tp6 composer install 报Your requirements could not be resolved to an installable set of packages。

1、tp6安装vendor包， 报Your requirements could not be resolved to an installable set of packages,如下图所示:

2、解决方法：

使用命令

　　composer install --ignore-platform-reqs
　　或者
　　composer update --ignore-platform-reqs

解决。