如何在PHP中将对象数组定义为参数？

I want to something like this:

function __construct (string $todo, array[Tag] $tags) {}

That array[Tag] caused me a problem with error along the line: Unexpected '['

The main idea is to have strict type checking for an array of an object with Tag class.

How can I achieve this? And is it necessary for PHP's best practice?

Short answer, you can't. There is some hacky solution if you really need it though.