[GHC] #13668: Space leak re-introduced

[GHC]

#13668: Space leak re-introduced
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        Reporter:  simonpj           |                Owner:  (none)
            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 bgamari):

 I know precisely which commit is at fault. It was,
 {{{
 commit b3da6a6c3546562d5c5e83b8af5d3fd04c07e0c1
 Author: Ben Gamari <ben at smart-cactus.org>
 Date:   Tue May 2 11:36:47 2017 -0400

     CoreTidy: Don't seq unfoldings

     Previously we would force uf_is_value and friends to ensure that we
 didn't
     retain a reference to the pre-tidying template, resulting in a space
 leak.
     Instead, we now just reinitialize these fields (despite the fact that
 they
     should not have changed). This may result in a bit more computation,
 but most of
     the time we won't ever evaluate them anyways, so the damage shouldn't
 be so bad.

     See #13564.
 }}}

 Apparently this commit wasn't quite enough. I'm not sure how this didn't
 show up when I first tested this.

 I suppose we probably ought to revert for now.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13668#comment:1>
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