I thought about this. I thought I wanted a different solution using virtual nodes but it'd need a lot of refactoring. And maybe it'd still be very hard.

For similar reasons I already added $scope->pushInFunctionCall() in the same Check class.

So feel free to pursue the same direction you started 😊

This pull request has been marked as ready for review.

I've looked at this and here are my thoughts: I don't like that FunctionCallParametersCheck::check() gains full reflection as another parameter. This isn't how I would design this. There are enough things already passed from reflection that this change really feels like it's bolted on to achieve a single goal.

Since the goal is to basically change $parameter from already passed $parametersAcceptor, I feel like we should modify $parametersAcceptor before it's passed to the check() method.

So the rules that call FunctionCallParametersCheck should modify ParametersAcceptor before it's passed there.

Alright, I see this is just an alternative to #3282. I will merge that instead. Thank you.