infer.cljs

(let [x (cons 1 nil)]
  (+ x 1))

;; WARNING: cljs.core/+, all arguments must be numbers, got [cljs.core/Cons number] instead.

(let [x (interleave (repeat "foo") (repeat "bar"))]
  (+ x 1))

;; WARNING: cljs.core/+, all arguments must be numbers, got [cljs.core/LazySeq number] instead.

@ericnormand interleave returns a lazy sequence, of characters in this case.

Note none of this is a replacement for what core.typed does, it's really only designed to handle the common non-higher order cases. If you need something more powerful than that, you know where to look :)

Getting the primitive arithmetic check in was just a fun way to kick off having more type information in the AST, the real benefit will be around eliminating protocol overheads where we can.

@frenchy64

(take 10 (interleave (repeat "foo") (repeat "bar"))) => ("foo" "bar" "foo" "bar" "foo" "bar" "foo" "bar" "foo" "bar")

@swannodette

It's definitely useful! Just wondering if it's a bug.

@ericnormand, sorry I understand the source of your confusion now, that vector is just the types of the argument list - the inference doesn't consider contents of collections - that's definitely outside the realm of what we want to handle in the ClojureScript compiler.