[GHC] #7411: Exceptions are optimized away in certain situations

[GHC]

#7411: Exceptions are optimized away in certain situations
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        Reporter:  SimonHengel       |                Owner:  tdammers
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  7.6.1
      Resolution:                    |             Keywords:  seq, deepseq,
                                     |  evaluate, exceptions
Operating System:  Linux             |         Architecture:  x86_64
                                     |  (amd64)
 Type of failure:  Incorrect result  |            Test Case:
  at runtime                         |  simplCore/should_fail/T7411
      Blocked By:                    |             Blocking:
 Related Tickets:  #5129             |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by tdammers):

 Replying to [comment:26 simonpj]:
 > I'm not sure it's worth fixing this.  It doesn't seem to be harming
 anyone, an  it's not clear how to fix it.

 OK, so here's what I think.

 Right now, the simplifier will change the behavior of programs. This is
 completely unexpected and undocumented, and it's subtle enough to make it
 all-night debugging session material. I'm a bit uncomfortable with just
 shrugging this off.

 Last resort would be to just document the problem (where?) and move on;
 but I think we should at least give the other options a fair try.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7411#comment:29>
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