[GHC] #11303: Pattern matching against sets of strings sharing a prefix blows up pattern checker

[GHC]

#11303: Pattern matching against sets of strings sharing a prefix blows up pattern
checker
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        Reporter:  bgamari           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.11
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:  T11303
      Blocked By:                    |             Blocking:
 Related Tickets:  #11302            |  Differential Rev(s):  Phab:D1716,
       Wiki Page:                    |  Phab:D1719
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Comment (by gkaracha):

 Replying to [comment:10 hvr]:
 > Mostly guessed so, because #11276 talks about exponential time, rather
 than exponential memory usage :-)

 I see. Personally, I think that all the recent bug reports concerning the
 checker were not
 strictly speaking bugs, rather improvements needed to check realistic
 code. Yet, #11276 and
 the behaviour on `text-icu-0.7.0.1` seems like an actual bug and I feel
 they have the same
 source.

 > Do you need me to provide you a smaller testcase?

 Yes, if it is not too much trouble! Even with Matthew's useful comments I
 still haven't
 found the source of #11276, maybe one more test case can shed some more
 light on this. :-)

 Thanks!

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11303#comment:13>
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