"While this build does get tested, it is still subject to bugs, as we want people to see what's new as soon as possible" and "Remember, Dev channel browsers and Canary builds may still crash frequently."
I know what the channel page says and what the dev channel is about, my issue is that multiple assignment is not a complex or advanced feature, which means either it's not tested or Chrome's devs don't even bother running any test suite before pushing changes.
What makes you think assignment is simple? V8 is a multi-stage, dynamically optimizing just-in-time compiler. That's complex and advanced, pretty much by definition.