Tests 021, 024, 031, and 033 in http://hg.csswg.org/test/file/5f94e4b03ed9/contributors/opera/submitted/css3-conditional fail because there's no explicit error recovery in @support's grammar. Opera and Firefox pass the tests.
Created attachment 177349 [details]
Created attachment 184040 [details]
Comment on attachment 184040 [details]
Clearing flags on attachment: 184040
Committed r142640: <http://trac.webkit.org/changeset/142640>
All reviewed patches have been landed. Closing bug.