@bronsa: Tail clearing is broken in t.a.j. due to incorrect code analysis. Proper fix and explanation is in the commit message to http://dev.clojure.org/jira/browse/CLJ-1793

Turns out all loop bodies are analyzed in RETURN context even if the loop isn't RETURN context

@ghadi thanks I'll look into that

Minimal repro:

(let [x (atom 5)
      bad (fn []
            (loop [] (System/getProperties))
            (swap! x dec)
            (if (pos? @x)
              (recur)
              (count [])))]
 (bad))

That will NPE on 1.8.0-alpha4. (System/getProperties) is a tail call because loop bodies are always RETURN context

@ghadi seems to work fine in t.a.j, it's possible I already fixed that

cool. Wasn't certain you had taken the same (incorrect) approach that I did where C.RETURN == tail call

You probably don't do this in t.a.j https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/Compiler.java#L6333

Hmm, actually https://github.com/clojure/tools.analyzer/blob/master/src/main/clojure/clojure/tools/analyzer.clj#L514

@ghadi yeah, I need to take a better look. I just tried your testcase & the one on CLJ-1793 and they don't NPE in t.e.j but I don't recall how the clearing analysis work right now to confirm it's not affected

@ghadi does this bug manifests itself only with direct linking?

no, there was a separate bad interaction with direct linking

ok

i think the analysis pass is probably better than Compiler.java