In what circumstances will testimony that a defendant fits the profile of a typical heroin dealer be inadmissible in a trial for possession of the drug?

Similarly, in People v. Castaneda (1997) 55 Cal.App.4th 1067, 64 Cal.Rptr.2d 395, testimony that the defendant "perfectly fit" the "profile of the typical heroin dealer in Northern San Diego County" was inadmissible in a trial for possession of heroin. The court held that "every defendant has the right to be tried based on evidence tying him to the specific crime charged, and not on general facts accumulated by law enforcement regarding a particular criminal profile." (Id. at p. 1072, 64 Cal. Rptr.2d 395.)