[GHC] #9872: Runing type functions is too slow

[GHC]

#9872: Runing type functions is too slow
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              Reporter:  simonpj     |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.8.3
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:              |       Blocked By:
  None/Unknown                       |  Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by goldfire):

 Recall that `normaliseType` does "deep" normalisation, not just at top
 level -- it recursively tries to normalise all arguments. And, I don't
 think it would take long for it to try. If `normaliseType` doesn't remove
 a top-level type function, then flatten as normal, but it's still possible
 some good progress was made below top level.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9872#comment:7>
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