Trying to get property on a non-object when parsing a list in short array syntax

[greg0ire]

Q	A
Bundle version	1.4.3
Symfony version	4.1.9
PHP version	7.1

Expected behavior

No crash

Actual behavior

In FormExtractor.php line 169:
                                                
  [ErrorException]                              
  Notice: Trying to get property of non-object  
                                                

Exception trace:
 () at /app/vendor/jms/translation-bundle/JMS/TranslationBundle/Translation/Extractor/File/FormExtractor.php:169
 JMS\TranslationBundle\Translation\Extractor\File\FormExtractor->getDomain() at /app/vendor/jms/translation-bundle/JMS/TranslationBundle/Translation/Extractor/File/FormExtractor.php:119
 JMS\TranslationBundle\Translation\Extractor\File\FormExtractor->enterNode() at /app/vendor/nikic/php-parser/lib/PhpParser/NodeTraverser.php:123
 PhpParser\NodeTraverser->traverseNode() at /app/vendor/nikic/php-parser/lib/PhpParser/NodeTraverser.php:146
 PhpParser\NodeTraverser->traverseNode() at /app/vendor/nikic/php-parser/lib/PhpParser/NodeTraverser.php:223
 PhpParser\NodeTraverser->traverseArray() at /app/vendor/nikic/php-parser/lib/PhpParser/NodeTraverser.php:114
 PhpParser\NodeTraverser->traverseNode() at /app/vendor/nikic/php-parser/lib/PhpParser/NodeTraverser.php:223
 PhpParser\NodeTraverser->traverseArray() at /app/vendor/nikic/php-parser/lib/PhpParser/NodeTraverser.php:114
 PhpParser\NodeTraverser->traverseNode() at /app/vendor/nikic/php-parser/lib/PhpParser/NodeTraverser.php:223
 PhpParser\NodeTraverser->traverseArray() at /app/vendor/nikic/php-parser/lib/PhpParser/NodeTraverser.php:114
 PhpParser\NodeTraverser->traverseNode() at /app/vendor/nikic/php-parser/lib/PhpParser/NodeTraverser.php:223
 PhpParser\NodeTraverser->traverseArray() at /app/vendor/nikic/php-parser/lib/PhpParser/NodeTraverser.php:91
 PhpParser\NodeTraverser->traverse() at /app/vendor/jms/translation-bundle/JMS/TranslationBundle/Translation/Extractor/File/FormExtractor.php:452
 JMS\TranslationBundle\Translation\Extractor\File\FormExtractor->visitPhpFile() at n/a:n/a
 call_user_func_array() at /app/vendor/jms/translation-bundle/JMS/TranslationBundle/Translation/Extractor/FileExtractor.php:235
 JMS\TranslationBundle\Translation\Extractor\FileExtractor->extract() at /app/vendor/jms/translation-bundle/JMS/TranslationBundle/Translation/ExtractorManager.php:137
 JMS\TranslationBundle\Translation\ExtractorManager->extract() at /app/vendor/jms/translation-bundle/JMS/TranslationBundle/Translation/Updater.php:253
 JMS\TranslationBundle\Translation\Updater->setConfig() at /app/vendor/jms/translation-bundle/JMS/TranslationBundle/Translation/Updater.php:143
 JMS\TranslationBundle\Translation\Updater->process() at /app/vendor/jms/translation-bundle/JMS/TranslationBundle/Command/ExtractTranslationCommand.php:131
 JMS\TranslationBundle\Command\ExtractTranslationCommand->execute() at /app/vendor/symfony/symfony/src/Symfony/Component/Console/Command/Command.php:255
 Symfony\Component\Console\Command\Command->run() at /app/src/ManoMano/TranslatorBundle/Command/SyncTranslationCommand.php:210
 ManoMano\TranslatorBundle\Command\SyncTranslationCommand->extractTranslations() at /app/src/ManoMano/TranslatorBundle/Command/SyncTranslationCommand.php:104
 ManoMano\TranslatorBundle\Command\SyncTranslationCommand->execute() at /app/vendor/symfony/symfony/src/Symfony/Component/Console/Command/Command.php:255
 Symfony\Component\Console\Command\Command->run() at /app/vendor/symfony/symfony/src/Symfony/Component/Console/Application.php:911
 Symfony\Component\Console\Application->doRunCommand() at /app/vendor/symfony/symfony/src/Symfony/Bundle/FrameworkBundle/Console/Application.php:89
 Symfony\Bundle\FrameworkBundle\Console\Application->doRunCommand() at /app/vendor/symfony/symfony/src/Symfony/Component/Console/Application.php:262
 Symfony\Component\Console\Application->doRun() at /app/vendor/symfony/symfony/src/Symfony/Bundle/FrameworkBundle/Console/Application.php:75
 Symfony\Bundle\FrameworkBundle\Console\Application->doRun() at /app/vendor/symfony/symfony/src/Symfony/Component/Console/Application.php:145
 Symfony\Component\Console\Application->run() at /app/bin/console:27

Steps to reproduce

Use a short list syntax, like this:
[,$b, $c] = [41, 42, 43]

The long list syntax (list(,$b, $c) = [41, 42, 43]) works.