[GHC] #15176: Superclass `Monad m =>` makes program run 100 times slower

[GHC]

#15176: Superclass `Monad m =>` makes program run 100 times slower
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        Reporter:  danilo2           |                Owner:  osa1
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  ⊥
       Component:  Compiler          |              Version:  8.4.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by osa1):

 * milestone:  8.8.1 => ⊥


Comment:

 Unfortunately we won't be able to get back to this for 8.8.1, and I don't
 know if this is doable in its current form so I'm removing the milestone.
 We should focus on finding a smaller reproducer as the current reproducer
 is taking forever to build and have dozens (if not hundreds) of
 dependencies (although the change we need to do is not in a dependency, it
 may still related with code generated for dependencies. In any case less
 dependencies is always better when debugging).

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15176#comment:17>
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