What is the current state of the law in this jurisdiction?

As Seaton J.A. said in Regina v. Ewing at [W.W.R.] p. 239, that suggestion “has no application to a trial in this jurisdiction today”. By that I infer that Seaton J.A. was referring to the position accepted in Alberta as no doubt in British Columbia, but perhaps not in the United States, that the trial judge has a duty (even if there is defence counsel and he makes a mistake) “to see that only proper evidence was before the jury… [The judge] must take care that the prisoner is not convicted on any but legal evidence” (per Wills J. in Regina v. Gibson (1887), 18 Q.B.D. 537 at 543).