Issue 1770 in lilypond: \displayLilyMusic causes error with \oneVoice

[lilypond]

Status: Accepted
Owner: ----
Labels: Type-Defect Priority-Critical

New issue 1770 by address@hidden: \displayLilyMusic causes error  
with \oneVoice
http://code.google.com/p/lilypond/issues/detail?id=1770

Reported by Toine Schreurs,
This code:

\version "2.14.1"
\displayLilyMusic { \oneVoice c' }

reports:
GNU LilyPond 2.14.1
Processing `bug.ly'
Parsing...
ERROR: Wrong type (expecting pair): ()

\voiceOne and family work fine.

Version 2.12 also breaks:
Starting lilypond 2.12.3 [Untitled]...
Processing `/tmp/tmpPyaSbB/document.ly'
Parsing...
/usr/share/lilypond/2.12.3/scm/define-music-display-methods.scm:868:24: In  
procedure cdr in expression (cdr properties):
/usr/share/lilypond/2.12.3/scm/define-music-display-methods.scm:868:24:  
Wrong type (expecting pair): ()