[GHC] #9630: compile-time performance regression (probably due to Generics)

[GHC]

#9630: compile-time performance regression (probably due to Generics)
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        Reporter:  hvr               |                Owner:  simonpj
            Type:  bug               |               Status:  patch
        Priority:  high              |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.9
      Resolution:                    |             Keywords:  deriving-perf
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #9583, #10293     |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 Thank you for helping to characterise this. More please!  Eg is it the
 type checker, or all the way down the pipeline?  Do terms get big?  Why
 does putting Binary's classes in the file help?  Why does removing `not-
 used` help.

 One possible reason: see [http://research.microsoft.com/en-
 us/um/people/simonpj/papers/variant-f/index.htm Scrap your type
 applications] Section 2.3.  Generics, I suspect, uses lots of nested
 types!

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9630#comment:25>
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