[GHC] #12506: Compile time regression in GHC 8.

[GHC]

#12506: Compile time regression in GHC 8.
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        Reporter:  deech             |                Owner:  bgamari
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      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 tdammers):

 I tried, however concatenating the relevant modules into one reduces the
 impact a bit. I'll attach a reduced version anyway, where we still get
 this:

 {{{
 -- RHS size: {terms: 8, types: 11, coercions: 1,424, joins: 0/0}
 main :: IO ()
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12506#comment:23>
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