The issue is in bit mis-alignment, caused by http://trac.webkit.org/browser/trunk/WebCore/rendering/style/RenderStyle.h?rev=57292#L204. Setting _insideLink to any value clobbers fields around it in weird and unanderstandable ways.
will fix tomorrow, btw.
MSVC likes to make enum bitfields signed. _insideLink probably just needs to be bumped up to three bits. That or the type changed from EInsideLink to unsigned.
Created attachment 53962 [details]
Comment on attachment 53962 [details]
The correct fix is not to make the bitfield larger. Instead we type the bitfield "unsigned" and add a comment with the type:
unsigned _insideLink : 2; // EInsideLink
See the line above.
We might be able to change check-webkit-style to catch this.
Created attachment 53966 [details]
Thanks Darin! I should've thought of this. dhyatt did all the casting for me already.
Attachment 53966 [details] did not pass style-queue:
Failed to run "WebKitTools/Scripts/check-webkit-style" exit_code: 1
WebCore/rendering/style/RenderStyle.h:206: _insideLink is incorrectly named. Don't use underscores in your identifier names. [readability/naming] 
Total errors found: 1 in 2 files
If any of these errors are false positives, please file a bug against check-webkit-style.
Landed as http://trac.webkit.org/changeset/57994.
http://trac.webkit.org/changeset/57994 might have broken Qt Linux Release