+/*
+ Both filter_performers and filter_engravers used to use a direct dynamic_cast
+ on the unsmobbed translator to be filtered, i.e.,
+
+ if (dynamic_cast<Performer *> (unsmob_translator (scm_car (*tail))))
+
+ but this caused mysterious optimisation issues in several GUB builds. See
+ issue #818 for the background to this change.
+*/