If CLJC is being used and the ClojureScript compiler sees Clojure type annotations, it should effecively ignore those where there isn't a portability concern.
The specific case for this ticket is {{^int}} and arithmetic, and a motivating example is:
cljs.user=> (let [^int v (alength (into-array []))] (+ v 3))
WARNING: cljs.core/+, all arguments must be numbers, got [int number] instead. at line 1 <cljs repl>
3
On the other hand, {{^long}} should still cause warnings to be emitted given that it is not a "subtype" of {{^number}} (such code might overflow, so warnings are helpful in that case).