[Bug c/7652] -Wswitch-break : Warn if a switch case falls through

[manu at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=7652

--- Comment #31 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
(In reply to Florian Weimer from comment #30)
> (In reply to Manuel López-Ibáñez from comment #29)
> 
> > I like the previous suggestion of using "goto LABEL;". In fact, the warning
> > message could explicitly say "use %<goto %D;%> to silence this warning".
> 
> Does this mean that you propose a GCC extension which allows to write this?
> 
>      goto 5;
>    case 5:

Sorry, ignore my comment. I am not sure what I was thinking....

__builtin_fallthrough() seems fine enough. It could be mentioned by the warning
message. But as you said, it would be better to detect as many false positives
as possible to avoid forcing people to use the __builtin work-around.