sstephenson/prototype — comment on commit 460be4691af9e4e92908c9ac707597bad69be57c
File: src/prototype/lang/array.js line 517
By dieseltravis:

The only other weird case that I've found is if you pass in an array of a single item: http://jsbin.com/ToUInt32/5 But I don't see that being an issue.