Using version mingw-w64-x86_64-qt5 version 5.11.2-2 i get the following error when using QtQuick:
error: file:///[...]/main_window.qml:17 Type ApplicationWindow unavailable
file:///[...]/msys64/mingw64/share/qt5/qml/QtQuick/Controls/ApplicationWindow.qml:240 ContentItem is not a type
Using version mingw-w64-x86_64-qt5 version 5.11.2-2 i get the following error when using QtQuick:
Reverting to 5.11.1-3 works as expected.