Not inferring for implements?

We have a refactoring (shipping in 1.10.520) which assumes we are inferring on implements?

https://github.com/clojure/clojurescript/commit/7bd33f5e21501dbf41d7915e2c383c0138277895

The expected optimization in that commit is actually not in play. If you look at the generated source for count for example, you don't see coll.cljs$core$ICounted$_count$arity$1.

I think this is a simple mixup / oversight that we didn't see with respect to implements? and instance?.