[Validator] Add constraint on unique elements collection(Assert\Unique) #26535
Description
| Q | A |
|---|---|
| Bug report? | no |
| Feature request? | yes |
| BC Break report? | no |
| RFC? | no |
| Symfony version | 4.1 |
What about add constraint on unique elements collection?
I think it will be named as Assert\UniqueCollection.
It is partly linked with #9888
What do you think? I'd be happy to send a PR after it's discussed.