plugin.qmltype for the inherited QML types seem to be generated

The issue: Qt Creator tells the inherited properties of the custom controls as invalid.

The attached project(CoffeeMaker.zip) has custom controls defined in the module "CoffeeControls."

In the file LanguageRadioGroup.qml uses one of them; CoffeeRadioButton.

As you can see in the image above, the inherited properties from Qt Quick Templates, such as checked, text and onClicked are said to be invalid, although the program builds and runs without any issues.

As it turned out, when I checked the plugin.qmltypes(This file is attached to this Jira ticket) resides in the path which is shown when you hover over "import CoffeeControls 1.0" in the file, it only has newly defined properties in CoffeeRadioButton.qml, where it's supposed to have the inherited ones from Qt Quick Templates as well. 

The workaround is to import QtQuick.Templates 2.15 in LanguageRadioGroup.qml.