+
+
+@node Error message unexpected new
+@unnumberedsubsec Error message unexpected @code{@bs{}new}
+
+A @code{\score} block must contain a @emph{single} music expression.
+If instead it contains several @code{\new Staff},
+@code{\new StaffGroup} or similar contexts introduced with @code{\new}
+without them being enclosed in either curly brackets,
+@code{@{ @dots{} @}}, or double angle brackets, @code{<< @dots{} >>},
+like this:
+
+@example
+\score @{
+ % Invalid! Generates error: syntax error, unexpected \new
+ \new Staff @{ @dots{} @}
+ \new Staff @{ @dots{} @}
+@}
+@end example
+
+@noindent
+the error message will be produced.
+
+To avoid the error, enclose all the @code{\new} statements in
+curly or double angle brackets.
+
+Using curly brackets will introduce the @code{\new} statements
+sequentially:
+
+@lilypond[quote,verbatim]
+\score {
+ {
+ \new Staff { a' a' a' a' }
+ \new Staff { g' g' g' g' }
+ }
+}
+@end lilypond
+
+@noindent
+but more likely you should be using double angle brackets so the new
+staves are introduced in parallel, i.e. simultaneously:
+
+@lilypond[quote,verbatim]
+\score {
+ <<
+ \new Staff { a' a' a' a' }
+ \new Staff { g' g' g' g' }
+ >>
+}
+@end lilypond
+
+@node Warning this voice needs a voiceXx or shiftXx setting
+@unnumberedsubsec Warning this voice needs a @code{@bs{}voiceXx} or @code{@bs{}shiftXx} setting
+
+If notes from two different voices with stems in the same direction
+occur at the same musical moment, but the voices have no
+voice-specific shifts specified, the warning message
+@samp{warning: this voice needs a \voiceXx or \shiftXx setting} will appear
+when compiling the LilyPond file. This warning will appear even when
+the notes have no visible stems, e.g. whole notes, if the stems for
+shorter notes at the same pitch would be in the same direction.
+
+Remember that the stem direction depends on the position of the
+note on the staff unless the stem direction is specified, for example
+by using @code{\voiceOne}, etc. In this case the warning will appear
+only when the stems happen to be in the same direction, i.e. when the
+notes are in the same half of the staff.
+
+By placing the notes in voices with stem directions and shifts
+specified, for example by using @code{\voiceOne}, etc., these warnings
+may be avoided.
+
+Notes in higher numbered voices, @code{\voiceThree} etc., are
+automatically shifted to avoid clashing note columns. This causes a
+visible shift for notes with stems, but whole notes are not visibly
+shifted unless an actual clash of the note heads occurs, or when the
+voices cross over from their natural order (when @code{\voiceThree}
+is higher than @code{\voiceOne}, etc.)
+
+@seealso
+@rlearning{Explicitly instantiating voices},
+@rlearning{Real music example},
+@ruser{Single-staff polyphony},
+@ruser{Collision resolution}.