Exception message: `There are no registered paths for namespace "__main__".`

Stack trace:
```
#0 /vagrant/symfony/vendor/twig/twig/lib/Twig/Loader/Filesystem.php(138): Twig_Loader_Filesystem->findTemplate('/tmp/sf-501ERx')
#1 /vagrant/symfony/vendor/twig/twig/lib/Twig/Environment.php(265): Twig_Loader_Filesystem->getCacheKey('/tmp/sf-501ERx')
#2 /vagrant/symfony/vendor/twig/twig/lib/Twig/Node/Module.php(127): Twig_Environment->getTemplateClass('/tmp/sf-501ERx', NULL)
#3 /vagrant/symfony/vendor/twig/twig/lib/Twig/Node/Module.php(51): Twig_Node_Module->compileClassHeader(Object(Twig_Compiler))
#4 /vagrant/symfony/vendor/twig/twig/lib/Twig/Node/Module.php(38): Twig_Node_Module->compileTemplate(Object(Twig_Compiler))
#5 /vagrant/symfony/vendor/twig/twig/lib/Twig/Compiler.php(86): Twig_Node_Module->compile(Object(Twig_Compiler))
#6 /vagrant/symfony/vendor/twig/twig/lib/Twig/Environment.php(543): Twig_Compiler->compile(Object(Twig_Node_Module))
#7 /vagrant/symfony/src/Symfony/Bridge/Twig/Command/LintCommand.php(136): Twig_Environment->compile(Object(Twig_Node_Module))
#8 /vagrant/symfony/src/Symfony/Bridge/Twig/Command/LintCommand.php(110): Symfony\Bridge\Twig\Command\LintCommand->validate(Object(Twig_Environment), '{{ foo }}', '/tmp/sf-501ERx')
#9 /vagrant/symfony/src/Symfony/Component/Console/Command/Command.php(252): Symfony\Bridge\Twig\Command\LintCommand->execute(Object(Symfony\Component\Console\Input\ArrayInput), Object(Symfony\Component\Console\Output\StreamOutput))
#10 /vagrant/symfony/src/Symfony/Component/Console/Tester/CommandTester.php(80): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArrayInput), Object(Symfony\Component\Console\Output\StreamOutput))
#11 /vagrant/symfony/src/Symfony/Bridge/Twig/Tests/Command/LintCommandTest.php(31): Symfony\Component\Console\Tester\CommandTester->execute(Array, Array)
#12 [internal function]: Symfony\Bridge\Twig\Tests\Command\LintCommandTest->testLintCorrectFile()
[...]
```