[GHC] #9279: Local wrapper function remains in final program; result = extra closure allocation

[GHC]

#9279: Local wrapper function remains in final program; result = extra closure
allocation
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        Reporter:  simonmar          |                Owner:  simonpj
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.8.2
      Resolution:                    |             Keywords:  LateLamLift
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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Comment (by sgraf):

 Extending the existing approach by adding e.g. `| MachNullMutVar` doesn't
 work, because we still don't know which type to return in `literalType`.
 The type arguments `s` and `a` to the `MutVar#` constructor are lost. So
 there is no way around this issue unless we store `Type`s in `Literal`
 that are relevant in `Ord` and `Binary` instances.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9279#comment:19>
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