What is the legal test for a failure to instruct the jury on an element of a sentence enhancement?

As errors go, the court's ruling can be likened to a failure to instruct on an element of an offense or an element of a sentence enhancement or to a failure to have the jury determine aggravating sentencing factors. In those situations, the appropriate trier of fact has not been expressly required to make a factual finding that is necessary for the imposition of a particular punishment. In those situations, the error is subject to Chapman standard. (People v. Flood (1998) 18 Cal.4th 470, 475, 503 [failure to instruct on element]; People v. Sengpadychith (2001) 26 Cal.4th 316, 326 [failure to instruct on element of sentencing enhancement]; People v. Sandoval (2007) 41 Cal.4th 825, 838 [failure to submit aggravating sentencing factor to jury].)

Under that standard, the failure to instruct on an element of an offense or enhancement may be deemed harmless where "the factual question posed by the omitted instruction necessarily was resolved adversely to the defendant under other, properly given instructions." (People v. Flood, supra, 18 Cal.4th at p. 485.) Similarly, the failure to submit an aggravating sentencing factor to the jury may be deemed harmless if "the question of the existence of an aggravating circumstance or circumstances had been submitted to the jury, the jury's verdict would have authorized the upper term sentence." (People v. Sandoval, supra, 41 Cal.4th at p. 838.) Stated differently, the error is harmless where "a reviewing court concludes, beyond a reasonable doubt, that the jury, applying the beyond-a-reasonable-doubt standard, unquestionably would have found true at least a single aggravating circumstance had it been submitted to the jury...." (Id. at p. 839.)