[luatex] \hrule misplacement

[christian]

Hi,

when compiling the following mwe with luatex [Version 
beta-0.70.2-2012052410 (TeX Live 2012)], the "foo" word is not in the 
baseline in the pdf output:

%%%%%%%%%%%%%%%%%%
Begining
\vbox{%
     \hbox{myfoobar}%
     \hrule width0pt depth0pt height5pt
     \hbox{foo}%
}
the end.
\bye
%%%%%%%%%%%%%%%%%%

It seems that the \hrule is placed at the bottom of the \vbox instead 
between the \hbox's.
Sorry for the noise if it is a known bug.

Christian