What is the test for making out a discrimination claim under section 15 of the Charter?

The case of Law v. Canada, 1999 CanLII 675 (SCC), [1999] 1 S.C.R. 497 sets out the inquiries a court must make to determine whether a discrimination claim under section 15 of the Charter has been made out: First, does the impugned law (a) draw a formal distinction between the claimant and others on the basis of one or more personal characteristics, or (b) fail to take into account the claimant’s already disadvantaged position with Canadian society resulting in substantively differential treatment between the claimant and others on the basis of one or more personal characteristics? If so, there is differential treatment for the purpose of s. 15(1). Second, was the claimant subject to differential treatment on the basis of one or more of the enumerated and analogous grounds? And third, does the differential treatment discriminate in a substantive sense, bringing into play the purpose of s. 15(1) of the Charter in remedying such ills as prejudice, stereotyping, and historical disadvantage? The second and third inquiries are concerned with whether the differential treatment constitutes discrimination in the substantive sense intended by s. 15(1).