an idea, could linter warn about using case with Java enums like

(let [x java.util.concurrent.TimeUnit/SECONDS]
  (case x
    java.util.concurrent.TimeUnit/SECONDS "secs"
    java.util.concurrent.TimeUnit/MINUTES "mins"))

how should clj-kondo know you're not actually matching against real symbols here?

yeah, I see that's one issue

I'd usually use keywords instead of symbols, but for me I'd say if the symbol matches an enum pattern some.Class/ENUM_VAL but that would perhaps be too opinionated as a general rule

would a type hint be usable here?

(let [^java.util.concurrent.TimeUnit x java.util.concurrent.TimeUnit/SECONDS] (case x …)) would then carry the “enum type” on x

it’s quite ugly lol but maybe clj-kondo could use it?