Just take the first code segment as an example.
Are you wondering why the B object passed in completely disappeared when printed and turned into an A object?

Because although you $a(new B());了，但是匿名函数没接收啊，所以内部还是直接new A();

Execute this code and get a feel for it:

<?php
class A{}

class B{}

$a = function ($unknow = null){  //这里要接收的
    var_dump($unknow);
    return $unknow;
};

var_dump($a);

$b = $a(new B());

var_dump($b);

class A{}
class C{}
class B{
    public function run(){
     
        $b = function (){
           var_dump(func_get_args());  //接收参数
            return new A();
        };
        var_dump($b);   //第一次输出 $b 闭包
        var_dump($this); //第二次输出 $this。  就是class B
        return $b(new C());
    }
}
$b = new B();
var_dump($b->run());   //第三次输出  是$b这个匿名函数的返回值 class A

$b(new C()) Your anonymous function $b does not accept parameters