src/Model/User.php:124:42: MoreSpecificReturnType: The declared return type 'non-empty-string' for Sonata\UserBundle\Model\User::getUserIdentifier is more specific than the inferred return type 'string' (see https://psalm.dev/070)

src/Model/User.php:126:16: LessSpecificReturnStatement: The type 'string' is more general than the declared return type 'non-empty-string' for Sonata\UserBundle\Model\User::getUserIdentifier (see https://psalm.dev/129)

Process completed with exit code 2.

Method Sonata\UserBundle\Model\User::getUserIdentifier() should return non-empty-string but returns string.