metainfo file for Qt.labs.controls 1.0 doesn't work while in Qt Creator 3.5.0

I am using Qt Creator 3.5.0(Qt 5.5.0), and also tried latest master(0e8a0cac475b3127ce1fac95214c3f252124a461, Qt 5.6). OS X 10.10.

My latest qtbase/qtdeclarative/qtquickcontrols/qtquickcontrols2 5.6 branch build, qtqc2 with https://codereview.qt-project.org/126994 .

And then use "Qt Quick Controls Application" template, 5.5, with ui.qml.

Manually modified MainForm.ui.qml as:

import QtQuick 2.5
import Qt.labs.controls 1.0
import QtQuick.Layouts 1.2

Item {
    width: 640
    height: 480
}

And when I drag Qt.labs.controls Button to it, will get a warning "Invalid property name \"x\". (M16)". And I have something in log:

RewriterException: "Invalid property name \"x\". (M16)"
Content: "import QtQuick 2.5\nimport Qt.labs.controls 1.0\nimport QtQuick.Layouts 1.2\n\nItem {\n    width: 640\n    height: 480\n    \n    Button {\n        x: -159\n        y: -64\n    }\n}\n"
Error: "Invalid property name \"x\". (M16)"

Any hint to fix the issue?

Also tried "puppet" after Tim's suggestion, but still same.