Is there a type hint for an array of objects of a specific class in PHP 8.3?

If you're using PhpStorm, PHPStan or Psalm, types can be defined in PHPDocs and these tools will do the type checking, among many other things.

/** @var Task[] $tasks */
private array $tasks;

With new PHP features you can ensure that your array is always of type Task using variadic:

class MyClass
{
    /**
     * @var Task[] $tasks
     */
    private array $tasks = [];

    public function setTasks(Task ...$tasks) {
        $this->tasks = $tasks;
    }
}

$myClass = new MyClass();
$myClass->setTasks(...$tasksArray);
// or
$myClass->setTasks(new Task(), new Task(), new Task());

Since setTasks will always accept only Task as any parameter, there is no way to set anything else. We use this approach to bypass missing arrayof feature.

You can even incorporate magic methods to work with.

While there is not a type hint available for such compound types, there is a workaround that enforces type. Create a subclass from ArrayObject and validate all values added to the ArrayObject. Then you can type hint your new subclass.

<?php

class Collection extends ArrayObject
{
    public function __construct(array $items = [])
    {
        foreach ($items as $item) {
            $this->validate($item)
        }
    }

    public function append($value): void
    {
        $this->validate($value);
        parent::append($value);
    }

    public function offsetSet($key, $value): void
    {
        $this->validate($value);
        parent::offsetSet($key, $value);
    }

    protected function validate($value): void
    {
        if (!$value instanceof Task) {
            throw new InvalidArgumentException(
                'Not an instance of Task'
            );
        }
    }
}

Now you can return objects with a type hint of Collection and it will behave exactly as an array of Task objects.