[GHC] #11270: "Unusable UNPACK pragma" warnings should be printed even without -O

[GHC]

#11270: "Unusable UNPACK pragma" warnings should be printed even without -O
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        Reporter:  osa1              |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.11
      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 osa1):

 > Are you saying that you want GHC to do all the checks that it would have
 done if it had been optimising, even though it will then ignore the
 results?

 Yes! In my opinion -Wall should check for all the warnings, no matter
 which optimization setting is used. Why? Because in my experience, this
 happens a lot: Programs are developed with -O0 or a similar parameter that
 reduces compilation times, to be able to iterate faster. Then programs
 would be compiled with -O before distribution (or before testing etc.).

 Currently what happens is you develop a program using -O0, but just when
 you think you're done and you can move to the testing you start getting
 warnings. This is very annoying IMO.

 We can improve the warning messages by maybe saying something like:
 "Unusable UNPACK ... Note that UNPACK pragmas are only effective with -O
 or higher". (the second part is only printed in -O0)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11270#comment:2>
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