Running through the new 1.10.x Quick Start on Windows, you can see that the stack trace is not source-mapped (referring to JavaScript line numbers).
cljs.user=> (ffirst [1])
Error: 1 is not ISeqable
Error: 1 is not ISeqable
at cljs$core$seq (http://localhost:9000/out/cljs/core.js:4457:1)
at cljs$core$first (http://localhost:9000/out/cljs/core.js:4476:1)
at cljs$core$ffirst (http://localhost:9000/out/cljs/core.js:5922:1)
at Anonymous function (eval code:1:55)
at Anonymous function (eval code:1:18)
at eval code (eval code:1:2)
at Anonymous function (http://localhost:9000/out/clojure/browser/repl.js:115:31)
at clojure$browser$repl$evaluate_javascript (http://localhost:9000/out/clojure/browser/repl.js:115:1)
at Anonymous function (http://localhost:9000/out/clojure/browser/repl.js:372:5)
at Anonymous function (http://localhost:9000/out/clojure/browser/repl.js:369:1)
Likewise source mapping not working in Node:
(This is after doing {{npm install source-map-support}}.)
cljs.user=> (ffirst [1])
Error: 1 is not ISeqable
at cljs$core$seq (C:\Users\mfikes\AppData\Local\Temp\out90041183794981196991184876870030\cljs\core.js:4457:1)
at cljs$core$first (C:\Users\mfikes\AppData\Local\Temp\out90041183794981196991184876870030\cljs\core.js:4476:1)
at cljs$core$ffirst (C:\Users\mfikes\AppData\Local\Temp\out90041183794981196991184876870030\cljs\core.js:5922:1)
at Anonymous function (repl:1:55)
at Anonymous function (repl:1:18)
at Global code (repl:1:2)
at exports.runInThisContext (vm.js:54:3)
at Anonymous function ([stdin]:76:29)
at Domain.prototype.run (domain.js:222:5)
at Anonymous function ([stdin]:73:25)
