I'm not sure if this is a PhpStorm issue or if it's an actual problem with the generated file, but I get a few errors when I open the _ide_helper.php file inside the editor. I know it's a generated file and that we're not supposed to edit it by hand. I sometimes open it just out of curiosity. Anyway, the errors appear to relate to the fact that there are multiple entries for a few class definitions. Here are two examples of such errors:

class Db extends \Illuminate\Support\Facades\DB {
    //...
}

class DB extends \Illuminate\Support\Facades\DB { 
    //...
}

class Url extends \Illuminate\Support\Facades\URL {
    //...
}

class URL extends \Illuminate\Support\Facades\URL {
    //...
}

It appears that both definitions of each one of these classes have identical members.