I do not think the treaty would affect your residency in the US for tax purposes. If you have not passed the substantial presence test for 2018, you would be considered a nonresident of the US for 2018 tax purposes and will need to file a US nonresident return.
TurboTax does not support nonresident returns.
However we have a partnership with Sprintax offering a
nonresident tax filing solution to our TurboTax customers.
Visit
the TurboTax/Sprintax site for more info or to get started.
https://turbotax.intuit.ca/tips/using-the-united-states-canada-income-tax-treaty-to-reduce-double-ta...
You will be considered a United States resident
for tax purposes if you meet the substantial presence test for the calendar
year. To meet this test, you must be physically present in the United States
(U.S.) on at least:
- 31 days during the current year, and
- 183 days during the
3-year period that includes the current year and the 2 years immediately
before that, counting:
- All the days you
were present in the current year, and
- 1/3 of the days you
were present in the first year before the current year, and
- 1/6 of the days you
were present in the second year before the current year.
