QStyleOptionProgressBar doesn't display anything (no bar nor text) on Macos High Sierra

// Set up a QStyleOptionProgressBar to precisely mimic the
 // environment of a progress bar.
 QStyleOptionProgressBar progressBarOption;
 progressBarOption.state = QStyle::State_Enabled;
 progressBarOption.direction = QApplication::layoutDirection();
 progressBarOption.rect = option.rect;
 progressBarOption.fontMetrics = QApplication::fontMetrics();
 progressBarOption.minimum = 0;
 progressBarOption.maximum = 100;
 progressBarOption.textAlignment = Qt::AlignCenter;
 progressBarOption.textVisible = true;