Lazily instantiate the SubtypeSet, to prevent Throwable from being loaded too early.
Lazily instantiate the SubtypeSet, to prevent Throwable from being loaded too early.

liujed/polyglot-eclipse,blue-systems-group/project.maybe.polyglot,xcv58/polyglot,blue-systems-group/project.maybe.polyglot,liujed/polyglot-eclipse,blue-systems-group/project.maybe.polyglot,liujed/polyglot-eclipse,liujed/polyglot-eclipse,xcv58/polyglot,xcv58/polyglot,blue-systems-group/project.maybe.polyglot,xcv58/polyglot