CRA indicates that the deemed U.S. income inclusion from an IRA on renouncing U.S. citizenship or relinquishing a green card also is recognized for ITA purposes

Where a U.S. long-term resident relinquishes her green card (or a U.S. citizen renounced citizenship) after having become a Canadian resident, there would be a deemed taxable distribution to her of the amount in her IRA for Code purposes – which by virtue of ss. 56(1)(a)(i)(C.1) and 56(12) would be deemed to be included in her income at that time for ITA purposes as well. This generally would accommodate a s. 126(1) foreign tax credit.

Subsequent (actual) withdrawals of the IRA funds generally would not be subject to further Canadian taxability.

Neal Armstrong. Summary of 29 January 2018 External T.I. 2017-0682301E5 under s. 56(1)(a)(i)(C.1) and s. 126(1).