If I have a component Example.ui.qml file that references a bad alias like follows:

Item { 
    property alias test: badTest 
    Rectangle { 
        id: test 
        anchors.fill: parent 
    } 
}

The Designer text editor doesn't indicate an error for badTest. If you open the code-behind file Example.qml, the design view shows a blank placeholder Item and the Navigator shows a caution icon next to the root element with this tooltip message:

Component with path [...] could not be created. Change the setting "Use QML emulation layer that is built with the selected Qt" might solve the issue.

Ideally, the following would happen:

• The text editor when used on Example.ui.qml would show the alias value as an error
• The designer when used on Example.qml would properly report an error about the alias

Here's debug output from the puppet emulation layer process in the first case:

Editor Puppet: "<Unknown File>:1: ReferenceError: badTest is not defined"

Here's debug output from the puppet emulation layer process in the second case:

Editor Puppet: "QQmlComponent: Component is not ready"
Editor Puppet: "\"/Users/dhess/Desktop/Qt Designer Crash/Crash/ExampleUI.ui.qml\""
Editor Puppet: "file:///Users/dhess/Desktop/Qt Designer Crash/Crash/ExampleUI.ui.qml:4:26: Invalid alias reference. Unable to find id \"badTest\" "
Editor Puppet: "         property alias test: badTest "
Editor Puppet: "                              ^" 

The example project referenced is attached to this issue.