store/[org.clojure/clojure "1.8.0"] clj::clojure.core/*warn-on-reflection*

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Docstring
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  When set to true, the compiler will emit warnings when reflection is
  needed to resolve Java method calls or field accesses.

  Defaults to false.

Example 1

Edit
;; define two variables then set *warn-on-reflection* to true and try to call
;; one of their Java methods. Warnings are generated in both cases
;; set *warn-on-reflection* to false and note that you can call both functions
;; without a warning

(def i 23)
;; => #'user/i

(def s "123")
;; => #'user/s

(set! *warn-on-reflection* true)
;; => true

(.toString i)
;; > Reflection warning, NO_SOURCE_PATH:4 - reference to field toString can't be resolved.
;; => "23"

(.toString s)
;; > Reflection warning, NO_SOURCE_PATH:5 - reference to field toString can't be resolved.
;; => "123"

(set! *warn-on-reflection* false)
;; => false

(.toString i)
;; => "23"

(.toString s)
;; => "123"

Uses on crossclj