PHP 7 安装 Laravel 5.4 报错

在安装psysh扩展式提示：

Skipped installation of bin bin/psysh for package psy/psysh: file not found in packag
结束后运行：php artisan -V，会提示：

PHP Warning:  require(X:\wwwroot\blog\vendor\composer/../psy/psysh/src/Psy/functions.php): failed to open stream: No such file or directory in E:\wwwroot\blog\vendor\composer\autoload_real.php on line 66
PHP Fatal error:  require(): Failed opening required 'X:\wwwroot\blog\vendor\composer/../psy/psysh/src/Psy/functions.php' (include_path='.;C:\php\pear') in X:\wwwroot\blog\vendor\composer\autoload_real.php on line 66