Passing TextFile service variable to JavascriptCommand in qbs crashes Qt Creator

Essentially, if you do stuff like this while doing a QBS build, qt creator will crash:

var file = new TextFile(someFile, TextFile.ReadOnly)
var cmd = new JavaScriptCommand();
cmd.file = file;

The console that launched creator has these lines pre crash:
QVariant::load: unable to load type 39.
QVariant::save: unable to save type 'QObject*' (type id: 39).