree.  Result is simpler, tighter, easier to understand.
 And correct (at least wrt this bug)!
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13155#comment:1>
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