Using version 1.8.3.
The stack trace below seems to occur when a file is found in a source dir, and the file name and ns symbol within do not correspond. In my case, the file was not even a ".clj" file, but had clj source.
Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: -45
at java.lang.String.substring (String.java:1967)
at com.theoryinpractise.clojure.NamespaceDiscovery.findNamespaceInFile (NamespaceDiscovery.java:161)
at com.theoryinpractise.clojure.NamespaceDiscovery.discoverNamespacesIn (NamespaceDiscovery.java:133)
at com.theoryinpractise.clojure.NamespaceDiscovery.discoverNamespacesInPath (NamespaceDiscovery.java:108)
at com.theoryinpractise.clojure.NamespaceDiscovery.discoverNamespacesIn (NamespaceDiscovery.java:75)