<?php
 
class MyClass
{
    public $prop = "teste";
 
    public function test()
    {
        $class = new class($this->prop) {
 
            public function __construct($prop)
            {
                $this->prop = $prop;
            }
 
            public function run() 
            {
                $this->prop = "teste na classe anônima";
 
                echo $this->prop, PHP_EOL;
            }
 
        };
 
        $class->run();
    }
}
 
$obj = new MyClass();
$obj->test();
 
echo $obj->prop, PHP_EOL;

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