When logged in on a vBulletin forum like the one at mania.com, select the Forum Tools menu and choose "Mark This Forum Read". Any unread threads should switch from bolded text (unread) to plain text (read). Under r51978, this works and the console says: XHR finished loading: "http://www.mania.com/aodvb/ajax.php?do=markread&f=30". Under r52039, nothing happens and the console says: XHR finished loading: "http://www.mania.com/aodvb/30". Notice a good portion of the correct link is missing on the failing result.
Confirmed with r52124 on PowerPC. Works fine on Intel.
<rdar://problem/7471495>
Reduction: alert('a' + 1) gives '1'.
Committed revision 52182.
*** Bug 32543 has been marked as a duplicate of this bug. ***
I'm not sure if this is completely fixed after all. I'm still seeing some issues that I can trace back to the same build number for when the problem starts. Check out this other bug to see if it's related to the same thing. https://bugs.webkit.org/show_bug.cgi?id=33383
(In reply to comment #6) Probably not the exact same problem, since this particular bug was a simple typo.
(In reply to comment #7) Sure, I wouldn't think it's the exact problem either, but I thought it might be related to the same initial changes that came with the build that has caused both issues to begin occurring. I haven't been able to reliably use a Webkit build since early December due to this and I'm concerned.