stepper: add ability to reset a step's form validation when moving to another step

[daniele-zurico]

Bug, feature request, or proposal:

proposal/bug

What is the expected behavior?

Make the ability to control the content of the form to the developer and put the next and previous button static.

What is the current behavior?

a form Control is required. And the prev and next button are built with directives.
Why the step should require a form inside and I'm not free to put whatever I want inside?

Example:
https://plnkr.co/edit/7QCrrhAhPFi4APLazxH6?p=preview

1. Arrive to the third step (it require validation) go back, the form is not reset, it still show the error. (I call form.reset())

2. You forced to say linear=false

[josephperrott]

I am not sure I am quite understanding the issue you are seeing, can you explain a bit more about what you are expecting to see?

A form control is not required for usage of the stepper as shown in this plunker.

[daniele-zurico]

From mi plunker arrive to the third step. Click on the input (to raise the validation error) go back on the second step and then go to the third again.
You’ll see that the input has still the validation active (is red).

[daniele-zurico]

Any news or workaround on that?

[Splaktar]

I tried to understand what is being requested here, but it's not clear to me.

You want to clear a step's form validation state when using the back button?