The Supreme Court of Canada appears to have completely disregarded standing in this case (
R. v. Nur,
2015 SCC 15).
A review of the opinion reveals that the Court was satisfied that the mandatory minimum punishment was appropriate for the particular accused before the Court, and indeed the Court declined to interfere with the sentences of the accused before the Court (para 119).
Since the sentence was appropriate for the accused before the Court, they were not in any way prejudiced by the mandatory minimum sentence and its alleged unconstitutionality. Therefore, they lacked standing to challenge the mandatory minimum and all three levels of Court really should not have considered the argument at all.
However, the Supreme Court has previously held that when it decides constitutional issues in a way that is technically unnecessary to the decision, those decisions are still binding. So the lack of regard for traditional standing principles doesn't vitiate the decision, although I don't understand why the Court didn't wait for a case where the mandatory minimum was actually objectionable.