[GHC] #9765: Strange behavior of GC under ghci

[GHC]

#9765: Strange behavior of GC under ghci
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              Reporter:  remdezx     |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  GHCi        |          Version:  7.8.3
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:  Incorrect   |       Blocked By:
  result at runtime                  |  Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by rwbarton):

 > Why is there a difference between doing it with `do` notation and with
 `let` binding?

 Well, this part is easy: the `let` binding is generalized over the type of
 the numeric literal `1`, so that `a` is really a function that constructs
 a new Map and a new ForeignPtr each time it is called (evaluated). The
 result in the `do` notation is not generalized, and is really a Map.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9765#comment:1>
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