jashkenas/coffee-script — pull request #2334 by michaelficarra (2012-05-16 05:17:32+00:00)
Title: fixes #2333: fix prohibition of duplicate object properties

I don't really like my solution very much, so I've opened a pull request to see if anyone wants to take a stab at refactoring. **+1** if you think it's fine the way it is, and I'll merge it.