void (int opcode) { if (opcode == ARETURN && instrTracker.canBeNull() && info.nullability.isNotNull()) { mv.visitInsn(DUP); Label skipLabel = new Label(); mv.visitJumpInsn(IFNONNULL, skipLabel); String descrPattern = info.nullability.getNullResultMessage(); String[] args = info.nullability.message != null ? EMPTY_STRING_ARRAY : new String[]{myMethodData.myClassName, name}; reportError(info.nullability.exceptionType, skipLabel, descrPattern, args); } mv.visitInsn(opcode); }