I did not see the link to the intersection issue. Is it this? (http://dev.clojure.org/jira/browse/CLJ-1682?page=com.atlassian.jira.plugin.system.issuetabpanels:

I did not see the link to the intersection issue. Is it this? (http://dev.clojure.org/jira/browse/CLJ-1682?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel#issue-tabs http://dev.clojure.org/jira/browse/CLJ-1682?page=com.atlassi...) So "nonsense values" returned by `intersection` means it returns a seq when you pass in a seq? So `(:key_1)` rather than `#{:key_1}`?