[Routing] adding typehint to some functions and parameters

[helyakin]

Q	A
Branch?	6.4
Bug fix?	no
New feature?	no
Deprecations?	no

So i was walking around the Routing component for diverse reasons, and I came across some not type hinted:

• Function
• Parameter

I've also taken the freedom to add the property accessibility into the constructor since we are using php81

I have absolutely no idea if this PR is welcome, as this might be something you would not want to add to this framework for now.

Feel free to share your thoughts and opinions about this PR, I'll gladly learn whatever you might say about it !

Thanks again for your time

[wouterj]

Hi!

Adding a return type is a backwards compatibility break for child classes overriding this method. In 6.4, all methods have either a PHP return type or an @return PHPdoc (#47551, #50821). This results in a deprecation notices when you override a method without adding the correct PHP return type. In 7.0, we've added all missing return types (#50852, #50846) - except from some that we want to extend for another 2 years to avoid a big burden on the community.

For the same reasons, we've also limited property types to private or internal properties, or properties on final or internal classes (see #41924 for a bit more context).

Finally, I'm not sure what our policy is with CPP. I'm not too fond of it, as it's merely syntax sugar and can cause edge-case BC breaks as well: #45721 (comment)

[nicolas-grekas]

Closing as explained by @wouterj, thanks for proposing.