AA_SynthesizeTouchForUnhandledMouseEvents doesn't work on macOS

This is a new issue with Qt 5.10.0, Touch events (in addition to Mouse events) correctly appeared with Qt 5.9.2.

To reproduce, in main.cpp, set

QCoreApplication::setAttribute(Qt::AA_SynthesizeTouchForUnhandledMouseEvents);

Create a TouchTest.cpp file with a class TouchTest that is derived from QQuickItem:

class TouchTest : public QQuickItem
{
    Q_OBJECT
protected:
    virtual bool childMouseEventFilter(QQuickItem* item, QEvent* event);
}

In the overridden function, log the event type:

bool TouchTest::childMouseEventFilter(QQuickItem*, QEvent* event)
{
    qDebug() << "Touch event type =" << event->type();
}

Create a test.qml file with a TouchTest component.

Build the application with Qt 5.10.0 (Qt Creator 4.5) on macOS 10.13.2, run it and make a swipe gesture with the mouse (click, move, release).

Result: One MouseButtonPress, several MouseMove and one MouseButtonRelease.

Expected: In addition to the mouse events, I would expect TouchBegin, TouchUpdate and TouchEnd events.

Note: Works fine when built with Qt 5.9.2 on macOS. Works fine when built with Qt 5.10.0 for iOS or Android.