barchecks in lyrics mode confused by rests

[Mark Polesky]

Hey devs -

I just found a problem with an old doc-commit of mine
(0a8cfef, from May 7 2010).  I implicitly endorsed using
barchecks in the lyrics input (see LM 2.3.1 "Setting simple
songs").  Unfortunately, when the measure following a
barcheck starts with a rest, a "barcheck failed" warning
results, which is unsatisfactory:

* * * * * * * * * *

\version "2.13.59"

<<
  \relative c'' {
    \key g \major
    \time 6/8
    d4 b8 c4 a8 | r8 d b g4
  }
  \addlyrics {
    Girls and boys come | out to play,
  }
>>

* * * * * * * * * *

I suppose the options are:

1) remove the lyrics-barchecks from the docs, and mention
   (somewhere) that barchecks do not work in lyrics input.
2) make barchecks work in lyrics mode (i.e. with rests).

I prefer #2 -- I think it's a valuable feature to have.  But
as I've implied recently, I'm too busy at the moment to be
getting my hands dirty with LilyPond patches, though I do
have enough time to start discussions.  Should I file an
"Enhancement" issue on the tracker?

Thanks.
- Mark