Creating slurs across voices

In some situations it is necessary to create slurs between notes from different voices. The solution is to add invisible notes to one of the voices, using \hideNotes.

This example is measure 235 of the Ciaconna from Bach's 2nd Partita for solo violin, BWV 1004.

\version "2.24"

\relative c' {
  <<
    {
      d16( a') s a s a[ s a] s a[ s a]
    }
    \\
    {
      \slurUp
      bes,16[ s e](
      \hideNotes a)
      \unHideNotes f[(
      \hideNotes a)
      \unHideNotes fis](
      \hideNotes a)
      \unHideNotes g[(
      \hideNotes a)
      \unHideNotes gis](
      \hideNotes a)
    }
  >>
}