What is the legal test for errors of law or mixed fact and law?

Errors of law or mixed fact and law leave more latitude to an appellate court. Regarding issues of law, the standard is correctness: Housen v. Nikolaisen, supra. Findings of mixed fact and law lie along a spectrum: if the error can be attributed to the application of an incorrect legal principle, then the standard is correctness; if the legal principle, however, cannot be extricated, and the appellate court is dealing with the application of a legal standard to a set of facts, it is a question of mixed fact and law, then the “question is subject to a standard of palpable and overriding error unless it is clear that the trial judge made some extricable error in principle with respect to the characterization of the standard or its application, in which case the error may amount to an error of law”: Housen, supra at para. 37.