Any major city in the world has crime and "back alley" problems. Canada is no exception. Toronto has plenty of crime. And there are lots of places you should not go.

Toronto PD puts together nice maps: https://data.torontopolice.on.ca/pages/maps

Ontario has one, too: https://www.ontarioca.gov/Police/CrimeMap

You can find this stuff by using your favorite search engine. You can usually find which neighborhoods and streets you would want to avoid.