[GHC] #13080: Memory leak caused by nested monadic loops

[GHC]

#13080: Memory leak caused by nested monadic loops
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        Reporter:  Feuerbach         |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.0.1
      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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Comment (by nomeata):

 In the blog post you write

 > Let’s change (“eta-expand”) the poll code as if then had arity 4,
 without actually changing then or thenIO or their runtime arities:

 and that this fixes the space leak. Isn’t this eta-expansion exactly what
 the state hack is about? So why does it not not work here? Ah, becuase
 `poll` is not at type `IO a` but rather for an arbitrary `Monad`… yeah,
 then it’s harder.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13080#comment:11>
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