[GHC] #14998: Sort out the strictness mess for exceptions

[GHC]

#14998: Sort out the strictness mess for exceptions
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        Reporter:  simonpj           |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.4.3
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:  Exceptions
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 sgraf):

 Just to sum up this thread so far:

 - Item 1 (make `catchRetry#` lazy) was merged and @dfeuer works on
 removing `ExnStr` from `Demand.hs` on `wip/no-exnstr`.
 - Item 2 was about finding out where things regress if we got rid of the
 strictness introduced in `catchException` and `catchAny`. I summarised my
 debugging sessions in [comment:16].
 - Item 3 (make `catch#` strict and see if it improves things) was handled
 in [comment:2]. Contrary to prior measurements, I couldn't make out huge
 improvements, probably due to [comment:17]. I didn't bother to pinpoint
 where the -0.1% came from, though.
 - Item 4 (IO hack) isn't fully resolved yet, but I addressed it in
 [comment:21]. @dfeuer (probably?) wrote down his thoughts on this on
 [wiki:Exceptions/PreciseExceptions#Implementingpreciseexceptions].
 - Item 5 (strictness of `raiseIO#`) is still open. I don't think I can
 address this at all, lacking too much background.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14998#comment:30>
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