warnings under Xcode 6.1.1 (probably with -Weverything) #96

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1. dixlorenz commented on Feb 6, 2015

   

   dixlorenz

   on Feb 6, 2015

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   one more: in Result visit(const Arg &arg) clang complains about the fallthrough in release mode and suggests inserting [[clang::fallthrough]]. This gives a warning in debug mode though, because after the assert(false) it is unreachable code.
2. vitaut

   added 2 commits that reference this issue on Feb 7, 2015

   Fix by @dixlorenz for clang warnings "'return' will never be executed" (

   ...

   37ad436

   Try detecting clang::fallthrough using __has_cpp_attribute

   ...

   d7fea1b
3. vitaut

   closed this as completedon Feb 7, 2015
4. vitaut commented on Feb 8, 2015

   

   vitaut

   on Feb 8, 2015

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   Reopening until the fallthrough warning is resolved.
5. vitaut

   reopened this on Feb 8, 2015
6. vitaut commented on Feb 8, 2015

   

   vitaut

   on Feb 8, 2015

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   @dixlorenz Could you please check if the fix in branch fallthrough resolves the fallthrough warning? I tried detecting the availability of [[clang::fallthrough]] based on clang version there (you might need to change 600 to your version in https://github.com/cppformat/cppformat/blob/fallthrough/format.h#L124 if it is lower).
7. dixlorenz commented on Feb 8, 2015

   

   dixlorenz

   on Feb 8, 2015

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   Almost perfect. It resolves the fallthrough warning, but in debug build I now get

   warning: fallthrough annotation in unreachable code

   because of the assert(false)... Somewhat interestingly (to me): this code

   default:
     assert(false);
     return FMT_DISPATCH(visit_int(arg.int_value));
   case Arg::INT:
     return FMT_DISPATCH(visit_int(arg.int_value));
   

   does not give a warning about unreachable code (or any other).

   That might be the easiest/cleanest solution. It does have the same semantics as the fallthrough and doesn't need macros, #ifdefs or rely on the compiler or its version at all.
8. vitaut commented on Feb 9, 2015

   

   vitaut

   on Feb 9, 2015

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   So does this commit fixes the warnings? (I used your suggestion but simplified it a bit since there is no need to dispatch there.) If it works I'll merge it into master and remove the fallthrough attribute detection.
   Thanks!
9. dixlorenz commented on Feb 9, 2015

   

   dixlorenz

   on Feb 9, 2015

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   That works perfectly, no warning, neither in debug or in release.
10. vitaut commented on Feb 9, 2015

    

    vitaut

    on Feb 9, 2015

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    Closing the issue via 04a21bb then. Thanks again for your help.
11. vitaut

    closed this as completedon Feb 9, 2015