Issue 3666: Format error message for argument errors more nicely

Actually, using display-lily-music here would be nicer, but it does not
cater for anything but music automatically like music->make-music
does.

diff --git a/scm/ly-syntax-constructors.scm b/scm/ly-syntax-constructors.scm
index b3d7f3f0f01cf942ef71f7db0caa19fd47db742f..5fe0bfbbefef410acd76fdf536c2b343695eaff9 100644 (file)
--- a/scm/ly-syntax-constructors.scm
+++ b/scm/ly-syntax-constructors.scm
@@ -73,7 +73,7 @@
    parser
    (format #f
            (_ "wrong type for argument ~a.  Expecting ~a, found ~s")
-           n (type-name pred) arg)
+           n (type-name pred) (music->make-music arg))
    location))
 
 (define-ly-syntax-simple (void-music)