Binding on input [type] is broken

[GuyShaanan]

I'm submitting a ...

[x] bug report => search github for a similar issue or PR before submitting

Current behavior
Try to bind the type attribute of input:

// in Class
inputType="number"

// in html
<input [type]="inputType" formControlName="integerB" />

Initially, the value is presented as number when doing form.value:

{"integerB": 5}

Now, try to change the input's value.

Its type has changed to string:

{"integerB": "5"}

while it seems the html attributes haven't changed:

// chrome dev console
<input formcontrolname="integerB" ng-reflect-name="integerB" ng-reflect-type="number" type="number" class="ng-valid ng-dirty ng-touched">

Expected behavior
If we are able to bind to [type], the input type should have stayed "number", so does the value.

Minimal reproduction of the problem with instructions
http://plnkr.co/edit/kp0xoDbZmJnD5orOTZUj?p=preview

What is the motivation / use case for changing the behavior?
I'm dynamiclly generating forms from given JSON, so binding to [type] can save a lot of copy-paste code.

Please tell us about your environment:
Not sure this is relevant as it is reproducible in plnkr.

Thanks.

Edit: same goes if binding [type] to inputType="checkbox".
Edit2: this is also broken in the Dynamic Forms demo if you change "email" type to number (for example)

[DzmitryShylovich]

Duplicate of #7329

[GuyShaanan]

Looks like a dup indeed, although my issue is not restricted to ngModel only but also for ReactiveForms.

The Dynamic Forms demo still demonstrates this behaviour (the ability to bind to [type]) and is misleading.

[DzmitryShylovich]

<input formControlName="integerB" [type]="'number'"/> 
<input formControlName="integerB" [attr.type]="'number'"/>

doesn't trigger creation of NumberValueAccessor https://plnkr.co/edit/u9RAULnbb4lGTR6JJhos?p=preview So it's blocked by #11716

[michael-letcher]

Is this being fixed any time soon? It's a real gapping hole in a "big" feature of angular.

Check #21418 for a workaround I use.

Would be nice too if the docs say you don't support reactive forms completely and that it's state is actually incomplete...