As we were working on this issue https://clojure.atlassian.net/browse/CLJ-2698, we were looking in the world for cases of defprotocol methods with ^double and ^long return type hints (which are not valid - protocol methods always return Object) and found PRowCount and PColumnCount in tech.v3.dataset.protocols - I would recommend removing those type hints as they are not valid. But FYI, I am not expecting any change in behavior in Clojure in 1.12.
As we were working on this issue https://clojure.atlassian.net/browse/CLJ-2698, we were looking in the world for cases of defprotocol methods with ^double and ^long return type hints (which are not valid - protocol methods always return Object) and found PRowCount and PColumnCount in tech.v3.dataset.protocols - I would recommend removing those type hints as they are not valid. But FYI, I am not expecting any change in behavior in Clojure in 1.12.