Fix rb_warn and rb_warning macros

[chrisseaton]

These can't have a ; at the end of them - think of the case:

if (...)
    rb_warn(...);
else
    ...

This won't work with the ;; you'll get before the else.

The change in byebug: deivid-rodriguez/byebug@v11.0.1...v11.1.0#diff-cba2d7f9da55366f27f120efb50dbb19R364

Much of the Ruby ecosystem seems to be broken without this fix.

Shopify#1

[nirvdrum]

@chrisseaton The byebug link you provided shows an empty set of changes.

[chrisseaton]

GitHub seems to break the link as Markdown. Try:

https://github.com/deivid-rodriguez/byebug/compare/v11.0.1...v11.1.0#diff-cba2d7f9da55366f27f120efb50dbb19R364

Even then the line link is broken - doesn't show the right place but does highlight it...

[eregon]

Could we use __extension__({ \ for this? I'm not sure if it would be better than do/while(0) which also seems a few times in ruby.h.

[eregon]

We should add some kind of check to not make this mistake again. Maybe simply a grep in tool/lint.sh?

[aardvark179]

I think we can reasonable convert them to __extension__ based macros, and they will probably be slightly less fragile.

I think there is a warning we can switch on in clang to help catch this.

[eregon]

@chrisseaton Thanks for the fix!
@aardvark179 Could you integrate it?