The Department of Foreign Affairs, on its website, has travel advisories for all countries in the world.
The Iranian travel advisory includes—this is my recollection, and it's been a while since I've looked at it—reference to the fact that Iran does not recognize dual citizenship and that a Canadian-Iranian citizen being arrested will not, in the eyes of the Iranian government, be considered a Canadian citizen. So that's on our travel website, which we advise all Canadians to review before they travel to other countries. I'll just double-check to make sure it's still there. I know it's been there in the past.