Do not overwrite variable with unknown value

[guilliamxavier]

Q	A
Branch?	main
Bug fix?	yes
New feature?	no
Deprecations?	no
Tickets	Fix #4162
License	MIT
Doc PR

PhpStorm was complaining on line 33:

Unused local variable 'choices'. The value of the variable is overwritten immediately.

Also if you think about it, in the case of e.g. @Assert\Choice(callback={"App\Entity\Foo", "getBats"}) (or @Assert\Choice(callback="App\Entity\Foo::getBats")), i.e.

• $constraint->callback === ['App\Entity\Foo', 'getBats'] (or $constraint->callback === 'App\Entity\Foo::getBats') (note: typo, intended getBars)
• $constraint->choices === null
• $constraint->multiple === false

we would end up with an incorrect "enum": ["App\\Entity\\Foo", "getBats"] (or "enum": "App\\Entity\\Foo::getBats")

[alanpoulain]

Nice spotting, thanks.