Error/Assertion in projectresolver.cpp during qbs build

I fetched last qbs sources 2 days ago and started to play with it.

Well my very basic project gives me the following error:

D:\dev\git-repo\ant\src\Core>qbs build -f Core.qbs -k release profile:qt-5-2-1
No build graph exists yet for this configuration.
Resolving project for configuration qt-5-2-1-release
ERROR: language\projectresolver.cpp:976 ASSERT: f

I get basically the same result when switching to the Qt creator profil qtc_Desktop.

If I did something wrong in the .qbs files, which is possible, the error message does not help me to spot the mistake.

I have not attached source code, only .qbs.