diff --git a/libguile/guile-snarf.c b/libguile/guile-snarf.c
index c07472856..5feafd7c6 100644
--- a/libguile/guile-snarf.c
+++ b/libguile/guile-snarf.c
@@ -472,6 +472,9 @@ parse_args (char *keyword)
 	      else
 		add_char (&arg, c);
 	      break;
+
+	    default:
+	      abort ();
 	    }
 
 	  c = arglist_getc (keyword);