[GHC] #15832: returnIO/bindIO destroys runtime explicit stack information in some cases

[GHC]

#15832: returnIO/bindIO destroys runtime explicit stack information in some cases
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        Reporter:  infinity0         |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.6.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by infinity0):

 Some more examples:

 Good:

 {{{#!hs
 data X = X Int deriving (Eq, Show)

 main :: IO ()
 main = do
   return undefined
   print $ X (error "XXX")
 }}}

 Bad:

 {{{#!hs
 data X = X Int deriving (Eq, Show)

 main :: IO ()
 main = do
   _ <- return undefined
   print $ X (error "XXX")
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15832#comment:1>
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