mat-select shows placeholder instead of option when ngModel is undefined (REGRESSION)

[thw0rted]

Bug, feature request, or proposal:

Bug

What is the expected behavior?

mat-select should show the mat-option with no [value] when its ngModel is undefined.

What is the current behavior?

It shows its placeholder value instead.

What are the steps to reproduce?

Open the examples tab in the docs, change "Select with 2-way value binding" to "None". Resulting control is blank, should show "None".

Which versions of Angular, Material, OS, TypeScript, browsers are affected?

Material 5.0.2, 5.1.0 (at least)

Is there anything else we should know?

This definitely used to work, though I'm not sure how long ago it broke.

[crisbeto]

This is the expected behavior. Closing as a duplicate of #7758.

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}