I’d probably have just stuck with strings as well.

And this argument works as long as nothing wrong happens. Well, something wrong happened ;)

Smashing strings together is how this bug happened.

Constructing URLs reliably should have been the obvious first takeaway, was my point, instead of pretending the issue is not there. If Url::join() is somehow too confusing for some, then there are other ways to do it with simpler API, no problem.