implicit "." not working if ambiguous to library import

Discovered while fixing : QTCREATORBUG-19194

The property editor in Qt Quick Designer stays white with Qt 5.10.

I get
 

qt-creator/share/qtcreator/qmldesigner/propertyEditorQmlSources/QtQuick/ItemPane.qml:272:25: LayoutSection is not a type

Adding import "." to ItemPane, LayoutSection and AdvancedSection seems to fix the issue.
This is a regression from Qt 5.9.2.

The problem comes from having QtQuick as a path under the import path see attachment.