Useless for expression not reported as an unused value

[cjohansen]

• I have read the Clojure etiquette and will respect it when communicating on this platform.

version

borkdude/brew/clj-kondo: stable 2024.03.13

platform

via clojure-lsp

editor

Emacs, clojure-lsp

problem

I modified a Java object in a for, but since it's lazy and not returned or otherwise evaluated, the code never runs. This should probably be linted as an unused value?

repro

(defn map->Headers [headers]
  (let [headers-obj ^Headers (Headers.)]
    (for [[k v] headers]
      (->> (cond-> v
             (not (coll? v)) vector)
           (map str)
           (.add headers-obj (name k))))
    headers-obj))

expected behavior

I would have expected clj-kondo to inform me that the for here is useless.