[GHC] #9198: large performance regression in type checker speed in 7.8

[GHC]

#9198: large performance regression in type checker speed in 7.8
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        Reporter:  carter            |                Owner:
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.2.1
       Component:  Compiler (Type    |              Version:  7.8.2
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 The trouble here is that we don't have even a partial solution in mind.
 Ideas welcome.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9198#comment:9>
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