These C++11 annotations are useful for detecting programming errors. We've gained a lot of utility from these in the Chromium repo, and I've locally written plenty of bugs that these would catch.
MSVS2005, recent clangs, and GCC 4.7+ support these annotations. We should be able to define these annotations as no-ops on other compilers and still get broad coverage from developers and across the buildbots.
Created attachment 108396 [details]
Created attachment 108400 [details]
Comment on attachment 108400 [details]
Committed r95823: <http://trac.webkit.org/changeset/95823>