Laravel throw console warning

I'm starting use laravel for a project. I've installed it like it's suggested on the official documentation, hovever, if I type laravel new projectname after I navigate to the macOS sites folder, It will give this errors

host:~ z$ laravel new kcms
Crafting application...
PHP Fatal error:  Uncaught Error: Call to undefined method Symfony\Component\Process\Process::fromShellCommandline() in /Users/z/.composer/vendor/laravel/installer/src/NewCommand.php:84
Stack trace:
#0 /Users/z/.composer/vendor/symfony/console/Command/Command.php(255): Laravel\Installer\Console\NewCommand->execute(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#1 /Users/z/.composer/vendor/symfony/console/Application.php(886): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#2 /Users/z/.composer/vendor/symfony/console/Application.php(262): Symfony\Component\Console\Application->doRunCommand(Object(Laravel\Installer\Console\NewCommand), Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#3 /Users/z/.composer/vendor/symfony/console/Application.php(145): Symfony\Component\Console\Applicat in /Users/z/.composer/vendor/laravel/installer/src/NewCommand.php on line 84

Fatal error: Uncaught Error: Call to undefined method Symfony\Component\Process\Process::fromShellCommandline() in /Users/z/.composer/vendor/laravel/installer/src/NewCommand.php on line 84

Error: Call to undefined method Symfony\Component\Process\Process::fromShellCommandline() in /Users/z/.composer/vendor/laravel/installer/src/NewCommand.php on line 84

Call Stack:
    0.0002     394608   1. {main}() /Users/z/.composer/vendor/laravel/installer/bin/laravel:0
    0.0081    1414560   2. Symfony\Component\Console\Application->run() /Users/z/.composer/vendor/laravel/installer/bin/laravel:13
    0.0202    1807648   3. Symfony\Component\Console\Application->doRun() /Users/z/.composer/vendor/symfony/console/Application.php:145
    0.0203    1807648   4. Symfony\Component\Console\Application->doRunCommand() /Users/z/.composer/vendor/symfony/console/Application.php:262
    0.0204    1807648   5. Laravel\Installer\Console\NewCommand->run() /Users/z/.composer/vendor/symfony/console/Application.php:886
    0.0209    1812424   6. Laravel\Installer\Console\NewCommand->execute() /Users/z/.composer/vendor/symfony/console/Command/Command.php:255

what's wrong?

via Chebli Mohamed