[ ] bug report => search github for a similar issue or PR before submitting
[x] feature request
[ ] support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question

Current behavior

Currently there is no error or warning if two form controls have the same name:

<input name="entireStateCoverage" type="checkbox" [(ngModel)]="item.entireStateCoverage">
<input name="entireStateCoverage" type="checkbox" [(ngModel)]="item.active">

Expected behavior

Forms should throw error if duplicate names are detected.

What is the motivation / use case for changing the behavior?

This leads to unpredictable results (value overwrites) which are difficult to find.

• Angular version: 2.4.3

• Browser: [all]

• Language: [all]