The scary part for me is uncommenting it, because the code has been removed from normal QA and testing (automatic or manual) and you don't know what evils you are unleashing upon the world.
That's because you're not using Haskell. :) Herein lies the crux of my point. Haskell's purity and strong static types allow you to make lots of very strong assertions about what kind of evils you might be unleashing.
seems like this post should have been titled "What JavaScript(or its replacement) could learn from Haskel"