barNumberCheck with repeats

[Robert Schmaus]

Dear Ponderers,

I've got the following question about a problem involving bar number 
checks and repeats. When I'm engraving a bigger project, I find it 
useful to employ bar number checks. I also find it very useful to use 
the technique of having seperate layout and midi score blocks, the 
latter with \unfoldRepeats, as described here:
http://lilypond.org/doc/v2.18/Documentation/notation/repeats-in-midi

However, if there are "repeat volta" sections present in the score, all 
bar number checks seem to be off in the midi generation. Consider the 
following snippet:

%%%%%%%%%%%%%%%%%%%
\version "2.19.35"

music = \relative c'' {

  \barNumberCheck #1
  c c c c

  \barNumberCheck #2
  \repeat volta 2 { d d d d }

  \barNumberCheck #3
  e e e e
}

\score {
  \unfoldRepeats
  \music
  \layout{}
}
%%%%%%%%%%%%%%%%%%%

If unfoldRepeat is used in the score block, the bar number check 
(sensibly) expects the last bar to be bar # 4, not 3.

As workaround, I could leave out \unfoldRepeats while creating the score 
and just use it for the final engraving. But there might be some trick 
to have the bar number checks supressed in a score block - does anyone know?

Thanks!
Best,
Robert