Function delete_measures 

pub fn delete_measures(
    changes: &[Change],
    midi: &Stream,
    omr: &mut Stream,
) -> Result<()>

Takes out of the reading each measure holding a note changed from the performance’s: music21’s DeleteFixer, which “does really weird things still”.

Only a measure standing in the reading itself is taken out, as music21’s remove finds nothing deeper, so the measures of a score’s parts stay where they are.

Errors

A changed note in no measure, which music21 asks to remove nothing, or a change with no references.