In D229 we have the comment by @valerio.bozzolan :

In general I personally suggest to "throw in case of problems" instead of "return null in case of problems".

I'm aware of the consequences so feel free to ignore me lol

We should decide if it's better to return some passaggi if others fail to parse (which is unlikely), or it's just correct to throw a ParserError and skip the passaggi source