Issue 1681 in lilypond: \change Staff cannot be the first element inside a musical expression

[lilypond]

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

New issue 1681 by address@hidden: \change Staff cannot be the first  
element inside a musical expression
http://code.google.com/p/lilypond/issues/detail?id=1681

Reported by Eluze:

with this code the first note remains in the upper staff and 2 warnings are
output:

\version "2.13.62"
\new PianoStaff <<
  \new Staff = "up" {
    \relative c {
      \change Staff = "down" \repeat tremolo 4 {f16 { \change Staff = "up"
f' } }
  } }
  \new Staff = "down" {
    \relative c {
      \clef bass
          d,1 |
  } }
> > >>
http://old.nabble.com/file/p31746913/test.png

warning: Change_iterator::process (): Staff = `up':
test.ly:5:6: warning: cannot change `Staff' to `down': not changing to same
context type: Staff


this is healed by:

- explicitly declaring the voices
- inserting s1*0
- adding \key … (but not \clef or \time)
- using an \override of a grob attribute (e.g. \override NoteHead #'color =
#black)

cheers
Eluze

To amplify: \change Staff cannot be the first element of the innermost  
musical expression. Marked medium because of the simple workarounds.