Symfony version(s) affected: 4.3.4

Description
When binding arguments with a type, types should be valid if no typehint is used for the constructor argument.

How to reproduce

class PhoneNumberNormalizer implements NormalizerInterface, DenormalizerInterface
{
    public function __construct(PhoneNumberUtil $phoneNumberUtil, $region = PhoneNumberUtil::UNKNOWN_REGION)
    {
        // ...
    }
}

register it like:

   App\PhoneNumberNormalizer:
        bind:
            string $region: 'DE'
        tags:
            - { name: serializer.normalizer, priority: 100 }

will raise an error:

  A binding is configured for an argument of type "string" named "$region" for service "Misd
  App\PhoneNumberNormalizer" in file "/Users/oskar.stark/dev/backend/config/services.yaml", but no corresponding argument has been found. It may be unused and should be removed, or it may have a typo.

Workaround

   App\PhoneNumberNormalizer:
        bind:
-            string $region: 'DE'
+            $region: 'DE'
        tags:
            - { name: serializer.normalizer, priority: 100 }

Removing the string typehint on the binding fixes the problem.
For me using string here, if the argument itself has no typehint in the constructor is fine.

WDYT?