(let ((this-fret (calc-fret (ly:event-property note 'pitch)
string
tuning)))
+ (if (< this-fret 0)
+ (ly:warning (_ "Negative fret for pitch ~a on string ~a")
+ (note-pitch note) string))
(set! string-fret-fingering-tuples
(cons (list string
this-fret