Make "Don't know how to parenthesize spanners." warning, not programming error

Also add location information.

diff --git a/lily/parenthesis-engraver.cc b/lily/parenthesis-engraver.cc
index d021be9be45529bf262b87970abaa0c5aa54f465..abd1d07cc405cd1992ee9a9adbb363939256747f 100644 (file)
--- a/lily/parenthesis-engraver.cc
+++ b/lily/parenthesis-engraver.cc
@@ -67,7 +67,7 @@ Parenthesis_engraver::acknowledge_grob (Grob_info info)
             }
           else
             {
-              programming_error ("Don't know how to parenthesize spanners.");
+              info.grob ()->warning ("Don't know how to parenthesize spanners.");
             }
         }
     }