discussed Cited as authority (rule) United States v. Carl S. Begay They were held not to mandate reversal in all instances, but the test that must be followed is one of heightened scrutiny: “Before a federal constitutional error can be held harmless, the court must be able to declare a belief that it was harmless beyond a reasonable doubt.” Id. at 24 , 87 S.Ct. at 828; Yates v. Parker, — U.S. -, -, 111 S.Ct. 1884, 1892-93 , 114 L.Ed.2d 432 (1991) (constitutionally erroneous jury instructions require harmless-error analysis under Chapman)-, Arizona v. Fulminante, 499 U.S. -, -, 111 S.Ct. 1246, 1264 , 113 L.Ed.2d 302 (1991) (admission of coerced confessio…