TimMc on IRC helped me find this line in the source: https://github.com/clojure/clojure/blob/1.3.x/src/jvm/clojure/lang/ARef.java#L29
If I change my validator to throw a RuntimeException, then I get the behavior I want. Thanks Tim! -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en