[jganetsk]

To the extent that a single case can prove anything, what is being done here in fact strengthens the case for dynamic typing, for it shows that a dynamic language can reap the benefits of static analysis too, WHEN it is beneficial.

You don't know that dynamic typing + static analysis is better than just static typing. Closure definitely does not catch everything. Hell, even just using the [] operator on a non-array object, Closure breaks down.