clojurescript compilation under :optimizations :simple

README.md

So this is the compilation I'm getting inside my larger project under :optimizations :simple (cljs 1.7.28)

The real problem is this:

Line 7 of the output code sets $_STAR_format_str_STAR_27199$$ = $_STAR_format_str_STAR_27199$$.indexOf("~") for line 12 in the input code of (let [tilde (.indexOf s \~)] ...).

Now, $_STAR_format_str_STAR_27199$$ seems to be standing in for s in the input code. Why is closure renaming tilde into overwriting s?

Later, at the end of line 9 (output) or line 15 (input), (subs s 1) / cljs.core.subs.call(null, $_STAR_format_str_STAR_27199$$, 1) causes an error because we have tilde, s and *format-str* sharing a variable name.

pprint.cljs

(def ^:dynamic ^{:private true} *format-str* nil)

...

(binding [*format-str* format-str]
  (process-nesting
    (first
      (consume
        (fn [[s offset]]
          (if (empty? s)
            [nil s]
            (let [tilde (.indexOf s \~)]
              (cond
                (neg? tilde) [(compile-raw-string s offset) ["" (+ offset (.-length s))]]
                (zero? tilde) (compile-directive (subs s 1) (inc offset))
                true
                [(compile-raw-string (subs s 0 tilde) offset) [(subs s tilde) (+ tilde offset)]]))))
        [format-str 0]))))

pprint.js

return function($format_str$$) {
  var $_STAR_format_str_STAR_27199$$ = cljs.core.nth.call(null, $format_str$$, 0, null);
  $format_str$$ = cljs.core.nth.call(null, $format_str$$, 1, null);
  if (cljs.core.empty_QMARK_.call(null, $_STAR_format_str_STAR_27199$$)) {
    return new cljs.core.PersistentVector(null, 2, 5, cljs.core.PersistentVector.EMPTY_NODE, [null, $_STAR_format_str_STAR_27199$$], null);
  }
  var $_STAR_format_str_STAR_27199$$ = $_STAR_format_str_STAR_27199$$.indexOf("~");
  return 0 > $_STAR_format_str_STAR_27199$$ ? new cljs.core.PersistentVector(null, 2, 5, cljs.core.PersistentVector.EMPTY_NODE, [cljs.pprint.compile_raw_string.call(null, $_STAR_format_str_STAR_27199$$, $format_str$$), new cljs.core.PersistentVector(null, 2, 5, cljs.core.PersistentVector.EMPTY_NODE, ["", $format_str$$ + $_STAR_format_str_STAR_27199$$.length], null)], null) : 0 === $_STAR_format_str_STAR_27199$$ ? cljs.pprint.compile_directive.call(null, cljs.core.subs.call(null, $_STAR_format_str_STAR_27199$$, 
  1), $format_str$$ + 1) : new cljs.core.PersistentVector(null, 2, 5, cljs.core.PersistentVector.EMPTY_NODE, [cljs.pprint.compile_raw_string.call(null, cljs.core.subs.call(null, $_STAR_format_str_STAR_27199$$, 0, $_STAR_format_str_STAR_27199$$), $format_str$$), new cljs.core.PersistentVector(null, 2, 5, cljs.core.PersistentVector.EMPTY_NODE, [cljs.core.subs.call(null, $_STAR_format_str_STAR_27199$$, $_STAR_format_str_STAR_27199$$), $_STAR_format_str_STAR_27199$$ + $format_str$$], null)], null);
};