Reflection warning when defining multimethods with *warn-on-reflection*

[Darshan Shaligram]

When experimenting with Clojure multimethods and *warn-on-reflection*
on Clojure svn r725, I found that defmethod produces this warning:

Reflection warning, line: 829 - call to assoc can't be resolved.

I'm guessing a type hint to clojure.lang.MultiFn in boot.clj:829 will
fix this. The code involved (admittedly silly) was:

(def *warn-on-reflection* true)
(defmulti laborious-evenp
(fn [x] (if (zero? (rem x 2)) :even :odd)))
(defmethod laborious-evenp :even [x] true)
(defmethod laborious-evenp :odd [x] false)

(I ran this test using clojure.lang.Script.)

I'm also wondering if it would be possible to show the source file
name in addition to the line number for warnings?

Thanks,
Darshan

[Rich Hickey]

On Mar 7, 2:50 pm, Darshan Shaligram <scinti...@gmail.com> wrote:
> When experimenting with Clojure multimethods and *warn-on-reflection*
> on Clojure svn r725, I found that defmethod produces this warning:
>
> Reflection warning, line: 829 - call to assoc can't be resolved.
>
> I'm guessing a type hint to clojure.lang.MultiFn in boot.clj:829 will
> fix this. The code involved (admittedly silly) was:
>
> (def *warn-on-reflection* true)
> (defmulti laborious-evenp
> (fn [x] (if (zero? (rem x 2)) :even :odd)))
> (defmethod laborious-evenp :even [x] true)
> (defmethod laborious-evenp :odd [x] false)
>

I've added the needed type hints to make this warning go away.

> I'm also wondering if it would be possible to show the source file
> name in addition to the line number for warnings?
>

Eventually, although, as in this case, it means communicating line #s
from macros, something I haven't gotten around to yet.

Rich