直接用官方的命令 composer require --dev barryvdh/laravel-ide-helper ，报错如下：
Problem 1
- barryvdh/laravel-ide-helper 2.12.x-dev is an alias of barryvdh/laravel-ide-helper dev-master and thus requires it to be installed too.
- barryvdh/laravel-ide-helper[dev-master, v2.12.0, ..., v2.12.3] require illuminate/console ^8 || ^9 -> found illuminate/console[v8.0.0, ..., 8.x-dev, v9.0.0-beta.1, ..., 9.x-dev] but these were not loaded, likely because it conflicts with another require.
- Root composer.json requires barryvdh/laravel-ide-helper ^2.12 -> satisfiable by barryvdh/laravel-ide-helper[v2.12.0, ..., 2.12.x-dev (alias of dev-master)].
解决办法：
安装低版本的即可。
执行命令
composer require --dev barryvdh/laravel-ide-helper 2.8