displayLilyMusic and scheme-engraver

[Jan-Peter Voigt]

Hi folks,

I just stumbled over a bug with \displayLilyMusic and scheme-engravers. 
The following fails in recent devel:

%%%

\version "2.19.55"

\displayLilyMusic \new Staff \with {
  \consists #(lambda (context)
               (make-engraver))
} \relative { bes'4 a c b }

%%%

ERROR: In procedure symbol->string:
ERROR: Wrong type argument in position 1 (expecting symbol): #<procedure 
#f (context)>

%%%

Until 2.19.53 or 54 this didn't crash, but the output was not a 
serialization of the context-mod (\with), so I assume, someone is 
working on it :-)

I will have a look into the internals after lunch.

Jan-Peter