In the source code I see the multi-method cljs.test/thrown? but when I tried to require it the compiler says that Invalid :refer, var cljs.test/thrown? does not exist. How come?

Because it’s just a symbol. There’s a multi method method that interprets it

Read the doc string of clojure.test

An issue filed on one of my repositories has this rather long Java stack trace and I have no idea where to begin. It compiles fine on my local. Any tips on how I should begin to diagnose this?

388 |   (go
---------^----------------------------------------------------------------------
Error in phase :compilation
StackOverflowError: 
	java.lang.ClassLoader.defineClass1 (ClassLoader.java:-2)
...