As previously discussed in pull/31070 and issues/30486, this would be useful because it is often desirable to apply styles to fields that are both `ng-invalid` and `ng-pristine` after the first attempt at form submission, but Angular does not provide any simple way to do this (although evidently Angularjs did). This will now be possible with a descendant selector such as `.ng-submitted .ng-invalid`.
In this implementation, the directive that sets control status classes on forms and formGroups has its set of statuses widened to include `ng-submitted`. Then, in the event that `is('submitted')` is invoked, the `submitted` property of the control container is returned iff it exists. This is preferred over checking whether the container is a `Form` or `FormGroup` directly to avoid reflecting on those classes.
Closes#30486.
PR Close#42132.
This reverts commit 00b1444d12, undoing the rollback of this change.
PR Close#42132
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