Marriage overrules common law designation.
I agree but where it MAY be relevant to some, and in context of immigration/IRCC in particular:
-if you were (are found to have been) common law before getting married, IRCC rules regarding the requirement to disclose a spouse (common law or married) when one becomes a PR will apply - and very much apply.
Or in other words, if you were common law - for clarity, ACCORDING TO IRCC UNDERSTANDING (i.e. 12 months cohabitation, not 'local law' abroad) - immigrated and became a PR without disclosing that common law relationship, then you can never sponsor that spouse. Getting married after the fact doesn't make that previous common law disappear.
[for clarity, avoidance of doubt, etc.]
For other contexts, well, 'it depends' and see a lawyer. I daresay that many jurisdictions / family courts may well treat a relationship involving lengthy cohabitation before marriage as continuation of a single 'marriage like' relationship IF that matters for the question at hand.
