<?php

​

declare(strict_types=1);

​

abstract class AbstractValue

{

    public function __get(string $name): mixed

    {

        return 123;

    }

    public function __set(string $name, mixed $value): void

    {

    }

}

​

/** @property int $foo */

final class FooValue extends AbstractValue

{

}

​

/** @template T of AbstractValue */

abstract class AbstractClass

{

    /** @var T */

    private AbstractValue $value;

​

    /** @param T $value */

    public function __construct(AbstractValue $value)

    {

        $this->value = $value;

    }

​

    /** @return T */

    protected function getValue(): AbstractValue

    {

        return $this->value;

    }

}

​

/** @extends AbstractClass<FooValue> */

final class Test extends AbstractClass

{

    public function __construct()

    {

        parent::__construct(new FooValue());

​

        // Works:

        echo $this->getValue()->foo;

​

        // Works:

        $v = $this->getValue();

        $v->foo = 1;

​

        // Fails with: Magic instance property FooValue::$foo is not defined

        $this->getValue()->foo = 1;

    }

}