[GHC] #11666: Severe performance degradation in GHC 8.0.1 compared to GHC 7.10.x

[GHC]

#11666: Severe performance degradation in GHC 8.0.1 compared to GHC 7.10.x
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        Reporter:  mrkkrp            |                Owner:
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1-rc2
      Resolution:  invalid           |             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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Changes (by rwbarton):

 * status:  new => closed
 * resolution:   => invalid


Comment:

 This is due to
 https://github.com/haskell/filepath/commit/dd13bb32b7b563248fa2bfa232891e05759d6506
 and the generate-and-check strategy used in the `Arbitrary EntrySelector`
 instance (and maybe others). That will almost never work now for long
 paths that `Windows.isValid` recognizes more characters as invalid.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11666#comment:9>
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