If tools.reader 0.8.4 is included in a project's dependencies, then clojurescript fails to work in a browser, with the error that cljs.core.PersistentArrayMap is undefined. I have created a sample project demonstrating this at https://github.com/jamesnvc/cljs-toolreader-debugging.
I also apologize that I'm not sure if this is a problem in tools.reader or clojurescript. If there is a better place for me to report this issue, please let me know!
OS X 10.9.3, Java 1.8, Clojure 1.6.0
This is a bootstrap issue in clojurescript.
tools.reader 0.8.4 introduced :file metadata, clojurescript needs to dissoc it here https://github.com/clojure/clojurescript/blob/master/src/clj/cljs/analyzer.clj#L1490 to work with this version.
I suggest you open a ticket in che clojurescript jira making that change if you want to make clojurescript work with 0.8.4
Thank you very much Nicola, I opened the issue on the clojurescript JIRA