don't know why this has so many downvotes.
The code in question was only subject to very high level smoke tests that looked like they were basically cherry picked best case scenarios intended to pass.
A unit test would have picked this up before it even got to production.
If typos are even a significant problem in your code then the solution is to type more slowly, have your IDE flag unknown symbols, use autocomplete, etc. As a solution to this problem, strong typing is both disproportionate and inadequate.