From Wikipedia:
A Reference Question to the Supreme Court of Canada
In Canadian law, a Reference Question is a submission by the federal or a provincial government to the courts asking for an advisory opinion on a major legal issue. Typically the question concerns the constitutionality of legislation.
Reference Jurisdiction of the Supreme Court
When Parliament created the Supreme Court of Canada in 1875, it gave the federal Cabinet the power to refer questions to the Supreme Court for the Court’s opinion. That provision has been carried forward and is now found in the current Supreme Court Act.
Under that provision of the Supreme Court Act, the federal Cabinet may submit a question to the Supreme Court of Canada, by means of an Order-in-council. Once the questions have been submitted to the Court, the Court has complete control over the process to be followed. The reference is treated in the same way as an appeal. The Attorney General of Canada is entitled to appear before the Court and to make submissions. The Attorneys General of the provinces and territories are entitled to notice of a reference and may appear on it. Interested parties are able to apply for intervener status to make submissions during the hearing. Where necessary the Court may appoint an amicus curiae to submit a factum to support a particular view.
Once the parties have been determined, the Court sets out a timetable for the filing of written submissions, and for the date of the hearing. Parties to the reference file detailed written submissions on the legal issues raised by the reference, supplemented by factual records if necessary. After all written submissions have been filed, the Court holds an oral hearing on the reference questions. At the conclusion of the hearing, the Court typically reserves its decision. At a later date, the Court releases its opinion on the reference, in the form of a detailed written judgment. Individual judges of the Court are entitled to dissent from the majority opinion, in the same way as with judgments in appeals.
The opinion given by the Supreme Court is in the form of a judicial decision but is not legally binding; nevertheless, no government has ever ignored the opinion.