Ted Cruz was never a Canadian citizen, although he was born there to permanent US resident parents.
To become a Canadian citizen, his US citizen mother would have had to submit an application before Ted reached the age of 22; she did not do so.
He formally renounced his Canadian citizenship while running for the Presidency.
https://www.scribd.com/doc/229048360/Ted-Cruz-Canadian-Citizenship-Renunciation-Letter
Ted Cruz’s father was not a U.S. Citizen when Ted was born in Canada. Ted’s father was a Cuban Citizen: http://www.kerchner.com/protectourliberty/petition-tedcruznotnaturalborncitizen.pdf