distinct? cannot be invoked with zero arguments. When using the pattern (apply distinct? x), this is bothersome as you have to check whether x is empty or not. It is also logical that distinct? should return true if no arguments are given, since there are no duplicates.
What (small set of) steps will reproduce the problem?
user=> (apply distinct? )
ArityException Wrong number of args (0) passed to: core$distinct-QMARK- clojure.lang.AFn.throwArity (AFn.java:437)
What is the expected output? What do you see instead?
I would expect distinct? to return true whenever given zero arguments.
What version are you using?
This was tested under Clojure 1.4 and Clojure 1.5.