Question: My probationary period passed three days ago, I have not been told if I passed it, and I have my evaluation early next week. Should I assume that I have passed probation?

Answer: 
Check your contract. As a fellow Canadian, usually when I've seen probation contracts, the probation period is set by a specified number of days, not by an evaluation procedure. If that's what your contract looks like, then congratulations, you passed!

I have never had a formal meeting in any job to discuss passing probation; I have only had such a meeting when I failed it. If you are confused, you should ask your manager, but your manager will probably think you're being silly (not in a bad way, just in a "isn't it obvious?" way).
It depends where you are and the applicable laws, as well as what may (or not) be stated in your employment contract. In some places, you will likely need some confirmation that your probation period has been completed, in others it is the law that after a set number of days your probation has been completed by default.

In the latter case, you would now be a permanent employee and the termination process can become quite different. If the company wanted to let you go but missed the deadline, too bad for them, they need to comply with the laws that apply to an employee who is not on probation. This doesn't mean that they can't make your work life difficult, but the legal situation changes. In most cases, it is clear long before the end of a probation period whether a person is a good fit to the position/company. 

Sometimes companies try to exploit the probationary period as a short-term employment position by terminating on, or just before, the last day, because the requirements and remuneration are different (more favourable to the company) than employing a contractor.

In the former case, it would be usual to have the meeting/conversation some days prior to the end of the probation period, otherwise it is possibly *"within some reasonable period of time"*, and then your best option is probably to say something like, \*"hey boss, my probation was up last week," either before or at the evaluation meeting.