PHP:在类中或与类相同的文件中定义类别名

Can I define the class alias inside the class, or, at least, in the same file as class?

Currently, I can not import the References class as RF:

Class file:

class_alias('References', 'RF');

class References {

    // ...

}

Other file:

use App\Extenders\References;

class CreateOrdersTable extends Migration {

    public function up() {

        Schema::create(RF::tables // ...