Does a trial court's failure to instruct the jury on the applicable theory of theft constitute reversible error?

Several cases have considered whether a trial court's failure to instruct on the applicable theory of theft constitutes reversible error. In People v. Beaver, for instance, the Third District held that it was reversible error to instruct the jury on theft by larceny where the evidence could only support a conviction of theft by false pretenses. (People v. Beaver, supra, 186 Cal.App.4th at p. 125.) The appellate court reasoned that "the instructions read to the jury did not include all the elements necessary for a charge of theft by false pretenses," and "[t]hus, even if there was evidence in the record to support these elements, the jury was never called upon to determine if they had been established beyond a reasonable doubt." (Ibid.; see also People v. Curtin (1994) 22 Cal.App.4th 528, 531 [defendant's conviction of theft by trick could not be upheld on ground that evidence established his guilt of theft by false pretenses on which the jury was not instructed].)