[Validator] Add the type for ConstraintValidatorTestCase::createValidator

Author: stof

Tests/Extension/Validator/Constraints/FormValidatorTest.php

@@ -30,6 +30,7 @@
 use Symfony\Component\Validator\Constraints\NotBlank;
 use Symfony\Component\Validator\Constraints\NotNull;
 use Symfony\Component\Validator\Constraints\Valid;
+use Symfony\Component\Validator\ConstraintValidatorInterface;
 use Symfony\Component\Validator\Context\ExecutionContext;
 use Symfony\Component\Validator\Test\ConstraintValidatorTestCase;
 use Symfony\Component\Validator\Validation;
@@ -714,7 +715,7 @@ public function testCauseForNotAllowedExtraFieldsIsTheFormConstraint()
         $this->assertSame($constraint, $context->getViolations()->get(0)->getConstraint());
     }
 
-    protected function createValidator()
+    protected function createValidator(): ConstraintValidatorInterface
     {
         return new FormValidator();
     }