It seems creating a ListModel in a separate file, makes it impossible to use the custom QML type definition in another file to e.g. access the count property of ListModel.

There are errors like when building the application:

error: Cannot assign to non-existent default property
    ListElement {
    ^~~~~~~~~~~

And

error: Binding on property of unknown type
        cost: "2.45"
        ^~~~

Attached example shows the issue.