angular/angular.js — pull request #8747 by smilli (2014-08-23 18:12:38+00:00)
Title: refactor(ngRepeat): improve errors for duplicate items

-Log the value that had the duplicate key, as well as the key
The error that is thrown when items have duplicate track by keys can be
confusing because only the duplicate key is logged. If the user didn't
provide that key themselves, they may not know what it is or what item
it corresponds to.