angular: Forms should throw error if two or more NgModels appear in form with the same name

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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]