[HttpFoundation] inconsistent argument annotation for method $request->query->get()

[angelbachev]

Symfony version(s) affected: 5.1.*

Description
In version 5.1.* the type of $query property in Request class was changed from ParameterBag to InputBag.
InputBag extends ParameterBag but modified method get() signature.
This make the following code (which works fine in 5.0.*) invalid
$languages = $request->query->get('languages', ['en']);
In the project I'm currently working on we use PHPStan which is part of our continuous integration process.
PHPStan throws a lot of warnings because of this inconsistency.

How to reproduce
Run a PHPStan on a file which call $request->query->get() with array as default argument.

Possible Solution
Change Request::query type back to ParameterBag

Additional context
In Symfony 5.0.*

In Symfony 5.1.*

PHPStan error:
Parameter #2 $default of method Symfony\Component\HttpFoundation\InputBag::get() expects string|null, array<int, string> given.

According to the official Symfony 5.1.* documentation the type of query is ParameterBag, not InputBag.
https://symfony.com/doc/current/components/http_foundation.html#accessing-request-data

[Tobion]

The phpstan warning is correct. You'll also get a deprecation, see

symfony/src/Symfony/Component/HttpFoundation/InputBag.php

Lines 32 to 34 in 890f8f0

	if (null !== $default && !is_scalar($default) && !(\is_object($default) && method_exists($default, '__toString'))) {
	trigger_deprecation('symfony/http-foundation', '5.1', 'Passing a non-string value as 2nd argument to "%s()" is deprecated, pass a string or null instead.', __METHOD__);
	}

This is intentional per #34363

The documentation problem can be reported and fixed in https://github.com/symfony/symfony-docs. Thanks