Are there any exceptions to a jury finding a defendant guilty of murder under section 1157?

Nor is the conclusion that section 1157 contains no exceptions novel. In People v. McDonald (1984) 37 Cal.3d 351, 208 Cal. Rptr. 236, 690 P.2d 709, the prosecution asserted that a verdict form finding the defendant guilty of murder without specifying the degree could nonetheless be construed as a first degree murder conviction under section 1157. It argued, as does the prosecution here, that the jury had impliedly found the defendant guilty of first degree murder, given that the jury was instructed only on first degree murder and given that it found true a robbery-murder special circumstance.