When you call a {{Keyword}} with the wrong number of arguments, the error message does not report how many arguments were passed:
(:kw "one" "two" "three")
=> java.lang.IllegalArgumentException: Wrong number of args passed to keyword: :kw
compare to calling an {{IFn}}, which does show the number of arguments passed:
(name "one" "two" "three")
=> clojure.lang.ArityException: Wrong number of args (3) passed to: core/name
The latter error message is more clear and makes it easier to debug.
The attached patch re-uses the {{ArityException}} class used elsewhere to generate error messages in the latter form when calling a keyword with the wrong number of arguments.
Addresses CLJ-1067
Patch: keyword-arity-exception-03.patch
Screened by: Alex Miller
