[GHC] #11195: New pattern-match check can be non-performant

[GHC]

#11195: New pattern-match check can be non-performant
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        Reporter:  goldfire          |                Owner:  goldfire
            Type:  bug               |               Status:  closed
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.11
      Resolution:  fixed             |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash                              |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D1676
       Wiki Page:                    |
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Changes (by bgamari):

 * status:  new => closed
 * differential:   => Phab:D1676
 * resolution:   => fixed


Comment:

 The above patch teaches the pattern checker to run the patterns which it
 will check through a heuristic to determine whether it may result in the
 blow-up documented in this ticket. If there is a good chance things will
 explode the checker will run a simplified, but more performant, check.
 This should prevent this issue from affecting users in most cases.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11195#comment:7>
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